基于草地植物空间格局的绵羊采食选择与植物联合防御研究
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摘要
在草地生态系统中，大型草食动物的采食选择（foraging selectivity of largeherbivore）和植物防御（plant defense）之间的互作关系是影响草地生态系统功能和稳定的重要关系之一。草食动物为了满足自身生长繁殖的营养需求而采取一系列采食策略来获取足够的食物。选择性采食是大型草食动物采食策略的核心内容。它不仅决定了动物自身的生长状况，还在很大程度上影响了草地植物群落结构和生态系统功能。植物为了适应或躲避动物的采食损害而衍生出一系列防御策略。植物联合防御（plant associational defense）是植物种群在空间上最重要的防御策略。它是指某一特定的目标植物由于其他邻居植物的存在，降低了动物对其采食，即目标植物与邻居植物联合防御动物的采食损害。植物联合防御主要体现在植物种内和种间的空间关系（spatial interaction）和空间格局上（spatial pattern）。在天然草地上，植物空间格局最典型的特点是呈斑块化（patchy）分布。不同物种在斑块内和斑块间的空间关系和空间分布格局影响草食动物采食选择以及植物联合防御策略的重要因素。由此，本研究以大型草食动物——绵羊作为研究对象，以植物空间格局为作用因素，以植物斑块为主要研究尺度探讨绵羊在斑块内植物个体水平（plant individual）、斑块水平（patch）、植物群落水平（plantcommunity）等多尺度上的食性选择机制，以及从动物选择性采食的角度揭示植物空间防御策略。本研究不仅能丰富动物采食理论，动、植物协同进化理论，同时，对于维持草地生态系统的稳定性、合理利用草地资源、制定有效的放牧管理政策都具有极其重要的实际指导意义。
本研究结合自助餐控制实验、人工草地放牧实验，以及天然草地放牧实验探讨绵羊的采食选择与植物联合防御互作关系，得出了以下实验结果：
（1）不同质量斑块内（高、中、低质量斑块）植物空间微格局（plant spatialmicro-pattern）模式（聚集分布和随机分布）对绵羊在植物个体和斑块水平上的采食选择影响的研究表明，当高质量斑块内植物空间微格局由聚集分布变成随机分布时，绵羊显著降低在高质量斑块偏食物种的采食量和总采食量（P <0.05），并且显著增加在中质量斑块和低质量斑块偏食物种的采食量和总采食量（P <0.05）；中、低质量斑块内的植物微格局的变化也会显著影响动物对高质量斑块偏食物种的采食量和总采食量。因此，斑块内植物空间微格局会影响动物在植物个体和斑块两个尺度上的采食选择。而且，微格局的作用强度与斑块质量有关，高质量斑块是微格局影响动物采食选择最敏感的采食区域。
（2）不同质量斑块内（高、中、低质量斑块）植物空间微格局模式（聚集分布和随机分布）能改变动物在斑块内和斑块间选择性强度，从而显著地影响动物对各个斑块内目标植物的采食，得到不同的植物联合防御效果。并且，微格局的作用效果与斑块质量有很大关系。高质量斑块内微格局的变化不影响动物在斑块内和斑块间采食选择性，目标植物芦苇（Phragmites australis）与邻居植物无联合防御效应（P>0.05）。但是，当低质量斑块内植物微格局由聚集分布变成随机分布时，动物在斑块间选择性显著降低（P <0.05），动物主要在斑块内植物个体水平进行采食判断。此时，目标植物在高质量斑块内，即与偏食物种构成邻居关系时受到保护，在低质量斑块内受害。此结果与吸引诱导假说（attractant-decoyhypothesis）的预测一致。当中质量斑块植物微格局变成随机分布时，虽然目标植物在各个斑块内无联合防御效果，但目标植物在各斑块的总采食量较其他微格局处理显著降低（P <0.05），即中质量斑块微格局变化会增加目标植物总体联合防御效果。因此，在放牧管理中，调控较低质量牧草区域的微格局分布模式，是保护目标物种的有效方式。
（3）本研究通过盆栽控制实验进一步探讨了斑块质量对绵羊采食选择性和植物联合防御的影响。结果表明，绵羊的采食选择主要发生在斑块内植物个体水平。由此带来的植物联合防御结果是，当目标植物与偏食物种构成邻居关系时，目标植物可以成功躲避动物采食。但是，当各斑块质量发生变化，斑块间质量差异变大，绵羊在斑块内选择性下降，在斑块间选择性增强，绵羊则避免到低质量斑块采食。则此时目标植物在低质量斑块与低偏食物种构成邻居关系时受到保护。因此，随着斑块间质量差异增加，动物采食选择主要发生的尺度由斑块内转变成斑块间，从而目标植物联合防御的位置也从高质量斑块转移到低质量斑块。本研究通过分析绵羊对不同质量斑块的采食响应策略，进一步证明了绵羊采食策略的多尺度特点和植物联合防御的基本机制，即植物联合防御效果取决于动物采食选择性发生的主要尺度。调节各斑块质量差异是改变动物采食选择性的有效方式，也是预测目标植物联合防御结果的重要依据。在草地放牧管理中，通过调节局部草地斑块质量可以达到对特定区域中目标物种的保护。
（4）本研究采用人工种植放牧地方法，检验了目标植物全叶马兰（Kalimerisintegrifolia）、偏食物种五脉山黧豆（Lathyrus quinquenervius）和非偏食物种羊草（Leymus chinensis）五种空间分布格局（全叶马兰聚集分布，五脉山黧豆和羊草随机分布；全叶马兰一部分聚集分布，一部分与五脉山黧豆、羊草随机分布；全叶马兰与五脉山黧豆构成邻居关系形成3个斑块，羊草为背景植物；全叶马兰与羊草构成邻居植物形成3个斑块，五脉山黧豆为背景植物；三种物种全部随机分布）对绵羊采食选择及植物联合防御的影响。实验结果表明，当目标植物聚集分布或3种物种随机分布时，绵羊对目标植物采食量较高（66.43g，P <0.05）；当植物分布格局变得复杂时，特别是当目标植物部分聚集部分随机分布时，绵羊对其采食量最小（9.21g，P <0.05），即此时目标植物防御动物采食效果最显著。由于此时目标植物没有与其他两种植物构成邻居关系存在于斑块内，只有目标植物种群本身的以复杂的空间分布策略来防御动物采食，我们称这种防御为种群内联合防御。当目标植物与其他两种植物构成邻居关系时，绵羊对其采食量较低（25.89g，16.73g），此时，目标植物的空间防御策略为种间联合防御。本研究提出目标植物可能以种内防御与种间防御共存策略适应动物采食。目标植物空间分布模式的复杂化是目标植物种群最优的空间防御策略。本研究不仅从植物种内防御的视角进一步丰富了植物联合防御理论，而且对于解释动植物互作关系、物种共存机制、维持草地生态系统中动、植物稳定共存提供了实验依据。
（5）本研究通过天然草地放牧实验，探讨了目标植物全叶马兰在种群和群落两个水平的空间分布格局（全叶马兰聚集分布，全叶马兰随机分布，全叶马兰与邻居植物聚集分布，全叶马兰与邻居植物随机分布）对绵羊多尺度采食选择的影响。实验结果表明，当全叶马兰随机分布时，绵羊对全叶马兰的采食量显著高于聚集分布时的采食量（P <0.05）；但当全叶马兰有邻居植物存在时，聚集分布较随机分布更有利于动物对全叶马兰的采食（P <0.05）。这说明邻居植物存在影响了绵羊在种群水平上的采食判断，即植物群落的空间分布模式影响绵羊对某一目标植物种群的采食选择。此外，目标植物全叶马兰的空间分布模式也影响了动物对邻居植物的采食，即动物在种群水平上的采食判断影响了动物在群落水平上的采食选择。因此，本研究证明，动物在较高尺度上的采食行为可以制约较低尺度食性选择，而在较低尺度的采食判断也能影响动物在大尺度的采食策略。揭示动物这种多尺度采食策略互作机制不仅进一步验证了动物采食等级理论，而且在解释放牧生态系统植物群落结构、空间防御策略上也能提相应的实验依据。同时，本研究也对制定合理的放牧管理政策、调控动物的采食分布、保护草地生态环境上都有重要的意义。
本研究在复杂的草地植物空间分布格局背景下，通过对大型草食动物绵羊的采食行为响应机制和植物联合防御策略深入系统的研究，获得了对草食动物采食行为及植物联合防御互作关系的深入理解和进一步认识：草食动物的采食过程是动物在各个尺度上一系列采食策略整合的结果；不同尺度采食策略相互影响相互制约；而植物联合防御依赖于草食动物的采食选择主要发生的空间尺度。草食动物与植物这种互作关系是决定草地生态过程的关键因素，具有重要的生态意义。草地植物空间格局的复杂性是调控草地动、植物之间互惠与稳定共存的重要基础。本研究对草地放牧管理、植物保护、合理利用草地空间资源都具有重要的实际指导意义。
In grassland ecosystem, the interaction between foraging selectivity of largeherbivore and plant defense is one of the important relationships that impactecosystem function and stability. In order to satisfy nutrition need for growing andproducing, large herbivore adopt a series of foraging strategies to obtain sufficientfood. Selective foraging is the core of herbivore foraging strategies. It not only affectsthe growth and productivity of herbivore themselves, but also influences thecomposition of plant communities and ecosystem stability. In order to escape or adaptherbivore foraging damage, plant has been evolved a series of defense policies. Plantassociational defense is one of the most important spatial defense policies of plantcommunities. It is defined as the focal plant is less damaged by herbivore because ofthe existence of neighbor plant. In other words, the focal plant resist against herbivoreforaging together with the neighbor plant. Plant associational defense always includesspatial interaction and spatial pattern among inter-or intra-plant species. Distributionof vegetation patch is a typical character of natural grasslands. Spatial interaction andspatial pattern of different plant species between-and within-patch are the vitalfactors that influence both herbivore foraging and plant associational defense policy.In this paper, we use sheep as the representative of large herbivore, to explain theirforaging mechanism as affected by plant spatial pattern as plant individual, patch andplant community scales, and to reveal the plant spatial defense polices in response ofherbivore foraging. This study will not only enrich the foraging theory andcoevolution theory between herbivore and plant, but also has the applied directivevalue in maintaining the stability of grazing grassland system, rational utilization ofgrassland resources and making effective grazing management policies.
Combining the manipulated cafeteria trials, artificially grassland grazingexperiments and experiments in natural grassland, we obtained the important resultsand conclusions as follows.
(1) Plant spatial micro-pattern within different quality patches can significantlyaffect sheep foraging both at plant individual scale and at between patch scale. Whenplant micro-pattern within high quality patch changed from clumped to random, sheepconsumption of both preferred species and total intake in high quality patch wasdecreased (P <0.05), and increased the consumption of preferred species and totalintake in medium and low quality patches (P <0.05). In addition, as plantmicro-pattern in medium or low quality patch changed from clumped to random,sheep foraging selectivity in high quality patch will be influenced. Therefore, plantspatial micro-pattern can greatly affect sheep foraging selectivity at both within-andbetween-patch scales. And the intensity of these effects was related to patch quality. High quality resource sites was the most influential and susceptible foraging area.
(2) Plant spatial micro-pattern within different quality patch significantly canaffect sheep foraging selectivity between-and within-patch, and thus affected theconsumption of focal plant by herbivore, thereby come up with different results ofplant associational defense. Patch quality also played an important role in this effect.When plant micro-pattern changed from clumped to random in high quality patch,sheep forging selectivity was not affected (P>0.05), and there was no plantassociational defense for focal plant (Phragmites australis). However, when plantspatial micro-pattern changed in low quality patch, sheep foraging selectivitybetween-patch declined (P <0.05). Sheep foraging decision was made mainly atwithin-patch (plant individual) scale, and focal plant gained protection when it existedin high quality patch and suffered injury in low quality patch. This was consistentwith the prediction of attractant-decoy hypothesis. Besides, when plant micro-patternbecame random in medium quality patch, although there was no plant associationaldefense of focal plant in each patch, the total intake of focal plant in all patches wassignificantly lower than other plant spatial micro-patterns (P <0.05). Therefore, plantmicro-pattern in medium quality patch will affect focal plant associational defensewithin the whole plot. To sum up, regulating the plant spatial micro-pattern in lowerquality grass resource is an effective way to protect focal plant in grazingmanagement.
