Ines Klemme, Tommi Perälä, Sami O. Lehtinen, Anna Kuparinen
Parasites commonly alter the phenotype of their hosts, thereby influencing competitive and consumer–resource interactions. This could trigger a cascade effect on the dynamics of biological communities, but the role of parasites in ecosystem processes is poorly understood. In this study, we investigate how parasite-induced trait modifications shape the dynamics of a complex lake food web using an allometric trophic network model (ATN). We simulated infections of stage-structured fish host populations via increased maintenance costs and predation risk. Our results show that host trait modifications can significantly impact host demography, with stage-specific biomass declines up to 60%. However, less severely affected host stages buffered these effects and sustained the population. Importantly, host biomass decline altered the dynamics of species interactions and these effects cascaded through the entire community, with biomass changes observed at all trophic levels. Our findings emphasize the importance of incorporating both indirect parasite effects and host life history in ecological network studies for more realistic simulations of community dynamics.
{"title":"Parasite-mediated changes in host traits alter food web dynamics","authors":"Ines Klemme, Tommi Perälä, Sami O. Lehtinen, Anna Kuparinen","doi":"10.1111/oik.10374","DOIUrl":"https://doi.org/10.1111/oik.10374","url":null,"abstract":"Parasites commonly alter the phenotype of their hosts, thereby influencing competitive and consumer–resource interactions. This could trigger a cascade effect on the dynamics of biological communities, but the role of parasites in ecosystem processes is poorly understood. In this study, we investigate how parasite-induced trait modifications shape the dynamics of a complex lake food web using an allometric trophic network model (ATN). We simulated infections of stage-structured fish host populations via increased maintenance costs and predation risk. Our results show that host trait modifications can significantly impact host demography, with stage-specific biomass declines up to 60%. However, less severely affected host stages buffered these effects and sustained the population. Importantly, host biomass decline altered the dynamics of species interactions and these effects cascaded through the entire community, with biomass changes observed at all trophic levels. Our findings emphasize the importance of incorporating both indirect parasite effects and host life history in ecological network studies for more realistic simulations of community dynamics.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"10 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139559324","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}
Yuval R. Zelnik, Matthieu Barbier, David W. Shanafelt, Michel Loreau, Rachel M. Germain
Ecology is a science of scale, which guides our description of both ecological processes and patterns, but we lack a systematic understanding of how process scale and pattern scale are connected. Recent calls for synthesis between population ecology, community ecology, and ecosystem ecology motivate the integration of phenomena at multiple organizational levels. Furthermore, many studies leave out the scaling of a critical process: species interactions, which may be non-local through movement or foraging and must be distinguished from dispersal scales. Here, we use simulations to explore the consequences of three different process scales (species interactions, dispersal, and the environment) on emergent patterns of biodiversity, ecosystem functioning, and their relationship, in a spatially-explicit landscape and stable equilibrium setting. A major result of our study is that the spatial scales of dispersal and species interactions have opposite effects: a larger dispersal scale homogenizes spatial biomass patterns, while a larger interaction scale amplifies their heterogeneity. Interestingly, the specific scale at which dispersal and interaction scales begin to influence landscape patterns depends on the scale of environmental heterogeneity – in other words, the scale of one process allows important scales to emerge in other processes. This interplay between process scales, i.e. a situation where no single process dominates, can only occur when the environment is heterogeneous and the scale of dispersal small. Finally, contrary to our expectations, we observe that the spatial scale of ecological processes is more clearly reflected in landscape patterns (i.e. distribution of local outcomes) than in global patterns such as species–area relationships (SARs) or large-scale biodiversity–functioning relationships. Overall we conclude that long-range interactions often act differently and even in opposite ways to dispersal, and that the landscape patterns that emerge from the interplay of long-ranged interactions, dispersal and environmental heterogeneity are not well captured by often-used metrics like the SAR.
