Pub Date : 2011-03-24DOI: 10.2174/1874213001003020068
H. Birks, O. Heiri, H. Seppä, A. Bjune
The importance of reconstructing past environments quantitatively in palaeoecology is reviewed by showing that many ecological questions asked of palaeoecological data commonly involve the reconstructions of past environment. Three basic approaches to reconstructing past climate from palaeoecological data are outlined and discussed in terms of their assumptions, strengths, and weaknesses. These approaches are the indicator-species approach involving bioclimateenvelope modelling; the assemblage approach involving modern analogue techniques and response surfaces; and the multivariate calibration-function approach. Topics common to all approaches are reviewed – presentation and interpretation, evaluation and validation, comparison, and general limitations of climate reconstructions. Challenges and possible future developments are presented and the potential future role of quantitative climate reconstructions in palaeoecology is summarised.
{"title":"Strengths and Weaknesses of Quantitative Climate Reconstructions Based on Late-Quaternary Biological Proxies","authors":"H. Birks, O. Heiri, H. Seppä, A. Bjune","doi":"10.2174/1874213001003020068","DOIUrl":"https://doi.org/10.2174/1874213001003020068","url":null,"abstract":"The importance of reconstructing past environments quantitatively in palaeoecology is reviewed by showing that many ecological questions asked of palaeoecological data commonly involve the reconstructions of past environment. Three basic approaches to reconstructing past climate from palaeoecological data are outlined and discussed in terms of their assumptions, strengths, and weaknesses. These approaches are the indicator-species approach involving bioclimateenvelope modelling; the assemblage approach involving modern analogue techniques and response surfaces; and the multivariate calibration-function approach. Topics common to all approaches are reviewed – presentation and interpretation, evaluation and validation, comparison, and general limitations of climate reconstructions. Challenges and possible future developments are presented and the potential future role of quantitative climate reconstructions in palaeoecology is summarised.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"68-110"},"PeriodicalIF":0.0,"publicationDate":"2011-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2174/1874213001003020068","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68055006","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 : 2010-12-15DOI: 10.2174/1874213001003010111
Roman Bucher, J. Herrmann, Christof Schüepp, F. Herzog, M. Entling
Effects of habitat fragmentation vary greatly between organisms. Traits such as dispersal mode and habitat preference may explain these differences. We predict that organisms with low dispersal abilities respond mainly to habitat isolation whereas aerial colonisers respond to the amount of suitable habitats at the landscape scale. To test these predictions 30 sites were chosen that varied independently in the level of isolation from woody habitats and in the percentage of woody habitats in 500 m circumference. At each site seven cherry trees were established. Overwintering arthropods were sampled using cardboard hides. Glue rings were attached around tree stems to distinguish between walking and aerial colonisers. As predicted for walking dispersers, earwig abundance was strongly affected by habitat isolation. In contrast, three species of ballooning spiders responded neither to glue rings nor to habitat isolation. Instead they were affected by habitat amount in accordance with their preferred habitats. These results strongly encourage the use of species traits to predict effects of landscape fragmentation on organisms. However, additional factors such as interactions between species groups need also to be taken into account.
