Winter and summer weather modulate the demography of wild turkeys at the northern edge of the species distribution

Abstract

Temperate species occupying habitats at the northern limit of their geographical distribution are limited by weather and climatic conditions. Such conditions often directly affect population dynamics, and thus, influence shifts in distribution via changes in demographic parameters. We examined this question by following three distinct populations of wild turkeys inhabiting areas exposed to a gradient of meteorological conditions at the northern limit of the species distribution. Four years of radio‐telemetry on 181 birds and monitoring of 95 nests revealed that population demographics of wild turkeys were influenced by snow depth, winter temperature and summer rainfall. During winter, survival of turkeys decreased drastically when snow depth remained >30 cm for >10 days and also decreased as temperatures got colder. In the spring, snow persistence delayed nest initiation, whereas nest survival was negatively affected by rainfall. Our findings show that the effects of critical meteorological factors such as snow and temperature can be compounded when both reach the limit of a species tolerance simultaneously.

An integrated population model to project viability of a northern bobwhite population in Ohio

“…Best management practices involve targeting the vital rate with the largest influence on population growth rate (Wisdom et al 2000, Stahl andOli 2006). When a species' dominant vital rate is sensitive to severe weather, improving the species' resilience to severe weather during that critical phase of the life cycle is important to increase the overall population growth rate (Warren et al 2013, Janke et al 2015, Lavoie et al 2017). However, other vital rates may ultimately limit population growth if they are too low, even when management is effectively applied to improve the dominant vital rate (Demerdzhiev et al 2015).…”

Drivers and Consequences of Alternative Landscape Futures on Wildlife Distributions in New England, United States

“…By comparison, American black bear, gray fox, moose, and wild turkey experienced relatively large reductions in distribution and average regional occurrence (ranging between 15.7 and 51.7% decline). These species are generally more sensitive to development and climate shifts, which may explain the projected negative impacts on distribution (Renecker and Hudson, 1986;Roberts and Porter, 1998;Rustad et al, 2012;COSEWIC, 2015;Evans, 2016;Lavoie et al, 2017;Environment and Climate Change Canada, 2018;Johnson et al, 2018). High levels of decline are concerning, especially for moose and gray fox, which have been identified as Species of Greatest Conservation Need by one or more of the New England states (Maine Dept.…”

Extreme climate events limit northern range expansion of wild turkeys

“…To quantify the impact of snow, rain and temperature on wild turkey, we previously estimated the functional relationship between these climate variables and vital rates using capture-recapture data (Lavoie et al 2017). During our 3-year study (2010)(2011)(2012)(2013), we captured a total of 344 wild turkeys and classified individuals as adult (> 1 year) or yearlings (< 1 year) and determined sex based on feather coloration.…”

“…The northernmost area annually receives more than twice the snowfall from the southernmost area and has a higher proportion of forested cover (Table 1). Physical characteristics and the gradient in climate harshness are described in Lavoie et al (2017).…”

“…The widespread reintroduction programs of state game agencies have accelerated this northward expansion (Mock et al 2001) but environmental changes, especially reversion of farms to natural habitat (Hughes and Lee 2015) and reduction of snow cover caused by global warming (Ogden 2015), likely helped. Indeed, populations of wild turkeys in northern areas are limited by snow accumulation that restricts access to food (Kane et al 2007), resulting in lower survival when snow depth exceeds 30 cm for more than 10 days (Lavoie et al 2017). Furthermore, as wild turkeys need to find additional food resources when temperature decreases, the effect of temperature gets more significant above the 30 cm threshold in snow depth.…”