scholarly journals FISH DIVERSITY AND DISTRIBUTION IN THE AKSU RIVER ESTUARY (ANTALYA-TURKEY), IN RELATION TO ENVIRONMENTAL VARIABLES

2016 ◽  
Vol 5 ◽  
pp. 90-98
Author(s):  
Deniz İnnal
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Fish Assemblage ◽  
Seasonal Changes ◽  
Environmental Variables ◽  
Dominant Species ◽  
Seasonal Pattern ◽  
River Estuary ◽  
Fish Diversity ◽  
Liza Aurata

Seasonal changes in abundance, species composition, and life-style categories of the fish assemblage in a shallow Mediterranean estuary of southwestern Turkey are described. Fishes were sampled monthly by different nets in Aksu River Estuary from October 2006 and March 2008. In total, 3347 individuals from 26 species were captured. Mugil cephalus, Vimba vimba and Liza aurata were the dominant species and comprised over 50% of the total number. The fish comprised 10 marine, 14 freshwater and 2 migrant. The index of species richness, Shannon-wiener diversity, and evenness each showed a consistent seasonal pattern. Canonical correspondance analysis indicated that salinity correlated with the seasonal pattern in the fish assemblage.

scholarly journals Composition and diversity of anurans in the Restinga of the Conde municipality, northern coast of the state of Bahia, northeastern Brazil

2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Felipe Augusto Trindade Gondim-Silva ◽  
Alessandra Rodrigues Santos Andrade ◽  
Rafael Oliveira Abreu ◽  
Jamile Santos Nascimento ◽  
Geovane Paixão Corrêa ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Species Composition ◽  
Rainy Season ◽  
Dominant Species ◽  
The State ◽  
Northeastern Brazil ◽  
Freshwater Wetland ◽  
Northern Coast ◽  
Anuran Species

Abstract The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the 'main rainy season' and two in a 'lesser rainy season', using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H' indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones - SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones - FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H'= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H' = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga).

What drives plant biodiversity in the clay floodplain grasslands of NSW?

2009 ◽  
Vol 31 (3) ◽  
pp. 329 ◽  
Author(s):  
Tom Lewis ◽  
Peter J. Clarke ◽  
Ralph D. B. Whalley ◽  
Nick Reid
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Soil Type ◽  
Environmental Variables ◽  
Private Property ◽  
Flood Frequency ◽  
Perennial Grasses ◽  
Plant Biodiversity ◽  
South Wales ◽  
Plant Families

An assessment of the relative influences of management and environment on the composition of floodplain grasslands of north-western New South Wales was made using a regional vegetation survey sampling a range of land tenures (e.g. private property, travelling stock routes and nature reserves). A total of 364 taxa belonging to 55 different plant families was recorded. Partitioning of variance with redundancy analysis determined that environmental variables accounted for a greater proportion (61.3%) of the explained variance in species composition than disturbance-related variables (37.6%). Soil type (and fertility), sampling time and rainfall had a strong influence on species composition and there were also east–west variations in composition across the region. Of the disturbance-related variables, cultivation, stocking rate and flooding frequency were all influential. Total, native, forb, shrub and subshrub richness were positively correlated with increasing time since cultivation. Flood frequency was positively correlated with graminoid species richness and was negatively correlated with total and forb species richness. Site species richness was also influenced by environmental variables (e.g. soil type and rainfall). Despite the resilience of these grasslands, some forms of severe disturbance (e.g. several years of cultivation) can result in removal of some dominant perennial grasses (e.g. Astrebla spp.) and an increase in disturbance specialists. A simple heuristic transitional model is proposed that has conceptual thresholds for plant biodiversity status. This knowledge representation may be used to assist in the management of these grasslands by defining four broad levels of community richness and the drivers that change this status.

scholarly journals Environmental filtering and spillover explain multi-species edge responses across agricultural boundaries in a biosphere reserve

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
J. van Schalkwyk ◽  
J. S. Pryke ◽  
M. J. Samways ◽  
R. Gaigher
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Habitat Quality ◽  
Environmental Variables ◽  
Natural Habitat ◽  
Environmental Filtering ◽  
Biosphere Reserve ◽  
Natural Habitats ◽  
Habitat Specificity ◽  
Induced Changes

