scholarly journals Spatial variation in the structure of fish assemblages in the Vaalbos National Park, South Africa

Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
I.A. Russell
Keyword(s):  
Spatial Variation ◽  
National Park ◽  
Fish Assemblages ◽  
Abundant Species ◽  
Assemblage Structure ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Percentage Cover ◽  
Successful Recruitment

Fish assemblages were sampled at nine sites in the lower Vaal River in the Vaalbos National Park and adjacent properties. A total of 1543 fish from 10 species was recorded. Ordination revealed spatial variation in assemblage structure, with the distinction primarily between communities in rapids and deep pools. Flow velocity, depth and percentage cover were important determinants offish assemblage structure. The length frequency distribution of abundant species indicated successful recruitment. Several differences in the species compliment compared to earlier studies were evident, including high abundance of Barbus paludinosus and Austro^lanis sclateri, and the absence of Barbus anoplus. The length-mass relationships of large cyprmids indicated long-term declines in the physical condition of fish.

scholarly journals Interannual variability of larval fish assemblages associated with water masses in winter in the Taiwan Strait during 2007–2013

2021 ◽  
Author(s):  
Yu-Kai Chen ◽  
Chia-Yi Pan ◽  
Yi-Chen Wang ◽  
Hsiu-Ju Tseng ◽  
Bo-Kun Su ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
Taiwan Strait ◽  
Assemblage Structure ◽  
Sea Surface ◽  
Coastal Current ◽  
Annual Variations ◽  
Frontal Zones ◽  
The Taiwan Strait

AbstractIn this study, the interannual variations of ichthyoplankton assemblages in the Taiwan Strait (TS) during the winters of 2007–2013 were determined. The cold China Coastal Current (CCC) and Mixed China Coastal Water (MCCW) intruded into the TS and impinged with the warm Kuroshio Branch Current (KBC) with annual variations. Consequently, the ichthyoplankton community in the TS was mainly structured into two assemblages characterized by differing environmental conditions. The composition of the warm KBC assemblage was relatively stable and was characterized by Diaphus B and Bregmaceros spp. By contrast, the cold MCCW assemblage demonstrated considerable variations over the years, with demersal Gobiidae and Scorpaenidae families considered the most representative. In addition, Benthosema pterotum and Trichiurus spp. were common in both KBC and MCCW assemblages. The distribution of the KBC assemblage demonstrated sharp boundaries in the frontal zones, whereas changes in the assemblage structure between the frontal zones were gradual for the MCCW assemblage, particularly when demersal taxa were dominant. Sea surface temperature and salinity were most strongly associated with variability in the assemblage structure during the study period. Thus, this paper provides a better understanding of long-term larval fish dynamics during winter in the TS.

Spatial patterns in estuarine fish faunas in tropical Queensland: a reflection of interaction between long-term physical and biological processes?

1998 ◽  
Vol 49 (1) ◽  
pp. 31 ◽  
Author(s):  
Marcus Sheaves
Keyword(s):  
Fish Assemblages ◽  
Abundant Species ◽  
Common Species ◽  
Estuarine Fish ◽  
Maximum Deviation ◽  
Seawater Salinity ◽  
Spatial Differences ◽  
Upstream Direction ◽  
Catch Rates

Spatial differences in the distribution and abundance of fish faunas of structurally complex habitats in subtidal areas of three tropical estuaries were investigated by using modified Antillean-Z fish traps. The overall species compositions of the three estuaries were similar; however, the distribution and abundance of species differed substantially both within and among estuaries. Although the abundance of most species declined in an upstream direction, the fish assemblages of upstream areas of different estuaries were similar. In contrast, assemblages in seaward regions were quite distinct. Neither temperature nor turbidity were correlated with catch rates of the most abundant species. Although catch rates of some species were significantly correlated with deviation away from normal seawater salinity, in most cases the correlation with maximum deviation in salinity was much stronger. Thus, decreased catches and the absence of some common species from upstream areas may be related to the influence of long-term (months and years) patterns of salinity. Some species were abundant only in one region of a single creek. This may reflect the close proximity of nearby habitats from which recruits may come.

