Anthropogenic disturbance and climate change are the main drivers of biodiversity loss and ecological services around the globe. There is concern that climate change will exacerbate the impacts of disturbance and thereby promote biotic homogenization, but its consequences for ecological services are unknown. We investigated the individual and interactive effects of increasing chronic anthropogenic disturbance (CAD) and aridity on seed dispersal services provided by ants in Caatinga vegetation of north‐eastern Brazil. The study was conducted in Catimbau National Park, Pernambuco, Brazil. Within an area of 214 km2, we established nineteen 50 × 20 m plots that encompassed gradients of both CAD and aridity. We offered diaspores of six plant species, three myrmecochorous diaspores and three fleshy fruits that are secondarily dispersed by ants. We then quantified the number of interactions, seed removal rate and dispersal distances, and noted the identities of interacting ant species. Finally, we used pitfall trap data to quantify the abundances of ant disperser species in each plot. Our results show that overall composition of ant disperser species varied along the gradients of CAD and aridity, but the composition of high‐quality dispersers varied only with aridity. The total number of interactions, rates of removal and mean distance of removal all declined with increasing aridity, but they were not related to CAD. These same patterns were found when considering only high‐quality disperser species, driven by the responses of the dominant disperser Dinoponera quadriceps. We found little evidence of interactive effects of CAD and aridity on seed dispersal services by ants. Our study indicates that CAD and aridity act independently on ant‐mediated seed dispersal services in Caatinga, such that the impacts of anthropogenic disturbance are unlikely to change under the forecast climate of increased aridity. However, our findings highlight the vulnerability of seed dispersal services provided by ants in Caatinga under an increasingly arid climate due to low functional redundancy in high‐quality disperser species. Given the large number of plant species dependent on ants for seed dispersal, this has important implications for future plant recruitment and, consequently, for the composition of Caatinga plant communities.

1 The release from bottom-up control is a key process promoting the proliferation of leaf-cutting ants (LCA) along neotropical rainforest edges. Considering the preference of LCA for drought-stressed plants, edge-induced drought-stress in plants could be one of the mechanisms behind this bottom-up response. We hypothesized that plants growing along the forest edge suffer higher levels of drought stress, which makes them a more suitable food resource for LCA and affects LCA colony density in a Brazilian Atlantic rainforest remnant. Additionally, we investigated whether this effect is stronger in north-facing edges because the radiation load is higher in this edge aspect in the southern hemisphere. 2 We examined LCA colony density and plant relative water content (RWC) by relating them to edge distance and edge orientation. 3 We recorded 57 LCA colonies in which the density showed an approximately six-fold increase within the first 50 m of the forest compared with distances > 150 m. North-facing edges presented an approximately four-fold higher colony density compared with other edge aspects. Among the 296 plant individuals sampled, the average RWC was unrelated to edge distance, although plants growing near north-facing edges had approximately 10% lower RWC values compared with in south-facing edges. We also found that, considering edge orientation, the lower the average RWC, the higher the LCA colony density. 4 We conclude that drought stress-induced osmoregulation of plants varies with edge orientation and also that LCA may profit from changes in leaf quality in terms of an increased population density along edges, where plant individuals face higher drought stress levels.