Abstract To ensure integrity of protected areas we need to understand how species respond to anthropogenic borders. We investigate, from a metacommunity perspective, the direct and indirect mechanisms by which transformed areas affect distribution patterns of ground-living arthropod assemblages inhabiting an extensive protected area adjacent to fruit orchards in an important biosphere reserve. Arthropods and environmental variables were sampled along transects perpendicular to natural-orchard edges. Influence of distance from orchard boundary, degree of impermeability of the boundary, orchard habitat quality (local scale land-use intensity), and edge-induced changes in local environmental variables on arthropod species richness and composition in non-crop habitats were assessed. Arthropod groups were assessed in terms of habitat fidelity: species associated with natural habitat (stenotopic species), those within crop habitat (cultural species), and those showing no preference for either habitat (ubiquitous species). Spillover resulted in higher cultural species richness near edges, but not higher overall species richness. Environmental filtering was important for stenotopic species composition, which was influenced by edge-induced changes in environmental variables. Ubiquitous species composition was determined by orchard impermeability. Increased orchard habitat quality was associated with higher cultural and ubiquitous species richness. The effects of orchards on assemblages in natural habitats can be variable, but predictable when using species habitat specificity in conjunction with a metacommunity framework. High intensity orchards may act as sink habitats, especially for species that readily disperse between crop and natural habitats. Here we recommend that local buffer strips are > 85 m wide, which will reduce the influence of cultural species spillover on sensitive natural ecosystems.

scholarly journals Fish assemblages in a tidal flat

2003 ◽  
Vol 46 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Ana Lúcia Vendel ◽  
Sabine Granado Lopes ◽  
César Santos ◽  
Henry Louis Spach
Keyword(s):  
Cluster Analysis ◽  
Community Structure ◽  
Tidal Flat ◽  
Seasonal Changes ◽  
Dominant Species ◽  
Fish Assemblages ◽  
Seasonal Pattern ◽  
Abundant Species ◽  
Structure Index ◽  
Total Capture

Studies were carried out on fish assemblages in a tidal flat. Samples were obtained monthly at low tide of the half moon in the tidal flat of Paranaguá Bay, Brazil, with two seine nets, one with a 1 mm mesh, 30 m in length and 3 m in height and another with a 10 mm mesh, 65 m in length and 2 m in height. A total of 8,890 fish were captured, comprising 24 families and 53 species. The most abundant species were Harengula clupeola and Atherinella brasiliensis, which represented 63.4% of the total, capture. A seasonal tendency was observed in the abundance of fishes, with less fishes being captured during winter and part of spring. The number of species showed a seasonal pattern, with the gradual decrease through winter and a marked increase in summer. The community structure index indicated seasonal changes in the assemblage. The faunistic similarities between months separated the 12 months into four major groups. The seasonal pattern was apparent in the numerically dominant species and the Cluster Analysis revealed five main groups.

scholarly journals Fish diversity and habitat relationship with environmental variables at Meghna river estuary, Bangladesh

2012 ◽  
Vol 38 (3) ◽  
pp. 213-226 ◽  
Author(s):  
M. Shahadat Hossain ◽  
Nani Gopal Das ◽  
Subrata Sarker ◽  
M. Ziaur Rahaman
Keyword(s):  
Environmental Variables ◽  
River Estuary ◽  
Fish Diversity

Seasonal Changes in Epipelic Diatoms Along an Intertidal Shore, Berrow Flats, Somerset

1991 ◽  
Vol 71 (3) ◽  
pp. 579-596 ◽  
Author(s):  
Deborah R. Oppenheim
Keyword(s):  
Organic Matter ◽  
Salt Marsh ◽  
Water Content ◽  
Seasonal Changes ◽  
Environmental Variables ◽  
Interstitial Water ◽  
Seasonal Pattern ◽  
Environmental Variable ◽  
Assemblage Structure ◽  
Epipelic Diatoms

