Changes in Parasite Communities of Paralonchurus Brasiliensis (Sciaenidae) in Southeastern Brazil Across a Two-Decade Interval.

Birds are crucial in maintaining the balance of many ecosystems and provide various ecological services. Understanding their sensitivity to human disturbances should be prioritized in understudy areas for effective conservation practices. Using mist nets, this study characterized mostly understory bird communities (insectivorous, frugivorous, granivorous, and nectarivorous birds) in three habitat types (pristine forest, selectively logged forest, and young oil palm plantation) in the Talangaye rainforest, Southwest Cameroon. A total of 845 birds belonging to 27 families and 85 species were recorded in the three habitats after 294 h of mist netting. Overall, the mist-netted community was largely dominated by insectivores, followed by frugivores, nectarivores, granivores, and carnivores. Although mean species richness, abundance, and Simpson diversity index did not vary significantly among habitat types, mean species abundance and diversity index decreased in selectively logged forest and young oil palm plantation and species richness increased in both habitats. The species richness, abundance, and diversity index for insectivorous and frugivorous birds were lowest in the young oil palm plantations. For granivores, species richness and abundance increased following selective logging and the establishment of oil palm plantation. The highest mean species richness and diversity index in nectarivores were recorded in the young oil palm plantations. The study showed that selective logging and establishment of oil palm plantation had variable effects on the bird communities in the Talangaye rainforest. Also, the frugivorous birds appeared to be more sensitive to both types of disturbances, while the insectivores were more sensitive to habitat loss/conversion.

In July 2009 and July 2010 (two dry periods separated by an atypically large flood in the Pantanal wetland of Brazil), 34 and 33 specimens of the sardine fish Triportheus nematurus were collected, respectively, for the study of the metazoan parasite community of this species. Parasite ecological and community descriptors were calculated for both host samples, and possible similarities were tested statistically. Five species of metazoan parasites were identified, four of which were common to both host samples. A total of 61 metazoan parasites were collected from all fish hosts (17 specimens in July 2009 (mean: 0.5 ± 0.66 parasites/fish) and 44 specimens in July 2010 (mean: 1.33 ± 1.41 parasites/fish)). The nematode Procamallanus hilarii and the monogenean Anacanthorus sp. were the most prevalent and abundant species in 2009 and 2010, respectively. The mean total abundance and species richness were significantly higher in 2010. Parasite communities in both samples of T. nematurus were characterized by species with low prevalence, abundance, mean total abundance and species richness, thus indicating low parasite diversity. Significant differences in the prevalence and abundance of P. hilarii and Anacanthorus sp. between the two samples allowed the discrimination of infracommunities, which were united in two distinct groups. This appears to be the first evidence that the peculiar hydrological dynamics of the southern Pantanal wetland (Brazil) exert an important influence over the structure of the parasite community.

Management of forested landscapes for biological diversity is a major objective across North America. Perhaps the greatest potential to diversify future forests lies in the vast areas of young second-growth stands which may be managed silviculturally to accelerate ecosystem development. This study was designed to test the hypotheses that large-scale precommercial thinning, at ages 17–27 yr, to various stand densities would, over the 10-yr period since treatment, enhance: (1) productivity of lodgepole pine (Pinus contorta) crop trees, (2) stand structure attributes, and (3) species richness and diversity of forest floor small-mammal communities. Study areas were located near Penticton, Kamloops, and Prince George in south-central British Columbia, Canada, in three forest ecological zones. Each study area had three stands thinned to densities of ∼500 (low), ∼1000 (medium), and ∼2000 (high) stems/ha, with an unthinned juvenile pine and old-growth pine stand for comparison. Understory vegetation was measured in all stands in 1990, 1993, and 1998, and coniferous tree layers were measured in 1998. Small-mammal populations were sampled intensively in 1990, 1991, and 1998. Mean diameter increments of trees in the low-density stands were significantly higher than those in the medium- and high-density stands at all study areas. Mean height increments of trees were similar in the medium- and high-density stands and significantly higher than that in the low-density stands at Penticton and Prince George. Crown volume index (biomass) of herbs was highest in the thinned stands by 1998, but there was no difference among stands for shrubs and trees; volume of mosses was highest in the old-growth stands. Mean species richness and diversity of herbs, shrubs, and trees were similar among stands at 2, 5, and 10 yr after thinning. However, mean species diversity and structural diversity of coniferous trees were significantly higher in the low- and medium-density stands than in the high-density and unthinned stands 10 yr after thinning. Total structural diversity of all vegetation in the low-density stands was significantly greater than that of the medium-density, unthinned, and old-growth stands in 1998. Mean total abundance of all small mammals was similar among stands in 1990–1991, but the low-density and old-growth stands had the most mammals in 1998. Mean abundance of southern red-backed voles (Clethrionomys gapperi) was consistently higher (2.1–3.3 times) in the old-growth stands than in unthinned stands. In seven of nine cases, mean abundance of red-backed voles was similar among old-growth and thinned stands. Mean species richness and species diversity of small mammals were highest in the low-density and medium-density stands. Heavily thinned lodgepole pine stands developed structural attributes such as large diameter trees, large crowns, and structurally diverse vegetative understories. Forest floor small-mammal communities reflected the compositional and structural diversity of these managed stands.

