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.

In aquatic ecosystems, allochthonous inputs of leaf litter are common substrates for the invertebrates communities. The quality and physical structure of these substrates are expected to strongly determine benthic invertebrates structure and functioning. Therefore, we carried out an experiment to evaluate the association between these organisms and the chemical traits of leaf litter from 16 restinga plant species in Jurubatiba lagoon, a coastal aquatic ecosystem at Restinga de Jurubatiba National Park. After 123 days, litter mass loss varied from 14 - 30%, indicating that decomposition was in the initial stage for most species. Litter converged to have a similar nutritional quality after this time submerged. Initial K concentration positively affected, whereas initial lignin and C concentration negatively affected species richness and diversity. It indicates that nutrients attract whereas structural compounds limit benthic species colonization. Chemical compounds such as C, nutrients (N, P, K and Na), lignin and cellulose tended to be positively associated with the dominant taxa (Chironominae n.i. and Heleobia australis) and functional feeding groups (scrapers and collector-gatherers). However, no significant associations were detected by the redundancy analyses. We may conclude that litter quality affect benthic structure, but not community composition nor FFG distribution at Jurubatiba lagoon. The benthic composition and FFG may be randomly distributed among litter substrates or may be better explained by some other litter aspect(s) different from those considered in this study. Future studies may also consider the temporal dynamic of litter colonization to better elucidate the relationship between litter traits and invertebrate community.

No abstract

No abstract