The Experts below are selected from a list of 83031 Experts worldwide ranked by ideXlab platform
Jack A Stanford - One of the best experts on this subject based on the ideXlab platform.
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riverine flood plains present state and future trends
Environmental Conservation, 2002Co-Authors: Klement Tockner, Jack A StanfordAbstract:SUMMARY Natural flood plains are among the most biologically productive and diverse ecosystems on earth. Globally, riverine flood plains cover � 2 � 10 6 km 2 , however, they are among the most threatened ecosystems. Floodplain degradation is closely linked to the rapid decline in freshwater biodiversity; the main reasons for the latter being habitat alteration, flow and flood control, Species Invasion and pollution. In Europe and North America, up to 90% of flood plains are already ‘cultivated’ and therefore functionally extinct. In the developing world, the remaining natural flood plains are disappearing at an accelerating rate, primarily as a result of changing hydrology. Up to the 2025 time horizon, the future increase of human population will lead to further degradation of riparian areas, intensification of the hydrological cycle, increase in the discharge of pollutants, and further proliferation of Species Invasions. In the near future, the most threat
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riverine flood plains present state and future trends
Environmental Conservation, 2002Co-Authors: Klement Tockner, Jack A StanfordAbstract:Natural flood plains are among the most biologically productive and diverse ecosystems on earth. Globally, riverine flood plains cover > 2 × 106 km2, however, they are among the most threatened ecosystems. Floodplain degradation is closely linked to the rapid decline in freshwater biodiversity; the main reasons for the latter being habitat alteration, flow and flood control, Species Invasion and pollution. In Europe and North America, up to 90% of flood plains are already ‘cultivated’ and therefore functionally extinct. In the developing world, the remaining natural flood plains are disappearing at an accelerating rate, primarily as a result of changing hydrology. Up to the 2025 time horizon, the future increase of human population will lead to further degradation of riparian areas, intensification of the hydrological cycle, increase in the discharge of pollutants, and further proliferation of Species Invasions. In the near future, the most threatened flood plains will be those in south-east Asia, Sahelian Africa and North America. There is an urgent need to preserve existing, intact flood plain rivers as strategic global resources and to begin to restore hydrologic dynamics, sediment transport and riparian vegetation to those rivers that retain some level of ecological integrity. Otherwise, dramatic extinctions of aquatic and riparian Species and of ecosystem services are faced within the next few decades.
Klement Tockner - One of the best experts on this subject based on the ideXlab platform.
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riverine flood plains present state and future trends
Environmental Conservation, 2002Co-Authors: Klement Tockner, Jack A StanfordAbstract:SUMMARY Natural flood plains are among the most biologically productive and diverse ecosystems on earth. Globally, riverine flood plains cover � 2 � 10 6 km 2 , however, they are among the most threatened ecosystems. Floodplain degradation is closely linked to the rapid decline in freshwater biodiversity; the main reasons for the latter being habitat alteration, flow and flood control, Species Invasion and pollution. In Europe and North America, up to 90% of flood plains are already ‘cultivated’ and therefore functionally extinct. In the developing world, the remaining natural flood plains are disappearing at an accelerating rate, primarily as a result of changing hydrology. Up to the 2025 time horizon, the future increase of human population will lead to further degradation of riparian areas, intensification of the hydrological cycle, increase in the discharge of pollutants, and further proliferation of Species Invasions. In the near future, the most threat
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riverine flood plains present state and future trends
Environmental Conservation, 2002Co-Authors: Klement Tockner, Jack A StanfordAbstract:Natural flood plains are among the most biologically productive and diverse ecosystems on earth. Globally, riverine flood plains cover > 2 × 106 km2, however, they are among the most threatened ecosystems. Floodplain degradation is closely linked to the rapid decline in freshwater biodiversity; the main reasons for the latter being habitat alteration, flow and flood control, Species Invasion and pollution. In Europe and North America, up to 90% of flood plains are already ‘cultivated’ and therefore functionally extinct. In the developing world, the remaining natural flood plains are disappearing at an accelerating rate, primarily as a result of changing hydrology. Up to the 2025 time horizon, the future increase of human population will lead to further degradation of riparian areas, intensification of the hydrological cycle, increase in the discharge of pollutants, and further proliferation of Species Invasions. In the near future, the most threatened flood plains will be those in south-east Asia, Sahelian Africa and North America. There is an urgent need to preserve existing, intact flood plain rivers as strategic global resources and to begin to restore hydrologic dynamics, sediment transport and riparian vegetation to those rivers that retain some level of ecological integrity. Otherwise, dramatic extinctions of aquatic and riparian Species and of ecosystem services are faced within the next few decades.
Mark A Bradford - One of the best experts on this subject based on the ideXlab platform.
