Didier PONT - Profile on Academia.edu (original) (raw)
Papers by Didier PONT
Aquatic Sciences, 2015
Using historical sources from the turn of the 19th to the 20th century, we investigated the long-... more Using historical sources from the turn of the 19th to the 20th century, we investigated the long-term evolution of the fish community in a mountainous river network and the influence of different human uses and management measures. Within the alpine Salzach catchment, historical presence was reconstructed for 26 fish species, abundance classes for 19 species. Due to channelization, flood protection and dam erections, the spatial distribution of fish species was reduced during the 20th century. Many rheophilic and eurytopic fish species historically inhabited river reaches along a wide longitudinal profile and were present in more upstream river reaches than nowadays. The decrease of species diversity in the headwater sections is a consequence of lost lateral connectivity. Strongest effects are reported for sensitive species requiring different habitat types during their life cycles (especially pike, nase, Danube salmon). One of the most important shifts from the historical fish community to the present one reflects the deliberate introduction of fish species for fisheries. Rainbow trout and brook trout, absent from the historical fish assemblage, today represent up to 29 % of the total number of fish occurrences. In contrast, log driving, one of the most common historical pressures in European mountainous rivers, did not show significant negative effects on the past fish ecological situation. This result strongly differs from the impacts of log driving and deforestation demonstrated for recent times, and could be related to the change in log driving practices during the 20th century and to the high societal value of fish before the industrialization period along with other historical pressures affecting fish in rivers without log driving. In general, our results can be valid for a large number of European mountainous rivers. They highlight the usefulness of such detailed historical studies for our understanding of the long-term evolution of fish communities and their present functioning, and point the way for future river management strategies to restore fish biodiversity.
Aquatic Sciences, 2015
Species distributions models (SDM) that rely on estimated relationships between present environme... more Species distributions models (SDM) that rely on estimated relationships between present environmental conditions and species presence-absence are widely used to forecast changes of species distributions caused by global warming but far less to reconstruct historical assemblages. By compiling historical fish data from the turn to the middle of the twentieth century in a similar way for several European catchments (Rhône, Danube), and using already published SDMs based on current observations, we: (1) tested the predictive accuracy of such models for past climatic conditions, (2) compared observed and expected cumulated historical species occurrences at sub-catchment level, and (3) compared the annual variability in the predictions within one sub-catchment (Salzach) under a future climate scenario to the long-term variability of occurrences reconstructed during an extended historical period . We finally discuss the potential of these SDMs to define a ''reference condition'', the possibility of a shift in baseline condition in relation with anthropogenic pressures, and past and future climate variability. The results of this study clearly highlight the potential of SDM to reconstruct the past composition of European fish assemblages and to analyze the historical ecological status of European rivers. Assessing the uncertainty associated with species distribution projections is of primary importance before evaluating and comparing the past and future distribution of species within a given catchment.
Conceptual framework and interdisciplinary approach for the sustainable management of gravel-bed rivers: The case of the Drôme River basin (S.E. France)
... Didier Pont1,*, HervØ PiØgay2, Aude Farinetti3, Sophie Allain4, Norbert Landon2, FrØdØric LiØ... more ... Didier Pont1,*, HervØ PiØgay2, Aude Farinetti3, Sophie Allain4, Norbert Landon2, FrØdØric LiØbault5, Bernard Dumont6 and Alexandra Richard-Mazet7 ... F-13182 Aix en Provence, France 7 Ecole VØtØrinaire de Lyon, UMR 1233 INRA - ENVL - ISARA, F-69280 Marcy l Etoile ...
A Predictive Index of Biotic Integrity Model for Aquatic-Vertebrate Assemblages of Western U.S. Streams
Transactions of the American Fisheries Society, 2009
... Journal of Applied Statistics 23:311332. Daniels, RA, K. Riva-Murray, DB Halliwell, DL Vana-... more ... Journal of Applied Statistics 23:311332. Daniels, RA, K. Riva-Murray, DB Halliwell, DL Vana-Miller, and MD Bilger. 2002. An index of biological integrity for northern Mid-Atlantic Slope drainages. ... Lewis Publishers. Chelsea, Michigan. Hughes, RM and JR Gammon. 1987. ...
