Pub Date : 2010-07-01DOI: 10.2174/1874213001003010041
R. C. Anderson, M. R. Anderson, J. T. Bauer, Mitchell A. Slater, J. Herold, Patrice E. Baumhardt, V. Borowicz
Garlic mustard (Alliaria petiolata), a biennial species, is considered to be among the most troublesome of the invasive plants in the Eastern Deciduous forest of North America. It has been shown to prevent or reduce mycorrhizal colonization of native herbaceous ground layer plants and trees in these forests. It is estimated that 70-90% or more of herbaceous native ground layer plant species form associations with arbuscular mycorrhizal fungi (AMF). Loss of the mycorrhizal association can reduce growth, reproductive success, and competitiveness of plant species. Using a corn root bioassay, we examined the effect of garlic mustard removal on the soil AMF mycorrhizal inoculum potential (MIP), in control plots and plots that had second-year garlic mustard removed annually for the past five years (2005-2009). Removal treatment plots had significantly (P = 0.0240, df = 28) greater MIP than control plots (25.72±2.26% and 18.29±2.04%, respectively). MIP was negatively correlated with cover of garlic mustard (r 2 = 0.1325, P < 0.05, df = 30), which accounted for 13.2% of the variation in MIP. Cover of native vegetation in removal treatment plots (104.50±2.6%) was greater than that of the control plots (95.14±3.66%), (P = 0.0236, df = 115). These results show that removal of garlic mustard results in an increase in soil MIP and cover of native species; however, there is not a complete loss of MIP associated with garlic mustard invasion. Following removal of garlic mustard, our data suggest that mycorrhizal plants recover more slowly than non-mycorrhizal species, apparently due to a delay in the establishment of a well-functioning mycorrhizal association. Our study is the first to demonstrate that the MIP of native soils and cover of native species increase following reduction in the cover of garlic mustard.
{"title":"Effect of Removal of Garlic Mustard (Alliaria petiolata, Brassicaeae) on Arbuscular Mycorrhizal Fungi Inoculum Potential in Forest Soils","authors":"R. C. Anderson, M. R. Anderson, J. T. Bauer, Mitchell A. Slater, J. Herold, Patrice E. Baumhardt, V. Borowicz","doi":"10.2174/1874213001003010041","DOIUrl":"https://doi.org/10.2174/1874213001003010041","url":null,"abstract":"Garlic mustard (Alliaria petiolata), a biennial species, is considered to be among the most troublesome of the invasive plants in the Eastern Deciduous forest of North America. It has been shown to prevent or reduce mycorrhizal colonization of native herbaceous ground layer plants and trees in these forests. It is estimated that 70-90% or more of herbaceous native ground layer plant species form associations with arbuscular mycorrhizal fungi (AMF). Loss of the mycorrhizal association can reduce growth, reproductive success, and competitiveness of plant species. Using a corn root bioassay, we examined the effect of garlic mustard removal on the soil AMF mycorrhizal inoculum potential (MIP), in control plots and plots that had second-year garlic mustard removed annually for the past five years (2005-2009). Removal treatment plots had significantly (P = 0.0240, df = 28) greater MIP than control plots (25.72±2.26% and 18.29±2.04%, respectively). MIP was negatively correlated with cover of garlic mustard (r 2 = 0.1325, P < 0.05, df = 30), which accounted for 13.2% of the variation in MIP. Cover of native vegetation in removal treatment plots (104.50±2.6%) was greater than that of the control plots (95.14±3.66%), (P = 0.0236, df = 115). These results show that removal of garlic mustard results in an increase in soil MIP and cover of native species; however, there is not a complete loss of MIP associated with garlic mustard invasion. Following removal of garlic mustard, our data suggest that mycorrhizal plants recover more slowly than non-mycorrhizal species, apparently due to a delay in the establishment of a well-functioning mycorrhizal association. Our study is the first to demonstrate that the MIP of native soils and cover of native species increase following reduction in the cover of garlic mustard.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"41-47"},"PeriodicalIF":0.0,"publicationDate":"2010-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68053751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-05-21DOI: 10.2174/1874213001003040001
M. Rodríguez-Gironés, L. Santamaría
Many flowers are visited by a large array of pollinators, often belonging to different taxonomic groups, and many pollinator species visit a wide array of flowers with different morphologies. This observation has led pollination ecologists to question the role played by pollinators in flower diversification and the extent to which floral similarities reflect convergent evolution to specific pollinator assemblages rather than other factors, such as phylogenetic constraints. In this paper, we review several ecological and evolutionary models that help to explain how pollinators can play a key role in floral evolution despite heterogeneities in plant-pollinator interactions. Our basic tenant is that, in animal pollinated species, the trajectory of pollen grains is determined by the foraging strategy of pollinators. Starting from a first approximation based on optimal foraging theory, ecological models related to the principles behind the ideal free distribution can be used to predict differences in floral and pollinator traits that will lead to resource partitioning. Building upon these results, evolutionary models based on game theory can be used to predict changes in traits of flowers and pollinators. These models show that pollinators can drive the evolution of floral divergence in the presence of behavioural noise and temporal variability in the composition of pollinator ensembles.
