Théo Bodineau, Chloé Chabaud, Beatriz Decencière, Simon Agostini, Olivier Lourdais, Sandrine Meylan, Jean‐François Le Galliard
The regulation of energy, water and thermal balance involves integrated processes that should drive ecological responses of ectotherms to climate change. Functional tradeoffs between thermoregulation and hydroregulation are exacerbated during hot or dry spells, but how microhabitat hydric properties and trophic resource availability influence these tradeoffs remains unknown. Here, we investigated the effects of microhabitat humidity and food availability on thermo‐hydroregulation strategies in the ground‐dwelling common lizard Zootoca vivipara during a simulated hot and dry spell event. We exposed lizards to a five‐day long acute water restriction in hot conditions in the laboratory and manipulated hydric quality of the retreat site (wet or dry shelter) as well as food availability (ad libitum food or food deprivation). Water restriction and food deprivation caused physiological responses such as muscle catabolism and mobilization of caudal energy reserves. Lizards also developed behavioural strategies to conserve water or energy via decreased thermoregulation effort, higher shelter use and increased eye closure behaviours through time. These physiological and behavioural changes were importantly buffered by the presence of a wet shelter but not by food availability. A wet retreat site reduced the behavioural conflicts between thermoregulation and hydroregulation, allowed lizards to maintain a better condition and reduced physiological dehydration. Instead, food intake did not play a major role in the regulation of hydration state and increased behavioural conflicts between thermoregulation and hydroregulation. A better consideration of thermo‐hydroregulation behaviours and microhabitat hydric quality is required to address ectotherm responses to future climate change.
{"title":"Microhabitat humidity rather than food availability drives thermo‐hydroregulation responses to drought in a lizard","authors":"Théo Bodineau, Chloé Chabaud, Beatriz Decencière, Simon Agostini, Olivier Lourdais, Sandrine Meylan, Jean‐François Le Galliard","doi":"10.1111/oik.10535","DOIUrl":"https://doi.org/10.1111/oik.10535","url":null,"abstract":"The regulation of energy, water and thermal balance involves integrated processes that should drive ecological responses of ectotherms to climate change. Functional tradeoffs between thermoregulation and hydroregulation are exacerbated during hot or dry spells, but how microhabitat hydric properties and trophic resource availability influence these tradeoffs remains unknown. Here, we investigated the effects of microhabitat humidity and food availability on thermo‐hydroregulation strategies in the ground‐dwelling common lizard <jats:italic>Zootoca vivipara</jats:italic> during a simulated hot and dry spell event. We exposed lizards to a five‐day long acute water restriction in hot conditions in the laboratory and manipulated hydric quality of the retreat site (wet or dry shelter) as well as food availability (ad libitum food or food deprivation). Water restriction and food deprivation caused physiological responses such as muscle catabolism and mobilization of caudal energy reserves. Lizards also developed behavioural strategies to conserve water or energy via decreased thermoregulation effort, higher shelter use and increased eye closure behaviours through time. These physiological and behavioural changes were importantly buffered by the presence of a wet shelter but not by food availability. A wet retreat site reduced the behavioural conflicts between thermoregulation and hydroregulation, allowed lizards to maintain a better condition and reduced physiological dehydration. Instead, food intake did not play a major role in the regulation of hydration state and increased behavioural conflicts between thermoregulation and hydroregulation. A better consideration of thermo‐hydroregulation behaviours and microhabitat hydric quality is required to address ectotherm responses to future climate change.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"17 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574385","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}
Alfonso Allen‐Perkins, María Hurtado, David García‐Callejas, Oscar Godoy, Ignasi Bartomeus
Interaction networks are a widely used tool to understand the dynamics of plant–pollinator ecological communities. However, while most mutualistic networks have been defined at the species level, ecological processes such as pollination take place at different scales, including the individual or patch levels. Yet, current approaches studying fine‐grain sub‐specific plant–pollinator networks only account for interactions among nodes belonging to a single plant species due to the conceptual and mathematical limitations of modeling simultaneously several plant species each composed of several nodes. Here, we introduce a multilayer diffusion network framework that allows modeling simple diffusion processes between nodes pertaining to the same or different layers (i.e. species). It is designed to depict from the network structure the potential conspecific and heterospecific pollen flows among plant individuals or patches. This potential pollen flow is modeled as a transport‐like system, in which pollen grain movements are represented as random‐walkers that diffuse on an ensemble of bipartite layers of conspecific plants and their shared pollinators. We exemplify this physical conceptualization using a dataset of nine fine‐grain sub‐specific plant–pollinator networks from a Mediterranean grassland of annual plants, where plant nodes represent groups of conspecifics within patches of 1 m2. The diffusion networks show pollinators effectively connecting sets of patches of the same and different plant species, forming a modular structure. Interestingly, different properties of the network structure, such as the conspecific pollen arrival probability and the number of conspecific subgraphs in which plants are embedded, are critical for the seed production of different plant species. We provide a simple but robust set of metrics to calculate potential pollen flow and scale down network ecology to functioning properties at the individual or patch level, where most ecological processes take place, hence moving forward the description and interpretation of species‐rich communities across scales.