Science of The Total Environment, 2010
The NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in th... more The NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.
Marine Pollution Bulletin, 2008
The concentrations of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) were moni... more The concentrations of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) were monitored in waters of the Rhône River (France) every fortnight for a full calendar year, from June 1994 to May 1995. All flood events occurring over the course of the experiment were sampled at higher frequency to better quantify the impact of these extreme hydrological episodes on the annual export of PAHs to the Mediterranean Sea. This time-series indicates that more than 90% of the annual load of particulate PAHs is transported during flood episodes, with 77% discharged during the course of only one extreme flood event occurring in November 1994. During these intense events, riverine particles are depleted in PAHs while at low river discharge particles are PAH-enriched. Dissolved PAHs were less variable and less abundant than adsorbed PAHs, consistently with the low solubility of these compounds.
Characterization of the Ebre and Rhone estuaries: A basis for defining and classifying salt-wedge estuaries
Limnology and Oceanography, 1997
... 4. Contour plot of salinity in the Ebre estuary obtained from a survey carried out on 13 Marc... more ... 4. Contour plot of salinity in the Ebre estuary obtained from a survey carried out on 13 March 1989. charge in the Ebre River in 1989 and 1990 was the lowest in recorded history (ie 129 and 118 m3 s_1, Confed. Hidrogr. del Ebro 1990). ...
Journal of the North American Benthological Society, 2010
We tested whether the functional structures of Mediterranean and temperate western European fish ... more We tested whether the functional structures of Mediterranean and temperate western European fish communities responded similarly along environmental gradients. The species pools of the 2 regions were quite different, with few species common to both regions. Each species was assigned to 1 trait for each of 6 guilds considered. We aggregated occurrences or densities of the species sharing the same traits and then computed 26 metrics describing the functional structure of fish assemblages. For each metric, we fitted and then compared 3 nested models. The 1 st model related the metric to environmental variables without taking into account the region. Therefore, the response was assumed to be the same between regions. The 2 nd model related the metric to the environmental variables with the region as an additive parameter. Therefore, the response was assumed to be similar between regions but with a constant deviation between them. The 3 rd model took into account all interactions between the environmental variables and region. Therefore, the response to the environmental gradient was assumed to be different in the 2 regions. For the 17 metrics finally tested, 11 metrics responded similarly to environmental gradients but generally showed a constant deviation between the 2 regions, and responses of 6 metrics differed between the regions. Our results highlight the roles played by biogeographical factors and the environment on current community structure in 2 neighboring but ecologically distinct regions.
Journal of Coastal Research, 2005
BEAUDOUIN, C.; SUC, J-P.; CAMBON, G.; TOUZANI, A.; GIRESSE, P.; PONT, D.; ALOISI, C.; MARSSET, T.... more BEAUDOUIN, C.; SUC, J-P.; CAMBON, G.; TOUZANI, A.; GIRESSE, P.; PONT, D.; ALOISI, C.; MARSSET, T.; COCHONAT, P.; DUZER, D., and FERRIER, J., 2005. Present-day rhythmic deposition in the grand Rhone prodelta (NW Mediterranean) according to high-resolution pollen analyses. Journal of Coastal Research, 21(2), 292-306. West Palm Beach (Florida), ISSN 0749-0208.
Sensitivity analysis of environmental changes associated with riverscape evolutions following sediment reintroduction: geomatic approach on the Drôme River network, France
International Journal of River Basin Management, 2013
ABSTRACT The present contribution aims to put into practice the conceptual framework defined in P... more ABSTRACT The present contribution aims to put into practice the conceptual framework defined in Pont et al. (2009) to the Drôme River Basin (France) in order to test the capacity of functional reach concept to be used to assess risks in environmental changes. The methodology is illustrated by examples focusing on the potential changes in functional reach diversity as a proxy of habitat diversity, and on potential impact on trout distribution at a network scale due to actions of sediment reintroduction. We used remote sensing and GIS methods to provide original data and to analyze them. A cluster analysis performed on the components of a PCA has been done to establish a functional reach typology based on planform parameters, used as a proxy of habitat typology following a review of literature. We calculated for the entire channel network an index of present and 1948 states of the functional reach types diversity to highlight past evolution. Various options of changes in functional reach types diversity were compared in relation to various increases in bedload delivery following planned deforestation. A similar risk assessment procedure is proposed in relation to changes in canopy cover and associated changes in summer temperature to evaluate impacts on brown trout distribution. Two practical examples are used as pilots for evaluating the risk assessment approach based on functional reach typology and its potential applicability for testing management actions for improving aquatic ecology. Limitations and improvements are then discussed.
