Quantifying the impacts of 166 years of land cover change on lowland bird communities

Abstract

Land cover change for agriculture is thought to be a major threat to global biodiversity. However, its ecological impact has rarely been quantified in the Northern Hemisphere, as broad-scale conversion to farmland mainly occurred until the 1400s–1700s in the region, limiting the availability of sufficient data. The Ishikari Lowland in Hokkaido, Japan, offers an excellent opportunity to address this issue, as hunter–gatherer lifestyles dominated this region until the mid-nineteenth century and land cover maps are available for the period of land cover changes (i.e. 1850–2016). Using these maps and a hierarchical community model of relationships between breeding bird abundance and land cover types, we estimated that broad-scale land cover change over a 166-year period was associated with more than 70% decline in both potential species richness and abundance of avian communities. We estimated that the abundance of wetland and forest species declined by greater than 88%, whereas that of bare-ground/farmland species increased by more than 50%. Our results suggest that broad-scale land cover change for agriculture has led to drastic reductions in wetland and forest species and promoted changes in community composition in large parts of the Northern Hemisphere. This study provides potential baseline information that could inform future conservation policies.

Where wolves were: setting historical baselines for wolf recovery in Spain

“…Similar approaches could be developed for different areas and/or different species, taking advantage of the rich documentary heritage existing in several areas of the world (Turvey, Crees, & Di Fonzo, 2015; Viana et al ., 2022). In regions and/or time frames for which written sources are not available, informative baselines for species or natural systems can also be generated from other sources, such as archaeological data (McKechnie et al ., 2014; Reeder‐Myers et al ., 2022), historical maps (Kitazawa et al ., 2022), pictorial sources (from rock art to photographs; Drake et al ., 2011; Depauw et al ., 2022) or from natural archives (e.g. palynological series; Szabó et al ., 2017).…”

Phylogenomics reveals an island as a genetic reservoir of a continental population

“…We compared the effective population size ( N e ) estimates with the contemporary population size to understand the spatial extent of the populations by converting census population size ( N c ) in Kitazawa et al (2022) to effective population size of a Hokkaido region including Tomakomai by using a mean ratio of N c : N e = 1:0.44 for birds (Frankham, 1995).…”

“…These methods are complementary to each other because SWP2 is a nonparametric model that can flexibly infer complex effective population size ( N e ) changes over time yet without modeling gene flow, while FSC2 has an advantage of jointly modeling gene flow and N e changes but in a simplified user-defined model (Nadachowska-Brzyska et al 2022). Because the contemporary N e may differ from the model estimates due to recent demographic changes that may not be detected by some of the models (Nadachowska-Brzyska et al 2022), we estimated the contemporary N e of the island population by converting estimated census population size ( N c ) in a plain of Hokkaido in early nineteenth century (Kitazawa et al 2022), using a mean ratio of N c : N e = 1:0.44 for birds (Frankham 1995).…”

“…In the SWP2 analysis, the timing that a population started to show different demography could be interpreted as the timing of divergence, which can further support population history. We compared the effective population size (N e ) estimates with the contemporary population size to understand the spatial extent of the populations by converting census population size (N c ) in Kitazawa et al (2022) to effective population size of a Hokkaido region including Tomakomai by using a mean ratio of N c :N e = 1:0.44 for birds (Frankham, 1995).…”