Changes in climate and land use interact to create an ecological trap in a migratory species.

Abstract

Anthropogenic landscape alteration and climate change can have multiscale and interrelated effects on ecological systems. Such changes to the environment can disrupt the connection between habitat quality and the cues that species use to identify quality habitat, which can result in an ecological trap. Ecological traps are typically difficult to identify without fine-scale information on individual survival and fitness, but this information is rarely available over large temporal and spatial scales. The Prairie Pothole Region (PPR) of the United States and Canada has undergone extensive changes in the latter half of the 20th century due to advancements in agricultural technologies, water management practices and climate change. Historically, the PPR has been a highly productive area for breeding waterfowl. While the overall trends for dabbling ducks in the PPR have exhibited increasing abundances since the late 1980s, some species, such as the northern pintail, have been declining in abundance. We used a long-term dataset of pintail counts across the PPR to separate count data into a demographic process and a habitat selection process using a hierarchical model. The hierarchical model provided an alternative way of identifying ecological traps in the absence of individual survival and fitness. Our model also allowed us to account for the indirect pathways by which climate and agriculture impact pintail through their additional contribution to wetland availability, which is a primary driver of pintail demography and habitat selection. Decoupling these processes allowed us to identify an ecological trap related to increasing cropland land cover, in which pintail selected for cropland over alternative nesting habitat, likely due to the similarities with productive native mixed-grass prairie. However, large proportions of cropland within a region resulted in fewer pintail the following year, likely due to nest failures from predation and agricultural practices. In addition, we identified several regions in Canada where this ecological trap is contributing significantly to mismatches between habitat selection and demographic processes.