Despite their ecological significance, non‐vascular photoautotrophs (NVPs) are frequently excluded from ecological experimental studies, leading to a limited comprehension of how their communities are affected by the ecosystem dynamics and an underestimation of their role in ecosystem functioning. We studied the impact of vascular plant taxonomic and functional diversity on three groups of ground NVPs (lichens, bryophytes, and cyanobacteria) within one of the longest‐running plant biodiversity experiments (Biodiversity and Ecosystem Function at Cedar Creek Ecosystem Science Reserve). Utilizing the permanent plot framework of this experiment, we analyzed the effects of almost 30 years of treatment across various levels of vascular plant taxonomic and functional diversity on NVPs. For each diversity level we documented NVP cover and richness. Using generalized linear models we evaluated the effect of vascular plant taxonomic and functional diversity, as well as environmental factors affected by vascular diversity (such as vascular plant cover, light penetration, soil nutrient content, and microtopography) on NVP richness and cover. Using these models, we conducted structural equation modeling analyses (SEM) that allowed us to differentiate the direct and indirect impacts of vascular plant taxonomic and functional diversity on NVPs. Our results showed that both lichen and bryophyte richness and cover decreased with higher vascular plant taxonomic and functional diversity, while cyanobacteria cover increased as a function of the same parameters. We also showed that microtopography serves as better predictor for lichens and bryophytes, while nutrient‐related factors perform better as predictors for cyanobacteria. Additionally, our findings indicate that NVP cover ranged from 0.001% to 100% (mean 15%) in the surveyed plots, representing a major, still ignored, component of the experimental plots. This study shows that vascular plant diversity directly and indirectly affects NVP communities, but the consequences of these effects at community and ecosystem levels are still to be explored.
{"title":"Vascular plant taxonomic and functional richness differentially affect non‐vascular photoautotroph communities","authors":"Mariana Cárdenas‐Henao, Daniel E. Stanton","doi":"10.1111/oik.10494","DOIUrl":"https://doi.org/10.1111/oik.10494","url":null,"abstract":"Despite their ecological significance, non‐vascular photoautotrophs (NVPs) are frequently excluded from ecological experimental studies, leading to a limited comprehension of how their communities are affected by the ecosystem dynamics and an underestimation of their role in ecosystem functioning. We studied the impact of vascular plant taxonomic and functional diversity on three groups of ground NVPs (lichens, bryophytes, and cyanobacteria) within one of the longest‐running plant biodiversity experiments (Biodiversity and Ecosystem Function at Cedar Creek Ecosystem Science Reserve). Utilizing the permanent plot framework of this experiment, we analyzed the effects of almost 30 years of treatment across various levels of vascular plant taxonomic and functional diversity on NVPs. For each diversity level we documented NVP cover and richness. Using generalized linear models we evaluated the effect of vascular plant taxonomic and functional diversity, as well as environmental factors affected by vascular diversity (such as vascular plant cover, light penetration, soil nutrient content, and microtopography) on NVP richness and cover. Using these models, we conducted structural equation modeling analyses (SEM) that allowed us to differentiate the direct and indirect impacts of vascular plant taxonomic and functional diversity on NVPs. Our results showed that both lichen and bryophyte richness and cover decreased with higher vascular plant taxonomic and functional diversity, while cyanobacteria cover increased as a function of the same parameters. We also showed that microtopography serves as better predictor for lichens and bryophytes, while nutrient‐related factors perform better as predictors for cyanobacteria. Additionally, our findings indicate that NVP cover ranged from 0.001% to 100% (mean 15%) in the surveyed plots, representing a major, still ignored, component of the experimental plots. This study shows that vascular plant diversity directly and indirectly affects NVP communities, but the consequences of these effects at community and ecosystem levels are still to be explored.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"42 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141739831","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}
Anthropogenic activities are causing a steep decline of wildlife populations. Increased inbreeding in shrinking populations can substantially curb individual fitness and population viability. One potentially important but largely ignored component of inbreeding depression may be cognitive decline. Cognition affects an animal's capacity to respond to environmental disturbance, which, in the face of global change, may make the difference between persistence and extinction. While the effects of inbreeding on cognitive performance have been relatively well documented in humans, they remain largely unexplored in natural populations. Here we review the current (limited) knowledge on whether and how inbreeding impinges on animals' cognitive abilities. Insights into the relationship between inbreeding and cognition could prove valuable not only for comprehending the development and evolution of cognition but also for conservation.