{"title":"Arthropod Colonisation of Trees in Fragmented Landscapes Depends on Species Traits","authors":"Roman Bucher, J. Herrmann, Christof Schüepp, F. Herzog, M. Entling","doi":"10.2174/1874213001003010111","DOIUrl":"https://doi.org/10.2174/1874213001003010111","url":null,"abstract":"Effects of habitat fragmentation vary greatly between organisms. Traits such as dispersal mode and habitat preference may explain these differences. We predict that organisms with low dispersal abilities respond mainly to habitat isolation whereas aerial colonisers respond to the amount of suitable habitats at the landscape scale. To test these predictions 30 sites were chosen that varied independently in the level of isolation from woody habitats and in the percentage of woody habitats in 500 m circumference. At each site seven cherry trees were established. Overwintering arthropods were sampled using cardboard hides. Glue rings were attached around tree stems to distinguish between walking and aerial colonisers. As predicted for walking dispersers, earwig abundance was strongly affected by habitat isolation. In contrast, three species of ballooning spiders responded neither to glue rings nor to habitat isolation. Instead they were affected by habitat amount in accordance with their preferred habitats. These results strongly encourage the use of species traits to predict effects of landscape fragmentation on organisms. However, additional factors such as interactions between species groups need also to be taken into account.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"111-117"},"PeriodicalIF":0.0,"publicationDate":"2010-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054884","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 : 2010-12-03DOI: 10.2174/1874213001003030022
John L. Orrock, Lawerence M. Dill, A. Sih, Johnathan H. Grabowski, S. Peacor, B. Peckarsky, E. Preisser, J. Vonesh, E. Werner
Predators can have remote effects on prey populations that are connected by migration (i.e. prey metapopulations) because predator-mediated changes in prey behavior and abundance effectively transmit the impact of predators into predator-free prey populations. Behavioral changes in prey that might give rise to remote effects are altered rates of migration or activity in the presence of predation risk (called non-consumptive effects, fear- or µ-driven effects, and risk effects). Changes in prey abundance that may result in remote effects arise from changes in prey density due to direct predation (i.e. consumptive effects, also called N-driven effects and predation effects). Remote effects provide a different perspective on both predator-prey interactions and spatial subsidies, illustrating how the interplay among space, time, behavior, and consumption generates emergent spatial dynamics in places where we might not expect them. We describe how strong remote effects of predators may essentially generate "remote control" over the dynamics of local populations, alter the persistence of metapopulations, shift the importance of particular paradigms of metacommunity structure, alter spatial subsidies, and affect evolutionary dynamics. We suggest how experiments might document remote effects and predict that remote effects will be an important component of prey dynamics under several common scenarios: when predators induce large changes in prey dispersal behavior, when predators dramatically reduce the number of prey available to disperse, when prey movement dynamics occur over greater distances or shorter timescales than predator movement, and when prey abundance is not already limited by competitors or conspecifics.
{"title":"Predator Effects in Predator-Free Space: the Remote Effects of Predators on Prey","authors":"John L. Orrock, Lawerence M. Dill, A. Sih, Johnathan H. Grabowski, S. Peacor, B. Peckarsky, E. Preisser, J. Vonesh, E. Werner","doi":"10.2174/1874213001003030022","DOIUrl":"https://doi.org/10.2174/1874213001003030022","url":null,"abstract":"Predators can have remote effects on prey populations that are connected by migration (i.e. prey metapopulations) because predator-mediated changes in prey behavior and abundance effectively transmit the impact of predators into predator-free prey populations. Behavioral changes in prey that might give rise to remote effects are altered rates of migration or activity in the presence of predation risk (called non-consumptive effects, fear- or µ-driven effects, and risk effects). Changes in prey abundance that may result in remote effects arise from changes in prey density due to direct predation (i.e. consumptive effects, also called N-driven effects and predation effects). Remote effects provide a different perspective on both predator-prey interactions and spatial subsidies, illustrating how the interplay among space, time, behavior, and consumption generates emergent spatial dynamics in places where we might not expect them. We describe how strong remote effects of predators may essentially generate \"remote control\" over the dynamics of local populations, alter the persistence of metapopulations, shift the importance of particular paradigms of metacommunity structure, alter spatial subsidies, and affect evolutionary dynamics. We suggest how experiments might document remote effects and predict that remote effects will be an important component of prey dynamics under several common scenarios: when predators induce large changes in prey dispersal behavior, when predators dramatically reduce the number of prey available to disperse, when prey movement dynamics occur over greater distances or shorter timescales than predator movement, and when prey abundance is not already limited by competitors or conspecifics.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"22-30"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68055094","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 : 2010-11-05DOI: 10.2174/1874213001003010016
L. Trebatická, T. Ketola, Marko Haapakoski, Annika Opperbeck, H. Ylönen
A predator has a large impact on its prey. Besides a direct lethal effect, mere predator presence can increase stress and vigilance reflecting on prey behaviour and physiology. Such an effect should be stronger in more vulnerable prey individuals, depending e.g. on sex and reproductive status. We studied the short-term physiological response, the change in CO 2 production as a measure of metabolism, and the behavioural response in non-pregnant and pregnant bank vole Myodes glareolus females. The bank vole is a common small mammal in boreal forest environments and one of the major prey species for predators, especially small mustelids. The least weasel Mustela nivalis nivalis is a vole specialist and the only predator which can enter the tunnels of voles and their nests. Furthermore, weasels, like all mustelids, have strong scents used in social communication, and weasel odour may be used as a cue of increased risk by prey individuals. We simulated an increase in predation risk by the injection of least weasel odour into an open-flow respirometry system housing either a pregnant or non-pregnant female bank vole. We focused on immediate and post-stress response in CO 2 production and changes in female behaviour. We found that injections of pure air ("disturbance") or of weasel odour ("threat") similarly increased CO 2 production. Surprisingly, non-pregnant females responded to stress more strongly than pregnant ones, i.e. the increase in CO 2 was higher. Weasel odour increased female activity more than the injection of air. According to our prediction, after the disappearance of weasel odour there were no differences in physiological or behavioural parameters between pregnant and non-pregnant females. Contrary to our prediction, our results showed quite similar response to harmless air disturbance and the risky weasel cue. However, it may be that in a situation of sudden change in environment, regardless of its nature, a short-term vigilance response is a better response than more costly antipredatory behaviours.