Records of Cholevinae (Coleoptera: Leiodidae) sampled by pitfall traps in the Central Italian Alps

2019 ◽  
Vol 13 (2) ◽  
pp. 36-42
Author(s):  
LEONARDO LATELLA ◽  
LUCA PEDROTTI ◽  
MAURO GOBBI
Keyword(s):  
Environmental Variables ◽  
National Park ◽  
Abundant Species ◽  
Species Assemblages ◽  
Pitfall Traps ◽  
Vertebrate Species ◽  
Italian Alps ◽  
Spatio Temporal ◽  
Distribution And Ecology

In the framework of a long-term project launched by the Stelvio National Park for monitoring the spatio-temporal patterns in plant, arthropod and vertebrate species assemblages, the results on the sampled cholevid species are reported. The abundance of specimens and the distribution of species has been studied in relation to nine environmental variables. Five species of the tribe Cholevini were sampled during this research: Apocatops nigrita, Catops coracinus, Catops fuliginosu, Catops nigricans and Catops tristis. The most abundant and frequent species were Apocatops nigrita and Catops coracinus. The effect of the environmental variables on the distribution of two of the most abundant species (C. coracinus, A. nigrita) was tested and described. Updated information about the distribution and ecology of the five sampled species were provided. 

Fluctuations of rodent populations in response to rainfall and fire in a central Australian hummock grassland dominated by Plectrachne schinzii

1996 ◽  
Vol 23 (3) ◽  
pp. 289 ◽  
Author(s):  
R Southgate ◽  
P Masters
Keyword(s):  
Small Mammal ◽  
National Park ◽  
Fold Increase ◽  
Abundant Species ◽  
Dry Period ◽  
Short Term ◽  
Rainfall Events ◽  
The Impact ◽  
Rodent Populations

Fluctuations in the composition and abundance of a small-mammal assemblage were studied in a hummock grassland dominated by Plectrachne schinzii at Watarrka National Park from 1988 to 1993. During this period an experiment was conducted to examine the short-term effects of fire on the rodents. We caught three species of rodent (Pseudomys hermannsburgensis, Notomys alexis and Mus domesticus). All species reached their greatest density in spring 1989 during an exceptionally wet period that extended from mid- 1988 to 1990. P. hermannsburgensis was the most abundant species and showed a 10-fold fluctuation in numbers over the sample period; N. alexis was the next most abundant species and showed a 5-fold increase but the population took longer to decline. M. domesticus was recorded only during the period of high rainfall. The number of M. domesticus was significantly less on the burnt plots than on the unburnt plots. Neither P. hermannsburgensis nor N. alexis showed significant differences between burnt and unburnt plots. This study illustrates the impact of rainfall events on the composition and density of small-mammal populations in spinifex grasslands in central Australia. Our results lead to the prediction that rodent populations will achieve densities in the order of 10 individuals ha-' or more in regions that experience three consecutive 6-month periods each with rainfall at 150% of the long-term average. This sequence apparently needs to follow a dry period where rainfall is no more than 85% of the long-term annual average for two consecutive 12-month periods.

Long term impacts of Phytophthora cinnamomi infestation on heathy woodland in the Great Otway National Park in south-eastern Australia

2020 ◽  
Vol 68 (8) ◽  
pp. 542
Author(s):  
B. A. Wilson ◽  
K. Annett ◽  
W. S. Laidlaw ◽  
D. M. Cahill ◽  
M. J. Garkaklis ◽  
...  
Keyword(s):  
National Park ◽  
Phytophthora Cinnamomi ◽  
Keystone Species ◽  
Plant Species Richness ◽  
Long Term Effects ◽  
Percentage Cover ◽  
Tea Tree ◽  
Eastern Australia ◽  
Disease Extension

