距离和密度制约对吉林蛟河阔叶红松林幼苗生长的影响
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摘要
【目的】生物多样性的形成和维持机制是生态学领域的核心问题,关于距离和密度制约对温带森林幼苗生长和生物量积累影响的报道目前较为缺乏。本研究探讨温带森林是否存在距离或密度制约现象,若存在,土壤病原菌是否是距离或密度制约现象的内在驱动机制。【方法】本研究基于温室控制试验,选取吉林蛟河阔叶红松林内3个树种,对其幼苗生长进行为期4个月的动态监测,分析不同试验处理(幼苗密度、距成年母体距离和土壤杀菌)对幼苗高生长和生物量的影响。【结果】红松、水曲柳和黄檗幼苗在低密度下的高生长显著高于高密度,都表现明显的负密度制约现象。土壤杀菌处理仅能显著提高水曲柳幼苗的高生长,虽然水曲柳和黄檗幼苗高生长在距母体不同距离间存在差异,但并未表现出随离母体距离增加有助于幼苗生长的现象,研究结果不符合距离制约现象。水曲柳和黄檗幼苗根、茎、叶以及总生物量积累仅与幼苗密度显著相关,且在低密度下的根、茎、叶以及总生物量积累显著高于高密度,同样表现出负密度制约现象。而距母体距离和土壤杀菌处理对幼苗根、茎、叶以及总生物量积累均无显著影响。【结论】该温带森林中存在明显的负密度制约现象,但不存在距离制约现象。本研究认为引起幼苗密度制约性生长的因素是种内竞争,而土壤病原菌作用非常有限,且研究结果不支持距离制约性生长;其次,距离制约证据的缺乏表明,该温带森林中的病原菌并不具有强烈的宿主专一性,对幼苗密度制约性生长起作用的可能是非特异性病原菌。未来还需深入探讨种内、种间竞争和非特异性病原菌对幼苗生长的相对作用。
[Objective] Elucidating the maintenance of diversity in plant communities has long been a challenge for ecologists and a key goal of community ecology. Reports on the effects of distance and density dependence on seedling growth in temperate forests are currently lacking. We explore whether there is a distance or density dependence in temperate forests. If so, whether soil pathogens are the driving factors for distance or density dependence. [Method] Based on the greenhouse experiment, we selected three tree species in a broadleaved Korean pine forest in Jiaohe in Jilin Province of northeastern China to monitor the seedling growth for 4 months. We analyzed the effects of the seedling density, distance to adult tree(parental distances) and soil sterilization on seedling height growth and seedling biomass. [Result] The results showed that the height growth of Pinus koraiensis, Fraxinus mandschurica and Phellodendron amurense seedlings at low seedling density was significantly higher than that of high seedling density, indicating that there was significantly negative density dependence in our temperate forest. However, soil sterilization can only significantly increase the height growth of F. mandschurica seedlings. Although the height growth of F.mandschurica and P. amurense seedlings was significantly affected by the parental distances, it didn't show the trend that the seedling height grew well with increasing distance from the adult tree. Thus, our results didn't meet the phenomenon of distance dependence growth. We found that the root, stem, leaf and total biomass of F. mandschurica and P. amurense seedlings were only significantly correlated with seedling density. The root, stem, leaf and total biomass at low seedling density were significantly higher than that of high seedling density, indicating that biomass accumulation was also affected by density dependence growth.The parental distances and soil sterilization, however, had no significant effect on seedling root, stem, leaf and total biomass. [Conclusion] The results show that there is obvious negative density dependence growth in the temperate forest, but there is no distance dependence growth. This study suggests that the factor that causes the negative density dependence growth maybe the strong intraspecific competition, while the role of soil pathogens is very limited. Our results do not support the distance dependence growth. Second, the lack of evidence of distance dependence growth indicates that the soil pathogens in our temperate forest do not have intense host specificity. The generalist soil pathogens may play a role in negative density dependence growth. In the future, it is necessary to further explore the relative importance of the intra-and inter-specific competition and generalist soil pathogens in driving the seedling growth.
