This study aimed to characterize and evaluate factors driving the structure of the benthic macroinvertebrate community in coastal lagoons at the Restinga de Jurubatiba National Park. Sixteen lagoons were sampled in July 2010 during the dry season. At each lagoon, three samples were taken in the central region and three samples were taken near the sandbar. At each point, the limnological variables and the benthic community were collected. Richness and abundance were calculated for each sample. The correlations among the environmental parameters were tested using Pearson's correlation. A Principal Component Analysis using environmental variables was performed to visualize the similarity among samples. Simple regressions were used to assess the correlation between macroinvertebrates' metrics and environmental parameters. A redundancy test was performed to link environmental parameters to the community structure of macroinvertebrates. A total of 1,719 macroinvertebrates were identified in 25 taxa groups that were classified as exclusive marine taxa, five as brackish/marine taxa, seven as freshwater taxa, and two taxa as groups with marine and freshwater representatives. The most abundant taxa were Leonereis sp., Heleobia australis, and Kalliapseudidae. Richness and abundance were negatively related to salinity. The redundancy test indicated pH, salinity, coarse grain size, and dissolved oxygen as the environmental variables explaining the macroinvertebrate community structure variation among the lagoons. Understanding the drives and dynamics which guide the macroinvertebrates communities' turnover in coastal lagoons is a relevant tool to subsidize environmental management decisions due to the increasing threats around the park.

Riverscape aggradation due to the deposition of fine particles above natural forest litter can change the soil, sediment, and water properties, damage riparian vegetation, and reduce environmental integrity, especially in headwater streams. Litter addition techniques that enhance surface roughness and permeability can decrease the interference of fine particles on the ecosystem, representing a low-tech alternative to recover disturbed riparian areas. We aimed to evaluate run-off, percolation, storage coefficients, run-off volume, and sediment yield using a rainfall simulator and the mitigation potential provided by the addition of forest litter to limnological variables-turbidity, total suspended solids (TSS), electrical conductivity, pH, nitrogen-which are indicators of integrity that can reflect streams' aggradation. Fifteen soil samples from a disturbed area (silt and clay deposits aboveground), five from an undisturbed area (sandy soil), and superficial forest litter were obtained from riparian areas adjacent to two small streams in Caraj as National Forest, Brazil. The addition of litter showed great potential to mitigate erosive processes and to reestablish hydrological processes in the disturbed soil. The run-off volume and sediment yield were 2-4 times lower in litter addition treatments compared to non-litter addition. Litter addition also improved run-off water quality, especially turbidity and TSS, which were 12-16 times and 3-13 times lower, respectively. The experimental addition of litter has shown encouraging results to be applied in situ as a sustainable, low-cost, and simplified nature-based solution to contribute to the restoration of degraded riparian forests and reduce in-stream silt and clay aggradation.

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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.