Background: Snowy grouper Hyporthodus niphobles (Gilbert & Starks, 1897) (Perciformes: Serranidae) is a demersal marine fish species, distributed in the eastern Pacific and which does not report studies associated with its parasitic community. Goals: Evaluate the parasitic communities of the snowy grouper H. niphobles of the marine coast of Peru. Methods: Were acquired 126 specimens of H. niphobles from Pucusana, Lima, Peru. The data on total length (LT), weight (W), and sex (S) of the fish were recorded. For the analysis of the parasitic community, parasitological ecological indices, aggregation indices, alpha diversity indices and association between fish biometric parameters and parasitological indices were calculated. Results: The parasitic fauna in H. niphobles was composed of monogeneans, trematodes, cestodes, acanthocephalans and crustaceans distributed in eight species among endoparasites and ectoparasites. The monogenetic Microcotyle sp. was the parasite with the highest percentage of prevalence (65.87%), mean abundance (3.68), mean intensity of infection (5.59). The distribution type found was aggregated or contagious for species with prevalence greater than 10%. Only the mean intensity of Microcotyle sp. was found to be positively related to the weight of snowy grouper. A low heterogeneity was observed between the parasite community and the sex of the host (F=0.5, p=0.73). Main component analysis shows a low association between most variables with each of the two main components (KMO = 0.52; Bartlett’s test, X2 = 52.75, p=0.20). Conclusions: H. niphobles is considered a new host for eight parasites recorded in this study.

BackgroundFodder trees and shrubs are among the strategic feed resources that complement the dry season feed supply in the tropics. They are an integral element of the farming system incorporated into different land uses and deliver multiple functions, even though their diversity relies on various anthropogenic, physiographic, and agroecological factors.ObjectiveThe study aimed to identify indigenous legume fodder trees and shrubs (ILFTS) and estimate their diversity in terms of land use and agroecological zones in southern Ethiopia's Gamo landscape.MethodRespondent households were selected using a stratified multistage sampling procedure. Information about the ILFTS was gathered through key informant interviews conducted in each agro‐ecological zone. A total of 273 households from three agro‐ecological zones were selected and interviewed using a semi‐structured questionnaire to assess ILFTS. The information acquired by the questionnaire survey was complemented with a focus group discussion held with 10 respondents in each agro‐ecological zone. Herbarium samples were collected for each of the species for identification and confirmation of the botanical names. Sixty randomly selected sampling plots of each with a dimension of 20 m × 20 m were created, and inventories of ILFTS species were performed and recorded on species inventory sheets. The Shannon–Wiener diversity index (H) was used to determine the species diversity.ResultThe study identified 21 ILFTS that have been an integral constituent of the land uses recognised for their multiple functions in all agroecological zones. The mean species richness and diversity indices of the ILFTS differed significantly with land use and agroecological zones, where the lowland area closure exhibited the highest, and the highland homesteads and highland grazing land revealed the least.ConclusionFarmers’ indigenous knowledge and previous experience determined the species richness and diversity of ILFTS in farmlands and homesteads; however, the level of exploitation or protection was the reason for variation in area closure and grazing lands.

