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A Modelling Framework to Assess the Effect of Pressures on River Abiotic Habitat Conditions and Biota.

Kail J, Guse B, Radinger J, Schröder M, Kiesel J, Kleinhans M, Schuurman F, Fohrer N, Hering D, Wolter C - PLoS ONE (2015)

Bottom Line: Moreover, these approaches do not consider long-term morphological changes that affect habitat conditions.Technically, it was possible to link the different models, but future applications would benefit from the development of open source software for all modelling steps to enable fully automated model runs.The modelling framework is flexible and allows for including additional models and investigating different research and management questions, e.g., in climate impact research as well as river restoration and management.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Ecology of Fishes, Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Berlin, Germany; Department of Aquatic Ecology, University of Duisburg-Essen, Essen, Germany.

ABSTRACT
River biota are affected by global reach-scale pressures, but most approaches for predicting biota of rivers focus on river reach or segment scale processes and habitats. Moreover, these approaches do not consider long-term morphological changes that affect habitat conditions. In this study, a modelling framework was further developed and tested to assess the effect of pressures at different spatial scales on reach-scale habitat conditions and biota. Ecohydrological and 1D hydrodynamic models were used to predict discharge and water quality at the catchment scale and the resulting water level at the downstream end of a study reach. Long-term reach morphology was modelled using empirical regime equations, meander migration and 2D morphodynamic models. The respective flow and substrate conditions in the study reach were predicted using a 2D hydrodynamic model, and the suitability of these habitats was assessed with novel habitat models. In addition, dispersal models for fish and macroinvertebrates were developed to assess the re-colonization potential and to finally compare habitat suitability and the availability/ability of species to colonize these habitats. Applicability was tested and model performance was assessed by comparing observed and predicted conditions in the lowland Treene River in northern Germany. Technically, it was possible to link the different models, but future applications would benefit from the development of open source software for all modelling steps to enable fully automated model runs. Future research needs concern the physical modelling of long-term morphodynamics, feedback of biota (e.g., macrophytes) on abiotic habitat conditions, species interactions, and empirical data on the hydraulic habitat suitability and dispersal abilities of macroinvertebrates. The modelling framework is flexible and allows for including additional models and investigating different research and management questions, e.g., in climate impact research as well as river restoration and management.

No MeSH data available.


Combining results of habitat suitability and dispersal models to assess the presence of species at the reach scale.
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pone.0130228.g003: Combining results of habitat suitability and dispersal models to assess the presence of species at the reach scale.

Mentions: For the final biological assessment, the modelling results on habitat suitability and the re-colonization potential were combined in a semi-quantitative way. Species were ranked according to the habitat suitability and re-colonization potential. Based on this ranking, they can be classified as having a high or low probability of populating the study reach (high or low habitat suitability) in the short or long term (high or low re-colonization potential) (Fig 3). The re-colonization potential was assessed for the whole river network by calculating the length of the river network that is reachable after a specific modelling period, i.e., results were upscaled to assess the effect of restoring reaches in the river network to similar habitat conditions found in the near-natural study reach. The re-colonization potential was standardized by dividing the length of the reachable river network by the total river network length, resulting in a dimensionless value (share or percentage). Similarly, values for habitat suitability were standardized. For fish, the Weighted Usable Area (WUA) was standardized by calculating its share on the bankfull wetted area, which can be considered the maximum possible value (100%). In addition to using the median WUA value of all 12 months, the range of the 12 values was calculated, with the minimum monthly value potentially acting as a bottleneck. For macroinvertebrates, the abundance predicted by the Habitat Evaluation Tool (HET) for the present substrate and nutrient conditions was standardized using the abundance predicted for the natural substrate conditions described in Pottgiesser and Sommerhäuser [46], which can be considered the maximum or best possible value (100%). Because the coverage of different substrates varies in natural rivers, ranges were used (e.g., 5–20% gravel), resulting in a range of natural reference conditions and, hence, a range of relative abundance values for the present state.