{"title":"Multilayer diffusion networks as a tool to assess the structure and functioning of fine grain sub‐specific plant–pollinator networks","authors":"Alfonso Allen‐Perkins, María Hurtado, David García‐Callejas, Oscar Godoy, Ignasi Bartomeus","doi":"10.1111/oik.10168","DOIUrl":"https://doi.org/10.1111/oik.10168","url":null,"abstract":"Interaction networks are a widely used tool to understand the dynamics of plant–pollinator ecological communities. However, while most mutualistic networks have been defined at the species level, ecological processes such as pollination take place at different scales, including the individual or patch levels. Yet, current approaches studying fine‐grain sub‐specific plant–pollinator networks only account for interactions among nodes belonging to a single plant species due to the conceptual and mathematical limitations of modeling simultaneously several plant species each composed of several nodes. Here, we introduce a multilayer diffusion network framework that allows modeling simple diffusion processes between nodes pertaining to the same or different layers (i.e. species). It is designed to depict from the network structure the potential conspecific and heterospecific pollen flows among plant individuals or patches. This potential pollen flow is modeled as a transport‐like system, in which pollen grain movements are represented as random‐walkers that diffuse on an ensemble of bipartite layers of conspecific plants and their shared pollinators. We exemplify this physical conceptualization using a dataset of nine fine‐grain sub‐specific plant–pollinator networks from a Mediterranean grassland of annual plants, where plant nodes represent groups of conspecifics within patches of 1 m<jats:sup>2</jats:sup>. The diffusion networks show pollinators effectively connecting sets of patches of the same and different plant species, forming a modular structure. Interestingly, different properties of the network structure, such as the conspecific pollen arrival probability and the number of conspecific subgraphs in which plants are embedded, are critical for the seed production of different plant species. We provide a simple but robust set of metrics to calculate potential pollen flow and scale down network ecology to functioning properties at the individual or patch level, where most ecological processes take place, hence moving forward the description and interpretation of species‐rich communities across scales.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"1 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573813","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}
Joshua P. Twining, Jennifer L. Brazeal, Paul G. Jensen, Angela K. Fuller
The widespread eradication of large carnivores and subsequent expansion of top mesopredators has the potential to impact species and community interactions with ecosystem‐wide implications. An example of these trophic dynamics is the widespread establishment of coyotes following extirpation of wolves and mountain lions in eastern North America. Here, we examined occupancy of three carnivores in northern New York considering both environmental/habitat factors and interspecific interactions. We estimated the co‐occurrence of coyotes, fishers, and martens from a landscape‐scale winter camera trap survey repeated annually for three years. Martens occurred independently of both coyotes and fishers, while fishers and coyotes displayed positive intraguild interactions that were constant across the landscape. Both marten and fisher first‐order occupancy were driven by a combination of biotic and abiotic factors, with both species displaying positive associations with forest cover but antithetical responses to average snow depth. The integral and antithetical role of snow depth in driving the occurrence of martens (positive) and fishers (negative) in the landscape indicates that future climatic warming could reduce the availability of current spatial refuges for martens created by severe winter conditions. Climate‐driven alterations to established competitive interactions and co‐existence patterns between marten and fisher have critical implications for the species survival and conservation. We provide correlational evidence consistent with the potential for positive top‐down effects of dominant mesocarnivores on subordinate species, with fisher occupancy increasing conditional on the presence of coyotes across the landscape. These findings align with the hypothesis that under certain conditions, coyotes may facilitate certain subordinate carnivores. The evidence produced here is consistent with hypotheses on the dynamic nature of trophic niches. We demonstrate the need to consider the interplay between climate, habitat, and interspecific interactions to understand wildlife occupancy patterns and inform wildlife management in a rapidly changing world.
