Tesis
Diversidade e distribuição espacial de Ephemeroptera (Insecta) em riachos do Planalto Sul-rio-grandense, Brasil
Fecha
2015-04-27Registro en:
BERTASO, Tiago Roberto Nunes. Diversity and spatial distribution of Ephemeroptera (Insecta) in streams of Planalto Sul-rio-grandense, Brazil. 2015. 45 f. Dissertação (Mestrado em Ciencias Biológicas) - Universidade Federal de Santa Maria, Santa Maria, 2015.
Autor
Bertaso, Tiago Roberto Nunes
Institución
Resumen
The additive partition diversity has been a promising method to analyze patterns of
diversity in hierarchical studies. Streams are recognized for having a spatial structure
hierarchically organized in increasing scales, ranging from places such as habitat,
stretch, streams and the entire drainage system. The diversity and spatial distribution of
mayfly nymphs communities were studied over four hierarchical spatial scales in
Planalto Sul-rio-grandense (sampling units, substrates, streams and basin). Additionally,
the influence of local environmental descriptors on the structure of the nymphs
communities was tested. Samples were collected in 13 streams of two independent parts
of the Planalto Sul-rio-grandense, in each stream were obtained 10 samples in falls five
in stone substrate and five in leaves. The spatial distribution of mayfly nymphs showed
structuring according to types of substrates sampled. The partitioning of diversity
among the analyzed scales revealed that the major portion of beta diversity occurred
between the sampling units and between the streams of the same dimension and a very
small amount in the range of substrate. Thus, we assume that the fauna of aggregation in
the smaller spatial scale was not due to substrate differences associated with rapid but
the variation between rapids, reflecting the predominance of specific processes related
to the availability of resources. We assume also that the nymphs of ephemeral not have
barriers to the use at these substrate, which could actively move between the rapids of
streams. In addition, the diversity that occurs between streams of the same part, can be
attributed to local characteristics of each stream, such as slope, conductivity and current
velocity. Finally, three environmental descriptors (altitude, slope, and dissolved oxygen)
were important to structure the mayfly community at the streams of Planalto Sulriograndense.
We conclude that the scales from rapids (sampling units) and between
streams are scales that have the largest portion of the variability of the taxonomic
composition showing to be more effective in assessing the spatial variation of mayfly
nymphs communities.