Combining environmental niche models, multi‐grain analyses, and species traits identifies pervasive effects of land use on butterfly biodiversity across Italy

Abstract

Understanding how species respond to human activities is paramount to ecology and conservation science, one outstanding question being how large‐scale patterns in land use affect biodiversity. To facilitate answering this question, we propose a novel analytical framework that combines environmental niche models, multi‐grain analyses, and species traits. We illustrate the framework capitalizing on the most extensive dataset compiled to date for the butterflies of Italy (106,514 observations for 288 species), assessing how agriculture and urbanization have affected biodiversity of these taxa from landscape to regional scales (3–48 km grains) across the country while accounting for its steep climatic gradients. Multiple lines of evidence suggest pervasive and scale‐dependent effects of land use on butterflies in Italy. While land use explained patterns in species richness primarily at grains ≤12 km, idiosyncratic responses in species highlighted “winners” and “losers” across human‐dominated regions. Detrimental effects of agriculture and urbanization emerged from landscape (3‐km grain) to regional (48‐km grain) scales, disproportionally affecting small butterflies and butterflies with a short flight curve. Human activities have therefore reorganized the biogeography of Italian butterflies, filtering out species with poor dispersal capacity and narrow niche breadth not only from local assemblages, but also from regional species pools. These results suggest that global conservation efforts neglecting large‐scale patterns in land use risk falling short of their goals, even for taxa typically assumed to persist in small natural areas (e.g., invertebrates). Our study also confirms that consideration of spatial scales will be crucial to implementing effective conservation actions in the Post‐2020 Global Biodiversity Framework. In this context, applications of the proposed analytical framework have broad potential to identify which mechanisms underlie biodiversity change at different spatial scales.

Integrating presence‐only and presence–absence data to model changes in species geographic ranges: An example in the Neotropics

“…A challenge when testing species interactions will be the dependency of these on the scale of analysis. At smaller spatial scales, species' reactions to environmental factors may reflect their preferences for particular habitats or how they use space, while at larger scales, their responses may indicate broader ecological patterns such as metacommunity dynamics, biogeographical limitations, and energy constraints (Connor et al, 2019; Riva et al, 2023).…”

Patch‐scale edge effects do not indicate landscape‐scale fragmentation effects

“…In some cases, large‐scale coordinated data‐collection efforts are needed (e.g., Sirami et al., 2019). Recent increases in citizen science databases (e.g., eBird, NatureServe) may alleviate this, but these have sampling biases that must be accounted for (Dickinson et al., 2010; e.g., Riva et al., 2023).…”

Obstruction of biodiversity conservation by minimum patch size criteria

“…Although some species requiring large amounts of habitat likely have already disappeared from human‐dominated regions (Chetcuti et al., 2020; Riva et al., 2023; Vellend et al., 2017), there is little evidence that these species are generally negatively affected by fragmentation if sufficient habitat is available, such that remnant patches are within reach for dispersal. On the contrary, empirical and theoretical work demonstrates that biodiversity in some metacommunities persists more readily in large numbers of small patches, even if populations inhabiting such small patches are isolated and exposed to higher extinction risks (Hammill & Clements 2020; Luo et al., 2022; Wang & Altermatt 2019).…”