{"title":"Intraguild interactions and abiotic conditions mediate occupancy of mammalian carnivores: co‐occurrence of coyotes–fishers–martens","authors":"Joshua P. Twining, Jennifer L. Brazeal, Paul G. Jensen, Angela K. Fuller","doi":"10.1111/oik.10577","DOIUrl":"https://doi.org/10.1111/oik.10577","url":null,"abstract":"The widespread eradication of large carnivores and subsequent expansion of top mesopredators has the potential to impact species and community interactions with ecosystem‐wide implications. An example of these trophic dynamics is the widespread establishment of coyotes following extirpation of wolves and mountain lions in eastern North America. Here, we examined occupancy of three carnivores in northern New York considering both environmental/habitat factors and interspecific interactions. We estimated the co‐occurrence of coyotes, fishers, and martens from a landscape‐scale winter camera trap survey repeated annually for three years. Martens occurred independently of both coyotes and fishers, while fishers and coyotes displayed positive intraguild interactions that were constant across the landscape. Both marten and fisher first‐order occupancy were driven by a combination of biotic and abiotic factors, with both species displaying positive associations with forest cover but antithetical responses to average snow depth. The integral and antithetical role of snow depth in driving the occurrence of martens (positive) and fishers (negative) in the landscape indicates that future climatic warming could reduce the availability of current spatial refuges for martens created by severe winter conditions. Climate‐driven alterations to established competitive interactions and co‐existence patterns between marten and fisher have critical implications for the species survival and conservation. We provide correlational evidence consistent with the potential for positive top‐down effects of dominant mesocarnivores on subordinate species, with fisher occupancy increasing conditional on the presence of coyotes across the landscape. These findings align with the hypothesis that under certain conditions, coyotes may facilitate certain subordinate carnivores. The evidence produced here is consistent with hypotheses on the dynamic nature of trophic niches. We demonstrate the need to consider the interplay between climate, habitat, and interspecific interactions to understand wildlife occupancy patterns and inform wildlife management in a rapidly changing world.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"9 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140205318","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}
Mark Westoby, Samuel C. Andrew, Rachael V. Gallagher, Julian Schrader
With climate zones moving poleward, it is interesting to know how rapidly species are gained and lost along temperature gradients. For the Australian native vascular flora, observed climate envelopes for species distributions have here been calculated from data for occurrence at geographical locations. For each degree temperature increase along a continental temperature gradient, numbers of species crossing their cold boundary and hence added to the flora, and crossing their warm boundary and hence lost to the flora, were counted. These counts of gains and losses were expressed as percentages of the flora recorded as present at that temperature. We report results for the flora at > 700 mm rainfall pa along the Australian east coast, where higher rainfall is continuously distributed throughout the latitudinal range. Per °C mean annual temperature increase, 20 ± 11% (mean ± SD) of species were gained, and 14 ± 4% were lost, across the range 9–23°C. Many further questions arise. For example, which other continental floras might show faster or slower rates of species gain and loss along temperature gradients? Similarly, might species with particular traits show faster rates of turnover: for example, species with local dispersal such as those with diaspore morphologies adapted for ants, compared to those adapted for bird dispersal?
{"title":"Species gain and loss per degree Celsius","authors":"Mark Westoby, Samuel C. Andrew, Rachael V. Gallagher, Julian Schrader","doi":"10.1111/oik.10556","DOIUrl":"https://doi.org/10.1111/oik.10556","url":null,"abstract":"With climate zones moving poleward, it is interesting to know how rapidly species are gained and lost along temperature gradients. For the Australian native vascular flora, observed climate envelopes for species distributions have here been calculated from data for occurrence at geographical locations. For each degree temperature increase along a continental temperature gradient, numbers of species crossing their cold boundary and hence added to the flora, and crossing their warm boundary and hence lost to the flora, were counted. These counts of gains and losses were expressed as percentages of the flora recorded as present at that temperature. We report results for the flora at > 700 mm rainfall pa along the Australian east coast, where higher rainfall is continuously distributed throughout the latitudinal range. Per °C mean annual temperature increase, 20 ± 11% (mean ± SD) of species were gained, and 14 ± 4% were lost, across the range 9–23°C. Many further questions arise. For example, which other continental floras might show faster or slower rates of species gain and loss along temperature gradients? Similarly, might species with particular traits show faster rates of turnover: for example, species with local dispersal such as those with diaspore morphologies adapted for ants, compared to those adapted for bird dispersal?","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"14 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124516","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}
Ecosystem functions greatly depend on trophic interactions between consumers and their resources. Resource consumption depends on ingestion, digestion, and allocation processes. Mechanical constraints are expected to influence ingestion, while metabolic and nutritional constraints are expected to influence allocation. Leaf litter are resources presenting a high mechanical and nutritional heterogeneity that depends on plant identity and on physical and microbial processing over the course of decomposition. Litter consumption by detritivores is known to depend on metabolic and nutritional constraints but the importance of mechanical constraints is yet unknown. After accounting for metabolic constraints on consumption rate, we tested the relative importance of mechanical and nutritional constraints in explaining litter consumption rates by detritivores. For this, we exposed 16 leaf treatments (eight leaf species either just leached or leached and microbially conditioned) to four aquatic and five terrestrial detritivore taxa in laboratory no‐choice consumption experiments. We investigated two mechanical constraints: grabbing and fragmenting the resource, by measuring suitable couples of mechanical traits for both litter and detritivores. We also investigated four nutritional constraints related to N, P, K and Ca contents in both detritivores and litter. For each constraint, we also tested if trait matching significantly contribute to explain consumption. Our analysis revealed that both mechanical and nutritional constraints are influencing mass‐independent consumption rate but that mechanical constraints predominate over nutritional constraints. Litter fragmentation, studied through litter toughness and detritivore biting force, was especially important to explain consumption rate. Nutritional constraints were dominated by P constraints. Trait‐matching had very weak importance and was significant only for P constraints. Our findings highlight the importance of mechanical constraints for litter consumption by detritivores.
