Species interactions, not Richness: How does long-term pastoral land use alter Mediterranean mammal communities?

Pastoralism, a common land use worldwide, plays a significant ecological role in Mediterranean ecosystems, where it has been present for millennia. However, its long-term effects on mammal communities, community composition, and interspecific interactions are not fully understood. We carried out a camera-trap study at four nature reserves in northern Israel, comparing medium-sized mammal communities between paired grazed (pastoral) and non-pastoral habitats. We estimated that pastoralism acts as an environmental driver, possibly through food subsidies or landscape opening. Using generalized linear mixed models, non-metric multidimensional scaling, and piecewise structural equation modeling, we examined species richness, community composition, and both spatial and temporal interspecific associations. Our findings showed no significant differences in species richness or community composition between pastoral and non-pastoral areas. Nonetheless, the structure of mammalian interaction networks and patterns of temporal associations were notably affected by habitat type (pastoral vs. non-pastoral). Non-pastoral habitats were characterized by clear ecological networks and temporal partitioning, whereas in pastoral habitats, these patterns were altered, with weakened or reversed interspecies relationships and increased temporal overlap among most abundant species such as the golden jackal ( Canis aureus ) and the wild boar ( Sus scrofa ). These results suggest that long-term pastoralism, while not affecting species richness or community composition, can reorganize mammalian communities through altered biological interactions. We recommend that conservation efforts in protected areas focus on maintaining landscape mosaics with non-pastoral refuges to preserve heterogeneity in interaction networks, acknowledging the widespread and context-specific influence of pastoral land use on ecosystem functions.