scholarly journals Spatial and temporal variation of fish assemblages in a subtropical small stream of the Huangshan Mountain

2010 ◽  
Vol 56 (6) ◽  
pp. 670-677 ◽  
Author(s):  
Yunzhi Yan ◽  
Shan He ◽  
Ling Chu ◽  
Xiuying Xiang ◽  
Yanju Jia ◽  
...  
Keyword(s):  
Species Richness ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Fish Assemblages ◽  
Spatial And Temporal Variation ◽  
Scaling Analysis ◽  
Small Stream ◽  
Study Sites ◽  
Species Richness And Abundance ◽  
Huangshan Mountain

Abstract Spatial and temporal variation of fish assemblages were investigated seasonally from May 2007 to February 2008 across 11 study sites in a subtropical small stream, the Puxi Stream, of the Huangshan Mountain. Along the longitudinal gradient from headwater to downstream, fish species richness and abundance increased gradually, but then decreased significantly at the lower reaches. The highest species richness and abundance were observed in August and the lowest in February. Based on analysis of similarities (ANOSIM), fish assemblages were significantly different in spatial variation but not in temporal variation. Although differences were observed both among sites and among stream orders, the lower R value in order-variation suggested stream order was not the optimal factor explaining the spatial variation of fish assemblages. In addition, dam construction did not significantly alter fish assemblages in the sites adjacent to and immediately downstream to dams. Using cluster analysis and non-metric Multi Dimensional Scaling analysis (NMS), assemblages were separated into three groups at a Bray-Curtis similarity value of 42%: the upper, middle and lower groups. Following analysis of similarity percentages of species contributions (SIMPER), shifts in occurrence or abundance of S. curriculus, Z. platypus, R. bitterling and A. fasciatus contributed most to the differences amongst the three groups. Standard Deviation Redundancy Analysis (RDA) suggested that habitat structure (such as elevation, substrate, and flow velocity) contributed to the spatial and temporal pattern of fish assemblages in the Puxi Stream. In conclusion, the fish assemblages in Puxi Stream presented significant spatial but not temporal variation. Human disturbance has perhaps induced the decrease in species diversity in the lower reaches. However, no significant change was observed for fish assemblages in sites far from and immediately downstream from low-head dams.

A review of spatial and temporal variation in grey and common seal diet in the United Kingdom and Ireland

2012 ◽  
Vol 92 (8) ◽  
pp. 1711-1722 ◽  
Author(s):  
Susie L. Brown ◽  
Stuart Bearhop ◽  
Chris Harrod ◽  
Robbie A. McDonald
Keyword(s):  
Spatial Variation ◽  
Temporal Variation ◽  
Large Scale ◽  
Fish Assemblages ◽  
Prey Availability ◽  
Spatial And Temporal Variation ◽  
Spatial And Temporal Scales ◽  
The United Kingdom ◽  
The Impact ◽  
Seal Diet

Knowledge about the diet of fish-eating predators is critical when evaluating conflicts with the fishing industry. Numerous primary studies have examined the diet of grey seals Halichoerus grypus and common seals Phoca vitulina in a bid to understand the ecology of these predators. However, studies of large-scale spatial and temporal variation in seal diet are limited. Therefore this review combines the results of seal diet studies published between 1980 and 2000 to examine how seal diet varies at a range of spatial and temporal scales. Our results revealed extensive spatial variation in gadiform, perciform and flatfish consumption, likely reflecting variation in prey availability. Flatfish and gadiform consumption varied between years, reflecting changes in fish assemblages as a consequence of factors such as varying fishing pressures, climate change and natural fluctuations in populations. Perciform and gadiform consumption varied seasonally: in addition there was a significant interaction between season and seal species, indicating that grey and common seals exhibited different patterns of seasonal variation in their consumption of Perciformes and Gadiformes. Multivariate analysis of grey seal diet revealed spatial variation at a much smaller scale, with different species dominating the diet in different areas. The existence of spatial and temporal variation in seal diet emphasizes that future assessments of the impact of seal populations should not be based on past or localized estimates of diet and highlights the need for up-to-date, site specific estimates of diet composition in the context of understanding and resolving seal/fisheries conflict.

scholarly journals Spatial and temporal variation in community composition of herbivorous insects on Neoboutonia macrocalyx in a primary tropical rain forest