(3) We studied the effects of patch quality on sheep foraging selectivity and plantassociational defense. The results showed that Sheep foraging selectivity occurredmainly in plant individual scale, and the focal plant will escape foraging by sheepwhen it had good neighbor in high quality patch. When the difference of patch qualitybetween patches become great, sheep foraging selectivity at patch scale will increasedand selectivity at within patch (plant individual scale) will decreased. Sheep decreasedthe visits to low quality patch. Hence, focal plant with bad neighbor in lower qualitypatch will gain protection. Thus, as the difference between patches increased, mainlyscale of sheep foraging decision was changed from within-patch to between-patch.The protection site for focal plant changed from high quality patch to low qualitypatch. This study investigated the foraging responses of sheep to different qualitypatches and demonstrated sheep made foraging decisions at multiple spatial scalesand this induced different plant associational defense. Regulation patch quality was aneffective way to change herbivore foraging selectivity and predict the results of plantassociational defense. It was important to protect special plant species throughcontrolling local patch quality in grassland grazing management.
(4) We investigated the effects of five plant spatial distribution pattern of focalplan（tKalimeris integrifolia）, high preference plant Lathyrus quinquenervius and lowpreference plant Leymus chinensis on sheep foraging behavior and plant associationaldefense (focal plant distributed clumped and the other two species distributed randomly; half of focal plant distributed clumped, half of it distributed randomly withthe other two species; focal plant distributed in three patches with high preferencespecies as neighbors, low preference species as background plants; focal plantdistributed in three patches with low preference species as neighbors, high preferencespecies as background plants; three species distributed randomly). The results are asfollows: sheep obtained the most intake of focal pant when focal plant distributedtotally clumped, or when focal plant distributed totally randomly (66.43g，P <0.05).As plant spatial pattern became complicated, sheep intake of focal plant was leastwhen half of the focal plant distributed clumped and half of it distributed randomly(9.21g，P <0.05). The defense of focal plant is most effective under this spatialpattern. Because there was no neighbor in this pattern, focal plant defend herbivoreforaging mainly by its own distribution pattern, we assume this defense intra-speciesassociational defense. When focal plant had spatial relationship with other species(neighbor plants), the consumption by sheep was also low (25.89g，16.73g). It wasdefined as plant inter-species associational defense. Thus, we highlighted focal plantexisted both intra-and inter-species associational defense. The complex ofdistribution pattern was the best spatial defense policy. This conclusion not onlydevelops the plant associational theory, but also interprets the mechanisms of speciescoexists. Our study also has the great value in sustaining the stability ofplant-herbivore relationship in grassland ecosystem.
(5) Based on foraging experiment in natural grassland environment, we test theeffects of plant spatial distribution pattern at multiple scales on sheep foragingbehavior (clumped distribution focal plant; random distribution of focal plant;clumped distribution when focal plant together with neighbors; random distributionwhen focal plant together with neighbors). Results were as follows: focal plant wasconsumed by sheep more in random distribution pattern than in clumped distributionpattern (P <0.05). When neighbor plant existed, focal plant was consumed less inrandom pattern than in clumped pattern (P <0.05). This indicated that the existence ofneighbor plant disturbed sheep’s judgments on patch scale. Distribution pattern atplant community scale influenced sheep foraging at plant population scale.Meanwhile, the plant spatial distribution pattern at population scale also affectedsheep foraging selectivity at plant community scale. Distribution pattern of focal plantpatches influenced the sheep foraging selection of neighbor plants. In conclusion,foraging decision of large herbivore at coarser scales can constrain the diet selectionat finer scales, and grazing decision at finer scale can also affect the foragingjudgments at coarser scales. Studies on foraging behavior of herbivore at multiplescales can not only enrich the foraging hierarchy theory, but also have appliedimportance in regulating foraging distribution and protecting specific plant species inestablishing grazing management policies.
Our study has investigated sheep foraging selectivity and plant associational defense in response to complicated plant spatial pattern, and we acquired the furtherknowledge and insights into the relationship between plant and animal. Foragingprocess of herbivore is the results integration of foraging decisions making at differentspatial scales. Foraging decisions at different scales will affect and constrain eachother. Plant associational defense is the final results of the interaction of decisions ateach scale. This relationship between herbivore foraging and plant defense is a vitalfactor influencing grassland ecosystem functions and stability. The complexity andheterogeneity of plant spatial pattern is important and significant to ensure largegeneralist herbivore–plant ‘mutualisms’ and stable coexistence. This study furtheremphasized the importance for grazing management, protecting grassland plantdiversity and rational use of grassland recourses.
本研究结合自助餐控制实验、人工草地放牧实验，以及天然草地放牧实验探讨绵羊的采食选择与植物联合防御互作关系，得出了以下实验结果：
（1）不同质量斑块内（高、中、低质量斑块）植物空间微格局（plant spatialmicro-pattern）模式（聚集分布和随机分布）对绵羊在植物个体和斑块水平上的采食选择影响的研究表明，当高质量斑块内植物空间微格局由聚集分布变成随机分布时，绵羊显著降低在高质量斑块偏食物种的采食量和总采食量（P <0.05），并且显著增加在中质量斑块和低质量斑块偏食物种的采食量和总采食量（P <0.05）；中、低质量斑块内的植物微格局的变化也会显著影响动物对高质量斑块偏食物种的采食量和总采食量。因此，斑块内植物空间微格局会影响动物在植物个体和斑块两个尺度上的采食选择。而且，微格局的作用强度与斑块质量有关，高质量斑块是微格局影响动物采食选择最敏感的采食区域。
（2）不同质量斑块内（高、中、低质量斑块）植物空间微格局模式（聚集分布和随机分布）能改变动物在斑块内和斑块间选择性强度，从而显著地影响动物对各个斑块内目标植物的采食，得到不同的植物联合防御效果。并且，微格局的作用效果与斑块质量有很大关系。高质量斑块内微格局的变化不影响动物在斑块内和斑块间采食选择性，目标植物芦苇（Phragmites australis）与邻居植物无联合防御效应（P>0.05）。但是，当低质量斑块内植物微格局由聚集分布变成随机分布时，动物在斑块间选择性显著降低（P <0.05），动物主要在斑块内植物个体水平进行采食判断。此时，目标植物在高质量斑块内，即与偏食物种构成邻居关系时受到保护，在低质量斑块内受害。此结果与吸引诱导假说（attractant-decoyhypothesis）的预测一致。当中质量斑块植物微格局变成随机分布时，虽然目标植物在各个斑块内无联合防御效果，但目标植物在各斑块的总采食量较其他微格局处理显著降低（P <0.05），即中质量斑块微格局变化会增加目标植物总体联合防御效果。因此，在放牧管理中，调控较低质量牧草区域的微格局分布模式，是保护目标物种的有效方式。
（3）本研究通过盆栽控制实验进一步探讨了斑块质量对绵羊采食选择性和植物联合防御的影响。结果表明，绵羊的采食选择主要发生在斑块内植物个体水平。由此带来的植物联合防御结果是，当目标植物与偏食物种构成邻居关系时，目标植物可以成功躲避动物采食。但是，当各斑块质量发生变化，斑块间质量差异变大，绵羊在斑块内选择性下降，在斑块间选择性增强，绵羊则避免到低质量斑块采食。则此时目标植物在低质量斑块与低偏食物种构成邻居关系时受到保护。因此，随着斑块间质量差异增加，动物采食选择主要发生的尺度由斑块内转变成斑块间，从而目标植物联合防御的位置也从高质量斑块转移到低质量斑块。本研究通过分析绵羊对不同质量斑块的采食响应策略，进一步证明了绵羊采食策略的多尺度特点和植物联合防御的基本机制，即植物联合防御效果取决于动物采食选择性发生的主要尺度。调节各斑块质量差异是改变动物采食选择性的有效方式，也是预测目标植物联合防御结果的重要依据。在草地放牧管理中，通过调节局部草地斑块质量可以达到对特定区域中目标物种的保护。
（4）本研究采用人工种植放牧地方法，检验了目标植物全叶马兰（Kalimerisintegrifolia）、偏食物种五脉山黧豆（Lathyrus quinquenervius）和非偏食物种羊草（Leymus chinensis）五种空间分布格局（全叶马兰聚集分布，五脉山黧豆和羊草随机分布；全叶马兰一部分聚集分布，一部分与五脉山黧豆、羊草随机分布；全叶马兰与五脉山黧豆构成邻居关系形成3个斑块，羊草为背景植物；全叶马兰与羊草构成邻居植物形成3个斑块，五脉山黧豆为背景植物；三种物种全部随机分布）对绵羊采食选择及植物联合防御的影响。实验结果表明，当目标植物聚集分布或3种物种随机分布时，绵羊对目标植物采食量较高（66.43g，P <0.05）；当植物分布格局变得复杂时，特别是当目标植物部分聚集部分随机分布时，绵羊对其采食量最小（9.21g，P <0.05），即此时目标植物防御动物采食效果最显著。由于此时目标植物没有与其他两种植物构成邻居关系存在于斑块内，只有目标植物种群本身的以复杂的空间分布策略来防御动物采食，我们称这种防御为种群内联合防御。当目标植物与其他两种植物构成邻居关系时，绵羊对其采食量较低（25.89g，16.73g），此时，目标植物的空间防御策略为种间联合防御。本研究提出目标植物可能以种内防御与种间防御共存策略适应动物采食。目标植物空间分布模式的复杂化是目标植物种群最优的空间防御策略。本研究不仅从植物种内防御的视角进一步丰富了植物联合防御理论，而且对于解释动植物互作关系、物种共存机制、维持草地生态系统中动、植物稳定共存提供了实验依据。
（5）本研究通过天然草地放牧实验，探讨了目标植物全叶马兰在种群和群落两个水平的空间分布格局（全叶马兰聚集分布，全叶马兰随机分布，全叶马兰与邻居植物聚集分布，全叶马兰与邻居植物随机分布）对绵羊多尺度采食选择的影响。实验结果表明，当全叶马兰随机分布时，绵羊对全叶马兰的采食量显著高于聚集分布时的采食量（P <0.05）；但当全叶马兰有邻居植物存在时，聚集分布较随机分布更有利于动物对全叶马兰的采食（P <0.05）。这说明邻居植物存在影响了绵羊在种群水平上的采食判断，即植物群落的空间分布模式影响绵羊对某一目标植物种群的采食选择。此外，目标植物全叶马兰的空间分布模式也影响了动物对邻居植物的采食，即动物在种群水平上的采食判断影响了动物在群落水平上的采食选择。因此，本研究证明，动物在较高尺度上的采食行为可以制约较低尺度食性选择，而在较低尺度的采食判断也能影响动物在大尺度的采食策略。揭示动物这种多尺度采食策略互作机制不仅进一步验证了动物采食等级理论，而且在解释放牧生态系统植物群落结构、空间防御策略上也能提相应的实验依据。同时，本研究也对制定合理的放牧管理政策、调控动物的采食分布、保护草地生态环境上都有重要的意义。
本研究在复杂的草地植物空间分布格局背景下，通过对大型草食动物绵羊的采食行为响应机制和植物联合防御策略深入系统的研究，获得了对草食动物采食行为及植物联合防御互作关系的深入理解和进一步认识：草食动物的采食过程是动物在各个尺度上一系列采食策略整合的结果；不同尺度采食策略相互影响相互制约；而植物联合防御依赖于草食动物的采食选择主要发生的空间尺度。草食动物与植物这种互作关系是决定草地生态过程的关键因素，具有重要的生态意义。草地植物空间格局的复杂性是调控草地动、植物之间互惠与稳定共存的重要基础。本研究对草地放牧管理、植物保护、合理利用草地空间资源都具有重要的实际指导意义。
In grassland ecosystem, the interaction between foraging selectivity of largeherbivore and plant defense is one of the important relationships that impactecosystem function and stability. In order to satisfy nutrition need for growing andproducing, large herbivore adopt a series of foraging strategies to obtain sufficientfood. Selective foraging is the core of herbivore foraging strategies. It not only affectsthe growth and productivity of herbivore themselves, but also influences thecomposition of plant communities and ecosystem stability. In order to escape or adaptherbivore foraging damage, plant has been evolved a series of defense policies. Plantassociational defense is one of the most important spatial defense policies of plantcommunities. It is defined as the focal plant is less damaged by herbivore because ofthe existence of neighbor plant. In other words, the focal plant resist against herbivoreforaging together with the neighbor plant. Plant associational defense always includesspatial interaction and spatial pattern among inter-or intra-plant species. Distributionof vegetation patch is a typical character of natural grasslands. Spatial interaction andspatial pattern of different plant species between-and within-patch are the vitalfactors that influence both herbivore foraging and plant associational defense policy.In this paper, we use sheep as the representative of large herbivore, to explain theirforaging mechanism as affected by plant spatial pattern as plant individual, patch andplant community scales, and to reveal the plant spatial defense polices in response ofherbivore foraging. This study will not only enrich the foraging theory andcoevolution theory between herbivore and plant, but also has the applied directivevalue in maintaining the stability of grazing grassland system, rational utilization ofgrassland resources and making effective grazing management policies.
