Fish habitat modeling: from conceptual framework to functional tools

2001 ◽  
Vol 58 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Daniel Boisclair

Natural and anthropogenic perturbations do not always equally affect all parts of an ecosystem, and all parts of an ecosystem do not equally contribute to maintain fish communities. The increasing pressure to use natural resources and to modify habitats led to the development of approaches to identify areas of key importance for fish communities. Following these approaches, aquatic systems could be perceived as puzzles, composed of a multitude of pieces with temporally flexible physical attributes and biological roles. Such a spatially explicit framework requires models that may allow one to predict fish distribution patterns and fish net energy gain once they have adopted a specific distribution pattern. Despite the conceptual appeal of spatially explicit approaches, functional tools may be obtained only after their assumptions have been tested and their models have been validated. Efforts must be deployed to identify temporal and spatial scales at which fish distribution and abundance should be estimated and modeled. Studies on fish behaviour and the energetic consequences of these behaviours must be conducted to insure that bioenergetic criteria used to define fish habitat quality do not depend on arbitrary assumptions about fish activity costs.

<em>Abstract.</em>—Longitudinal analysis of the distribution and abundance of river fishes provides a context-specific characterization of species responses to riverscape heterogeneity. We examined spatially continuous longitudinal profiles (35–70 km) of fish distribution and aquatic habitat (channel gradient, depth, temperature, and water velocity) for three northeastern Oregon rivers. We evaluated spatial patterns of river fishes and habitat using multivariate analysis to compare gradients in fish assemblage structure among rivers and at multiple spatial scales. Spatial structuring of fish assemblages exhibited a generalized pattern of cold- and coolwater fish assemblage zones but was variable within thermal zones, particularly in the warmest river. Landscape context (geographic setting and thermal condition) influenced the observed relationship between species distribution and channel gradient. To evaluate the effect of spatial extent and geographical context on observed assemblage patterns and fish–habitat relationships, we performed multiple ordinations on subsets of our data from varying lengths of each river and compared gradients in assemblage structure within and among rivers. The relative associations of water temperature increased and channel morphology decreased as the spatial scale of analysis increased. The crossover point where both variables explained equal amounts of variation was useful for identifying transitions between cool- and coldwater fish assemblages. Spatially continuous analysis of river fishes and their habitats revealed unexpected ecological patterns and provided a unique perspective on fish distribution that emphasized the importance of habitat heterogeneity and spatial variability in fish–habitat relationships.


2004 ◽  
Vol 61 (6) ◽  
pp. 954-973 ◽  
Author(s):  
Steven S Wall ◽  
Charles R Berry, Jr. ◽  
Carmen M Blausey ◽  
Jonathan A Jenks ◽  
Chad J Kopplin

Decision support tools that predict fish distribution over broad spatial scales are needed to assist in planning watershed management and endangered species recovery. We developed a geographical information system model with multivariate logistic regression to rank valley segments for probable occurrence of the endangered Topeka shiner (Notropis topeka) using stream condition variables (stream size, groundwater potential, channel slope, streamflow, network position) and land-cover variables (percent pasture, percent trees) in streams characteristic of the North American Great Plains. The stream condition and land-cover models correctly classified 89% and 68% of outcomes (i.e., presence or absence), respectively. Field tests of maps of predicted species distribution resulted in more species occurrences than expected in valley segments classified as high potential for presence and less than expected in low-potential valley segments. Gaps between high-priority segments and protected land parcels were found in all basins. In 37 basins with Topeka shiners, protected land coverage was <1% in 17 basins, 1–5% in 10 basins, and 5–21.8% in 10 basins. Conservation activities in gaps are long-term conservation measures, but maps of predicted species distribution have many immediate applications.