[Objective] Elucidating the maintenance of diversity in plant communities has long been a challenge for ecologists and a key goal of community ecology. Reports on the effects of distance and density dependence on seedling growth in temperate forests are currently lacking. We explore whether there is a distance or density dependence in temperate forests. If so, whether soil pathogens are the driving factors for distance or density dependence. [Method] Based on the greenhouse experiment, we selected three tree species in a broadleaved Korean pine forest in Jiaohe in Jilin Province of northeastern China to monitor the seedling growth for 4 months. We analyzed the effects of the seedling density, distance to adult tree(parental distances) and soil sterilization on seedling height growth and seedling biomass. [Result] The results showed that the height growth of Pinus koraiensis, Fraxinus mandschurica and Phellodendron amurense seedlings at low seedling density was significantly higher than that of high seedling density, indicating that there was significantly negative density dependence in our temperate forest. However, soil sterilization can only significantly increase the height growth of F. mandschurica seedlings. Although the height growth of F.mandschurica and P. amurense seedlings was significantly affected by the parental distances, it didn't show the trend that the seedling height grew well with increasing distance from the adult tree. Thus, our results didn't meet the phenomenon of distance dependence growth. We found that the root, stem, leaf and total biomass of F. mandschurica and P. amurense seedlings were only significantly correlated with seedling density. The root, stem, leaf and total biomass at low seedling density were significantly higher than that of high seedling density, indicating that biomass accumulation was also affected by density dependence growth.The parental distances and soil sterilization, however, had no significant effect on seedling root, stem, leaf and total biomass. [Conclusion] The results show that there is obvious negative density dependence growth in the temperate forest, but there is no distance dependence growth. This study suggests that the factor that causes the negative density dependence growth maybe the strong intraspecific competition, while the role of soil pathogens is very limited. Our results do not support the distance dependence growth. Second, the lack of evidence of distance dependence growth indicates that the soil pathogens in our temperate forest do not have intense host specificity. The generalist soil pathogens may play a role in negative density dependence growth. In the future, it is necessary to further explore the relative importance of the intra-and inter-specific competition and generalist soil pathogens in driving the seedling growth.
引文
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[13]Bagchi R,Swinfield T,Gallery R E,et al.Testing the JanzenConnell mechanism:pathogens cause overcompensating density dependence in a tropical tree[J].Ecology Letters,2010,13(10):1262-1269.
[14]Mangan S A,Schnitzer S A,Herre E A,et al.Negative plant-soil feedback predicts tree-species relative abundance in a tropical forest[J].Nature,2010,466:752-756.
[15]Konno M,Iwamoto S,Seiwa K.Specialization of a fungal pathogen on host tree species in a cross-inoculation experiment[J].Journal of Ecology,2011,99(6):1394-1401.
[16]Swamy V,Terborgh J,Dexter K G,et al.Are all seeds equal?Spatially explicit comparisons of seed fall and sapling recruitment in a tropical forest[J].Ecology Letters,2011,14(2):195-201.
[17]Liu X,Liang M,Etienne R S,et al.Experimental evidence for a phylogenetic Janzen-Connell effect in a subtropical forest[J].Ecology Letters,2012,15(2):111-118.
[18]Liu Y,Yu S,Xie Z,et al.Analysis of a negative plant-soil feedback in a subtropical monsoon forest[J].Journal of Ecology,2012,100(4):1019-1028.
[19]Liu Y,Fang S,Chesson P,et al.The effect of soil-borne pathogens depends on the abundance of host tree species[J].Nature Communications,2015,6(1):10017.
[20]Liang M,Liu X,Gilbert G S,et al.Adult trees cause densitydependent mortality in conspecific seedlings by regulating the frequency of pathogenic soil fungi[J].Ecology Letters,2016,19(12):1448-1456.
[21]Comita L S,Queenborough S A,Murphy S J,et al.Testing predictions of the Janzen-Connell hypothesis:a meta-analysis of experimental evidence for distance-and density-dependent seed and seedling survival[J].Journal of Ecology,2014,102(4):845-856.
[22]Terborgh J.Enemies maintain hyperdiverse tropical forests[J].American Naturalist,2012,179(3):303-314.
[23]Bagchi R,Gallery R E,Gripenberg S,et al.Pathogens and insect herbivores drive rainforest plant diversity and composition[J].Nature,2014,506:85-88.
[24]Hyatt L A,Rosenberg M S,Howard T G,et al.The distance dependence prediction of the Janzen-Connell hypothesis:a metaanalysis[J].Oikos,2003,103(3):590-602.
[25]Carson W P,Jill T A,Egbert G L,et al.Challenges associated with testing and falsifying the Janzen-Connell hypothesis,a review and critique[M]//Carson W P,Stefan A S.Tropical forest community ecology.Chichester:Wiley-Blackwell,2008:210-241.
[26]Yan Y,Zhang C,Wang Y,et al.Drivers of seedling survival in a temperate forest and their relative importance at three stages of succession[J].Ecology and Evolution,2015,5(19):4287-4299.
[27]Bachelot B,Uriarte M,McGuire K L,et al.Arbuscular mycorrhizal fungal diversity and natural enemies promote coexistence of tropical tree species[J].Ecology,2017,98(3):712-720.
[2]Hubbell S P,Ahumada J A,Condit R,et al.Local neighborhood effects on long-term survival of individual trees in a neotropical forest[J].Ecological Research,2001,16(5):859-875.
[3]Wright J S.Plant diversity in tropical forests:a review of mechanisms of species coexistence[J].Oecologia,2002,130(1):1-14.
