LTREB: A Long-Term Study of the Role of Biotic and Abiotic Factors in a Chilean Semiarid Community

9615499 Meserve该项目现已进入第八个年头，是一项长期、大规模的实验操作，旨在研究智利半干旱社区中生物相互作用的重要性，包括捕食、种间竞争和食草动物。与此同时，正在对动植物对与气候事件有关的非生物因素的反应进行量化。到目前为止，研究结果表明，脊椎动物捕食者的数量和生存的两个核心小型哺乳动物物种的主要影响，相对较小的影响机会。一些物种的数量和生存的竞争对手的相互作用显着的时间表明干扰效应。多年生植物和短命植物的植被覆盖检测的捕食者/草食动物排除的异质性影响。几个短命物种的种子下降的小哺乳动物被排除在外的地块，建议植物物种多样性的草食动物的积极影响。这些生物反应已叠加在强大的人口反应的小型哺乳动物和植物厄尔尼诺事件。在普遍干旱期间，由于极端的资源和水的限制，生物相互作用显得不那么重要。因此，必须继续监测生物动态，以应对长期变化的周期性非生物力量。这项研究是目前最长的大规模实验研究的生物和非生物因素在温带新热带区的作用。

9615499 Meserve This project now in its eighth year is a long-term, large-scale experimental manipulation examining the importance of biotic interactions including predation, interspecific competition and herbivory in a Chilean semiarid community. At the same time, responses of plants and animals to abiotic factors related to climatic events are being quantified. Results thus far have documented that vertebrate predators had major effects on numbers and survival of two core small mammal species, and relatively minor effects on opportunistic ones. Significant time by competitor interactions on numbers and survival of some species suggests interference effects. Heterogeneous effects of predator/herbivore exclusions were detected on plant cover of perennials and ephemerals. Seeds of several ephemeral species decreased on plots where small mammals were excluded suggesting positive effects of herbivory on plant species diversity. These biotic responses have been superimposed on strong demographic responses of small mammals and plants to El Nino events. During prevailing drought periods, biotic interactions appear less important due to extreme resource and water limitation. Consequently, it is vital to continue to monitor the biotic dynamics in response to periodic abiotic forces that vary over long time scales. This study is currently the longest large-scale experimental study of the role of biotic and abiotic factors in the temperate Neotropics.