{"title":"Inbreeding and cognition in wild populations: a relationship that remains unnoticed","authors":"Ioanna Gavriilidi, Lisa Van Linden","doi":"10.1111/oik.10674","DOIUrl":"https://doi.org/10.1111/oik.10674","url":null,"abstract":"Anthropogenic activities are causing a steep decline of wildlife populations. Increased inbreeding in shrinking populations can substantially curb individual fitness and population viability. One potentially important but largely ignored component of inbreeding depression may be cognitive decline. Cognition affects an animal's capacity to respond to environmental disturbance, which, in the face of global change, may make the difference between persistence and extinction. While the effects of inbreeding on cognitive performance have been relatively well documented in humans, they remain largely unexplored in natural populations. Here we review the current (limited) knowledge on whether and how inbreeding impinges on animals' cognitive abilities. Insights into the relationship between inbreeding and cognition could prove valuable not only for comprehending the development and evolution of cognition but also for conservation.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"82 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141739832","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}
Deterministic factors including homogeneous and heterogeneous selection and stochastic factors jointly shape ecological communities. However, a quantitative synthesis of the factors underlying the balance among different assembly processes is lacking. Here, we synthesized data from 149 datasets covering major biotic groups and ecosystem types globally. We used a null model approach based on Raup–Crick dissimilarities and Bayesian meta‐regression to analyze the data. We found that communities were more under homogeneous selection than heterogeneous selection across biotic taxa and ecosystems. Environment selected species homogeneously more often at small scales while heterogeneously more often at large scales. Stochasticity also showed scale‐dependence as stochastic community assembly increased with study scale. Homogeneous and heterogeneous selection were strongest at high latitudes while stochastic factors were strongest in tropics. Marine systems had the highest degree of homogeneous selection and the lowest stochasticity. We provide the first analysis of community assembly across taxa and ecosystems which should be important for a better understanding of how communities respond to environmental change.
{"title":"Homogeneous selection and stochasticity overrule heterogeneous selection across biotic taxa and ecosystems","authors":"Janne Soininen, Caio Graco‐Roza","doi":"10.1111/oik.10517","DOIUrl":"https://doi.org/10.1111/oik.10517","url":null,"abstract":"Deterministic factors including homogeneous and heterogeneous selection and stochastic factors jointly shape ecological communities. However, a quantitative synthesis of the factors underlying the balance among different assembly processes is lacking. Here, we synthesized data from 149 datasets covering major biotic groups and ecosystem types globally. We used a null model approach based on Raup–Crick dissimilarities and Bayesian meta‐regression to analyze the data. We found that communities were more under homogeneous selection than heterogeneous selection across biotic taxa and ecosystems. Environment selected species homogeneously more often at small scales while heterogeneously more often at large scales. Stochasticity also showed scale‐dependence as stochastic community assembly increased with study scale. Homogeneous and heterogeneous selection were strongest at high latitudes while stochastic factors were strongest in tropics. Marine systems had the highest degree of homogeneous selection and the lowest stochasticity. We provide the first analysis of community assembly across taxa and ecosystems which should be important for a better understanding of how communities respond to environmental change.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"23 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141585070","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}
The Charnov‐Bull hypothesis is the leading explanation for the evolution of environmental sex determination (ESD), which includes temperature‐dependent sex determination (TSD), the most common form of ESD. Charnov‐Bull predicts a sex‐by‐incubation temperature interaction for fitness, matching offspring sex with thermal conditions that increase parental fitness. However, there is no general explanation for how the sex‐by‐temperature interaction arises. Two competing explanations for the interaction lie in the survival to maturity hypothesis (SM) and the Trivers–Willard extension (TW). Under SM, the sex that matures later is produced under optimal incubation regimes as the late‐maturing sex accrues more mortality by maturation, while TW suggests that males are always produced under optimal incubation regimes as male mating success is more sensitive to condition (general health, vigor) than female fecundity. In a system where females mature later than males, as in the painted turtle Chrysemys picta, SM and TW generate opposite predictions for the effect of incubation temperature on juvenile survival. We incubated C. picta eggs under either female‐promoting temperatures (28 ± 3 °C) or male‐promoting temperatures (25 ± 3 °C), then released the hatchlings into their natal pond. We used a Bayesian capture–mark–recapture approach to follow their survival over two growing seasons. We found a 2% depression of biweekly survival in individuals incubated under the cooler temperature, providing subtle support for SM. Incubation treatments did not influence growth. Large‐scale field experiments such as this one will be necessary for understanding TSD evolution, and we underline general principles to execute such experiments successfully.
