Coastal Plain Of Southern Brazil Research Articles

Fossil Holocene Ostracoda from the Itapeva Lake, Southern Brazilian coastal plain

Holocene ostracods from a core obtained in the Itapeva Lake, Rio Grande do Sul coastal plain, are studied in this paper. Twenty-six species belonging to 22 genera and 13 families were registered in nine samples analyzed, two of them new: Cytherella eros sp. nov. and Loxoconcha itapevensis sp. nov. The taxonomic composition of the assemblages varies along the core, being Cyprideis multidentataHartmann the most abundant and frequent species (273 specimens), followed by Cytheretta punctata Sanguinetti (56 specimens) and L.itapevensis sp. nov. (51 specimens). Variation in richness and diversity observed along the core probably results from sedimentary and hydrological changes during the evolution of the Itapeva Lake. The results obtained in this work reinforce the importance of ostracods in the study of coastal paleoenvironments. Keywords: barrier-lagoon system, biostratinomy, micropaleontology, Quaternary.

Diversity and distribution of the genus Hyalella (Crustacea: Amphipoda: Hyalellidae) in temporary wetlands from the southern Brazilian Coastal Plain, with a taxonomic key to the species in the region

ABSTRACT The knowledge of the diversity and distribution of Hyalella species is scarce in the subtropical regions of Brazil. The present study investigated the diversity and distribution of Hyalella species in subtropical temporary wetlands in the southern Brazilian Coastal Plain. Six species were registered in the study region, including three new species of the genus. The spatial distribution of the species in the study region suggests that the hydrographic region (or freshwater ecoregion) is an important driver of the geographic distribution of the species. Thus, the present study increases to 19 the diversity of species with distribution in the southern region, with one new record for the state of Santa Catarina, one for the state of Rio Grande do Sul, and one for both states. We also expanded the distribution ranges of H. bonariensis, H. castroi, and H. kaingang. In addition, we elaborated a taxonomic key to the species of Hyalella known to southern Brazil. Thus, we demonstrate the need for more taxonomic studies to better understand the diversity of macroinvertebrates in Brazilian wetlands, in order to protect our fauna and contribute to the development of future conservation policies.

Middle to Late Holocene paleoenvironmental changes in the coastal plain of southern Brazil

The coastal plain of southern Brazil documents several environmental changes mainly related to sea-level fluctuation and climatic variations during the Quaternary. Comprehensive studies have been carried out, of local and regional scope, in order to improve the knowledge about the geological evolution of this portion of the South American. In this paper we present the results of stable isotope, palynological and palynofaciological analysis of the PSC-03 core (7744 cal yr BP – Modern) was performed to provide the sedimentary evolution of the Santa Catarina coastal plain. Palynological and palynofacies analyses revealed abundant and diversified palynological associations, including terrestrial palynomorphs (spores, pollen grains, fungi, and freshwater algae), marine elements (dinoflagellate cysts and foraminiferal linings), besides abundant phytoclasts and amorphous organic matter. Based on the combined analysis of δ13C isotopes (−20.7 ‰ to −29.6 ‰) and the C/N ratio (15.5–68) of the selected samples, we deduce that the organic matter is derived from marine phytoplankton and terrestrial C3 plants. The integrated approach of palynofacies and stable isotopes (δ13C and C/N) analyses revealed three distinct intervals, which characterize the environmental evolution of this portion of the coastal plain. The Interval I (7744 to 2844 cal yr BP) is related to a marginal marine environment, followed by the Interval II (2857 to 2276 cal yr BP), which indicates shallow water conditions, with wetland or soggy soils, while the Interval III (2124 cal yr BP to Modern) shows a subaerial scenario, strongly influenced by arboreal forms of the Atlantic Forest. Comparisons with other sites in southeastern South America were carried out, especially from Uruguay and Argentina, showing similarities in the palynological succession, as response to broader climatic conditions.

