scholarly journals Population biology of the sea star Anasterias minuta (Forcipulatida: Asteriidae) threatened by anthropogenic activities in rocky intertidal shores of San Matías Gulf, Patagonia, Argentina

2017 ◽  
Vol 65 (1-1) ◽  
pp. 73 ◽  
Author(s):  
Lorena P. Arribas ◽  
María Bagur ◽  
M. Gabriela Palomo ◽  
Gregorio Bigatti
Keyword(s):  
Population Structure ◽  
Population Biology ◽  
Anthropogenic Activities ◽  
Benthic Communities ◽  
Environmental Parameters ◽  
Water Velocity ◽  
Rocky Intertidal ◽  
Anthropogenic Pressure ◽  
Sea Star ◽  
Desiccation Rate

 In Patagonian coastal areas, intertidal benthic communities are exposed to extreme physical conditions. The interaction between harsh environment and anthropogenic pressure can generate changes in population biology of marine invertebrates, like density and reproduction. The oral brooding sea star Anasterias minuta is a key organism in food chains of Atlantic Patagonian rocky intertidals, hence changes on its population structure can negatively affect shore communities. We studied the population biology of A. minuta and assess the effect of environmental parameters and anthropogenic activities on its population on rocky intertidal shores of San Matías Gulf, Patagonia, Argentina. Seasonal sea surface temperature, pH, salinity, water velocity, desiccation rate, boulders density, and anthropogenic influence (tourists and octopus fishermen) were recorded. In sites with less tourist influence and high refuge, an increase in density was recorded, especially during the summer. Brooding individuals were found in fall and winter, while feeding individuals were observed in all seasons (12 different prey, mainly the molluscs Tegula patagonica and Perumytilus purpuratus). Environmental variables such as boulders density and water velocity were the most important predictor of variation in population structure. Tourism and pH were the most important variables negatively correlated with density. Rev. Biol. Trop. 65(Suppl. 1): S73-S84. Epub 2017 November 01. 

scholarly journals Population biology of the crab Armases angustipes (Crustacea, Decapoda, Sesarmidae) at Brazilian tropical coast

2014 ◽  
Vol 104 (2) ◽  
pp. 150-161 ◽  
Author(s):  
Marina de Sá Leitão C. de Araújo ◽  
Deusinete de O. Tenório ◽  
Daniela da S. Castiglioni
Keyword(s):  
Population Structure ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Population Biology ◽  
Carapace Width ◽  
Reproductive Activity ◽  
Coastal Regions ◽  
Phytoplankton Productivity ◽  
Number Of Individuals ◽  
Tropical Coast

The semi terrestrial crabs are important elements of the fauna of coastal regions. The aim of this study was to analyze the population structure of Armases angustipes (Dana, 1852) at estuaries of the Ariquindá River, considered a non impacted area, and Mamucabas River, considered a few impacted area, on the south coast of state of Pernambuco, Brazil. The species occurred in all months of the year. The number of individuals per month varied, being higher in the months of transition between the seasons. This is probably due to significant seasonal variations of air and burrow temperature and burrow salinity. There was no sexual dimorphism in size of A. angustipes in the mangrove of Ariquindá River, but males were larger than females in the mangrove of Mamucabas River. In both estuaries, the sex ratio did not differ from Mendelian proportion, but showed a deviation for females. The analysis of temporal variation in sex ratio showed significant differences in some months of the year. These variations are due to cyclical events that act distinctly on each sex. In both estuaries, size classes of carapace width were equally represented by both sexes. The ovigerous females of A. angustipes occurred only in some months of the year, especially in summer, in both estuaries. Probably the high phytoplankton productivity observed in summer favors the reproductive activity, since these algae serve as food for the larvae. Specimens of the population of Rio Ariquindá are largest and wider than those of Mamucabas River. This fact, associated with the low abundance of crabs and the lower frequency of ovigerous females observed in Mamucabas River, is an indication that this population may be influenced by the environmental impacts that this estuary has received.

