title: Climatic Variables Do Not Directly Predict Spider Richness and Abundance in Semiarid Caatinga Vegetation, Brazil.
abstract: Spiders are abundant in tropical ecosystems and exert predatory pressure on a wide variety of invertebrate populations and also serve as prey for many others organisms, being part of complex interrelationships influenced directly and indirectly by a myriad of factors. We examined the influence of biotic (i.e., prey availability) and abiotic (i.e., temperature, precipitation, relative humidity, real evapotranspiration) factors on species richness and abundance during a two-year period in the semiarid Caatinga vegetation in northeastern Brazil. Data were analyzed through partial autocorrelation functions, cross correlations, and a path analysis. A total of 2522 spiders were collected with beating tray, pit-fall traps, and malaise traps, comprising 91 species and 34 families. Spider abundance peaked in the rainy season. Our results suggest that total invertebrate abundance has a direct influence on spider richness and abundance, whereas the effects of precipitation were mainly indirectly related to most spider assemblage parameters. The increase in vegetation cover with the rainy season in the Caatinga provides more breeding and foraging sites for spiders and stimulates their activities. Additionally, rainfall in arid and semiarid ecosystems stimulated the activity and reproduction of many herbivore and detritivore invertebrates dependent on plant biomass and necromass consumption, leading to an increase in spider prey availability.
authors: Universidade Federal do Piauí, Campus Amílcar Ferreira Sobral. BR 343, KM 3.5, Meladão. 64800-000, Floriano, PI, Brazil. Programa de Pós-graduação em Zoologia, Universidade Federal de Minas Gerais, Belo Horizonte - MG, Brazil. carvalho@ufpi.edu.br.
authors: Leonardo S
authors: LS
authors: Carvalho
authors: Departamento de Ecologia, CB, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN, Brazil.
authors: Nicholas
authors: N
authors: Sebastian
authors: Departamento de Ciências Biológicas, Centro de Ciências Agrárias, Universidade Federal da Paraíba, 58397-000, Areia, PB, Brazil.
authors: Helder F P
authors: HF
authors: Araújo
authors: Rua Arício Guimarães Fortes, Ed. Jardim da Atalaia, 826, apto. 401, 49037-060, Atalaia, Aracaju, SE, Brazil.
authors: Sidclay C
authors: SC
authors: Dias
authors: Departamento de Ecologia, CB, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN, Brazil.
authors: Eduardo
authors: E
authors: Venticinque
authors: Laboratório Especial de Coleções Zoológicas, Instituto Butantan. Avenida Vital Brasil 1500, 05503-900 - São Paulo, SP, Brazil.
authors: Antonio D
authors: AD
authors: Brescovit
authors: Laboratório de Termitologia, Departamento de Sistemática e Ecologia, CCEN, Universidade Federal da Paraíba, 58051-900, João Pessoa, PB, Brazil.
authors: Alexandre
authors: A
authors: Vasconcellos
mesh_terms: D000818:Animals; D044822:Biodiversity; D018533:Biomass; D001938:Brazil; D002980:Climate; D020387:Food Chain; D007448:Invertebrates; D011156:Population Density; D011891:Rain; D012621:Seasons; D013112:Spiders / Q000502:physiology*
keywords: assemblage structure; invertebrate; neotropical region; prey availability; seasonality