Phenotypic variability and developmental instability in rodents from different agricultural farming systems: Organic vs. conventional

Abstract

Contrary to conventional agriculture, organic farming, where agrochemicals are entirely avoided, is considered more environmentally friendly. Numerous studies undertaken in agroecosystems have found that the intensification of agriculture has a negative impact on some small mammals species. In this study, we used two morphological indicators to evaluate the impact of agriculture intensification. Phenotypic variability and fluctuating asymmetry (FA- development instability proxy) have been widely used as morphological indicators of developmental stress. We implemented geometric morphometric methods to assess the influence of different agricultural farming systems on three rodent species. We hypothesize that conventional farming produces more stressful conditions than organic farming affecting species susceptible to agricultural intensification. We predicted that Akodon azarae, negatively affected by landscape simplification and more dependent on habitat quality, will show higher levels of phenotypic variation and greater FA in conventional farming. Whereas, Calomys musculinus and C. laucha, unaffected by agricultural intensification, will not show differences between farming systems. Akodon azarae exhibited higher phenotypic variability in conventional farms, while C. musculinus had no difference between farming systems. Contrarily, C. laucha exhibited higher values in conventional farms. Regarding FA, both Calomys species showed no differences between farming systems. Females of A. azarae tend to have higher FA values in conventional farming. Our results suggest that the effect of agricultural farming systems would vary according to the species, where the species most dependent on habitat quality would be more affected by intensive agriculture.