Preditores de paisagem da herbivoria em cultivos de subsistência da caatinga

Abstract

Agriculture plays a fundamental role in food security, but its expansion into natural ecosystems entails biodiversity losses and changes in ecological processes, directly affecting productivity. In tropical and semiarid regions, such as the Caatinga, these transformations have relevant implications, since environmental fragility, marked by water scarcity and human pressure, imposes challenges to the maintenance of subsistence crops. In this context, understanding how landscape attributes, such as the proportion of conserved areas, the degree of fragmentation, and the diversity of land uses, influence interactions between plants and herbivores is essential to guide more sustainable agricultural practices. This study investigated herbivory in maize and bean crops in the Cariri region of Paraíba, relating the frequency and magnitude of foliar and reproductive damage with landscape predictors in order to relate these data with the predictors of the local landscape. Seventeen properties were evaluated, where damages were recorded on leaves and fruits of both crops. It was observed that the density of forest fragments was the most consistent predictor, being associated with the increase in herbivory frequency, while forest cover and human impact on the matrix showed variable effects between leaves and fruits, sometimes positive, sometimes negative. In maize, fragmentation was linked to a higher frequency of foliar damage, and the ears responded to multiple landscape factors, including forest cover and anthropization. In beans, more conserved areas favored damage on leaves but reduced the incidence of arthropods in pods, suggesting that native vegetation plays an ambivalent role by providing both refuge for herbivores and support for natural enemies. Despite these variations, the average magnitude of herbivory was low (around 2%), not compromising the productivity of family farms. Thus, herbivory can be understood as a natural component of agroecosystems, whose impact is limited in small-scale crops and can be managed through strategies that integrate conservation and traditional agricultural practices. The results show that landscape predictors, especially fragmentation, are determining factors in the modulation of ecological interactions in the Caatinga. Therefore, the maintenance and restoration of native areas around crops represent important strategies to reconcile agricultural production and environmental conservation in semiarid regions.