Macroinvertebrados associados à Vriesea friburgensis Mez (bromeliaceae) em floresta ribeirinha, Santa Maria, RS, Brasil

Abstract

The studies on bromeliad fauna are spread more and more, not just due importance in the knowledge about animal diversity, but mainly thanks to the active ecological dynamics in these systems, since their basic rules could be applied in more complex systems. The leaves of most of the bromeliad species are arranged in way spiraled in a rosette, forming a cistern, or hit, which accumulates water of the rain, sediments of the dossel and other countless detritus. The decomposition of this debris contains many nutritious, which they are used not just by the bromeliad, through the located tricomas in their leaves, but also for other several organisms that participate in these intricate relationships. During this research 24 bromeliads of Vriesea friburgensis were collected, in elapsing of one year, and examined in search of macroscopic organisms, which were fastened in alcohol 70th and identified. These organisms were divided in seven classes, 20 orders and 50 families. The highlighted classes were Insecta and Arachnida. The most abundant orders were Coleoptera (45.3%), Hymenoptera (23.5%), Aranea (11.0%) and Diptera (9.7%); in keeping with result other similar works. Several ecological groups, or guilds, were established with base in the literature and field observations, looking for to increase the knowledge about the polytrophic relationships presented in this personal micro-universe. About 90% of total collected organisms belong to 15 families, and the three most found were Hydrophilidae (37.7%), Formicidae (23.5%) e Hahnidae (5.4%), witch ones were responsible for 67% of relative abundance on the community. The families with higher indices of relative frequency were Hydrophilidae (62.5%), Hahnidae (58.3%) e Formicidae (54.2%). The epiphytes bromeliads are different of the ground ones, some animals prefer one or another, the epiphytes have less biodiversity (H : 1,818) than the ground ones (H : 2,923). In the autumn were found the higher number of individuals (412), followed by winter (226), spring (226) and summer (190). The family richness were high on autumn (37), followed by winter (29), summer (27) and spring (18). This ecosystem can or could be a model and an example of polytrophic relationships, the systematic should use this diversity and help to identify the species witch depend of bromeliads to life.