scholarly journals Status of aquatic and riparian biodiversity in artificial lake ecosystems with and without management for recreational fisheries: implications for conservation

2019 ◽  
Author(s):  
Robert Nikolaus ◽  
Malwina Schafft ◽  
Andreas Maday ◽  
Thomas Klefoth ◽  
Christian Wolter ◽  
...  

AbstractHumanity is facing a biodiversity crisis, with freshwater-associated biodiversity in a particularly dire state. Novel ecosystems created through human use of mineral resources, such as gravel pit lakes, can provide substitute habitats for conservation of freshwater and riparian biodiversity. However, many of these artificial ecosystems may exhibit high recreational use intensity, which may limit their biodiversity potential.The species richness of several taxa (plants, amphibians, dragonflies, damselflies, waterfowl, songbirds) was assessed and a range of taxonomic biodiversity metrics were compared between gravel pit lakes managed for recreational fisheries (N = 16) and unmanaged reference lakes (N = 10), while controlling for non-fishing related environmental variation.The average species richness of all examined taxa was similar among both lake types and no substantial differences in species composition were revealed when examining the pooled species inventory. Similarly, there were no differences among lake types in the presence of rare species and in the Simpson diversity index across all the taxa that were assessed.Variation in species richness among lakes was correlated with woody habitat, lake morphology (surface area and steepness) and land use, but not correlated with the presence of recreational fisheries. Thus, non-fishing related environmental variables had stronger effects on local species presence than recreational-fisheries management or the presence of recreational anglers.Collectively, no evidence was found that anglers and recreational-fisheries management constrain the development of aquatic and riparian biodiversity in gravel pit lakes in the study region. Conservation of species diversity at gravel pit lakes could benefit from an increasing reliance on habitat enhancement activities.

2018 ◽  
Author(s):  
S. Matern ◽  
M. Emmrich ◽  
T. Klefoth ◽  
C. Wolter ◽  
N. Wegener ◽  
...  

AbstractGravel pit lakes constitute novel ecosystems that can be colonized by fishes through natural or anthropogenic pathways. Many of these man-made lakes are used by recreational anglers and experience regular fish stocking. Recreationally unmanaged gravel pits may also be affected by fish introductions, e.g., through illegal fish releases, thereby contributing to the formation of site-specific communities. Our objective was to compare the fish biodiversity in gravel pit lakes with and without the recent influence of recreational fisheries management. We sampled 23 small (< 20 ha) gravel pit lakes (16 managed and 7 unmanaged) in north-western Germany and compared fish community and diversity metrics obtained using littoral electrofishing and multimesh gillnet catch per unit effort data. Given the size of the lakes we sampled we expected species poor communities and elevated fish diversity in the managed systems due to stocking. The two lake types were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Both lakes types hosted similar fish abundance and biomass, but were substantially different in terms of the fish community structure and species richness. Fish were present in all lakes with at least three species. We discovered a higher α-diversity and a lower β-diversity in managed gravel pit lakes compared to unmanaged lakes. Thus, recreational fisheries management appeared to foster homogenization of fish communities, likely because fisheries managers stock these lakes with desired fish species (e.g., piscivorous fishes and large bodied cyprinids). However, we also detected anthropogenic pathways in the colonization of unmanaged gravel pit lakes, presumably from illegal releases by private people. Importantly, hardly any non-native species were detected in the gravel pits we studied, suggesting that recreational fisheries management not necessarily promotes the spread of exotic species.Significance StatementLittle is known about fish communities in artificially created gravel pit lakes. We compared those managed by recreational fishers with those lacking fisheries management in north-western Germany. We found fishes in all gravel pit lakes and demonstrated a higher α-diversity but more homogenized fish communities in managed gravel pit lakes compared to unmanaged lakes. We did not detect the establishment of relevant abundances of non-natives fishes despite intensive fisheries management.


Author(s):  
M. A. Gondal ◽  
S. Iqbal ◽  
U. Atique ◽  
N. U. Saher ◽  
N. A. Qureshi ◽  
...  