{"title":"The thermal sensitivity of growth and survival in a wild reptile with temperature‐dependent sex determination","authors":"Jessica A. Leivesley, Njal Rollinson","doi":"10.1111/oik.10706","DOIUrl":"https://doi.org/10.1111/oik.10706","url":null,"abstract":"The Charnov‐Bull hypothesis is the leading explanation for the evolution of environmental sex determination (ESD), which includes temperature‐dependent sex determination (TSD), the most common form of ESD. Charnov‐Bull predicts a sex‐by‐incubation temperature interaction for fitness, matching offspring sex with thermal conditions that increase parental fitness. However, there is no general explanation for how the sex‐by‐temperature interaction arises. Two competing explanations for the interaction lie in the survival to maturity hypothesis (SM) and the Trivers–Willard extension (TW). Under SM, the sex that matures later is produced under optimal incubation regimes as the late‐maturing sex accrues more mortality by maturation, while TW suggests that males are always produced under optimal incubation regimes as male mating success is more sensitive to condition (general health, vigor) than female fecundity. In a system where females mature later than males, as in the painted turtle <jats:italic>Chrysemys picta</jats:italic>, SM and TW generate opposite predictions for the effect of incubation temperature on juvenile survival. We incubated <jats:italic>C. picta</jats:italic> eggs under either female‐promoting temperatures (28 ± 3 °C) or male‐promoting temperatures (25 ± 3 °C), then released the hatchlings into their natal pond. We used a Bayesian capture–mark–recapture approach to follow their survival over two growing seasons. We found a 2% depression of biweekly survival in individuals incubated under the cooler temperature, providing subtle support for SM. Incubation treatments did not influence growth. Large‐scale field experiments such as this one will be necessary for understanding TSD evolution, and we underline general principles to execute such experiments successfully.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"81 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512068","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}
Simon Bazin, Virginie Diouloufet, Ange Molina, Tiphaine Peroux, Jose M. Montoya, Simon Blanchet, Eric Edeline, Stéphan Jacquet, Serena Rasconi, Stéphanie Fayolle, Marina Campana, Thalia Zambeaux, Camille Leclerc, Rémy Lassus, Julie Morla, Martin Daufresne, Arnaud Sentis
Theory predicts that morphological and bioenergetic constraints due to temperature‐induced body size reduction can modulate the direct effects of warming on biotic interactions, with consequent effects on trophic cascades and biomass distribution. However, these theoretical predictions have rarely been tested empirically. Our aim was to distinguish the indirect effects of warming‐induced body size reductions from the direct effects of warming on community structure. We conducted a mesocosm experiment manipulating factorially 1) body size reduction in the medaka fish Oryzias latipes using two populations raised for several generations under contrasted climate conditions and 2) warming (+4°C), to test their independent and interactive effects on the structure of prey and primary resource communities, the predator–prey biomass ratio and the biomass size spectra. We further dissected the effects of seasonal temperature variation from the effects of constant artificial warming. We found that the indirect effects of warming (i.e. fish body size reduction) on composition and structure of communities as well as their biomass size spectra were of marginal amplitude compared to the direct effects of seasonal temperature variation and constant warming. There were no changes in community composition in response to fish body size reduction or constant warming. However, the density of macroinvertebrates and zooplankton were maximal at intermediate seasonal water temperatures and lower in constantly‐heated mesocosms. Contrastingly, phytoplankton was not strongly affected by seasonal temperature or warming, but rather responded to grazing effects of zooplankton. Finally, we found a reduction in predator–prey biomass ratio under warming and at the warmest seasonal temperature, inducing a steeper slope of the biomass size spectra under increasing seasonal (but not constant) temperature. We conclude that the direct effects of climate change on freshwater communities are stronger than its indirect effects mediated by body mass reduction.