2009 ◽  
Vol 25 (4) ◽  
pp. 415-427 ◽  
Author(s):  
Thibaud Decaëns ◽  
Juan José Jiménez ◽  
Jean-Pierre Rossi

Abstract:Earthworm assemblages are usually spatio-temporally structured in mosaics of patches with different species composition. We re-analysed results of past research carried out in Eastern Colombia to explore how interspecific competition accounts for this pattern. In three sown pastures and three native savannas, density data matrices were obtained from spatially explicit samplings at several successive dates, and spatio-temporal patterns of species assemblages were described through partial triadic analyses and geostatistics. This first analysis detected assemblage patchiness in the six plots at spatial scales ranging from 6 to 33 m. Species richness ranged from 5 to 6 species per plot. Null models were further used to analyse niche overlap and morphometric distribution patterns at two different scales, i.e. at the ‘plot level’ and the ‘patch level’. Seasonal and vertical niche overlaps were higher than expected by chance at both scales, indicating high environmental constraints on assemblage membership. Within-patch overlaps were lower than plot-scale overlaps. Biometric niche overlap was random at the plot level and was weakly lower than that expected by chance in patches. Body weight was significantly overdispersed and constant whatever the scale, while body length and diameter showed a similar trend within patches. These results suggest that earthworms form distinct assemblages within patches, mainly driven by deterministic responses to competition: ecologically similar species avoid competition through spatial segregation, whereas a minimal level of ecological segregation is required to allow co-existence in a given patch.


2019 ◽  
Vol 76 (5) ◽  
pp. 806-814
Author(s):  
Paul W. Simonin ◽  
Lars G. Rudstam ◽  
Patrick J. Sullivan ◽  
Donna L. Parrish ◽  
Bernard Pientka

We studied the consequences of a nonnative species introduction and changes in temperature on early mortality and recruitment of native rainbow smelt (Osmerus mordax) and nonnative alewife (Alosa pseudoharengus) in Lake Champlain using a simulation model. Distribution patterns of adults and young-of-the-year (YOY) fish were predicted using a model based on observed distribution of different age groups as a function of temperature and light profiles simulated on a daily basis. Mortality rates averaged over the growing season were calculated as a function of fish densities and overlap between adults and YOY. Survival of YOY rainbow smelt and alewife depended on which predator was most abundant. Rainbow smelt YOY mortality rates are highest when rainbow smelt adults are abundant, and alewife YOY mortality rates are highest when alewife adults are abundant, potentially allowing coexistence. August and September mortality rates were higher in the climate change scenario because of increased overlap of adults and YOY of both species. These results indicate that accounting for spatiotemporal fish distribution patterns can be important when forecasting the interacting effects of climate change and aquatic invasive species on fish recruitment.


2008 ◽  
Vol 8 (4) ◽  
pp. 33-42 ◽  
Author(s):  
Mário Sérgio Sigrist ◽  
Claudio José Barros de Carvalho

An important biological challenge today is the conservation of biodiversity. Biogeography, the study of the distribution patterns of organisms, is an important tool for this challenge. Endemism, the co-occurrence of several species unique to the same area, has important implications for the preservation of biodiversity, since many areas of endemism are also areas with large human impact. More rigorously defined, areas of endemism are historical units of distributional congruence of monophyletic taxa. These areas often assumed to be due to nonrandom historical events that favored conditions associated with high rates of speciation. Thus, understanding endemism and the delimitation of endemic areas has important implications for conservation. Today, most studies delimit areas of endemism by superimposing maps of distribution for various species. This approach suffers from arbitrary delimitations, however, when a great distributional data is used. In this paper we used the method of Parsimony Analysis of Endemicity (PAE) based on georeferenced quadrats in order to delimit areas of endemism. This modality of the method is important due to its testable nature and can also be used to infer area relationships. We applied the method to raw distributional data from 19 unrelated taxa to delimit general patterns of endemism in the Neotropical Region and in the Atlantic forest domain using different grid scales. Neotropical areas found are comprised over the Panama region, northern Andean region and the Atlantic forest. Atlantic forest showed a major division into two distinct components (northern x southern). Endemic areas delimited using smaller scale grids on the Atlantic forest should be considered for conservation priorities once they showed endemism at regional and local scales. The results were also compared to other studies using different taxa and methods. Finally, some considerations on the analysis scale and future perspectives of the method are presented.


