Macroinvertebrados associados a vriesea splitgerberi (mez) l.b. sm. & pitten. (1953) (bromeliaceae) em uma floresta de campinarana na Reserva Florestal Adolpho Ducke, Amazônia central

Abstract

Bromeliaceae is included in a group of plants called phytotelmata regarded as small water bodies retained in plant structures. These environments have a great capacity for water storage and supply of nutrients serving as breeding for a range of terrestrial and aquatic macroinvertebrates, where the immature forms are dominant, particularly the representatives of the order Diptera. Studies involving phytotelmata of bromeliads are still little studied in the Amazon region. Thus, in order to identify the entomofauna this, determining the functional groups of taxa and evaluating the influence of abiotic factors (volume, pH, temperature, electrical conductivity and height of the plant from the ground), morphometrics of plant (height, diameter, volume, number of leaves) over there the dry weight of organic matter in the water on the community associated with axils of Vriesea splitgerberi was studied. Was colected 80 epiphytic bromeliads located between 10 and 15m of soil, at the beginning and the end of the rainy season equivalent to the months of December/2006 and May/2007 respectively, in the area of campinarana forest in Reserva Florestal Adolpho Ducke, Manaus, Amazonas. The results showed 2,563 individuals, distributed in 42 taxa. Of these, the highest rates in richness and abundance of organisms were recorded for May/2007 (t-teste; t= -4.89, p= 0.000005; t-teste, t= -4.36; p= 0.000039 respectively). The families more abundant were Chironomidae (47.7%), Culicidae (16.4%), followed by Formicidae (11.1%), Scirtidae (5.46%) and Ceratopogonidae with 4.68%. Between the aquatic invertebrates the frequency of occurrence was higher in Polypedilum spp. (32.7%) 838 individuals, then Larsia sp. (61.25%), Scirtidae (58.75%), Culex (Microculex) stonei Lane & Whitman, 1943 (53.75%) and Culicoides sp. with 51.25%. The study used multiple regression to the abundance of macroinvertebrates with abiotic variables was significant (F4,75= 5.002; p= 0.001) but with the morphometric factors was not significant (p= 0.144). For richness of organisms, the multiple regression model was significant (F3,56=3. 568; p= 0.0101) with the abiotic factors, whose variable dry weight of organic matter in the water, was positively related (p= 0.04 ). However, with the morphometric variables was not significant (F4,75= 1.85; p= 0.128). The simple regressions performed for the plant height from the ground, showed no significance for abundance (r2= 0. 018; p= 0.225) and richness of macroinvertebrates collected (r2=0. 001; p=0.745), because to the small range of variation. The variable dry weight of organic matter in water was the only positively influencing the relationship of abundance of Ceratopogonidae (p= 0.026), Culicidae (p= 0.0003) and Polypedilum spp. (p= 0.049) presented in multiple regression models. We considered three trophic levels, and Bromeliagrion rehni Garrison, 2005, the top predator in this system, and 10 (ten) the amount of categories functional, which was the most abundant of collectors-filterings represented by culicids and chironomid, probably explained by heavy suspension of sediment in the water tank of bromeliads. Thus, the availability of food resources is the factor that determines and provides the community of macroinvertebrates associated with phytotelma bromeliads V. splitgerberi.