{"title":"Direct effect of artificial warming on communities is stronger than its indirect effect through body mass reduction","authors":"Simon Bazin, Virginie Diouloufet, Ange Molina, Tiphaine Peroux, Jose M. Montoya, Simon Blanchet, Eric Edeline, Stéphan Jacquet, Serena Rasconi, Stéphanie Fayolle, Marina Campana, Thalia Zambeaux, Camille Leclerc, Rémy Lassus, Julie Morla, Martin Daufresne, Arnaud Sentis","doi":"10.1111/oik.10561","DOIUrl":"https://doi.org/10.1111/oik.10561","url":null,"abstract":"Theory predicts that morphological and bioenergetic constraints due to temperature‐induced body size reduction can modulate the direct effects of warming on biotic interactions, with consequent effects on trophic cascades and biomass distribution. However, these theoretical predictions have rarely been tested empirically. Our aim was to distinguish the indirect effects of warming‐induced body size reductions from the direct effects of warming on community structure. We conducted a mesocosm experiment manipulating factorially 1) body size reduction in the medaka fish <jats:italic>Oryzias latipes</jats:italic> using two populations raised for several generations under contrasted climate conditions and 2) warming (+4°C), to test their independent and interactive effects on the structure of prey and primary resource communities, the predator–prey biomass ratio and the biomass size spectra. We further dissected the effects of seasonal temperature variation from the effects of constant artificial warming. We found that the indirect effects of warming (i.e. fish body size reduction) on composition and structure of communities as well as their biomass size spectra were of marginal amplitude compared to the direct effects of seasonal temperature variation and constant warming. There were no changes in community composition in response to fish body size reduction or constant warming. However, the density of macroinvertebrates and zooplankton were maximal at intermediate seasonal water temperatures and lower in constantly‐heated mesocosms. Contrastingly, phytoplankton was not strongly affected by seasonal temperature or warming, but rather responded to grazing effects of zooplankton. Finally, we found a reduction in predator–prey biomass ratio under warming and at the warmest seasonal temperature, inducing a steeper slope of the biomass size spectra under increasing seasonal (but not constant) temperature. We conclude that the direct effects of climate change on freshwater communities are stronger than its indirect effects mediated by body mass reduction.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"18 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141530374","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}
Javier Valverde, Mónica Medrano, Carlos M. Herrera, Conchita Alonso
In flowering plants, pollinators contribute to gene flow while they also respond to variation in plant traits together determined by genetic, epigenetic and environmental sources of variation. Consequently, a correlation between abundance and diversity of pollinators and the genetic and epigenetic characteristics of plant populations such as diversity or distinctiveness is expected. However, no study has explored these long‐term dimensions of plant–pollinator interactions. Mediterranean narrow endemics often exhibit unexpectedly high levels of population genetic and epigenetic diversity. We hypothesize that pollinators may contribute to explain this pattern. Specifically, given the higher sensitivity of small, isolated population to gene flow, we expect a stronger association of pollinators with population genetic and epigenetic variability in narrow endemics than in widely distributed congeners. We studied five pairs of congeneric plant species, consisting of one narrow endemic with a restricted distribution and one widespread congener, found in the Sierra de Cazorla mountains (SE Spain). We characterized the pollinators in up to three populations per species to estimate their diversity and visitation rates. Additionally, we calculated the genetic and epigenetic diversity and distinctiveness of each population using AFLP markers and methylation‐sensitive AFLP markers (MSAP), respectively. We assessed the relationship between pollinator diversity and visitation rates. The diversity of pollinators did not vary according to the plant´s distribution range, but visitation rate was higher in widespread species. As predicted, only narrow endemics showed a significant association between pollinators and their population genetic and epigenetic characteristics. Specifically, higher pollinator diversity and visitation rates entailed higher population genetic diversity and lower epigenetic distinctiveness. This work shows the importance of investigating the relationship between pollinator diversity and population genetics and epigenetics to better understand the evolution of plant rarity.