{"title":"How Foraging Behaviour and Resource Partitioning Can Drive the Evolution of Flowers and the Structure of Pollination Networks","authors":"M. Rodríguez-Gironés, L. Santamaría","doi":"10.2174/1874213001003040001","DOIUrl":"https://doi.org/10.2174/1874213001003040001","url":null,"abstract":"Many flowers are visited by a large array of pollinators, often belonging to different taxonomic groups, and many pollinator species visit a wide array of flowers with different morphologies. This observation has led pollination ecologists to question the role played by pollinators in flower diversification and the extent to which floral similarities reflect convergent evolution to specific pollinator assemblages rather than other factors, such as phylogenetic constraints. In this paper, we review several ecological and evolutionary models that help to explain how pollinators can play a key role in floral evolution despite heterogeneities in plant-pollinator interactions. Our basic tenant is that, in animal pollinated species, the trajectory of pollen grains is determined by the foraging strategy of pollinators. Starting from a first approximation based on optimal foraging theory, ecological models related to the principles behind the ideal free distribution can be used to predict differences in floral and pollinator traits that will lead to resource partitioning. Building upon these results, evolutionary models based on game theory can be used to predict changes in traits of flowers and pollinators. These models show that pollinators can drive the evolution of floral divergence in the presence of behavioural noise and temporal variability in the composition of pollinator ensembles.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2010-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68055153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-29DOI: 10.2174/1874213001003030008
M. M. Dunphy-Daly, M. Heithaus, Aaron J. Wirsing, J. Mardon, D. Burkholder
Exploring factors that influence diving behavior is critical to understanding energy budgets, habitat use, and exploitation rates of prey. Optimal diving behavior studies have focused primarily on trade-offs between oxygen recovery at the surface and energy intake at depth. General predictions from these models are often supported by empirical data, but a mismatch exists between theory and data that has led to increasingly complex models. Despite the importance of non- consumptive predator effects in terrestrial and marine communities, the possibility that predation risk induces changes in diving behavior has only recently been recognized. We tested whether pied cormorants (Phalacrocorax varius) modify their diving behavior in response to spatio-temporal variation in tiger shark (Galeocerdo cuvier) abundance in the relatively pristine seagrass ecosystem of Shark Bay, Australia. As theory predicted, cormorants reduced the duration of the most dangerous component of the dive cycle by reducing the proportion of time spent at the surface as predation risk increased, but only in the most dangerous habitat. Contrary to model predictions, cormorants accomplished this reduction by increasing dive durations while maintaining similar post-dive surface intervals (leading to lower diving rates). By implication, foraging cormorants may be working harder during high-risk periods and in high-risk habitats to minimize their exposure to predators at the surface. Our finding that cormorants modify their diving behavior in response to spatial and temporal variation in predation risk suggests that the effects of predators on diving species may be greater, and manifest through more pathways, than is currently appreciated. Future studies of diving species, including those considered "top predators," must explicitly consider the potential importance of predation risk. Furthermore, diving behavior as an index of patch quality should be used cautiously when divers are threatened by predators, which is often the case.