Combining the manipulated cafeteria trials, artificially grassland grazingexperiments and experiments in natural grassland, we obtained the important resultsand conclusions as follows.
(1) Plant spatial micro-pattern within different quality patches can significantlyaffect sheep foraging both at plant individual scale and at between patch scale. Whenplant micro-pattern within high quality patch changed from clumped to random, sheepconsumption of both preferred species and total intake in high quality patch wasdecreased (P <0.05), and increased the consumption of preferred species and totalintake in medium and low quality patches (P <0.05). In addition, as plantmicro-pattern in medium or low quality patch changed from clumped to random,sheep foraging selectivity in high quality patch will be influenced. Therefore, plantspatial micro-pattern can greatly affect sheep foraging selectivity at both within-andbetween-patch scales. And the intensity of these effects was related to patch quality. High quality resource sites was the most influential and susceptible foraging area.
(2) Plant spatial micro-pattern within different quality patch significantly canaffect sheep foraging selectivity between-and within-patch, and thus affected theconsumption of focal plant by herbivore, thereby come up with different results ofplant associational defense. Patch quality also played an important role in this effect.When plant micro-pattern changed from clumped to random in high quality patch,sheep forging selectivity was not affected (P>0.05), and there was no plantassociational defense for focal plant (Phragmites australis). However, when plantspatial micro-pattern changed in low quality patch, sheep foraging selectivitybetween-patch declined (P <0.05). Sheep foraging decision was made mainly atwithin-patch (plant individual) scale, and focal plant gained protection when it existedin high quality patch and suffered injury in low quality patch. This was consistentwith the prediction of attractant-decoy hypothesis. Besides, when plant micro-patternbecame random in medium quality patch, although there was no plant associationaldefense of focal plant in each patch, the total intake of focal plant in all patches wassignificantly lower than other plant spatial micro-patterns (P <0.05). Therefore, plantmicro-pattern in medium quality patch will affect focal plant associational defensewithin the whole plot. To sum up, regulating the plant spatial micro-pattern in lowerquality grass resource is an effective way to protect focal plant in grazingmanagement.
(3) We studied the effects of patch quality on sheep foraging selectivity and plantassociational defense. The results showed that Sheep foraging selectivity occurredmainly in plant individual scale, and the focal plant will escape foraging by sheepwhen it had good neighbor in high quality patch. When the difference of patch qualitybetween patches become great, sheep foraging selectivity at patch scale will increasedand selectivity at within patch (plant individual scale) will decreased. Sheep decreasedthe visits to low quality patch. Hence, focal plant with bad neighbor in lower qualitypatch will gain protection. Thus, as the difference between patches increased, mainlyscale of sheep foraging decision was changed from within-patch to between-patch.The protection site for focal plant changed from high quality patch to low qualitypatch. This study investigated the foraging responses of sheep to different qualitypatches and demonstrated sheep made foraging decisions at multiple spatial scalesand this induced different plant associational defense. Regulation patch quality was aneffective way to change herbivore foraging selectivity and predict the results of plantassociational defense. It was important to protect special plant species throughcontrolling local patch quality in grassland grazing management.
(4) We investigated the effects of five plant spatial distribution pattern of focalplan（tKalimeris integrifolia）, high preference plant Lathyrus quinquenervius and lowpreference plant Leymus chinensis on sheep foraging behavior and plant associationaldefense (focal plant distributed clumped and the other two species distributed randomly; half of focal plant distributed clumped, half of it distributed randomly withthe other two species; focal plant distributed in three patches with high preferencespecies as neighbors, low preference species as background plants; focal plantdistributed in three patches with low preference species as neighbors, high preferencespecies as background plants; three species distributed randomly). The results are asfollows: sheep obtained the most intake of focal pant when focal plant distributedtotally clumped, or when focal plant distributed totally randomly (66.43g，P <0.05).As plant spatial pattern became complicated, sheep intake of focal plant was leastwhen half of the focal plant distributed clumped and half of it distributed randomly(9.21g，P <0.05). The defense of focal plant is most effective under this spatialpattern. Because there was no neighbor in this pattern, focal plant defend herbivoreforaging mainly by its own distribution pattern, we assume this defense intra-speciesassociational defense. When focal plant had spatial relationship with other species(neighbor plants), the consumption by sheep was also low (25.89g，16.73g). It wasdefined as plant inter-species associational defense. Thus, we highlighted focal plantexisted both intra-and inter-species associational defense. The complex ofdistribution pattern was the best spatial defense policy. This conclusion not onlydevelops the plant associational theory, but also interprets the mechanisms of speciescoexists. Our study also has the great value in sustaining the stability ofplant-herbivore relationship in grassland ecosystem.
(5) Based on foraging experiment in natural grassland environment, we test theeffects of plant spatial distribution pattern at multiple scales on sheep foragingbehavior (clumped distribution focal plant; random distribution of focal plant;clumped distribution when focal plant together with neighbors; random distributionwhen focal plant together with neighbors). Results were as follows: focal plant wasconsumed by sheep more in random distribution pattern than in clumped distributionpattern (P <0.05). When neighbor plant existed, focal plant was consumed less inrandom pattern than in clumped pattern (P <0.05). This indicated that the existence ofneighbor plant disturbed sheep’s judgments on patch scale. Distribution pattern atplant community scale influenced sheep foraging at plant population scale.Meanwhile, the plant spatial distribution pattern at population scale also affectedsheep foraging selectivity at plant community scale. Distribution pattern of focal plantpatches influenced the sheep foraging selection of neighbor plants. In conclusion,foraging decision of large herbivore at coarser scales can constrain the diet selectionat finer scales, and grazing decision at finer scale can also affect the foragingjudgments at coarser scales. Studies on foraging behavior of herbivore at multiplescales can not only enrich the foraging hierarchy theory, but also have appliedimportance in regulating foraging distribution and protecting specific plant species inestablishing grazing management policies.
Our study has investigated sheep foraging selectivity and plant associational defense in response to complicated plant spatial pattern, and we acquired the furtherknowledge and insights into the relationship between plant and animal. Foragingprocess of herbivore is the results integration of foraging decisions making at differentspatial scales. Foraging decisions at different scales will affect and constrain eachother. Plant associational defense is the final results of the interaction of decisions ateach scale. This relationship between herbivore foraging and plant defense is a vitalfactor influencing grassland ecosystem functions and stability. The complexity andheterogeneity of plant spatial pattern is important and significant to ensure largegeneralist herbivore–plant ‘mutualisms’ and stable coexistence. This study furtheremphasized the importance for grazing management, protecting grassland plantdiversity and rational use of grassland recourses.
引文
[1]王岭.大型草食动物采食对植物多样性与空间格局的响应及行为适应机制[D]：[博士学位论文].长春：东北师范大学草地科学研究所，2010.
[2] Crawley M J. Herbivory: The Dynamics of Animal-Plant Interactions[M]. Oxford, UK:Blackwell Scientific Publications,1983.
[3] Atsatt P R, O'Dowd D J. Plant defense guilds[J]. Science,1976,193:24-29.
[4] Adler P B, Raff D A, Lauenroth W K. The effect of grazing on the spatial heterogeneity ofvegetation[J]. Oecologia,2001,128:465-479.
[5] Griffin J N, Jenkins S R, Gamfeldt L, et al. Spatial heterogeneity increases the importance ofspecies richness foran ecosystem process [J]. Oikos,2009,118:1335-1342.
[6] Li H, Reynolds J F. On definition and quantification of heterogeneity[J]. Oikos,1995,73:280-284.
[7]张金屯.数量生态学[M].北京：科学出版社，2004.
[8] Baraza E, Zamora R, Ho′dar J A. Conditional outcomes in plant-herbivore interactions:Neighbours matter[J]. Oikos,2006,113:148-156.
[9] WallisDeVries M F. Effects of resource distribution patterns on ungulate foraging behaviour:a modellingapproach[J]. Forest Ecol Manage,1996,88:167-177.
[10] Forbes J M. Consequences of feeding for future feeding[J]. Comp Biochem Physiol,2001,128:461-468.
[11] Wilmshurst J F, Fryxell JM, Hudsonb R J. Forage quality and patch choice by wapiti(Cervuselaphus)[J]. Behav Ecol,1995,6:209-217.
[12] Fisher D S. A review of a few key factors regulating voluntary feed intake in ruminants[J].Crop Science,2002,42(5):1651-1655.
[13] Charnov E L. Optimal foraging, the marginal value theorem[J]. Theo Popul Biol,1976,9:129-136.
[14] Parsons A J, Dumont B. Spatial heterogeneity and grazing processes[J]. Anim. Res,2003,52:161-180.
[15] Illius A W, Gordon I J, Elston D A, et al. Diet selection in goats: A test of intake-ratemaximization[J]. Ecology,1999,80(3):1008-1018.
[16] Schoener T. Theory of feeding strategies[J]. Annu Rev Ecol Syst,1971,2:369-404.
[17] Proulx M, Mazumder A. Reversal of grazing impact on plant species richness in nutrient-poorvs. nutrient-rich ecosystems[J]. Ecology,1998,79:2581-2592.
[18] Milchunas D G, Lauenroth W K. Quantitative effects of grazing on vegetation and soils over aglobal range of environments[J]. Ecol Monogr,1993,63:327-366.
[19] Olff H, Ritchie M E. Effects of herbivores on grassland plant diversity[J]. Trends Ecol Evol,1998,13:261-265.
[20]刘颖，王德利，王旭，等.放牧强度对羊草草地植被特征的影响[J].草业学报,2002,11(2):22-28.
[21] Frank D A. The interactive effects of grazing ungulates and aboveground production ongrassland diversity[J]. Oecologia,2005,143:629-634.
[22]刘鞠善.大型草食动物采食对植物多样性与空间格局的响应及行为适应机制[D]：[博士学位论文].长春：东北师范大学草地科学研究所，2011.
[23] Nolte D L, Mason J R, Lewis S L. Tolerance of bitter compounds by an herbivore,Caviaporcellus[J]. J Chem Ecol,1994,20:303-308.
[24] Molan A P, Duncan A, Barry T N, et al. Effects of condensed tannins and sesquiterpenelactones extracted from chicory on the viability of deer lungworm larvae[J]. Proc NewZealand Soc Anim Prod,2000,60:26-29.
[25] Molan A, Waghorn G C, Min B R, et al. The effect of condensed tannins from seven herbageson Trichostrongylus colubriformis larval migration in vitro[J]. Folia Parasit,2000,47:39-44.
[26] Thomes D W, Sanson C, Bergeron J M. Metabolic cost associated with the ingestion of planphenolics by Microtus pennsylvanicus[J]. J Mammal,1988,69:512-515.
[27] Athanasiadou S, Kyriazakis I. Plant secondary metabolites: antiparasitic effects and their rolein ruminant production systems[J]. P Nutr Soc,2004,63:631-639.
