Effects of sampling effort, assemblage similarity, and habitat heterogeneity on estimates of species richness and relative abundance of stream fishes

2009 ◽  
Vol 66 (2) ◽  
pp. 277-290 ◽  
Author(s):  
Jesse R. Fischer ◽  
Craig P. Paukert

We estimated the sampling effort required to accurately estimate species richness and to detect changes in catch-per-unit-effort (CPUE) in four Great Plains, USA, streams. The number of sampled reaches (i.e., <1 km) required to estimate stream-segment (i.e., 20–28 km) species richness decreased with increased sampled reach length (i.e., 10, 20, 40, or 60 mean stream widths, MSW), whereas total sampling effort decreased with a greater number of shorter sampled reaches. Collecting all species in a stream segment required all sampled reaches (i.e., 10) of a length equal to 40 or 60 MSW. The number of stream reaches sampled with lengths equal to 40 MSW required to detect a 50% change in CPUE of common species (i.e., total abundance > 1% of total catch) with β = 0.80 ranged from 7 to 630 (mean = 99) and decreased with longer sampled reaches. A greater number of sampled reaches were needed to detect 90% of species richness and 25% changes in CPUE when Jaccard’s similarity of samples of stream fish assemblages and habitat heterogeneity was lower within streams. Our results suggest that homogeneous stream segments require more sampled reaches to characterize fish assemblages and monitor trends in fish abundance.

2019 ◽  
Vol 76 (4) ◽  
pp. 1131-1139 ◽  
Author(s):  
Ben L Gilby ◽  
Andrew D Olds ◽  
Christopher J Henderson ◽  
Nicholas L Ortodossi ◽  
Rod M Connolly ◽  
...  

Abstract The seascape context of coastal ecosystems plays a pivotal role in shaping patterns in fish recruitment, abundance, and diversity. It might also be a principal determinant in structuring the recruitment of fish assemblages to restored habitats, but the trajectories of these relationships require further testing. In this study, we surveyed fish assemblages from 14 restored oyster reefs and 14 control sites in the Noosa River, Queensland, Australia, that differed in the presence or absence of seagrass within 500 m, over four periods using baited cameras. Fish assemblages at oyster reefs differed from those at control sites, with higher species richness (1.4 times) and more individuals of taxa that are harvested by fishers (1.8 times). The presence or absence of seagrass nearby affected the abundance of a key harvestable fish species (yellowfin bream Acanthopagrus australis) on oyster reefs, but not the overall composition of fish assemblages, species richness, or the total abundance of harvestable fishes overall. These findings highlight the importance of considering species-specific patterns in seascape utilization when selecting restoration sites and setting restoration goals, and suggest that the effects of restoration on fish assemblages might be optimized by focusing efforts in prime positions in coastal seascapes.


2011 ◽  
Vol 23 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Yzel Rondon Súarez ◽  
Marcelo Maldonado de Souza ◽  
Fabiane Silva Ferreira ◽  
Maiane Jardim Pereira ◽  
Ediléia Amancio da Silva ◽  
...  

AIM: The present study analyzed the spatial variation in fish species richness and composition in streams of the Ivinhema River basin, Upper Paraná basin, determining the relationship between local and regional descriptors of the fish assemblage organization; METHOD: From 2001 to 2011 we sampled 200 stream stretches, using different sampling methods. Local species richness and composition were analyzed using univariate and multivariate methods to detect patterns of variation in the fish assemblage organization; RESULTS: We identified 111 fish species in the streams, and estimated the occurrence of 117 fish species (CIα0.05 = 111 to 123) with lower species richness in headwater streams compared to the lower parts of the basin. The fish species recorded were predominantly of small size, and the mean size increased from the headwaters to the river mouth. The four most common species are widely distributed in the basin. However, 24 species are allocthonous to the Upper Paraná basin, and two species (Chaetobranchopsis australis and Apistogramma commbrae) are recorded here for the first time in the Upper Paraná basin. Altitude was the main determinant of local fish species richness and composition, and a discontinuity in assemblage organization (richness, composition, fish size) was detected at approximately 430 m a.s.l.; CONCLUSION: Streams of the Ivinhema River basin are inhabited mainly by small-sized fishes; and longitudinal variation, interacting with local characteristics, determines the fish assemblage patterns.