{"title":"Predation Risk Influences the Diving Behavior of a Marine Mesopredator~!2009-08-31~!2010-01-25~!2010-04-29~!","authors":"M. M. Dunphy-Daly, M. Heithaus, Aaron J. Wirsing, J. Mardon, D. Burkholder","doi":"10.2174/1874213001003030008","DOIUrl":"https://doi.org/10.2174/1874213001003030008","url":null,"abstract":"Exploring factors that influence diving behavior is critical to understanding energy budgets, habitat use, and exploitation rates of prey. Optimal diving behavior studies have focused primarily on trade-offs between oxygen recovery at the surface and energy intake at depth. General predictions from these models are often supported by empirical data, but a mismatch exists between theory and data that has led to increasingly complex models. Despite the importance of non- consumptive predator effects in terrestrial and marine communities, the possibility that predation risk induces changes in diving behavior has only recently been recognized. We tested whether pied cormorants (Phalacrocorax varius) modify their diving behavior in response to spatio-temporal variation in tiger shark (Galeocerdo cuvier) abundance in the relatively pristine seagrass ecosystem of Shark Bay, Australia. As theory predicted, cormorants reduced the duration of the most dangerous component of the dive cycle by reducing the proportion of time spent at the surface as predation risk increased, but only in the most dangerous habitat. Contrary to model predictions, cormorants accomplished this reduction by increasing dive durations while maintaining similar post-dive surface intervals (leading to lower diving rates). By implication, foraging cormorants may be working harder during high-risk periods and in high-risk habitats to minimize their exposure to predators at the surface. Our finding that cormorants modify their diving behavior in response to spatial and temporal variation in predation risk suggests that the effects of predators on diving species may be greater, and manifest through more pathways, than is currently appreciated. Future studies of diving species, including those considered \"top predators,\" must explicitly consider the potential importance of predation risk. Furthermore, diving behavior as an index of patch quality should be used cautiously when divers are threatened by predators, which is often the case.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"15 1","pages":"8-15"},"PeriodicalIF":0.0,"publicationDate":"2010-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68055082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-13DOI: 10.2174/1874213001003010029
M. Kashiwada, Shunji Ohta
To describe the temporal and geographic distribution of the malaria vector mosquito (Anopheles) at a fine resolution, we modeled the relationship between mosquito life history and climate conditions, focusing on temperature- dependent development of the mosquito. Because Anopheles has aquatic immature life stages, the model was designed to incorporate information on surface moisture conditions suitable for the mosquito. Development was estimated using either air or water temperature, depending on the developmental stage. The model was able to predict seasonal patterns of occurrence of Anopheles at representative sites with reasonable accuracy. Individual emergence of mosquitoes was limited by low water temperatures and/or low moisture conditions at the soil surface in cold or dry seasons. This model was then applied to obtain the geographic distribution of Anopheles occurrence in Monsoon Asia. Spatio-temporal emergence of the Anopheles mosquito was successfully represented using the model and simple climate data. This model can be used to predict the distribution of the mosquito for malaria risk assessments under future scenarios involving climate change and the effects of El Nino-Southern Oscillation events.
