The Allee effect is a density‐dependent phenomenon in which individual fitness increases as population density increases at low population densities. Over the past few decades, a growing number of studies have identified Allee effects in populations using experimental approaches and statistical modeling techniques. These studies have investigated multiple Allee mechanisms (e.g. mate‐finding, predation, resource limitation), across a range of systems and taxa (e.g. plants, vertebrates, invertebrates). This meta‐analysis aims to synthesize studies that experimentally manipulated population density and measured either per capita population growth or fitness components, with the goal of determining whether the ‘magnitude' of the Allee effect (defined here as the positive correlation between population density and population growth or fitness) varies with Allee mechanism across taxonomic groups. A total of 2305 studies were screened, and 62 of these studies met our meta‐analysis inclusion criteria. Within these 62 studies, 155 effect sizes encompassing nine different Allee mechanisms were identified across five broad taxa. When grouped by Allee mechanism and taxa, the magnitude of the Allee effect differed across mechanisms, whereas taxonomic group was less useful at explaining variation in the magnitude of Allee effects. Of the nine Allee mechanisms identified, interspecific competition was associated with the largest Allee effects, followed by fear, pollen limitation and mate limitation. These findings suggest that Allee effects may be more dependent on mechanism than taxa and may function similarly within different taxonomic groups. However, as the majority of experimental Allee effect studies included in this meta‐analysis focused on plants and invertebrates, more research is needed on Allee effects in other taxonomic groups to confirm this conclusion. This first quantitative synthesis of Allee effect research in ecology offers novel insight into how Allee mechanisms affect the manifestation of Allee effects in populations, providing important information for ecologists and conservationists.
{"title":"The magnitude of Allee effects varies across Allee mechanisms, but not taxonomic groups","authors":"Eva J. Muir, Marc J. Lajeunesse, Andrew M. Kramer","doi":"10.1111/oik.10386","DOIUrl":"https://doi.org/10.1111/oik.10386","url":null,"abstract":"The Allee effect is a density‐dependent phenomenon in which individual fitness increases as population density increases at low population densities. Over the past few decades, a growing number of studies have identified Allee effects in populations using experimental approaches and statistical modeling techniques. These studies have investigated multiple Allee mechanisms (e.g. mate‐finding, predation, resource limitation), across a range of systems and taxa (e.g. plants, vertebrates, invertebrates). This meta‐analysis aims to synthesize studies that experimentally manipulated population density and measured either per capita population growth or fitness components, with the goal of determining whether the ‘magnitude' of the Allee effect (defined here as the positive correlation between population density and population growth or fitness) varies with Allee mechanism across taxonomic groups. A total of 2305 studies were screened, and 62 of these studies met our meta‐analysis inclusion criteria. Within these 62 studies, 155 effect sizes encompassing nine different Allee mechanisms were identified across five broad taxa. When grouped by Allee mechanism and taxa, the magnitude of the Allee effect differed across mechanisms, whereas taxonomic group was less useful at explaining variation in the magnitude of Allee effects. Of the nine Allee mechanisms identified, interspecific competition was associated with the largest Allee effects, followed by fear, pollen limitation and mate limitation. These findings suggest that Allee effects may be more dependent on mechanism than taxa and may function similarly within different taxonomic groups. However, as the majority of experimental Allee effect studies included in this meta‐analysis focused on plants and invertebrates, more research is needed on Allee effects in other taxonomic groups to confirm this conclusion. This first quantitative synthesis of Allee effect research in ecology offers novel insight into how Allee mechanisms affect the manifestation of Allee effects in populations, providing important information for ecologists and conservationists.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"11 3 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. F. (Ciska) Veen, Annika T. Vermaat, Judith Sitters, Elisabeth S. Bakker
Human‐induced nutrient eutrophication is a major threat to grassland biodiversity, because it promotes the dominance of fast‐growing plants. Negative impacts of fertilization on plant biodiversity may be offset by grazing by large vertebrate herbivores. However, whether grazers also mitigate impacts of nutrient addition on insects is less well understood. We use a field experiment to test how plant communities and abundances of pollinators and grasshoppers respond to nutrient addition and grazing by different assemblages of large herbivores, i.e. access by all herbivores (including cattle and horses), access by wild herbivores only (wild boar and deer), no access by large herbivores. Plant biomass increased, plant diversity decreased and community composition shifted towards lower forb cover in response to fertilization, but only in the absence of all herbivores. Flower visitation by Hymenoptera (bees and wasps), i.e. the most abundant pollinator group, was reduced by nutrient addition only in the absence of all herbivores and was positively related to flowering plant richness. In contrast, flower visitation by Diptera (e.g. hoverflies) was enhanced by fertilization, but not affected by grazing. Orthoptera (grasshopper) abundance was reduced by grazing and enhanced by nutrient addition, with positive impacts of fertilization tending to be stronger in plots with only wild or no herbivores. The abundance of grasshoppers was positively related to grass biomass. We conclude that vertebrate herbivores can offset impacts of fertilization on both plant and insect communities, making grazing by large mammals an essential tool to protect insects, particularly pollinators. Most responses to nutrient addition were only apparent in plots without any large herbivores, suggesting that wild herbivores alone could already mitigate nutrient impacts. We also show that insects with contrasting feeding guilds may be favoured by fertilized, ungrazed conditions. Therefore, creating a mosaic of patches grazed at different intensities will enhance overall insect biodiversity.