The significant impacts of the introduced plant pathogen Phytophthora cinnamomi on native Australian vegetation have been well documented, but there is less knowledge of long-term effects. We assessed long-term (26 years) disease progression and impacts on vegetation floristics and structure at a heathy woodland site in the Great Otway National Park, eastern section. Disease progressed dramatically between 1989 and 2005 and by 2015 only 0.08% of the site was non-diseased. There were significant declines in plant species richness and numbers of susceptible species; and increases in percentage cover of resistant sedges and grasses overall, and in cover of Leptospermum continentale (prickly tea-tree) in post-disease areas. There were significant declines of Xanthorrhoea australis (Austral grass-tree), a keystone species that contributes greatly to vegetation structure and fauna habitat. There is an urgent need to map the distribution of P. cinnamomi affected vegetation and identify floristically important non-diseased vegetation in the national park. It is imperative that quarantine of non-infested areas, phosphite application, track closures and vehicle wash-downs be implemented to reduce disease extension and protect the significant biodiversity of the region including species rich heathlands and nationally listed threatened plant and fauna species and their habitats.

scholarly journals Fish assemblage structure in tributaries of the Meia Ponte River, Goiás, Brazil

2007 ◽  
Vol 5 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Afonso P. Fialho ◽  
Leandro G. Oliveira ◽  
Francisco L. Tejerina-Garro ◽  
Luiz C. Gomes
Keyword(s):  
River Basin ◽  
Fish Assemblage ◽  
Rainy Season ◽  
Fish Assemblages ◽  
Detrended Correspondence Analysis ◽  
Abundant Species ◽  
Assemblage Structure ◽  
Data Matrix ◽  
Sampling Station ◽  
Fish Assemblage Structure

This study was conducted in the Meia Ponte River basin, which is located in the Cerrado biome. The objective was to describe the structure of fish assemblages and to evaluate the results with the regard to the position of the tributaries (sampling stations) along the basin. This basin drains 35 municipalities of Goiás State. Springs of the Meia Ponte are located in the district of Itauçu (GO), in the Serra dos Brandões. Two sampling were conducted, one in the rainy season (March/2001) and another in the dry season (August/2001). Thirty sampling sites in tributaries and one in the channel of the Meia Ponte River, in its upper course, were selected to capture fish with dipnets (3 mm mesh) during one hour, along 100-m stretch. Sampling periods (season; rainy and dry) and the categorization according to the distance of the sampling station from the mouth of the Meia Ponte River (position; upper, intermediate and lower) were used to evaluate differences in fish assemblage structure, summarized by a detrended correspondence analysis (DCA), applied on the abundance data matrix, squared root transformed, to eliminate the effect of abundant species. The first two axes were retained for interpretation (eigenvalues = 0.35 and 0.24, for axis 1 and 2, respectively). The two-way ANOVA (factors seasons and positions) identified significant differences (p <0.05) in score averages for axis 1 and 2, for both factors. These results suggest significant differences in fish assemblage structure in the Meia Ponte River basin for the seasons (rainy and dry) and positions (upper, intermediate and lower) studied, in spite of the short spatial scale. These findings demonstrate a great ichthyofauna heterogeneity in the uppermost part of the Paraná River.

Gran Paradiso: Erkenntnisse aus der sich natürlich regulierenden Steinbockpopulation|Gran Paradiso: Conclusions from the naturally regulated Capricorn population

2007 ◽  
Vol 158 (11) ◽  
pp. 349-352
Author(s):  
Grégory Amos ◽  
Ambroise Marchand ◽  
Anja Schneiter ◽  
Annina Sorg
Keyword(s):  
Nineteenth Century ◽  
Population Density ◽  
National Park ◽  
Optimal Management ◽  
Capra Ibex ◽  
Large Fluctuations ◽  
The Alps ◽  
Gran Paradiso ◽  
Gran Paradiso National Park

