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

Abstract

Grassland birds are declining faster than any other bird guild across North America. Shrinking ranges and population declines are attributed to widespread habitat loss and increasingly fragmented landscapes of agriculture and other land uses that are misaligned with grassland bird conservation. Concurrent with habitat loss and degradation, temperate grasslands have been disproportionally affected by climate change relative to most other terrestrial biomes. Distributions of grassland birds often correlate with gradients in climate, but few researchers have explored the consequences of weather on the demography of grassland birds inhabiting a range of grassland fragments. To do so, we modeled the effects of temperature and precipitation on nesting success rates of 12 grassland bird species inhabiting a range of grassland patches across North America (21,000 nests from 81 individual studies). Higher amounts of precipitation in the preceding year were associated with higher nesting success, but wetter conditions during the active breeding season reduced nesting success. Extremely cold or hot conditions during the early breeding season were associated with lower rates of nesting success. The direct and indirect influence of temperature and precipitation on nesting success was moderated by grassland patch size. The positive effects of precipitation in the preceding year on nesting success were strongest in relatively small grassland patches and had little effect in large patches. Conversely, warm temperatures reduced nesting success in small grassland patches but increased nesting success in large patches. Mechanisms underlying these differences may be patch-size-induced variation in microclimates and predator activity. Although the exact cause is unclear, large grassland patches, the most common metric of grassland conservation, appears to moderate the effects of weather on grassland-bird demography and could be an effective component of climate-change adaptation.

Compensatory Breeding in Years Following Drought in a Desert-Dwelling Cooperative Breeder

“…Pied babbler groups initiated more breeding attempts and were more successful in breeding seasons following drought, indicating the presence of compensatory behavior in response to harsh conditions. Drought was the most important climaterelated predictor of reproductive effort and success in pied babblers, a finding which is consistent with other studies of birds breeding in subtropical environments (Morrison and Bolger, 2002;Skagen and Yackel Adams, 2012;Zuckerberg et al, 2018;Hidalgo Aranzamendi et al, 2019). While high temperatures during breeding attempts are commonly associated with reduced reproductive success in birds (Cunningham et al, 2013;van de Ven et al, 2020b), including in this population of pied babblers (Wiley and Ridley, 2016;Bourne et al, 2020a), we did not find strong effects of mean daily maximum temperatures calculated over the full length of the breeding season.…”

Species‐specific and temporal scale‐dependent responses of birds to drought

“…All five species that responded most strongly to annual/ near-annual temporal grains of drought are grassland birds, a guild known for its sensitivity to weather extremes (Gorzo et al, 2016;Zuckerberg, Ribic, & McCauley, 2018) and which in recent decades has experienced steep population declines (Beresford et al, 2018;Sauer & Link, 2011;Sauer, Link, Fallon, Pardieck, & Ziolkowski, 2013) and community reordering (Jones, Ripplinger, & Collins, 2017). All five species that responded most strongly to annual/ near-annual temporal grains of drought are grassland birds, a guild known for its sensitivity to weather extremes (Gorzo et al, 2016;Zuckerberg, Ribic, & McCauley, 2018) and which in recent decades has experienced steep population declines (Beresford et al, 2018;Sauer & Link, 2011;Sauer, Link, Fallon, Pardieck, & Ziolkowski, 2013) and community reordering (Jones, Ripplinger, & Collins, 2017).…”

What Have We Learned from the Land Sparing-sharing Model?

“…Land sparing, by increasing the proportion of native vegetation in the landscape, could be as or more effective than intermediate approaches in facilitating animal dispersal [148]. Evidence suggests that larger, high-quality areas of natural habitats can increase functional connectivity, promote colonisation in the face of climate change and habitat fragmentation [149], and buffer species from the effects of climate change [150,151]. Protected areas have been shown to act as 'landing pads' and then 'establishment centres' for species shifting their ranges because of climate change [152].…”