[28] Feeny P. Seasonal changes in oak leaf tannins and nutrients as a cause of spring feeding bywinter moth caterpillars[J]. Ecology,1970,51:565-581.
[29] Wang J, Provenza F D. Dynamics of preference by sheep offered foods varying in flavors,nutrients, and a toxin[J]. J Chem Ecol,1997,23:275-288.
[30] Dearing D M, Cork S. Role of detoxification of plant secondary compounds on diet breadthin a mammalian herbivore (Trichosurus vulpecula)[J]. J Chem Ecol,1999,25:1205-1219.
[31] Wiggins N L, McArthur C, McLean S, et al. Effects of two plant secondary metabolites,cineole and gallic acid, on nightly feeding patterns of the common brushtail possum[J]. JChem Ecol,2003,29:1423-1440.
[32] Lindroth R L, Batzli G. Plant phenolics as chemical defences: effects of natural phenolics onsurvival and growth of prairie voles (Microtus ochragaster)[J]. J Chem Ecol,1984,10:229-244.
[33]滕星，王德利，程志茹，等.不同放牧强度下绵羊采食方式的变化特征[J].草业学报,2004,13(2):67-72.
[34]巴雷，王德利，高莹.松嫩平原优势种羊草与其主要伴生种芦苇空间分布格局分析[J].草业学报,2005,14(5):111-116.
[35]巴雷，王德利，刘颖，等.羊草与其主要伴生种竞争与共存的格局分析[J].应用生态学报,2002,13(1):50-54.
[36]王岭，王德利.放牧家畜食性选择机制研究进展[J].应用生态学报,2007,18(1):205-211.
[37] Parsons A J, Newman J A, Penning P D, et al. Diet preference of sheep: effects of recent diet,physiological state and species abundance[J]. J Anim Ecol,1994,63:456-478.
[38] Senft R L, Coughenour M B, Bailey D W, et al. Large herbivore foraging and ecologicalhierarchies[J]. Bioscience,1987,37:789-795.
[39] Bailey D W, Gross J E, Laca E A, et al. Mechanisms that result in large herbivore grazingdistribution patterns[J]. J Range Manage,1996,49(5):386-400.
[40]王德利，程志茹.放牧家畜的采食行为理论研究[J].草业科学,2002,5（增刊）:114-121.
[41] Shipley L A, Gross J E, Spalinger D E, et al. The scaling of intake rate in mammalianherbivores[J]. Am Nat,1994,143:1055-1082.
[42] Fortin D, Fryxell J M, Pilote R. The temporal scale of foraging decisions in bison[J]. Ecology,2002,83:970-982.
[43] Lima S L, Zollner P A. Towards a behavioral ecology of ecological landscapes[J]. TrendsEcol Evol,1996,11:131-135.
[44] Illius A W, Clark D A, Hodgson J. Discrimination and patch choice by sheep grazinggrass-clover swards[J]. J Anim Ecol,1992,61:183-194.
[45] Kotliar N B, Wiens J A. Multiple scales of patchiness and patch structure: a hierarchicalframework for the study of heterogeneity[J]. Oikos,1990,59:253-260.
[46] WallisDeVries, M F, Daleboudt C. Foraging strategy of cattle in patchy grassland[J].Oecologia,1994,100:98-106.
[47] De Knegt H J, Hengeveld G M, van Langevelde F, et al. Patch density determines movementpatterns and foraging efficiency of large herbivores[J]. Behav Ecol,2007,18:1065-1072.
[48] Searle K R, Hobbs N T, Shipley L A. Should I stay or should I go? patch departure decisionsby herbivores at multiple scales[J]. Oikos,2005,111:417-424.
[49] Hobbs N T. Responses of large herbivores to spatial heterogeneity in ecosystems[C]. In: JungH G, Fahey G C, eds. Nutritional Ecology of Herbivores. Proc5th Inter Symp Nutr Herb.Amer Soc Anim Sci,1999.97-129.
[50] Hewitson L, Dumont B, Gordon I J. Response of foraging sheep to variability in the spatialdistribution of resources[J]. Anim Behav,2005,69:1069-1076.
[51] Gillen R L, Krueger W C, Miller R F. Cattle distribution on mountain rangeland innortheastern Oregon[J]. J Range Manage,1984,37:549-553.
[52] Burritt E A, Provenza F D. Lambs form preferences for non-nutritive flavors paired withglucose[J]. J Anim Sci,1992,70:1133-1136.
[53] Ginane C, Duncan A J, Young S A, et al. Herbivore diet selection in response to simulatedvariation in nutrient rewards and plant secondary compounds[J]. Anim Behav,2005,69:541-550.
[54] Cooper S M, Owen-Smith N. Effects of plant spinescence on large mammalian herbivores[J].Oecologia,1986,68:446-455.
[55] Cooper S M, Owen-Smith N, Bryant J P. Foliage acceptability to browsing ruminants inrelation to seasonal changes in the leaf chemistry of woody plants in a South Africansavanna[J]. Oecologia,1988,75:336-342.
[56] O'Reagan P J. Plant structure and the acceptability of different grasses to sheep[J]. J RangeMange,1993,46:232-236.
[57] Unsicker S B, Oswald A, K hler G, et al. Complementarity effects through dietary mixingenhance the performance of a generalist insect herbivore[J]. Oecologia,2008,156:313-324.
[58] Jamieson W, Hodgson J. The effects of variation in sward characteristics upon the ingestivebehaviour and herbage intake of calves and lambs under a continuous stockingmanagement[J]. Grass Forage Sci,1979,34:273-282.
[59] Yearsley J, Tolkamp B J, Illius A W. Theoretical developments in the study and prediction offood intake[J]. P Nutr Soc,2001,60(1):145-156.
[60] Early D M, Provenza F D. Food flavor and nutritional characteristics alter dynamics of foodpreference in lambs[J]. J Anim Sci,1998,76:728-734.
[61] Freeland W, Janzen D. Strategies in herbivory by mammals: The role of plant secondarycompounds[J]. Am Nat,1974,108:269-289.
[62] Burritt E A, Provenza F D. Role of toxins in intake of varied diets by sheep[J]. J Chem Ecol,2000,26:1991-2005.
[63] Marsh K J, Wallis I R, McLean S, et al. Conflicting demands on detoxification pathwaysinfluence how common brushtail possums choose their diets[J]. Ecology,2006,87:2103-2112.
[64] Wilmshurst J F, Fryxell J M, Colucci P E. What constrains daily intake in Thomson's gazelles?[J]. Ecology,1999,80:2338-2347.
[65] Baumont R, Prache S, Meuret M, et al. How forage characteristics influence behaviour andintake in small ruminants: a review[J]. Livest Prod Sci,2000,64:15-28.
[66] Faverdin P, Baumont R, Ingvartsen K L. Control and prediction of feed intake inruminants[C].In: Journet M, Grenet E, Farce M H, eds. Recent Developments in the Nutrition ofHerbivores. Proc4th Inter Symp Nutr Herb. Paris: INRA Editions,1995.95-120.
[67] Provenza F D, Villalba J J, Dziba L E, et al. Linking herbivore experience, varied diets, andplant biochemical diversity[J]. Small Ruminant Res,2003,49:257-274.
[68] Scott L L, Provenza F D. Variety of foods and flavors affects selection of foraging location bysheep[J]. Appl Anim Behav Sci,1998,61:113-122.
[69] Scott L L, Provenza F D. Lambs fed protein or energy imbalanced diets forage in locationsand on foods that rectify imbalances[J]. Appl Anim Behav Sci,2000,68:293-305.
[70] Bakker E, Ritchie M E, Olff H, et al. Herbivore impact on grassland plant diversity dependson habitat productivity and herbivore size[J]. Ecol Lett,2006,9:780-788.
[71] Provenza F D. Postingestive feedback as an elementary determinant of food preference andintake in ruminants[J]. J Range Mange,1995,48:2-17.
[72] Harmon J P, Hladilek E E, Hinton J L, et al. Herbivore response to vegetational diversity:spatial interaction of resources and natural enemies[J]. Popul Ecol,2003,45:75-81.
[73] Scherber C, Mwangi P N, Temperton V M, et al. Effects of plant diversity on invertebrateherbivory in experimental grassland[J]. Oecologia,2006,147:489-500.
[74] Wang L, Wang D L, Liu J S, et al. Diet selection variation of a large herbivore in a feedingexperiment with increasing species numbers and different plant functional groupcombinations[J]. Acta Oecologica,2011,37:263-268.
[75] Wang L, Wang D L, He Z B, et al. Mechanisms linking plant species richness to foraging of alarge herbivore. J Appl Ecol,2010,47:868-875.
[76] Wang L, Wang D L, Bai Y G, et al. Spatial distributions of multiple plant species affectherbivore foraging selectivity[J]. Oikos,2010,119:401-408.
[77] Dumont B, Carrère P, D'Hour P. Foraging in patchy grasslands: diet selection by sheep andcattle is affected by the abundance and spatial distribution of preferred species[J]. Anim. Res,2002,51:367-382.
[78] Hassall M, Tuck J M, Smith D B, et al. Effects of spatial heterogeneity on feeding behavior ofPorcellio scaber (Isopoda: Oniscidea)[J]. Eur J Soil Biol,2002,38:53-57.
[79] Lindroth R L, Batzli G O, Avildsen S I. Lespedeza phenolics and penstemon alkaloids: effecton digestion efficiencies and growth of voles[J]. J Chem Ecol,1986,12:713-728.
[80]刘国方.羊草群落物种多样性对绵羊采食行为的影响[D]：[硕士学位论文].长春：东北师范大学草地科学研究所，2007.
[81] Villalba J J, Provenza F D. Preference for flavored wheat straw by lambs conditioned withintraruminal administrations of sodium propionate[J]. J Anim Sci,1996,74:2362-2368.
[82] Villalba J J, Provenza F D. Polyethylene glycol influences selection of foraging location bysheep consuming quebracho tannin[J]. J Anim Sci,2002,80:1846-1851.
[83] Villalba J J, Provenza F D. Preference for flavored wheat straw by lambs conditioned withintraruminal infusions of acetate and propionate[J]. J Anim Sci,1997,75:2905-2914.
[84] Villalba J J, Provenza F D. Preference for wheat straw by lambs conditioned withintraruminal infusions of starch[J]. Br J Nutr,1997,77:287-297.
[85] Villalba J J, Provenza F D. Discriminating among novel foods: effects of energy provision onpreferences of lambs for poor-quality foods[J]. Appl Anim BehavSci,2000,66:87-106.
[86] Burritt E A, Provenza F D. Food aversion learning: conditioning lambs to avoid a palatableshrub (Cercocarpus montanus)[J]. J Anim Sci,1989,67:650-653.
[87] Villalba J J, Provenza F D. Nutrient-specific preferences by lambs conditioned withintraruminal infusions of starch, casein, and water[J]. J Anim Sci,1999,77:378-387.
[88] Villalba J J, Provenza F D. Preference for flavoured foods by lambs conditioned withintraruminal administration of nitrogen[J]. Br J Nutr,1997,78:545-561.
[89] Pyke G H. Optimal foraging theory: a critical review[J]. Ann Rev Ecol,1984,15:523-575.
[90] McArthur C, Robbins C T, Hagerman A E, et al. Diet selection by a ruminant generalistbrowser in relation to plant chemistry[J]. Can J Zool,1993,71:2236-2243.
[91] Laca E A, Distel R A, Criggs T C, et al. Field test of optimal foraging with cattle: themarginal value theorem successfully predicts patch selection and utilization[C]. Proc17th IntGrassl Congr,1993.709-710.
[92] Illius A W, Duncan P, Richard C, et al. Mechanisms of functional response and resourceexploitation in browsing roe deer[J]. J Anim Ecol,2002,71:723-734.
[93] Hobbs N T. Responses of large herbivores to spatial heterogeneity in ecosystems[C]. In: JungH G and Fahey G C, eds. Nutritional ecology of herbivores. Proc Vth Int Symp on thenutrition of herbivores. Am Soc Anim Sci,1999.97-129.
[94] ARC. Requirements for energy[M]. ARC, Nutrient Requirements of Farm Livestock, No.2Ruminants, ARC, London.1965.193-257.