Late Pleistocene-Holocene diatomites from the coastal plain of southern Brazil: Paleoenvironmental implications

The southern Brazilian coastal area harbors one of the largest wetland systems of South America, important for its plant and animal biodiversity and ecosystems services provided for human populations. As an attempt to understand the development of those wetlands, samples from a diatom ooze and indurated diatomites found in the coastal plain of the state of Rio Grande do Sul were analyzed. The fragmented state of the frustules found in the samples allowed identification of most diatoms only to the genus level, nevertheless the assemblages are represented by 16 genera reported today in freshwater bodies in the studied region. The identified taxa include the planktonic Aulacoseira and Cyclotella and several benthic genera, mostly Eunotia, Pinnularia and Rhopalodia. The diatomites consist mostly of corroded irregular-shaped silica grains from frustules dissolved by alkaline water, but five diatom genera were identified. These diatomites accumulated in ephemeral ponds developed on loess sediments in dry environments and seasonal climate between the latest Pleistocene and Middle Holocene. The diatom ooze and associated organic-rich silty sediments accumulated in shallow lakes with abundant catchment vegetation and considerable dissolved organic carbon, and contain fragmented but slightly dissolved frustules as a result of hydrodynamics and low pH, and also megascleres of Porifera, cysts of Chrysophyceae, and abundant phytoliths of Poaceae. The sediment underlying the diatom ooze was dated as of 4.6–4.4 cal 14C ka BP and contains a diatom assemblage dominated by benthic epiphytic and acidophilous forms such as Eunotia, Pinnularia, and Gomphonema. The ooze and sediment overlying it contain an assemblage dominated by the planktonic Aulacoseira and Cyclotella, indicating ≥1 m-deep water column subject to moderate wind-driven hydrodynamics and variable water table. This succession shows that the development of the modern wetlands during the Middle Holocene, accompanied by the expansion of vegetation, resulted from a combination of high sea-level and increased rainfall and productivity driven by the wetter and warmer climate of the Holocene Hypsithermal, although the dense accumulation of frustules in the diatom ooze suggests a drier episode around ~4 ka BP. The results show that diatom assemblges preserved as diatomites can be used to understand the origins and response of the southern Brazilian wetlands to environmental changes, which may help address the extent of anthropogenic influence and response to future climate change, thereby contributing for the conservation and management of the coastal ecosystems.

Three new species of Hyalella (Crustacea: Amphipoda: Hyalellidae) from the Southern Brazilian Coastal Plain.

In this study, three new species of Hyalella (Crustacea: Amphipoda: Hyalellidae) are described based on specimens collected in wetlands located in three freshwater ecoregions (Southeastern Mata Atlântica, Tramandaí-Mampituba and Laguna dos Patos) of the southern Brazilian Coastal Plain (states of Rio Grande do Sul and Santa Catarina). Hyalella minuana n. sp. was recorded in the southernmost region of the state of Rio Grande do Sul. This species is characterized by presenting smooth body surface, epimeral plates not acuminated, nine serrate setae on the inner face of gnathopod 1, and peduncle of uropod 3 with four cuspidate setae with accessory seta and without plumose seta on the margin of the telson. Hyalella lagoana n. sp. was recorded in the northern region of Rio Grande do Sul and southern region of Santa Catarina. This species shows body surface smooth, epimeral plates not acuminated, nine serrate setae on the inner face of gnathopod 1, peduncle of uropod 3 with five cuspidate setae with accessory seta, and telson with six cuspidate setae with accessory seta without plumose seta on the margins. Hyalella sambaqui n. sp. was recorded in the state of Santa Catarina. This species is characterized by presenting smooth body surface, epimeral plates not acuminated, six serrate setae on the inner face of gnathopod 1, peduncle of uropod 3 with three cuspidate setae with accessory seta, and telson with three cuspidate setae with accessory seta and four plumose setae on the margin of the telson. The new records elevates the known diversity of species of Hyalella in the Brazilian territory to 33 species (19 in the southern Brazilian region) and to 83 species in the Americas.

Holocene palaeoenvironmental and palaeoclimatic reconstruction of a native ecosystem on the coastal plain of southern Brazil through multi-proxy analysis

The Butiazal de Tapes (30°31′39.86″S, 51°21′31.02″W) region is located in southern Brazil on the western shore of the Patos Lagoon and presents a remnant of a native palm grove ecosystem known as butiazal. It is characterized as savanna dominated by palm trees from the Butia genus, and spreads throughout southern Brazil, Uruguay and Argentina. Species from this genus are threatened by monoculture and livestock farming. In this region there are outcrops of Pleistocene coastal deposits which were exposed to the Holocene climate and to the influence of coastal dynamics. It is therefore an excellent location for palaeoclimatic and palaeoenvironmental reconstruction of the past 11,000 years. For such a reconstruction, and better understanding as to how this unique ecosystem was formed, tools such as bioindicators (phytoliths and palynomorphs), X-ray diffractometry analysis, total organic matter content determination, particle size analysis and carbon-14 AMS dating were used. Indications of the presence of Butia in the region from at least 11,125 to 10,751 yr cal BP were identified, along with the importance of the climate during its formation and expansion. Although the climate changes in the analysed interval were not expressive, it was possible to divide the profile into 4 zones according to plant cover and observe the influence of sea-level shifts during the Holocene on the evolution of the palaeoenvironment in the region, besides the evident human influence on vegetation evolution.