scholarly journals Succession in rocky intertidal benthic communities in areas with different pollution levels at Guanabara Bay (RJ-Brazil)

2005 ◽  
Vol 48 (6) ◽  
pp. 951-965 ◽  
Author(s):  
André Breves-Ramos ◽  
Helena Passeri Lavrado ◽  
Andrea de Oliveira Ribeiro Junqueira ◽  
Sérgio Henrique Gonçalves da Silva
Keyword(s):  
Community Development ◽  
Species Composition ◽  
Benthic Communities ◽  
Organic Pollution ◽  
Polluted Area ◽  
Rocky Intertidal ◽  
Percent Cover ◽  
Guanabara Bay ◽  
Pollution Levels ◽  
Resilient Communities

The aim of this study was to describe and compare the succession of intertidal benthic communities in two areas at Guanabara Bay, RJ, Brazil: Urca, an area submitted to moderated organic pollution and Catalão, an extremely polluted area. Three transects in each area were scraped one month before the beginning of this study in order to evaluate the recruitment (recruitment-treatments). Three other transects were monitored without manipulation (monitoring treatments). Species composition and relative abundance were evaluated monthly between September and December, 2000. A total of 26 species was found at Urca and 13 at Catalão. The percent cover of the most abundant organisms was not similar between treatments at Urca after four months, while in Catalão, the similarity was 72% in the second month. The faster community development and recovery at the most polluted area was probably related to the existence of simple and resilient communities in more impacted areas.

scholarly journals Population structure and regeneration of Himalayan endemic Larix species in three high-altitude valleys in Nepal Himalaya

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Man Kumar Dhamala ◽  
Prakash Chandra Aryal ◽  
Madan Krishna Suwal ◽  
Sijar Bhatta ◽  
Dinesh Raj Bhuju
Keyword(s):  
Population Structure ◽  
High Altitude ◽  
Graphical Representation ◽  
Anthropogenic Activities ◽  
Tree Height ◽  
Diameter Distribution ◽  
Conservation Area ◽  
Nepal Himalaya ◽  
Regeneration Status ◽  
Management Interventions

Abstract Background The Himalayan forests are of great importance to sustain the nature and community resource demands. These forests are facing pressures both from anthropogenic activities and ongoing global climatic changes. Poor natural regeneration has been considered a major problem in mountainous forests. To understand the population structure and regeneration status of Larix (Larix griffithiana and Larix himalaica), we conducted systematic vegetation surveys in three high-altitude valleys namely Ghunsa (Kanchenjunga Conservation Area, KCA), Langtang (Langtang National Park, LNP), and Tsum (Manaslu Conservation Area, MCA) in Nepal Himalaya. The average values of diameter at breast height (DBH), height, and sapling height were compared for three sites and two species using Kruskal-Wallis test. Population structure was assessed in terms of proportion of seedlings, saplings, and trees. Regeneration was analyzed using graphical representation of frequencies of seedlings, saplings, and trees in histograms. Results The results showed that the population structure of Larix in terms of the proportion of seedling, sapling, and tree varied greatly in the three study areas. KCA had the highest record of seedling, sapling, and tree compared to other two sites. Seedlings were the least among three forms and many plots were without seedlings. We found no seedling in MCA study plots. The plot level average DBH variation among sites was significant (Kruskal-Wallis χ2 = 7.813, df = 2, p = 0.02) as was between species (Kruskal-Wallis χ2 = 5.9829, df = 1, p = 0.014). Similarly, the variation in average tree height was significant (Kruskal-Wallis χ2 = 134.23, df = 2, p < 0.001) among sites as well as between species (Kruskal-Wallis χ2 = 128.01, df = 1, p < 0.001). All the sites showed reverse J-shaped curve but more pronounced for KCA and MCA. In comparing the two species, Larix griffithiana has clear reverse J-shaped diameter distribution but not Larix himalaica. Conclusion The varied responses of Larix manifested through regeneration status from spatially distinct areas show that regeneration limitations might be more pronounced in the future. In all the three studied valleys, regeneration of Larix is found to be problematic and specifically for Larix griffithiana in MCA and Larix himalaica in LNP. To address the issues of disturbances, especially serious in LNP, management interventions are recommended to sustain the unique Himalayan endemic conifer.