[95] Belovsky G E, Slade J B. Insect herbivory accelerates nutrient cycling and increases plantproduction[J]. PNAS,2000,97:14412-14417.
[96] Hagele B F, Rowell-Rahier M. Dietary mixing in three generalist herbivores: nutrientcomplementation or toxin dilution[J]. Oecologia,1999,119:521-533.
[97] Provenza F D, Scott C B, Phy T S, et al. Preference of sheep for foods varying in flavors andnutrients[J]. J Anim Sci,1996,74:2355-2361.
[98] Hughes B O. Appetites for specific nutrients[M]. In: Boorman K N, Freeman B M, eds. FoodIntake Regulation in Poultry. Proc14th Poul Sci Symp Edinburgh. British Poultry Science,1979.141-169.
[99] Forbes J M, Mayes R W. Food choice[M]. In: Freer M, Dove H, eds. Sheep Nutrition. NewYork: CAB International.2002.59.
[100] Lindlof B, Lindstrom E S, Pehrson A. Nutrient content in relation to food preferred bymountain hare[J]. J Wildl Manag,1974,38:875-879.
[101] Klein D R. Winter food preferred learning of snowshoe hares in interior Alaska[J]. J WildlManag,1977,13:266-275.
[102] Pehrson A. Winter food consumption and digestibility in caged mountain hares[J]. J Mamm,1984,65:231-239.
[103] Provenza F D.Acquired aversions as the basis for varied diets of food preference and intakein ruminants[J]. J Anim Sci,1996,74:2010-2020.
[104] Landau S, Silanikove N, Nitsan Z, et al. Short-term changes in eating patterns explain theeffects of condensed tannins on feed intake in heifers[J]. Appl Anim Behav Sci,2000,69:199-213.
[105] Kronberg S L, Muntifering R B, Ayers E L, et al. Cattle avoidance of leafy spurge: A case ofconditioned aversion[J]. J Range Manage,1993,46:364-366.
[106] Newman J A, Parsons A J, Thornley H M, et al. Optimal diet selection by a generalistgrazing herbivore[J]. Funct Ecol,1995,9:255-268.
[107] Ungar E D, Noy-Meir I. Herbage intake in relation to availability and sward structure:grazing processes and optimal foraging[J]. J Appl Ecol,1988,25:1045-1062.
[108] Green R F. Stopping rules for optimal foragers[J]. Am Nat,1984,123:30-40.
[109] Iwasa Y, Higashi M, Yamamura N. Pre-distribution as a factor determining the choice ofoptimal foraging strategy[J]. Am Nat,1981,117:710-723.
[110] Simpson S J, Sibly R M, Lee K P, et al. Optimal foraging when regulating intake of multiplenutrients[J]. Anim Behav,2004,68:1299-1311.
[111]孙儒泳.动物生态学原理[M].北京：北京师范大学出版社,2001.257-259.
[112] WallisDeVries M F, Laca E A, Demment M W. The importance of scale of patchiness forselectivity in grazing herbivores[J], Oecologia,1998,121:355-363.
[113] Illius A W, Clark D A, Hodgson J. Discrimination and patch choice by sheep grazinggrass-clover swards[J]. J Anim Ecol,1992,61:183-194.
[114] Distel R A, Laca E A, Griggs T C, et al. Patch selection by cattle: Maximization of intakerate in horizontally heterogeneous pastures[J]. Appl Anim Behav Sci,1995,45:11-21.
[115] Fauchald P. Foraging in a hierarchical patch system[J]. Am Nat,1999,153:603-613.
[116] Stephens D W, Krebs J R. Foraging Theory[M]. Princeton: Princeton University Press,1986.
[117] Laca E, Demmen M. Foraging strategies of grazing animals[C]. In: Hodgson J, Illius A, eds.The Ecology and Management of Grazing Systems. Wallingford: CAB International,1996.137-158.
[118] Dumont B, Maillard J F, Petit M. The effect of the spatial distribution of plant species withinthe sward on the searching success of sheep when grazing[J]. Grass Forage Sci,2000,55:138-145.
[119] Edwards G R, Newman J A, Parsons A J, et al. Effects of the scale and spatial distribution ofthe food resource and animal state on diet selection: an example with sheep[J]. J Anim Ecol,1994,63:816-826.
[120] Searle K R, Hobbs N T, Shipley L A. Should I stay or should I go? patch departure decisionsby herbivores at multiple scales[J]. Oikos,2005,111:417-424.
[121] Edwards G R, Newman J A, Parsons A J. The use of spatial memory by grazing animals tolocate food patches in spatially heterogeneous environments: an example with sheep[J].Appl Anim Behav Sci,1996,50:147-160.
[122] Laca E A. Spatial memory and food searching mechanisms of cattle[J]. J Range Manage,1998,51:370-378.
[123] Johnson R A. Learning memory and foraging efficiency in two species of desertseed-harvester ants[J]. Ecology,1991,72:1408-1419.
[124] Olton D S. Spatial memory and food searching strategies[M]. In: Kamil A C, Sargent T D,eds. Foraging Behavior: Ecological, ethological and psychological approaches. GarlandSTPM Press,1981.333-354.
[125] Gillingham M P, Bunnell F L. Effects of learning on food selection and searching behaviorof deer[J]. Can J Zool,1989,67:24-32.
[126] Benhamon S. Spatial memory and searching efficiency[J]. Anim Behav,1994,47:1423-1433.
[127] Huang Y, Wang L, Wang D L, et al. The effect of plant spatial pattern within a patch onforaging selectivity of grazing sheep[J]. Landscape Ecol,2012,27:911-919.
[128] Wang L, Wang D L, Bai Y G, et al. Spatially complex neighboring relationships amonggrassland plant species as an effective mechanism of defense against herbivory[J].Oecologia,2010,164(1):193-200.
[129] Mayland H F, Shewmaker G E. Plant attributes that affect livestock selection and intake[M].In: Launchbaugh K L, Sanders K D, Mosley J C, eds. Grazing Behavior of Livestock andWildlife. Moscow: University of Idaho Moscow.1999.
[130] Gross J E, Zank C, Hobbs N T, et al. Movement rules for herbivores in spatiallyheterogeneous environments: responses to small scale pattern[J]. Landscape Ecol,1995,10(4):209-217.
[131] Garcia F, Carre`re P, Soussana J F, et al. Characterisation by fractal analysis of foragingpathsof ewes grazing heterogeneous swards[J]. Appl Anim Behav Sci.2005,93:19-37.
[132] Fauchald P, Tveraa T. Using First-Passage Time in the analysis of area-restricted search andhabitat selection[J]. Ecology,2003,84:282-288.
[133] Reagain P O. Foraging strategies on rangeland: effect on intake and animal performance[J].Proceedings of the XIX International Grassland Congress,2001,277-282.
[134] Johnson C J, Parker K L, Heard D C, et al. Movement parameters of ungulates andscale-specific responses to the environment[J]. J Anim Ecol,2002,71:225-235.
[135] Bailey H, Thompson P. Quantitative analysis ofbottlenose dolphin movement patterns andtheir relationship with foraging[J]. J Anim Ecol,2006,75:456-465.
[136] Shipley L A, Spalinger D E, Gross J E, et al. The dynamics and scaling of foraging velocityand encounter rate in mammalian herbivores[J]. Funct Ecol.1996,10:234-244.
[137] Bartumeus F, Da Luz M G E, Viswanathan G M, et al. Animal Search Strategies: AQuantitative Random-Walk Analysis[J]. Ecology,2005,869(11):3078-3087.
[138] Fritz H, Sa d S, Weimerskirch, H. Evidence for scale-dependent hierarchical adjustments ofmovement patterns in long range foraging animals. Proceedings of the Royal Society,London (B).2003,270:1143-1148.
[139] Nams V O. Using animal movement paths to measure response to spatial scale[J]. Oecologia,2005,143:179-188.
[140] Frair J L, Merrill E H, Visscher D R, et al. Scales of movement by elk (Cervuselaphus) inresponse to heterogeneity in forage resourcesand predation risk[J]. Landscape Ecol.2005,20:273-287.
[141] Cain M L. Random search by herbivorous insects: a simulation model[J]. Ecology,1985,66:876-888.
[142] Gross J E, Zank C, Hobbs N T, et al. Movement rules for herbivores in spatiallyheterogeneous environments: responses to small scale pattern[J]. Landscape Ecol,1995,10:209-217.
[143] Howery L D, Bailey D W, Ruyle G B, et al. Cattle use visual cues to track food locations[J].Appl Anim Behav Sci,2000,67:1-14.
[144] Bazely D R. Rules and cues used by sheep foraging in monocultures[M]. In: Hughes R N,eds. Behavioural Mechanisms of Food Selection. Berlin: Spring-Verlag,1990.344-366.
[145] Edwards G R, Newman J A, Parsons A J, et al. Use of cues by grazing animals to locatefoodpatches: an example with sheep[J]. Appl Anim Behav Sci,1997,51:59-68.
[146] Bergvall U A, Rautio P, Kesti K, et al. Associational effects of plant defences in relation towithin-and between-patch food choice by a mammalian herbivore: Neighbour contrastsusceptibility and defence[J]. Oecologia,2006,147:253-260.
[147] Oom S P, Hester A J, Elston D A, et al. Spatial interaction models: From human geographyto plant-herhivore interactions[J]. Oikos,2002,98:65-74.
[148] Palmer S C F, Hester A J, Elston D A, et al. The perils of having tasty neighbors: Grazingimpacts of large herbivores at vegetation boundaries[J]. Ecology,2003,84:2877-2890.
[149] Bee J N, Tanentzap A J, Lee W G, et al. The benefits of being in a bad neighbourhood: Plantcommunity composition influences red deer foraging decisions[J]. Oikos,2009,118:18-24.
[150] Callaway R M, Kikodze D, Chiboshvili M, et al. Unpalatable plants protect neighbors fromgrazing and increase plant community diversity[J]. Ecology,2005,86:1856-1862.
[151] Eskelinen A. Herbivore and neighbour effects on tundra plants depend on species identity,nutrient availability and local environmental conditions[J]. J Ecol,2008,96:155-165.
[152] Miller A M, McArthur C, Smethurst P J. Spatial scale and opportunities for choice influencebrowsing and associational refuges of focal plants[J]. J Anim Ecol,2009,78:1134-1142.
[153] Illius A W, Gordon I J, Elston D A, et al. Diet selection in goats: A test of intake-ratemaximization[J]. Ecology,1999,80:1008-1018.
[154] Wiggins N L, McArthur C, Davies N W. Diet switching in a generalist mammalian folivore:Fundamental to maximizing intake[J]. Oecologia,2006,147:650-657.
[155] Boone R B. Effects of fragmentation on cattle in Africansavannas under variableprecipitation[J]. Landscape Ecol,2007,22:1355-1369.
[156] Clarke J L, Welch D, Gordon I J. The influence of vegetation pattern on the grazing ofheather moorland by red deer and sheep. I. The location of animals on grass/heathermosaics[J]. J Appl Ecol,1995,32:166-176.
[157] Ward D, Saltz D. Foraging at different spatial scales: Dorcas gazelles foraging for lilies inthe NegevDesert[J]. Ecology,1994,75:48-58.
[158] Harata M, Kanemaru E, Tobisa M. Patch choice by cattle grazing tropical grass swards: apreliminary study[J]. Appl Anim Behav Sci,2006,97:134-144.
[159] Kohler F, Gillet F, Reust S, et al. Buttler A Spatial and seasonal patterns of cattle habitat usein a mountain wooded pasture[J]. Landscape Ecol,2006,21:281-295.
[160] Bergman M, Iason G R, Hester A J. Feeding patterns byroe deer and rabbits on pine, willowand birch in relation tospatial arrangement[J]. Oikos,2005,109:513-520.
[161] Newman J A. Herbivory[C]. In: Stephens D W, Brown J S, Ydenberg R C, eds. Foraging:behaviour and ecology. Chicago: University of Chicago Press,2007.175-220.
[162] Benhamou S. Spatial memory and searching efficiency[J]. Anim Behav,1994,47:1423-1433.