2014 ◽  
Vol 59 (No. 1) ◽  
pp. 35-44 ◽  
Author(s):  
Z. Valová ◽  
M. Janáč ◽  
J. Švanyga ◽  
P. Jurajda

In August 2007, the 0+ juvenile fish assemblage of the upper River Elbe was surveyed using electrofishing. Thirty-six localities were sampled along a 177 km long section between the towns of Verdek and Brand&yacute;s nad Labem (river km (RKM) 136&ndash;313). Four localities with natural riverbeds, 14 channelized stretches, nine beaches, and nine backwaters were sampled. Altogether, 4521 0+ juvenile fishes were caught, belonging to 26 species. A decrease in species richness and abundance was evident near Hradec Kr&aacute;lov&eacute;, while decreased species abundance was noted along the navigated stretch below Přelouč. The highest catch-per-unit-effort (CPUE), species richness, and Shannon index values were observed at beach habitats, the lowest in channelized habitats, and intermediate values in backwaters. Generally, rare beach habitats had significantly more rheophilic species than other habitats, while backwaters had significantly more eurytopic species and higher CPUE for limnophilic species. Backwaters and channel habitats, however, did not differ in any other 0+&nbsp;fish assemblage parameter studied. The study demonstrated the importance of beaches for fish assemblages along navigable channels. Surprisingly, however, backwaters were not confirmed as important nursery habitats.


2019 ◽  
Author(s):  
Garabet Kazanjian

Small pelagic fishes constituted half of the Mediterranean landings and a considerable portion of the Lebanese catches. In this study, the purse seine fishery was analyzed between 2006 and 2007 in two sites along the northern coast of Lebanon.Thirty-six different fish species were collected, out of which seven constituted morethan 97% of the landings. Engraulis encrasicolus, Sardinella aurita and Sardinapilchardus composed 57.7%, 20.9% and 5.6% of the abundance of catches respectively and 31.3%, 19.2%, 9.2% of its biomass. Non-indigenous species comprised 7.2% of the total abundance and 18.7 % of the landing biomass. The fishery targeted mainly the new recruits (0+), and the vast majority of the catches were fishes below their size at first maturity. Diversity and species richness were high in the warmer in the months and low in the colder ones. Temperature and salinity were positively correlated with species richness, while the chlorophyll content of seawater was positively associated with diversity. Clear temporal patterns with distinct shifts of dominance within the landings were detected throughout the year for the most common species. Engraulids dominated catches from October to March, while the rest of the year was characterized by clupeids, Boops boops, and Scomber colias. A temporal niche partitioning seems to exist in the easternmost Mediterranean pelagic waters, possibly to minimize competition.


2016 ◽  
Vol 73 (7) ◽  
pp. 1031-1046 ◽  
Author(s):  
Yong Cao ◽  
Leon Hinz ◽  
Brian Metzke ◽  
Jeffrey Stein ◽  
Ann Holtrop

To effectively conserve and restore stream ecosystems, we need to better understand the distribution and abundance of individual fish species in relation to natural environments and anthropological stressors. In this study, we modeled the abundance of 97 fish species in small wadeable streams of Illinois, USA, based on random forests regression and landscape-level environmental variables. Model R2 values for intermediately common species were higher than for common species, but highly variable among rare ones. Models for 50 species reached R2 of 0.2–0.70 and were tested with a separate set of samples and applied to unsampled wadeable reaches to show the population hotspots of each species across the state. Furthermore, we evaluated the importance of individual environmental variables to a given fish species as well as the directional responses of each species to top 10 key predictors. Climate and land use were the best predictors for most species, followed by topography, geology, and soil permeability. Spatial connection of a stream also was associated with a large number of species. These findings improved our understanding of the relationships between fish species and landscape environments. The distribution maps could guide resource management, restoration, and monitoring of stream fish assemblages.