{"title":"Is Fear a Factor in Voles? Short Term Physiological and Behavioural Response to Predation Stress","authors":"L. Trebatická, T. Ketola, Marko Haapakoski, Annika Opperbeck, H. Ylönen","doi":"10.2174/1874213001003010016","DOIUrl":"https://doi.org/10.2174/1874213001003010016","url":null,"abstract":"A predator has a large impact on its prey. Besides a direct lethal effect, mere predator presence can increase stress and vigilance reflecting on prey behaviour and physiology. Such an effect should be stronger in more vulnerable prey individuals, depending e.g. on sex and reproductive status. We studied the short-term physiological response, the change in CO 2 production as a measure of metabolism, and the behavioural response in non-pregnant and pregnant bank vole Myodes glareolus females. The bank vole is a common small mammal in boreal forest environments and one of the major prey species for predators, especially small mustelids. The least weasel Mustela nivalis nivalis is a vole specialist and the only predator which can enter the tunnels of voles and their nests. Furthermore, weasels, like all mustelids, have strong scents used in social communication, and weasel odour may be used as a cue of increased risk by prey individuals. We simulated an increase in predation risk by the injection of least weasel odour into an open-flow respirometry system housing either a pregnant or non-pregnant female bank vole. We focused on immediate and post-stress response in CO 2 production and changes in female behaviour. We found that injections of pure air (\"disturbance\") or of weasel odour (\"threat\") similarly increased CO 2 production. Surprisingly, non-pregnant females responded to stress more strongly than pregnant ones, i.e. the increase in CO 2 was higher. Weasel odour increased female activity more than the injection of air. According to our prediction, after the disappearance of weasel odour there were no differences in physiological or behavioural parameters between pregnant and non-pregnant females. Contrary to our prediction, our results showed quite similar response to harmless air disturbance and the risky weasel cue. However, it may be that in a situation of sudden change in environment, regardless of its nature, a short-term vigilance response is a better response than more costly antipredatory behaviours.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"16-21"},"PeriodicalIF":0.0,"publicationDate":"2010-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054177","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 : 2010-11-01DOI: 10.2174/1874213001003010095
Bo Deng
The purpose of this paper is to incorporate well-established ecological principles into a foodweb model consisting of four trophic levels --- abiotic resources, plants, herbivores, and carnivores. The underlining principles include Kimura's neutral theory of genetic evolution, Liebig's Law of the Minimum for plant growth, Holling's functionals for herbivore foraging and carnivore predation, the One-Life Rule for all organisms, and Lotka-Volterra's model for intra- and interspecific competitions. Numerical simulations of the model led to the following statistical findings: (a) particular foodwebs can give contradicting observations on biodiversity and productivity, in particular, all known functional forms -- - positive, negative, sigmoidal, and unimodal correlations are present in the model; (b) drifting stable equilibria should be expected for ecosystems regardless of their size; (c) resource abundance and specific competitions are the main determining factors for biodiversity, with intraspecific competition enhancing diversity while interspecific competition impeding diversity; (d) endangered species are expected always and loss in lower trophic endangered species are expected at trophication, i.e. the establishment of a higher trophic level of a community. These findings may shed lights on some ongoing debates on biodiversity. In particular, finding (a) implies that the diversity vs. ecosystems functioning debate is most likely the result of incompatible particular observations each cannot be generalized. In particular, general causality should not be expected between diversity and productivity. Finding (b) does not support May's theory that large ecosystems are inherently unstable nor Eton's theory that stability requires diversity. However, it lends a strong support to the energetic theory for the latitudinal diversity gradient. Finding (c) supports Darwin's observation on the effect of interspecific competition on diversity. Finding (d) implies that loss of diversity is inevitable with the appearance of a super species like the human race. Our method and result also suggest that although the evolution of particular species cannot be predicted, some general statistic patterns appear to persist. In addition to the aforementioned findings, these persisting patterns include: the trophic succession, the trophic biomass separation in orders of magnitude, the upper bounds in biodiversity in relationship to the intensities of specific competitions despite the enormous possible number of species allowed by genetic mutations.