Arsenic redistributive accretion in interdune marshes and its impact on groundwater contamination of coastal plains (southern Brazil)

Excessive concentrations of arsenic in aquifers have been presented for the first time in the southern Brazilian coastal plain. In this region, the shallow aquifers are mainly constituted by a mosaic distribution of marsh sediment lenses formed in the interdune depressions in past times and subsequently covered by eolian sands. The stratigraphic descriptions and analytical determinations in water (pH, conductivity, As) and sediment (organic carbon, As, Fe, Mn) were obtained in samples of an interdune freshwater marsh, an aquifer (a palaeo-freshwater marsh), and a modern eolic dune. Principal component analysis was applied to summarize the process of As immobilization. In sediments of the modern interdune marshes and under suboxic conditions, As is mobilized from the eolic sands and its redistribution occurs along sediment profile. Its maximum concentration (up to 1.7 mg kg−1 dw) occurred at the marsh’s sediments surface and was strongly coupled to Fe hydroxides. In pore water of marshes, As has been registered up to 79 µg L−1. This enrichment was driven by reductive dissolution of As-bearing Fe hydroxides in sediments, where the reduced environment has allowed their desorption from solids as Fe(II) and As(III) reduction. After the cover of the interdune marshes by eolic sands, turning them into current aquifers, the high As contents have been maintained above the sanitary limit of 10 μg L−1 for drinking water in groundwaters. The southern Brazilian coastal plain is probably an area with arsenic contamination problem for groundwater, which deserves more attention when it is used for drinking supply.

Disentangling the role of niche-based and spatial processes on anuran beta diversity in temporary ponds along a forest–grassland transition

Evaluating beta diversity patterns along environmental gradients and different geographic ranges helps comprehend the roles of niche-based and spatial processes to metacommunity structure. Pond-breeding anuran composition depends on environmental predictors such as climate, vegetation type and habitat features as well as spatial processes (e.g., dispersal limitation or distances among patches). Here, we investigated the role of spatial and local (water chemistry and habitat structure) and regional (climate) environmental predictors to tadpole beta diversity (and its turnover and nestedness-resultant components) in temporary ponds distributed along a forest–grassland transition in the southern Brazilian Coastal Plain. Additionally, we investigated the role of the assessed predictors within forest and grassland sub-regions to test for congruence in their contribution across vegetation types. Turnover was the most relevant component of beta diversity. Spatial predictors alone explained beta diversity (and both components) at the broadest scale. However, the contribution of environmental and spatial predictors to beta diversity differed between sub-regions. Spatial and local environmental predictors independently explained beta diversity in the grassland, while in the forest sub-region, local predictors and spatially-structured climate were the most important. Our results revealed a complex interplay of niche-based and spatial assembly processes shaping anuran metacommunities. The different relationships of environmental and spatial predictors with beta diversity in the forest and grassland sub-regions suggest that the contribution of assembly processes to anuran metacommunity structure change with vegetation type.

Vegetation dynamics during the last 7500 years on the extreme southern Brazilian coastal plain