{"title":"Modeling the spatio-temporal distribution of the Anopheles mosquito based on life history and surface water conditions","authors":"M. Kashiwada, Shunji Ohta","doi":"10.2174/1874213001003010029","DOIUrl":"https://doi.org/10.2174/1874213001003010029","url":null,"abstract":"To describe the temporal and geographic distribution of the malaria vector mosquito (Anopheles) at a fine resolution, we modeled the relationship between mosquito life history and climate conditions, focusing on temperature- dependent development of the mosquito. Because Anopheles has aquatic immature life stages, the model was designed to incorporate information on surface moisture conditions suitable for the mosquito. Development was estimated using either air or water temperature, depending on the developmental stage. The model was able to predict seasonal patterns of occurrence of Anopheles at representative sites with reasonable accuracy. Individual emergence of mosquitoes was limited by low water temperatures and/or low moisture conditions at the soil surface in cold or dry seasons. This model was then applied to obtain the geographic distribution of Anopheles occurrence in Monsoon Asia. Spatio-temporal emergence of the Anopheles mosquito was successfully represented using the model and simple climate data. This model can be used to predict the distribution of the mosquito for malaria risk assessments under future scenarios involving climate change and the effects of El Nino-Southern Oscillation events.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"29-40"},"PeriodicalIF":0.0,"publicationDate":"2010-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68053708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-07DOI: 10.2174/1874213001003010026
D. Naya
A huge advance in our understanding on the relevance of phenotypic plasticity in evolutionary processes has taken place during the last decades. However, there are several specific topics in which the phenotypic plasticity framework has not been deeply considered. One of these topics is our current interpretation of trait repeatability, which is defined as the consistency of a trait over time (typically measured by the intraclass correlation coefficient). Common sense, as well as consideration based on quantitative genetics, suggests that the demonstration of significant repeatability of a trait necessarily precedes any attempt to demonstrate its selective significance. However, this statement is based on the vision that trait variation over time is in some point in between no change (i.e., fixed traits) and completely random variation. Here, I show, through a hypothetical (but realistic) example, that flexible traits able to respond to environmental factors randomly distributed among individuals can evolve through natural selection without showing a significant repeatability value.
{"title":"Why May Repeatability of Highly Flexible Traits Say Little about their Evolutionary Potential?~!2009-10-27~!2010-02-24~!2010-03-22~!","authors":"D. Naya","doi":"10.2174/1874213001003010026","DOIUrl":"https://doi.org/10.2174/1874213001003010026","url":null,"abstract":"A huge advance in our understanding on the relevance of phenotypic plasticity in evolutionary processes has taken place during the last decades. However, there are several specific topics in which the phenotypic plasticity framework has not been deeply considered. One of these topics is our current interpretation of trait repeatability, which is defined as the consistency of a trait over time (typically measured by the intraclass correlation coefficient). Common sense, as well as consideration based on quantitative genetics, suggests that the demonstration of significant repeatability of a trait necessarily precedes any attempt to demonstrate its selective significance. However, this statement is based on the vision that trait variation over time is in some point in between no change (i.e., fixed traits) and completely random variation. Here, I show, through a hypothetical (but realistic) example, that flexible traits able to respond to environmental factors randomly distributed among individuals can evolve through natural selection without showing a significant repeatability value.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"26-28"},"PeriodicalIF":0.0,"publicationDate":"2010-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68053691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-16DOI: 10.2174/1874213001003010014
J. M H Knops, D. Wedin, S. Naeem
Many studies in ecosystem ecology argue for strong control of litter quality over nitrogen (N) cycling. We developed a model for temperate grasslands to test the importance of litter quality in decomposition for N and phosphorus (P) cycling based on the following premises. First, terrestrial N and P cycling differ fundamentally because N is a structural component of the soil organic matter (SOM), whereas P is not. Secondly, SOM has a much lower C:N ratio than litter inputs. Thirdly, litter decomposition follows an exponential decay with 20% of the original litter mass turning into SOM. Fourth, litter N concentration shows an exponential increase during decomposition, whereas P does not change and is released proportionally to the litter mass. Based on these premises we constructed a model which shows that 0.75% N is a critical initial litter concentration at which concentration all N is immobilized and no N is released from the litter. Thus at 0.75% N of the litter all net N mineralization is through SOM decomposition and not through litter decomposition. Phosphorus, in contrast, is primarily released in the early stages of litter decomposition. Empirical tests of these model predictions support the applicability of the model to temperate grassland ecosystems. This model predicts that N mineralization from SOM is much more important than mineralization from litter and that plant litter quality differences alone cannot explain ecosystem N cycling patterns. Phosphorus, in contrast, does cycle largely through litter decomposition, and plant litter quality differences are the dominant factor in determining ecosystem P cycling feedbacks.