{"title":"Linking intrinsic scales of ecological processes to characteristic scales of biodiversity and functioning patterns","authors":"Yuval R. Zelnik, Matthieu Barbier, David W. Shanafelt, Michel Loreau, Rachel M. Germain","doi":"10.1111/oik.10514","DOIUrl":"https://doi.org/10.1111/oik.10514","url":null,"abstract":"Ecology is a science of scale, which guides our description of both ecological processes and patterns, but we lack a systematic understanding of how process scale and pattern scale are connected. Recent calls for synthesis between population ecology, community ecology, and ecosystem ecology motivate the integration of phenomena at multiple organizational levels. Furthermore, many studies leave out the scaling of a critical process: species interactions, which may be non-local through movement or foraging and must be distinguished from dispersal scales. Here, we use simulations to explore the consequences of three different process scales (species interactions, dispersal, and the environment) on emergent patterns of biodiversity, ecosystem functioning, and their relationship, in a spatially-explicit landscape and stable equilibrium setting. A major result of our study is that the spatial scales of dispersal and species interactions have opposite effects: a larger dispersal scale homogenizes spatial biomass patterns, while a larger interaction scale amplifies their heterogeneity. Interestingly, the specific scale at which dispersal and interaction scales begin to influence landscape patterns depends on the scale of environmental heterogeneity – in other words, the scale of one process allows important scales to emerge in other processes. This interplay between process scales, i.e. a situation where no single process dominates, can only occur when the environment is heterogeneous and the scale of dispersal small. Finally, contrary to our expectations, we observe that the spatial scale of ecological processes is more clearly reflected in landscape patterns (i.e. distribution of local outcomes) than in global patterns such as species–area relationships (SARs) or large-scale biodiversity–functioning relationships. Overall we conclude that long-range interactions often act differently and even in opposite ways to dispersal, and that the landscape patterns that emerge from the interplay of long-ranged interactions, dispersal and environmental heterogeneity are not well captured by often-used metrics like the SAR.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"34 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139516636","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}
Phillip J. Haubrock, Ismael Soto, Melina Kourantidou, Danish A. Ahmed, Ali Serhan Tarkan, Paride Balzani, Kristi Bego, Antonín Kouba, Sadi Aksu, Elizabeta Briski, Francisco Sylvester, Vanessa De Santis, Gaït Archambaud-Suard, Núria Bonada, Miguel Cañedo-Argüelles, Zoltán Csabai, Thibault Datry, Mathieu Floury, Jean-François Fruget, John Iwan Jones, Marie-Helene Lizee, Anthony Maire, John F. Murphy, Davis Ozolins, Jes Jessen Rasmussen, Agnija Skuja, Gábor Várbíró, Piet Verdonschot, Ralf C. M. Verdonschot, Peter Wiberg-Larsen, Ross N. Cuthbert
The zebra mussel Dreissena polymorpha is one of the most successful, notorious, and detrimental aquatic invasive non-native species worldwide, having invaded Europe and North America while causing substantial ecological and socio-economic impacts. Here, we investigated the spatiotemporal trends in this species' invasion success using 178 macroinvertebrate abundance time series, containing 1451 records of D. polymorpha collected across nine European countries between 1972–2019. Using these raw (absolute) abundance data, we examined trends and drivers of occurrences and relative abundances of D. polymorpha within invaded communities. Meta-regression models revealed non-significant trends both at the European level and for the majority of the invaded countries, except for France (significant decreasing trend) and Hungary (marginally positive trend). At the European level, the number of D. polymorpha occurrences over time followed a flat-top bell-shaped distribution, with a steep increase between 1973–1989 followed by a plateau phase prior to significantly declining post-1998. Using a series of climatic and hydromorphological site-specific characteristics of invaded and uninvaded sites from two periods (1998–2002; 2011–2015), we found that native richness, non-native abundance, distance to the next barrier, and elevation were associated with the occurrence of D. polymorpha. We also found that higher native richness and lower latitude were related to lower relative abundances. Using Cohen's D as a measure of D. polymorpha impact, we found that biodiversity within the invaded sites was initially higher than in uninvaded ones, but then declined, suggesting differences in biodiversity trends across invaded and uninvaded sites. While our results emphasise the high invasion success of D. polymorpha, increasing stressors within the context of global change – particularly ongoing climate change – are likely to enhance invasion rates and the impact of D. polymorpha in the near future, exacerbated by the lack of timely and effective management actions.