[163] Benhamou S. Efficiency of area-concentrated searching behaviour in a continuous patchyenvironment[J]. J Theor Biol,1992,159:67-81.
[164] Dumont B, Petit M. Spatial memory of sheep at pasture[J]. Appl Anim Behav Sci,1998,60:43-53
[165] Bergvall U A, Rautio P, Sirn H, et al. The effect of spatial scale on plant associationaldefences against mammalian herbivores[J]. Ecoscience,2008,15:343-348.
[166] Hay M E. Associational plant defenses and the maintenance of species diversity: Turningcompetitors into accomplices[J]. Am Nat,1986,128:617-641.
[167]王德利.植物与草食动物之间的协同适应及进化[J].生态学报,2004,24(11):2641-2648.
[168]王德利，高莹.竞争进化与协同进化[J].生态学杂志,2005,24(10):1182-1186.
[169] Palmer S C F, Hester A J, Elston D A, et al. The perils of having tasty neighbors: grazingimpacts of large herbivores at vegetation boundaries[J]. Ecology,2003,84:2877-2890.
[170] Bee J N, Tanentzap A J, Lee W G, et al, The benefits of being in a bad neighbourhood: Plantcommunity composition influences red deer foraging decisions[J]. Oikos,2009,118:18-24.
[171] Miller A M, McArthur C, Smethurst P J. Effects of within-patch characteristics on thevulnerability of a plant to herbivory[J]. Oikos,2007,116:41-52.
[172] Owens M K, Karen L, Launchbaugh K L, et al. Pasture characteristics affecting spatialdistribution of utilization by cattle in mixed brush communities[J]. J Range Manage,1991,44:118-123.
[173] Pinaud A, Weimerskirch H. At-sea distribution and scale-dependent foraging behaviour ofpetrels and albatrosses: a comparative study[J]. J Anim Ecol,2007,76:9-19.
[174] Giulio M D, Edwards P J. The influence of host plant diversity and food quality on larvalsurvival of plant feeding heteropteranbugs[J]. Ecol Entomol,2003,28:51-57.
[175] Specht J, Scherber C, Unsicker S B, et al. Diversity and beyond: Plant functional identitydetermines herbivore performance[J]. J Anim Ecol,2008,77:1047-1055.
[176] Milchunas D G, Noy-Meir I. Grazing refuges, external avoidance of herbivory and plantdiversity[J]. Oikos,2002,99:113-130.
[177] Agrawal A A, Lau J A, Hamb ck P A. Community heterogeneity and the evolution ofinteractions between plants and insect herbivores[J]. Q Rev Biol,2006,81:349-376.
[178] Provenza F D, Pfister J A, Cheney C D. Mechanisms of learning in diet selection withreference to phyto toxicosis in herbivores[J]. J Range Mange,1992,45:36-45.
[179] Marion G, Swain D L, Hutchings M R. Understanding foraging behavior in spatiallyheterogeneous environments[J]. J Theor Biol,2005,232:127-142.
[180] Chapman D F, Parsons A J, Cosgrove G P, et al. Impacts of spatial patterns in pasture onanimal grazing behavior, intake, and performance[J]. Crop Sci,2007,47(1):399-415.
[181] Wang D L, Han G D, Bai Y G. Interactions between foraging behavior of herbivores andgrassland resources in the eastern Eurasian steppes[C]. In: Mcgilloway D A, ed. Grassland:a Global Resource. Netherlands: Wageningen Academic Press,2005.97-110.
[182] Berteaux D, Crete M, Huot J, et al. Food choice by white-tailed deer in relation to proteinand energy content of the diet: a field experiment[J]. Oecologia,1998,115:84-92.
[183] Kyriazakis I, Oldham J D. Diet selection in sheep: the ability of growing lambs to select adiet that meets their crude protein (nitrogen×6.25) requirements[J]. Br J Nutr,1993,69:617-629.
[184] Gomez J M, Zamora R. Thorns as induced mechanical defense in a long-lived shrub(Hormathophyllaspinosa, Cruciferae)[J]. Ecology,2002,83(4):885-890..
[2] Crawley M J. Herbivory: The Dynamics of Animal-Plant Interactions[M]. Oxford, UK:Blackwell Scientific Publications,1983.
[3] Atsatt P R, O'Dowd D J. Plant defense guilds[J]. Science,1976,193:24-29.
[4] Adler P B, Raff D A, Lauenroth W K. The effect of grazing on the spatial heterogeneity ofvegetation[J]. Oecologia,2001,128:465-479.
[5] Griffin J N, Jenkins S R, Gamfeldt L, et al. Spatial heterogeneity increases the importance ofspecies richness foran ecosystem process [J]. Oikos,2009,118:1335-1342.
[6] Li H, Reynolds J F. On definition and quantification of heterogeneity[J]. Oikos,1995,73:280-284.
[7]张金屯.数量生态学[M].北京：科学出版社，2004.
[8] Baraza E, Zamora R, Ho′dar J A. Conditional outcomes in plant-herbivore interactions:Neighbours matter[J]. Oikos,2006,113:148-156.
[9] WallisDeVries M F. Effects of resource distribution patterns on ungulate foraging behaviour:a modellingapproach[J]. Forest Ecol Manage,1996,88:167-177.
[10] Forbes J M. Consequences of feeding for future feeding[J]. Comp Biochem Physiol,2001,128:461-468.
[11] Wilmshurst J F, Fryxell JM, Hudsonb R J. Forage quality and patch choice by wapiti(Cervuselaphus)[J]. Behav Ecol,1995,6:209-217.
[12] Fisher D S. A review of a few key factors regulating voluntary feed intake in ruminants[J].Crop Science,2002,42(5):1651-1655.
[13] Charnov E L. Optimal foraging, the marginal value theorem[J]. Theo Popul Biol,1976,9:129-136.
[14] Parsons A J, Dumont B. Spatial heterogeneity and grazing processes[J]. Anim. Res,2003,52:161-180.
[15] Illius A W, Gordon I J, Elston D A, et al. Diet selection in goats: A test of intake-ratemaximization[J]. Ecology,1999,80(3):1008-1018.
[16] Schoener T. Theory of feeding strategies[J]. Annu Rev Ecol Syst,1971,2:369-404.
[17] Proulx M, Mazumder A. Reversal of grazing impact on plant species richness in nutrient-poorvs. nutrient-rich ecosystems[J]. Ecology,1998,79:2581-2592.
[18] Milchunas D G, Lauenroth W K. Quantitative effects of grazing on vegetation and soils over aglobal range of environments[J]. Ecol Monogr,1993,63:327-366.
[19] Olff H, Ritchie M E. Effects of herbivores on grassland plant diversity[J]. Trends Ecol Evol,1998,13:261-265.
[20]刘颖，王德利，王旭，等.放牧强度对羊草草地植被特征的影响[J].草业学报,2002,11(2):22-28.
[21] Frank D A. The interactive effects of grazing ungulates and aboveground production ongrassland diversity[J]. Oecologia,2005,143:629-634.
[22]刘鞠善.大型草食动物采食对植物多样性与空间格局的响应及行为适应机制[D]：[博士学位论文].长春：东北师范大学草地科学研究所，2011.
[23] Nolte D L, Mason J R, Lewis S L. Tolerance of bitter compounds by an herbivore,Caviaporcellus[J]. J Chem Ecol,1994,20:303-308.
[24] Molan A P, Duncan A, Barry T N, et al. Effects of condensed tannins and sesquiterpenelactones extracted from chicory on the viability of deer lungworm larvae[J]. Proc NewZealand Soc Anim Prod,2000,60:26-29.
[25] Molan A, Waghorn G C, Min B R, et al. The effect of condensed tannins from seven herbageson Trichostrongylus colubriformis larval migration in vitro[J]. Folia Parasit,2000,47:39-44.
[26] Thomes D W, Sanson C, Bergeron J M. Metabolic cost associated with the ingestion of planphenolics by Microtus pennsylvanicus[J]. J Mammal,1988,69:512-515.
[27] Athanasiadou S, Kyriazakis I. Plant secondary metabolites: antiparasitic effects and their rolein ruminant production systems[J]. P Nutr Soc,2004,63:631-639.
[28] Feeny P. Seasonal changes in oak leaf tannins and nutrients as a cause of spring feeding bywinter moth caterpillars[J]. Ecology,1970,51:565-581.
[29] Wang J, Provenza F D. Dynamics of preference by sheep offered foods varying in flavors,nutrients, and a toxin[J]. J Chem Ecol,1997,23:275-288.
[30] Dearing D M, Cork S. Role of detoxification of plant secondary compounds on diet breadthin a mammalian herbivore (Trichosurus vulpecula)[J]. J Chem Ecol,1999,25:1205-1219.
[31] Wiggins N L, McArthur C, McLean S, et al. Effects of two plant secondary metabolites,cineole and gallic acid, on nightly feeding patterns of the common brushtail possum[J]. JChem Ecol,2003,29:1423-1440.
[32] Lindroth R L, Batzli G. Plant phenolics as chemical defences: effects of natural phenolics onsurvival and growth of prairie voles (Microtus ochragaster)[J]. J Chem Ecol,1984,10:229-244.
[33]滕星，王德利，程志茹，等.不同放牧强度下绵羊采食方式的变化特征[J].草业学报,2004,13(2):67-72.
[34]巴雷，王德利，高莹.松嫩平原优势种羊草与其主要伴生种芦苇空间分布格局分析[J].草业学报,2005,14(5):111-116.
[35]巴雷，王德利，刘颖，等.羊草与其主要伴生种竞争与共存的格局分析[J].应用生态学报,2002,13(1):50-54.
[36]王岭，王德利.放牧家畜食性选择机制研究进展[J].应用生态学报,2007,18(1):205-211.
[37] Parsons A J, Newman J A, Penning P D, et al. Diet preference of sheep: effects of recent diet,physiological state and species abundance[J]. J Anim Ecol,1994,63:456-478.
[38] Senft R L, Coughenour M B, Bailey D W, et al. Large herbivore foraging and ecologicalhierarchies[J]. Bioscience,1987,37:789-795.
[39] Bailey D W, Gross J E, Laca E A, et al. Mechanisms that result in large herbivore grazingdistribution patterns[J]. J Range Manage,1996,49(5):386-400.
[40]王德利，程志茹.放牧家畜的采食行为理论研究[J].草业科学,2002,5（增刊）:114-121.
[41] Shipley L A, Gross J E, Spalinger D E, et al. The scaling of intake rate in mammalianherbivores[J]. Am Nat,1994,143:1055-1082.
[42] Fortin D, Fryxell J M, Pilote R. The temporal scale of foraging decisions in bison[J]. Ecology,2002,83:970-982.
[43] Lima S L, Zollner P A. Towards a behavioral ecology of ecological landscapes[J]. TrendsEcol Evol,1996,11:131-135.
[44] Illius A W, Clark D A, Hodgson J. Discrimination and patch choice by sheep grazinggrass-clover swards[J]. J Anim Ecol,1992,61:183-194.
[45] Kotliar N B, Wiens J A. Multiple scales of patchiness and patch structure: a hierarchicalframework for the study of heterogeneity[J]. Oikos,1990,59:253-260.
[46] WallisDeVries, M F, Daleboudt C. Foraging strategy of cattle in patchy grassland[J].Oecologia,1994,100:98-106.
[47] De Knegt H J, Hengeveld G M, van Langevelde F, et al. Patch density determines movementpatterns and foraging efficiency of large herbivores[J]. Behav Ecol,2007,18:1065-1072.
[48] Searle K R, Hobbs N T, Shipley L A. Should I stay or should I go? patch departure decisionsby herbivores at multiple scales[J]. Oikos,2005,111:417-424.
[49] Hobbs N T. Responses of large herbivores to spatial heterogeneity in ecosystems[C]. In: JungH G, Fahey G C, eds. Nutritional Ecology of Herbivores. Proc5th Inter Symp Nutr Herb.Amer Soc Anim Sci,1999.97-129.
[50] Hewitson L, Dumont B, Gordon I J. Response of foraging sheep to variability in the spatialdistribution of resources[J]. Anim Behav,2005,69:1069-1076.