For the first time in the extreme southern Brazilian coastal plain, we analyzed palynomorphs in a continuous sequence, using an outcrop profile of relict muds in Hermenegildo Beach (33°42′12″S, 53°18′57″W), Santa Vitória do Palmar, Rio Grande do Sul state. Five radiocarbon dates were obtained. The results revealed the plant succession in an ancient water reservoir near the coastal line. 7500–4000 BP: Marine organisms and freshwater taxa, with herbaceous marsh at the margins. Marine taxa were markedly present from 6000 to 5000 BP, the time of the maximum transgression. Regionally, the vegetation was dominated by grasslands and forest groupings. 4000–2000 BP: Regressive marine phase, with an increased record of freshwater organisms due to increased rainfall. A large increase in herbaceous marsh components resulted in a gradual filling-in of the water reservoir and the development of regional vegetation. 2000–1760 BP: With the end of the marine regression, progressive desalinization promoted the local herbaceous marsh development. Regionally, grassland and forest also developed, indicative of climate amelioration. Local plant succession ceased during this phase of herbaceous marsh ca. 1760 BP, when beach sands covered the sedimentary sequence. This study reveals the phases of a hydrosere in a coastal water reservoir, influenced by marine oscillations, with gradual desalinization and filling-in that culminated in an herbaceous marsh deposit. These results provide a basis for understanding many other similar relict muds spread throughout the coastal plain in the extreme south of Brazil.

On the presence of Megatherium Cuvier, 1796 (Xenarthra, Pilosa) in fossiliferous deposits of the Coastal Plain of Southern Brazil

The presence of the extinct sloth Megatherium americanum Cuvier in Pleistocene deposits of the Coastal Plain of the State of Rio Grande do Sul, southern Brazil, has been mentioned by several authors for decades, but formal descriptions of skeletal elements with unambiguous diagnostic features have never been published. The recent description of one dentary of the megatheriid Eremotherium laurillardi Lund from deposits in this area raised doubts about the taxonomic affinity of the materials assigned to M. americanum. The present work confirms the presence of the latter in the coastal plain of the state of Rio Grande do Sul (Santa Vitoria do Palmar County), from a partial skull collected in fluvial deposits of the Santa Vitoria Formation exposed on the banks of the Chui Creek, plus an incomplete dentary, one tibia, one astragalus found on the shoreline, and another tibia with the fibula fused proximally and distally retrieved from the bottom of the continental shelf by the research vessel “Atlântico Sul”. The fossils of both species of megatheriid sloths were found in the same deposits of Rio Grande do Sul (Chui Creek in the coastal plain and Pessegueiro Creek in the central area of the state), which is remarkable given that E. laurillardi is known mostly from the intertropical Americas, whereas M. americanum is restricted to the subtropical-temperate regions of South America. Such co-occurrence could indicate that both species were sympatric or be related to the mixing by fluvial processes of remains of animals that occupied the same areas at distinct times due to periodic latitudinal shifts of the climatic belts.

Identification of the agonist of trace amine-associated receptor 5 (TAAR5) and its action on brain physiology and neurochemistry

New geological analysis of the Ravenna coastal plain has allowed a major update of the geological coastal model, with anthropogenic overprints removed from an area heavily affected by human actions in the last four centuries, a period in which the Little Ice Age (LIA) has had a large influence on the coastal dynamics. The geological build-up of the coastal plain is a natural occurrence that is important for understanding the present-day coastal buildup. However, coastal zone anthropization has defined the actual coastal morphology, canceling out most of surface expression needed to create an accurate coastal evolution model, as the beach ridges morphology in the study area. As the lack of surface expression due to the anthropogenic actions has changed the coastal zone under study, it is not possible to only use geomorphological analysis to construct a local coastal evolution model. Because of this, building a new model and understanding how coastal evolution would proceed without human influence would allow us to understand the interaction between natural forces and anthropogenic influence, which has acted to shape the actual morphology of the study area from the LIA period to the present days. We therefore propose an integration of data using the following: actual data from the surface, such as the high-resolution digital surface model (DSM) and the digital terrain model (DTM); the actual database from the Emilia-Romagna Region Geological Survey, including the shapefile with the regional soil chart and the geological elements present in the study area; knowledge from previous work carried out in the area; and the subsurface data from Ground Penetrating Radar (GPR), which would make the study the first to use a GPR survey of the coastal plain of the northwest Adriatic. In addition, the work will follows a successful case study done in the southern Brazilian coastal plain that integrated previous works done in the coastal plain with new methods such as GPR data acquisition. The GPR data allows for corroboration of the interpretation of the coastal model constructed using the surface data. Finally, the surface geological model proposed in this work may aid by providing the following: i) a new means for local coastal geology research; ii) a methodology to apply to other barrier-lagoon systems around the world in order to update our knowledge about these systems; and iii) powerful information to support coastal managers and decision makers in constructing a long-term master plan for effective Integrated Coastal Zone Management.

