Effects of flyway‐wide weather conditions and breeding habitat on the breeding abundance of migratory boreal waterbirds

Abstract

Anthropogenic habitat loss and climate change are among the major threats to biodiversity. Bioclimatic zones such as the boreal and arctic regions are undergoing rapid environmental change, which will likely trigger changes in wildlife communities. Disentangling the effects of different drivers of environmental change on species is fundamental to better understand population dynamics under changing conditions. Therefore, in this study we investigate the synergistic effect of winter and summer weather conditions and habitat type on the abundance of 17 migratory boreal waterbird species breeding in Finland using three decades of count data. We found that above-average temperatures and precipitations across the western and northern range of the wintering grounds have a positive impact on breeding numbers in the following season, particularly for waterbirds breeding in eutrophic wetlands. Conversely, summer temperatures did not seem to affect waterbird abundance. Moreover, waterbird abundance was higher in eutrophic than in oligotrophic wetlands, but long term trends indicated that populations are decreasing faster in eutrophic than in oligotrophic wetlands. Our results suggest that global warming may apparently benefit waterbirds, e.g. by increased winter survival due to more favourable winter weather conditions. However, the observed population declines, particularly in eutrophic wetlands, may also indicate that the quality of breeding habitat is rapidly deteriorating through increased eutrophication in Finland which override the climatic effects. The findings of this study highlight the importance of embracing a holistic approach, from the level of a single catchment up to the whole flyway, in order to effectively address the threats that waterbirds face on their breeding as well as wintering grounds.

Potential of restoration of gravel-sand pits for Bats

“…Using similar modelling approaches (GLMMs with negative binomial error distribution), as previously, we focused our analysis on variation of the global effect, independently of the considered species, between the five gravel-sand pit states (before operating, during quarrying and three rehabilitation categories depending on the elapsed time after the quarry stopped operating). Thus, we added species identity as a random effect to account for differences in abundance between species (Jiguet et al 2010, Pavón-Jordán et al 2017, Pellissier et al 2013). Our statistical models were structured in the following way:…”

Temperature and precipitation at migratory grounds influence demographic trends of an Arctic‐breeding bird

“…Among terrestrial mammals, Vetter, Ruf, Bieber, and Arnold (2015) and Weiskopf, Ledee, and Thompson (2019) link increased abundance of wild boar ( Sus scrofa ) in Europe and white‐tailed deer ( Odocoileus virginianus ) in North America to improved survival during ambient, warmer winters and to bottom‐up effects of warmer temperatures on forage plant availability. Similarly, warmer, wetter weather improves winter survival of waterbirds in northern Europe, likely due to reduced energetic and thermoregulatory costs (Pavón‐Jordán, Santangeli, & Lehikoinen, 2017). Warmer early breeding season temperatures are found to improve productivity in pink‐footed geese ( Anser brachyrhynchus ) and snow geese ( Anser caerulescens ), likely driven by earlier access to forage and nesting sites because of early snow melt (Jensen, Madsen, Johnson, & Tamstorf, 2014; Morrissette, Bêty, Gauthier, Reed, & Lefebvre, 2010).…”

Shifts in fine‐scale distribution and breeding success of boreal waterbirds along gradients in ice‐out timing and habitat structure

“…This suggests that the ecological status of eutrophic lakes in Finland has not improved despite considerable water protection measures (Räike et al, 2020). The finding that waterbird species and populations associated with eutrophic lakes have decreased more than those breeding on oligotrophic lakes points in the same direction, suggesting that the quality of eutrophic lakes as a breeding habitat has decreased (Lehikoinen et al, 2016;Pavón-Jordán et al, 2017;Pöysä et al, 2013; see also Elmberg et al, 2020;Pöysä et al, 2019).…”