Hydrobiologia, 2013
Food-chain length (FCL) is commonly used in ecological investigations to gain insight into how ec... more Food-chain length (FCL) is commonly used in ecological investigations to gain insight into how ecosystems function. Several studies have investigated the mechanisms underlying FCL patterns, but none has specifically examined the effect of temperature variability. In river ecosystems, water temperature variability can modify community structure, individuals' activity, and individuals' physiological rates, among other things. As such, we expected that it would negatively influence FCL. To test this prediction, we took advantage of a dataset comprising five streams, which mainly differ according to their temperature variability. At each stream, we (i) studied the species composition of macroinvertebrates and fish, and using nitrogen and carbon stable isotopes, (ii) estimated realized FCL, and (iii) examined food web structure.
Hydrobiologia, 1990
A four-year study showed a clear seasonal succession of species within the cladoceran community o... more A four-year study showed a clear seasonal succession of species within the cladoceran community of the large, oligotrophic Sainte-Croix reservoir (SE. France). Diaphanosoma brachyuntm and Ceriodaphnia pulchella were strictly limited to the warm stratified period (July to October), whereas Bosmina longirostris and Bosmina coregoni were dominant during spring and autumn. Daphnia longispina was the only species to occur throughout the year with higher densities in spring.
Hydrobiologia, 2013
The reference condition approach, advocated by the Water Framework Directive, is the basis of mos... more The reference condition approach, advocated by the Water Framework Directive, is the basis of most currently used multimetric indices using functional traits of fish species. The ecological status of streams is assessed by measuring the deviation of the observed trait values from the theoretical values of reference conditions in the absence of anthropogenic disturbances. While reference conditions serve as baselines for ecological assessment, they vary with natural environmental conditions. Therefore, global warming appears to be a major threat to the use of current indices for diagnosing future stream conditions, as climate change is projected to modify assemblage composition, suggesting that the functional structure of fish assemblages will also be affected. The main objectives of this study are to assess the potential effect of climate change on the trait composition of fish assemblages and the consequences for the establishment of reference conditions. The results highlight the relation between environmental, especially climatic, conditions and functional traits and project the effects of climate change on trait composition. Traits based on species intolerance are expected to be most negatively affected by the projected climatic shift. The consequences for the development of multimetric indices based on fish functional traits are discussed.
Global Ecology and Biogeography, 2006
Aim To analyse the patterns in species richness and endemism of the native European riverine fish... more Aim To analyse the patterns in species richness and endemism of the native European riverine fish fauna, in the light of the Messinian salinity crisis and the Last Glacial Maximum (LGM).
Global Ecology and Biogeography, 2007
Aim To analyse the patterns in species richness and endemism of the native European riverine fish... more Aim To analyse the patterns in species richness and endemism of the native European riverine fish fauna, in the light of the Messinian salinity crisis and the Last Glacial Maximum (LGM).
Development and validation of a fish-based index for the assessment of 'river health' in France
Freshwater Biology, 2002
Freshwater Biology, 2001
1. Management of running waters and assessment of water quality trends require the use of biologi... more 1. Management of running waters and assessment of water quality trends require the use of biological methods. Among potential indicators, fish assemblages are of particular interest because of their ability to integrate environmental variability at different spatial scales. 2. The French Water Agencies and the Ministry of the Environment initiated a research programme to develop a fish-based index that would be applicable nation-wide. Such an index should encompass the relative importance of geographic, ecoregional and local factors influencing the distribution of riverine fishes.