{"title":"Vertebrate grazing can mitigateimpacts of nutrient addition on plant diversity and insect abundance in a semi‐natural grassland","authors":"G. F. (Ciska) Veen, Annika T. Vermaat, Judith Sitters, Elisabeth S. Bakker","doi":"10.1111/oik.10422","DOIUrl":"https://doi.org/10.1111/oik.10422","url":null,"abstract":"Human‐induced nutrient eutrophication is a major threat to grassland biodiversity, because it promotes the dominance of fast‐growing plants. Negative impacts of fertilization on plant biodiversity may be offset by grazing by large vertebrate herbivores. However, whether grazers also mitigate impacts of nutrient addition on insects is less well understood. We use a field experiment to test how plant communities and abundances of pollinators and grasshoppers respond to nutrient addition and grazing by different assemblages of large herbivores, i.e. access by all herbivores (including cattle and horses), access by wild herbivores only (wild boar and deer), no access by large herbivores. Plant biomass increased, plant diversity decreased and community composition shifted towards lower forb cover in response to fertilization, but only in the absence of all herbivores. Flower visitation by Hymenoptera (bees and wasps), i.e. the most abundant pollinator group, was reduced by nutrient addition only in the absence of all herbivores and was positively related to flowering plant richness. In contrast, flower visitation by Diptera (e.g. hoverflies) was enhanced by fertilization, but not affected by grazing. Orthoptera (grasshopper) abundance was reduced by grazing and enhanced by nutrient addition, with positive impacts of fertilization tending to be stronger in plots with only wild or no herbivores. The abundance of grasshoppers was positively related to grass biomass. We conclude that vertebrate herbivores can offset impacts of fertilization on both plant and insect communities, making grazing by large mammals an essential tool to protect insects, particularly pollinators. Most responses to nutrient addition were only apparent in plots without any large herbivores, suggesting that wild herbivores alone could already mitigate nutrient impacts. We also show that insects with contrasting feeding guilds may be favoured by fertilized, ungrazed conditions. Therefore, creating a mosaic of patches grazed at different intensities will enhance overall insect biodiversity.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"222 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140629544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lautaro L. Nasta, Paula E. Leva, Andrea C. Premoli, Martin R. Aguiar
Sexual reproduction, growth, and survival are crucial demographic strategies for plant population viability. Here, we propose a conceptual model predicting demographic responses of species based on their ecological strategy and the heterogeneity of environmental conditions within a biogeographical unit and then applied it to a case study from a 5˚ latitudinal gradient in the Patagonian steppes. We also aim to disentangle genetic from environmental effects on demographic responses. We performed in situ and common garden experiments with two species from six local populations of the Occidental Phytogeographical District of the Patagonian steppes. Species differ in key ecological traits, and thus fit into Grime's model for evolutionary strategies in plants: one as competitive species and the other as stress‐tolerant species. We calculated population growth rate (λ) and performed elasticity analyses to compare the contribution of each demographic strategy to population fitness between species and among local populations distributed along 600 km latitudinal gradient with differences in mean annual precipitation (MAP). We highlight four results. First, the competitive species change from sexual reproduction to growth as MAP increases. Second, the stress‐tolerant species relied on growth and survival along the MAP gradient. Third, interannual variation in resource availability modulated demographic responses for both strategies. Fourth, based on the comparison of the in situ and common garden experiments, we submit that demographic responses were genetically driven. Our study shows that demographic responses can be roughly predicted by the ecological strategy across environmental gradients. We show that differences arise not only between species, but also were genetically driven differences within species among local populations. Scaling up plant‐level responses to population‐level dynamics allows for a process‐based understanding of current and future biogeographical species organization. Furthermore, conservation and restoration efforts should be guided by demographic strategies underlying population viability.