2016 ◽  
Vol 67 (5) ◽  
pp. 471-494 ◽  
Author(s):  
Matúš Hyžný

AbstractDecapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19thcentury, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global) extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic “Schlier”-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution during the Oligo-Miocene among the basins in the Paratethys. Based on the co-occurrence of certain decapod species, migration between the Paratethys and the North Sea during the Early Miocene probably occurred via the Rhine Graben. At larger spatial scales, our results suggest that the circum-Mediterranean marine decapod taxa migrated in an easterly direction during the Oligocene and/or Miocene, establishing present-day decapod communities in the Indo-West Pacific.


2013 ◽  
Vol 10 (6) ◽  
pp. 4009-4036 ◽  
Author(s):  
A. Braga-Henriques ◽  
F. M. Porteiro ◽  
P. A. Ribeiro ◽  
V. de Matos ◽  
&amp;Iacute;. Sampaio ◽  
...  

Abstract. Cold-water corals are widely considered as important structural components of benthic habitats, potentially enhancing local abundance in a variety of fish and invertebrate species. Yet, current knowledge of the taxonomic diversity and distribution patterns of these vulnerable, slow-growing organisms is scarce and fragmented, limiting the effectiveness of spatial management and conservation measures. We have conducted an exhaustive compilation of records of alcyonaceans, antipatharians, scleractinians and stylasterids available through present day to assess the diversity, distribution and spatial structure of coral assemblages in the Azores exclusive economic zone (EEZ). The resulting database comprises 2501 entries concerning historical oceanographic expeditions and other published sources, as well as unpublished data from bottom longline by-catch. Our taxonomic inventory appears to be fairly complete for the explored habitats, accounting for 164 species (79 alcyonaceans, 58 scleractinians, 18 antipatharians and 9 stylasterids), nine of which were documented for the first time. The Azores EEZ harbours a mixed coral fauna with several zoogeographic origins, showing the closest affinity with the Lusitanian–Mediterranean region. Very few apparent endemics were found (14%), and only in part supported by consistent sampling. Coral diversity is particularly high between 300 and 900 m depths, in areas recognized as traditional fishing grounds or exploitable fish habitat within the 100-mile limit of the EEZ. The composition of coral assemblages shows significant geographical structure among longitudinal sections of the study area at comparable depths (100–1500 m). There is no evidence of a possible role of the Mid-Atlantic Ridge or latitudinal effects underlying this pattern, which suggests that it may instead reflect assemblage variability among features. Stronger changes in species composition were found along the bathymetric gradient. Notwithstanding the mix of partially overlapping steno- and eurybathic species that characterize the vertical distribution of corals, there is a distinct transition from shallow (100–600 m) to intermediate (600–1000 m) depths. The analysis presented here constitutes a valuable contribution for efficient conservation policies of coral-associated vulnerable marine ecosystems and their sustainable use as fishing areas.


Author(s):  
Peeter Päll

The article looks at the geographical distribution of toponymic endings with the aim of discovering significant patterns. The corpus includes ca. 9,000 oikonyms, of which 24% are those that have the analysed endings. Endings are recognized if names have at least 3 syllables or have 2 syllables and the Q3 degree of quantity; in these cases the existence of a toponymic suffix is most likely. In the case of endings that have multiple origins there are seemingly no specific distribution patterns, with the exception of some borrowed endings (e.g. -na or -va). In the case of typical toponymic suffixes -la, -ste and -vere each of these are often concentrated into certain areas based on which the whole are of Estonia might be divided into regions: -vere-region (northern Tartumaa and northern Viljandimaa), -ste-region (Võrumaa, southern Tartumaa, southern Viljandimaa and southern Pärnumaa), -la-region (Virumaa, Järvamaa, Harjumaa) and a mixed region (Läänemaa, northern Pärnumaa). The island of Saaremaa is dominated by -la-endings, Hiiumaa is either a mixed region or a -ste-region