Responses of forest-floor small mammals to clearcutting are species-specific with generalists occupying a range of habitats, and specialists persisting on clearcuts for variable periods. We investigated the responses in abundance and species composition of small mammal communities to cumulative clearcutting of coniferous forests on a landscape that had four independent clearcutting events (Periods 1 to 4) over a 42-year interval from 1979 to 2020 in south-central British Columbia, Canada. We ask if the small mammal communities have changed significantly over these decades owing to removal of old-growth forest by clearcut harvesting. Hypotheses (H) predicted that the small mammal community would (H1) increase in abundance, species richness, and diversity on new clearcuts owing to the availability of early seral post-harvest habitats from cumulative clearcutting; and (H2) have higher mean abundance, species richness, and species diversity in clearcut than uncut forest sites, owing to availability of vegetative food and cover. A third hypothesis (H3) predicted that abundance of (i) early seral vegetation (herbs and shrubs) and (ii) small mammal populations, will be greater in ungrazed clearcut sites than in those grazed by cattle (Bos taurus). Mean total numbers of small mammals on new clearcuts declined in Periods 3 and 4, and hence did not support the abundance part of H1. Much of this decline was owing to low numbers of the long-tailed vole (Microtus longicaudus) and meadow vole (M. pennsylvanicus). Two generalist species: the deer mouse (Peromyscus maniculatus) and northwestern chipmunk (Neotamias amoenus), contributed to high mean species richness and diversity in Periods 2 and 3 before these metrics declined in Period 4, and hence partly supported H1. The similarity in mean total numbers of small mammals in Periods 2 to 4 did not support the abundance prediction of H2 that total numbers would be higher in clearcut than uncut forest sites. Higher mean species richness (Periods 2 and 3) and diversity (Period 3) measurements on clearcut than forest sites, particularly in the early post-harvest years, did support these parts of H2. The vegetation part (i) of H3 was not supported for herbaceous plants but it was for shrubs. The small mammal part (ii) of H3 that populations would be higher in ungrazed than grazed clearcut sites was supported for abundance but not for species richness or diversity. The decline and near disappearance of both species of Microtus was possibly related to the reduction in plant community abundance and structure from grazing (at least for shrubs) and potentially from drought effects associated with climate change. Loss of microtines from these early seral ecosystems may have profound negative effects on various ecological functions and predator communities.

Assessing man-induced environmental changes in the Sepetiba Bay (Southeastern Brazil) with geochemical and satellite data

Water discharge and sediment load to Sepetiba Bay from an anthropogenically-altered drainage basin, SE Brazil

Back on top: Resuspended by dredging and other environmental disturbances, organochlorine compounds may affect the health of a dolphin population in a tropical estuary, Sepetiba Bay

Differential metal and metalloid contents in fresh and cooked Charu mussels (Mytella charruana) from a southeastern Brazilian estuary and associated human health risks

Guiana dolphins (Sotalia guianensis) are commonly found in shallow waters from South and Central America. From March 2018 to June 2019, boat surveys were conducted to monitor two populations inhabiting the adjacent waters of Ilha Grande Bay and Sepetiba Bay to estimate population abundances and population parameters of apparent survival and capture probability. Photo‐identification was used as a mark‐recapture technique. A total of 672 dolphins was cataloged in Ilha Grande Bay and 826 in Sepetiba Bay, with two individuals being photographed in both areas. Population parameters were estimated through mark‐recapture models and total population abundance was estimated at 1,949 and 1,560 individuals in Ilha Grande Bay and Sepetiba Bay, respectively. Seasonal estimates were modeled showing that the Sepetiba Bay population may have stronger site fidelity to the study area than individuals in Ilha Grande Bay. Apparent survival was estimated in a mixed model framework avoiding bias due to the large presence of transient individuals. The estimates presented here are a result of an effort conducted months after an unusual mortality event linked to Guiana dolphin cetacean morbillivirus and our findings indicated that surviving individuals did not have long‐term deadly effects, but continuous efforts should be considered for a long‐term evaluation.

This work aims to identify the influence of climate change on sedimentary processes associated with the usual regression process during the rise of sea level in the early/middle Holocene in southeastern Brazil. The studied area is on the eastern side of Marambaia Barrier Island, which borders the eastern side of Sepetiba Bay (Rio de Janeiro State, SE Brazil). Nowadays, the Marambaia Barrier Island, a ≈ 40 km long and ≈ 5 km wide sandy ridge, shields Sepetiba Bay from the direct influence of the Atlantic Ocean. To achieve this goal, grain size, geochemical data (including elemental and stable isotopes), and radiocarbon dating data from sediment core SP10 (spanning depths from 8.2 to 45.5 m), collected in the eastern sector of the Marambaia Barrier Island were analyzed. Core SP10 predominantly consists of sandy sediments with some textural variations. However, Sr/Ba ratios suggest that brackish waters primarily influenced the depositional environment, which was also subject to cyclical marine incursions. The essentially felsic sediments of the interval between 45 and 41 m (≈ 10.0–8.5 ka BP) were probably deposited in a protected tidal plain estuary with mangroves. They were possibly mainly sourced from the nearby Pedra Branca Complex. Subsequently, between ≈ 41 and 11 m, the marine influence and hydrodynamics increased, and the sediments exhibited a more mafic mineralogical composition resulting probably from the erosion of the Rio Negro Complex, which is mainly found in the northern region of Sepetiba Bay. The mafic component likely reached the study area through coastal drift connected with Sepetiba Bay. During the drought period, recorded between ~ 7.5 and 7.0 ka cal BP (section 25–21 m), the contribution of the mafic component from the Rio Negro Complex decreased and less weathered sediments were accumulated. On the other hand, marine incursions into the study area became more prominent. During the drier climate phase recorded in the interval ≈ 11–9 m (after ≈ 4.0 ka BP), the La/Sc values indicate that the sediment included a higher proportion of felsic particles, probably due to more significant restrictions on the connection of the study area with Sepetiba Bay due to the development of the Marambaia Barrier Island. These findings are significant as they demonstrate the influence of geomorphology, climate change, sea level, and the development of Holocene barrier islands on the sedimentation in coastal regions.

