ABSTRACT
The development of efficient sampling protocols is an essential prerequisite to evaluate and identify priority conservation areas. There are few protocols for fauna inventory and monitoring in wide geographical scales for the tropics, where the complexity of communities and high biodiversity levels, make the implementation of efficient protocols more difficult. We proposed here a simple strategy to optimize the capture of dung beetles, applied to sampling with baited traps and generalizable to other sampling methods. We analyzed data from eight transects sampled between 2006-2008 with the aim to develop an uniform sampling design, that allows to confidently estimate species richness, abundance and composition at wide geographical scales. We examined four characteristics of any sampling design that affect the effectiveness of the sampling effort: the number of traps, sampling duration, type and proportion of bait, and spatial arrangement of the traps along transects. We used species accumulation curves, rank-abundance plots, indicator species analysis, and multivariate correlograms. We captured 40 337 individuals (115 species/morphospecies of 23 genera). Most species were attracted by both dung and carrion, but two thirds had greater relative abundance in traps baited with human dung. Different aspects of the sampling design influenced each diversity attribute in different ways. To obtain reliable richness estimates, the number of traps was the most important aspect. Accurate abundance estimates were obtained when the sampling period was increased, while the spatial arrangement of traps was determinant to capture the species composition pattern. An optimum sampling strategy for accurate estimates of richness, abundance and diversity should: (1) set 50-70 traps to maximize the number of species detected, (2) get samples during 48-72 hours and set trap groups along the transect to reliably estimate species abundance, (3) set traps in groups of at least 10 traps to suitably record the local species composition, and (4) separate trap groups by a distance greater than 5-10km to avoid spatial autocorrelation. For the evaluation of other sampling protocols we recommend to, first, identify the elements of sampling design that could affect the sampled effort (the number of traps, sampling duration, type and proportion of bait) and their spatial distribution (spatial arrangement of the traps) and then, to evaluate how they affect richness, abundance and species composition estimates.
El presente trabajo propone una estrategia sencilla de optimización del diseño muestreal para escarabajos coprófagos que puede ser aplicada a muestreos basados en trampas atrayentes en amplias escalas geográficas y generalizada a otros tipos de muestreo. Para ello, analizamos muestras colectadas en ocho localidades con hábitats contrastantes y diferentes características del muestreo entre 2006-2008. Se capturaron 40 337 ejemplares (115 especies/ morfoespecies, de 23 géneros). El número de trampas fue el aspecto del muestreo más importante para obtener estimadores de riqueza confiable. El tiempo de muestreo para generar estimadores precisos de abundancia y la disposición espacial de las trampas para captar adecuadamente la diferencias en composición entre localidades. Sugerimos que una estrategia óptima de muestreo para obtener estimadores precisos de riqueza, abundancia y diversidad consistiría en: (1) colocar 50-70 trampas para maximizar el número de especies detectadas, (2) muestrear entre 48 y 72 hrs y colocar grupos de trampas a lo largo de un transecto para estimar confiablemente la abundancia de las especies, (3) colocar siete grupos de al menos 10 trampas para registrar adecuadamente la composición de cada localidad y (4) separar los grupos de trampas por distancias mayores a 5-10km para minimizar la autocorrelación espacial.
Subject(s)
Animals , Humans , Coleoptera/classification , Biodiversity , Entomology/methods , Entomology/standards , Population Density , VenezuelaABSTRACT
O Brasil abriga cerca de 15 por cento da riqueza de morcegos do planeta, e grande parte desta riqueza está presente no bioma Amazônia. Apresentamos aqui uma compilação atualizada das espécies de morcegos da Amazônia Legal Brasileira, com registros formais de 146 espécies, distribuídas em nove famílias, e 64 gêneros. Pelo menos 46 destas espécies têm, até o momento, a ocorrência restrita ao bioma amazônico. O Pará é o estado com o maior número de espécies registradas (120), enquanto que a porção amazônica do Maranhão apresenta apenas 21 espécies. Nove espécies foram registradas em todos os estados amazônicos e 28 são conhecidas em apenas um estado. A lista de espécies de morcegos para a região não está esgotada e é bastante plausível que a Amazônia Brasileira contenha mais de 160 espécies de morcegos. Apontamos áreas prioritárias para a realização de inventários para morcegos na região, e discutimos alguns fatores que podem contribuir para o aumento do conhecimento da quiropterofauna amazônica.
Brazil holds nearly 15 percent of world's bat species richness, and most of it is present in the Amazonian biome. Here we present an updated compilation of bat species for the Brazilian Amazonia, with records of 146 species, belonging to nine families and 64 genera. At least 46 of those species are currently restricted to the Amazonian biome. Pará State is the species richest (120 spp.) and the Amazonian portion of Maranhão the least (21 spp.). Nine species were recorded in all the Amazonian States, and 28 are restricted to a single state. The species list for the region is not yet completed and is very likely that the Brazilian Amazonia holds more than 160 species of bats. We indicated priority areas for inventories in the region, and discuss some factors that can contribute to a further increase in the knwoledge of the regional bat fauna.