Habitat heterogeneity captured by 30‐m resolution satellite image texture predicts bird richness across the United States

Abstract

Species loss is occurring globally at unprecedented rates, and effective conservation planning requires an understanding of landscape characteristics that determine biodiversity patterns. Habitat heterogeneity is an important determinant of species diversity, but is difficult to measure across large areas using field-based methods that are costly and logistically challenging. Satellite image texture analysis offers a cost-effective alternative for quantifying habitat heterogeneity across broad spatial scales. We tested the ability of texture measures derived from 30-m resolution Enhanced Vegetation Index (EVI) data to capture habitat heterogeneity and predict bird species richness across the conterminous United States. We used Landsat 8 satellite imagery from 2013-2017 to derive a suite of texture measures characterizing vegetation heterogeneity. Individual texture measures explained up to 21% of the variance in bird richness patterns in North American Breeding Bird Survey (BBS) data during the same time period. Texture measures were positively related to total breeding bird richness, but this relationship varied among forest, grassland, and shrubland habitat specialists. Multiple texture measures combined with mean EVI explained up to 41% of the variance in total bird richness, and models including EVI-based texture measures explained up to 10% more variance than those that included only EVI. Models that also incorporated topographic and land cover metrics further improved predictive performance, explaining up to 51% of the variance in total bird richness. A texture measure contributed predictive power and characterized landscape features that EVI and forest cover alone could not, even though the latter two were overall more important variables. Our results highlight the potential of texture measures for mapping habitat heterogeneity and species richness patterns across broad spatial extents, especially when used in conjunction with vegetation indices or land cover data. By generating 30-m resolution texture maps and modeling bird richness at a near-continental scale, we expand on previous applications of image texture measures for modeling biodiversity that were either limited in spatial extent or based on coarse-resolution imagery. Incorporating texture measures into broad-scale biodiversity models may advance our understanding of mechanisms underlying species richness patterns and improve predictions of species responses to rapid global change.

A functional perspective on the analysis of land use and land cover data in ecology

“…For instance, Sentinel-2 satellites provide 10-m resolution, multispectral images every 10 days since 2015, and the Global Ecosystem Dynamics Investigation (GEDI) provides information on vegetation structure at a 25-m resolution. These remote sensing products may relate to ecological processes more strongly than traditional LULC, as demonstrated by studies relating indices of vegetation structure and species richness in birds (Farwell et al 2020) or spectral-temporal metrics and species' habitat for mammals (Oeser et al 2020). In the light of these facts, we agree with Coops and Wulder (2019) that continuous maps can be biologically more meaningful, and have significant potential in aiding studies at the interface between ecology and remote sensing.…”

Effects of local climate and habitat heterogeneity on breeding-bird assemblages of semi-natural grasslands

“…Since diverse habitats offer more available niches, habitat heterogeneity is known to be an important driver of species richness and density in breeding-bird assemblages (Benton et al 2003;Vickery and Arlettaz 2012;Farwell et al 2020). Shannon habitat diversity based on habitat types is a rather coarse proxy for habitat heterogeneity, usually not reflecting the sometimes high three-dimensional structural diversity within a certain habitat type (cf.…”

North American Breeding Bird Survey underestimates regional bird richness compared to Breeding Bird Atlases

“…The BBS has been used extensively to test patterns in the regional diversity of breeding birds in North America (Table 1). While the main goal of the BBS is to elucidate temporal trends in species abundances (Rosenberg et al, 2019; Sauer, Pardieck, et al, 2017), BBS data are also often used for large‐scale analyses of patterns in species' distributions (Rich & Currie, 2018), static species richness (Elsen et al, 2020; Farwell et al, 2020), and conservation purposes such as identifying endangered and rare species (Hudson et al, 2017; Rosenberg et al, 2017). Our results suggest that on the regional scale, BBS data miss a large number of species, both because of the survey's inability to detect rare species (Figure 7) and the similarity in habitat conditions across BBS routes (Figure 5, Appendix S2: Figure S4).…”