2013 ◽  
Vol 29 (3) ◽  
pp. 229-241 ◽  
Author(s):  
Kaisa Heimonen ◽  
Jeremiah S. Lwanga ◽  
Marko Mutanen ◽  
Tommi Nyman ◽  
Heikki Roininen
Keyword(s):  
Species Richness ◽  
Temporal Variation ◽  
Community Composition ◽  
Rain Forest ◽  
Tropical Rain Forest ◽  
Spatial And Temporal Variation ◽  
Herbivorous Insects ◽  
Herbivorous Insect ◽  
Insect Communities ◽  
Study Sites

Abstract:Spatial and temporal variation of tropical insect communities has rarely been studied, although such variation influences estimates of global species richness. Therefore, we compared spatial and temporal variation of herbivorous insect communities on Neoboutonia macrocalyx trees among seven sites over 1 y in a primary tropical rain forest in Kibale National Park, Uganda. The distance between the study sites varied from 4.8 to 31.2 km and altitudinal differences ranged from 20 to 242 m. Permutational multivariate analysis of variance (PERMANOVA) revealed significant spatial changes in community composition of the herbivorous insects and study sites differed also in insect abundance (6.9–26.2 individuals m−2 of leaf area). This is likely to be caused by differences in vegetation, altitude and microclimate among the study sites. The similarity of insect species composition was negatively correlated with geographic and altitudinal distances among sites and positively correlated with the similarity of tree community composition. Species richness varied significantly between sampling dates, ranging from 33 to 41 species. Also community compositions changed between sampling dates, which likely follows from marked seasonal changes in climate and the phenology of other host plants used by the generalist insect species also living on Neoboutonia macrocalyx. In general our study supports the idea of high variability of herbivorous insect communities in primary rain forests even at a small spatial scale. This should be considered when estimations of insect biodiversity are made.

scholarly journals Spatial and temporal variation of benthic fish assemblages during the extreme drought of 1997-98 (El Niño) in the middle rio Negro, Amazonia, Brazil

2004 ◽  
Vol 2 (3) ◽  
pp. 127-136 ◽  
Author(s):  
Mario J. F. Thomé-Souza ◽  
Ning Labbish Chao
Keyword(s):  
Species Richness ◽  
Temporal Variation ◽  
Fish Assemblages ◽  
Dry Season ◽  
Spatial And Temporal Variation ◽  
Otter Trawl ◽  
Total Biomass ◽  
Benthic Fish ◽  
Rio Negro ◽  
Density And Biomass

Spatial and temporal variation in the benthic fish composition, species richness, density and biomass were studied in the lower rio Branco and its confluence with the rio Negro during the 1997-98 dry season (September to February). Samples were taken with a 5.28 m (16-ft) otter trawl in three expeditions and at two depth strata (<7m and >7m). Five to seven trawl hauls were made randomly in each sample site per expedition. A total of 58 trawls yielded 134 species, 5,657 individuals and 22 kg total biomass. Fishes were distributed in 25 families and seven orders. Siluriformes was the most specious with 59 species, followed by Gymnotiformes (30), Characiformes (30), Perciformes (9), Clupeiformes (4), Pleuronectiformes (1) and Tetraodontiformes (1). The variation on composition, richness of species, density and biomass occurred during the dry season, from September 1997 to February 1998. Differences between depth strata were observed. Siluriformes and Gymnotiformes were more abundant at the beginning of the dry season (September) but diminished toward the end of dry season (February), whereas the Perciformes and Characiformes (mainly post-larvae and juveniles) became more abundant at the end of the dry season. The diminishing density of benthic fish communities during this extremely dry season may have been caused by predation or migration.

scholarly journals Spatial and Temporal Variation in Microbial Diversity and Community Structure in a Contaminated Mangrove Wetland

2020 ◽  
Vol 10 (17) ◽  
pp. 5850
Author(s):  
Jiaojiao Ma ◽  
Ting Zhou ◽  
Chunyu Xu ◽  
Dawen Shen ◽  
Songjun Xu ◽  
...  
Keyword(s):  
Community Structure ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Bacterial Diversity ◽  
Diversity Index ◽  
Total Carbon ◽  
Spatial And Temporal Variation ◽  
Rrna Gene ◽  
Mangrove Wetland ◽  
Mangrove Soils