Abstract The primary objective of this study was to investigate the seasonal fish and crustacean variations concerning taxonomic composition, species richness, and diversity in sandy beach habitat. For this purpose, we investigated the Sonmiani Hor lagoon area during four distinct seasons, i.e., northeast (NE) monsoon, pre-monsoon, south-west (SW) monsoon, and post-monsoon for one year. During each haul, the net was pulled about 100m along the beach in 0.5m depth. The results showed a strong linear correlation between the diversity index and equitability in fishes (r = 0.978). The diversity index was strong negatively correlated with the abundance and biomass (r = -0.978, -0.972, respectively). The physical attributes like sea surface water temperature and salinity showed a strong negative effect on species assemblages (r = -0.981 and -0.943, respectively). The mean air and water temperature illustrated approximately 3°C difference during NE and pre-monsoon seasons. However, salinity, pH, and electrical conductivity did not show any significant seasonal variabilities. Under the ecological indices, the fish species displayed higher diversity (H’ = 3.19) during SW monsoon, whereas the lowest diversity was observed during pre-monsoon (H’ = 1.58). The equitability and species richness, however, remained more noticeable during SW monsoon (J’ = 0.81). The total number of individuals of fish and crustaceans reached 4799 with 3813 fish individuals and 986 individuals of crustaceans. A total of 27 families of fish while five crustacean families comprising of 30 genera and 38 fish species while ten genera and 17 species of crustaceans were recorded. Liza subviridis displayed the highest abundance among the sampled fish species. In conclusion, fish species constituted a significant part of the coastal fauna in the study area. The seasonal variations displayed distinct variations in fish species composition and diversity.


2017 ◽  
Vol 14 (2) ◽  
pp. 1 ◽  
Author(s):  
Noor Nasuha Abd Aziz ◽  
Siti Khairiyah Mohd Hatta ◽  
Idris Abd Ghani ◽  
Saiyid Jalaluddin Saiyid Shaifuddin

A study on abundance and diversity of Hymenoptera was conducted in Gunung Datuk, Rembau. Samplings were conducted from November 2014 to February 2015 using six Malaise traps. Three traps were placed at Site 1 at 700m height for high elevation and the remaining traps were placed at Site 2 at 200m height for low elevation. A total number of 221 Hymenopteran were collected which consist of nine families namely Ichneumonidae, Formicidae, Braconidae, Bethylidae, Evaniidae, Tiphiidae, Vespidae, Pompilidae and Apidae. In this study, 93 individuals were obtained from Site 1, comprising nine families and 43 morphospecies while 127 individuals were obtained from Site 2 with nine families and 45 morphospecies. Formicidae was the most dominant family collected from both sites with a total of 104 individuals while the least family recorded was Apidae with only one individual. Shannon’s Weiner Diversity Index (H’) showed Site 1 had the higher diversity value with H’ = 3.17 compared to Site 2 with value H’ = 3.12. For Evenness Index, Site 1 had higher value compared to Site 2 with E’ = 0.84 and E’ = 0.82 respectively. Moreover, for Margalef Richness Index, Site 1 recorded R’ = 9.24 while site two recorded R’ = 9.08 which concluded that Site 1 had higher species richness compared to Site 2. Paired t-test showed that both sites had no significant difference with p>0.05. Overall study showed that the diversity and abundance of Hymenoptera in Gunung Datuk were low since the value of H’ is less than 3.50.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Peter Halvarsson ◽  
Johan Höglund