{"title":"The Role of Litter Quality Feedbacks in Terrestrial Nitrogen and Phosphorus Cycling","authors":"J. M H Knops, D. Wedin, S. Naeem","doi":"10.2174/1874213001003010014","DOIUrl":"https://doi.org/10.2174/1874213001003010014","url":null,"abstract":"Many studies in ecosystem ecology argue for strong control of litter quality over nitrogen (N) cycling. We developed a model for temperate grasslands to test the importance of litter quality in decomposition for N and phosphorus (P) cycling based on the following premises. First, terrestrial N and P cycling differ fundamentally because N is a structural component of the soil organic matter (SOM), whereas P is not. Secondly, SOM has a much lower C:N ratio than litter inputs. Thirdly, litter decomposition follows an exponential decay with 20% of the original litter mass turning into SOM. Fourth, litter N concentration shows an exponential increase during decomposition, whereas P does not change and is released proportionally to the litter mass. Based on these premises we constructed a model which shows that 0.75% N is a critical initial litter concentration at which concentration all N is immobilized and no N is released from the litter. Thus at 0.75% N of the litter all net N mineralization is through SOM decomposition and not through litter decomposition. Phosphorus, in contrast, is primarily released in the early stages of litter decomposition. Empirical tests of these model predictions support the applicability of the model to temperate grassland ecosystems. This model predicts that N mineralization from SOM is much more important than mineralization from litter and that plant litter quality differences alone cannot explain ecosystem N cycling patterns. Phosphorus, in contrast, does cycle largely through litter decomposition, and plant litter quality differences are the dominant factor in determining ecosystem P cycling feedbacks.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"14-25"},"PeriodicalIF":0.0,"publicationDate":"2010-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68053979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-10DOI: 10.2174/1874213001003020024
Kangyou Huang, Zhuo Zheng, L. François, D. Guan, R. Cheddadi
Predicting future ecosystems changes is necessary for better managing human resources. Such forecasting requires robust vegetation models which have been tested versus observed field data. Nowadays, it is very common that a simulation model is firstly validated using modern observed data and then tested versus palaeodata. In a sense, ecological data represent the natural laboratory for modelers. Thus, palaeo and actuo-ecological data are key points when dealing with predicting future changes. The present work represents the first step in such data-model comparison approach. Here, we use only modern plants distributions to test the robustness of our ecosystems definitions and use these definitions for testing a dynamic vegetation model. We have defined twenty-nine Bioclimatic affinity groups (BAGs) for 196 dominant plant species including trees, shrubs and herbs in China. These BAGs are characterized by the phenology and the climatic tolerances of the species they include. They are detailed enough to describe all vegetation types in China including the tropical, the subtropical, the temperate and the high altitude (Tibet Plateau) ecosystems. The climatic thresholds of these 29 BAGs were then used to test and validate a global dynamic vegetation model (CARAIB). The simulated BAGs are in good agreement with those observed in China, especially in the Tibetan Plateau and in the subtropical ecosystems. Broadly, all simulated BAGs fit quite well with the modern distribution. However, they all cover larger areas than the observed distributions, especially in the temperate region and in some areas in the northwest and the tropical zone. These discrepancies between simulated and observed distributions are related to the fact that the vegetation models simulate potential distributions. In China during recent decades natural ecosystems, mostly in the temperate zone, have been strongly altered in their species composition and geographical extent by different human activities such as the intense cultivation, deforestation, introduction of fast growing species and grazing.