斑马贻贝（Dreissena polymorpha）是世界上最成功、最臭名昭著、危害最大的水生入侵非本地物种之一，在入侵欧洲和北美的同时对生态和社会经济造成了巨大影响。在此，我们利用 178 个大型无脊椎动物丰度时间序列研究了该物种入侵成功的时空趋势，这些时间序列包含 1972-2019 年间在 9 个欧洲国家收集的 1451 条 D. polymorpha 记录。利用这些原始（绝对）丰度数据，我们研究了被入侵群落中多甲虫的出现趋势和驱动因素以及相对丰度。元回归模型显示，除法国（显著下降趋势）和匈牙利（略呈正趋势）外，欧洲层面和大多数受入侵国家的趋势都不显著。在欧洲层面，D. polymorpha 的出现数量随着时间的推移呈平顶钟形分布，1973-1989 年间急剧上升，随后进入高原阶段，1998 年后显著下降。利用两个时期（1998-2002 年；2011-2015 年）入侵和未入侵地点的一系列气候和水文地质特征，我们发现本地丰富度、非本地丰富度、到下一个障碍物的距离和海拔与多甲藻的出现有关。我们还发现，较高的本地丰富度和较低的纬度与较低的相对丰度有关。使用科恩氏 D 作为 D. polymorpha 影响的衡量标准，我们发现受入侵地点的生物多样性最初高于未受入侵地点，但随后有所下降，这表明受入侵地点和未受入侵地点的生物多样性趋势存在差异。虽然我们的研究结果表明多甲藻的入侵成功率很高，但在全球变化（尤其是持续的气候变化）的背景下，越来越多的压力因素可能会在不久的将来提高多甲藻的入侵率和影响，而缺乏及时有效的管理措施则会加剧这种情况。
{"title":"Understanding the complex dynamics of zebra mussel invasions over several decades in European rivers: drivers, impacts and predictions","authors":"Phillip J. Haubrock, Ismael Soto, Melina Kourantidou, Danish A. Ahmed, Ali Serhan Tarkan, Paride Balzani, Kristi Bego, Antonín Kouba, Sadi Aksu, Elizabeta Briski, Francisco Sylvester, Vanessa De Santis, Gaït Archambaud-Suard, Núria Bonada, Miguel Cañedo-Argüelles, Zoltán Csabai, Thibault Datry, Mathieu Floury, Jean-François Fruget, John Iwan Jones, Marie-Helene Lizee, Anthony Maire, John F. Murphy, Davis Ozolins, Jes Jessen Rasmussen, Agnija Skuja, Gábor Várbíró, Piet Verdonschot, Ralf C. M. Verdonschot, Peter Wiberg-Larsen, Ross N. Cuthbert","doi":"10.1111/oik.10283","DOIUrl":"https://doi.org/10.1111/oik.10283","url":null,"abstract":"The zebra mussel <i>Dreissena polymorpha</i> is one of the most successful, notorious, and detrimental aquatic invasive non-native species worldwide, having invaded Europe and North America while causing substantial ecological and socio-economic impacts. Here, we investigated the spatiotemporal trends in this species' invasion success using 178 macroinvertebrate abundance time series, containing 1451 records of <i>D. polymorpha</i> collected across nine European countries between 1972–2019. Using these raw (absolute) abundance data, we examined trends and drivers of occurrences and relative abundances of <i>D. polymorpha</i> within invaded communities. Meta-regression models revealed non-significant trends both at the European level and for the majority of the invaded countries, except for France (significant decreasing trend) and Hungary (marginally positive trend). At the European level, the number of <i>D. polymorpha</i> occurrences over time followed a flat-top bell-shaped distribution, with a steep increase between 1973–1989 followed by a plateau phase prior to significantly declining post-1998. Using a series of climatic and hydromorphological site-specific characteristics of invaded and uninvaded sites from two periods (1998–2002; 2011–2015), we found that native richness, non-native abundance, distance to the next barrier, and elevation were associated with the occurrence of <i>D. polymorpha</i>. We also found that higher native richness and lower latitude were related to lower relative abundances. Using Cohen's D as a measure of <i>D. polymorpha</i> impact, we found that biodiversity within the invaded sites was initially higher than in uninvaded ones, but then declined, suggesting differences in biodiversity trends across invaded and uninvaded sites. While our results emphasise the high invasion success of <i>D. polymorpha</i>, increasing stressors within the context of global change – particularly ongoing climate change – are likely to enhance invasion rates and the impact of <i>D. polymorpha</i> in the near future, exacerbated by the lack of timely and effective management actions.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"11 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139516237","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}
Loïc Prosnier, Nicolas Loeuille, Florence D. Hulot, David Renault, Christophe Piscart, Baptiste Bicocchi, Muriel Deparis, Matthieu Lam, Vincent Médoc
Parasites are omnipresent, and their eco-evolutionary significance has aroused much interest from scientists. Parasites may affect their hosts in many ways with changes in density, appearance, behaviour and energy content, likely to modify their value to predators (profitability) within the optimal foraging framework. Consequently, parasites could impact predators' diet and the trophic links through food webs. Here, we investigate the consequences of the infection by the iridovirus Daphnia iridescent virus 1 (DIV-1) on the reproductive success, mortality, appearance, mobility, and biochemical composition of water fleas Daphnia magna, a widespread freshwater crustacean. We do predation tests and compare search time, handling time and feeding preference between infected and uninfected Daphnia when preyed upon by Notonecta sp., a common aquatic insect. Our findings show that infection does not change fecundity but reduces lifespan and thereby constrains fitness. Infected Daphnia show reduced mobility and increased color reflectance in the UV and visible domains, which potentially affects their appearance and thus vulnerability to predators. Infection increases body size and the amount of proteins but does not affect carbohydrate and lipid contents. Although infected Daphnia are longer to handle, they are preferred over uninfected individuals by aquatic insects. Taken together, our findings show that DIV-1 infection could make Daphnia more profitable to predators (24% energy increase), a positive effect that should be balanced with a lower availability due to the higher mortality of infected specimens. We also highlight that exposure to infection in asymptomatic individuals leads to ecological characteristics that differ from both healthy and symptomatic infected individuals.