{"title":"Litter consumption by macrodetritivores depends more on mechanical than on nutritional constraints","authors":"Théo Marchand, Lola Estabes, Benjamin Pey","doi":"10.1111/oik.10280","DOIUrl":"https://doi.org/10.1111/oik.10280","url":null,"abstract":"Ecosystem functions greatly depend on trophic interactions between consumers and their resources. Resource consumption depends on ingestion, digestion, and allocation processes. Mechanical constraints are expected to influence ingestion, while metabolic and nutritional constraints are expected to influence allocation. Leaf litter are resources presenting a high mechanical and nutritional heterogeneity that depends on plant identity and on physical and microbial processing over the course of decomposition. Litter consumption by detritivores is known to depend on metabolic and nutritional constraints but the importance of mechanical constraints is yet unknown. After accounting for metabolic constraints on consumption rate, we tested the relative importance of mechanical and nutritional constraints in explaining litter consumption rates by detritivores. For this, we exposed 16 leaf treatments (eight leaf species either just leached or leached and microbially conditioned) to four aquatic and five terrestrial detritivore taxa in laboratory no‐choice consumption experiments. We investigated two mechanical constraints: grabbing and fragmenting the resource, by measuring suitable couples of mechanical traits for both litter and detritivores. We also investigated four nutritional constraints related to N, P, K and Ca contents in both detritivores and litter. For each constraint, we also tested if trait matching significantly contribute to explain consumption. Our analysis revealed that both mechanical and nutritional constraints are influencing mass‐independent consumption rate but that mechanical constraints predominate over nutritional constraints. Litter fragmentation, studied through litter toughness and detritivore biting force, was especially important to explain consumption rate. Nutritional constraints were dominated by P constraints. Trait‐matching had very weak importance and was significant only for P constraints. Our findings highlight the importance of mechanical constraints for litter consumption by detritivores.<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/oik13702-math-0004.png\" xlink:title=\"urn:x-wiley:00301299:media:oik13702:oik13702-math-0004\" />","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"67 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124520","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}
David Bogdanski, Lorena Marcos‐Almansa, Augusto A. V. Flores
Species that form complex biogenic structures may increase niche space for many others and are assumed to be paramount for whole‐assemblage stability and ecosystem functioning. Because they often ameliorate physical conditions, ecosystem engineering species are also predicted to become more important with environmental stress. Testing this hypothesis, however, has proven difficult because isolating facilitation effects along the entire stress gradient is challenging. Here we addressed motile invertebrate assemblages associated to the mid‐intertidal chthamalid barnacle cover at four rocky shores, either with (‘facilitated') or without (‘control') a secondary natural cover of small mussels (Mytilaster solisianus and Brachidontes darwinianus). Following a factorial balanced design, replicate samples were taken at three tidal heights in all sites, encompassing a clear gradient of thermal stress and desiccation potential along the vertical range of the mussel‐enriched zone. While observations on general abundance were mostly consistent with stress‐independent facilitation, results for richness, diversity and assemblage structure indicated overarching stress‐dependent responses. All these later three response variables steadily declined from the low to the high level in the control barnacle habitat but remained unaltered in the mussel‐facilitated habitat. Increased facilitation higher on the shore is mostly due to retention of stress‐vulnerable groups such as polychaetes, flatworms and large nematodes which virtually collapse in the higher control habitat, further indicating that mechanisms of mussel facilitation involve relief of environmental stress rather than protection from higher‐order consumers. Our results suggest that mussel ecosystem engineering was fully preserved during the summer season when sampling took place. Ongoing research simulating heat waves compatible to climate‐change scenarios will test whether mussel facilitation would hold over the coming decades.