{"title":"Assessing the links between pollinators and the genetic and epigenetic features of plant species with contrasting distribution ranges","authors":"Javier Valverde, Mónica Medrano, Carlos M. Herrera, Conchita Alonso","doi":"10.1111/oik.10312","DOIUrl":"https://doi.org/10.1111/oik.10312","url":null,"abstract":"In flowering plants, pollinators contribute to gene flow while they also respond to variation in plant traits together determined by genetic, epigenetic and environmental sources of variation. Consequently, a correlation between abundance and diversity of pollinators and the genetic and epigenetic characteristics of plant populations such as diversity or distinctiveness is expected. However, no study has explored these long‐term dimensions of plant–pollinator interactions. Mediterranean narrow endemics often exhibit unexpectedly high levels of population genetic and epigenetic diversity. We hypothesize that pollinators may contribute to explain this pattern. Specifically, given the higher sensitivity of small, isolated population to gene flow, we expect a stronger association of pollinators with population genetic and epigenetic variability in narrow endemics than in widely distributed congeners. We studied five pairs of congeneric plant species, consisting of one narrow endemic with a restricted distribution and one widespread congener, found in the Sierra de Cazorla mountains (SE Spain). We characterized the pollinators in up to three populations per species to estimate their diversity and visitation rates. Additionally, we calculated the genetic and epigenetic diversity and distinctiveness of each population using AFLP markers and methylation‐sensitive AFLP markers (MSAP), respectively. We assessed the relationship between pollinator diversity and visitation rates. The diversity of pollinators did not vary according to the plant´s distribution range, but visitation rate was higher in widespread species. As predicted, only narrow endemics showed a significant association between pollinators and their population genetic and epigenetic characteristics. Specifically, higher pollinator diversity and visitation rates entailed higher population genetic diversity and lower epigenetic distinctiveness. This work shows the importance of investigating the relationship between pollinator diversity and population genetics and epigenetics to better understand the evolution of plant rarity.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"63 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512069","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}
Mariano I. Giombini, Diana Pésole, Anuncio Daniel Benítez, Sebastián A. Costa, L. Fernando Foletto, C. Esteban Pizzio, Ana L. Dip Yordanoff, M. Genoveva Gatti, Mario S. Di Bitetti
The downsizing of disperser assemblages by selective defaunation is a worldwide phenomenon thought to have important consequences in animal‐dispersed plants. Numerous large‐seeded Neotropical plants currently depend on the last megafaunal survivors, the large tapirs Tapirus spp., and medium‐sized frugivores. The extent to which medium frugivores are functionally equivalent to tapirs remains unresolved. We combined feeding trials, seed dispersal kernel modeling based on seed retention times and animal movement simulation (Levy walks), and germination experiments in a large‐seeded palm to assess the dispersal quality provided by the largest (tapirs) and two medium (foxes and howler monkeys) frugivore species in terms of dispersal distances and gut passage effects on germination. Tapirs retained the seeds in the gut for much longer (mean = 221 hours) than howlers (43 h) and foxes (22 h). Median dispersal distance by tapirs (1252 m) was 14 and 40 times larger than that by foxes (88 m) and howlers (31 m), respectively. The seed dispersal kernel of tapirs showed a 5th percentile value (291 m) larger than the 95th percentiles of foxes (285 m) and howlers (108 m). Manually depulped and gut‐passed seeds germinated in similar proportions, showing, respectively, 3.5 and 2.5–2.9 times higher values than intact fruits. Germination probability and seed viability decreased with retention time in howlers' and tapirs' gut, with howlers showing a steeper negative relationship. Such detrimental effect implies a trade‐off between germination success and dispersal distance. We conclude that tapirs may not play a unique role in germination enhancement but move seeds much further than medium frugivores, thus playing a critical role as long‐distance dispersers of many plants. This study provides important insights on palm–frugivore interactions and the potential consequences for large‐seeded plants of losing the last megafaunal representatives in the Neotropics.