Late-Holocene subtropical mangrove dynamics in response to climate change during the last millennium

This work aims to study the impacts of climate change in the subtropical mangroves during the late-Holocene on a southern Brazilian coastal plain and discuss the environmental conditions to the mangrove establishment near the austral limit of South America mangroves. Samples were collected to study palynological groups, sedimentary facies, and geochemistry analyses (δ13C, δ15N, TOC, TN, C:N ratio, TS, and C:S ratio), synchronized with four radiocarbon ages. The main result of this research was the mangrove succession, divided into three palynological zones composing two facies association: (1) herbaceous tidal flat and (2) mangrove tidal flat. The first zone between at least ~1815 and ~1629 cal. yr BP was marked by the mangrove absence with marine particulate organic carbon, C3 terrestrial plants, and macrophytes organic matter influence with δ13C values between −26.7‰ and −20‰, δ15N values x̅ = 3.5‰ and C:N around 21.8. The second zone between ~1629 and ~853 cal. yr BP was marked by the mangrove establishment represented only by Laguncularia pollen under influence of estuarine organic matter (δ13C x̅ = −26.5‰; δ15N x̅ = 3.2‰, and C:N around 16.4). The third zone reveals an increase of Laguncularia and presence of Avicennia pollen since ~853 cal. yr BP. Near the surface (<10 cm) occurs Rhizophora pollen, indicating the establishment of this genus during the past decades, under the modern environmental condition (δ13C x̅ = −27.02‰; δ15N x̅ = 3.12‰, and C:N around 17.42). This mangrove vertical succession may be associated with the low-temperature tolerance, where the sequence Rhizophora, Avicennia, and Laguncularia occurs from the northern to the southern limits of Santa Catarina coast, respectively, reflecting the temperature gradient. Therefore, probably, the establishment of the mangrove assemblage identified along the studied pollen profile was influenced by a temperature increase of air and water during the late-Holocene and, considering the Rhizophora genus, only during the past decades.

Molluskan Grazing Traces (Ichnogenus Radulichnus Voigt, 1977) on a Pleistocene Bivalve from Southern Brazil, With the Proposal of a New Ichnospecies

The ichnogenus Radulichnus Voigt, 1977 is recorded for the first time from a bivalve, Anomalocardia brasiliana (Gmelin, 1791), in a late Pleistocene molluskan assemblage from the southern Brazilian coastal plain. Grazing traces comprise short (<1 mm), parallel furrows, arranged in rows on the inner (concave) shell surface and mostly concentrated in its central area. Radulichnus accommodates scratches on hard substrates produced by the radula of grazing gastropod or polyplacophorans. Our literature survey on fossil and extant traces, as well as studies on the grazing mechanism in living mollusks, document at least two distinct morphotypes that are related to differences in the feeding modes of the producers. We propose to distinguish a second ichnospecies of Radulichnus, in addition to the type, R. inopinatus Voigt, 1977 (produced by gastropods), which is named R. transversus isp. nov., and attributed to polyplacophorans. Grazing traces on the shell of A. brasiliana match the morphotype produced by polyplacophorans mollusks, and are indicative of its complex taphonomic history in comparison with other shells in this assemblage.

New Insights on the systematic classification of certain palynological taxa (tintinnomorphs) from Holocene deposits of the Coastal Plain of Southern Brazil

New Insights on the systematic classification of certain palynological taxa (tintinnomorphs) from Holocene deposits of the Coastal Plain of Southern Brazil

Six freshwater microturbellarian species (Platyhelminthes) in&amp;nbsp;permanent wetlands of the Coastal Plain of southern Brazil: new&amp;nbsp;records, abundance, and distribution

Microturbellarians occur in a wide range of ecosystems, but their diversity and distribution are largely unknown. In this&nbsp;work, we report on the morphology, abundance, and distribution of 6 species of microturbellarians, namely Baicalellia&nbsp;evelinae, Catenula evelinae, C. leuca, C. turgida, Gieysztoria chiqchi, and Stenostomum hemisphericum. We provide&nbsp;photographs and schematic drawings of the specimens in vivo. Three of them were known only for their type localities. Most species showed low to moderate abundance and were found in a single wetland in this study. Gieysztoria chiqchi&nbsp;is reported from Brazil for the first time. All records extend the ranges of the species at least 800 km to the southeast.

