Harrison H. Jones

Shade coffee is among the most widespread and economically important crops in montane tropical regions and is considered more hospitable to wildlife than non‐shaded crops. Questions remain regarding the value of shade coffee as habitat for wildlife, however, given the historical research focus on small‐bodied and canopy species. Simultaneously, climate‐driven upslope migration of coffee crops represents an emerging threat to well‐conserved tropical montane forest at higher elevations. This study examined ground‐dwelling birds and medium‐large mammals in a shade coffee landscape of the Western Andes of Colombia. We asked the following questions: (1) How do bird and mammal occupancy, richness, and community composition change from continuous forest at higher elevations to middle‐elevation forest fragments and shade coffee? (2) Do birds and mammals differ in their response to shade coffee? (3) Do high‐elevation forests contribute to maintaining biodiversity in mid‐elevation shade coffee? We sampled birds and mammals with camera traps in middle‐elevation shade coffee plantations and forest fragments and in continuous forest further upslope. We then used a multi‐species occupancy model to correct for imperfect detection and to estimate occupancy, richness, and community composition. Shade coffee lacked ~50% of the bird and mammal species found in continuous forest, primarily large‐bodied and insectivorous birds and forest‐specialist and large‐bodied mammals. Forest fragment richness was closer to shade coffee than to continuous forest, but species composition significantly differed between coffee and both forest types. Birds in coffee plantations were generally a unique subset of disturbance‐adapted specialists, whereas mammals in coffee were mostly generalists. Distance from continuous forest was the most important landscape‐level predictor of occupancy for both taxa, suggesting that this forest plays a key role in maintaining biodiversity across the coffee landscape. Biodiversity conservation in shade coffee landscapes, therefore, will be ineffective unless linked to landscape‐level initiatives that conserve higher elevation tropical montane forest.

Generalist species can exhibit individual specialization (IS), where individuals adopt specialized foraging behaviors not attributable to age, sex, or social dominance. While IS increases with the diversity of available foraging resources (ecological opportunity), the potential impact of human food subsidies on ecological opportunity is unknown. We quantified the isotopic niche width of Steller's Jays ( Cyanocitta stelleri ), a synanthropic predator and dietary generalist, across a gradient of human land‐use categories ranging from subsidized (park campgrounds) to unsubsidized (forest interior) habitats in a protected area in California. We asked (1) if isotopic niche width was better predicted by individual foraging behavior than sex, social dominance, or habitat category (indicating IS) and (2) if degree of IS exhibited by jays increased with the availability of human food subsidies. We characterized the isotopic niche space occupied by individual jays relative to the population using carbon (δ 13 C) and nitrogen (δ 15 N) isotope values. Using linear models, we found that jay diet variation was best explained by individual behavior and habitat use rather than by sex or social dominance. While the degree of IS increased with the availability of human foods, individual jays exhibited a variety of foraging behaviors in all habitats that were segregated by foraging stratum and use of human foods. Individual diet also determined the degree of specialization, as jays that specialized on human foods had the narrowest niche width regardless of habitat. Management efforts targeted at generalist wildlife exhibiting large degrees of IS should therefore account for the impact of food subsidies on foraging behavior. Approaches that involve aversive conditioning may fail where highly specialized individuals are unlikely to encounter treatments; therefore, we recommend simultaneous efforts to limit human food subsidies (e.g., information campaigns and improved containment of human food and food waste), and deployment across the largest possible extent of foraging microhabitats and substrates in order to ensure exposure of whole populations to emetic eggs.