Aquatic Sciences, 2015
Using historical sources from the turn of the 19th to the 20th century, we investigated the long-... more Using historical sources from the turn of the 19th to the 20th century, we investigated the long-term evolution of the fish community in a mountainous river network and the influence of different human uses and management measures. Within the alpine Salzach catchment, historical presence was reconstructed for 26 fish species, abundance classes for 19 species. Due to channelization, flood protection and dam erections, the spatial distribution of fish species was reduced during the 20th century. Many rheophilic and eurytopic fish species historically inhabited river reaches along a wide longitudinal profile and were present in more upstream river reaches than nowadays. The decrease of species diversity in the headwater sections is a consequence of lost lateral connectivity. Strongest effects are reported for sensitive species requiring different habitat types during their life cycles (especially pike, nase, Danube salmon). One of the most important shifts from the historical fish community to the present one reflects the deliberate introduction of fish species for fisheries. Rainbow trout and brook trout, absent from the historical fish assemblage, today represent up to 29 % of the total number of fish occurrences. In contrast, log driving, one of the most common historical pressures in European mountainous rivers, did not show significant negative effects on the past fish ecological situation. This result strongly differs from the impacts of log driving and deforestation demonstrated for recent times, and could be related to the change in log driving practices during the 20th century and to the high societal value of fish before the industrialization period along with other historical pressures affecting fish in rivers without log driving. In general, our results can be valid for a large number of European mountainous rivers. They highlight the usefulness of such detailed historical studies for our understanding of the long-term evolution of fish communities and their present functioning, and point the way for future river management strategies to restore fish biodiversity.
Aquatic Sciences, 2015
Species distributions models (SDM) that rely on estimated relationships between present environme... more Species distributions models (SDM) that rely on estimated relationships between present environmental conditions and species presence-absence are widely used to forecast changes of species distributions caused by global warming but far less to reconstruct historical assemblages. By compiling historical fish data from the turn to the middle of the twentieth century in a similar way for several European catchments (Rhône, Danube), and using already published SDMs based on current observations, we: (1) tested the predictive accuracy of such models for past climatic conditions, (2) compared observed and expected cumulated historical species occurrences at sub-catchment level, and (3) compared the annual variability in the predictions within one sub-catchment (Salzach) under a future climate scenario to the long-term variability of occurrences reconstructed during an extended historical period . We finally discuss the potential of these SDMs to define a ''reference condition'', the possibility of a shift in baseline condition in relation with anthropogenic pressures, and past and future climate variability. The results of this study clearly highlight the potential of SDM to reconstruct the past composition of European fish assemblages and to analyze the historical ecological status of European rivers. Assessing the uncertainty associated with species distribution projections is of primary importance before evaluating and comparing the past and future distribution of species within a given catchment.
Conceptual framework and interdisciplinary approach for the sustainable management of gravel-bed rivers: The case of the Drôme River basin (S.E. France)
... Didier Pont1,*, HervØ PiØgay2, Aude Farinetti3, Sophie Allain4, Norbert Landon2, FrØdØric LiØ... more ... Didier Pont1,*, HervØ PiØgay2, Aude Farinetti3, Sophie Allain4, Norbert Landon2, FrØdØric LiØbault5, Bernard Dumont6 and Alexandra Richard-Mazet7 ... F-13182 Aix en Provence, France 7 Ecole VØtØrinaire de Lyon, UMR 1233 INRA - ENVL - ISARA, F-69280 Marcy l Etoile ...
A Predictive Index of Biotic Integrity Model for Aquatic-Vertebrate Assemblages of Western U.S. Streams
Transactions of the American Fisheries Society, 2009
... Journal of Applied Statistics 23:311332. Daniels, RA, K. Riva-Murray, DB Halliwell, DL Vana-... more ... Journal of Applied Statistics 23:311332. Daniels, RA, K. Riva-Murray, DB Halliwell, DL Vana-Miller, and MD Bilger. 2002. An index of biological integrity for northern Mid-Atlantic Slope drainages. ... Lewis Publishers. Chelsea, Michigan. Hughes, RM and JR Gammon. 1987. ...