The last Capricorns (Capra ibex ibex) in the Alps survived during the nineteenth century in the Aosta valley thanks to the royal hunting reservation (today Gran Paradiso national park). Capricorns from this reservation were successfully re-introduced in Switzerland after its Capricorn population had disappeared. Currently in Switzerland there are 13200 Capricorns. Every year 1000 are hunted in order to prevent a large variation and overaging of their population and the damage of pasture. In contrast, in the Gran Paradiso national park the game population regulates itself naturally for over eighty years. There are large fluctuations in the Capricorn population (2600–5000) which are most likely due to the climate, amount of snow, population density and to the interactions of these factors. The long-term surveys in the Gran Paradiso national park and the investigations of the capacity of this area are a valuable example for the optimal management of the ibexes in Switzerland.

Age and growth pattern of the thin-lipped mullet Liza Ramada in the Eastern coast of Libya.

2016 ◽  
Vol 5 (06) ◽  
pp. 4620
Author(s):  
Manal M. Khalifa ◽  
Ramadan A. S. Ali ◽  
Abdalla N. Elawad* ◽  
Mohammad El. ElMor
Keyword(s):  
Frequency Distribution ◽  
Age Groups ◽  
Age Determination ◽  
Age And Growth ◽  
Eastern Coast ◽  
Growth Equation ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Scale Reading ◽  
Von Bertalanffy Growth Equation

Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in Eastern coast of Libya. Aging was done by two methods: counting annuli on scales and by length frequency distribution, a total of 218 scales were studied for age determination, in addition of 334 fishes specimen for length frequency distribution reading. Four age groups were determined from scale reading, and five age groups from length frequency distribution methods, the parameters of the Von Bertalanffy growth equation for both sex of all individuals were estimated at 35.4 cm, 0.187 per year, -1.14 years and 2.4, for male were estimated at 35.7 cm, 0.17 per year, -1.367 and 2.3, for female were 38.6 cm, 0.156 per year, -1.383 and 2.4, for L∞, k and t0, and φ′, respectively.

scholarly journals Neelipleona and Symphypleona (Collembola) from a Sampling in the Mesovoid Shallow Substratum of the Sierra de Guadarrama National Park (Madrid and Segovia, Spain): Taxonomy and Biogeography

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 266
Author(s):  
Enrique Baquero ◽  
Rafael Jordana ◽  
Vicente M. Ortuño
Keyword(s):  
National Park ◽  
Ecological Niche ◽  
Mediterranean Area ◽  
Abundant Species ◽  
Species Level ◽  
Surface Sampling ◽  
Mesovoid Shallow Substratum ◽  
The Mediterranean

Megalothorax minimus (Neelidae) and Sphaeridia pumilis (Sminthurididae) had already been identified in surface sampling from Sierra de Guadarrama. In Europe, Sminthurinus gisini (Katiannidae) seems to be associated with environments at specific altitudes, and has little representation in this sampling. Pygmarrhopalites custodum Baquero and Jordana sp. nov. (Arrhopalitidae) coexists with two previously identified surface occurring species of the same family (P. elegans and Arrhopalites caecus). However, P. custodum is more abundant, indicating that it occupies an ecological niche tending to troglophile in the mesovoid shallow substratum (MSS). Moreover, it is also more abundant in the MSS of higher altitude corresponding to the bioclimatic zones cryo-oro-Mediterranean and oro-Mediterranean supra forest. Allacma cryptica Baquero and Jordana sp. nov. (Sminthuridae), is another species that had not been previously detected on the surface in the study area. A. cryptica is an addition to a genus which has eight described species. Gisinurus malatestai (Sminthuridae) appears well represented in the MSS, being a species present very occasionally in the Mediterranean area. Two species of the genera Sminthurides (Sminthurididae) and Fasciosminthurus (Bourletiellidae) have been found, but they could not have been identified to the species level. Finally, a few specimens of Dicyrtomina minuta (Dicyrtomidae), an abundant species on the surface, have been captured.

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