{"title":"The irreplaceable role of surviving megafauna in long‐distance seed dispersal: evidence from an experiment with Neotropical mammals","authors":"Mariano I. Giombini, Diana Pésole, Anuncio Daniel Benítez, Sebastián A. Costa, L. Fernando Foletto, C. Esteban Pizzio, Ana L. Dip Yordanoff, M. Genoveva Gatti, Mario S. Di Bitetti","doi":"10.1111/oik.10488","DOIUrl":"https://doi.org/10.1111/oik.10488","url":null,"abstract":"The downsizing of disperser assemblages by selective defaunation is a worldwide phenomenon thought to have important consequences in animal‐dispersed plants. Numerous large‐seeded Neotropical plants currently depend on the last megafaunal survivors, the large tapirs <jats:italic>Tapirus</jats:italic> spp., and medium‐sized frugivores. The extent to which medium frugivores are functionally equivalent to tapirs remains unresolved. We combined feeding trials, seed dispersal kernel modeling based on seed retention times and animal movement simulation (Levy walks), and germination experiments in a large‐seeded palm to assess the dispersal quality provided by the largest (tapirs) and two medium (foxes and howler monkeys) frugivore species in terms of dispersal distances and gut passage effects on germination. Tapirs retained the seeds in the gut for much longer (mean = 221 hours) than howlers (43 h) and foxes (22 h). Median dispersal distance by tapirs (1252 m) was 14 and 40 times larger than that by foxes (88 m) and howlers (31 m), respectively. The seed dispersal kernel of tapirs showed a 5th percentile value (291 m) larger than the 95th percentiles of foxes (285 m) and howlers (108 m). Manually depulped and gut‐passed seeds germinated in similar proportions, showing, respectively, 3.5 and 2.5–2.9 times higher values than intact fruits. Germination probability and seed viability decreased with retention time in howlers' and tapirs' gut, with howlers showing a steeper negative relationship. Such detrimental effect implies a trade‐off between germination success and dispersal distance. We conclude that tapirs may not play a unique role in germination enhancement but move seeds much further than medium frugivores, thus playing a critical role as long‐distance dispersers of many plants. This study provides important insights on palm–frugivore interactions and the potential consequences for large‐seeded plants of losing the last megafaunal representatives in the Neotropics.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"206 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512070","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}
J. Ignacio Ramirez, Maja Sundqvist, Elin Lindén, Robert G. Björk, Bruce C. Forbes, Otso Suominen, Torbjörn Tyler, Risto Virtanen, Johan Olofsson
Herbivores drive shifts in plant species composition by interacting with vegetation through defoliation, trampling and nutrient addition: urine and faeces. As herbivore effects on vegetation accumulate over time, they might spillover to other trophic levels, but how and when this happens is poorly understood. Since it is methodologically demanding to measure biodiversity across spatial gradients, an alternative approach is to assess it through biodiversity indices of vascular plants. We employed the Index of biodiversity relevance developed for Swedish flora which provides an estimated number of organisms associated with a plant species, allowing the quantification of trophic community size. Values from this index were coupled with vegetation data from a network of 96 fenced and paired grazed plots across Fennoscandia. We analysed the role herbivory has on plant richness and diversity, and on the number of organisms that interact with the vegetation according to the index values. We also explored how herbivores influence the competitive effects of tall shrubs on other plants since the dominance of a vegetation type links directly to biodiversity. Plant diversity had no clear response to grazing. Overall vegetation and the vegetation subgroups herbs and non‐fruit shrubs had higher biodiversity index values in fenced plots, indicating a higher number of plant–host interactions. Herb cover was negatively related to shrubs in both treatments but with a faster decline in the absence of herbivores. This study highlights the importance of maintaining herbivore populations in the Arctic to conserve the vegetation structure and biodiversity of the tundra. This method of coupling biodiversity indexes with vegetation data provides complementary information to the plant diversity, especially when methodological or time constraints prevent complete field inventories.