{"title":"Intertidal mussels as ecosystem engineers: maintenance of invertebrate assemblages amid intertidal stress gradients","authors":"David Bogdanski, Lorena Marcos‐Almansa, Augusto A. V. Flores","doi":"10.1111/oik.10304","DOIUrl":"https://doi.org/10.1111/oik.10304","url":null,"abstract":"Species that form complex biogenic structures may increase niche space for many others and are assumed to be paramount for whole‐assemblage stability and ecosystem functioning. Because they often ameliorate physical conditions, ecosystem engineering species are also predicted to become more important with environmental stress. Testing this hypothesis, however, has proven difficult because isolating facilitation effects along the entire stress gradient is challenging. Here we addressed motile invertebrate assemblages associated to the mid‐intertidal chthamalid barnacle cover at four rocky shores, either with (‘facilitated') or without (‘control') a secondary natural cover of small mussels (<jats:italic>Mytilaster solisianus</jats:italic> and <jats:italic>Brachidontes darwinianus</jats:italic>). Following a factorial balanced design, replicate samples were taken at three tidal heights in all sites, encompassing a clear gradient of thermal stress and desiccation potential along the vertical range of the mussel‐enriched zone. While observations on general abundance were mostly consistent with stress‐independent facilitation, results for richness, diversity and assemblage structure indicated overarching stress‐dependent responses. All these later three response variables steadily declined from the low to the high level in the control barnacle habitat but remained unaltered in the mussel‐facilitated habitat. Increased facilitation higher on the shore is mostly due to retention of stress‐vulnerable groups such as polychaetes, flatworms and large nematodes which virtually collapse in the higher control habitat, further indicating that mechanisms of mussel facilitation involve relief of environmental stress rather than protection from higher‐order consumers. Our results suggest that mussel ecosystem engineering was fully preserved during the summer season when sampling took place. Ongoing research simulating heat waves compatible to climate‐change scenarios will test whether mussel facilitation would hold over the coming decades.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"24 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124402","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}
Roswitha Schmickl, Mario Vallejo Marín, Jakub Hojka, Juan Manuel Gorospe, Mohammad Javad Haghighatnia, Ömer İltaş, Adam Kantor, Marek Slovák, Clément Lafon Placette
The paradox between the ubiquity of polyploid lineages in plants and the early obstacles to the establishment of polyploids is a long‐studied yet unresolved question in evolutionary biology. It is assumed that to successfully persist after emergence, newly formed polyploids need to display certain fitness advantages and show a certain extent of reproductive isolation with their diploid progenitors. In this study, we tested whether immediate floral changes following polyploidization can improve pollinator visitation and enable pollinator preference leading to assortative mating, i.e. build a premating reproductive barrier between diploids and polyploids. For this purpose, we generated synthetic tetraploids of Arabidopsis arenosa and measured insect visitor behavior on diploids and synthetic tetraploids. We found that the increased floral size that accompanied polyploidization did not lead to a measurable increase in visitor preference, with insects visiting diploid and tetraploid plants at equal frequency. Despite this observation, tetraploids set more fruits than diploids, suggesting a positive impact of polyploidization on pollen transfer via other means. In addition, polyploidization did not lead to assortative mating but instead promoted interploidy pollen exchange, since visitors preferentially switched between cytotypes rather than preferring one. Consistent with this switching behavior, most of the progeny from tetraploid plants were triploid. Our data suggest that polyploidization has an immediate impact on mating in plants, but in a more complex way than has been assumed previously.