{"title":"Parasites make hosts more profitable but less available to predators","authors":"Loïc Prosnier, Nicolas Loeuille, Florence D. Hulot, David Renault, Christophe Piscart, Baptiste Bicocchi, Muriel Deparis, Matthieu Lam, Vincent Médoc","doi":"10.1111/oik.10469","DOIUrl":"https://doi.org/10.1111/oik.10469","url":null,"abstract":"Parasites are omnipresent, and their eco-evolutionary significance has aroused much interest from scientists. Parasites may affect their hosts in many ways with changes in density, appearance, behaviour and energy content, likely to modify their value to predators (profitability) within the optimal foraging framework. Consequently, parasites could impact predators' diet and the trophic links through food webs. Here, we investigate the consequences of the infection by the iridovirus Daphnia iridescent virus 1 (DIV-1) on the reproductive success, mortality, appearance, mobility, and biochemical composition of water fleas <i>Daphnia magna</i>, a widespread freshwater crustacean. We do predation tests and compare search time, handling time and feeding preference between infected and uninfected <i>Daphnia</i> when preyed upon by <i>Notonecta</i> sp., a common aquatic insect. Our findings show that infection does not change fecundity but reduces lifespan and thereby constrains fitness. Infected <i>Daphnia</i> show reduced mobility and increased color reflectance in the UV and visible domains, which potentially affects their appearance and thus vulnerability to predators. Infection increases body size and the amount of proteins but does not affect carbohydrate and lipid contents. Although infected <i>Daphnia</i> are longer to handle, they are preferred over uninfected individuals by aquatic insects. Taken together, our findings show that DIV-1 infection could make <i>Daphnia</i> more profitable to predators (24% energy increase), a positive effect that should be balanced with a lower availability due to the higher mortality of infected specimens. We also highlight that exposure to infection in asymptomatic individuals leads to ecological characteristics that differ from both healthy and symptomatic infected individuals.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"61 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139516279","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}
β-diversity patterns (the compositional variations across sites) and their drivers are the major concerns of biodiversity research and conservation practices, whereas such information remains scarce for vascular epiphytes, especially in tropical forest communities. This study aimed to reveal the pattern and driving process of the compositional variations of vascular epiphytes in a tropical cloud forest on Hainan island, southern China, and their differences from those of terrestrial woody plants. To this end, we quantified their between-habitat compositional variations and distinguished the underlying components of β-diversity (nestedness and turnover). We then examined the relative roles of niche-based and neutral processes in driving the compositional variations by using a null model approach. Our results showed that the between-habitat compositional variations were significant for both plant assemblages and stronger in vascular epiphytes than in terrestrial woody plants. The turnover component of β-diversity was significantly stronger in terrestrial woody plants, accounting for 73.16–80.08% of the variations. By contrast, the nestedness component was significantly stronger in vascular epiphytes and characterized 46.82–67.5% of the variations. Besides, the compositional variations of both plant assemblages, especially terrestrial woody plants, were generally poorly fitted by the simulated niche-based scenarios but well fitted by the simulated neutral scenarios. Overall, the compositional variations of both plant assemblages were significant and mainly due to dispersal limitation, albeit to varying degrees. Hence, further studies of these plant assemblages at local scales should not be ideologically limited to the niche-based framework. Moreover, the stronger nestedness observed in vascular epiphytes suggests the greater importance of prioritizing conservation efforts in the species-rich habitats for these plants.
{"title":"Pattern and driver of the compositional variations in a tropical cloud forest: comparing vascular epiphytes with terrestrial woody plants","authors":"Chuchu Xiao, Guang Feng, Wenxing Long","doi":"10.1111/oik.10158","DOIUrl":"https://doi.org/10.1111/oik.10158","url":null,"abstract":"β-diversity patterns (the compositional variations across sites) and their drivers are the major concerns of biodiversity research and conservation practices, whereas such information remains scarce for vascular epiphytes, especially in tropical forest communities. This study aimed to reveal the pattern and driving process of the compositional variations of vascular epiphytes in a tropical cloud forest on Hainan island, southern China, and their differences from those of terrestrial woody plants. To this end, we quantified their between-habitat compositional variations and distinguished the underlying components of β-diversity (nestedness and turnover). We then examined the relative roles of niche-based and neutral processes in driving the compositional variations by using a null model approach. Our results showed that the between-habitat compositional variations were significant for both plant assemblages and stronger in vascular epiphytes than in terrestrial woody plants. The turnover component of β-diversity was significantly stronger in terrestrial woody plants, accounting for 73.16–80.08% of the variations. By contrast, the nestedness component was significantly stronger in vascular epiphytes and characterized 46.82–67.5% of the variations. Besides, the compositional variations of both plant assemblages, especially terrestrial woody plants, were generally poorly fitted by the simulated niche-based scenarios but well fitted by the simulated neutral scenarios. Overall, the compositional variations of both plant assemblages were significant and mainly due to dispersal limitation, albeit to varying degrees. Hence, further studies of these plant assemblages at local scales should not be ideologically limited to the niche-based framework. Moreover, the stronger nestedness observed in vascular epiphytes suggests the greater importance of prioritizing conservation efforts in the species-rich habitats for these plants.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"59 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139497176","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}
