Rich Fauna Research Articles

Paleogeographic implication of a titanosaur eggshell from the Neogene of the Entre Ríos Province, Argentina

The Lower Member of the Ituzaingó Formation (LMIF), fluvial in origin and assigned to the Upper Miocene, contains a conglomerate level known as “Mesopotamiense” or “Conglomerado osífero” that has yielded a rich fauna of vertebrates. The aim of this contribution is to describe a titanosaurian dinosaur eggshell fragment recovered from the LMIF at the locality of Toma Vieja (western Entre Ríos Province), discussing its paleogeographic history and implications. Fragments of eggshells referred to Titanosauria are frequent from litostratigraphic units of the Upper Cretaceous of western Uruguay (e.g., Guichón, Mercedes, and Queguay Formations). Besides, a fragment of eggshell recovered from the Puerto Yeruá Formation (Upper Cretaceous) at eastern Entre Ríos Province was described. Geophysical data from the Entre Ríos Province allow to propose the presence of a Lower Cretaceous field of extensional tectonic stresses that generated structural lineaments with a E-W and ENE-WSW trend. This ancient penetrative Cretaceous tectonic framework would have exerted control on the shape of the basin and sediment flow patterns and subsequent sedimentation, by promoting the generation of accommodation space over the late Paleogene and the Neogene. The phenomenon would have conditioned the deposition of the Fray Bentos Formation, the subsequent marine Paraná Formation, and the sedimentation of the LMIF, with source materials coming from the east. Thus, it is hypothesized that the fragment of eggshell of Titanosauria would come from the eastern area of the basin (western Uruguay) as a consequence of the existence of a paleohydric system with predominantly E-W and ENE-WSW directions. This late Neogene system would have been controlled by inherited Cretaceous structural lineaments with orientations similar to those that also govern the current fluvial systems of western Uruguay, developed on the Mesozoic substrate.

Sedimentology and structure of the Paleogene Nummulitic series of Corsica: Reconstruction of the southern termination of the western Alpine foreland basin

AbstractNummulitic Limestones deposits are preserved along the tectonic contact between the Variscan basement and Alpine units of Corsica. These marine carbonates, dated from the Late Palaeocene to the Middle Eocene, were deposited within a foreland flexural basin that is considered to be the southern continuation of the Alpine foreland basin of southeast (SE) France. However, in contrast with the Nummulitic Limestones of SE France, those of Corsica are far less documented. This field‐based study constrains the sedimentology, stratigraphy and structure of the Nummulitic Limestones of Corsica in three localities (Balagne, Corte and Sari‐Solenzara) to identify factors that controlled foreland basin development and to clarify its significance within the early alpine orogen. The microfacies, microfaunal assemblages and siliciclastic fractions are characterised throughout the succession at each locality. The results indicate the existence of an important Variscan basement relief to the west of the basin (West Corsican Massif) that supplied early alluvial fans found at the base of the foreland succession in the northernmost Balagne area. Continuous high clastic input strongly reduced the development and diversity of the overlying Nummulitic Limestones facies and fauna. Further south, limestones in the Corte and Sari‐Solenzara areas are thicker and contain richer fauna. Three depositional models corresponding to the carbonate ramp system are proposed for the Nummulitic Limestones and used to construct paleogeographic maps illustrating the transgressive evolution of the Corsican foreland basin from the Early to the Late Eocene. Based on our results and available regional tectonic data and LT thermochronological data, we propose that the Nummulitic marine transgression took place within a continuous foreland basin encompassing southern Corsica and SE France during the early development of the western alpine arc.

‘The Elephant in the Room’ – does actual or perceived biodiversity elicit restorative responses in a virtual park?

ABSTRACT Previous studies suggested that urban green spaces with rich fauna and flora (i.e. rich biodiversity) improved well-being, in the form of reduced stress and better mood. However, few studies manipulated the biodiversity experimentally and controlled for potential confounders. In the current study, an online experiment tested the hypothesis that more biodiverse green spaces will elicit greater well-being. Over 1600 participants from the UK and China reported their mood before and after virtually exploring the same urban park but with lower or higher macro-biodiversity (plants, birds and mammals). All participants also rated their perceived biodiversity (i.e. how many kinds of plants and animals they guessed to be present). The results showed that all park variations produced improved mood, especially in stressed participants. This counters the initial expectations that maximum biodiversity correlates with higher well-being. Instead, participants who perceived higher biodiversity reported greater mood improvements than those who perceived low biodiversity. However, the perceived biodiversity overestimated the actual biodiversity. Interestingly, these findings were consistent in both UK and China samples. This indicates that well-being benefits and stress recovery can occur in parks with low and high biodiversity. However, greater well-being effects can be gained if park visitors perceive and notice more biodiversity.

