Temperature can interact with landscape factors to affect songbird productivity

Abstract

Increased temperatures and more extreme weather patterns associated with global climate change can interact with other factors that regulate animal populations, but many climate change studies do not incorporate other threats to wildlife in their analyses. We used 20 years of nest-monitoring data from study sites across a gradient of habitat fragmentation in Missouri, USA, to investigate the relative influence of weather variables (temperature and precipitation) and landscape factors (forest cover and edge density) on the number of young produced per nest attempt (i.e., productivity) for three species of songbirds. We detected a strong forest cover × temperature interaction for the Acadian Flycatcher (Empidonax virescens) on productivity. Greater forest cover resulted in greater productivity because of reduced brood parasitism and increased nest survival, whereas greater temperatures reduced productivity in highly forested landscapes because of increased nest predation but had no effect in less forested landscapes. The Indigo Bunting (Passerina cyanea) exhibited a similar pattern, albeit with a marginal forest cover × temperature interaction. By contrast, productivity of the Northern Cardinal (Cardinalis cardinalis) was not influenced by landscape effects or temperature. Our results highlight a potential difficulty of managing wildlife in response to global change such as habitat fragmentation and climate warming, as the habitat associated with the greatest productivity for flycatchers was also that most negatively influenced by high temperatures. The influence of high temperatures on nest predation (and therefore, nest predators) underscores the need to acknowledge the potential complexity of species' responses to climate change by incorporating a more thorough consideration of community ecology in the development of models of climate impacts on wildlife.

Effects of temperature and precipitation on grassland bird nesting success as mediated by patch size

“…Although the mechanisms underlying this pattern are unknown, vegetation cover and fragmentation can alter microclimates (Latimer & Zuckerberg ) and mediate the effects of weather on predator activity (Cox et al. , ). During years characterized by warm May temperatures, grassland birds occupying small grasslands had lower nesting success than birds occupying larger grasslands.…”

“…References: 1, Skagen & Yackel Adams (); 2, Siikamaki (); 3, Chase et al (); 4, Rotenberry & Wiens (); 5, Stauffer et al (); 6, Cox et al (); 7, Cox et al (); 8, Dinsmore et al ().…”

“…Higher temperatures reduce productivity of Acadian Flycatchers ( Empidonax virescens ) through increased nest predation in more forested landscapes, but have little effect in less forested landscapes (Cox et al. ). At finer scales, birds can use local habitat elements and vegetative cover to adjust to extreme weather.…”

The Influence of Temperature on Black-Capped Vireo Nest-site Selection

“…Evidence suggests that birds select nest sites for thermoregulatory purposes in addition to factors involving predator avoidance and food availability (Forrester et al 1998, Nelson and Martin 1999, Tieleman et al 2008, Morgan 2012, Cox et al 2013b, Cox et al 2013a). Increases in temperatures may be influencing vireos nest site selection, as they may need more thermal refuge later in the season.…”

Synergistic effects of climate and land cover: grassland birds are more vulnerable to climate change

“…Firstly, we predict that forest birds will, on average, demonstrate weaker responses to changing temperatures and precipitation patterns than grassland birds. Secondly, we predict that an increasing amount of forest cover will ameliorate the responses of forest birds to climate change (i.e., responses of forest birds to climate change will be the weakest in regions with expansive forest cover; Cox et al 2013). Conversely, we predict that there will be little buffering capacity of grasslands, and as a result, the responses of grassland birds to climate change will remain constant across a gradient of grassland cover.…”