{"title":"Plants Bioclimatic Affinity Groups in China: Observed vs. Simulated Ranges","authors":"Kangyou Huang, Zhuo Zheng, L. François, D. Guan, R. Cheddadi","doi":"10.2174/1874213001003020024","DOIUrl":"https://doi.org/10.2174/1874213001003020024","url":null,"abstract":"Predicting future ecosystems changes is necessary for better managing human resources. Such forecasting requires robust vegetation models which have been tested versus observed field data. Nowadays, it is very common that a simulation model is firstly validated using modern observed data and then tested versus palaeodata. In a sense, ecological data represent the natural laboratory for modelers. Thus, palaeo and actuo-ecological data are key points when dealing with predicting future changes. The present work represents the first step in such data-model comparison approach. Here, we use only modern plants distributions to test the robustness of our ecosystems definitions and use these definitions for testing a dynamic vegetation model. We have defined twenty-nine Bioclimatic affinity groups (BAGs) for 196 dominant plant species including trees, shrubs and herbs in China. These BAGs are characterized by the phenology and the climatic tolerances of the species they include. They are detailed enough to describe all vegetation types in China including the tropical, the subtropical, the temperate and the high altitude (Tibet Plateau) ecosystems. The climatic thresholds of these 29 BAGs were then used to test and validate a global dynamic vegetation model (CARAIB). The simulated BAGs are in good agreement with those observed in China, especially in the Tibetan Plateau and in the subtropical ecosystems. Broadly, all simulated BAGs fit quite well with the modern distribution. However, they all cover larger areas than the observed distributions, especially in the temperate region and in some areas in the northwest and the tropical zone. These discrepancies between simulated and observed distributions are related to the fact that the vegetation models simulate potential distributions. In China during recent decades natural ecosystems, mostly in the temperate zone, have been strongly altered in their species composition and geographical extent by different human activities such as the intense cultivation, deforestation, introduction of fast growing species and grazing.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"6 1","pages":"24-42"},"PeriodicalIF":0.0,"publicationDate":"2010-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-05DOI: 10.2174/1874213001003020006
C. Whitlock, P. Higuera, D. McWethy, C. Briles
Fire is well recognized as a key Earth system process, but its causes and influences vary greatly across spatial and temporal scales. The controls of fire are often portrayed as a set of superimposed triangles, with processes ranging from oxygen to weather to climate, combustion to fuel to vegetation, and local to landscape to regional drivers over broadening spatial and lengthening temporal scale. Most ecological studies and fire management plans consider the effects of fire-weather and fuels on local to sub-regional scales and time frames of years to decades. Fire reconstructions developed from high-resolution tree-ring records and lake-sediment data that span centuries to millennia offer unique insights about fire's role that cannot otherwise be obtained. Such records help disclose the historical range of variability in fire activity over the duration of a vegetation type; the role of large-scale changes of climate, such as seasonal changes in summer insolation; the consequences of major reorganizations in vegetation; and the influence of prehistoric human activity in different ecological settings. This paleoecological perspective suggests that fire-regime definitions, which focus on the characteristic frequency, size and intensity of fire and particular fuel types, should be reconceptualized to better include the controls of fire regimes over the duration of a particular biome. We suggest that approaches currently used to analyze fire regimes across multiple spatial scales should be employed to examine fire occurrence across multiple temporal scales. Such cross-scale patterns would better reveal the full variability of particular fire regimes and their controls, and provide relevant information for the types of fire regimes likely to occur in the future with projected climate and land-use change.
