1. Since 1993, have there been changes in Great Lakes Piping Plover reproductive phenology? Since 1993, have there been climate-induced changes in Great Lakes Piping Plover reproductive success? Is Climate Change Altering the Breeding Biology of the Endangered Great Lakes Piping Plover? ABSTRACT As average global temperature rises, heterogeneous changes from region to region are expected. Regional changes will most directly impact ecology and conservation efforts. These impacts on ecosystems which must be taken into account when designing conservation programs. In the Great Lakes region, among the ways climate change will manifest itself are changes in temperature trends, seasonality and water levels. The Great Lakes Piping Plover nests in shoreline habitat which is sensitive to climate-induced events. By predicting scenarios of the effects of global climate change on the Piping Plover and its habitat we can make informed management decisions. I have completed analyses on available Piping Plover reproductive data. The Piping Plover is nesting earlier. Earlier mean nest initiation correlates with fewer days in May with low temperature below 40°F. Also examined were correlations between precipitation and reproductive success and correlations between lake levels and reproductive success. These correlations are less clear, but may become more important with future changes in amount of lake level fluctuation, overall water level changes and changes in weather patterns. HOW MIGHT CLIMATE CHANGE AFFECT THE GREAT LAKES PIPING PLOVER? REPRODUCTIVE PHENOLOGY I examined whether or not Great Lakes Piping Plovers have exhibited a trend towards earlier nesting by running a linear regression using R software on average nest initiation date versus year (Figure 4). This data was obtained from the University of Minnesota Piping Plover database and Piping Plover recovery reports as submitted to the Michigan Department of Natural Resources. I then looked at whether there was a correlation between May temperature and nest initiation data (Figure 5). Finally, I examined nest initiation date as a function of population size. In light of piping plover recovery, this could be a factor in earlier nest initiation that would be separate from any climatological factor (Figure 6). REPRODUCTIVE SUCCESS AND CLIMATOLOGICAL CHANGES I completed regression on reproductive success versus Lake Michigan/Huron lake level to determine whether Great Lakes Piping Plover reproductive success changed since 1993 as a function of lake level. I also did regression on reproductive success versus overall June precipitation and number of days in June with significant rainfall (mean precipitation of two weather stations is more than 0.10 inches during a 24-hour period), to determine whether Great Lakes Piping Plover reproductive success has changed since 1993 as a function of precipitation in the region. RESULTS Since 1993, Great Lakes Piping Plovers have initiated nesting 1 to 2 days earlier every 2 years. This is statistically significant (P-value = 0.03). The rate of change is such that per one fewer day in May with a low temperature of 40  F, the mean nest initiation date is approximately 1 day earlier. 44% of the variation in nest initiation date can be explained by cold days. This is statistically significant (P-value = 0.01). If I remove the point for the year 2004 (the most deviant point), the rate of change remains similar, but 66% of the variation in nest initiation date can be explained by cold days. RESULTS At this time, there is no statistically significant correlation between lake levels and reproductive success from 1993 to 2006 (Figure 6). However, there seems to be some relationship. Lower lake levels tend towards higher reproductive success. This may become significant in the future as lake level fluctuations change or lake levels change overall. Also, there is no statistically significant correlation between overall June precipitation and reproductive success from 1993 to 2006 (Figure 7). Again, in this case, there seems to be some relationship. Lower precipitation in June seems to tend towards higher reproductive success. There is a statistically significant correlation between reproductive success and number of days in June with precipitation totaling more than 0.1 inches (Figure 8). More days with precipitation events correlate with lower reproductive success. THE PIPING PLOVER The Piping Plover (Charadrius melodus) is a small shorebird. Its cryptic coloring blends into the open, sandy habitat on the beaches where it feeds and nests. Piping Plovers have historically been common in the Great Lakes region (Figure 1). The estimated historic Great Lakes population of Piping Plovers is 500-800 pairs. Today there are