Jonathan M. Parrett, Marta Kulczak, Natalia Szudarek-Trepto
Climate change models predict that the frequency and intensity of heatwaves are likely to increase, therefore understanding population responses to these extreme climatic events will be key in mitigating biodiversity loss. Here, using the male dimorphic bulb mite, Rhizoglyphus robini, we investigate and compare the impact of experimental heat stress on survival and fertility between females and male morphs that differ in the expression of a sexually selected weapon. We show that lethal limits are similar among all individuals, but find clear sex differences, although no difference between morphs, in sub-lethal temperatures causing sterility: female fertility remains high close to lethal limits, whereas both male morphs suffer fertility loss at more than 2.5°C below their lethal limits. Contrastingly, when thermal stress was lower the sexes and morphs do not differ in their thermal sensitivity and declines in reproductive output are comparable. These declines appear to be additive as we observe the greatest declines when both sexes were exposed to thermal stress. In addition, during assays we included an extra treatment that allowed individuals two extra days to recover and found that fertility loss was almost fully recovered when thermal stress was low, but only partially recovered under the most extreme temperatures. The impact of heat stress on fertility therefore appears to be temporary with individuals rapidly recovering: whether recovery can negate negative population level effects remains to be investigated. Our experiments reveal the impact of heat stress on survival and fertility, finding sex-specific fertility loss under the most extreme thermal conditions.
{"title":"Fertility loss under thermal stress: males have lower fertility limits but no evidence of sex differences in sensitivity","authors":"Jonathan M. Parrett, Marta Kulczak, Natalia Szudarek-Trepto","doi":"10.1111/oik.10329","DOIUrl":"https://doi.org/10.1111/oik.10329","url":null,"abstract":"Climate change models predict that the frequency and intensity of heatwaves are likely to increase, therefore understanding population responses to these extreme climatic events will be key in mitigating biodiversity loss. Here, using the male dimorphic bulb mite, <i>Rhizoglyphus robini</i>, we investigate and compare the impact of experimental heat stress on survival and fertility between females and male morphs that differ in the expression of a sexually selected weapon. We show that lethal limits are similar among all individuals, but find clear sex differences, although no difference between morphs, in sub-lethal temperatures causing sterility: female fertility remains high close to lethal limits, whereas both male morphs suffer fertility loss at more than 2.5°C below their lethal limits. Contrastingly, when thermal stress was lower the sexes and morphs do not differ in their thermal sensitivity and declines in reproductive output are comparable. These declines appear to be additive as we observe the greatest declines when both sexes were exposed to thermal stress. In addition, during assays we included an extra treatment that allowed individuals two extra days to recover and found that fertility loss was almost fully recovered when thermal stress was low, but only partially recovered under the most extreme temperatures. The impact of heat stress on fertility therefore appears to be temporary with individuals rapidly recovering: whether recovery can negate negative population level effects remains to be investigated. Our experiments reveal the impact of heat stress on survival and fertility, finding sex-specific fertility loss under the most extreme thermal conditions.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"31 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139497175","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}
Werner Ulrich, Jan Christian Habel, Patrick Gros, Thomas Schmitt
In Europe, abundance, biomass and species richness of many insect taxa declined during the last decades. This decline might be accompanied by long-term temporal changes in community composition and dominance orders. Here, we use the data base of the natural history museum of Salzburg based on museum records and field books on Austrian butterflies covering the years 1945–2018 and asked 1) whether and how community composition of important butterfly guilds changed and 2) whether these changes are in accordance with reciprocal shifts in species abundances leading to increased functional stability. In comparisons of annual changes in dominance orders, we found an increasing tendency of compositional stability of dominant species. The trend was most pronounced in generalist and dispersive species, while dominant grassland, xerothermophilic and sedentary species tended to decrease in relative abundance. We also demonstrate a temporal trend towards increasing regional stability in relative abundance rank orders. We did not find compelling evidence for reciprocal shifts in abundances of dominant and subdominant species of the same guild and of asynchronous population fluctuations as required by models that link abundance compensation and functional stability. Our study highlights the ongoing trend towards faunal homogenisation at regional spatial scales in the European Alps.