{"title":"Reindeer grazing reduces climate‐driven vegetation changes and shifts trophic interactions in the Fennoscandian tundra","authors":"J. Ignacio Ramirez, Maja Sundqvist, Elin Lindén, Robert G. Björk, Bruce C. Forbes, Otso Suominen, Torbjörn Tyler, Risto Virtanen, Johan Olofsson","doi":"10.1111/oik.10595","DOIUrl":"https://doi.org/10.1111/oik.10595","url":null,"abstract":"Herbivores drive shifts in plant species composition by interacting with vegetation through defoliation, trampling and nutrient addition: urine and faeces. As herbivore effects on vegetation accumulate over time, they might spillover to other trophic levels, but how and when this happens is poorly understood. Since it is methodologically demanding to measure biodiversity across spatial gradients, an alternative approach is to assess it through biodiversity indices of vascular plants. We employed the Index of biodiversity relevance developed for Swedish flora which provides an estimated number of organisms associated with a plant species, allowing the quantification of trophic community size. Values from this index were coupled with vegetation data from a network of 96 fenced and paired grazed plots across Fennoscandia. We analysed the role herbivory has on plant richness and diversity, and on the number of organisms that interact with the vegetation according to the index values. We also explored how herbivores influence the competitive effects of tall shrubs on other plants since the dominance of a vegetation type links directly to biodiversity. Plant diversity had no clear response to grazing. Overall vegetation and the vegetation subgroups herbs and non‐fruit shrubs had higher biodiversity index values in fenced plots, indicating a higher number of plant–host interactions. Herb cover was negatively related to shrubs in both treatments but with a faster decline in the absence of herbivores. This study highlights the importance of maintaining herbivore populations in the Arctic to conserve the vegetation structure and biodiversity of the tundra. This method of coupling biodiversity indexes with vegetation data provides complementary information to the plant diversity, especially when methodological or time constraints prevent complete field inventories.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"12 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512071","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}
Jesse Jorna, Byron J. Adams, Zachary T. Aanderud, Paul B. Frandsen, Cristina Takacs‐Vesbach, Sonia Kéfi
Our understanding of the fundamental role that soil bacteria play in the structure and functioning of Earth's ecosystems is ever expanding, but insight into the nature of interactions within these bacterial communities remains rudimentary. Bacterial facilitation may enhance the establishment, growth, and succession of eukaryotic biota, elevating the complexity and diversity of the entire soil community and thereby modulating multiple ecosystem functions. Global climate change often alters soil bacterial community composition, which, in turn, impacts other dependent biota. However, the impact of climate change on facilitation within bacterial communities remains poorly understood even though it may have important cascading consequences for entire ecosystems. The wealth of metagenomic data currently being generated gives community ecologists the ability to investigate bacterial facilitation in the natural world and how it affects ecological systems responses to climate change. Here, we review current evidence demonstrating the importance of facilitation in promoting emergent properties such as community diversity, ecosystem functioning, and resilience to climate change in soil bacterial communities. We show that a synthesis is currently missing between the abundant data, newly developed models and a coherent ecological framework that addresses these emergent properties. We highlight that including phylogenetic information, the physicochemical environment, and species‐specific ecologies can improve our ability to infer interactions in natural soil communities. Following these recommendations, studies on bacterial facilitation will be an important piece of the puzzle to understand the consequences of global change on ecological communities and a model to advance our understanding of facilitation in complex communities more generally.
