Studies on elevation diversity gradients have covered a large number of taxa and regions throughout the world; however, studies of freshwater fish are scarce and restricted to examining their changes along a specific gradient. These studies have reported a monotonic decrease in species richness with increasing elevation, but ignore the high taxonomic differentiation of each headwater assemblage that may generate high β-diversity among them. Here, we analyzed how fish assemblages vary with elevation among regional elevation bands, and how these changes are related to four environmental clines and to changes in the distribution, habitat use, and the morphology of fish species. Using a standardized field sampling technique, we assessed three different diversity and two structural assemblage measures across six regional elevation bands located in the northern Andes (Colombia). Each species was assigned to a functional group based on its body shape, habitat use, morphological, and/or behavioral adaptations. Additionally, at each sampling site, we measured four environmental variables. Our analyses showed: (1) After a monotonic decrease in species richness, we detected an increase in richness in the upper part of the gradient; (2) diversity patterns vary depending on the diversity measure used; (3) diversity patterns can be attributed to changes in species distribution and in the richness and proportions of functional groups along the regional elevation gradient; and (4) diversity patterns and changes in functional groups are highly correlated with variations in environmental variables, which also vary with elevation. These results suggest a novel pattern of variation in species richness with elevation: Species richness increases at the headwaters of the northern Andes owing to the cumulative number of endemic species there. This highlights the need for large-scale studies and has important implications for the aquatic conservation of the region.

Balancing the production of food, particularly meat, with preserving biodiversity and maintaining ecosystem services is a major societal challenge. Research into the contrasting strategies of land sparing and land sharing has suggested that land sparing-combining high-yield agriculture with the protection or restoration of natural habitats on nonfarmed land-will have lower environmental impacts than other strategies. Ecosystems with long histories of habitat disturbance, however, could be resilient to low-yield agriculture and thus fare better under land sharing. Using a wider suite of species (birds, dung beetles and trees) and a wider range of livestock-production systems than previous studies, we investigated the probable impacts of different land-use strategies on biodiversity and aboveground carbon stocks in the Yucatán Peninsula, Mexico-a region with a long history of habitat disturbance. By modelling the production of multiple products from interdependent land uses, we found that land sparing would allow larger estimated populations of most species and larger carbon stocks to persist than would land sharing or any intermediate strategy. This result held across all agricultural production targets despite the history of disturbance and despite species richness in low- and medium-yielding agriculture being not much lower than that in natural habitats. This highlights the importance, in evaluating the biodiversity impacts of land use, of measuring population densities of individual species, rather than simple species richness. The benefits of land sparing for both biodiversity and carbon storage suggest that safeguarding natural habitats for biodiversity protection and carbon storage alongside promoting areas of high-yield cattle production would be desirable. However, delivering such landscapes will probably require the explicit linkage of livestock yield increases with habitat protection or restoration, as well as a deeper understanding of the long-term sustainability of yields, and research into how other societal outcomes vary across land-use strategies.

Abstract1. As tropical cattle ranching continues to expand, successful conservation will require an improved understanding of the relative impacts of different livestock systems and landscape structure on biodiversity. Here, we provide the first empirical and multi-scale assessment of the relative effects of livestock intensification and landscape structure on biodiversity in the threatened tropical dry forests of Mesoamerica.2. We used a dataset of dung beetles (169,372 individuals from 33 species) collected from 20 1-km 2 landscapes, ranging from zero-yielding forest sites to high-yield cattle ranches and maize farms, to investigate the relative effect of livestock intensification (net cattle production; macrocyclic lactone use; annual dung production) and landscape structure (landscape composition and configuration) at multiple spatial scales on different attributes of dung beetle communities using a multi-model averaging approach.3. Dung beetle species richness, biomass and composition were more strongly related to landscape structure than to livestock intensification.4. Forest cover was the best predictor of dung beetle assemblages, being positively related to species diversity and biomass across multiple spatial scales. The use of macrocyclic lactones was strong and negatively related to dung beetle communities at the local scale. Synthesis and applications:Maximising forest protection through a "land sparing" strategy is likely to be the best strategy for reducing negative impacts of cattle farming on Neotropical dung beetle communities. However, increasing or maintaining yields while reducing agrochemical inputs will be important for conserving onfarm biodiversity and the ecosystem services that dung beetles provide in livestock-dominated landscapes. K E Y W O R D Scattle ranching, dung beetles, food production, forest protection, land sparing, livestockdominated landscapes, spatial heterogeneity, species richness, tropical biodiversity, tropical dry forest

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Questions Climate change is dramatically altering rainfall patterns and species distribution around the world. However, little is known about how rainfall reduction may affect plant–herbivore interactions that are crucial to the of input energy and nutrients into terrestrial ecosystems. Following Coley’s growth rate hypothesis, we assessed whether rainfall reduction in a seasonally dry tropical forest decreases community‐level herbivory owing to water shortage in drier areas. Location Catimbau National Park, Northeast Brazil. Methods We sampled 16 herb communities along a rainfall gradient (564–917 mm). Using digital photographs, we monitored for 3 weeks the frequency, magnitude and type (feeding guild) of insect damage on young, fully expanded, short‐lived leaves (lifespan <1 month). We related herbivory levels to local rainfall and examined potential confounding effects of herb abundance, richness and floristic composition on such relationships. Results We monitored 290 leaves from 202 plants belonging to 28 species. About one‐third of the leaves and six species escaped from herbivory. Leaf‐chewing insects were the most frequent herbivores, attacking 17 species, 44% ± 15% of the leaves and removing the same amount of foliar tissue as all the other insects combined removed (sap‐sucking, rasping, leaf‐mining and ‘unknown’). Contrary to expectations, foliar damage accumulated more in drier areas following the increase in the frequency of leaf‐chewing damage. In addition, frequency and magnitude of herbivory did not vary with herb abundance and richness and were weakly influenced by floristic composition. Conclusions Our findings suggest that rainfall underlies community‐level herbivory by mechanisms not related to plant availability, identity and diversity. Based on recent evidence that aridity favours leaf‐chewing proliferation in the study region, we hypothesize that rainfall reduction may weaken the top‐down control of herbivores, increasing folivory pressure on herbs. If prolonged droughts become more frequent in the coming decades, plant–herbivore interactions may be altered permanently.

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1. Urbanisation causes important losses in biodiversity and ecosystem of animals. To test whether these negative effects are preceded by unhealthy individuals in urban populations, we evaluated the effects of urbanisation on the abundance and physical condition of the dung beetle Dichotomius guaribensis, an endemic species of the Brazilian Atlantic Forest.2. We sampled beetles in nine forest fragments with different urbanisation degrees, embedded in the urban matrix of the city of João Pessoa. Besides testing the abundance in each fragment, we quantified four indicators of physical condition in males and females: body size, body mass, energetic condition, and mite load.3. Females tended to be larger, and to have less lipid mass and more mites than males. Urbanisation had no effect on beetle abundance, but it negatively affected body mass and lipid content in males, but not females, revealing different sensitivities for both sexes. Body size and mite load were not affected by urbanisation in males or females. Fragment size had no effect on beetle abundance and physical condition in both sexes, suggesting that urbanisation has a greater impact than fragment size on beetle individual condition.4. In this study, we show that individual deterioration precedes population declines in disturbed environments, and our study opens new insights into the proximate causes that leads to the loss of biodiversity and ecosystem services in urbanised regions.

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