{"title":"Recent increasing homogenisation in Austrian butterfly communities over the past decades","authors":"Werner Ulrich, Jan Christian Habel, Patrick Gros, Thomas Schmitt","doi":"10.1111/oik.10179","DOIUrl":"https://doi.org/10.1111/oik.10179","url":null,"abstract":"In Europe, abundance, biomass and species richness of many insect taxa declined during the last decades. This decline might be accompanied by long-term temporal changes in community composition and dominance orders. Here, we use the data base of the natural history museum of Salzburg based on museum records and field books on Austrian butterflies covering the years 1945–2018 and asked 1) whether and how community composition of important butterfly guilds changed and 2) whether these changes are in accordance with reciprocal shifts in species abundances leading to increased functional stability. In comparisons of annual changes in dominance orders, we found an increasing tendency of compositional stability of dominant species. The trend was most pronounced in generalist and dispersive species, while dominant grassland, xerothermophilic and sedentary species tended to decrease in relative abundance. We also demonstrate a temporal trend towards increasing regional stability in relative abundance rank orders. We did not find compelling evidence for reciprocal shifts in abundances of dominant and subdominant species of the same guild and of asynchronous population fluctuations as required by models that link abundance compensation and functional stability. Our study highlights the ongoing trend towards faunal homogenisation at regional spatial scales in the European Alps.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"21 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139497426","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}
Matthew W. Rees, Brendan A. Wintle, Jack H. Pascoe, Mark Le Pla, Emma K. Birnbaum, Bronwyn A. Hradsky
Understanding the constraints that dominant predators impose on subordinate species is important for predicting ecosystem dynamics and anticipating outcomes of predator management. Subordinate predators may avoid dominant predators in time or space, making it difficult to quantify antipredator behaviours unless joint spatiotemporal analyses are used. Here, we test whether an invasive dominant predator (red fox Vulpes vulpes) alters the spatiotemporal activity of an invasive subordinate predator (feral cat Felis catus). We collated records of both species from 3667 camera-traps deployed experimentally across two regions of south-eastern Australia with simplified predator guilds. Foxes were poison-baited in some landscapes within each region. We used generalised additive models to quantify changes in predator spatiotemporal activity across geographic space, vegetation types, human footprints and (artificially manipulated) gradients of dominant predator activity. Foxes and cats had similar diel activity patterns when averaged across all sites, but there was important differentiation at a finer scale: cats did not reduce their spatial activity but shifted diel patterns when localised fox activity was high. Cats were crepuscular on average. However, across dry vegetation types of both regions (where foxes were nocturnal), cats shifted to diurnal behaviour with increasing fox activity. In contrast, fox activity was relatively consistent throughout the daily cycle in the wet forest; here cats avoided dawn when fox activity was high. Changes in cat diel activity patterns may facilitate spatial coexistence between these two invasive predators, potentially shifting feral cat impacts onto different native prey. While it is well-appreciated that predator activity varies spatially and fluctuates throughout the daily cycle,our study demonstrates that diel activity patterns also vary across space, likely mediated by both landscape-context and fear. Dominant predator avoidance in time also appears to be spatially dynamic – a key nuance overlooked when simply comparing the average activity overlap between two species.
{"title":"Dynamic shifts in predator diel activity patterns across landscapes and threat levels","authors":"Matthew W. Rees, Brendan A. Wintle, Jack H. Pascoe, Mark Le Pla, Emma K. Birnbaum, Bronwyn A. Hradsky","doi":"10.1111/oik.09849","DOIUrl":"https://doi.org/10.1111/oik.09849","url":null,"abstract":"Understanding the constraints that dominant predators impose on subordinate species is important for predicting ecosystem dynamics and anticipating outcomes of predator management. Subordinate predators may avoid dominant predators in time or space, making it difficult to quantify antipredator behaviours unless joint spatiotemporal analyses are used. Here, we test whether an invasive dominant predator (red fox <i>Vulpes vulpes</i>) alters the spatiotemporal activity of an invasive subordinate predator (feral cat <i>Felis catus</i>). We collated records of both species from 3667 camera-traps deployed experimentally across two regions of south-eastern Australia with simplified predator guilds. Foxes were poison-baited in some landscapes within each region. We used generalised additive models to quantify changes in predator spatiotemporal activity across geographic space, vegetation types, human footprints and (artificially manipulated) gradients of dominant predator activity. Foxes and cats had similar diel activity patterns when averaged across all sites, but there was important differentiation at a finer scale: cats did not reduce their spatial activity but shifted diel patterns when localised fox activity was high. Cats were crepuscular on average. However, across dry vegetation types of both regions (where foxes were nocturnal), cats shifted to diurnal behaviour with increasing fox activity. In contrast, fox activity was relatively consistent throughout the daily cycle in the wet forest; here cats avoided dawn when fox activity was high. Changes in cat diel activity patterns may facilitate spatial coexistence between these two invasive predators, potentially shifting feral cat impacts onto different native prey. While it is well-appreciated that predator activity varies spatially and fluctuates throughout the daily cycle,our study demonstrates that diel activity patterns also vary across space, likely mediated by both landscape-context and fear. Dominant predator avoidance in time also appears to be spatially dynamic – a key nuance overlooked when simply comparing the average activity overlap between two species.