{"title":"Polyploidy‐induced floral changes lead to unexpected pollinator behavior in Arabidopsis arenosa","authors":"Roswitha Schmickl, Mario Vallejo Marín, Jakub Hojka, Juan Manuel Gorospe, Mohammad Javad Haghighatnia, Ömer İltaş, Adam Kantor, Marek Slovák, Clément Lafon Placette","doi":"10.1111/oik.10267","DOIUrl":"https://doi.org/10.1111/oik.10267","url":null,"abstract":"The paradox between the ubiquity of polyploid lineages in plants and the early obstacles to the establishment of polyploids is a long‐studied yet unresolved question in evolutionary biology. It is assumed that to successfully persist after emergence, newly formed polyploids need to display certain fitness advantages and show a certain extent of reproductive isolation with their diploid progenitors. In this study, we tested whether immediate floral changes following polyploidization can improve pollinator visitation and enable pollinator preference leading to assortative mating, i.e. build a premating reproductive barrier between diploids and polyploids. For this purpose, we generated synthetic tetraploids of <jats:italic>Arabidopsis arenosa</jats:italic> and measured insect visitor behavior on diploids and synthetic tetraploids. We found that the increased floral size that accompanied polyploidization did not lead to a measurable increase in visitor preference, with insects visiting diploid and tetraploid plants at equal frequency. Despite this observation, tetraploids set more fruits than diploids, suggesting a positive impact of polyploidization on pollen transfer via other means. In addition, polyploidization did not lead to assortative mating but instead promoted interploidy pollen exchange, since visitors preferentially switched between cytotypes rather than preferring one. Consistent with this switching behavior, most of the progeny from tetraploid plants were triploid. Our data suggest that polyploidization has an immediate impact on mating in plants, but in a more complex way than has been assumed previously.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"68 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140129834","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}
Morgan D. T. Frost, Kimberly J. Komatsu, Lauren M. Porensky, Kurt O. Reinhart, Kevin R. Wilcox, Zachary L. T. Bunch, Ashley D. Jolin, Katielyn A. Johnston, Gracen E. Trimas, Sally E. Koerner
Species interactions shape native plant communities, influencing both composition and ecosystem processes, with invasion by non‐native species threatening these dynamic relationships, native species, and function. The consequences of invasive plants in particular may stretch across taxa to impact plant, insect, and soil microbial communities directly and indirectly, with consequences for ecological functioning. In northern mixed‐grass prairies in the United States, invasion by two annual brome grasses, Bromus arvensis and B. tectorum, negatively impacts rangeland plants; however, the simultaneous effects on insects and soil microbes (bacteria and archaea), and the implications for ecological function, have received less attention. Here, using observational field studies conducted at two mixed‐grass prairie sites in Montana and Wyoming, we assessed the relationships between plants, insects, and soil microbes across gradients of invasion by B. arvensis and B. tectorum. Overall, we found differences in plant and insect communities and functional groups with increasing invasion abundance for both brome species. However, associations between invasion and the soil microbial community were species specific, as we only saw these relationships under B. tectorum invasion, implying B. tectorum may have more substantial consequences for rangeland management. While invasion by annual bromes may cause changes in certain plant and insect functional groups, such as C4 perennial grasses and certain insect herbivores, soil microbial functional groups may be less impacted, especially under B. arvensis invasion. This work sheds light on the need to explore changes in natural communities across taxa and to all invasive species, as ecosystem effects are likely to be contingent upon both.
物种间的相互作用塑造了本地植物群落，影响着其组成和生态系统过程，而非本地物种的入侵则威胁着这些动态关系、本地物种和功能。特别是入侵植物的后果可能会延伸到各个类群，直接或间接地影响植物、昆虫和土壤微生物群落，从而对生态功能造成影响。在美国北部混合草草原，两种一年生锦鸡儿草（Bromus arvensis 和 B. tectorum）的入侵对牧场植物产生了负面影响；然而，同时对昆虫和土壤微生物（细菌和古细菌）产生的影响以及对生态功能的影响却较少受到关注。在这里，我们利用在蒙大拿州和怀俄明州的两个混合草草原地点进行的野外观察研究，评估了在 B. arvensis 和 B. tectorum 入侵梯度上植物、昆虫和土壤微生物之间的关系。总体而言，我们发现随着入侵丰度的增加，这两种锦鸡儿属植物和昆虫群落及功能群之间存在差异。然而，入侵与土壤微生物群落之间的关系是有物种特异性的，因为我们只在 B. tectorum 入侵的情况下看到了这些关系，这意味着 B. tectorum 可能会对牧场管理产生更大的影响。虽然一年生草本植物的入侵可能会导致某些植物和昆虫功能群的变化，如 C4 多年生禾本科植物和某些昆虫食草动物，但土壤微生物功能群受到的影响可能较小，尤其是在 B. arvensis 入侵的情况下。这项研究揭示了探索不同类群的自然群落变化以及所有入侵物种变化的必要性，因为生态系统的影响可能取决于这两方面。
{"title":"Plant, insect, and soil microbial communities vary across brome invasion gradients in northern mixed‐grass prairies","authors":"Morgan D. T. Frost, Kimberly J. Komatsu, Lauren M. Porensky, Kurt O. Reinhart, Kevin R. Wilcox, Zachary L. T. Bunch, Ashley D. Jolin, Katielyn A. Johnston, Gracen E. Trimas, Sally E. Koerner","doi":"10.1111/oik.10515","DOIUrl":"https://doi.org/10.1111/oik.10515","url":null,"abstract":"Species interactions shape native plant communities, influencing both composition and ecosystem processes, with invasion by non‐native species threatening these dynamic relationships, native species, and function. The consequences of invasive plants in particular may stretch across taxa to impact plant, insect, and soil microbial communities directly and indirectly, with consequences for ecological functioning. In northern mixed‐grass