When partitioning is not an option: Resource availability predicts intraguild interactions in two isolated Amazonian primate assemblages

• Published in: Biotropica 2023-07, Vol.55 (4), p.839-848
• Main Authors: Cavalcante, Thiago, Mourthé, Ítalo, Barnett, Adrian A., Bicca‐Marques, Júlio César
• Format: Article
• Language: English
• Subjects: agonistic interactions; assemblage structure; Atelidae; Availability; Carrying capacity; Coexistence; Feeding; Fruits; habitat partitioning; Habitats; High frequency; interspecific interactions; Interspecific relationships; Population density; Primates; Resource availability; resource competition; Temporal variations
• ISSN: 0006-3606; 1744-7429
• DOI: 10.1111/btp.13233

Assemblage structure and acquisition of high‐value resources will usually be affected by changes in resource availability and differential competitive abilities of assemblage members. In fragmented habitats where carrying capacity limits are exceeded due to high population densities and biomass, interspecific interactions can be expected to occur at a high frequency, potentially turning into an important cost for coexistence. We studied assemblage‐ and guild‐level patterns of interspecific interactions in two highly diverse isolated primate assemblages in southern Amazonia. Specifically, we assessed the effects of temporal variation in fruit availability on the rates of interspecific interactions between gray woolly monkeys (Lagothrix lagotricha cana), one of the largest tree‐dwelling mammals of the Amazon forests, and nine syntopic primate species. We found that fruit availability positively predicted rate of intraguild interactions in contrast to overall assemblage interaction rate. We did not find statistical evidence for the effect of fruit availability on the assemblage rates of type‐dependent (i.e., agonistic or non‐agonistic) and context‐dependent (i.e., feeding or non‐feeding) interactions. However, there was a clear trend toward increased feeding‐related and agonistic‐related interactions as fruit availability increased, with agonistic interactions mostly occurring at guild‐level. These results provide support for a significant role of fruit availability in structuring spatial–temporal intraguild interactions at our study sites. Costly interspecific interactions and spatial habitat overlap can be expected to occur at a high frequency in highly diverse assemblages living in human‐modified landscapes, which in turn, can have potentially negative impacts to the species involved. We investigated the effects of fruit availability on the rates of interactions between gray woolly monkeys (Lagothrix lagotricha cana) and nine syntopic primate species in two isolated primate assemblages in southern Amazonia. We found that fruit availability positively predicted rate of intraguild interactions in contrast to overall assemblage interaction rate, providing support for a significant role of fruit availability in shaping spatial–temporal intraguild interactions at our study sites. Species living in human‐modified landscapes may experience costly interspecific interactions and spatial habitat overlap at higher frequencies than previously recognized, which can lea