PDF(Pubmed)
Abstract：
Food availability varies considerably over space and time in wetland systems, and consumers must be able to track those changes during energetically-demanding points in the life cycle like breeding. Resource tracking has been studied frequently among herbivores, but receives less attention among consumers of macroinvertebrates. We evaluated the change in resource availability across habitat types and time and the simultaneous density of waterfowl consumers throughout their breeding season in a high-elevation, flood-irrigated system. We also assessed whether the macroinvertebrate resource density better predicted waterfowl density across habitats, compared to consistency (i.e., temporal evenness) of the invertebrate resource or taxonomic richness. Resource density varied marginally across wetland types but was highest in basin wetlands (i.e., ponds) and peaked early in the breeding season, whereas it remained relatively low and stable in other wetland habitats. Breeding duck density was positively related to resource density, more so than temporal resource stability, for all species. Resource density was negatively related to duckling density, however. These results have the potential to not only elucidate mechanisms of habitat selection among breeding ducks in flood-irrigated landscapes but also suggest there is not a consequential trade-off to selecting wetland sites based on energy density versus temporal resource stability and that good-quality wetland sites provide both.
摘要：
湿地系统的食物供应在空间和时间上差异很大，消费者必须能够在生命周期中的能量需求点跟踪这些变化，如育种。在食草动物中经常研究资源跟踪，但在大型无脊椎动物消费者中受到的关注较少。我们评估了栖息地类型和时间之间的资源可用性变化，以及整个高海拔繁殖季节水禽消费者的同时密度，洪水灌溉系统。我们还评估了大型无脊椎动物资源密度是否更好地预测了整个栖息地的水禽密度，与一致性相比(即，无脊椎动物资源或分类学丰富度的时间均匀度）。不同湿地类型的资源密度略有差异，但在流域湿地中最高(即，池塘)并在繁殖季节早期达到顶峰，而在其他湿地栖息地中，它仍然相对较低且稳定。养殖鸭密度与资源密度呈正相关,不仅仅是时间资源稳定性，对于所有物种。资源密度与小鸭密度呈负相关,however.这些结果不仅有可能阐明洪水灌溉景观中种鸭的栖息地选择机制，而且还表明，根据能量密度与时间资源稳定性以及优质湿地选择湿地地点并没有相应的权衡。
