COS 50-1 - Increased climatic vulnerability of migratory birds under intensified land use

Wednesday, August 14, 2019: 8:00 AM
L013, Kentucky International Convention Center
Qing Zhao1, Todd Arnold2, Jim H. Devries3, David W. Howerter3, Robert Clark4 and Mitch Weegman1, (1)School of Natural Resources, University of Missouri, Columbia, MO, (2)University of Minnesota, (3)Institute for Wetland and Waterfowl Research, Ducks Unlimited Canada, Stonewall, MB, Canada, (4)Environment and Climate Change Canada, Saskatoon, SK, Canada
Background/Question/Methods

It is essential to understand the effects of land use patterns in altering climatic resiliency/vulnerability of natural populations. However, it is particularly difficult to study the interactive effects of land use and climate on the demography of migratory species, which rely on different landscapes throughout the year. Among migratory birds, the population trajectory of North American northern pintails (Anas acuta; hereafter pintails) during the last decades is particularly puzzling because they did not respond to favourable environmental conditions as most other North American waterfowls did. The mechanisms and drivers involved in this divergence remain poorly understood. While pintails are similar to other ducks in their dependence on wetlands throughout their annual cycle, their extensive use of croplands for nesting differentiates them and makes them particularly vulnerable to changes in agricultural land use on prairie breeding grounds. Our goal was to quantify how changes in land use and wetland habitats (measured as pond counts) on breeding grounds have influenced pintail demography and population dynamics. We developed an integrated population model to analyse long-term (1961–2014) of band-recovery, breeding population survey, land use and pond count data that cover a large spatial extent including Prairie Potholes and parkland habitats.

Results/Conclusions

We found that pintail productivity contributed more than female and male survival in population growth rate. Productivity was positively affected by pond count and negatively affected by agricultural intensification. Further, we found a positive interactive effect of pond count and agricultural intensification on pintail productivity. While this positive interaction was insufficient to overcome the strong negative effect of agricultural intensification on pintail productivity across nearly all pond counts, it indicated that that pintail productivity, and thus populations were more negatively impacted by drought conditions associated with climate change under higher agricultural intensification. We also found that female and male survival was subjected to negative density dependent processes and positive effects of pond. Our results indicate that pintail populations have become more vulnerable to climate change under intensified land use, which suggests that future conservation strategies must adapt to these altered relationships. The interacting effects of land use and climate on demography should be considered more frequently in population ecology, and integrated population models provide an adaptable framework to understand vital rates and their drivers simultaneously.