A Modelling Framework to Assess the Effect of Pressures on River Abiotic Habitat Conditions and Biota.

Kail J, Guse B, Radinger J, Schröder M, Kiesel J, Kleinhans M, Schuurman F, Fohrer N, Hering D, Wolter C - PLoS ONE (2015)

Combining results of habitat suitability and dispersal models to assess the presence of species at the reach scale.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482704&req=5

pone.0130228.g003: Combining results of habitat suitability and dispersal models to assess the presence of species at the reach scale.
Mentions: For the final biological assessment, the modelling results on habitat suitability and the re-colonization potential were combined in a semi-quantitative way. Species were ranked according to the habitat suitability and re-colonization potential. Based on this ranking, they can be classified as having a high or low probability of populating the study reach (high or low habitat suitability) in the short or long term (high or low re-colonization potential) (Fig 3). The re-colonization potential was assessed for the whole river network by calculating the length of the river network that is reachable after a specific modelling period, i.e., results were upscaled to assess the effect of restoring reaches in the river network to similar habitat conditions found in the near-natural study reach. The re-colonization potential was standardized by dividing the length of the reachable river network by the total river network length, resulting in a dimensionless value (share or percentage). Similarly, values for habitat suitability were standardized. For fish, the Weighted Usable Area (WUA) was standardized by calculating its share on the bankfull wetted area, which can be considered the maximum possible value (100%). In addition to using the median WUA value of all 12 months, the range of the 12 values was calculated, with the minimum monthly value potentially acting as a bottleneck. For macroinvertebrates, the abundance predicted by the Habitat Evaluation Tool (HET) for the present substrate and nutrient conditions was standardized using the abundance predicted for the natural substrate conditions described in Pottgiesser and Sommerhäuser [46], which can be considered the maximum or best possible value (100%). Because the coverage of different substrates varies in natural rivers, ranges were used (e.g., 5–20% gravel), resulting in a range of natural reference conditions and, hence, a range of relative abundance values for the present state.

Bottom Line: Moreover, these approaches do not consider long-term morphological changes that affect habitat conditions.Technically, it was possible to link the different models, but future applications would benefit from the development of open source software for all modelling steps to enable fully automated model runs.The modelling framework is flexible and allows for including additional models and investigating different research and management questions, e.g., in climate impact research as well as river restoration and management.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Ecology of Fishes, Leibniz-Institute for Freshwater Ecology and Inland Fisheries, Berlin, Germany; Department of Aquatic Ecology, University of Duisburg-Essen, Essen, Germany.

ABSTRACT
River biota are affected by global reach-scale pressures, but most approaches for predicting biota of rivers focus on river reach or segment scale processes and habitats. Moreover, these approaches do not consider long-term morphological changes that affect habitat conditions. In this study, a modelling framework was further developed and tested to assess the effect of pressures at different spatial scales on reach-scale habitat conditions and biota. Ecohydrological and 1D hydrodynamic models were used to predict discharge and water quality at the catchment scale and the resulting water level at the downstream end of a study reach. Long-term reach morphology was modelled using empirical regime equations, meander migration and 2D morphodynamic models. The respective flow and substrate conditions in the study reach were predicted using a 2D hydrodynamic model, and the suitability of these habitats was assessed with novel habitat models. In addition, dispersal models for fish and macroinvertebrates were developed to assess the re-colonization potential and to finally compare habitat suitability and the availability/ability of species to colonize these habitats. Applicability was tested and model performance was assessed by comparing observed and predicted conditions in the lowland Treene River in northern Germany. Technically, it was possible to link the different models, but future applications would benefit from the development of open source software for all modelling steps to enable fully automated model runs. Future research needs concern the physical modelling of long-term morphodynamics, feedback of biota (e.g., macrophytes) on abiotic habitat conditions, species interactions, and empirical data on the hydraulic habitat suitability and dispersal abilities of macroinvertebrates. The modelling framework is flexible and allows for including additional models and investigating different research and management questions, e.g., in climate impact research as well as river restoration and management.

No MeSH data available.