Dissertação
Diversidade e conservação de Aegla leach, 1820 (Crustacea, anomura) em área prioritária para preservação
Fecha
2022-09-16Autor
Mollmann, Victor Hugo dos Santos
Institución
Resumen
Freshwater crustaceans of the genus Aegla Leach, 1820 are important components of the fauna of rivers,
streams, lakes, and caves of several countries in South America, where they are endemic. Currently, the genus
is represented by 93 described species, but it is estimated that this number could be much higher, given the
cryptic complexes discovered in Aegla paulensis, Aegla longirostri, and Aegla uruguayana. Cryptic species
complexes are a taxonomic problem present in several taxa, especially those with morphological
conservation, underestimating the real diversity of species, bringing implications in conservation and
management of the biodiversity. In Brazil, the southern region concentrates most of the species’ diversity of
Aegla, and previous studies have shown that the ecoregions of Upper Uruguay, Tramandaí-Mampituba, and
Laguna dos Patos Basin compose a large priority area for eglid conservation, due to the high number of
species and phylogenetic diversity, high endemism, and threats to the aquatic habitat. And precisely this
threat to the aquatic environment serves as the background for Chapter I, in which we evaluate the
preservation of freshwater environments within these priority areas, where four large Protected Areas (PA)
are located. Water quality was assessed in 33 sampling sites distributed inside and outside the PAs, through
physicochemical and microbiological analysis and detection of pesticides and pharmaceutical compounds, to
observe factors that threaten aquatic biodiversity. Water quality did not differ significantly between protected
and unprotected sites, but indicated clear pollution, with evidence of sewage inflow, even in well-conserved
areas. We found 19 pesticides and five pharmaceuticals in water samples from the analyzed region. All the
sampled sites presented at least one pesticide and one pharmaceutical compound, especially 2,4-D, present
in 91% of them. The different data sources allowed us to observe that PAs are not enough to mitigate anthropic
pressures, and preservation and management measures must take into account the entire watershed since
rivers and streams go beyond the limits of PAs. The results provide a context for evaluating the influence of
anthropogenic impacts on aquatic biodiversity, especially species of the genus Aegla, since the degradation
of aquatic environments is one of the main factors responsible for a large number of species of the genus that
are threatened with extinction, and preventive measures for the conservation of the aquatic environment
become essential to protect biodiversity. In Chapter II, we accessed the diversity and distribution of Aegla in
the priority region specified above, also testing the hypothesis of the existence of cryptic complexes among
species in the region. For this purpose, we used species delimitation methods applied to mitochondrial COI
gene sequences, together with phylogenetic and morphological analyses. We observed 22 potential new
species, divided into three cryptic complex clusters: seven putative species in Aegla jarai, three in Aegla
franciscana, and one in Aegla camargoi, plus an impressive 11 other putative species not included in any
cluster, evidencing that the real diversity of the group is still largely unknown. Our results indicate that the
study region has the highest species richness of Aegla, which makes it an even higher priority for the
conservation of the genus and preservation of its habitat. Also, integrative taxonomy is the best way to detect
new species in groups with conserved morphology.