Herbivore-plant interactions have been shown to play central roles in determining the structure of salt marsh communities. However, relatively little is known about how marsh herbivory varies over small spatial scales (e.g., < 2 km) within a single geographic region as well as the potential driving forces for such variability. Here we quantify the small-scale spatial variablity in insect grazing on three Juncus roemerianus marshes in Grand Bay National Estuarine Research Reserve, MS, USA. Sampling covered both monthly and seasonal temporal scales (February to November) to capture the well described seasonality in insect grazing in these marshes Our results show large differences in abundance of insect herbivores and intensity of herbivory across, but not within, the three marshes. In addition, the observed spatial differences in herbivory do not appear to be related to herbivore abundance or insect species, but potentially to differences in landscape context, such as proximity to upland habitats (i.e., forestland) or habitat fragmentation. These results demonstrate that insect herbivory in marshes can also vary substantially at small spatial scales and we suggest some mechanisms responsible for such differences.

草食动物与植物的相互作用已被证明在决定盐沼群落结构中起着核心作用。然而，关于沼泽草食动物如何在单个地理区域内的较小空间尺度（例如，<2 km）上变化以及这种变化的潜在驱动力知之甚少。在这里，我们量化了三只杜鹃（Juncus roemerianus）上放牧昆虫的小范围空间变异性沼泽在美国MS大湾国家河口研究保护区。采样涵盖了月度和季节时标（2月至11月），以捕获这些沼泽地中放牧的昆虫的描述性良好的季节性。我们的结果表明，三个沼泽地中（而非内部）的昆虫食草动物的数量和食草性的强度差异很大。此外，所观察到的草食动物的空间差异似乎与草食动物的丰度或昆虫种类无关，但可能与景观环境的差异有关，例如与高地栖息地（即林地）的接近程度或栖息地破碎化。这些结果表明，沼泽中的昆虫食草也可以在较小的空间尺度上发生很大变化，并且我们提出了造成这种差异的一些机制。