prairies in the United States, invasion by two annual brome grasses, <jats:italic>Bromus arvensis</jats:italic> and <jats:italic>B. tectorum</jats:italic>, negatively impacts rangeland plants; however, the simultaneous effects on insects and soil microbes (bacteria and archaea), and the implications for ecological function, have received less attention. Here, using observational field studies conducted at two mixed‐grass prairie sites in Montana and Wyoming, we assessed the relationships between plants, insects, and soil microbes across gradients of invasion by <jats:italic>B. arvensis</jats:italic> and <jats:italic>B. tectorum</jats:italic>. Overall, we found differences in plant and insect communities and functional groups with increasing invasion abundance for both brome species. However, associations between invasion and the soil microbial community were species specific, as we only saw these relationships under <jats:italic>B. tectorum</jats:italic> invasion, implying <jats:italic>B. tectorum</jats:italic> may have more substantial consequences for rangeland management. While invasion by annual bromes may cause changes in certain plant and insect functional groups, such as C<jats:sub>4</jats:sub> perennial grasses and certain insect herbivores, soil microbial functional groups may be less impacted, especially under <jats:italic>B. arvensis</jats:italic> invasion. This work sheds light on the need to explore changes in natural communities across taxa and to all invasive species, as ecosystem effects are likely to be contingent upon both.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"62 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140070577","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}
Tomonari Matsuo, Frans Bongers, Miguel Martínez-Ramos, Masha T. van der Sande, Lourens Poorter
In closed-canopy systems globally, plants exhibit intense competition for light, prioritizing vertical growth to attain elevated positions within the canopy. Light competition is especially intense in tropical rainforests because of their dense shaded stands, and during forest succession because of concomitant changes in vertical light profiles. We evaluated how the height growth of individual tree differs among forest light strata (canopy, sub-canopy and understorey) and successional guilds (early, mid- and late successional species) during secondary succession in a Mexican rainforest. Fourteen secondary forest stands differing in time since agricultural abandonment (1–25 years) were monitored for seven consecutive years. For each stand and census year we estimated relative light intensity (RLI) for each height and categorized trees into forest light strata: understorey (RLI ≦ 33.3%), sub-canopy (33.3% ≦ RLI ≦ 66.6%) and canopy (RLI ≧ 66.6%), and into successional guilds based on the literature. We estimated two measures of height growth: absolute height growth (HGabs, cm year−1) calculated as the difference in tree height between two consecutive censuses, and biomass partitioning to height growth (HGbp, in kg kg−1 × 100) calculated as the percentage of total aboveground biomass growth partitioned to height growth. Earlier in succession, trees for all strata had greater HGabs and HGbp, resulting in rapid vertical forest development. HGabs was fastest for canopy trees, followed by sub-canopy and understorey trees. These differences in HGabs among strata, combined with their inter-specific variation and continuous recruitment of small individuals, lead to a rapid differentiation in tree sizes and increase stand structural heterogeneity. HGbp was greater for understorey and sub-canopy trees than for canopy trees, reflecting ontogenetic changes in the light competition strategy from growth to persistence. With succession, both HGabs and HGbp decreased, most strongly for canopy trees, probably because of an increased exposure to drought stress. These successional changes stabilize stand size structure and reduce the rate of development.
{"title":"Height growth and biomass partitioning during secondary succession differ among forest light strata and successional guilds in a tropical rainforest","authors":"Tomonari Matsuo, Frans Bongers, Miguel Martínez-Ramos, Masha T. van der Sande, Lourens Poorter","doi":"10.1111/oik.10486","DOIUrl":"https://doi.org/10.1111/oik.10486","url":null,"abstract":"In closed-canopy systems globally, plants exhibit intense competition for light, prioritizing vertical growth to attain elevated positions within the canopy. Light competition is especially intense in tropical rainforests because of their dense shaded stands, and during forest succession because of concomitant changes in vertical light profiles. We evaluated how the height growth of individual tree differs among forest light strata (canopy, sub-canopy and understorey) and successional guilds (early, mid- and late successional species) during secondary succession in a Mexican rainforest. Fourteen secondary forest stands differing in time since agricultural abandonment (1–25 years) were monitored for seven consecutive years. For each stand and census year we estimated relative light intensity (RLI) for each height and categorized trees into forest light strata: understorey (RLI ≦ 33.3%), sub-canopy (33.3% ≦ RLI ≦ 66.6%) and canopy (RLI ≧ 66.6%), and into successional guilds based on the literature. We estimated two measures of height growth: absolute height growth (HG<sub>abs</sub>, cm year<sup>−1</sup>) calculated as the difference in tree height between two consecutive censuses, and biomass partitioning to height growth (HG<sub>bp</sub>, in kg kg<sup>−1</sup> × 