{"title":"From Energy Gradient and Natural Selection to Biodiversity and Stability of Ecosystems","authors":"Bo Deng","doi":"10.2174/1874213001003010095","DOIUrl":"https://doi.org/10.2174/1874213001003010095","url":null,"abstract":"The purpose of this paper is to incorporate well-established ecological principles into a foodweb model consisting of four trophic levels --- abiotic resources, plants, herbivores, and carnivores. The underlining principles include Kimura's neutral theory of genetic evolution, Liebig's Law of the Minimum for plant growth, Holling's functionals for herbivore foraging and carnivore predation, the One-Life Rule for all organisms, and Lotka-Volterra's model for intra- and interspecific competitions. Numerical simulations of the model led to the following statistical findings: (a) particular foodwebs can give contradicting observations on biodiversity and productivity, in particular, all known functional forms -- - positive, negative, sigmoidal, and unimodal correlations are present in the model; (b) drifting stable equilibria should be expected for ecosystems regardless of their size; (c) resource abundance and specific competitions are the main determining factors for biodiversity, with intraspecific competition enhancing diversity while interspecific competition impeding diversity; (d) endangered species are expected always and loss in lower trophic endangered species are expected at trophication, i.e. the establishment of a higher trophic level of a community. These findings may shed lights on some ongoing debates on biodiversity. In particular, finding (a) implies that the diversity vs. ecosystems functioning debate is most likely the result of incompatible particular observations each cannot be generalized. In particular, general causality should not be expected between diversity and productivity. Finding (b) does not support May's theory that large ecosystems are inherently unstable nor Eton's theory that stability requires diversity. However, it lends a strong support to the energetic theory for the latitudinal diversity gradient. Finding (c) supports Darwin's observation on the effect of interspecific competition on diversity. Finding (d) implies that loss of diversity is inevitable with the appearance of a super species like the human race. Our method and result also suggest that although the evolution of particular species cannot be predicted, some general statistic patterns appear to persist. In addition to the aforementioned findings, these persisting patterns include: the trophic succession, the trophic biomass separation in orders of magnitude, the upper bounds in biodiversity in relationship to the intensities of specific competitions despite the enormous possible number of species allowed by genetic mutations.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"95-110"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054869","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 : 2010-09-15DOI: 10.2174/1874213001003010083
Victoria A. Ranua, C. Weinig
Mating-system expression is sensitive to environmental conditions, and can be an important determinant of lifetime fitness because progeny that are produced via outcrossing vs. selfing may differ in quality. We quantified sexual and asexual reproduction in Viola lanceolata, a regionally threatened species, across populations that varied in disturbance history and across microsites that differed in percent soil moisture, irradiance, and temperature. In V. lanceolata, reproduction can occur sexually through facultatively outcrossing chasmogamous (CH) flowers and obligately selfing cleistogamous (CL) flowers in addition to asexually via stolons. The frequency of individuals producing CH and CL flowers differed among sites as did the frequency of vegetative reproduction. Interestingly, sites also differed in fruit maturation success, with ~33, 100, and 16% of the CH fruits matured in the oldest, intermediate, and most-recently disturbed populations respectively. Analogous site differences in CL fruit maturation were observed. Cleistagamous, but not CH, reproduction was also dependent on percent soil moisture. The observed differences in fruit maturation success likely lead to variable rates of outcrossed vs. self-fertilized seed production; as a consequence, populations are likely to differ in genetic structure and in relative dependence on chasmogamy vs. cleiostogamy for population growth. Finally, CL flower and stolon production were negatively correlated, suggesting a tradeoff between sexual and asexual reproduction that might affect population growth.