{"title":"Extending Grime's CSR model to predict plant demographic responses across resource availability gradients: evidence from the patagonian steppes","authors":"Lautaro L. Nasta, Paula E. Leva, Andrea C. Premoli, Martin R. Aguiar","doi":"10.1111/oik.10203","DOIUrl":"https://doi.org/10.1111/oik.10203","url":null,"abstract":"Sexual reproduction, growth, and survival are crucial demographic strategies for plant population viability. Here, we propose a conceptual model predicting demographic responses of species based on their ecological strategy and the heterogeneity of environmental conditions within a biogeographical unit and then applied it to a case study from a 5˚ latitudinal gradient in the Patagonian steppes. We also aim to disentangle genetic from environmental effects on demographic responses. We performed in situ and common garden experiments with two species from six local populations of the Occidental Phytogeographical District of the Patagonian steppes. Species differ in key ecological traits, and thus fit into Grime's model for evolutionary strategies in plants: one as competitive species and the other as stress‐tolerant species. We calculated population growth rate (λ) and performed elasticity analyses to compare the contribution of each demographic strategy to population fitness between species and among local populations distributed along 600 km latitudinal gradient with differences in mean annual precipitation (MAP). We highlight four results. First, the competitive species change from sexual reproduction to growth as MAP increases. Second, the stress‐tolerant species relied on growth and survival along the MAP gradient. Third, interannual variation in resource availability modulated demographic responses for both strategies. Fourth, based on the comparison of the in situ and common garden experiments, we submit that demographic responses were genetically driven. Our study shows that demographic responses can be roughly predicted by the ecological strategy across environmental gradients. We show that differences arise not only between species, but also were genetically driven differences within species among local populations. Scaling up plant‐level responses to population‐level dynamics allows for a process‐based understanding of current and future biogeographical species organization. Furthermore, conservation and restoration efforts should be guided by demographic strategies underlying population viability.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"3 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lydia White, Nessa E. O'Connor, Abby Gilson, Ian Donohue
Simultaneous exposure to multiple stressors complicates the challenge of predicting ecological responses to global environmental change. Here, we show that the contributions of individual species and functional groups to the overall stability of ecosystems can be modified by the presence of different stressors, both individually and in combination. By disturbing natural rocky shore communities with nutrients and sediments and simulating extinction of predatory whelks and grazers, we also found that consumers can simultaneously stabilise and destabilise communities along different stability dimensions, irrespective of their trophic position. Our results suggest that our experimental disturbances influenced consumer contributions to stability indirectly by modifying the interactions between consumers and macroalgae in different ways. These findings merit further exploration in different systems exposed to a range of different stressors to better understand how perturbations of different kinds can modify the multifaceted contributions of species to the overall stability of ecosystems.