Interspecific interactions may not influence home range size in subterranean rodents: a case study of two tuco-tuco species (Rodentia: Ctenomyidae)

Coexistence between species with similar niche requirements is often facilitated by displacement of morphological, behavioral, or physiological characteristics. Experiments comparing treatments with and without the presence of potential competitors are ideal for testing hypotheses of interspecific competition. Here, we investigate a fundamental aspect in the natural history of a species: the home range. We determined whether co-occurrence can influence the home range size of 2 subterranean rodent species, Ctenomys flamarioni and C. minutus. We evaluated home range size in populations of both species in allopatry and sympatry along the coastal plain of southern Brazil. Animals were radiotracked, and the home range size of each individual was estimated using grid cells and minimum convex polygon methods. We found no significant differences in home range size between sites or species, and the interaction was nonsignificant. We also found no relationship between home range size and body mass or sex. Our results suggest that co-occurrence may not influence home range size in these species, perhaps due to environmental adaptations that facilitate coexistence (e.g., microhabitat segregation and dietary modifications). Further, the characteristics of the sandy dune habitat may act as environmental filters, favoring similar home range sizes for both species. A coexistência entre espécies com requerimento similares de nicho é normalmente facilitada por deslocamento de caractere morfológico, comportamental ou fisiológico. Experimentos comparando tratamentos com e sem a presença de competidores potenciais são ideais para testar hipóteses sobre competição interespecífica. Neste estudo nós investigamos um aspecto fundamental da história natural de uma espécie: a área de vida. Nós determinamos se a co-ocorrência pode influenciar no tamanho da área de vida de dois roedores subterrâneos, C. flamarioni e C. minutus. Para isso foi avaliado o tamanho da área de vida em populações das duas espécies em locais onde se distribuem de forma alopátrica e simpátrica, ao longo da planície costeira do extremo sul do Brasil. O tamanho da área de vida de cada animal foi estimado utilizando os métodos de grid de células e mínimo polígono convexo, por meio da utilização de rádios colares fixados em cada indivíduo. Os resultados não apontaram nenhuma diferença significativa no tamanho da área de vida entre os sítios ou espécies, e as interações entre eles também não foi significativa. Além disso, não foi encontrado relação entre tamanho da área de vida com massa corporal ou sexo. Nossos resultados sugerem que a co-ocorrência pode não influenciar o tamanho da área de vida das espécies, isto pode se dá devido a adaptações ambientais que facilitam a coexistência (por exemplo, segregação de microhabitat e modificações na dieta). Além disso, as características do habitat de dunas arenosas podem atuar como filtro ambiental, favorecendo tamanhos semelhantes de área de vida em ambas as espécies.

Paleoenvironmental evolution of the coastal plain of Southern Brazil: palynological data from a Holocene core in Santa Catarina State.

This paper presents a paleoenvironmental reconstruction from palynological analyses of a sedimentary core of Holocene age, drilled at municipality of Garopaba (Santa Catarina), Southern Brazil. A total of 46 samples was collected for palynological analyses in the 450 cm-long core PCSC-3, as also three samples for radiocarbon dating and granulometric analyses. The palynological content includes 84 taxa related to pollen grains of angiosperms (38) and gimnosperm (3), spores of pteridophyta (16) and bryophyta (2), spores of fungi (8), algae (3), acritarchs (3), dinoflagellate cysts (2) and microforaminiferal linings (1). Three specimens of acritarchs are described and illustrated in detail. Three palynological phases were defined based on changes in assemblages: Phase I, Phase II and Phase III. The Phase I is characterized as a lagoonal paleoenvironment with marine influence from the beginning of the sedimentation (5390 cal yr BP), based on occurrences of acritarchs, dinoflagellate cysts and microforaminiferal linings. The Phase II (3032 yr BP until 858 cal yr BP) also is characterized by a lagoonal paleoenvironment, however, presented decrease in percentage of marine elements and increase in freshwater algae record, suggesting less marine influence in the lagoonal body. In Phase III (last 856 years), underwater sedimentation prevailed, under swamp-like conditions.

What does the Southern Brazilian Coastal Plain tell about its diversity? Syrphidae (Diptera) as a model.