Seasonal changes in the assemblage structure of dominant epipelic diatoms were studied along a transect crossing a salt marsh, sandflat, and mudflat of an estuarine intertidal shore at Berrow Flats, Somerset, UK. Seasonal changes in cell numbers displayed different patterns in the salt marsh and sandflat/mudflat. At salt marsh sites highest numbers of individuals were recorded in summer followed by a smaller autumn growth, while in the sandflat lower numbers showed no seasonal pattern. Repeated annual patterns in the succession of taxa were not observed as environmental conditions changed at the study site with time. Measurements of salinity, pH, interstitial water content, air and soil temperature were taken together with the diatom samples. A canonical correspondence analysis was employed to relate seasonal changes in assemblage structure to measured environmental variables. Total percentage variation in the first four axes of the species/site-environmental biplots ranged between 54 and 66°. In winter, sites and species separated most significantly along gradients of salinity and levels of organic matter. In spring and autumn, interstitial water content became a more significant environmental variable. By summer steep gradients in pH, levels of organic matter, and hypersaline conditions separated sites and assemblages into more discrete groups when compared to the more even spread of points in the other seasons. The results indicate that different combinations of environmental variables influence diatom assemblage structure seasonally.

scholarly journals DINÁMICA DEL FITOPLANCTON DE LA CIÉNAGA GRANDE DE SANTA MARTA, CARIBE COLOMBIANO

2016 ◽  
Vol 33 ◽  
Author(s):  
María Virginia De La Hoz Aristizbal
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Seasonal Changes ◽  
Dominant Species ◽  
General Trend ◽  
Meteorological Conditions ◽  
Phytoplankton Dynamics ◽  
Four Seasons ◽  
Low Diversity

In order to assess phytoplankton dynamics in the Ciénaga Grande de Santa Marta, bimonthly sampling was done at six stations from March 1996 to February 1997. Salinity showed wide ranges so the year could be divided in four seasons. Higher salinities were related to higher phytoplankton density, while lower salinities were related to lower phytoplankton densities and increased species richness. 224 taxa were recorded, and the general trend was towards a low diversity with a few dominant species, and most of them rare. Cyanophytes showed the highest abundances all year. Salinity, turbidity and orthophosphates were the environmental factors best related to the biotic data. Seasonal changes in phytoplankton concerning to meteorological conditions, fresh and tidal floods and dredging of Clarín canal are discussed.

scholarly journals Patterns of Pelagic Fish Diversity in Floodplain Lakes of Whitewater and Blackwater Drainage Systems Within the Central Amazon River Basin of Brazil

2021 ◽  
Vol 9 ◽  
Author(s):  
Flávia K. Siqueira-Souza ◽  
Lawrence E. Hurd ◽  
Kedma C. Yamamoto ◽  
Maria Gercilia M. Soares ◽  
Gregory J. Cooper ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
River Basin ◽  
Amazon Basin ◽  
Pelagic Fish ◽  
Floodplain Lakes ◽  
Fish Diversity ◽  
River Systems ◽  
Amazon River Basin ◽  
Central Amazon

The Amazon River Basin, one of the world’s most threatened ecosystems, has an enormous diversity of fish species, a result of temporally and spatially complex habitat containing biogeochemically different river systems. The annual hydrologic cycle results in floodplain lakes during low water and inundates forests during high water, exposing fish to different resources and environmental conditions. The two principal river systems in the central Brazilian Amazon are blackwater, with nutrient-poor acidic water, and nutrient-rich whitewater. Although species-rich, the Amazon Basin is data-poor in terms of comparative studies on a regional scale. We analyzed data sets from independent sampling studies of pelagic fish in 16 floodplain lakes, nine whitewater (Rio Solimões) and seven blackwater (Rio Negro), in the central Amazon Basin of Brazil. Our findings suggest striking similarities in pelagic fish diversity patterns. Species richness was virtually equal (165 in whitewater and 168 in blackwater). Both species richness, and number of migratory species, per lake increased toward the confluence of the rivers in both systems in our study. The proportion of unique species was also similar in whitewater lakes and blackwater (41 and 43%, respectively), boosting total regional richness to 237 species. However, species composition in whitewater lakes was more homogenous (lower β diversity), and species composition was associated with conductivity and pH in whitewater, but with dissolved oxygen and transparency in blackwater. Therefore, regional fish diversity cannot be represented by sampling one lake or even one drainage system, but must include multiple lakes from both systems. These two systems may differ in sensitivity to anthropogenic stressors such as damming and deforestation.

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