ABSTRACT
BACKGROUND: Land-use is a major driver of changes in biodiversity worldwide, but studies have overwhelmingly focused on above-ground taxa: the effects on soil biodiversity are less well known, despite the importance of soil organisms in ecosystem functioning. We modelled data from a global biodiversity database to compare how the abundance of soil-dwelling and above-ground organisms responded to land use and soil properties. RESULTS: We found that land use affects overall abundance differently in soil and above-ground assemblages. The abundance of soil organisms was markedly lower in cropland and plantation habitats than in primary vegetation and pasture. Soil properties influenced the abundance of soil biota in ways that differed among land uses, suggesting they shape both abundance and its response to land use. CONCLUSIONS: Our results caution against assuming models or indicators derived from above-ground data can apply to soil assemblages and highlight the potential value of incorporating soil properties into biodiversity models.
Subject(s)
Ecosystem , Soil , Biodiversity , Soil Microbiology , BiotaABSTRACT
The Neotropical genus Austrohahnia Mello-Leitão, 1942 is revised, comprising four species from Argentina. The genus is here transferred to the subfamily Hahniinae Bertkau, 1878 from Cybaeolinae Lehtinen, 1967. Austrohahnia is diagnosed by a single synapomorphy, short setae ventrally on the abdomen, in immature as well as adult stages. The type species A. praestans Mello-Leitão, 1942 is redescribed. Austrohahnia catleyi new species is described and illustrated based both sexes from the alder forests of northwestern Argentina. Austrohahnia melloleitaoi (Schiapelli & Gerschman, 1942) new combination was transferred from Hahnia C.L. Koch, 1841, the male is described and illustrated for the first time, and the female is redescribed. Austrohahnia isophthalma (Mello-Leitão, 1941) new combination is also transferred from Hahnia and considered a nomen dubium. New geographic records of studied species are provided.
Subject(s)
Spiders/classification , Animal Distribution , Animal Structures/anatomy & histology , Animal Structures/growth & development , Animals , Argentina , Body Size , Ecosystem , Female , Forests , Male , Organ Size , Spiders/anatomy & histology , Spiders/growth & developmentABSTRACT
The identification of high-performance indicator taxa that combine practical feasibility and ecological value requires an understanding of the costs and benefits of surveying different taxa. We present a generic and novel framework for identifying such taxa, and illustrate our approach using a large-scale assessment of 14 different higher taxa across three forest types in the Brazilian Amazon, estimating both the standardized survey cost and the ecological and biodiversity indicator value for each taxon. Survey costs varied by three orders of magnitude, and dung beetles and birds were identified as especially suitable for evaluating and monitoring the ecological consequences of habitat change in our study region. However, an exclusive focus on such taxa occurs at the expense of understanding patterns of diversity in other groups. To improve the cost-effectiveness of biodiversity research we encourage a combination of clearer research goals and the use of an objective evidence-based approach to selecting study taxa.