Science of The Total Environment, 2010
The NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in th... more The NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.
Marine Pollution Bulletin, 2008
The concentrations of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) were moni... more The concentrations of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) were monitored in waters of the Rhône River (France) every fortnight for a full calendar year, from June 1994 to May 1995. All flood events occurring over the course of the experiment were sampled at higher frequency to better quantify the impact of these extreme hydrological episodes on the annual export of PAHs to the Mediterranean Sea. This time-series indicates that more than 90% of the annual load of particulate PAHs is transported during flood episodes, with 77% discharged during the course of only one extreme flood event occurring in November 1994. During these intense events, riverine particles are depleted in PAHs while at low river discharge particles are PAH-enriched. Dissolved PAHs were less variable and less abundant than adsorbed PAHs, consistently with the low solubility of these compounds.
Characterization of the Ebre and Rhone estuaries: A basis for defining and classifying salt-wedge estuaries
Limnology and Oceanography, 1997
... 4. Contour plot of salinity in the Ebre estuary obtained from a survey carried out on 13 Marc... more ... 4. Contour plot of salinity in the Ebre estuary obtained from a survey carried out on 13 March 1989. charge in the Ebre River in 1989 and 1990 was the lowest in recorded history (ie 129 and 118 m3 s_1, Confed. Hidrogr. del Ebro 1990). ...
Journal of the North American Benthological Society, 2010
We tested whether the functional structures of Mediterranean and temperate western European fish ... more We tested whether the functional structures of Mediterranean and temperate western European fish communities responded similarly along environmental gradients. The species pools of the 2 regions were quite different, with few species common to both regions. Each species was assigned to 1 trait for each of 6 guilds considered. We aggregated occurrences or densities of the species sharing the same traits and then computed 26 metrics describing the functional structure of fish assemblages. For each metric, we fitted and then compared 3 nested models. The 1 st model related the metric to environmental variables without taking into account the region. Therefore, the response was assumed to be the same between regions. The 2 nd model related the metric to the environmental variables with the region as an additive parameter. Therefore, the response was assumed to be similar between regions but with a constant deviation between them. The 3 rd model took into account all interactions between the environmental variables and region. Therefore, the response to the environmental gradient was assumed to be different in the 2 regions. For the 17 metrics finally tested, 11 metrics responded similarly to environmental gradients but generally showed a constant deviation between the 2 regions, and responses of 6 metrics differed between the regions. Our results highlight the roles played by biogeographical factors and the environment on current community structure in 2 neighboring but ecologically distinct regions.
Journal of Coastal Research, 2005
BEAUDOUIN, C.; SUC, J-P.; CAMBON, G.; TOUZANI, A.; GIRESSE, P.; PONT, D.; ALOISI, C.; MARSSET, T.... more BEAUDOUIN, C.; SUC, J-P.; CAMBON, G.; TOUZANI, A.; GIRESSE, P.; PONT, D.; ALOISI, C.; MARSSET, T.; COCHONAT, P.; DUZER, D., and FERRIER, J., 2005. Present-day rhythmic deposition in the grand Rhone prodelta (NW Mediterranean) according to high-resolution pollen analyses. Journal of Coastal Research, 21(2), 292-306. West Palm Beach (Florida), ISSN 0749-0208.
Sensitivity analysis of environmental changes associated with riverscape evolutions following sediment reintroduction: geomatic approach on the Drôme River network, France
International Journal of River Basin Management, 2013
ABSTRACT The present contribution aims to put into practice the conceptual framework defined in P... more ABSTRACT The present contribution aims to put into practice the conceptual framework defined in Pont et al. (2009) to the Drôme River Basin (France) in order to test the capacity of functional reach concept to be used to assess risks in environmental changes. The methodology is illustrated by examples focusing on the potential changes in functional reach diversity as a proxy of habitat diversity, and on potential impact on trout distribution at a network scale due to actions of sediment reintroduction. We used remote sensing and GIS methods to provide original data and to analyze them. A cluster analysis performed on the components of a PCA has been done to establish a functional reach typology based on planform parameters, used as a proxy of habitat typology following a review of literature. We calculated for the entire channel network an index of present and 1948 states of the functional reach types diversity to highlight past evolution. Various options of changes in functional reach types diversity were compared in relation to various increases in bedload delivery following planned deforestation. A similar risk assessment procedure is proposed in relation to changes in canopy cover and associated changes in summer temperature to evaluate impacts on brown trout distribution. Two practical examples are used as pilots for evaluating the risk assessment approach based on functional reach typology and its potential applicability for testing management actions for improving aquatic ecology. Limitations and improvements are then discussed.