{"title":"Paleoecological Perspectives on Fire Ecology: Revisiting the Fire-Regime Concept~!2009-09-02~!2009-11-09~!2010-03-05~!","authors":"C. Whitlock, P. Higuera, D. McWethy, C. Briles","doi":"10.2174/1874213001003020006","DOIUrl":"https://doi.org/10.2174/1874213001003020006","url":null,"abstract":"Fire is well recognized as a key Earth system process, but its causes and influences vary greatly across spatial and temporal scales. The controls of fire are often portrayed as a set of superimposed triangles, with processes ranging from oxygen to weather to climate, combustion to fuel to vegetation, and local to landscape to regional drivers over broadening spatial and lengthening temporal scale. Most ecological studies and fire management plans consider the effects of fire-weather and fuels on local to sub-regional scales and time frames of years to decades. Fire reconstructions developed from high-resolution tree-ring records and lake-sediment data that span centuries to millennia offer unique insights about fire's role that cannot otherwise be obtained. Such records help disclose the historical range of variability in fire activity over the duration of a vegetation type; the role of large-scale changes of climate, such as seasonal changes in summer insolation; the consequences of major reorganizations in vegetation; and the influence of prehistoric human activity in different ecological settings. This paleoecological perspective suggests that fire-regime definitions, which focus on the characteristic frequency, size and intensity of fire and particular fuel types, should be reconceptualized to better include the controls of fire regimes over the duration of a particular biome. We suggest that approaches currently used to analyze fire regimes across multiple spatial scales should be employed to examine fire occurrence across multiple temporal scales. Such cross-scale patterns would better reveal the full variability of particular fire regimes and their controls, and provide relevant information for the types of fire regimes likely to occur in the future with projected climate and land-use change.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"6-23"},"PeriodicalIF":0.0,"publicationDate":"2010-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-02-03DOI: 10.2174/1874213001003030001
J. Laundré, L. Hernández, W. Ripple
Predation risk" and "fear" are concepts well established in animal behavior literature. We expand these concepts to develop the model of the "landscape of fear". The landscape of fear represents relative levels of predation risk as peaks and valleys that reflect the level of fear of predation a prey experiences in different parts of its area of use. We provide observations in support of this model regarding changes in predation risk with respect to habitat types, and terrain characteristics. We postulate that animals have the ability to learn and can respond to differing levels of predation risk. We propose that the landscape of fear can be quantified with the use of well documented existing methods such as giving- up densities, vigilance observations, and foraging surveys of plants. We conclude that the landscape of fear is a useful visual model and has the potential to become a unifying ecological concept.
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Pub Date : 2010-01-20DOI: 10.2174/1874213001003010001
J. Moya‐Laraño
Environmental gradients (such as average annual temperature increasing towards the tropics) are numerous across the globe. Here I propose a theory, comprised of progressive hypotheses, which links temperature and water availability to the maintenance of high genetic and phenotypic diversity in the tropics through enhanced biotic interactions. In terrestrial ecosystems higher temperatures and water availability, by allowing higher rates of mobility, growth and reproduction of organisms, should lead to higher rates of encounter among individuals in communities. Due to this, interactions in wet and warm environments, such as tropical rainforests, should be both more frequent and more diverse regardless of the number of species present. This diversity of interactions is illustrated at the genotype level, stressing whether genotypes interact positively or negatively with other genotypes, and considering species, as well as individuals, as genotypes. Such biotic interactions in environments can generate strong genotype-environment interactions that can promote the maintenance of high levels of (functional) genetic and phenotypic diversity. This can subsequently facilitate coexistence and speciation processes. The paper finishes by proposing future research to test the hypotheses and hence the overall theory presented here.
{"title":"Can temperature and water availability contribute to the maintenance of latitudinal diversity by increasing the rate of biotic interactions","authors":"J. Moya‐Laraño","doi":"10.2174/1874213001003010001","DOIUrl":"https://doi.org/10.2174/1874213001003010001","url":null,"abstract":"Environmental gradients (such as average annual temperature increasing towards the tropics) are numerous across the globe. Here I propose a theory, comprised of progressive hypotheses, which links temperature and water availability to the maintenance of high genetic and phenotypic diversity in the tropics through enhanced biotic interactions. In terrestrial ecosystems higher temperatures and water availability, by allowing higher rates of mobility, growth and reproduction of organisms, should lead to higher rates of encounter among individuals in communities. Due to this, interactions in wet and warm environments, such as tropical rainforests, should be both more frequent and more diverse regardless of the number of species present. This diversity of interactions is illustrated at the genotype level, stressing whether genotypes interact positively or negatively with other genotypes, and considering species, as well as individuals, as genotypes. Such biotic interactions in environments can generate strong genotype-environment interactions that can promote the maintenance of high levels of (functional) genetic and phenotypic diversity. This can subsequently facilitate coexistence and speciation processes. The paper finishes by proposing future research to test the hypotheses and hence the overall theory presented here.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"18 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2010-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68053930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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