scholarly journals Future of Coastal Lagoons in Arid Zones under Climate Change and Anthropogenic Pressure. A Case Study from San Jose Lagoon, Mexico

Resources ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 57 ◽  
Author(s):  
Miguel Imaz-Lamadrid ◽  
Jobst Wurl ◽  
Ernesto Ramos-Velázquez
Keyword(s):  
Climate Change ◽  
Baja California ◽  
Coastal Lagoons ◽  
Anthropogenic Activities ◽  
Geospatial Analysis ◽  
Baja California Peninsula ◽  
Arid Zones ◽  
Anthropogenic Pressure ◽  
San Jose ◽  
The Future

In arid and semiarid zones, groundwater plays a key role in the ecology and availability of freshwater. Coastal lagoons in arid zones have great importance as a refuge for species of flora and fauna, as a source of freshwater, and for recreational purposes for local communities and tourism. In addition, as environments under natural stress, they are suffering pressure from anthropogenic activities and climate change, especially in zones with intense touristic development as in the case of the Baja California Peninsula in northwest Mexico. In this paper, we analyze the future of a coastal lagoon impacted by climate change and anthropogenic pressures. We constructed a groundwater MODFLOW-SWI2 model to predict changes in freshwater–saltwater inputs and correlated them with the geospatial analysis of the distribution and evolution of the water body and surrounding vegetation. The methodology was applied to the San Jose lagoon, one of the most important wetlands in the Baja California peninsula, which had been affected by anthropogenic activities and endangered by climate change. According to our water balance, the deficit of the San Jose aquifer will increase by 2040 as a result of climate change. The water table north of the lagoon will drop, affecting the amount of freshwater inflow. This reduction, together with an increase of evapotranspiration and the sea-level rise, will favor an increase of mineralization, reducing the surface water and groundwater quality and in consequence affecting the vegetation cover. Without proper management and adequate measures to mitigate these impacts, the lagoon may disappear as a freshwater ecosystem. Results of this research indicate that the use of a groundwater flow model, together with a geospatial analysis provide effective tools to predict scenarios for the future of coastal lagoons, and serve as a basis for land planning, nature conservation, and sustainable management of these ecosystems.

Seasonal variations in the water quality, diversity and population ecology of intertidal macrofauna at an industrially influenced coast

2010 ◽  
Vol 61 (6) ◽  
pp. 1505-1514 ◽  
Author(s):  
A. Vaghela ◽  
P. Bhadja ◽  
J. Ramoliya ◽  
N. Patel ◽  
R. Kundu
Keyword(s):  
Water Quality ◽  
Seasonal Variations ◽  
Anthropogenic Activities ◽  
Habitat Destruction ◽  
Anthropogenic Pressure ◽  
The North ◽  
Physico Chemical ◽  
Littoral Zones ◽  
Reported Data ◽  
Physical And Chemical

Present communication reports the physico-chemical and biological quality of seawater and status of benthos of a highly industrialized shore of the north-western coastline of India. The coastal area considered for the present study, encircled by a variety of industries, was divided into two sampling sites and monitored for two consecutive years. Results of the water quality suggest that the obtained values of the physical and chemical parameters of seawater were comparable with data reported earlier. However, data obtained in the biological parameters of the seawater showed a declining trend. Results of the intertidal macrofaunal diversity studies revealed that the muddy upper littoral zones were represented by few species of coelenterata, porifera, arthropoda and mollusca. In the rocky—muddy middle littoral zones, gastropods, stars fishes, corallites, crabs, polychetes and tubeworms were present, whereas, predominantly rocky lower littoral zones were comparatively rich in macrofaunal diversity with small patches of coral colonies. However, when the results obtained in the present study was compared with that of earlier reported data, it was clear that the macrofaunal diversity indeed declined considerably over the years. This may be due to habitat destruction and habitat alteration in the coastline caused by increased anthropogenic activities in the area. Seasonal variations in the population density and abundance were observed in most of the faunal groups except in sessile corals and sponges. This may be due to local migration of the faunal groups towards deeper regions of the Gulf, as supported by the analysis of similarity, to avoid influx of freshwater during monsoon, and high temperature during summer and post monsoon seasons. The overall assessment of different parameters of this study revealed that though the physico- chemical characteristics of the seawater did not varied much from the earlier reported status, the biological characteristics of the seawater and intertidal zone was affected possibly by a high degree of anthropogenic pressure.