The natural areas of the Coastal Plain of Rio Grande do Sul (CPRS) have suffered fragmentation due to anthropic action. The faunal surveys offer a low-cost method to quickly evaluate environmental alterations, and Syrphidae flies are often used as models in this kind of study. We aimed to ascertain the diversity of Syrphidae in the South region of Brazil by estimating its species' richness, and to use this data to identify new areas for conservation. In this survey Malaise traps were installed for 8 days in the CPRS, which was divided into five regions. Each region was subdivided into seven collecting areas and each of those areas received four traps, totaling 140 traps. A total of 456 Syrphidae individuals from 18 genera and 49 species were collected. In Region 1, there were nine exclusive species; in Region 2, there were three; in Region 3, there were 13, ten of which came from Estação Ecológica do Taim (ESEC Taim). In the Individual-based rarefaction analysis, Region 1 possessed the largest number of expected species out of the regions in the CPRS; we found 97% of these species. This insect collection effort, as one of the first in the CPRS, has broadened the known geographic distributions of 11 species of Syrphidae, and also indicated areas to be conserved. Additionally, it gave support for expanding ESEC Taim and creating new areas of conservation in Region 1, in Arroio Pelotas and Arroio Corrientes.

Ontogenetic variations and feeding habits of a Neotropical annual fish from southern Brazil

ABSTRACT Knowing the feeding biology of a population and its ontogenetic aspects can help in understanding the functioning of fish assemblages, essential to the conservation of the habitat biodiversity in which these species are found. Annual fishes complete their life cycle in temporary aquatic environments, existing in adult stage only for brief annual periods. Changes in the feeding habits between different size classes could indicate that a species belongs to different feeding groups in different growth phases. The aim of this work was to characterize the diet of Cynopoecilus fulgens Costa, 2002 in a temporary flooded area in the coastal plain of southern Brazil, taking into consideration possible alterations in feeding habits in different body size classes caused by ontogenetic changes, to explain the coexistence of these individuals in a short space of time. The diet analysis indicated that C. fulgens is a generalist, consuming small crustaceans and autochthonous insects. Intraspecific differences in diet were determined when compared between nine classes of standard length. Adults fed mainly on autochthonous insects, and juveniles ingested mostly crustaceans, with the population being separated into two trophic groups: invertivores and invertivores with a tendency towards zooplanktivory. It is possible to conclude that the ontogenetic changes in the diet of C. fulgens are related to morphological restrictions due to the size of the individuals, since feeding competitive relations are probably not so evident.

Surface and subsurface data integration and geological modelling from the Little Ice Age to the present, in the Ravenna coastal plain, northwest Adriatic Sea (Emilia-Romagna, Italy)

New geological analysis of the Ravenna coastal plain has allowed a major update of the geological coastal model, with anthropogenic overprints removed from an area heavily affected by human actions in the last four centuries, a period in which the Little Ice Age (LIA) has had a large influence on the coastal dynamics. The geological build-up of the coastal plain is a natural occurrence that is important for understanding the present-day coastal buildup. However, coastal zone anthropization has defined the actual coastal morphology, canceling out most of surface expression needed to create an accurate coastal evolution model, as the beach ridges morphology in the study area. As the lack of surface expression due to the anthropogenic actions has changed the coastal zone under study, it is not possible to only use geomorphological analysis to construct a local coastal evolution model. Because of this, building a new model and understanding how coastal evolution would proceed without human influence would allow us to understand the interaction between natural forces and anthropogenic influence, which has acted to shape the actual morphology of the study area from the LIA period to the present days. We therefore propose an integration of data using the following: actual data from the surface, such as the high-resolution digital surface model (DSM) and the digital terrain model (DTM); the actual database from the Emilia-Romagna Region Geological Survey, including the shapefile with the regional soil chart and the geological elements present in the study area; knowledge from previous work carried out in the area; and the subsurface data from Ground Penetrating Radar (GPR), which would make the study the first to use a GPR survey of the coastal plain of the northwest Adriatic. In addition, the work will follows a successful case study done in the southern Brazilian coastal plain that integrated previous works done in the coastal plain with new methods such as GPR data acquisition. The GPR data allows for corroboration of the interpretation of the coastal model constructed using the surface data. Finally, the surface geological model proposed in this work may aid by providing the following: i) a new means for local coastal geology research; ii) a methodology to apply to other barrier-lagoon systems around the world in order to update our knowledge about these systems; and iii) powerful information to support coastal managers and decision makers in constructing a long-term master plan for effective Integrated Coastal Zone Management.