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"97 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139497198","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}
Cedric Villasor, Kateri Robertson, Thomas Becker, James F. Cahill, Balázs Deák, Isabell Hensen, Rafael Otfinowski, Christoph Rosche, Dariia Borovyk, Tatyana Vakhlamova, Orsolya Valkó, Viktoria Wagner
Empirical invasion ecology is laden with high context dependency. If general mechanisms underlying invasion success exist, they should be detectable in species that share biological and ecological characteristics. We carried out a growth experiment with Agropyron cristatum, Bromus inermis and Poa pratensis (subsp. angustifolia), to better understand the mechanisms underlying the invasion success of cool-season grasses in northern prairie grasslands of North America. By using a home–away approach, we tested whether 1) non-native plants have a higher performance than native plants, and whether invasiveness is 2) mediated by interactions with soils, such as a release from pathogens or enhanced mutualism, or 3) an adaptation to local soils. We compared seed size and weight of populations in Canada (non-native range) and Eurasia (native range) and carried out an experiment, in which seeds from the non-native and native ranges were planted into sterilized soil (control) and soil from a population in Canada or Eurasia, or local soils, respectively. We found inconsistent effects across species and response variables. Seed size and weight were not significantly different between native and non-native populations. The experiment showed a seed origin effect in A. cristatum (root and total biomass) and B. inermis (root biomass), with non-native populations outperforming native ones. Soil-mediated effects were supported in A. cristatum (root biomass) and local adaptation in B. inermis (root and total biomass). Germination across all species and biomass in P. pratensis did not respond to treatments. Despite the high similarity of our study group, our results indicate that invasiveness might be driven by idiosyncratic causes at the species level. Mechanisms not considered in our study, such as high propagule pressure and preadaptation could also potentially explain the invasion success across species.
经验入侵生态学具有高度的环境依赖性。如果存在影响入侵成功的一般机制，那么这些机制应该可以在具有相同生物和生态特征的物种中检测到。我们用Agropyron cristatum、Bromus inermis和Poa pratensis（subsp. angustifolia）进行了一次生长实验，以更好地了解北美北部草原冷季型禾本科植物入侵成功的内在机制。我们采用了一种 "回避 "的方法，测试了 1）非本地植物是否比本地植物具有更高的表现，以及入侵性是否 2）通过与土壤的相互作用（如病原体的释放或增强的互作关系）而介导，或 3）对当地土壤的适应。我们比较了加拿大（非外来分布区）和欧亚大陆（本地分布区）种群的种子大小和重量，并进行了一项实验，将非外来分布区和本地分布区的种子分别种植到灭菌土壤（对照）、加拿大或欧亚大陆种群的土壤或当地土壤中。我们发现不同物种和反应变量之间的影响并不一致。种子大小和重量在本地种群和非本地种群之间没有明显差异。实验表明，A. cristatum（根和总生物量）和 B. inermis（根生物量）存在种子来源效应，非本地种群的表现优于本地种群。土壤介导效应在 A. cristatum（根生物量）和 B. inermis（根和总生物量）中得到支持。所有物种的发芽率和 P. pratensis 的生物量都没有受到处理的影响。尽管我们的研究小组具有很高的相似性，但我们的结果表明，入侵性可能是由物种水平上的特殊原因驱动的。我们的研究没有考虑到的机制，如高传播压力和预适应，也有可能解释不同物种的入侵成功率。
{"title":"Invasion success of three cool-season grasses in the northern prairie: a test of three hypotheses","authors":"Cedric Villasor, Kateri Robertson, Thomas Becker, James F. Cahill, Balázs Deák, Isabell Hensen, Rafael Otfinowski, Christoph Rosche, Dariia Borovyk, Tatyana Vakhlamova, Orsolya Valkó, Viktoria Wagner","doi":"10.1111/oik.10266","DOIUrl":"https://doi.org/10.1111/oik.10266","url":null,"abstract":"Empirical invasion ecology is laden with high context dependency. If general mechanisms underlying invasion success exist, they should be detectable in species that share biological and ecological characteristics. We carried out a growth experiment with <i>Agropyron cristatum</i>, <i>Bromus inermis</i> and <i>Poa pratensis</i> (subsp. <i>angustifolia</i>), to better understand the mechanisms underlying the invasion success of cool-season grasses in northern prairie grasslands of North America. By using a home–away approach, we tested whether 1) non-native plants have a higher performance than native plants, and whether invasiveness is 2) mediated by interactions with soils, such as a release from pathogens or enhanced mutualism, or 3) an adaptation to local soils. We compared seed size and weight of populations in Canada (non-native range) and Eurasia (native range) and carried out an experiment, in which seeds from the non-native and native ranges were planted into sterilized soil (control) and soil from a population in Canada or Eurasia, or local soils, respectively. We found inconsistent effects across species and response variables. Seed size and weight were not significantly different between native and non-native populations. The experiment showed a seed origin effect in <i>A</i>. <i>cristatum</i> (root and total biomass) and <i>B</i>. <i>inermis</i> (root biomass), with non-native populations outperforming native ones. Soil-mediated effects were supported in <i>A</i>. <i>cristatum</i> (root biomass) and local adaptation in <i>B</i>. <i>inermis</i> (root and total biomass). Germination across all species and biomass in <i>P</i>. <i>pratensis</i> did not respond to treatments. Despite the high similarity of our study group, our results indicate that invasiveness might be driven by idiosyncratic causes at the species level. Mechanisms not considered in our study, such as high propagule pressure and preadaptation could also potentially explain the invasion success across species.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"10 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139497339","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}