{"title":"Species contributions to ecosystem stability change with disturbance type","authors":"Lydia White, Nessa E. O'Connor, Abby Gilson, Ian Donohue","doi":"10.1111/oik.10077","DOIUrl":"https://doi.org/10.1111/oik.10077","url":null,"abstract":"Simultaneous exposure to multiple stressors complicates the challenge of predicting ecological responses to global environmental change. Here, we show that the contributions of individual species and functional groups to the overall stability of ecosystems can be modified by the presence of different stressors, both individually and in combination. By disturbing natural rocky shore communities with nutrients and sediments and simulating extinction of predatory whelks and grazers, we also found that consumers can simultaneously stabilise and destabilise communities along different stability dimensions, irrespective of their trophic position. Our results suggest that our experimental disturbances influenced consumer contributions to stability indirectly by modifying the interactions between consumers and macroalgae in different ways. These findings merit further exploration in different systems exposed to a range of different stressors to better understand how perturbations of different kinds can modify the multifaceted contributions of species to the overall stability of ecosystems.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"3 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Populations and ecological communities are changing worldwide, and empirical studies exhibit a mixture of either declining or mixed trends. Confusion in global biodiversity trends thus remains, while assessing such changes is of major social, political, and scientific importance. Part of this variability may arise from the difficulty to reliably assess global biodiversity trends. Here, we conducted a literature review of studies documenting the temporal dynamics of global biodiversity. We classified the differences among approaches, data, and methodology used by the reviewed papers to reveal common findings and sources of discrepancies. We show that reviews and meta‐analyses, along with the use of global indicators, are more likely to conclude that trends are declining. On the other hand, the longer the data are available, the more nuanced are the trends they generate. Our results also highlight the lack of studies providing information on the impact of synergistic pressures on a global scale, making it even more difficult to understand the driving factors of the observed changes and how to decide conservation plan accordingly. Finally, we stress the importance of taking into account the sources of confusion identified, as well as the complexity of biodiversity changes, in order to implement effective conservation strategies. In particular, biodiversity dynamics are almost systematically assumed to be linear, while non‐linear trends are largely neglected. Clarifying the sources of confusion in global biodiversity trends should strengthen large‐scale biodiversity monitoring and conservation.
{"title":"Sources of confusion in global biodiversity trends","authors":"Maëlys Boënnec, Vasilis Dakos, Vincent Devictor","doi":"10.1111/oik.10732","DOIUrl":"https://doi.org/10.1111/oik.10732","url":null,"abstract":"Populations and ecological communities are changing worldwide, and empirical studies exhibit a mixture of either declining or mixed trends. Confusion in global biodiversity trends thus remains, while assessing such changes is of major social, political, and scientific importance. Part of this variability may arise from the difficulty to reliably assess global biodiversity trends. Here, we conducted a literature review of studies documenting the temporal dynamics of global biodiversity. We classified the differences among approaches, data, and methodology used by the reviewed papers to reveal common findings and sources of discrepancies. We show that reviews and meta‐analyses, along with the use of global indicators, are more likely to conclude that trends are declining. On the other hand, the longer the data are available, the more nuanced are the trends they generate. Our results also highlight the lack of studies providing information on the impact of synergistic pressures on a global scale, making it even more difficult to understand the driving factors of the observed changes and how to decide conservation plan accordingly. Finally, we stress the importance of taking into account the sources of confusion identified, as well as the complexity of biodiversity changes, in order to implement effective conservation strategies. In particular, biodiversity dynamics are almost systematically assumed to be linear, while non‐linear trends are largely neglected. Clarifying the sources of confusion in global biodiversity trends should strengthen large‐scale biodiversity monitoring and conservation.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"46 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Humay Rahimova, Annika Neuhaus‐Harr, Mary V. Clancy, Yuan Guo, Robert R. Junker, Lina Ojeda‐Prieto, Hampus Petrén, Matthias Senft, Sharon E. Zytynska, Wolfgang W. Weisser, Robin Heinen, Jörg‐Peter Schnitzler
Intraspecific variation of specialized metabolites in plants, such as terpenoids, are used to determine chemotypes. Tansy Tanacetum vulgare exhibits diverse terpenoid profiles that affect insect communities. However, it is not fully known whether patterns of their chemical composition and associated insects vary beyond the community scale. Here, we investigated the geographic distribution of mono‐ and sesquiterpenoid chemotypes in tansy leaves and their relationships with specific insect communities across Germany. We sampled tansy leaves from ten plants with and five plants without aphids in each of 26 sites along a north–south and west–east transect in Germany. Hexane‐extracted metabolites from leaf tissues were analyzed by gas chromatography‐mass spectrometry (GC‐MS). Plant morphological traits, aphid occurrence and abundance, and occurrence of ants were recorded locally. The effect of plant chemotype, plant morphological parameters, and abiotic site parameters such as soil types, temperature and precipitation on insect occurrences were analyzed. Plants clustered into four monoterpenoid and four sesquiterpenoid chemotype classes. Monoterpene classes differed in their latitudinal distribution, whereas sesquiterpenes were more evenly distributed across the transect. Aphid and ant occurrence was influenced by monoterpenoids. Plants of monoterpenoid class 1 were colonized by aphids and ants significantly more often than expected by chance, whereas in other classes there were no significant differences. Aphid abundance was affected by soil type, and average annual temperature positively correlated with the occurrence of ants. We found significant geographic patterns in the distribution of tansy chemodiversity and show that monoterpenoids affect aphid and ant occurrence, while the soil type can influence aphid abundance. We show that geographic variation in plant chemistry influences insect community assembly on tansy plants.