significantly fewer breeding pairs in the Great Lakes region compared to early 1900s. The Great Lakes Piping Plover is biologically significant as an umbrella species as it co-occurs with other rare coastal species. Thus, the endangered status of the Piping Plover helps to protect the entire Great Lakes coastal dune habitat. PIPING PLOVER RECOVERY EFFORTS The Great Lakes Piping Plover was listed as federally endangered in 1986. Recovery efforts have resulted in 53 breeding pairs in 2006 (Figure 3). Despite this recovery, the Piping Plover population is still vulnerable to extinction. The plovers are vulnerable to predation, continued beach development means further habitat loss, and greater human presence means more wild and domestic predators as well as human disturbance. The small population is vulnerable to demographic and environmental stochasticity. 13 19 16 14 18 12 17 16 18 19 21 23 24 32 30 32 51 50 58 53 54 0 10 20 30 40 50 60 198519891993199720012005 Year Breeding Pairs 1984: 13 recorded pairs 1986 : Listed endangered 2006: 53 pairs Nebraska Game and Parks Commission CONCLUDING REMARKS It is imperative to take climate change scenarios into account when designing conservation programs for the species, communities and ecosystems that are most vulnerable to the impacts of climate change. Easterling et al. (2000) suggest that we can ameliorate large uncertainties in regional climate change scenarios by creating more connections between ecology and climatology. Given climate change predictions and current Piping Plover behavior, early nesting will likely continue. Management and conservation efforts will need adjustment (e.g. field season will start earlier). We should continue to monitor Piping Plover phenology trends and incorporate phenology information into conservation plans. Climate change that affects quantity and quality of shoreline habitat will also affect Piping Plovers. Lake levels and precipitation will become more important to Piping Plover fledging success via changes in amount of lake level fluctuation, predicted overall water level decreases (Kling et al. 2003) and changes in weather patterns. Other behavior (e.g. migration) may ultimately be affected. Figure 4Figure 5Figure 6 FUTURE WORK To further investigate the impact of climate change on the Great Lakes Piping Plover, we could examine relationships between fledging success and specific weather events: flooding, storms, cold events and examine relationships between population success and weather in the wintering grounds. We should continue to analyze habitat: are nest sites changing in response to climate conditions? Are there measurable trends in distribution of nests? Are there significant changes in vegetation? It also might be telling to analyze phenology of emergence of Piping Plover food sources (e.g. midge and mayfly hatch dates). RESEARCH QUESTIONS Global warming has altered the distributions of organisms and changed the phenology of flowering in plants and reproduction and migration in animals (Cotton 2003, Both and Visser 2001). Heterogeneous regional changes will most directly impact ecology and conservation (Walther and Post et al. 2002). Ultimately, changes in climate will alter species distributions, abundance and behavior. The Piping Plover nests on shoreline sensitive to climate-induced events. Climate change may affect a number of habitat traits: temperature trends; seasonality; lake water levels; winter lake ice coverage; and synoptic weather patterns (Kling et al. 2003). Reduction in winter ice coverage may result in greater winter evaporation resulting in lower water levels. Less ice would mean less shore scouring and possibly more vegetation, including invasive species. Also, there could be differences between climate-induced changes in plovers’ wintering grounds versus breeding grounds. Figure 3 Figure 7 Figure 6 Figure 8 ACKNOWLEDGEMENTS Cathy Haffner, Jesse Kroese, Olivia LeDee, Vanessa Pompei, Erin Roche, Jennifer Stucker, Lauren Wemmer Biosphere/Atmosphere Research and Training, NSF/IGERT University of Michigan Biological Station University of MN Conservation Biology Program DATA SOURCES AND CONTACT INFORMATION Plover data Great Lakes Piping Plover Population Database, maintained by F. Cuthbert and graduate students, University of Minnesota Lake level data United States Army Corps of Engineers Weather data Regional weather station data (National Center Atmospheric Research) For extended citation list contact Amy Canavan at cana0022@umn.edu C. Perez (USWFS) Lauren Wemmer Amy Canavan Conservation Biology University of MN Biosphere/Atmosphere Research & Training (NSF/IGERT) Francesca J. Cuthbert Professor and Interim Head Fisheries, Wildlife, and Conservation Biology, University of MN