[51] Gillen R L, Krueger W C, Miller R F. Cattle distribution on mountain rangeland innortheastern Oregon[J]. J Range Manage,1984,37:549-553.
[52] Burritt E A, Provenza F D. Lambs form preferences for non-nutritive flavors paired withglucose[J]. J Anim Sci,1992,70:1133-1136.
[53] Ginane C, Duncan A J, Young S A, et al. Herbivore diet selection in response to simulatedvariation in nutrient rewards and plant secondary compounds[J]. Anim Behav,2005,69:541-550.
[54] Cooper S M, Owen-Smith N. Effects of plant spinescence on large mammalian herbivores[J].Oecologia,1986,68:446-455.
[55] Cooper S M, Owen-Smith N, Bryant J P. Foliage acceptability to browsing ruminants inrelation to seasonal changes in the leaf chemistry of woody plants in a South Africansavanna[J]. Oecologia,1988,75:336-342.
[56] O'Reagan P J. Plant structure and the acceptability of different grasses to sheep[J]. J RangeMange,1993,46:232-236.
[57] Unsicker S B, Oswald A, K hler G, et al. Complementarity effects through dietary mixingenhance the performance of a generalist insect herbivore[J]. Oecologia,2008,156:313-324.
[58] Jamieson W, Hodgson J. The effects of variation in sward characteristics upon the ingestivebehaviour and herbage intake of calves and lambs under a continuous stockingmanagement[J]. Grass Forage Sci,1979,34:273-282.
[59] Yearsley J, Tolkamp B J, Illius A W. Theoretical developments in the study and prediction offood intake[J]. P Nutr Soc,2001,60(1):145-156.
[60] Early D M, Provenza F D. Food flavor and nutritional characteristics alter dynamics of foodpreference in lambs[J]. J Anim Sci,1998,76:728-734.
[61] Freeland W, Janzen D. Strategies in herbivory by mammals: The role of plant secondarycompounds[J]. Am Nat,1974,108:269-289.
[62] Burritt E A, Provenza F D. Role of toxins in intake of varied diets by sheep[J]. J Chem Ecol,2000,26:1991-2005.
[63] Marsh K J, Wallis I R, McLean S, et al. Conflicting demands on detoxification pathwaysinfluence how common brushtail possums choose their diets[J]. Ecology,2006,87:2103-2112.
[64] Wilmshurst J F, Fryxell J M, Colucci P E. What constrains daily intake in Thomson's gazelles?[J]. Ecology,1999,80:2338-2347.
[65] Baumont R, Prache S, Meuret M, et al. How forage characteristics influence behaviour andintake in small ruminants: a review[J]. Livest Prod Sci,2000,64:15-28.
[66] Faverdin P, Baumont R, Ingvartsen K L. Control and prediction of feed intake inruminants[C].In: Journet M, Grenet E, Farce M H, eds. Recent Developments in the Nutrition ofHerbivores. Proc4th Inter Symp Nutr Herb. Paris: INRA Editions,1995.95-120.
[67] Provenza F D, Villalba J J, Dziba L E, et al. Linking herbivore experience, varied diets, andplant biochemical diversity[J]. Small Ruminant Res,2003,49:257-274.
[68] Scott L L, Provenza F D. Variety of foods and flavors affects selection of foraging location bysheep[J]. Appl Anim Behav Sci,1998,61:113-122.
[69] Scott L L, Provenza F D. Lambs fed protein or energy imbalanced diets forage in locationsand on foods that rectify imbalances[J]. Appl Anim Behav Sci,2000,68:293-305.
[70] Bakker E, Ritchie M E, Olff H, et al. Herbivore impact on grassland plant diversity dependson habitat productivity and herbivore size[J]. Ecol Lett,2006,9:780-788.
[71] Provenza F D. Postingestive feedback as an elementary determinant of food preference andintake in ruminants[J]. J Range Mange,1995,48:2-17.
[72] Harmon J P, Hladilek E E, Hinton J L, et al. Herbivore response to vegetational diversity:spatial interaction of resources and natural enemies[J]. Popul Ecol,2003,45:75-81.
[73] Scherber C, Mwangi P N, Temperton V M, et al. Effects of plant diversity on invertebrateherbivory in experimental grassland[J]. Oecologia,2006,147:489-500.
[74] Wang L, Wang D L, Liu J S, et al. Diet selection variation of a large herbivore in a feedingexperiment with increasing species numbers and different plant functional groupcombinations[J]. Acta Oecologica,2011,37:263-268.
[75] Wang L, Wang D L, He Z B, et al. Mechanisms linking plant species richness to foraging of alarge herbivore. J Appl Ecol,2010,47:868-875.
[76] Wang L, Wang D L, Bai Y G, et al. Spatial distributions of multiple plant species affectherbivore foraging selectivity[J]. Oikos,2010,119:401-408.
[77] Dumont B, Carrère P, D'Hour P. Foraging in patchy grasslands: diet selection by sheep andcattle is affected by the abundance and spatial distribution of preferred species[J]. Anim. Res,2002,51:367-382.
[78] Hassall M, Tuck J M, Smith D B, et al. Effects of spatial heterogeneity on feeding behavior ofPorcellio scaber (Isopoda: Oniscidea)[J]. Eur J Soil Biol,2002,38:53-57.
[79] Lindroth R L, Batzli G O, Avildsen S I. Lespedeza phenolics and penstemon alkaloids: effecton digestion efficiencies and growth of voles[J]. J Chem Ecol,1986,12:713-728.
[80]刘国方.羊草群落物种多样性对绵羊采食行为的影响[D]：[硕士学位论文].长春：东北师范大学草地科学研究所，2007.
[81] Villalba J J, Provenza F D. Preference for flavored wheat straw by lambs conditioned withintraruminal administrations of sodium propionate[J]. J Anim Sci,1996,74:2362-2368.
[82] Villalba J J, Provenza F D. Polyethylene glycol influences selection of foraging location bysheep consuming quebracho tannin[J]. J Anim Sci,2002,80:1846-1851.
[83] Villalba J J, Provenza F D. Preference for flavored wheat straw by lambs conditioned withintraruminal infusions of acetate and propionate[J]. J Anim Sci,1997,75:2905-2914.
[84] Villalba J J, Provenza F D. Preference for wheat straw by lambs conditioned withintraruminal infusions of starch[J]. Br J Nutr,1997,77:287-297.
[85] Villalba J J, Provenza F D. Discriminating among novel foods: effects of energy provision onpreferences of lambs for poor-quality foods[J]. Appl Anim BehavSci,2000,66:87-106.
[86] Burritt E A, Provenza F D. Food aversion learning: conditioning lambs to avoid a palatableshrub (Cercocarpus montanus)[J]. J Anim Sci,1989,67:650-653.
[87] Villalba J J, Provenza F D. Nutrient-specific preferences by lambs conditioned withintraruminal infusions of starch, casein, and water[J]. J Anim Sci,1999,77:378-387.
[88] Villalba J J, Provenza F D. Preference for flavoured foods by lambs conditioned withintraruminal administration of nitrogen[J]. Br J Nutr,1997,78:545-561.
[89] Pyke G H. Optimal foraging theory: a critical review[J]. Ann Rev Ecol,1984,15:523-575.
[90] McArthur C, Robbins C T, Hagerman A E, et al. Diet selection by a ruminant generalistbrowser in relation to plant chemistry[J]. Can J Zool,1993,71:2236-2243.
[91] Laca E A, Distel R A, Criggs T C, et al. Field test of optimal foraging with cattle: themarginal value theorem successfully predicts patch selection and utilization[C]. Proc17th IntGrassl Congr,1993.709-710.
[92] Illius A W, Duncan P, Richard C, et al. Mechanisms of functional response and resourceexploitation in browsing roe deer[J]. J Anim Ecol,2002,71:723-734.
[93] Hobbs N T. Responses of large herbivores to spatial heterogeneity in ecosystems[C]. In: JungH G and Fahey G C, eds. Nutritional ecology of herbivores. Proc Vth Int Symp on thenutrition of herbivores. Am Soc Anim Sci,1999.97-129.
[94] ARC. Requirements for energy[M]. ARC, Nutrient Requirements of Farm Livestock, No.2Ruminants, ARC, London.1965.193-257.
[95] Belovsky G E, Slade J B. Insect herbivory accelerates nutrient cycling and increases plantproduction[J]. PNAS,2000,97:14412-14417.
[96] Hagele B F, Rowell-Rahier M. Dietary mixing in three generalist herbivores: nutrientcomplementation or toxin dilution[J]. Oecologia,1999,119:521-533.
[97] Provenza F D, Scott C B, Phy T S, et al. Preference of sheep for foods varying in flavors andnutrients[J]. J Anim Sci,1996,74:2355-2361.
[98] Hughes B O. Appetites for specific nutrients[M]. In: Boorman K N, Freeman B M, eds. FoodIntake Regulation in Poultry. Proc14th Poul Sci Symp Edinburgh. British Poultry Science,1979.141-169.
[99] Forbes J M, Mayes R W. Food choice[M]. In: Freer M, Dove H, eds. Sheep Nutrition. NewYork: CAB International.2002.59.
[100] Lindlof B, Lindstrom E S, Pehrson A. Nutrient content in relation to food preferred bymountain hare[J]. J Wildl Manag,1974,38:875-879.
[101] Klein D R. Winter food preferred learning of snowshoe hares in interior Alaska[J]. J WildlManag,1977,13:266-275.
[102] Pehrson A. Winter food consumption and digestibility in caged mountain hares[J]. J Mamm,1984,65:231-239.
[103] Provenza F D.Acquired aversions as the basis for varied diets of food preference and intakein ruminants[J]. J Anim Sci,1996,74:2010-2020.
[104] Landau S, Silanikove N, Nitsan Z, et al. Short-term changes in eating patterns explain theeffects of condensed tannins on feed intake in heifers[J]. Appl Anim Behav Sci,2000,69:199-213.
[105] Kronberg S L, Muntifering R B, Ayers E L, et al. Cattle avoidance of leafy spurge: A case ofconditioned aversion[J]. J Range Manage,1993,46:364-366.
[106] Newman J A, Parsons A J, Thornley H M, et al. Optimal diet selection by a generalistgrazing herbivore[J]. Funct Ecol,1995,9:255-268.
[107] Ungar E D, Noy-Meir I. Herbage intake in relation to availability and sward structure:grazing processes and optimal foraging[J]. J Appl Ecol,1988,25:1045-1062.
[108] Green R F. Stopping rules for optimal foragers[J]. Am Nat,1984,123:30-40.
[109] Iwasa Y, Higashi M, Yamamura N. Pre-distribution as a factor determining the choice ofoptimal foraging strategy[J]. Am Nat,1981,117:710-723.
[110] Simpson S J, Sibly R M, Lee K P, et al. Optimal foraging when regulating intake of multiplenutrients[J]. Anim Behav,2004,68:1299-1311.
[111]孙儒泳.动物生态学原理[M].北京：北京师范大学出版社,2001.257-259.
[112] WallisDeVries M F, Laca E A, Demment M W. The importance of scale of patchiness forselectivity in grazing herbivores[J], Oecologia,1998,121:355-363.
[113] Illius A W, Clark D A, Hodgson J. Discrimination and patch choice by sheep grazinggrass-clover swards[J]. J Anim Ecol,1992,61:183-194.
[114] Distel R A, Laca E A, Griggs T C, et al. Patch selection by cattle: Maximization of intakerate in horizontally heterogeneous pastures[J]. Appl Anim Behav Sci,1995,45:11-21.
[115] Fauchald P. Foraging in a hierarchical patch system[J]. Am Nat,1999,153:603-613.
[116] Stephens D W, Krebs J R. Foraging Theory[M]. Princeton: Princeton University Press,1986.
[117] Laca E, Demmen M. Foraging strategies of grazing animals[C]. In: Hodgson J, Illius A, eds.The Ecology and Management of Grazing Systems. Wallingford: CAB International,1996.137-158.
[118] Dumont B, Maillard J F, Petit M. The effect of the spatial distribution of plant species withinthe sward on the searching success of sheep when grazing[J]. Grass Forage Sci,2000,55:138-145.