{"title":"Mixed-Mating Strategies and their Sensitivity to Abiotic Variation in Viola Lanceolata L. (Violaceae)","authors":"Victoria A. Ranua, C. Weinig","doi":"10.2174/1874213001003010083","DOIUrl":"https://doi.org/10.2174/1874213001003010083","url":null,"abstract":"Mating-system expression is sensitive to environmental conditions, and can be an important determinant of lifetime fitness because progeny that are produced via outcrossing vs. selfing may differ in quality. We quantified sexual and asexual reproduction in Viola lanceolata, a regionally threatened species, across populations that varied in disturbance history and across microsites that differed in percent soil moisture, irradiance, and temperature. In V. lanceolata, reproduction can occur sexually through facultatively outcrossing chasmogamous (CH) flowers and obligately selfing cleistogamous (CL) flowers in addition to asexually via stolons. The frequency of individuals producing CH and CL flowers differed among sites as did the frequency of vegetative reproduction. Interestingly, sites also differed in fruit maturation success, with ~33, 100, and 16% of the CH fruits matured in the oldest, intermediate, and most-recently disturbed populations respectively. Analogous site differences in CL fruit maturation were observed. Cleistagamous, but not CH, reproduction was also dependent on percent soil moisture. The observed differences in fruit maturation success likely lead to variable rates of outcrossed vs. self-fertilized seed production; as a consequence, populations are likely to differ in genetic structure and in relative dependence on chasmogamy vs. cleiostogamy for population growth. Finally, CL flower and stolon production were negatively correlated, suggesting a tradeoff between sexual and asexual reproduction that might affect population growth.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"83-94"},"PeriodicalIF":0.0,"publicationDate":"2010-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054786","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 : 2010-09-03DOI: 10.2174/1874213001003010071
W. Z. Lidicker
The role of mutually beneficial interactions (++, cooperation) is a rapidly growing research field in population dynamics, microevolution, and conservation biology. Such positive influences cause destabilizing pressures in population dynamics (anti-regulating factors), and can generate Allee effects. Not only can large demes benefit from such cooperation, but the loss of cooperation in small demes can produce a minimum threshold density. Interest in these phenomena grew rapidly to the middle of the 20th century, followed by about four decades in which interest waned. In the last 20 years attention to Allee effects has burgeoned once again. This renewal has produced new perspectives, including a more realistic framework for the way populations and communities are organized. A core concept for Allee effects emerges from the historical record and current views on population dynamics: Allee effects are demographic consequences of the collective actions of anti-regulating influences. Recent developments, including proposals for much new terminology, are reviewed and found to be helpful in building mechanistic understanding of the core concept. Support for the growing relevance of Allee effects to conservation biology as well as population and community dynamics is emphasized. Some new avenues for future research directions include improving our abilities to predict life history and environmental features that favor strong anti-regulation and hence Allee effects, the role of mutually positive interspecific relations in community function, and possible role of anti-regulation in restoration ecology.
{"title":"The Allee Effect: Its History and Future Importance","authors":"W. Z. Lidicker","doi":"10.2174/1874213001003010071","DOIUrl":"https://doi.org/10.2174/1874213001003010071","url":null,"abstract":"The role of mutually beneficial interactions (++, cooperation) is a rapidly growing research field in population dynamics, microevolution, and conservation biology. Such positive influences cause destabilizing pressures in population dynamics (anti-regulating factors), and can generate Allee effects. Not only can large demes benefit from such cooperation, but the loss of cooperation in small demes can produce a minimum threshold density. Interest in these phenomena grew rapidly to the middle of the 20th century, followed by about four decades in which interest waned. In the last 20 years attention to Allee effects has burgeoned once again. This renewal has produced new perspectives, including a more realistic framework for the way populations and communities are organized. A core concept for Allee effects emerges from the historical record and current views on population dynamics: Allee effects are demographic consequences of the collective actions of anti-regulating influences. Recent developments, including proposals for much new terminology, are reviewed and found to be helpful in building mechanistic understanding of the core concept. Support for the growing relevance of Allee effects to conservation biology as well as population and community dynamics is emphasized. Some new avenues for future research directions include improving our abilities to predict life history and environmental features that favor strong anti-regulation and hence Allee effects, the role of mutually positive interspecific relations in community function, and possible role of anti-regulation in restoration ecology.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2010-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68053887","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 : 2010-08-13DOI: 10.2174/1874213001003010059
S. A. Inkpen, M. Foellmer
Extreme sexual size dimorphism (SSD) in temperate species is expected to be proximally caused, at least partially, by sex-specific growth rates due to the limited time available for growth and reproduction. Hence sex-specific foraging strategies are predicted to mediate differential growth rates. However, little is known about how sex differences in foraging behaviour and growth trajectories relate to the expression of pronounced SSD. Here we tested for sex-specific foraging strategies and growth rates in juveniles of the highly size dimorphic orb-web spider Argiope aurantia under natural conditions. In a number of web sites, we estimated web height, web size (size of the prey capture area), mesh size, stabilimentum (web decoration) size and length, vegetation density and prey availability. Over four days in the field we also measured spider growth and web site tenacity. Independently of body size, females exhibited faster growth rate than males. When body size and condition were controlled for, we found that females built larger webs, and at sites with greater prey availability compared to males. Males built webs with significantly larger and longer stabilimenta independent of web size. These results indicate that extreme female-biased SSD in A. aurantia is at least partially the result of sex-specific growth rates already in early juvenile stages mediated by sex-specific web design and placement to allow for greater foraging success of females compared to males. We discuss these findings in the context of SSD evolution, and consider whether the sex-specific behaviours detected are more likely consequences or causes of the evolution of extreme SSD.