Abstract Background A novel way to study the species composition and diversity of nematode parasites in livestock is to perform deep sequencing on composite samples containing a mixture of different species. Herein we describe for the first time the nematode community structures (nemabiomes) inhabiting Swedish sheep and how these are/were affected by host age and recent anthelmintic treatments. Methods A total of 158 fecal samples were collected (n = 35 in 2007 and n = 123 in 2013–2016) and cultured from groups of sheep on 61 commercial farms in the south-central part of the country where most animals are grazed. Among the samples, 2 × 44 (56%) were paired collections from the same groups pre- and post-treatment with anthelmintics such as macrocyclic lactones, benzimidazoles or levamisole. Samples were analyzed for their nemabiome using the PacBio platform followed by bioinformatic sequence analysis with SCATA. Species richness and diversity were calculated and analyzed in R. Results Nematode ITS2 sequences were found in all larval culture samples except two, even though the fecal egg counts were below the McMaster threshold in 20 samples. Sequencing yielded, on average, 1008 sequences per sample. In total, 16 operational taxonomical units (OTU), all with ≥ 98 % identity to sequences in the NCBI database, were recognized. The OTUs found represented nematode species of which ten are commonly associated with sheep. Multiple species were identified in all pre-anthelmintic treatment larval culture samples. No effects on nematode diversity were found in relation to host age. On the other hand, recent anthelmintic treatment lowered species richness, especially after use of ivermectin and albendazole. Interestingly, despite zero egg counts after use of levamisole, these samples still contained nematode DNA and especially H. contortus. Conclusions Our findings provide evidence that nemabiome analysis combined with diversity index analysis provides an objective methodology in the study of the efficacy of anthelmintic treatment as both high and low abundant species were detected.


2017 ◽  
Vol 63 (2) ◽  
pp. 8-16 ◽  
Author(s):  
Corrado Battisti ◽  
Marco Giardini ◽  
Francesca Marini ◽  
Lorena Di Rocco ◽  
Giuseppe Dodaro ◽  
...  

We reported a study on breeding birds occurring inside an 80 m-deep karst sinkhole, with the characterization of the assemblages recorded along its semi-vertical slopes from the upper edge until the bottom. The internal sides of the sinkhole have been vertically subdivided in four belts about 20 m high. The highest belt (at the upper edge of the cenote) showed the highest values in mean number of bird detections, mean and normalized species richness, and Shannon diversity index. The averaged values of number of detections and species richness significantly differ among belts. Species turnover (Cody’s β-diversity) was maximum between the highest belts. Whittaker plots showed a marked difference among assemblages shaping from broken-stick model to geometric series, and explicited a spatial progressive stress with a disruption in evenness towards the deepest belts. Bird assemblages evidenced a nested subset structure with deeper belts containing successive subsets of the species occurring in the upper belts. We hypothesize that, at least during the daytime in breeding season, the observed non-random distribution of species along the vertical stratification is likely due to (i) the progressive simplification both of the floristic composition and vegetation structure, and (ii) the paucity of sunlight as resources from the upper edge to the inner side of the cenote.


Water ◽  
2016 ◽  
Vol 8 (9) ◽  
pp. 409 ◽  
Author(s):  
Pauline Mollema ◽  
Marco Antonellini ◽  
Alwin Hubeek ◽  
Peter Van Diepenbeek

2016 ◽  
Vol 51 (8) ◽  
pp. 958-966 ◽  
Author(s):  
Anderson Pedro Bernardina Batista ◽  
José Márcio de Mello ◽  
Marcel Régis Raimundo ◽  
Henrique Ferraço Scolforo ◽  
Aliny Aparecida dos Reis ◽  
...  

Abstract: The objective of this work was to analyze the spatial distribution and the behavior of species richness and diversity in a shrub savanna fragment, in 2003 and 2014, using ordinary kriging, in the state of Minas Gerais, Brazil. In both evaluation years, the measurements were performed in a fragment with 236.85 hectares, in which individual trees were measured and identified across 40 plots (1,000 m2). Species richness was determined by the total number of species in each plot, and diversity by the Shannon diversity index. For the variogram study, spatial models were fitted and selected. Then, ordinary kriging was applied and the spatial distribution of the assessed variables was described. A strong spatial dependence was observed between species richness and diversity by the Shannon diversity index (<25% spatial dependence degree). Areas of low and high species diversity and richness were found in the shrub savanna fragment. Spatial distribution behavior shows relative stability regarding the number of species and the Shannon diversity index in the evaluated years.


2018 ◽  
Vol 27 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Bojan Damnjanović ◽  
Maja Novković ◽  
Aleksandra Vesić ◽  
Milica Živković ◽  
Snežana Radulović ◽  
...  

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