2018 ◽  
Vol 35 ◽  
pp. 1-5 ◽  
Author(s):  
Aila Soares Ferreira ◽  
Isabel Medeiros dos Santos Rocha ◽  
Bruno Cavalcante Bellini ◽  
Alexandre Vasconcellos

The spatial distribution of abiotic resources and environmental conditions can vary at small scales within terrestrial ecosystems, influencing the composition of soil fauna. Epiedaphic springtails (Collembola) of a semiarid Caatinga ecosystem were studied to determine if factors related to vegetation structure, such as species richness, aerial biomass, litterfall, and soil characteristics (pH, granulometry and soil organic matter), influence species richness and abundance of this group. A total of 5,513 individuals were collected of 15 species distributed in 13 genera and 9 families. The most abundant species wereTemeritassp., with 2,086 (38% of the total abundance) individuals, andNeotropiellameridionalis(Arlé, 1939), with 1,911 (35% of the total abundance) individuals. None of the variables in the regression model were significantly related to Collembola species richness, but abundance was significantly related to plant species richness, aerial biomass and soil pH. Thus, even at a small spatial scale, habitat heterogeneity influences the epiedaphic Collembola in the Caatinga ecosystem, especially their abundance.


2008 ◽  
Vol 65 (2) ◽  
pp. 245-257 ◽  
Author(s):  
Henry F Wilson ◽  
Marguerite A Xenopoulos

We examined the relationship between multiple spatial scales of fish assemblage structure and land cover in streams of a northern Great Plains ecoregion. We used regional richness measurements, an index of biotic integrity (IBI), and nonmetric multidimensional scaling (NMS) ordination to characterize fish assemblages. These metrics were related to regional catchment landscape at two spatial scales (overall catchment, overall riparian) and then to a set of local subcatchments from within these catchments at three scales (overall subcatchment, overall riparian buffer, and reach). Relationships between catchment fish richness, IBI scores, and landscape predictors were strongest at the riparian scale, with the strongest single predictor being riparian forest (r2 = 0.63, P < 0.01). NMS ordination analysis showed clear similarities between fish species assemblages in agriculturally dominated catchments and assemblages found in smaller headwater streams. At the same time, forested catchments and catchments with larger areas exhibited similar fish species assemblages. Our results indicate that both local and regional stream fish assemblages are structured by broader-scale landscape characteristics, with land cover providing a better indication of overall available habitat volume than catchment area or stream order.


2006 ◽  
Vol 63 (3) ◽  
pp. 480-493 ◽  
Author(s):  
Jeffrey A Falke ◽  
Keith B Gido

The upstream effects of reservoirs on stream fish assemblages were highly localized in 3rd- through 5th-order streams in the Great Plains, USA. Streams that differed in connectivity to reservoirs were sampled at their confluences with a river or reservoir and between the confluence and the stream's origin. Sites at confluences had higher total, nonnative, and reservoir species richness than middle sites. Variability in fish assemblage structure upstream of reservoirs was influenced by catchment area, stream size, gradient, and reservoir connectivity. Confluence sites connected to reservoirs were correctly classified based on the presence of red shiners (Cyprinella lutrensis) and bluntnose minnows (Pimephales notatus) and the absence of sand shiners (Notropis stramineus); middle sites on connected streams were classified by the absence of redfin shiners (Lythrurus umbratilis). Intensive sampling across pool habitats within two streams isolated by a reservoir indicated that abundance of common reservoir species was related to pool size, turbidity, and canopy cover, but not proximity to the reservoir. These data suggest that streams connected to reservoirs can maintain diverse native fish communities with minimal invasions by reservoir-dwelling species, but a fraction of the community either has been lost or occurs at low abundance (e.g., sand shiners and redfin shiners).


Mammalia ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Corrado Battisti ◽  
Silvio Marta ◽  
Paolo Agnelli ◽  
Luca Luiselli ◽  
Fabio Stoch ◽  
...  

AbstractPeninsular effect is an anomalous gradient in plant and animal species richness from base to tip of a given peninsula. This pattern has been studied intensely on various taxonomic groups, but with scarce attention for using standardized data. Here, using presence-absence data normalized by the field effort, the peninsular effect on the species richness of some mammalian groups (Eulipotyphla [i.e. Soricomorpha + Erinaceomorpha], Rodentia, and Chiroptera) was analyzed along the Italian peninsula. Specifically, species richness at each 30′-wide latitudinal band and the normalized species richness were compared, and generalized linear models (GLM) were used to assess whether habitat diversity, altitudinal range and area of each latitudinal band were the main predictors in explaining the peninsular effects in each of the three mammalian orders. In both Rodentia and Chiroptera, species richness was better predicted by habitat heterogeneity and by the interaction term habitat heterogeneity × field effort. For Eulipotyphla, GLM models gave no significant results. Our study highlighted the importance of taking into account the sampling effort in order to proper evaluate the peninsular effects on species richness in animals.


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