DYING FROGS IN WESTERN COLOMBIA: CATASTROPHE OR TRIVIAL OBSERVATION?

The encounter of dead or dying frogs of seven cloud forest species in July 1997 during an unusually dry period in the Serranía de los Paraguas could be an indication of a collapse of a rich fauna. Subsequent study suggests that the populations are healthy and that the observations are trivial.

Snails of ‘sky islands’ above an equatorial desert: Terrestrial molluscs on four isolated mountain ranges in northern Kenya

AbstractThe mountains of northern Kenya (Ndoto, Nyiro, Kulal and Marsabit) are separated by semi‐arid plains uninhabitable for most terrestrial molluscs (snails and slugs). Nevertheless, each “sky island” supports a little‐known forest mollusc fauna. The diversity and endemism of these faunas are addressed here based on surveys and the limited records available in the literature. In total 75 forest mollusc species and subspecies were found, including six previously undescribed Streptaxidae and many first records. Most previously recorded taxa were refound. The richness of faunas is broadly comparable to that of other Kenyan forests surveyed using similar methods (Ndoto 41 taxa, Nyiro 40, Kulal 33, Marsabit 34). A large proportion of the forest taxa (24 taxa, 29%) are endemic to Kenya north of the Mathews Range. More than half of these (14 taxa, 17% of the total) are known only from a single mountain range. At Nyiro, where different forest types were compared, fewer endemic species were found in Juniper forest than in other forest types. Moving northwards along the Ndoto‐Nyiro‐Kulal chain, diversity declines while endemism increases, perhaps reflecting increasing isolation from the southern forests, but the trends are not significant when Marsabit is included. Across the four ranges, neither diversity nor endemism is clearly linked to the isolation, maximum elevation, forest cover or geological origin of each range (Kulal and Marsabit are volcanoes, while Nyiro and Ndoto are uplifted basement rock). Instead, the unique circumstances of each range create a distinctive set of isolated faunas.

Richness, Complementarity, and Community Structure of Amazonian Mammal Faunas: Results from Multiyear Inventories in French Guiana and Peru

Richness, Complementarity, and Community Structure of Amazonian Mammal Faunas: Results from Multiyear Inventories in French Guiana and Peru

Species Richness and Diversity of Insects in an Argo-ecosystem in Bhabar Region of Uttarakhand

The aim of the presented study was to estimate the species richness and diversity of insects were investigated in an agro-ecosystem in Bhabar region of Uttarakhand. In total, 992 individuals were collected representing 7 orders (Lepidoptera, Coleoptera, Hemiptera, Hymenoptera, Orthoptera, Diptera and Odonata), 30 families and 91 species that included herbivores, predators, omnivores and saprophages. The most dominant order was Lepidoptera with a relative abundance of (46.15%) and, the least was Diptera (6.59%). The five most abundant families by numbers of individuals were Pieridae (14.8%), Nymphalidae (13.9%), Lycaenidae (6.1%), Papilionidae (5.9%), and Libellulidae (5.4%). The five most diverse families by species were Nymphalidae (13), Pieridae (9), Lycaenidae (8), Papilionidae (7), and Libellulidae (6). The diversity index showed significant Diversity (Hʹ=1.832), Evenness (E=0.9449) and Margalef species richness (d=2.076) of insect fauna. Diversity indices of insect orders showed that Lepidoptera was the most diverse (Hʹ=1.641), Dipterans had highest Evenness (E=0.9449), and Coleopterans had the maximum species richness as per Margalef’s Index (d=2.056). There were 720 individuals of insect pollinators visitors were observed, which belonged to 62 species in 4 orders (Lepidoptera, Coleoptera, Hymenoptera, and Hemiptera).