{"title":"The underground network: facilitation in soil bacteria","authors":"Jesse Jorna, Byron J. Adams, Zachary T. Aanderud, Paul B. Frandsen, Cristina Takacs‐Vesbach, Sonia Kéfi","doi":"10.1111/oik.10299","DOIUrl":"https://doi.org/10.1111/oik.10299","url":null,"abstract":"Our understanding of the fundamental role that soil bacteria play in the structure and functioning of Earth's ecosystems is ever expanding, but insight into the nature of interactions within these bacterial communities remains rudimentary. Bacterial facilitation may enhance the establishment, growth, and succession of eukaryotic biota, elevating the complexity and diversity of the entire soil community and thereby modulating multiple ecosystem functions. Global climate change often alters soil bacterial community composition, which, in turn, impacts other dependent biota. However, the impact of climate change on facilitation within bacterial communities remains poorly understood even though it may have important cascading consequences for entire ecosystems. The wealth of metagenomic data currently being generated gives community ecologists the ability to investigate bacterial facilitation in the natural world and how it affects ecological systems responses to climate change. Here, we review current evidence demonstrating the importance of facilitation in promoting emergent properties such as community diversity, ecosystem functioning, and resilience to climate change in soil bacterial communities. We show that a synthesis is currently missing between the abundant data, newly developed models and a coherent ecological framework that addresses these emergent properties. We highlight that including phylogenetic information, the physicochemical environment, and species‐specific ecologies can improve our ability to infer interactions in natural soil communities. Following these recommendations, studies on bacterial facilitation will be an important piece of the puzzle to understand the consequences of global change on ecological communities and a model to advance our understanding of facilitation in complex communities more generally.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"16 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512072","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}
Anderson Dantas, Thais A. Vitoriano Dantas, Gislene Ganade, Carlos Roberto Fonseca
The global loss of plant diversity is expected to have reverberating effects on other trophic levels, affecting the structure and functioning of ecosystems. To understand such effects, biodiversity–ecosystem function (BEF) experiments that manipulate tree diversity have been established around the world. In a BEF experiment carried out since 2016 in a seasonally dry tropical forest, we examined the effects of tree diversity, facilitation and density of trees with extrafloral nectaries on the abundance, richness, functional diversity and phylogenetic diversity of ground ants. Also, we used artificial seeds to test seed dispersal efficiency of ants within the experiment. Generalized linear mixed models (GLMM) showed that tree richness positively affects ant abundance, richness, functional diversity and phylogenetic diversity. Also, tree richness had a strong positive effect on the proportion of dispersed seeds, as well as their dispersal distance. Contrary to our expectations, facilitation and the number of trees with extrafloral nectaries did not affect ground ants and their functions. Our results indicate that the global impoverishment of tree communities can affect several dimensions of ant diversity and their ecosystem functions, including forest regeneration processes.
{"title":"Tree richness affects ground‐ant diversity and seed dispersal in a tropical biodiversity–ecosystem function experiment","authors":"Anderson Dantas, Thais A. Vitoriano Dantas, Gislene Ganade, Carlos Roberto Fonseca","doi":"10.1111/oik.10623","DOIUrl":"https://doi.org/10.1111/oik.10623","url":null,"abstract":"The global loss of plant diversity is expected to have reverberating effects on other trophic levels, affecting the structure and functioning of ecosystems. To understand such effects, biodiversity–ecosystem function (BEF) experiments that manipulate tree diversity have been established around the world. In a BEF experiment carried out since 2016 in a seasonally dry tropical forest, we examined the effects of tree diversity, facilitation and density of trees with extrafloral nectaries on the abundance, richness, functional diversity and phylogenetic diversity of ground ants. Also, we used artificial seeds to test seed dispersal efficiency of ants within the experiment. Generalized linear mixed models (GLMM) showed that tree richness positively affects ant abundance, richness, functional diversity and phylogenetic diversity. Also, tree richness had a strong positive effect on the proportion of dispersed seeds, as well as their dispersal distance. Contrary to our expectations, facilitation and the number of trees with extrafloral nectaries did not affect ground ants and their functions. Our results indicate that the global impoverishment of tree communities can affect several dimensions of ant diversity and their ecosystem functions, including forest regeneration processes.","PeriodicalId":19496,"journal":{"name":"Oikos","volume":"77 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189906","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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