Individual-level patterns of resource selection do not predict hotspots of contact

Abstract

Contact among animals is crucial for various ecological processes, including social behaviors, disease transmission, and predator–prey interactions. However, the distribution of contact events across time and space is heterogeneous, influenced by environmental factors and biological purposes. Previous studies have assumed that areas with abundant resources and preferred habitats attract more individuals and, therefore, lead to more contact. To examine the accuracy of this assumption, we used a use-available framework to compare landscape factors influencing the location of contacts between wild pigs (Sus scrofa) in two study areas in Florida and Texas (USA) from those influencing non-contact space use. We employed a contact-resource selection function (RSF) model, where contact locations were defined as used points and locations without contact as available points. By comparing outputs from this contact RSF with a general, population-level RSF, we assessed the factors driving both habitat selection and contact. We found that the landscape predictors (e.g., wetland, linear features, and food resources) played different roles in habitat selection from contact processes for wild pigs in both study areas. This indicated that pigs interacted with their landscapes differently when choosing habitats compared to when they encountered other individuals. Consequently, relying solely on the spatial overlap of individual or population-level RSF models may lead to a misleading understanding of contact-related ecology. Our findings challenge prevailing assumptions about contact and introduce innovative approaches to better understand the ecological drivers of spatially explicit contact. By accurately predicting the spatial distribution of contact events, we can enhance our understanding of contact based ecological processes and their spatial dynamics.

Correlated host movements can reshape spatio-temporal disease dynamics: modeling the contributions of space use to transmission risk using movement data

“…Our analyses emphasize the importance of this next step by showing that correlations at a local (cell) scale can create a vastly more heterogeneous transmission landscape. Moreover, correlations can lead to localized transmission hotspots that are not necessarily predictable from joint space use (Yang et al, 2023a), and may contribute to the growing empirical recognition that fine-scale, localized transmission hotspots are present in many empirical host-pathogen systems (Albery et al, 2021). Whether these localized transmission hotspots are predictable a priori remains to be seen, but ignoring correlated movements can make the task orders of magnitude more difficult for some pathogens.…”

“…This limits our ability to ask questions like: how do non-independent movements affect spatio-temporal infection risk, compared to spatial overlap? Moreover, recent studies have shown that spatial transmission risk can be highly localized (Albery et al, 2021) and is not necessarily predicted by animal space use (Yang et al, 2023a). We hypothesize that non-independent animal movements can (at least partially) account for these observations and develop a modeling approach to rigorously test this hypothesis and systematically quantify the contribution of space use and correlated movements to spatio-temporal transmission risk.…”