{"title":"Geographic distribution of terpenoid chemotypes in Tanacetum vulgare mediates tansy aphid occurrence but not abundance","authors":"Humay Rahimova, Annika Neuhaus‐Harr, Mary V. Clancy, Yuan Guo, Robert R. Junker, Lina Ojeda‐Prieto, Hampus Petrén, Matthias Senft, Sharon E. Zytynska, Wolfgang W. Weisser, Robin Heinen, Jörg‐Peter Schnitzler","doi":"10.1111/oik.10320","DOIUrl":"https://doi.org/10.1111/oik.10320","url":null,"abstract":"Intraspecific variation of specialized metabolites in plants, such as terpenoids, are used to determine chemotypes. Tansy <jats:italic>Tanacetum vulgare</jats:italic> exhibits diverse terpenoid profiles that affect insect communities. However, it is not fully known whether patterns of their chemical composition and associated insects vary beyond the community scale. Here, we investigated the geographic distribution of mono‐ and sesquiterpenoid chemotypes in tansy leaves and their relationships with specific insect communities across Germany. We sampled tansy leaves from ten plants with and five plants without aphids in each of 26 sites along a north–south and west–east transect in Germany. Hexane‐extracted metabolites from leaf tissues were analyzed by gas chromatography‐mass spectrometry (GC‐MS). Plant morphological traits, aphid occurrence and abundance, and occurrence of ants were recorded locally. The effect of plant chemotype, plant morphological parameters, and abiotic site parameters such as soil types, temperature and precipitation on insect occurrences were analyzed. Plants clustered into four monoterpenoid and four sesquiterpenoid chemotype classes. Monoterpene classes differed in their latitudinal distribution, whereas sesquiterpenes were more evenly distributed across the transect. Aphid and ant occurrence was influenced by monoterpenoids. Plants of monoterpenoid class 1 were colonized by aphids and ants significantly more often than expected by chance, whereas in other classes there were no significant differences. Aphid abundance was affected by soil type, and average annual temperature positively correlated with the occurrence of ants. We found significant geographic patterns in the distribution of tansy chemodiversity and show that monoterpenoids affect aphid and ant occurrence, while the soil type can influence aphid abundance. We show that geographic variation in plant chemistry influences insect community assembly on tansy plants.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"36 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil organisms play a key role in carbon and nutrient cycling in forest ecosystems. While soil organisms are strongly influenced by litter chemistry and are highly sensitive to abiotic conditions, little is known about the interactive effects of these two factors. To address this gap in knowledge, we conducted a 10 week microcosm experiment in which we simulated the effects of climate change on soil ecology. More specifically, we studied relationships among litter nutrient concentration, microbial biomass, Collembola demographic parameters, and litter decomposition, exploring the potential impacts of increasing air temperature and decreasing soil moisture. To develop a gradient of nutrient concentrations, we created six tree litter mixtures with materials gathered from Quercus pubescens and its companion species. In contrast to microbes, we observed that Collembola abundance and litter decomposition were interactively affected by soil moisture and air temperature: the negative effect of increasing air temperature on Collembola abundance was amplified by reduced soil moisture, whereas the positive effect of increasing air temperature on litter decomposition disappeared under reduced soil moisture conditions. In contrast to fungi, the response of bacterial biomass and Collembola abundance to litter nutrient concentration was dependent on abiotic conditions. More specifically, the relationships between nutrients, especially calcium and magnesium, and bacterial biomass and Collembola abundance were less robust or disappeared under drier or warmer conditions. In conclusion, our findings underscore that ongoing climate change could affect soil organisms directly as well as indirectly, by altering their responses to litter nutrient concentrations. In addition, we found that nutrient‐rich habitats might be more affected than nutrient‐poor habitats by altered climatic conditions.