Artificial rockpools create habitat refugia on seawalls at high tide

Rockpools are fundamental habitats on natural rocky shores that provide refugia for marine life at low and high tide. Yet, artificial coastal structures lack the topographical complexity seen in these natural habitats. Eco-engineering, that may include the deployment of artificial rockpools, attempts to address the lack of suitable habitat on coastal infrastructure but most studies focus on species abundance metrics at low tide. It is important to understand how eco-engineering interventions may provide habitat at high tide compared to the surrounding artificial substrate.In this study, we demonstrate how groups of rockpools (1, 3 or 5 rockpools) add habitat complexity at high tide to a concrete seawall in Poole Harbour, UK. Between April and October 2022, eighteen GoPro cameras were deployed to record species richness and abundance in artificial rockpools and the adjacent concrete sea wall. Additionally, the length of time the most abundant fauna (the shanny fish Lipophrys pholis and the European shore crab Carcinus maenas) spent engaging in different behaviour (resting, feeding, moving) was recorded.Overall, there was no significant difference in the abundance and species richness of mobile fauna using the artificial rockpools versus the seawall. However, both the shanny and shore crab generally spent more time in the rockpools than on the seawall. Both crabs and shanny preferentially engaged in feeding behaviours on the seawall, which has been attributed to the high percentage cover of barnacle prey. Crabs and shanny spent more time resting in the rockpools than the seawall and the only reproductive behaviour observed occurred within the rockpools. Our work suggests that artificial rockpools support the habitat needs and multiple life history requirements of these species at high tide. Both the seawall and rockpools provide valuable resources, which further emphasises the need for variety in eco-engineering feature designs.

Clinical outcomes in a murine model after envenoming by the Amazonian scorpions Tityus strandi and Tityus dinizi

The Brazilian Amazon is home to a rich fauna of scorpion species of medical importance, some of them still poorly characterized regarding their biological actions and range of clinical symptoms after envenoming. The Amazonian scorpion species Tityus strandi and Tityus dinizi constitute some of the scorpions in this group, with few studies in the literature regarding their systemic repercussions. In the present study, we characterized the clinical, inflammatory, and histopathological manifestations of T. strandi and T. dinizi envenoming in a murine model using Balb/c mice. The results show a robust clinical response based on clinical score, hyperglycemia, leukocytosis, increased cytokines, and histopathological changes in the kidneys and lungs. Tityus strandi envenomed mice presented more prominent clinical manifestations when compared to Tityus dinizi, pointing to the relevance of this species in the medical scenario, with both species inducing hyperglycemia, leukocytosis, increased cytokine production in the peritoneal lavage, increased inflammatory infiltrate in the lungs, and acute tubular necrosis after T. strandi envenoming. The results presented in this research can help to understand the systemic manifestations of scorpion accidents in humans caused by the target species of the study and point out therapeutic strategies in cases of scorpionism in remote regions of the Amazon.

AGROBIODIVERSITY AND ASSOCIATED TROPHIC INTERACTIONS AS AN INDICATOR OF SUSTAINABILITY IN PRODUCTIVE SYSTEMS

Biodiversity is crucial in agroecosystems, as it makes them more efficient, stronger, productive and resilient. The aim was to determine and compare the existing biodiversity in two different production systems: agroecological and industrial during 2018 and 2019 in the INTA Barrow (Buenos Aires, Argentina). Sampling of mammals, birds, arthropods and spontaneous vegetation were made in wheat and oat crops. Several parameters were estimated including abundance, density, richness, dominance, diversity and equitivity for each study group. The agroecological system presented higher density of birds and mammals, richness of arthropods and spontaneous species compared to the industrial system. The greater agricultural diversification in the agroecological system evidenced a more complex landscape structure, through the increase in the richness of spontaneous species and beneficial fauna that would increase the potential for biotic regulation of the system.

Diversified cropping strengthens herbivore regulation by providing seasonal resource continuity to predators

Abstract Agricultural practices shape arthropod communities in arable fields, consequently influencing their interactions and the resulting ecosystem services, in particular pest regulation. Predatory arthropods play a pivotal role by preying on herbivores, soil fauna, and on other predators. However, the intricate mechanisms through which agricultural practices shape the dietary preferences of predators, and regulate herbivore populations remain complex and inadequately understood. We assessed how fertilisation with organic fertiliser and extending crop rotations with perennial ley affected predation pressure across prey taxa. We mapped predator and prey trophic linkages with molecular analysis of carabid predator gut contents, and measured densities and taxonomic richness of predators, herbivores, and soil fauna in 19 cereal fields during three samplings across the growing season. We derived two food web structure metrics: prey vulnerability that is the average number of predators feeding on a selected prey, and predator trophic redundancy, that is dietary overlap. Prey vulnerability was compared among soil fauna, herbivores, and other predator species (that is interspecific intraguild predation) over the growing season, and across treatments. The mechanistic underpinnings of observed shifts in vulnerability of herbivorous prey at different crop stages were identified using information criteria to select among candidate variables related to the richness, density and interaction structure of the different guilds during both the current, and the previous crop stages. Agricultural diversification via organic fertilisation combined with perennial ley in the crop rotation decreased the vulnerability of both intraguild prey and soil fauna prey, and stabilised herbivore vulnerability. Mechanistically, the vulnerability of herbivorous prey at crop ripening emerges from the combination of predator richness and trophic redundancy during this sampling round, rather than from carryover effects from previous crop stages. Synthesis and applications: Our results suggest that locally provided resource continuity through diversified cropping practices bolster biological pest regulation, thus underline the importance of lesser disturbance in arable ecosystems for the provision of ecosystem services. Enhanced predator species richness together with availability of alternative prey through the season underpins this enhanced pest regulation.