[119] Edwards G R, Newman J A, Parsons A J, et al. Effects of the scale and spatial distribution ofthe food resource and animal state on diet selection: an example with sheep[J]. J Anim Ecol,1994,63:816-826.
[120] Searle K R, Hobbs N T, Shipley L A. Should I stay or should I go? patch departure decisionsby herbivores at multiple scales[J]. Oikos,2005,111:417-424.
[121] Edwards G R, Newman J A, Parsons A J. The use of spatial memory by grazing animals tolocate food patches in spatially heterogeneous environments: an example with sheep[J].Appl Anim Behav Sci,1996,50:147-160.
[122] Laca E A. Spatial memory and food searching mechanisms of cattle[J]. J Range Manage,1998,51:370-378.
[123] Johnson R A. Learning memory and foraging efficiency in two species of desertseed-harvester ants[J]. Ecology,1991,72:1408-1419.
[124] Olton D S. Spatial memory and food searching strategies[M]. In: Kamil A C, Sargent T D,eds. Foraging Behavior: Ecological, ethological and psychological approaches. GarlandSTPM Press,1981.333-354.
[125] Gillingham M P, Bunnell F L. Effects of learning on food selection and searching behaviorof deer[J]. Can J Zool,1989,67:24-32.
[126] Benhamon S. Spatial memory and searching efficiency[J]. Anim Behav,1994,47:1423-1433.
[127] Huang Y, Wang L, Wang D L, et al. The effect of plant spatial pattern within a patch onforaging selectivity of grazing sheep[J]. Landscape Ecol,2012,27:911-919.
[128] Wang L, Wang D L, Bai Y G, et al. Spatially complex neighboring relationships amonggrassland plant species as an effective mechanism of defense against herbivory[J].Oecologia,2010,164(1):193-200.
[129] Mayland H F, Shewmaker G E. Plant attributes that affect livestock selection and intake[M].In: Launchbaugh K L, Sanders K D, Mosley J C, eds. Grazing Behavior of Livestock andWildlife. Moscow: University of Idaho Moscow.1999.
[130] Gross J E, Zank C, Hobbs N T, et al. Movement rules for herbivores in spatiallyheterogeneous environments: responses to small scale pattern[J]. Landscape Ecol,1995,10(4):209-217.
[131] Garcia F, Carre`re P, Soussana J F, et al. Characterisation by fractal analysis of foragingpathsof ewes grazing heterogeneous swards[J]. Appl Anim Behav Sci.2005,93:19-37.
[132] Fauchald P, Tveraa T. Using First-Passage Time in the analysis of area-restricted search andhabitat selection[J]. Ecology,2003,84:282-288.
[133] Reagain P O. Foraging strategies on rangeland: effect on intake and animal performance[J].Proceedings of the XIX International Grassland Congress,2001,277-282.
[134] Johnson C J, Parker K L, Heard D C, et al. Movement parameters of ungulates andscale-specific responses to the environment[J]. J Anim Ecol,2002,71:225-235.
[135] Bailey H, Thompson P. Quantitative analysis ofbottlenose dolphin movement patterns andtheir relationship with foraging[J]. J Anim Ecol,2006,75:456-465.
[136] Shipley L A, Spalinger D E, Gross J E, et al. The dynamics and scaling of foraging velocityand encounter rate in mammalian herbivores[J]. Funct Ecol.1996,10:234-244.
[137] Bartumeus F, Da Luz M G E, Viswanathan G M, et al. Animal Search Strategies: AQuantitative Random-Walk Analysis[J]. Ecology,2005,869(11):3078-3087.
[138] Fritz H, Sa d S, Weimerskirch, H. Evidence for scale-dependent hierarchical adjustments ofmovement patterns in long range foraging animals. Proceedings of the Royal Society,London (B).2003,270:1143-1148.
[139] Nams V O. Using animal movement paths to measure response to spatial scale[J]. Oecologia,2005,143:179-188.
[140] Frair J L, Merrill E H, Visscher D R, et al. Scales of movement by elk (Cervuselaphus) inresponse to heterogeneity in forage resourcesand predation risk[J]. Landscape Ecol.2005,20:273-287.
[141] Cain M L. Random search by herbivorous insects: a simulation model[J]. Ecology,1985,66:876-888.
[142] Gross J E, Zank C, Hobbs N T, et al. Movement rules for herbivores in spatiallyheterogeneous environments: responses to small scale pattern[J]. Landscape Ecol,1995,10:209-217.
[143] Howery L D, Bailey D W, Ruyle G B, et al. Cattle use visual cues to track food locations[J].Appl Anim Behav Sci,2000,67:1-14.
[144] Bazely D R. Rules and cues used by sheep foraging in monocultures[M]. In: Hughes R N,eds. Behavioural Mechanisms of Food Selection. Berlin: Spring-Verlag,1990.344-366.
[145] Edwards G R, Newman J A, Parsons A J, et al. Use of cues by grazing animals to locatefoodpatches: an example with sheep[J]. Appl Anim Behav Sci,1997,51:59-68.
[146] Bergvall U A, Rautio P, Kesti K, et al. Associational effects of plant defences in relation towithin-and between-patch food choice by a mammalian herbivore: Neighbour contrastsusceptibility and defence[J]. Oecologia,2006,147:253-260.
[147] Oom S P, Hester A J, Elston D A, et al. Spatial interaction models: From human geographyto plant-herhivore interactions[J]. Oikos,2002,98:65-74.
[148] Palmer S C F, Hester A J, Elston D A, et al. The perils of having tasty neighbors: Grazingimpacts of large herbivores at vegetation boundaries[J]. Ecology,2003,84:2877-2890.
[149] Bee J N, Tanentzap A J, Lee W G, et al. The benefits of being in a bad neighbourhood: Plantcommunity composition influences red deer foraging decisions[J]. Oikos,2009,118:18-24.
[150] Callaway R M, Kikodze D, Chiboshvili M, et al. Unpalatable plants protect neighbors fromgrazing and increase plant community diversity[J]. Ecology,2005,86:1856-1862.
[151] Eskelinen A. Herbivore and neighbour effects on tundra plants depend on species identity,nutrient availability and local environmental conditions[J]. J Ecol,2008,96:155-165.
[152] Miller A M, McArthur C, Smethurst P J. Spatial scale and opportunities for choice influencebrowsing and associational refuges of focal plants[J]. J Anim Ecol,2009,78:1134-1142.
[153] Illius A W, Gordon I J, Elston D A, et al. Diet selection in goats: A test of intake-ratemaximization[J]. Ecology,1999,80:1008-1018.
[154] Wiggins N L, McArthur C, Davies N W. Diet switching in a generalist mammalian folivore:Fundamental to maximizing intake[J]. Oecologia,2006,147:650-657.
[155] Boone R B. Effects of fragmentation on cattle in Africansavannas under variableprecipitation[J]. Landscape Ecol,2007,22:1355-1369.
[156] Clarke J L, Welch D, Gordon I J. The influence of vegetation pattern on the grazing ofheather moorland by red deer and sheep. I. The location of animals on grass/heathermosaics[J]. J Appl Ecol,1995,32:166-176.
[157] Ward D, Saltz D. Foraging at different spatial scales: Dorcas gazelles foraging for lilies inthe NegevDesert[J]. Ecology,1994,75:48-58.
[158] Harata M, Kanemaru E, Tobisa M. Patch choice by cattle grazing tropical grass swards: apreliminary study[J]. Appl Anim Behav Sci,2006,97:134-144.
[159] Kohler F, Gillet F, Reust S, et al. Buttler A Spatial and seasonal patterns of cattle habitat usein a mountain wooded pasture[J]. Landscape Ecol,2006,21:281-295.
[160] Bergman M, Iason G R, Hester A J. Feeding patterns byroe deer and rabbits on pine, willowand birch in relation tospatial arrangement[J]. Oikos,2005,109:513-520.
[161] Newman J A. Herbivory[C]. In: Stephens D W, Brown J S, Ydenberg R C, eds. Foraging:behaviour and ecology. Chicago: University of Chicago Press,2007.175-220.
[162] Benhamou S. Spatial memory and searching efficiency[J]. Anim Behav,1994,47:1423-1433.
[163] Benhamou S. Efficiency of area-concentrated searching behaviour in a continuous patchyenvironment[J]. J Theor Biol,1992,159:67-81.
[164] Dumont B, Petit M. Spatial memory of sheep at pasture[J]. Appl Anim Behav Sci,1998,60:43-53
[165] Bergvall U A, Rautio P, Sirn H, et al. The effect of spatial scale on plant associationaldefences against mammalian herbivores[J]. Ecoscience,2008,15:343-348.
[166] Hay M E. Associational plant defenses and the maintenance of species diversity: Turningcompetitors into accomplices[J]. Am Nat,1986,128:617-641.
[167]王德利.植物与草食动物之间的协同适应及进化[J].生态学报,2004,24(11):2641-2648.
[168]王德利，高莹.竞争进化与协同进化[J].生态学杂志,2005,24(10):1182-1186.
[169] Palmer S C F, Hester A J, Elston D A, et al. The perils of having tasty neighbors: grazingimpacts of large herbivores at vegetation boundaries[J]. Ecology,2003,84:2877-2890.
[170] Bee J N, Tanentzap A J, Lee W G, et al, The benefits of being in a bad neighbourhood: Plantcommunity composition influences red deer foraging decisions[J]. Oikos,2009,118:18-24.
[171] Miller A M, McArthur C, Smethurst P J. Effects of within-patch characteristics on thevulnerability of a plant to herbivory[J]. Oikos,2007,116:41-52.
[172] Owens M K, Karen L, Launchbaugh K L, et al. Pasture characteristics affecting spatialdistribution of utilization by cattle in mixed brush communities[J]. J Range Manage,1991,44:118-123.
[173] Pinaud A, Weimerskirch H. At-sea distribution and scale-dependent foraging behaviour ofpetrels and albatrosses: a comparative study[J]. J Anim Ecol,2007,76:9-19.
[174] Giulio M D, Edwards P J. The influence of host plant diversity and food quality on larvalsurvival of plant feeding heteropteranbugs[J]. Ecol Entomol,2003,28:51-57.
[175] Specht J, Scherber C, Unsicker S B, et al. Diversity and beyond: Plant functional identitydetermines herbivore performance[J]. J Anim Ecol,2008,77:1047-1055.
[176] Milchunas D G, Noy-Meir I. Grazing refuges, external avoidance of herbivory and plantdiversity[J]. Oikos,2002,99:113-130.
[177] Agrawal A A, Lau J A, Hamb ck P A. Community heterogeneity and the evolution ofinteractions between plants and insect herbivores[J]. Q Rev Biol,2006,81:349-376.
[178] Provenza F D, Pfister J A, Cheney C D. Mechanisms of learning in diet selection withreference to phyto toxicosis in herbivores[J]. J Range Mange,1992,45:36-45.
[179] Marion G, Swain D L, Hutchings M R. Understanding foraging behavior in spatiallyheterogeneous environments[J]. J Theor Biol,2005,232:127-142.
[180] Chapman D F, Parsons A J, Cosgrove G P, et al. Impacts of spatial patterns in pasture onanimal grazing behavior, intake, and performance[J]. Crop Sci,2007,47(1):399-415.
[181] Wang D L, Han G D, Bai Y G. Interactions between foraging behavior of herbivores andgrassland resources in the eastern Eurasian steppes[C]. In: Mcgilloway D A, ed. Grassland:a Global Resource. Netherlands: Wageningen Academic Press,2005.97-110.
[182] Berteaux D, Crete M, Huot J, et al. Food choice by white-tailed deer in relation to proteinand energy content of the diet: a field experiment[J]. Oecologia,1998,115:84-92.
[183] Kyriazakis I, Oldham J D. Diet selection in sheep: the ability of growing lambs to select adiet that meets their crude protein (nitrogen×6.25) requirements[J]. Br J Nutr,1993,69:617-629.
[184] Gomez J M, Zamora R. Thorns as induced mechanical defense in a long-lived shrub(Hormathophyllaspinosa, Cruciferae)[J]. Ecology,2002,83(4):885-890..