Grupos substitutos, correspondência de assembléias aquáticas em relação a esquemas de classificação regional, e determinantes de diversidade beta em uma planície de inundação neotropical
Carregando...
Data
2010-01-25
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
A general goal in community ecology is to understand how communities are
organized in space and time. An aspect of great interest is to evaluate how concordant
are the patterns of beta diversity depicted by different biological groups. If two
taxonomic groups present a similar spatial/temporal structure, only one of these groups
can be used as a surrogate group in conservation efforts or bioassessments. Also, a
strong correspondence between biological groups and physical classifications of the
habitat could help us to understand the reasons for spatial organization of communities.
Moreover, if communities respond to a priori classifications based on geological and
environmental features of the habitats, the selection of priority areas for conservation
distributed on the classes of a classification scheme could maximize the conservation of
overall biodiversity. Finally, to understand the main processes driving the organization
of communities, the relative role of different set of predictor variables can be
simultaneously evaluated. If species compositions are mainly predicted by
environmental variables then one can conclude that species sorting mechanisms are the
main drivers of community structure. On the other hand, if variables that represent
spatial structure of the environments are the main predictors of variation in species
composition, then neutral processes may be invoked to explain the structure of the
biological group under analysis. Therefore, the main goals of this thesis are: (i) to
evaluate the concordance among distinct biological groups; (ii) to evaluate the
correspondence between a priori physical classifications of the habitat and the
composition of assemblages and; (iii) to evaluate the relative role of environmental and
spatial predictors on the structure of local assemblages in a Neotropical floodplain. For
that, we used data sets on six biological groups (fish, benthic macroinvertebrates,
aquatic macrophytes, zooplankton, phytoplankton, and periphyton) which were gathered
during 2000 and 2001 in up to 36 aquatic environments of the Upper Paraná River
floodplain. Patterns of assemblage concordance were frequently observed. The main
mechanisms responsible for cross-taxon concordance were a similar response to
environmental/spatial gradients and biological interactions between species. The
mechanisms were identified after controlling for the effect of environmental/spatial
variables on the cross-taxon concordance and after evaluating the level of concordance
between species from each group that most likely are linked by biological interactions.
However, the levels of assemblage concordance were weak and varied conspicuously
with time. These results highlight that the use of surrogate groups is a flawed strategy to support conservation efforts in the Upper Paraná River floodplain. Nevertheless, the
classification scheme of the floodplain, considering mainly limnological and geological
aspects, was efficient to represent the structure of different aquatic assemblages. Thus,
conservation efforts and bioassessments of the aquatic flora and fauna can use this
classification scheme. However, the temporal variability also affected the consistency of
the correspondence and this issue should be further investigated. On the other hand,
temporal variables were not effective in predicting the structure of different biological
assemblages. Environmental and spatial variables were generally more important, but
also with low predictive power. Spatial variables were particularly important for large
organisms with low dispersal ability, such as sedentary fish and aquatic plants. On the
other hand, compared to spatial predictors, environmental variables were more
important to explain the structure of small-bodied organisms with high dispersal ability
(such as micro-algae) and organisms with migratory behavior. Nevertheless, all
variables had a low predictive power, probably due to the low extent of the
environmental and spatial gradients and to the lack of variables that represent relevant
processes for determining the structure of aquatic assemblages in floodplains.
Descrição
Citação
PADIAL, André Andrian. Groups substitutes, matching assemblies
waterfowl in relation to regional classification schemes, and
determinants of beta diversity in a floodplain
neotropical flood. 2010. 129 f. Tese (Doutorado em Ciencias Biologicas) - Universidade Federal de Goiás, Goiânia, 2010.