Agricultural simplification continues to expand at the expense of more diverse forms of agriculture. This simplification, for example, in the form of intensively managed monocultures, poses a risk to keeping the world within safe and just Earth system boundaries. Here, we estimated how agricultural diversification simultaneously affects social and environmental outcomes. Drawing from 24 studies in 11 countries across 2655 farms, we show how five diversification strategies focusing on livestock, crops, soils, noncrop plantings, and water conservation benefit social (e.g., human well-being, yields, and food security) and environmental (e.g., biodiversity, ecosystem services, and reduced environmental externalities) outcomes. We found that applying multiple diversification strategies creates more positive outcomes than individual management strategies alone. To realize these benefits, well-designed policies are needed to incentivize the adoption of multiple diversification strategies in unison.

Terrestrial animal biodiversity is increasingly being lost because of land-use change^1,2. However, functional and energetic consequences aboveground and belowground and across trophic levels in megadiverse tropical ecosystems remain largely unknown. To fill this gap, we assessed changes in energy fluxes across ‘green’ aboveground (canopy arthropods and birds) and ‘brown’ belowground (soil arthropods and earthworms) animal food webs in tropical rainforests and plantations in Sumatra, Indonesia. Our results showed that most of the energy in rainforests is channelled to the belowground animal food web. Oil palm and rubber plantations had similar or, in the case of rubber agroforest, higher total animal energy fluxes compared to rainforest but the key energetic nodes were distinctly different: in rainforest more than 90% of the total animal energy flux was channelled by arthropods in soil and canopy, whereas in plantations more than 50% of the energy was allocated to annelids (earthworms). Land-use change led to a consistent decline in multitrophic energy flux aboveground, whereas belowground food webs responded with reduced energy flux to higher trophic levels, down to −90%, and with shifts from slow (fungal) to fast (bacterial) energy channels and from faeces production towards consumption of soil organic matter. This coincides with previously reported soil carbon stock depletion³. Here we show that well-documented animal biodiversity declines with tropical land-use change^4–6 are associated with vast energetic and functional restructuring in food webs across aboveground and belowground ecosystem compartments.

Dung beetles are a functionally important component of most terrestrial ecosystems, but communities change with habitat disturbance and deforestation. In this study, we tested if dung beetle ensembles on dung of introduced cattle and of the endemic anoa, a small buffalo, are affected differentially by habitat disturbance. Therefore, we exposed 10 pitfall traps, five baited with anoa and five baited with cattle dung, per site in six habitat types ranging from natural and selectively logged rain forest to three types of agroforestry system (characterized by different management intensity) and open areas (n = 4 replicate sites per habitat type) at the margin of Lore Lindu National Park, Central Sulawesi, Indonesia. We found 28 species, 43% of which were endemic to Sulawesi. Species richness, abundance and biomass declined from natural forest towards open area. Large-bodied species appeared to be more sensitive to habitat disturbance and the ratio of large to small-sized dung beetles declined with land-use intensity. Although selectively logged forest and cocoa agroforestry systems had lower species richness compared with natural forest, they appeared to maintain a high portion of species originally inhabiting forest sites. The similarity of dung beetle ensembles recorded at forest and agroforestry sites reflects the high similarity of some habitat variables (e.g. vegetation structure and microclimate) between both habitat types compared with open areas. Species richness and abundances as well as species composition, which was characterized by decreases in mean body size, changed with land-use intensity, indicating that dung type is less important than habitat type for determining ensemble structure of these Indonesian dung beetles.

The Rice Weevil, Sitophilus oryzae (L.), and the maize weevil, S. zeamais Motschulsky, are sibling species of grain weevils that are usually distinguished by grain preferences and subtle differences in morphology. Previous findings of successful laboratory hybridization, genetic similarity of allozymes and chromosomes, and identity of aggregation pheromones raised questions about the validity of S. oryzae and S. zeamais as reproductively isolated biological species. We used molecular techniques to test the hypothesis that individuals assigned as S. oryzae or S. zeamais by morphological criteria represent members of 2 distinct gene pools, and hence are reproductively isolated species. Weevils from 18 different localities, which were collected from Africa, Australia, Asia, the south Pacific, and North America, were studied. All individuals were scored for the presence or absence of morphological characters that have been used historically for species determination. In most cases, determinations for the same individual were not consistent, depending on the morphological character used. The polymerase chain reaction (PCR) was used on the same specimens to analyze randomly amplified polymorphic DNA (RAPD-PCR) markers and to amplify selectively regions of mitochondrial DNA for analysis of restriction site polymorphisms with restriction endonucleases (RFLP-PCR). Both methods yielded markers that were consistently associated with either presence or absence of specific genitalic characters in both males and females. This correlation of molecular markers with genitalic morphotypes was consistent in all specimens studied, whether collected sympatrically from the same farms or from widely separated geographic populations, and supports a model of 2 reproductively isolated species. Other morphological characters involving pronotal punctures proved unreliable as correlates with genetic markers and are not useful for species diagnosis.