[4]Bell G.The distribution of abundance in neutral communities[J].American Naturalist,2000,155(5):606-617.
[5]Janzen D H.Herbivores and the number of three species in tropical forests[J].American Naturalist,1970,104:501-528.
[6]Connell J H.On the role of natural enemies in preventing competitive exclusion in some marine animals and in rain forest trees[M]//Boer P J D,Gradwell G R.Dynamics of populations.Wageningen:Centre for Agricultural Publishing and Documentation,1971:298-313.
[7]Freckleton R P,Lewis O T.Pathogens,density dependence and the coexistence of tropical trees[J].Proceedings of the Royal Society B:Biological Sciences,2006,273:2909-2916.
[8]Harms K E,Wright S J,Calderón O,et al.Pervasive densitydependent recruitment enhances seedling diversity in a tropical forest[J].Nature,2000,404:493-495.
[9]Packer A,Clay K.Soil pathogens and spatial patterns of seedling mortality in a temperate tree[J].Nature,2000,404:278-281.
[10]Bell T,Freckleton R P,Lewis O T.Plant pathogens drive densitydependent seedling mortality in a tropical tree[J].Ecology Letters,2006,9(5):569-574.
[11]Petermann J S,Fergus A J F,Turnbull L A,et al.Janzen-Connell effects are widespread and strong enough to maintain diversity in grasslands[J].Ecology,2008,89(9):2399-2406.
[12]Li R B,Yu S X,Wan Y F,et al.Distance-dependent effects of soil-derived biota on seedling survival of the tropical tree legume Ormosia semicastrata[J].Journal of Vegetation Science,2009,20(3):527-534.
[13]Bagchi R,Swinfield T,Gallery R E,et al.Testing the JanzenConnell mechanism:pathogens cause overcompensating density dependence in a tropical tree[J].Ecology Letters,2010,13(10):1262-1269.
[14]Mangan S A,Schnitzer S A,Herre E A,et al.Negative plant-soil feedback predicts tree-species relative abundance in a tropical forest[J].Nature,2010,466:752-756.
[15]Konno M,Iwamoto S,Seiwa K.Specialization of a fungal pathogen on host tree species in a cross-inoculation experiment[J].Journal of Ecology,2011,99(6):1394-1401.
[16]Swamy V,Terborgh J,Dexter K G,et al.Are all seeds equal?Spatially explicit comparisons of seed fall and sapling recruitment in a tropical forest[J].Ecology Letters,2011,14(2):195-201.
[17]Liu X,Liang M,Etienne R S,et al.Experimental evidence for a phylogenetic Janzen-Connell effect in a subtropical forest[J].Ecology Letters,2012,15(2):111-118.
[18]Liu Y,Yu S,Xie Z,et al.Analysis of a negative plant-soil feedback in a subtropical monsoon forest[J].Journal of Ecology,2012,100(4):1019-1028.
[19]Liu Y,Fang S,Chesson P,et al.The effect of soil-borne pathogens depends on the abundance of host tree species[J].Nature Communications,2015,6(1):10017.
[20]Liang M,Liu X,Gilbert G S,et al.Adult trees cause densitydependent mortality in conspecific seedlings by regulating the frequency of pathogenic soil fungi[J].Ecology Letters,2016,19(12):1448-1456.
[21]Comita L S,Queenborough S A,Murphy S J,et al.Testing predictions of the Janzen-Connell hypothesis:a meta-analysis of experimental evidence for distance-and density-dependent seed and seedling survival[J].Journal of Ecology,2014,102(4):845-856.
[22]Terborgh J.Enemies maintain hyperdiverse tropical forests[J].American Naturalist,2012,179(3):303-314.
[23]Bagchi R,Gallery R E,Gripenberg S,et al.Pathogens and insect herbivores drive rainforest plant diversity and composition[J].Nature,2014,506:85-88.
[24]Hyatt L A,Rosenberg M S,Howard T G,et al.The distance dependence prediction of the Janzen-Connell hypothesis:a metaanalysis[J].Oikos,2003,103(3):590-602.
[25]Carson W P,Jill T A,Egbert G L,et al.Challenges associated with testing and falsifying the Janzen-Connell hypothesis,a review and critique[M]//Carson W P,Stefan A S.Tropical forest community ecology.Chichester:Wiley-Blackwell,2008:210-241.
[26]Yan Y,Zhang C,Wang Y,et al.Drivers of seedling survival in a temperate forest and their relative importance at three stages of succession[J].Ecology and Evolution,2015,5(19):4287-4299.
[27]Bachelot B,Uriarte M,McGuire K L,et al.Arbuscular mycorrhizal fungal diversity and natural enemies promote coexistence of tropical tree species[J].Ecology,2017,98(3):712-720.