Laynara Figueiredo Lugli, Lucia Fuchslueger, Helena Vallicrosa, Leandro Van Langenhove, Christian Ranits, Pere Roc Fernandez Garberi, Lore Verryckt, Oriol Grau, Laëtitia Bréchet, Guille Peguero, Joan Llusia, Romà Ogaya, Laura Marquez, Miguel Portillo-Estrada, Irene Ramirez-Rojas, Elodie Courtois, Clement Stahl, Jordi Sardans, Josep Penuelas, Erik Verbruggen, Janssens Ivan
Fine roots mediate plant nutrient acquisition and growth. Depending on soil nutrient availability, plants can regulate fine root biomass and morphological traits to optimise nutrient acquisition. Little is known, however, about the importance of these parameters influencing forest functioning. In this study, we measured root responses to nutrient additions to gain a mechanistic understanding of plant adaptations to nutrient limitation in two tropical forests in French Guiana, differing twofold in their soil nutrient statuses. We analysed the responses of root biomass, mean root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD) and carbon (C), nitrogen (N) and phosphorus (P) concentrations in roots down to 15 cm soil depth after three years of N and P additions. At the lower-fertility site Paracou, no changes in root biomass or morphological traits were detected with either N or P addition, although P concentrations in roots increased with P addition. In the higher fertility site, Nouragues, root biomass and P concentrations in roots increased with P addition, with no changes in morphological traits. In contrast, N addition shifted root traits from acquisitive to more conservative by increasing RTD. A significant interaction between N and P in Nouragues pointed to stronger responses to P addition in the absence of N. Our results suggest that the magnitude and direction of root biomass and trait expression were regulated by soil fertility, corroborated by the response to N or P additions. At low fertility sites, we found lower plasticity in root trait expression compared to more fertile conditions, where N and P additions caused stronger and antagonistic responses. Identifying the exact role of mechanisms affecting root nutrient uptake in Amazon forests growing in different soils will be crucial to foresee if and how rapid global changes can affect their carbon allocation.
{"title":"Contrasting responses of fine root biomass and traits to large-scale nitrogen and phosphorus addition in tropical forests in the Guiana shield","authors":"Laynara Figueiredo Lugli, Lucia Fuchslueger, Helena Vallicrosa, Leandro Van Langenhove, Christian Ranits, Pere Roc Fernandez Garberi, Lore Verryckt, Oriol Grau, Laëtitia Bréchet, Guille Peguero, Joan Llusia, Romà Ogaya, Laura Marquez, Miguel Portillo-Estrada, Irene Ramirez-Rojas, Elodie Courtois, Clement Stahl, Jordi Sardans, Josep Penuelas, Erik Verbruggen, Janssens Ivan","doi":"10.1111/oik.10412","DOIUrl":"https://doi.org/10.1111/oik.10412","url":null,"abstract":"Fine roots mediate plant nutrient acquisition and growth. Depending on soil nutrient availability, plants can regulate fine root biomass and morphological traits to optimise nutrient acquisition. Little is known, however, about the importance of these parameters influencing forest functioning. In this study, we measured root responses to nutrient additions to gain a mechanistic understanding of plant adaptations to nutrient limitation in two tropical forests in French Guiana, differing twofold in their soil nutrient statuses. We analysed the responses of root biomass, mean root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD) and carbon (C), nitrogen (N) and phosphorus (P) concentrations in roots down to 15 cm soil depth after three years of N and P additions. At the lower-fertility site Paracou, no changes in root biomass or morphological traits were detected with either N or P addition, although P concentrations in roots increased with P addition. In the higher fertility site, Nouragues, root biomass and P concentrations in roots increased with P addition, with no changes in morphological traits. In contrast, N addition shifted root traits from acquisitive to more conservative by increasing RTD. A significant interaction between N and P in Nouragues pointed to stronger responses to P addition in the absence of N. Our results suggest that the magnitude and direction of root biomass and trait expression were regulated by soil fertility, corroborated by the response to N or P additions. At low fertility sites, we found lower plasticity in root trait expression compared to more fertile conditions, where N and P additions caused stronger and antagonistic responses. Identifying the exact role of mechanisms affecting root nutrient uptake in Amazon forests growing in different soils will be crucial to foresee if and how rapid global changes can affect their carbon allocation.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"269 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139475866","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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