Abstract
Abstract: The aim of this study was to analyze aquatic oligochaete distribution in relation to water column physicochemical variables, structural environmental variation, and predominant substrates in the preserved Amazonian streams of the Saracá-Taquera National Forest (FLONA Saracá-Taquera), northwest Pará, Brazil. Oligochaetes are widely used as bioindicators for monitoring aquatic environments as they are very sensitive to pollution and environmental changes. Physicochemical and structural variables were measured from 100 stream segments in order to understand the distribution of oligochaetes in Amazonian streams. Biotic samples were collected using Surber samplers in three of the most predominant substrate types in each segment. PERMANOVA testing showed that there was a significant difference in the oligochaete community among some substrates, potentially caused by a difference in the abundance of the most common taxa. Canonical Correspondence Analysis showed that physical variables drive the distribution of oligochaetes in preserved Amazonian streams, as they determine the formation of different substrates along the stream, from the source to the mouth; favoring the presence of oligochaetes with more specific ecological needs in low-order streams, and the presence of oligochaetes capable of colonizing various types of substrates and deeper zones in high-order streams. These results suggest that water depth and channel width are the main drivers of aquatic oligochaete distribution along Amazonian streams, determining the formation of unstable and low-quality substrates and, consequently, the low colonization by oligochaetes in high-order streams; and more diverse and stable substrate formation in low-order streams, favoring the colonization by diverse taxa of aquatic oligochaetes in low-order Amazonian streams.
Highlights
Oligochaetes play important roles in aquatic systems, such as in food webs, as a source of food for other invertebrates, fish, and birds (Ezcurra de Drago et al, 2007); in the organic matter decomposition process; and fulfilling an important role in the cycling of nutrients, participating in sediment structuring and nutrient exchange in the water/ sediment phase (Golterman et al, 1983).They are good indicators of environmental conditions (Verdonschot, 2001) because they have limited mobility, long life cycles, an intimate relationship with substrates and they are extremely influenced by the habitat characteristics in which they live (Behrend et al, 2009)
This study showed that substrate types, water depth, and channel width are the main drivers of aquatic oligochaetes distribution in Amazonian streams
These variables determine the formation of unstable substrates in high order streams; substrates that cannot be used as refugia and lacking in food sources, which may limit the colonization and establishment of some Oligochaeta species
Summary
Oligochaetes play important roles in aquatic systems, such as in food webs, as a source of food for other invertebrates, fish, and birds (Ezcurra de Drago et al, 2007); in the organic matter decomposition process; and fulfilling an important role in the cycling of nutrients, participating in sediment structuring and nutrient exchange in the water/ sediment phase (Golterman et al, 1983) They are good indicators of environmental conditions (Verdonschot, 2001) because they have limited mobility, long life cycles, an intimate relationship with substrates and they are extremely influenced by the habitat characteristics in which they live (Behrend et al, 2009). It is important to know how oligochaetes are distributed and which of this community’s structuring variables are present in tropical systems like those found in the Amazon, whereby mineral exploitation is an expanding activity that can impact these environments (Castello and Macedo, 2016)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