Hydrobiologia, 2013
Food-chain length (FCL) is commonly used in ecological investigations to gain insight into how ec... more Food-chain length (FCL) is commonly used in ecological investigations to gain insight into how ecosystems function. Several studies have investigated the mechanisms underlying FCL patterns, but none has specifically examined the effect of temperature variability. In river ecosystems, water temperature variability can modify community structure, individuals' activity, and individuals' physiological rates, among other things. As such, we expected that it would negatively influence FCL. To test this prediction, we took advantage of a dataset comprising five streams, which mainly differ according to their temperature variability. At each stream, we (i) studied the species composition of macroinvertebrates and fish, and using nitrogen and carbon stable isotopes, (ii) estimated realized FCL, and (iii) examined food web structure.
Hydrobiologia, 1990
A four-year study showed a clear seasonal succession of species within the cladoceran community o... more A four-year study showed a clear seasonal succession of species within the cladoceran community of the large, oligotrophic Sainte-Croix reservoir (SE. France). Diaphanosoma brachyuntm and Ceriodaphnia pulchella were strictly limited to the warm stratified period (July to October), whereas Bosmina longirostris and Bosmina coregoni were dominant during spring and autumn. Daphnia longispina was the only species to occur throughout the year with higher densities in spring.
Hydrobiologia, 2013
The reference condition approach, advocated by the Water Framework Directive, is the basis of mos... more The reference condition approach, advocated by the Water Framework Directive, is the basis of most currently used multimetric indices using functional traits of fish species. The ecological status of streams is assessed by measuring the deviation of the observed trait values from the theoretical values of reference conditions in the absence of anthropogenic disturbances. While reference conditions serve as baselines for ecological assessment, they vary with natural environmental conditions. Therefore, global warming appears to be a major threat to the use of current indices for diagnosing future stream conditions, as climate change is projected to modify assemblage composition, suggesting that the functional structure of fish assemblages will also be affected. The main objectives of this study are to assess the potential effect of climate change on the trait composition of fish assemblages and the consequences for the establishment of reference conditions. The results highlight the relation between environmental, especially climatic, conditions and functional traits and project the effects of climate change on trait composition. Traits based on species intolerance are expected to be most negatively affected by the projected climatic shift. The consequences for the development of multimetric indices based on fish functional traits are discussed.
Global Ecology and Biogeography, 2006
Aim To analyse the patterns in species richness and endemism of the native European riverine fish... more Aim To analyse the patterns in species richness and endemism of the native European riverine fish fauna, in the light of the Messinian salinity crisis and the Last Glacial Maximum (LGM).
Global Ecology and Biogeography, 2007
Aim To analyse the patterns in species richness and endemism of the native European riverine fish... more Aim To analyse the patterns in species richness and endemism of the native European riverine fish fauna, in the light of the Messinian salinity crisis and the Last Glacial Maximum (LGM).
Development and validation of a fish-based index for the assessment of 'river health' in France
Freshwater Biology, 2002
Freshwater Biology, 2001
1. Management of running waters and assessment of water quality trends require the use of biologi... more 1. Management of running waters and assessment of water quality trends require the use of biological methods. Among potential indicators, fish assemblages are of particular interest because of their ability to integrate environmental variability at different spatial scales. 2. The French Water Agencies and the Ministry of the Environment initiated a research programme to develop a fish-based index that would be applicable nation-wide. Such an index should encompass the relative importance of geographic, ecoregional and local factors influencing the distribution of riverine fishes.