{"title":"Sex-Specific Foraging Behaviours and Growth Rates in Juveniles Contribute to the Development of Extreme Sexual Size Dimorphism in a Spider~!2010-03-14~!2010-05-31~!2010-08-13~!","authors":"S. A. Inkpen, M. Foellmer","doi":"10.2174/1874213001003010059","DOIUrl":"https://doi.org/10.2174/1874213001003010059","url":null,"abstract":"Extreme sexual size dimorphism (SSD) in temperate species is expected to be proximally caused, at least partially, by sex-specific growth rates due to the limited time available for growth and reproduction. Hence sex-specific foraging strategies are predicted to mediate differential growth rates. However, little is known about how sex differences in foraging behaviour and growth trajectories relate to the expression of pronounced SSD. Here we tested for sex-specific foraging strategies and growth rates in juveniles of the highly size dimorphic orb-web spider Argiope aurantia under natural conditions. In a number of web sites, we estimated web height, web size (size of the prey capture area), mesh size, stabilimentum (web decoration) size and length, vegetation density and prey availability. Over four days in the field we also measured spider growth and web site tenacity. Independently of body size, females exhibited faster growth rate than males. When body size and condition were controlled for, we found that females built larger webs, and at sites with greater prey availability compared to males. Males built webs with significantly larger and longer stabilimenta independent of web size. These results indicate that extreme female-biased SSD in A. aurantia is at least partially the result of sex-specific growth rates already in early juvenile stages mediated by sex-specific web design and placement to allow for greater foraging success of females compared to males. We discuss these findings in the context of SSD evolution, and consider whether the sex-specific behaviours detected are more likely consequences or causes of the evolution of extreme SSD.","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"59-70"},"PeriodicalIF":0.0,"publicationDate":"2010-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68053837","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 : 2010-07-08DOI: 10.2174/1874213001003010048
T. Osawa, H. Mitsuhashi, Hideyuki Niwa, A. Ushimaru
Although dendritic networks within ecosystems have typically been considered a special case of network topology, they have attracted a great deal of attention in recent years. These systems exhibit unique features in that both the nodes and branches provide distinct habitats. Within a river discontinuum context, river confluences, which are nodes of dendritic river networks, are hypothesised to have particular hydrodynamic traits that create heterogeneous habitats through a unique disturbance regime, although this hypothesis has not yet been tested. We tested this hypothesis using a vegetation data set collected from 14 river basin systems in Hyogo Prefecture, Japan. We compared vegetation-patch diversity between confluence and single-flow areas using hierarchical Bayesian models. Our results demonstrated greater vegetation-patch diversity in confluence areas compared to single-flow areas. Our findings support the hypothesis that confluences result in highly heterogeneous habitats. To the best of our knowledge, this is the first empirical report to demonstrate that river confluences have high vegetation-patch diversity. We conclude that network nodes play an important role in maintaining the biodiversity of river networks.
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Pub Date : 2010-07-06DOI: 10.2174/1874213001003020054
Davies A L, Bunting M J
{"title":"Applications of Palaeoecology in Conservation~!2010-03-15~!2010-05-01~!2010-06-22~!","authors":"Davies A L, Bunting M J","doi":"10.2174/1874213001003020054","DOIUrl":"https://doi.org/10.2174/1874213001003020054","url":null,"abstract":"","PeriodicalId":39335,"journal":{"name":"Open Ecology Journal","volume":"3 1","pages":"54-67"},"PeriodicalIF":0.0,"publicationDate":"2010-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68054997","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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