Klope Maggie, Harris-Gavin Ruby, Copeland Stephanie, Orr Devyn, Young Hillary S
Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
Plants (Basel). 2025 Apr 20;14(8):1249. doi: 10.3390/plants14081249.
Large herbivore communities are changing globally, with populations of wild herbivores generally declining while domestic herbivore populations are increasing, influencing ecosystem function along with the impacts of climate change. Manipulative experiments have rarely captured the interaction between patterns of large herbivore assemblage change and climatic conditions. This interaction may affect the functional traits and functional diversity of herbaceous communities; this requires investigation, as these metrics have been useful proxies for ecosystem function. We used a large herbivore exclosure experiment replicated along a topo-climatic gradient to explore the interaction between climate and herbivore assemblage on community-level functional traits and the functional diversity of herbaceous plant understories. Our findings demonstrate interacting effects between large herbivore assemblages and climate. We found a shift from drought-tolerant traits to drought-avoidant traits with increasing aridity, specifically with regard to plant leaf area and specific leaf area. We also determined that plant community responses to grazing changed from an herbivore avoidance strategy at drier sites to a more herbivore-tolerant strategy at wetter sites. We observed that the effects of herbivores on community-level traits can sometimes counteract those of climate. Finally, we found that cattle and large wild herbivores can differ in the magnitude and direction of effects on functional traits and diversity.
大型食草动物群落正在全球范围内发生变化，野生食草动物的数量普遍减少，而家养食草动物的数量却在增加，这与气候变化的影响共同作用，影响着生态系统功能。操纵性实验很少能捕捉到大型食草动物组合变化模式与气候条件之间的相互作用。这种相互作用可能会影响草本群落的功能性状和功能多样性；这需要进行研究，因为这些指标一直是生态系统功能的有用替代指标。我们利用沿着地形气候梯度重复进行的大型食草动物围栏实验，来探究气候与食草动物组合对群落水平功能性状以及草本植物林下植被功能多样性的相互作用。我们的研究结果表明大型食草动物组合与气候之间存在相互作用。我们发现，随着干旱程度的增加，植物从耐旱性状向避旱性状转变，特别是在植物叶面积和比叶面积方面。我们还确定，植物群落对放牧的反应从较干燥地区的食草动物回避策略转变为较湿润地区的更能耐受食草动物的策略。我们观察到，食草动物对群落水平性状的影响有时会抵消气候的影响。最后，我们发现牛和大型野生食草动物在对功能性状和多样性的影响程度和方向上可能存在差异。