Field and laboratory investigations were conducted to characterize bacterial diversity and community structure in a badly contaminated mangrove wetland adjacent to the metropolitan area of a megacity in subtropical China. Next-generation sequencing technique was used for sequencing the V4–V5 region of the 16s rRNA gene on the Illumina system. Collectively, Proteobacteria, Chloroflexi, Planctomycetes, Actinobacteria and Bacteroidetes were the predominant phyla identified in the investigated soils. A significant spatial variation in bacterial diversity and community structure was observed for the investigated mangrove soils. Heavy metal pollution played a key role in reducing the bacterial diversity. The spatial variation in soil-borne heavy metals shaped the spatial variation in bacterial diversity and community structure in the study area. Other environmental factors such as total carbon and total nitrogen in the soils that are affected by seasonal change in temperature could also influence the bacterial abundance, diversity and community structure though the temporal variation was relatively weaker, as compared to spatial variation. The bacterial diversity index was lower in the investigated site than in the comparable reference site with less contaminated status. The community structure in mangrove soils at the current study site was, to a remarkable extent, different from those in the tropical mangrove wetlands around the world.

scholarly journals Spatial distribution and temporal variation of microcrustaceans assembly (Cladocera and Copepoda) in different compartments of a reservoir in the brazilian semiarid region

2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Josiane Souza Santos ◽  
Nadson Ressyé Simões ◽  
Sérgio Luiz Sonoda
Keyword(s):  
Spatial Distribution ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Aquatic Macrophytes ◽  
Temporal Dynamics ◽  
Lateral Compartment ◽  
Spatial And Temporal Variation ◽  
Semiarid Region ◽  
Brazilian Semiarid ◽  
Significant Spatial Variation

Abstract Aim: The objective of this study was to investigate the spatial and temporal variation of microcrustacean assemblages of a reservoir in the Brazilian semiarid region. Methods Physical and chemical water variables and samples of microcrustaceans were collected at eight sites of the reservoir between July 2013 and November 2014, in a total of seven campaigns. For this study, the reservoir was categorized in two compartments: lateral and central. Results Limnological variables showed significant temporal variation (PERMANOVA, Pseudo-F = 19.51, p = 0.001). Higher turbidity values and suspended solids were observed in the rainiest months, while during the dry months, we measured higher values of transparency, dissolved oxygen, and chlorophyll-a. It was not found significant spatial variation of limnological variables (PERMANOVA, Pseudo-F = 0.96; p = 0.394). During the study period, ten species were recorded: four Cladocera (Ceriodaphnia cornuta, Daphnia gessneri, Diaphanosoma birgei and Diaphanosoma spinulosum ) three Copepoda Calanoida (Argyrodiaptomus azevedoi, Notodiaptomus cearensis and Notodiaptomus iheringi) and three Copepoda Cyclopoida (Macrocyclops albidus, Thermocyclops minutus and Thermocyclops decipiens). The microcrustacean assemblages showed significant temporal variation (PERMANOVA, Pseudo-F = 4.34; p = 0.001) as well as significant spatial variation (PERMANOVA, Pseudo-F = 9.46; p = 0.001). The highest values of abundance and richness were observed in the lateral compartment, this result is mainly related to the presence of aquatic macrophytes in this region, because the analysis of partial RDA indicated that limnological variables explained only 11% of this variation (Pseudo-F = 2.08, p = 0.001). Conclusions The results suggest that the seasonality of the semiarid is an important factor in the temporal dynamics of the limnological variables, while the aquatic macrophytes play an important role in the spatial distribution of the microcrustacean assembly.

Spatial variation in CO2 efflux from the soil in a mature beech forest ecosystem.

2021 ◽  
Author(s):  
Yihan Cai ◽  
Takahiro Nishimura ◽  
Hideyuki Ida ◽  
Mitsuru Hirota
Keyword(s):  
Spatial Variation ◽  
Temporal Variation ◽  
Forest Ecosystem ◽  
Linear Regression Analysis ◽  
Basal Area ◽  
Beech Forest ◽  
Controlling Factors ◽  
Spatial And Temporal Variation ◽  
Canopy Openness ◽  
Co2 Efflux

