Pesticides are integral to mainstream agriculture. Consequently, many non-target organisms that rely on agricultural landscapes may be exposed to them. Vertebrate non-target species can be exposed to pesticides via their food webs that may include soil and soil-dwelling organisms, like earthworms. Despite long-term and widespread use, direct links between agricultural practices and pesticide exposure in soil organisms remain understudied. This study screened for 648 current-use pesticides and quantified their presence in soils and whole-earthworm samples derived from farmlands in southwest Friesland, the Netherlands. In June-July 2020, 26 fields differing in crop type and agricultural management practices were sampled (4 bulb, 7 corn, 8 grass, and 7 old grass fields). Historical land-use and management practices were reconstructed through interviews and farmer data collection. Sampling revealed that insecticides were rarely detected. Fungicide concentrations were highest in bulb field soils, while the herbicide metabolite terbuthylazine-2-hydroxy dominated corn field soils. Grassland soils revealed elevated fungicide levels corresponding with past bulb cultivation, indicating long-term persistence in soil. Soils from bulb fields were associated with prothioconazole-desthio, metolachlor, and metamitron, whereas corn-field soils were associated with foramsulfuron, fluroxypyr-1-methylheptylester, and fluroxypyr. Bixafen was associated with old-grassland soils. Pesticide residues in whole-earthworm samples were generally consistent with the pesticide profiles observed in soil. These results demonstrate that crop type and management practice structure pesticide residue profiles in soil and earthworms, indicating that earthworm-consuming wildlife may be exposed to these compounds through their diet.
Biodiversity conservation is challenging in the current pace of globalization, and requires an optimum model which maintains balance between development and conservation. Traditional agricultural landscapes are increasingly recognized as critical components of conservation, yet their capacity to sustain multiple dimensions of biodiversity remains poorly quantified, particularly in complex mountain systems. We assessed taxonomic (TD), functional (FD), and phylogenetic diversity (PD) of bird communities across five traditional agricultural systems: terrace rice cultivation (TRC), tea cultivation system (TCS), large cardamom-based agroforestry system (LCAS), farm-based agroforestry system (FAS), and agropastoral system (AP) along with corresponding adjacent natural forests in the Eastern Himalaya, an agrobiodiversity hotspot. Using standardized, multi-season bird samplings across 42 transects spanning a broad elevational gradient (772–3948 m), we recorded 9622 individuals representing 239 species and quantified ecological traits and evolutionary relationships to capture multidimensional diversity patterns. FAS and LCAS maintained high taxonomic and several components of functional diversity, in some cases comparable to or exceeding corresponding adjacent natural forests, whereas TRC and TCS showed reductions in taxonomic and/or multiple functional diversity metrics. Phylogenetic responses were more system-specific: TRC and TCS showed broadly comparable phylogenetic structure to the adjacent natural forests, whereas FAS exhibited significant phylogenetic clustering and lower ses MPD than its corresponding natural forest. AP also showed phylogenetic clustering relative to null expectations. Integrating these dimensions, the composite diversity index provided a comparative synthesis of multidimensional bird diversity, with FAS and LCAS exhibiting the highest mean values while revealing distinct biodiversity patterns among systems. Our findings demonstrate that traditional agricultural systems can make important and complementary contributions to maintaining multiple dimensions of bird diversity, although their conservation significance varies among systems and biodiversity dimensions. These findings emphasize the importance of system-specific conservation and land-use strategies that maintain traditional agricultural landscapes alongside natural forests in environmentally heterogeneous mountain regions.
Rising extreme climate events threaten agricultural production and food security. Climate adaptation strategies that enhance soil health are key to strengthening the stability and resilience of agricultural systems. This study reveals how crop diversification influences soil health functions and yield stability, by combining soil, yield, and climate data from thirteen farmer-led experiments in southern Brazil, a region highly exposed to climate variability. Twelve soil health indicators were integrated into four latent functions via factor analysis (79% of total variance explained) and linked to crop diversification, soil texture, and crop yield through structural equation modeling (~76% of variance explained in crop yield). Crop diversification, particularly combined crop rotation and cover crop mixtures, were positively associated with soil water storage independently of soil texture (β = 0.41). Among the four soil health functions, biochemical regulation of soil processes was the most significantly linked to crop yield (R²m = 0.31). Yield instability was the strongest direct predictor of crop yield (β = −0.61). On average, systems integrating crop rotation with multispecies cover crops achieved yields 1.76 times higher than the state average, and with markedly lower instability (24%) than conventional or single-practice systems (1.08 times the average; 33–39% instability, respectively). These findings identify yield stability as a key component of climate adaptation, and support integrated crop diversification as a promising strategy for regenerative agriculture and climate policy in Brazil.
Agricultural intensification is a major driver of farmland biodiversity loss. In Chinese smallholder systems, intensification involves increased insecticide use and farmland edge sealing, i.e. the transformation of vegetated field margins into concrete borders. However, the effects of these stressors on important natural enemies of crop pests like spiders remain unknown. We investigated how insecticide use and edge sealing affect spider assemblages along a gradient of landscape-scale semi-natural habitat cover across 55 fields comprising three main crops (maize, rice and tobacco) in a southern Chinese smallholder farming system. Farmland edge sealing reduced spider richness and functional diversity across all crops, while increasing insecticide use decreased spider densities. The stressors imposed different trait-based filters on spider assemblages: Under edge sealing, spider assemblages became on average smaller with fewer active hunters, while assemblages became on average larger with fewer passive hunters and good dispersers under increased insecticide use. Increasing landscape semi-natural habitat cover benefitted the functional diversity of spiders, indicating that offsetting the functional homogenization caused by edge sealing would require a 29.2% increase within 400 m. We demonstrate that farmland edge sealing and increased insecticide use are detrimental to spider numbers and the composition of spider assemblages, which may ultimately threaten natural pest regulation. Mitigating species losses caused by edge sealing with semi-natural habitats is unfeasible as it requires the dedication of large areas. We thus see a pressing need to reduce insecticide use and halt field margin conversion to conserve the functionality of farmland spider assemblages.