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non native microstegium vimineum populations collapse with fungal leaf spot disease outbreak
Plant Ecology, 2021Co-Authors: Robert J Warren, Mark A BradfordAbstract:Non-native plants may meet little resistance in the novel range if they leave their biological enemies at home. As a result, Species Invasion can be rapid and appear unlimited. However, with time, organisms may acquire novel enemies in the novel range, or home-range enemies also may colonize the novel range. For plants, several authors have suggested that enemy release may give way to enemy acquisition in which pathogens accumulate and suppresses non-native plants. The ‘naturalization’ that occurs with acquired enemies may take decades to develop, yet most Species Invasion research lasts less than 4 years, and data tracking plant Invasion before and after the appearance of pathogens are rare. Microstegium vimineum is an Asian grass that has invaded deciduous forest habitats in the southern Midwestern and Southeastern USA and is currently expanding in the Northeastern USA. We recorded widespread expansions in M. populations in North Carolina and Georgia (USA) between 2009 and 2011 but noticed that a fungal pathogen (indicated by leaf lesions; Bipolaris sp.) appeared on several of the populations in 2011. In 2019, we re-sampled these populations to determine whether the appearance of the fungal pathogen corresponded with a suppression of M. vimineum expansion. We found the once-expanding M. vimineum populations in retreat in 2019, and the plant population contractions were greater (and seed production lesser) where the fungal leaf spot disease was most extensive. These results suggest that enemy acquisition suppressed an active non-native plant Invasion. We also found that where M. vimineum populations declined (or disappeared) native plants appeared to fill in the gap. Hence, whereby exotic Species may gain advantage in novel habitat with the loss of their native-range pathogens, with longer time spans, enemy release may give way to enemy acquisition and native populations may recover if they are immune to the pathogens.
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the interaction between propagule pressure habitat suitability and density dependent reproduction in Species Invasion
Oikos, 2012Co-Authors: Robert J Warren, Volker Bahn, Mark A BradfordAbstract:Seedling recruitment limitations create a demographic bottleneck that largely determines the viability and structure of plant populations and communities, and pose a core restriction on the colonization of novel habitat. We use a shadetolerant, invasive grass, Microstegium vimineum, to examine the interplay between seed and establishment limitations – phenomena that together determine recruitment success but usually are investigated individually. We add increasing amounts of seed to microhabitats containing variable levels of leaf litter thickness – with reduced leaf litter simulating disturbance – to investigate whether reduced seed limitation overcomes the establishment limitation posed by litter cover. We do this across gradients in understory light, moisture and temperature, and quantify germination, survival, and then per capita adult biomass and reproduction in order to understand the implications for Invasion across the landscape. We find that the combined effects of seed and establishment limitation influence recruitment; however, propagule pressure overwhelms the inhibitory effects of leaf litter thickness. Leaf litter reduces germination by 22–57% and seedling survival by 13–15% from that observed on bare soil. However, density-dependent reproduction compensates as 1–3 plants can produce far more seeds (approx. 525) than are required for persistence. As such, just a few plants may establish in understory forest habitat and subsequently overwhelm establishment barriers with copious propagule production. These results, for a widespread, invasive plant, are consistent with the emerging perspective for native plants that seed and establishment limitation jointly influence recruitment. The ability for an exotic plant Species to compensate for low population densities with high per capita seed production, that then overrides establishment limitations, makes its invasive potential daunting. Further work is required to test if this is a common mechanism underlying plant Invasions.
Peterson A. Townsend - One of the best experts on this subject based on the ideXlab platform.
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SOURCES: Predictive Invasion dynamics in American populations of the Eurasian Collared Dove Streptopelia decaocto
2017Co-Authors: Peterson A. TownsendAbstract:DATA SOURCES FOR: Species Invasions represent a significant dimension of global change, and yet the dynamics of Invasions remain poorly understood and are considered rather unpredictable. We explored year-to-year dynamics of the Invasion process in the Eurasian Collared Dove (Streptopelia decaocto), and tested whether the advance of the Species’ Invasion front in North America was related to centrality (versus peripherality) within the Species’ estimated fundamental ecological niche. Although our initial hypothesis was that the Invasion front would advance faster over more favorable (i.e., more central) conditions, in fact the reverse was the case: the Invasion expanded faster in areas presenting less favorable conditions for the Species. This result offers a first view of a predictive approach to the dynamics of Species Invasions, and thereby has important and highly relevant implications for management of many invasive Species
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Predictive Invasion dynamics in American populations of the Eurasian Collared Dove Streptopelia decaocto
2017Co-Authors: Peterson A. TownsendAbstract:R programming code for estimation of minimum volume ellipsoids from point-occurrence data in relation to environmental datasets.Species Invasions represent a significant dimension of global change, and yet the dynamics of Invasions remain poorly understood and are considered rather unpredictable. We explored year-to-year dynamics of the Invasion process in the Eurasian Collared Dove (Streptopelia decaocto), and tested whether the advance of the Species’ Invasion front in North America was related to centrality (versus peripherality) within the Species’ estimated fundamental ecological niche. Although our initial hypothesis was that the Invasion front would advance faster over more favorable (i.e., more central) conditions, in fact the reverse was the case: the Invasion expanded faster in areas presenting less favorable conditions for the Species. This result offers a first view of a predictive approach to the dynamics of Species Invasions, and thereby has important and highly relevant implications for management of many invasive Species
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DATA FOR: Predictive Invasion dynamics in American populations of the Eurasian Collared Dove Streptopelia decaocto
2017Co-Authors: Peterson A. TownsendAbstract:Occurrence data to accompany publication. Four files are contained within the zip file: calibration and testing data subsets for each of the thinned and balanced data sets.Species Invasions represent a significant dimension of global change, and yet the dynamics of Invasions remain poorly understood and are considered rather unpredictable. We explored year-to-year dynamics of the Invasion process in the Eurasian Collared Dove (Streptopelia decaocto), and tested whether the advance of the Species’ Invasion front in North America was related to centrality (versus peripherality) within the Species’ estimated fundamental ecological niche. Although our initial hypothesis was that the Invasion front would advance faster over more favorable (i.e., more central) conditions, in fact the reverse was the case: the Invasion expanded faster in areas presenting less favorable conditions for the Species. This result offers a first view of a predictive approach to the dynamics of Species Invasions, and thereby has important and highly relevant implications for management of many invasive Species
Robert J Warren - One of the best experts on this subject based on the ideXlab platform.