{"title":"Interactive effects of soil moisture, air temperature and litter nutrient diversity on soil microbial communities and Folsomia candida population","authors":"Charlotte Biryol, Adriane Aupic‐Samain, Caroline Lecareux, Thierry Gauquelin, Virginie Baldy, Mathieu Santonja","doi":"10.1111/oik.10345","DOIUrl":"https://doi.org/10.1111/oik.10345","url":null,"abstract":"Soil organisms play a key role in carbon and nutrient cycling in forest ecosystems. While soil organisms are strongly influenced by litter chemistry and are highly sensitive to abiotic conditions, little is known about the interactive effects of these two factors. To address this gap in knowledge, we conducted a 10 week microcosm experiment in which we simulated the effects of climate change on soil ecology. More specifically, we studied relationships among litter nutrient concentration, microbial biomass, Collembola demographic parameters, and litter decomposition, exploring the potential impacts of increasing air temperature and decreasing soil moisture. To develop a gradient of nutrient concentrations, we created six tree litter mixtures with materials gathered from <jats:italic>Quercus pubescens</jats:italic> and its companion species. In contrast to microbes, we observed that Collembola abundance and litter decomposition were interactively affected by soil moisture and air temperature: the negative effect of increasing air temperature on Collembola abundance was amplified by reduced soil moisture, whereas the positive effect of increasing air temperature on litter decomposition disappeared under reduced soil moisture conditions. In contrast to fungi, the response of bacterial biomass and Collembola abundance to litter nutrient concentration was dependent on abiotic conditions. More specifically, the relationships between nutrients, especially calcium and magnesium, and bacterial biomass and Collembola abundance were less robust or disappeared under drier or warmer conditions. In conclusion, our findings underscore that ongoing climate change could affect soil organisms directly as well as indirectly, by altering their responses to litter nutrient concentrations. In addition, we found that nutrient‐rich habitats might be more affected than nutrient‐poor habitats by altered climatic conditions.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"49 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ecological meta‐analyses usually exhibit high relative heterogeneity of effect size: most among‐study variation in effect size represents true variation in mean effect size, rather than sampling error. This heterogeneity arises from both methodological and ecological sources. Methodological heterogeneity is a nuisance that complicates the interpretation of data syntheses. One way to reduce methodological heterogeneity is via coordinated distributed experiments, in which investigators conduct the same experiment at different sites, using the same methods. We tested whether coordinated distributed experiments in ecology exhibit 1) low heterogeneity in effect size, and 2) lower heterogeneity than meta‐analyses, using data on 17 effects from eight coordinated distributed experiments, and 406 meta‐analyses. Consistent with our expectations, among‐site heterogeneity typically comprised <50% of the variance in effect size in distributed experiments. In contrast, heterogeneity within and among studies typically comprised >90% of the variance in effect size in meta‐analyses. However, this difference largely reflected the small size of most coordinated distributed experiments, and was no longer significant after controlling for size (number of studies or sites). These results are consistent with the hypothesis that methodological heterogeneity rarely comprises a substantial fraction of variance in effect size in ecology. We also conducted pairwise comparisons of absolute heterogeneity between coordinated distributed experiments and meta‐analyses on the same topics. Coordinated distributed experiments did not consistently exhibit lower absolute heterogeneity in effect size than meta‐analyses on the same topics. Our findings suggest that coordinated distributed experiments rarely increase uniformity of results by reducing methodological heterogeneity. Our results help refine the numerous distinct reasons for conducting coordinated distributed experiments.
