Summary1. Throughout much of the tropics, habitat loss is increasing and intensifying on the unprotected land surrounding conservation areas. The influence of these land-use changes on biodiversity is poorly understood. This study used data on dung beetles, a taxonomic group widely acknowledged to be an effective ecological indicator of anthropogenic disturbance, to evaluate temporal changes in diversity inside a natural protected area. 2. Using data from quantitative sampling events over the last 35 years along with an exhaustive review of the information available in museums and the literature, we present evidence suggesting that the dung beetles community structure has shifted dramatically over time at La Selva Biological Station, Costa Rica. 3. To date, 50 dung beetle species have been reported from La Selva. Of these, 10 (20%) were consistently collected within the study timeframe while 21 species (42%) were uncommon. Our results indicate a tendency toward decreasing species richness and changes in species composition over time. 4. Analysis of the community structure revealed a decrease in diversity (H ′ ), an increase in dominance (D) and a decrease in evenness (J) over the 35-year period; all of which can be linked to an increase in the dominance of one species ( Onthophagus acuminatus ). These changes were also reflected in the proportional abundance of major species guilds. 5. Synthesis and applications . Despite the relatively low human impact within La Selva, this study suggests that the dung beetle community has changed as result of habitat loss in the surrounding landscape and the progressive increasing isolation of the reserve over the last 35 years. Our findings, together with studies of other biota in the reserve, indicate a worrying decline in the conservation value of La Selva in recent decades. This shift in the diversity and composition of native forest biota needs to be taken into account in future studies that continue to rely on La Selva as providing an intact baseline for comparative research. More importantly, we suggest that the size of the reserve may need to be increased if its ecological integrity is to be restored. This study provides further evidence that isolated protected areas may often fail to safeguard biodiversity in the long term, and that to be viable, conservation strategies urgently need to adopt a wider landscape perspective.

This paper is an analysis of the distribution of areas of high species richness and endemicity based on dung beetles living in the different Holdridge life-zones of Costa Rica by using a geographic information system (GIS). Endemism was examined in relation to whether the species were shared with Nicaragua and/or Panama, or if they were strictly Costa Rican. The species composition of dung beetle distributions in the sampling areas and life-zones was evaluated. Species distribution was also analyzed in relation to altitudinal levels. The species richness and endemicity maps served as a base for doing a gap analysis and defining four different levels of high priority conservation areas. We also investigated what percentage of these priority areas is under some type of protection or conservation scheme and which of these areas should be enlarged. Also considered is the feasibility that these areas under protection have for enlargement, considering possible problems and interactions with present land-use. We include a list of all the recorded dung beetle species for Costa Rica, as well as their presence in the different Holdridge life-zones and their endemicity status. This study clearly demonstrates the need to include insects in biodiversity-endemicity studies because different and more detailed results are obtained in relation to vertebrate and plant-based studies.

No abstract

Responses to microhabitat are often neglected when ecologists sample animal indicator groups. Microhabitats may be particularly influential in non-passive biodiversity sampling methods, such as baited traps or light traps, and for certain taxonomic groups which respond to fine scale environmental variation, such as insects. Here we test the effects of microhabitat on measures of species diversity, guild structure and biomass of dung beetles, a widely used ecological indicator taxon. We demonstrate that choice of trap placement influences dung beetle functional guild structure and species diversity. We found that locally measured environmental variables were unable to fully explain trap-based differences in species diversity metrics or microhabitat specialism of functional guilds. To compare the effects of habitat degradation on biodiversity across multiple sites, sampling protocols must be standardized and scale-relevant. Our work highlights the importance of considering microhabitat scale responses of indicator taxa and designing robust sampling protocols which account for variation in microhabitats during trap placement. We suggest that this can be achieved either through standardization of microhabitat or through better efforts to record relevant environmental variables that can be incorporated into analyses to account for microhabitat effects. This is especially important when rapidly assessing the consequences of human activity on biodiversity loss and associated ecosystem function and services.

The following new species of geotrupids and scarabs from Costa Rica and Panama are described: Athyreus gulesserianinew species, Ateuchus alutacius new species (the first recorded brachypterous Ateuchus species), Coprophanaeus geph-yra new species, Deltochilum acanthus new species, and Onthophagus turgidus new species. The following two speciesof Coprophanaeus are revalidated: C. kohlmanni Arnaud and C. uhleri Malý & Pokorný. Illustrations of the dorsal habitus of the new species are provided, as well as distribution maps for all species.