2021 ◽  
Author(s):  
Dandan Zhao ◽  
Tadiyose Girma Bekele ◽  
Hongxia Zhao

Abstract Benzotriazole ultraviolet stabilizers (BUVSs) have received increasing attention due to their widespread usage, ubiquitous detection and their adverse ecological effect. However, information about the bioaccumulation potential of BUVSs and their joint exposure with heavy metals remains scarce. In this study, we investigated the bioaccumulation kinetics of 6 frequently reported BUVSs in common carp under different Cu concentration for 48 d, and their tissue-specific distribution patterns (liver, kidney, gill, and muscle tissues) were also evaluated. The bioconcentration factors (BCFs) and half-lives (t1/2) in the tissues ranged from 5.73 (UV-PS) to 1076 (UV-327), and 2.19 (UV-PS) to 31.5 (UV-320) days, respectively. The tissue-specific concentration and BCF values followed the order of liver > kidney > gill > muscle with or without Cu exposure. An increase in BCF with rising Cu concentration was observed, which is caused by the decreased depuration rate (k2) in more than half of treatment groups. These results indicated that BUVSs accumulated in fish and provides important insight into the risk assessment of this group of chemicals.


2021 ◽  
Author(s):  
◽  
Benjamin Magana-Rodriguez

<p>The current crisis in loss of biodiversity requires rapid action. Knowledge of species' distribution patterns across scales is of high importance in determining their current status. However, species display many different distribution patterns on multiple scales. A positive relationship between regional (broad-scale) distribution and local abundance (fine-scale) of species is almost a constant pattern in macroecology. Nevertheless interspecific relationships typically contain much scatter. For example, species that possess high local abundance and narrow ranges, or species that are widespread, but locally rare. One way to describe these spatial features of distribution patterns is by analysing the scaling properties of occupancy (e.g., aggregation) in combination with knowledge of the processes that are generating the specific spatial pattern (e.g., reproduction, dispersal, and colonisation). The main goal of my research was to investigate if distribution patterns correlate with plant life-history traits across multiple scales. First, I compared the performance of five empirical models for their ability to describe the scaling relationship of occupancy in two datasets from Molesworth Station, New Zealand. Secondly, I analysed the association between spatial patterns and life history traits at two spatial scales in an assemblage of 46 grassland species in Molesworth Station. The spatial arrangement was quantified using the parameter k from the Negative Binomial Distribution (NBD). Finally, I investigated the same association between spatial patterns and life-history traits across local, regional and national scales, focusing in one of the most diverse families of plant species in New Zealand, the Veronica sect. Hebe (Plantaginaceae). The spatial arrangement was investigated using the mass fractal dimension. Cross-species correlations and phylogenetically independent contrasts were used to investigate the relationships between plant life-history traits and spatial patterns on both data bases. There was no superior occupancy-area model overall for describing the scaling relationship, however the results showed that a variety of occupancy-area models can be fit to different data sets at diverse spatial scales using nonlinear regression. Additionally, here I showed that it is possible to deduce and extrapolate information on occupancy at fine scales from coarse-scale data. For the 46 plantassemblage in Molesworth Station, Specific leaf area (SLA) exhibits a positive association with aggregation in cross-species analysis, while leaf area showed a negative association, and dispersule mass a positive correlation with degree of aggregation in phylogenetic contrast analysis at a local-scale (20 × 20 m resolution). Plant height was the only life-history trait that was associated with degree of aggregation at a regional-scale (100 × 60 mresolution). For the Veronica sect. Hebe dataset, leaf area showed a positive correlation with aggregation while specific leaf area showed a negative correlation with aggregation at a fine local-scale (2.5-60 m resolution). Inflorescence length, breeding system and leaf area showed a negative correlation with degree of aggregation at a regional-scale (2.5-20 km resolution). Height was positively associated with aggregation at national-scale (20-100 km resolution). Although life-history traits showed low predictive ability in explaining aggregation throughout this thesis, there was a general pattern about which processes and traits were important at different scales. At local scales traits related to dispersal and completion such as SLA , leaf area, dispersule mass and the presence of structures in seeds for dispersal, were important; while at regional scales traits related to reproduction such as breeding system, inflorescence length and traits related to dispersal (seed mass) were significant. At national scales only plant height was important in predicting aggregation. Here, it was illustrated how the parameters of these scaling models capture an important aspect of spatial pattern that can be related to other macroecological relationships and the life-history traits of species. This study shows that when several scales of analysis are considered, we can improve our understanding about the factors that are related to species' distribution patterns.</p>


Sign in / Sign up

Export Citation Format

Share Document