&lt;p&gt;&amp;#160;Soil respiration (Rs) is the second largest carbon flux between the atmosphere and terrestrial ecosystem. Because of the large proportion, even small change in Rs would considerably impact the global carbon cycle. Therefore, it is important to accurately estimate Rs by taking its spatial and temporal variation into consideration. While the temporal variation of Rs and its controlling factors have been well-described, large unexplainable part still has been remained in the spatial variation of Rs especially in the forest ecosystems with complex structures. The objective of this study is to fill the knowledge gap about spatial variation of Rs and its controlling factors in a typical mature beech forest in Japan. Hypotheses of this study were, 1) Rs would show large spatial variation in the mature beech forest, 2) the spatial variation of Rs was mainly influenced by soil water content (SWC) and soil temperature (ST), 3) the two key factors were determined by the forest structures. This study was conducted in a 1- ha permanent study plot in the mature beech forest with significant gap-mosaic structures. To examine these hypotheses, Rs, SWC, ST and parameters related to forest structure, i.e. sum of basal area, diameter at breast height, number of trees, number of species within a radius of 5 m from the Rs measurement points, and canopy openness were measured at 121 points in different season between 2012 to 2013. In this study, all the measurements of Rs were conducted by using alkali-absorption technique.&lt;/p&gt;&lt;p&gt;&amp;#160;Coefficient of variation of Rs was between 25 - 28 % which was similar to that of SWC in all the measurements. The spatial variation of Rs was relatively higher in July, August and September than that in June and October. There was no significant relationship in the spatial variation between Rs and ST in all the measurements, meanwhile, Rs was well explained by SWC in measurements conducted in August, September and October. Multiple linear regression analysis indicated that canopy openness and sum of basal area showed significant positive and negative correlation with SWC, respectively. And canopy openness explained SWC much more than sum of basal area did. This result suggested that SWC, the key factor determined the spatial variation of Rs, cannot be only explained by stems distribution and their characteristics, but also canopy architecture in the forest ecosystem.&lt;/p&gt;

scholarly journals Aquatic macrophyte community varies in urban reservoirs with different degrees of eutrophication

2014 ◽  
Vol 26 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Suelen Cristina Alves da Silva ◽  
Armando Carlos Cervi ◽  
Cleusa Bona ◽  
André Andrian Padial
Keyword(s):  
Species Richness ◽  
Temporal Variation ◽  
Indicator Species ◽  
Beta Diversity ◽  
Aquatic Macrophytes ◽  
Aquatic Macrophyte ◽  
Wiener Index ◽  
Spatial And Temporal Variation ◽  
Macrophyte Community ◽  
Aquatic Macrophyte Community

AIM: Investigate spatial and temporal variation in the aquatic macrophyte community in four urban reservoirs located in Curitiba metropolitan region, Brazil. We tested the hypothesis that aquatic macrophyte community differ among reservoirs with different degrees of eutrophication. METHODS: The reservoirs selected ranged from oligotrophic/mesotrophic to eutrophic. Sampling occurred in October 2011, January 2012 and June 2012. Twelve aquatic macrophytes stands were sampled at each reservoir. Species were identified and the relative abundance of aquatic macrophytes was estimated. Differences among reservoirs and over sampling periods were analyzed: i) through two‑way ANOVAs considering the stand extent (m) and the stand biodiversity - species richness, evenness, Shannon-Wiener index and beta diversity (species variation along the aquatic macrophyte stand); and ii) through PERMANOVA considering species composition. Indicator species that were characteristic for each reservoir were also identified. RESULTS: The aquatic macrophyte stand extent varied among reservoirs and over sampling periods. Species richness showed only temporal variation. On the other hand, evenness and Shannon-Wiener index varied only among reservoirs. The beta diversity of macrophyte stands did not vary among reservoirs or over time, meaning that species variability among aquatic macrophyte stands was independent of the stand extent and reservoir eutrophication. Community composition depended on the reservoir and sampling period. CONCLUSIONS: Our results support our initial expectation that reservoirs of different degrees of eutrophication have different aquatic macrophyte communities. As a consequence, each reservoir had particular indicator species. Therefore, monitoring and management efforts must be offered for each reservoir individually.

Spatial and temporal variation in assemblages of Lutjanidae, Lethrinidae and associated fish species among mid-continental shelf reefs in the central Great Barrier Reef

2001 ◽  
Vol 52 (6) ◽  
pp. 843 ◽  
Author(s):  
Stephen J. Newman ◽  
David McB. Williams
Keyword(s):  
Continental Shelf ◽  
Temporal Variation ◽  
Fish Assemblages ◽  
Spatial And Temporal Variation ◽  
Shallow Trap ◽  
Fish Traps ◽  
Lutjanus Carponotatus ◽  
Plectropomus Leopardus ◽  
Trap Catches ◽  
Over Time