scholarly journals Anthropogenic transport of species across native ranges: unpredictable genetic and evolutionary consequences

2016 ◽  
Vol 12 (10) ◽  
pp. 20160620 ◽  
Author(s):  
Jamie Hudson ◽  
Frédérique Viard ◽  
Charlotte Roby ◽  
Marc Rius
Keyword(s):  
Population Structure ◽  
Genetic Differentiation ◽  
Human Activities ◽  
Native Species ◽  
Marine Invertebrate ◽  
Anthropogenic Activities ◽  
Indigenous Species ◽  
Genetic Patterns ◽  
Geographical Distances ◽  
Anthropogenic Transport

Human activities are responsible for the translocation of vast amounts of organisms, altering natural patterns of dispersal and gene flow. Most research to date has focused on the consequences of anthropogenic transportation of non-indigenous species within introduced ranges, with little research focusing on native species. Here, we compared genetic patterns of the sessile marine invertebrate, Ciona intestinalis , which has highly restricted dispersal capabilities. We collected individuals in a region of the species' native range where human activities that are known to facilitate the artificial spread of species are prevalent. Using microsatellite markers, we revealed highly dissimilar outcomes. First, we found low levels of genetic differentiation among sites separated by both short and large geographical distances, indicating the presence of anthropogenic transport of genotypes, and little influence of natural geographical barriers. Second, we found significant genetic differentiation in pairwise comparisons among certain sites, suggesting that other factors besides artificial transport (e.g. natural dispersal, premodern population structure) may be shaping genetic patterns. Taken together, we found dissimilar patterns of population structure in a highly urbanized region that could not be predicted by artificial transport alone. We conclude that anthropogenic activities alter genetic composition of native ranges, with unknown consequences for species' evolutionary trajectories.

scholarly journals Antibiotic Resistance Genes in Phage Particles from Antarctic and Mediterranean Seawater Ecosystems

2020 ◽  
Vol 8 (9) ◽  
pp. 1293
Author(s):  
Pedro Blanco-Picazo ◽  
Gabriel Roscales ◽  
Daniel Toribio-Avedillo ◽  
Clara Gómez-Gómez ◽  
Conxita Avila ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Bacterial Communities ◽  
Anthropogenic Activities ◽  
Antibiotic Resistance Genes ◽  
Mediterranean Area ◽  
Mediterranean Coast ◽  
Anthropogenic Pressure ◽  
The Mediterranean ◽  
The Antarctic

Anthropogenic activities are a key factor in the development of antibiotic resistance in bacteria, a growing problem worldwide. Nevertheless, antibiotics and resistances were being generated by bacterial communities long before their discovery by humankind, and might occur in areas without human influence. Bacteriophages are known to play a relevant role in the dissemination of antibiotic resistance genes (ARGs) in aquatic environments. In this study, five ARGs (blaTEM, blaCTX-M-1, blaCTX-M-9, sul1 and tetW) were monitored in phage particles isolated from seawater of two different locations: (i) the Mediterranean coast, subjected to high anthropogenic pressure, and (ii) the Antarctic coast, where the anthropogenic impact is low. Although found in lower quantities, ARG-containing phage particles were more prevalent among the Antarctic than the Mediterranean seawater samples and Antarctic bacterial communities were confirmed as their source. In the Mediterranean area, ARG-containing phages from anthropogenic fecal pollution might allow ARG transmission through the food chain. ARGs were detected in phage particles isolated from fish (Mediterranean, Atlantic, farmed, and frozen), the most abundant being β-lactamases. Some of these particles were infectious in cultures of the fecal bacteria Escherichia coli. By serving as ARG reservoirs in marine environments, including those with low human activity, such as the Antarctic, phages could contribute to ARG transmission between bacterial communities.

