Livestock reduces juvenile tree growth of alien invasive species with a minimal effect on natives: a field experiment using exclosures

详细信息    查看全文

• 作者：Emanuel Andrés Capó ; Ramiro Aguilar ; Daniel Renison
• 关键词：Browsing ; Herbivory ; Cattle ; Non ; native ; Exotic
• 刊名：Biological Invasions
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：18
• 期：10
• 页码：2943-2950
• 全文大小：501 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Sciences
  Ecology
  Hydrobiology
  Zoology
  Forestry
  
• 出版者：Springer Netherlands
• ISSN：1573-1464
• 卷排序：18

文摘

Many alien invasive tree species were originally introduced to their non-native ranges for use in forestry and as urban trees. These alien species were selected for their fast growth and not necessarily for possessing mechanisms which deter browsing. Instead, many tree species native to semiarid areas of the world evolved mechanisms which deter browsing, presumably at the cost of slower growth. In a semiarid rangeland we observed that livestock exclusion greatly promoted the growth of juveniles of several alien species but not of native species, and we hypothesized that this increase in growth of aliens was due to livestock preference for alien and not native trees. With the objective of quantifying our observations and understanding the mechanism underlying the increased growth rates of alien juvenile trees under livestock exclusion, we assessed growth and browsing levels in juveniles of two alien invasive and four abundant native tree species within three parcels where livestock was excluded and three parcels with livestock at 0.20 cattle equivalents.ha−1. Alien species grew around four-fold faster under livestock exclusion than with livestock and, as predicted, received five times more browsing than natives. Instead, native species did not significantly increase their growth rate with livestock exclusion. The results support our hypothesis and the implications for management would be that stocking paddocks with livestock to browse existing alien juveniles and re-growth of felled adults should be effective in delaying invasions of trees used for forestry without significantly affecting the growth of the most abundant native trees.