To the Ecology of Bumblebees (Hymenoptera, Apidae, Bombus) in Talysh

The Talysh zone (Lenkoran natural area), due to different types of landscapes and climate, has a rich fauna and flora, many of which are endemic. There are 28 species of bumblebees living here, belonging to 7 zoogeographical complexes, which makes up 55% of the bumblebee fauna of Azerbaijan. In the lowlands and in foothill landscapes up to an altitude of 1000 m, where a humid subtropical climate prevails, only 4 species of bumblebees were found. In the zone of dry steppes and settled meadows, at approximately an altitude of 1400 to 2400 m, where a dry continental climate prevails, bumblebees are represented by 18 species. Bumblebees, with their perfect social life, are active throughout the season. As a result of studying the phenology of bumblebees’ flight, it was revealed that in the study area they begin flying from the beginning of April (4 species). During the summer months the number of species reaches its maximum (an average of 25 species). From the beginning of autumn, the growing season of flowering plants ends, and the number of bees decreases, but the number of bumblebee species is comparatively greater.

A review of long-legged flies from the Republic of Guinea (Diptera:Dolichopodidae) with description of a new Lichtwardtia species

A new long-legged fly species, Lichtwardtia guineensis Grichanov sp. nov., from the Nzérékoré Province of Guinea, is described and illustrated. Males of the new species are similar to L. angulicornis Grichanov, from Ivory Coast, but differ in face colour, postpedicel shape, and features of the male genitalia. In addition, 13 species are listed for the Republic of Guinea, of which, eight are reported from the country for the first time: Apelastoneurus nigeriensis (Grichanov), Lichtwardtia angularis (Macquart), L. angulicornis Grichanov, L. fractinervis (Parent), L. microlepis (Parent), Pseudopelastoneurus diversifemur (Parent), Sympycnus du Curran and Sympycnus minor Parent. As a result, the dolichopodid species number in Guinea has increased to 14. It is supposed that the real number of Guinean species may reach 50 to 100 species, based on the faunal richness of adjacent countries.

Diversity pattern of insects from Macao based on an updated species checklist after 25 years.

Insects represent one of the most diverse groups in the organism world with extremely rich species and morphological diversity, playing important roles in natural and city ecosystems. Regional compilation of insect species lists helps to clarify the richness of insect species in a region, enhances our understanding the structure and function of a local ecosystem and promotes the protection and development of insect resources. Moreover, it also serves as a valuable reference for cities with small area, large population and high urbanisation like Macao. Macao (Macau) Special Administrative Region (SAR) is situated at the Pearl River Delta on the southeast coast of mainland China. With urban development accelerating at great rate in a quite restricted area, Macao still has rich fauna, within which the insect diversity is surprisingly high. In this study, we systematically sorted out major references items of manuals or handbooks, monographs, articles, dissertations, official websites and other publicly available information sources about the insects recorded in Macao and, thus, generated a checklist of 15 orders, 166 families, 868 genera, 1,339 species and 118 subspecies. During this process, the preliminarily summarised list was re-examined to eliminate synonyms and invalid species, based on many more extensive literature reviews. Besides, spelling errors of scientific names, authors and years were corrected. Meanwhile, the catalogue revealed a different composition pattern of species diversity between orders from those of the world and China. Even based on the most conservative estimates, the number of insect species in Macao should not be lower than 3,340 species, which hints at the necessity of deeper investigations with adequate collecting in the future to achieve more comprehensive recognition and understanding of Macao's insect biodiversity.