The coordinated feeding tactics used by delphinids are influenced by differences in the distribution of prey species, season, and opportunities for social learning. In the present study, we compared the coordinated feeding behavior of two populations of the Guiana dolphin, Sotalia guianensis, in southeastern Brazil, and how these feeding tactics vary seasonality and in the presence of calves. We observed eight types of coordinated feeding tactics, which differed in frequency and in the mean number of individuals engaged in them, and between both areas. Feeding tactics used to herd and capture prey were the most frequent and engaged a greater number of individuals, suggesting that these tactics are better for capturing fish that gather in larger schools. Furthermore, the seasons influenced the occurrence of different prey items, which in turn modified the feeding tactics of the dolphins. In the Ilha Grande Bay we observed that bouts lasted longer and larger groups engaged in the feeding tactics, which may be associated with the seasonal spawning of larger schooling fish such as Sardinella brasiliensis (Steindachner, 1879) (Teleostei: Clupeidae). However, in the Sepetiba Bay, we observed longer feeding bouts and a smaller number of individuals engaged in the feeding tactics during autumn-winter. This may be associated with the fact that the most abundant prey species, Micropogonias furnieri (Desmarest, 1823) (Teleostei: Sciaenidae), gathers in small schools. Calves were present in 95% of all coordinated feeding tactics that occurred in the Ilha Grande Bay and in approximately 61% of feeding tactics in the Sepetiba Bay, suggesting that these areas are important for social learning. This study provides more information about feeding tactics and improves knowledge of the coordinated behavior of Sotalia guianensis (Van Beneden, 1864).

Sepetiba Bay, located in southwestern Rio de Janeiro state, in southeastern Brazil, is a region of extreme anthropogenic impact, and is home to a large population of Guiana dolphins, which face increasing and cumulative pressures on their physical health. Cetacean body condition provides a useful indicator for the evaluation of the conservation status of marine mammals. Given this, the present study quantified the proportion of dolphins with different body condition scores and assessed temporal variation in these scores between 2017 and 2022 through the analysis of photographic records. We analyzed the photographs and identified the individuals using FinFindR and classified each individual based on its apparent body condition. A total of 29,737 photographs were taken during the study, and 79 individuals were identified, of which 68.35% were in poor condition. The evidence suggests that the Guiana dolphins are in relatively poor condition overall, possibly reflecting the cumulative impact of human activities in Sepetiba Bay.

We sampled fish and measured environmental variables in the Sepetiba Bay, a tropical embayment at Southeastern Brazil. The aim was to assess environmental influences on distribution of four abundant species of Sciaenidae Micropogonias furnieri (Desmarest, 1823), Ctenosciaena gracilicirrhus (Metzelaar, 1919), Cynoscion leiarchus (Cuvier, 1830) and Menticirrhus americanus (Linnaeus, 1758) to test the habitat partition hypothesis. Samples were taken between June 1993 and July 1996, at three bay zones (outer, central and inner). Depth was the most important environmental variable to influence fish distribution, followed by transparency. M. furnieri showed significant negative correlation to depth, transparency and salinity, while C. gracilicirrhus showed the opposite situation. The highest densities of C. leiarchus occurred in the lowest temperature, while M. americanus did not showed preferences for any of the examined environmental variables. Spatial separation, mainly between M. furnieri and C. gracilicirrhus, seems to be the strategy developed to coexist in the Sepetiba Bay, with M. furnieri being more adapted to copy with harsh environmental conditions of the inner bay. The other three species, which use mostly the outer bay zone, seem to be restricted to more stable conditions, where influences from oceanic waters are more intense.