Visual censuses were used to survey shallow-water assemblages of the Lutjanidae and Lethrinidae among three mid-continental shelf reefs, and fish traps were used to survey deeper water assemblages below diveable depths. Significant differences were found in visual censuses of the Lutjanidae and Lethrinidae among reefs. Trap catches of the Lutjanidae and Lethrinidae varied more between depths and diel sampling periods than among reefs or over time. Lutjanus carponotatus, L. fulviflamma and Lethrinus miniatus were more abundant in shallow trap sets, whereas Lutjanus adetii, L. russelli, L. sebae, L. vitta, Gymnocranius audleyi, Lethrinus sp.2 and Abalistes stellaris were more abundant in deeper sets. Additionally, Lutjanus adetii, L. fulviflamma, L. quinquelineatus, L. russelli, L. sebae, L. vitta and Lethrinus miniatus were more abundant at night, whereas Lethrinus sp. 2, Abalistes stellarisand Plectropomus leopardus were more abundant during the day. The absence of significant temporal variation in the observed spatial patterns both among reefs and between depths indicates that these patterns may persist through time. The use of both visual censuses and fish traps to assess reef fish assemblages may provide an objective way of repeatedly censusing reefs for monitoring purposes, especially where differences among reefs and regions are important.

scholarly journals Spatial and temporal variation in fish assemblages in three small unpolluted estuarine rivers and associated lagoons in Kouchibouguac National Park, southern Gulf of St. Lawrence, Canada

2015 ◽  
Vol 129 (2) ◽  
pp. 121 ◽  
Author(s):  
Amanda M. Bremner ◽  
D. A. Methven ◽  
Kelly R. Munkittrick ◽  
Katherine A. Frego
Keyword(s):  
Water Temperature ◽  
Dominant Species ◽  
Gasterosteus Aculeatus ◽  
Fish Assemblages ◽  
Vegetation Coverage ◽  
Spatial And Temporal Variation ◽  
Fish Diversity ◽  
Spatial Gradient ◽  
Scaling Analysis ◽  
Pungitius Pungitius

Estuaries have among the highest primary production rates of ocean waters and provide essential habitat for many organisms. Recognition of the need to conserve these critical habitats is coupled with the need for baseline data to allow assessment of ecosystem changes. This study compares natural variations in, and correlations between, the composition of fish assemblages and environmental factors at several sites over two years in three rivers emptying into estuaries in the southern Gulf of St. Lawrence, Canada. Fish diversity and abundance were determined by beach seining and related to water temperature, salinity, substrate, and vegetation. From May to September 2000 (14 sites) and May to August 2001 (15 sites), 20 fish species were collected, seven of which accounted for 98% of the total catch. The dominant species, Mummichog (Fundulus heteroclitus), represented 44% of the catch. Its abundance and that of the other dominant species — Threespine Stickleback (Gasterosteus aculeatus) 16%, Blackspotted Stickleback (G. wheatlandi) 13%, Banded Killifish (F. diaphanus) 12%, Fourspine Stickleback (Apeltes quadracus) 7%, Atlantic Silverside (Menidia menidia) 4%, and Ninespine Stickleback (Pungitius pungitius) 2% — differed significantly both spatially and temporally. Multidimensional scaling analysis showed a spatial gradient in abundance from upstream to lagoon sites and a temporal gradient from spring to fall. Upstream sites were low in salinity and had a higher organic content and a higher proportion of silt–clay in the sediment. Variation within fish populations was related to site and seasonal changes in environmental conditions and species’ tolerance of water temperature, salinity, vegetation coverage, and fine sediments.

scholarly journals What drives the spatial distribution and dynamics of local species richness in tropical forest?

2017 ◽  
Vol 284 (1863) ◽  
pp. 20171503 ◽  
Author(s):  
Thorsten Wiegand ◽  
Felix May ◽  
Martin Kazmierczak ◽  
Andreas Huth
Keyword(s):  
Species Richness ◽  
Tropical Forest ◽  
Temporal Variation ◽  
Tropical Forests ◽  
Temporal Variability ◽  
Dynamic Models ◽  
Neutral Theory ◽  
Spatial And Temporal Variation ◽  
Demographic Stochasticity ◽  
Spatio Temporal

Understanding the structure and dynamics of highly diverse tropical forests is challenging. Here we investigate the factors that drive the spatio-temporal variation of local tree numbers and species richness in a tropical forest (including 1250 plots of 20 × 20 m 2 ). To this end, we use a series of dynamic models that are built around the local spatial variation of mortality and recruitment rates, and ask which combination of processes can explain the observed spatial and temporal variation in tree and species numbers. We find that processes not included in classical neutral theory are needed to explain these fundamental patterns of the observed local forest dynamics. We identified a large spatio-temporal variability in the local number of recruits as the main missing mechanism, whereas variability of mortality rates contributed to a lesser extent. We also found that local tree numbers stabilize at typical values which can be explained by a simple analytical model. Our study emphasized the importance of spatio-temporal variability in recruitment beyond demographic stochasticity for explaining the local heterogeneity of tropical forests.

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