Coherence of terrestrial vertebrate species richness with external drivers across scales and taxonomic groups

Abstract

Aim: Understanding connections between environment and biodiversity is crucial for conservation, identifying causes of ecosystem stress, and predicting population responses to changing environments. Explaining biodiversity requires an understanding of how species richness and environment covary across scales. Here, we identify scales and locations at which biodiversity is generated and correlates with environment.Location: Full latitudinal range per continent. Time Period: Present day.Major Taxa Studied: Terrestrial vertebrates: all mammals, carnivorans, bats, songbirds, hummingbirds, amphibians. Methods:We describe the use of wavelet power spectra, cross-power and coherence for identifying scale-dependent trends across Earth's surface. Spectra reveal scaleand location-dependent coherence between species richness and topography (E), mean annual precipitation (Pn), temperature (Tm) and annual temperature range (ΔT).Results: >97% of species richness of taxa studied is generated at large scales, that is, wavelengths ≳ 10 3 km, with 30%-69% generated at scales ≳ 10 4 km. At these scales, richness tends to be highly coherent and anti-correlated with E and ΔT, and positively correlated with Pn and Tm. Coherence between carnivoran richness and ΔT is low across scales, implying insensitivity to seasonal temperature variations. Conversely, amphibian richness is strongly anti-correlated with ΔT at large scales. At scales ≲ 10 3 km, examined taxa, except carnivorans, show highest richness within the tropics. Terrestrial plateaux exhibit high coherence between carnivorans and E at scales ∼ 10 3 km, consistent with contribution of large-scale tectonic processes to biodiversity. Results are similar across different continents and for global latitudinal averages.Spectral admittance permits derivation of rules-of-thumb relating long-wavelength environmental and species richness trends.Main Conclusions: Sensitivities of mammal, bird and amphibian populations to environment are highly scale dependent. At large scales, carnivoran richness is largely independent of temperature and precipitation, whereas amphibian richness correlates

Diversity gradients of terrestrial vertebrates – substantial variations about a common theme

“…Most studies that examined richness-environment relationship of terrestrial vertebrates were confined to one or two tetrapod classes (Allen et al, 2002;Araújo et al, 2008;Barreto et al, 2019;Costa et al, 2007;Evans et al, 2005;Foody, 2004;Fritz et al, 2016;Kerr & Packer, 1997;Qian et al, 2007;Rahbek & Graves, 2001;Rodríguez et al, 2005), or involve birds, mammals, and amphibians (Belmaker & Jetz, 2011;Bohdalková et al, 2021;Buckley & Jetz, 2007;Davies et al, 2007;Gouveia et al, 2013;Grenyer et al, 2006;Gudex-Cross et al, 2022;Hawkins et al, 2007Hawkins et al, , 2012Hortal et al, 2008;O'Malley et al, 2023;Wu & Liang, 2018). Studies that incorporate all tetrapods (including reptiles) have usually been confined to one region (Currie, 1991;Lewin et al, 2016;Powney et al, 2010;Tallowin et al, 2017;.…”