{"title":"Coordinated distributed experiments in ecology do not consistently reduce heterogeneity in effect size","authors":"Julia Bebout, Jeremy W. Fox","doi":"10.1111/oik.10722","DOIUrl":"https://doi.org/10.1111/oik.10722","url":null,"abstract":"Ecological meta‐analyses usually exhibit high relative heterogeneity of effect size: most among‐study variation in effect size represents true variation in mean effect size, rather than sampling error. This heterogeneity arises from both methodological and ecological sources. Methodological heterogeneity is a nuisance that complicates the interpretation of data syntheses. One way to reduce methodological heterogeneity is via coordinated distributed experiments, in which investigators conduct the same experiment at different sites, using the same methods. We tested whether coordinated distributed experiments in ecology exhibit 1) low heterogeneity in effect size, and 2) lower heterogeneity than meta‐analyses, using data on 17 effects from eight coordinated distributed experiments, and 406 meta‐analyses. Consistent with our expectations, among‐site heterogeneity typically comprised <50% of the variance in effect size in distributed experiments. In contrast, heterogeneity within and among studies typically comprised >90% of the variance in effect size in meta‐analyses. However, this difference largely reflected the small size of most coordinated distributed experiments, and was no longer significant after controlling for size (number of studies or sites). These results are consistent with the hypothesis that methodological heterogeneity rarely comprises a substantial fraction of variance in effect size in ecology. We also conducted pairwise comparisons of absolute heterogeneity between coordinated distributed experiments and meta‐analyses on the same topics. Coordinated distributed experiments did not consistently exhibit lower absolute heterogeneity in effect size than meta‐analyses on the same topics. Our findings suggest that coordinated distributed experiments rarely increase uniformity of results by reducing methodological heterogeneity. Our results help refine the numerous distinct reasons for conducting coordinated distributed experiments.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"8 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matteo Luca Bastianelli, Christian von Hoermann, Katrin Kirchner, Johannes Signer, Claudia Dupke, Maik Henrich, Elodie Wielgus, Christian Fiderer, Elisa Belotti, Luděk Bufka, Simone Ciuti, Carsten F. Dormann, Tobias Kuemmerle, Ilse Storch, Clara Grilo, Marco Heurich
Roads can have diverse impacts on wildlife species, and while some species may adapt effectively, others may not. Studying multiple species' responses to the same infrastructure in a given area can help understand this variation and reveal the effects of disturbance on the ecology of wildlife communities. This study investigates the behavioural responses of four species with distinctive ecological and behavioural traits to roads in the protected Bohemian Forest Ecosystem in central Europe: European roe deer Capreolus capreolus, a solitary herbivore; red deer Cervus elaphus a gregarious herbivore; wild boar Sus scrofa, a gregarious omnivore and Eurasian lynx Lynx lynx, a solitary large carnivore. We used GPS data gathered from each species to study movement behaviour and habitat selection in relation to roads using an integrated step selection analysis. For all species and sexes, we predicted increased movement rates in response to roads, selection of vegetation cover near roads and open areas after road crossings, and increased road avoidance during the day. We found remarkably similar behavioural responses towards roads across species. The behavioural adaptations to road exposure, such as increased movement rates and selection for vegetation cover, were analogous to responses to natural predation risk. Roads were more strongly avoided during daytime, when traffic volume was high. Road crossings were more frequent at twilight and at night within open areas offering food resources. Gregarious animals exposed to roads favoured stronger road avoidance over faster movements. Ungulates crossed roads more at twilight, coinciding with commuter traffic during winter. Despite differences in the ecology and behaviour of the four species, our results showed similar adaptations towards a common threat. The continuous expansion of the global transportation network should be accompanied by efforts to understand and minimise the impact of roads on wildlife to assist wildlife management and ensure conservation.
{"title":"Risk response towards roads is consistent across multiple species in a temperate forest ecosystem","authors":"Matteo Luca Bastianelli, Christian von Hoermann, Katrin Kirchner, Johannes Signer, Claudia Dupke, Maik Henrich, Elodie Wielgus, Christian Fiderer, Elisa Belotti, Luděk Bufka, Simone Ciuti, Carsten F. Dormann, Tobias Kuemmerle, Ilse Storch, Clara Grilo, Marco Heurich","doi":"10.1111/oik.10433","DOIUrl":"https://doi.org/10.1111/oik.10433","url":null,"abstract":"Roads can have diverse impacts on wildlife species, and while some species may adapt effectively, others may not. Studying multiple species' responses to the same infrastructure in a given area can help understand this variation and reveal the effects of disturbance on the ecology of wildlife communities. This study investigates the behavioural responses of four species with distinctive ecological and behavioural traits to roads in the protected Bohemian Forest Ecosystem in central Europe: European roe deer <jats:italic>Capreolus capreolus</jats:italic>, a solitary herbivore; red deer <jats:italic>Cervus elaphus</jats:italic> a gregarious herbivore; wild boar <jats:italic>Sus scrofa</jats:italic>, a gregarious omnivore and Eurasian lynx <jats:italic>Lynx lynx</jats:italic>, a solitary large carnivore. We used GPS data gathered from each species to study movement behaviour and habitat selection in relation to roads using an integrated step selection analysis. For all species and sexes, we predicted increased movement rates in response to roads, selection of vegetation cover near roads and open areas after road crossings, and increased road avoidance during the day. We found remarkably similar behavioural responses towards roads across species. The behavioural adaptations to road exposure, such as increased movement rates and selection for vegetation cover, were analogous to responses to natural predation risk. Roads were more strongly avoided during daytime, when traffic volume was high. Road crossings were more frequent at twilight and at night within open areas offering food resources. Gregarious animals exposed to roads favoured stronger road avoidance over faster movements. Ungulates crossed roads more at twilight, coinciding with commuter traffic during winter. Despite differences in the ecology and behaviour of the four species, our results showed similar adaptations towards a common threat. The continuous expansion of the global transportation network should be accompanied by efforts to understand and minimise the impact of roads on wildlife to assist wildlife management and ensure conservation.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"37 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gabriela Quiroga, Bastien Castagneyrol, Luis Abdala‐Roberts, Xoaquín Moreira
The abiotic environment exerts strong effects on plant‐associated microbes, shaping their interactions with plants and resulting ecosystem processes. However, these abiotic effects on plant–microbe interactions are often highly specific and contingent on the abiotic driver or microbial group, requiring synthesis work describing general patterns and from this generate hypotheses and guide mechanistic work. To address this, we conducted a meta‐analysis of the effects of climate change‐related abiotic factors, namely warming, drought, and eCO2, on plant‐associated microbes distinguishing by microbial taxonomic or biological group (bacteria, fungi or virus) and the plant part where microbes are found or associated with (phyllosphere or rhizosphere). We found abiotic driver‐specific patterns, whereby drought significantly reduced microbial abundance, whereas warming and eCO2 had no significant effects. In addition, these abiotic effects were contingent on the microbial taxonomic group, with fungi being negatively affected by drought but positively affected by warming (eCO2 enrichment had no effect), whereas bacteria and viruses were not significantly affected by any factor. Likewise, rhizospheric microbes were negatively affected by drought but positively affected by warming (eCO2 enrichment had no effect), whereas phyllospheric microbes were not significantly affected by any factor. Collectively, these findings point to important implications for global change research by highlighting contrasting effects of climate change‐related abiotic drivers on plant‐associated microbes and the contingency of such effects on microbe life histories and the nature of their interactions with plants.
{"title":"A meta‐analysis of the effects of climate change‐related abiotic factors on aboveground and belowground plant‐associated microbes","authors":"Gabriela Quiroga, Bastien Castagneyrol, Luis Abdala‐Roberts, Xoaquín Moreira","doi":"10.1111/oik.10411","DOIUrl":"https://doi.org/10.1111/oik.10411","url":null,"abstract":"The abiotic environment exerts strong effects on plant‐associated microbes, shaping their interactions with plants and resulting ecosystem processes. However, these abiotic effects on plant–microbe interactions are often highly specific and contingent on the abiotic driver or microbial group, requiring synthesis work describing general patterns and from this generate hypotheses and guide mechanistic work. To address this, we conducted a meta‐analysis of the effects of climate change‐related abiotic factors, namely warming, drought, and eCO<jats:sub>2</jats:sub>, on plant‐associated microbes distinguishing by microbial taxonomic or biological group (bacteria, fungi or virus) and the plant part where microbes are found or associated with (phyllosphere or rhizosphere). We found abiotic driver‐specific patterns, whereby drought significantly reduced microbial abundance, whereas warming and eCO<jats:sub>2</jats:sub> had no significant effects. In addition, these abiotic effects were contingent on the microbial taxonomic group, with fungi being negatively affected by drought but positively affected by warming (eCO<jats:sub>2</jats:sub> enrichment had no effect), whereas bacteria and viruses were not significantly affected by any factor. Likewise, rhizospheric microbes were negatively affected by drought but positively affected by warming (eCO<jats:sub>2</jats:sub> enrichment had no effect), whereas phyllospheric microbes were not significantly affected by any factor. Collectively, these findings point to important implications for global change research by highlighting contrasting effects of climate change‐related abiotic drivers on plant‐associated microbes and the contingency of such effects on microbe life histories and the nature of their interactions with plants.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"107 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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