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non native microstegium vimineum populations collapse with fungal leaf spot disease outbreak
Plant Ecology, 2021Co-Authors: Robert J Warren, Mark A BradfordAbstract:Non-native plants may meet little resistance in the novel range if they leave their biological enemies at home. As a result, Species Invasion can be rapid and appear unlimited. However, with time, organisms may acquire novel enemies in the novel range, or home-range enemies also may colonize the novel range. For plants, several authors have suggested that enemy release may give way to enemy acquisition in which pathogens accumulate and suppresses non-native plants. The ‘naturalization’ that occurs with acquired enemies may take decades to develop, yet most Species Invasion research lasts less than 4 years, and data tracking plant Invasion before and after the appearance of pathogens are rare. Microstegium vimineum is an Asian grass that has invaded deciduous forest habitats in the southern Midwestern and Southeastern USA and is currently expanding in the Northeastern USA. We recorded widespread expansions in M. populations in North Carolina and Georgia (USA) between 2009 and 2011 but noticed that a fungal pathogen (indicated by leaf lesions; Bipolaris sp.) appeared on several of the populations in 2011. In 2019, we re-sampled these populations to determine whether the appearance of the fungal pathogen corresponded with a suppression of M. vimineum expansion. We found the once-expanding M. vimineum populations in retreat in 2019, and the plant population contractions were greater (and seed production lesser) where the fungal leaf spot disease was most extensive. These results suggest that enemy acquisition suppressed an active non-native plant Invasion. We also found that where M. vimineum populations declined (or disappeared) native plants appeared to fill in the gap. Hence, whereby exotic Species may gain advantage in novel habitat with the loss of their native-range pathogens, with longer time spans, enemy release may give way to enemy acquisition and native populations may recover if they are immune to the pathogens.
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the interaction between propagule pressure habitat suitability and density dependent reproduction in Species Invasion
Oikos, 2012Co-Authors: Robert J Warren, Volker Bahn, Mark A BradfordAbstract:Seedling recruitment limitations create a demographic bottleneck that largely determines the viability and structure of plant populations and communities, and pose a core restriction on the colonization of novel habitat. We use a shadetolerant, invasive grass, Microstegium vimineum, to examine the interplay between seed and establishment limitations – phenomena that together determine recruitment success but usually are investigated individually. We add increasing amounts of seed to microhabitats containing variable levels of leaf litter thickness – with reduced leaf litter simulating disturbance – to investigate whether reduced seed limitation overcomes the establishment limitation posed by litter cover. We do this across gradients in understory light, moisture and temperature, and quantify germination, survival, and then per capita adult biomass and reproduction in order to understand the implications for Invasion across the landscape. We find that the combined effects of seed and establishment limitation influence recruitment; however, propagule pressure overwhelms the inhibitory effects of leaf litter thickness. Leaf litter reduces germination by 22–57% and seedling survival by 13–15% from that observed on bare soil. However, density-dependent reproduction compensates as 1–3 plants can produce far more seeds (approx. 525) than are required for persistence. As such, just a few plants may establish in understory forest habitat and subsequently overwhelm establishment barriers with copious propagule production. These results, for a widespread, invasive plant, are consistent with the emerging perspective for native plants that seed and establishment limitation jointly influence recruitment. The ability for an exotic plant Species to compensate for low population densities with high per capita seed production, that then overrides establishment limitations, makes its invasive potential daunting. Further work is required to test if this is a common mechanism underlying plant Invasions.