100) calculated as the percentage of total aboveground biomass growth partitioned to height growth. Earlier in succession, trees for all strata had greater HG<sub>abs</sub> and HG<sub>bp</sub>, resulting in rapid vertical forest development. HG<sub>abs</sub> was fastest for canopy trees, followed by sub-canopy and understorey trees. These differences in HG<sub>abs</sub> among strata, combined with their inter-specific variation and continuous recruitment of small individuals, lead to a rapid differentiation in tree sizes and increase stand structural heterogeneity. HG<sub>bp</sub> was greater for understorey and sub-canopy trees than for canopy trees, reflecting ontogenetic changes in the light competition strategy from growth to persistence. With succession, both HG<sub>abs</sub> and HG<sub>bp</sub> decreased, most strongly for canopy trees, probably because of an increased exposure to drought stress. These successional changes stabilize stand size structure and reduce the rate of development.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"18 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140070575","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}
Miikka Benjami Laine, Dominik Martin-Creuzburg, Jaakko J. Litmanen, Sami J. Taipale
Essential biomolecules can critically influence the performance of consumers. A deficiency in dietary sterols has been shown to constrain the food quality of prokaryotic food sources for aquatic consumers. Here, we assessed the importance of dietary cholesterol for life history traits (survival, growth and egg production) of the freshwater herbivore Daphnia magna in supplementation experiments with various sterol-containing eukaryotic phytoplankton diets (dinoflagellates, diatoms, and golden algae). We combined cholesterol supplementation via liposomes with 13C-labelling of the phytoplankton diets and traced the origin of cholesterol in Daphnia using compound-specific stable isotope analysis. All phytoplankton strains used here were rich in polyunsaturated fatty acids (PUFA) but differed in their phytosterol composition. We show that growth and reproduction of D. magna can be limited by sterols even when feeding on sterol-containing eukaryotic phytoplankton diets. The impact of cholesterol supplementation on growth and reproduction of D. magna differed among phytoplankton diets (strains). The positive effect of cholesterol supplementation was most pronounced on diatom diets. Estimation of source proportions using stable isotopes revealed that D. magna preferentially assimilated the supplemented cholesterol rather than synthesizing it from dietary phytosterols. Our experiments suggest that the different responses to cholesterol supplementation on the various phytoplankton diets were unrelated to the suitability of dietary phytosterols to serve as cholesterol precursors but were caused by other biochemical or morphological food quality constraints. The combination of methods applied here could be very useful for uncovering nutritional constraints and thus for assessing the importance of essential biomolecules for the performance of herbivorous consumers.
{"title":"Sterol limitation of Daphnia on eukaryotic phytoplankton: a combined supplementation and compound-specific stable isotope labeling approach","authors":"Miikka Benjami Laine, Dominik Martin-Creuzburg, Jaakko J. Litmanen, Sami J. Taipale","doi":"10.1111/oik.10359","DOIUrl":"https://doi.org/10.1111/oik.10359","url":null,"abstract":"Essential biomolecules can critically influence the performance of consumers. A deficiency in dietary sterols has been shown to constrain the food quality of prokaryotic food sources for aquatic consumers. Here, we assessed the importance of dietary cholesterol for life history traits (survival, growth and egg production) of the freshwater herbivore <i>Daphnia magna</i> in supplementation experiments with various sterol-containing eukaryotic phytoplankton diets (dinoflagellates, diatoms, and golden algae). We combined cholesterol supplementation via liposomes with <sup>13</sup>C-labelling of the phytoplankton diets and traced the origin of cholesterol in <i>Daphnia</i> using compound-specific stable isotope analysis. All phytoplankton strains used here were rich in polyunsaturated fatty acids (PUFA) but differed in their phytosterol composition. We show that growth and reproduction of <i>D. magna</i> can be limited by sterols even when feeding on sterol-containing eukaryotic phytoplankton diets. The impact of cholesterol supplementation on growth and reproduction of <i>D. magna</i> differed among phytoplankton diets (strains). The positive effect of cholesterol supplementation was most pronounced on diatom diets. Estimation of source proportions using stable isotopes revealed that <i>D. magna</i> preferentially assimilated the supplemented cholesterol rather than synthesizing it from dietary phytosterols. Our experiments suggest that the different responses to cholesterol supplementation on the various phytoplankton diets were unrelated to the suitability of dietary phytosterols to serve as cholesterol precursors but were caused by other biochemical or morphological food quality constraints. The combination of methods applied here could be very useful for uncovering nutritional constraints and thus for assessing the importance of essential biomolecules for the performance of herbivorous consumers.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"49 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140002447","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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