Problems of the interrelationships of crown and stem amniotes

Amniota is a tetrapod group that was recognized originally in the 19th century on the basis of developmental features (extra-embryonic membranes), but since the widespread adoption of phylogenetic systematics in the late 20th century, it has been recast as a crown clade. The oldest amniotes are Late Carboniferous in age (ca. 318 million years ago), and they are preserved in coal beds and lycopod tree stumps that have yielded rich faunas of temnospondyls, anthracosaurs, and other early tetrapods. Numerous phylogenetic studies of the past three decades have focused on the relationships of amniotes to other early tetrapods, resulting in the prevailing picture that Amniota is the crown of a total group with many extinct Paleozoic clades comprising its stem group. The content and the sequence of branching among stem amniotes are vigorously debated topics in early tetrapod paleontology. The ‘traditional’ stem amniote group Diadectomorpha has been proposed as the sister group of synapsid amniotes in a series of papers by one research group. If correct, the placement of Diadectomorpha within Amniota implies that high-fiber herbivory, a key component of terrestrial vertebrate ecosystems of modern aspect, is an entirely amniote phenomenon. Another stem group, Recumbirostra, has been recovered by other researchers within Amniota as reptiles. Recumbirostrans exhibit cranial features that are correlated with a fossorial lifestyle, and most species for which we have postcrania reveal the phenomena of body elongation and many of these exhibit limb reduction. If correct, the identification of recumbirostrans as early reptiles not only greatly augments the content of Paleozoic Amniota but also marks the evolution of skeletal features indicative of a burrowing lifestyle that predates the appearance of unequivocal fossorial amniotes (cistecephalid dicynodonts) by 40 million years. However, it is premature to accept either diadectomorphs or recumbirostrans as amniotes, given issues with scorings for amniote taxa, character argumentation, and poor homologization of braincase features between amniote and anamniote taxa.

Issues of Ecological Tourism Development on the Territory of Pribaikalye

Over the past few years, Russians' interest in domestic tourism has been steadily growing. This trend is due not only to external factors, but also to the initiatives of the Russian Government and governors implemented at the federal and regional levels. Tourism is becoming a strategic resource for the development of the Russian economy. The article gives examples of regions that are leaders in eco-tourism, demonstrates data confirming the development of tourism in Russian regions. Irkutsk region is characterized by the richness of flora and fauna, diversity of specially protected natural areas (SPNA). Protected areas are represented by two federal reserves (Baikal-Lensky and Vitimsky), Pribaikalsky National Park, two wildlife sanctuaries (Tofalarsky and Krasny Yar). Also in the Irkutsk region there is a part of the territory subject to protection — Lake Baikal World Natural Heritage Site. The ecosystems of protected areas are fragile in their structure, and serious interference in their structure can lead to destruction and death. Therefore, it is important to strike a balance between the development of tourism infrastructure and the preservation of natural heritage. In the world practice ecological tourism is a tool that allows designing modern ecological centers of international scale. This issue is particularly relevant for Pribaikalsky Krai; a number of documents at the federal and regional levels have identified the development of eco-tourism as one of the priority directions. In this context, it is very important to find such tools and mechanisms that will allow to preserve the environment for future generations, since the influx of tourists not only brings profit, but also leaves behind unfavorable consequences for the environment.

Soil fauna diversity is enhanced by vegetation complexity and no-till planting in regenerative agroecosystems

Agricultural ecosystems are driven by the need to increase yield, due to increased food demands. Conventional, intensive practices are not sustainable as they disrupt the biodiversity in the soil which performs a range of ecosystem functions that sustain soil productivity and resilience. Conservation agriculture and crop-livestock integrated agriculture have been promoted as some of the most sustainable and biodiversity-conserving forms of agriculture. This study assesses how soil macro-and mesofauna in staple crops respond to different agricultural land uses, including conventional, integrated and conservation agriculture, and lastly, natural grassland ecosystems which were used as reference sites. We compared species richness, composition, and functional structure of soil fauna among the land uses and assessed environmental drivers of these patterns. Soil macro-and mesofauna species richness was generally lower in conventional management compared to other management practices, for overall arthropods and for the separate taxonomic groups, beetles, earthworms, spiders, and springtails. Different functional guilds varied in their responses to the farming systems. Vegetation cover and plant litter cover are the variables which benefited most fauna diversity. The practices of no-till plantings coupled with diversified crop rotations and cover crop mixtures under conservation and integrated agricultural management enhances the diversity of earthworms, collembola, beetles, and spiders. Low-disturbance soil management, crop diversification and within-crop habitat complexity preserves arthropod soil fauna diversity in staple crops.

