Sweating the small stuff: exploring the microclimate ecology of grassland birds

In this seminar, I discuss the concepts of microclimate buffering and micro-refugia as they relate to the nesting ecology of a declining grassland songbird bird community in North America's Tallgrass prairie region. Microclimates occur near the ground-surface where climate conditions vary at fine scales with heterogeneity in environmental features such as vegetation and microtopography. Microclimate conditions may impact the ecology of species in many ways, particularly if they interact with habitat at very fine resolutions. Buffering from or greater exposure to climate extremes associated with the habitat species select may inform their climate vulnerability. Grassland songbirds are the most rapidly declining avian group in North America and existing research suggests that their demographics are highly sensitive to temperature extremes and drought. Additionally, though they inhabit the same broad grassland ecosystems, grassland birds have specific microhabitat requirements that often fall along a continuum of preferences for short and sparse cover to denser and taller vegetation, sometime including shrubs. In particular, grassland obligates (e.g. specialists) are generally true-ground nesters and use relatively short grass cover. By contrast, facultative (e.g., more generalist) species often display flexibility to use denser vegetation clumps and shrubs. Here, we explored how grassland birds selected for microclimate conditions, the demographic consequences of microclimatic exposure for nesting success, and how obligate and facultative groups may differ in vulnerability to climate due to differences in their habitat associations.