scholarly journals Assessment of the Characteristics of Recent Major Wildfires in the USA, Australia and Brazil in 2018–2019 Using Multi-Source Satellite Products

2020 ◽  
Vol 12 (11) ◽  
pp. 1803 ◽  
Author(s):  
Mahlatse Kganyago ◽  
Lerato Shikwambana
Keyword(s):  
Forest Cover ◽  
Anthropogenic Activities ◽  
Management Strategies ◽  
Environmental Parameters ◽  
Fuel Load ◽  
Fire Intensity ◽  
Burned Area ◽  
Radiative Power ◽  
The Usa ◽  
Moderate Resolution Imaging Spectroradiometer

This study analysed the characteristics of the recent (2018–2019) wildfires that occurred in the USA, Brazil, and Australia using Moderate Resolution Imaging Spectroradiometer (MODIS) active fires (AF), fire radiative power (FRP, MW) and burned area (BA) products. Meteorological and environmental parameters were also analysed. The study found various patterns in the spatial distribution of fires, FRP and BA at the three sites, associated with various vegetation compositions, prevailing meteorological and environmental conditions and anthropogenic activities. We found significant fire clusters along the western and eastern coasts of the USA and Australia, respectively, while vastly distributed clusters were found in Brazil. Across all sites, significant fire intensity was recorded over forest cover (FC) and shrublands (SL), attributed to highly combustible tree crown fuel load characterised by leafy canopies and thin branches. In agreement, BA over FC was the highest in the USA and Australia, while Brazil was dominated by the burning of SL, characteristic of fire-tolerant Cerrado. The relatively lower BA over FC in Brazil can be attributed to fuel availability and proximity to highly flammable cover types such as cropland, SL and grasslands rather than fuel flammability. Overall, this study contributes to a better understanding of wildfires in various regions and the underlying environmental and meteorological causal factors, towards better wildfire disaster management strategies and habitat-specific firefighting.

scholarly journals Effects of human disturbance on the mongoose lemur Eulemur mongoz in Comoros: implications and potential for the conservation of a Critically Endangered species

Oryx ◽  
2015 ◽  
Vol 51 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Bakri Nadhurou ◽  
Roberta Righini ◽  
Marco Gamba ◽  
Paola Laiolo ◽  
Ahmed Ouledi ◽  
...  
Keyword(s):  
Group Size ◽  
Negative Impact ◽  
Human Impacts ◽  
Conservation Status ◽  
Environmental Parameters ◽  
Critically Endangered ◽  
Anthropogenic Pressure ◽  
Critically Endangered Species ◽  
The Impact ◽  
Group Size And Composition

AbstractThe decline of the mongoose lemur Eulemur mongoz has resulted in a change of its conservation status from Vulnerable to Critically Endangered. Assessing the current threats to the species and the attitudes of the people coexisting with it is fundamental to understanding whether and how human impacts may affect populations. A questionnaire-based analysis was used to study the impact of agriculture and other subsistence activities, and local educational initiatives, on lemur abundance, group size and composition in the Comoros. On the islands of Mohéli and Anjouan we recorded 214 lemurs in 63 groups, the size and composition of which depended both on environmental parameters and the magnitude and type of anthropogenic pressure. There was no evidence of an impact of anthropogenic disturbance on abundance. In contrast, group size and composition were sensitive to human impacts. The most important threats were conflicts related to crop raiding, as well as illegal capture and hunting. The promotion of educational activities reduced the negative impact of hunting and illegal activities. These results highlight a need for urgent conservation measures to protect the species.

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