Diversity and species richness of avian fauna in varied habitats of Soraipung range and vicinity in Dehing Patkai National Park, India

Dehing Patkai National Park, nestled in Assam’s Upper Brahmaputra valley, features a distinctive lowland forest landscape dominated by Dipterocarpus trees, teeming with fauna encompassing reptiles, birds, and mammals. Avian surveys were conducted from October 2021 to September 2023 to document avifaunal diversity within and surrounding the park. Point-transect method was used. One-hundred-and-fifty-one species from 54 families were recorded, including 43 terrestrial and 11 aquatic bird families. One-hundred-and twenty-seven species were residents, 18 winter migrants, five summer migrants, and one was a local migrant. Habitat disturbance was assessed across five transects; undisturbed habitats in T1 and T2 showed the highest Shannon-Wiener diversity index, while moderately and highly disturbed habitats in T3, T4, and T5 exhibited lower diversity. The analysis revealed a significant positive correlation (p ≤ 0.05) among different transects. A total of seven species (Ashy-headed Green Pigeon, Lesser Adjutant, White-cheeked Partridge, Alexandrine Parakeet, Red-breasted Parakeet, Austen’s Brown Hornbill, and Oriental Darter) are classified as ‘Near Threatened’ in the IUCN Red List of Threatened species; 12 species are in Schedule 1 under the Wildlife (Protection) Act, 1972. This investigation underscores Dehing Patkai National Park’s significance as a sanctuary for diverse bird populations, including threatened and near-threatened species. The decline in bird populations in disturbed areas emphasizes the urgency of implementing effective conservation and management strategies within the park, alongside continued research and monitoring to support its unique avian ecosystem.

Climatic, oceanic, freshwater, and local environmental drivers of New Zealand estuarine macroinvertebrates

Understanding the responses of organisms to different environmental drivers is critical for improving ecosystem management and conservation. Estuarine ecosystems are under pressure from multiple anthropogenic stressors (e.g. increasing sediment and nutrient loads, pollution, climate change) that are affecting the functions and services these ecosystems provide. Here, we used long-term estuarine benthic invertebrate monitoring data (∼30 year time-series) to evaluate the responses of macrobenthic invertebrate communities and indicator species to climatic, oceanic, freshwater, and local environmental drivers in New Zealand estuaries. We aimed to improve our ability to predict ecosystem change and understand the effects of multiple environment drivers on benthic communities. Our analyses showed that the abundance and richness of macrobenthic fauna and four indicator taxa (bivalves known to have differing tolerances to sediment mud content: Austrovenus stutchburyi, Macomona liliana, Theora lubrica, and Arthritica bifurca) responded to unique combinations of multiple environmental drivers across sites and times. Macrobenthic responses were highly mixed (i.e., positive and negative) and site-dependent. We also show that responses of macrobenthic fauna were lagged and most strongly related to climatic and oceanic drivers. The way the macrobenthos responded has implications for predicting and understanding the ecological consequences of a rapidly changing environment and how we conserve and manage coastal ecosystems.

Living benthic foraminifera and organic matter compounds as proxies to characterize the trophic state in an impacted hypersaline environment: Araruama Lagoon - Brazil

Recognizing the tolerance levels of foraminifera species towards organic matter components is a crucial aspect of biomonitoring in diverse coastal environments, including hypersaline ecosystems. Despite the importance of this information, there remains limited knowledge about the biodiversity and ecological relationships of these organisms in hypersaline environments, hindering their application in biomonitoring studies. This study aimed to assess the impact of organic components on the distribution of living benthic foraminifera in the Araruama Lagoon, utilizing a comprehensive approach involving biopolymer concentration, physical-chemical parameters, and sediment grain size analyses. The results revealed a high richness of foraminiferal fauna in the lagoon, comprising 44 living species. These organisms exhibited responses indicative of anthropogenic impact, including reductions in density, diversity, and alterations in assemblage composition. Statistical analyses demonstrated that foraminiferal distribution was influenced by grain size, salinity, and organic matter concentration. Bioindicators of highly impacted areas included Ammonia tepida, Ammonia parkinsoniana, Bolivina translucens, Bolivina striatula, Elphidium excavatum, Cribroelphium gunteri and Fursenkoina pontoni. Quinqueloculina milletti and Quinqueloculina seminulum were associated with sandy areas characterized by high hydrodynamics, while Discorbis bertheloti and Valvulineria rugosa were associated to hypersaline conditions. The foraminifera distribution allowed the identification of four distinct regions within the Araruama Lagoon, each exhibiting different trophic conditions. The Environmental Quality Standards (EQS) proved effective in delineating the most environmentally compromised areas of the system. However, it was not as efficient in the characterization of the most hypersaline areas of Araruama lagoon.