Pub Date : 2024-03-19DOI: 10.1017/s026646742400004x
Valentina Posse-Sarmiento, Cristina Banks-Leite
Edge effects change biodiversity patterns and ecological processes, particularly in tropical forests. To understand the synergistic impact of multiple edges, this study examines how edge influence (EI) is associated with life-history traits (snout-vent length and body temperature), diversity and microhabitat of amphibians as well as habitat characteristics in a tropical forest in Ecuador. We used EI, a metric that calculates cumulative effects across all nearby edges, in combination with five environmental variables that are part of the amphibians’ microhabitat (temperature, humidity, slope, canopy cover and leaf litter depth) to understand how their biodiversity patterns are impacted. Our results show that most amphibian species tend to be habitat specialists, and many had an affinity for forest edges and warmer habitats. We do not find significant correlations between EI and amphibian life-history traits and diversity. Our findings corroborate previous results that many amphibian species tend to be positively associated with habitat fragmentation and show that this association is likely driven by thermal regulation.
边缘效应会改变生物多样性模式和生态过程，尤其是在热带森林中。为了了解多重边缘的协同影响，本研究考察了边缘影响（EI）与厄瓜多尔热带森林中两栖动物的生活史特征（鼻孔长度和体温）、多样性和微生境以及生境特征之间的关系。我们使用 EI（一种计算附近所有边缘累积效应的指标）结合两栖动物微生境的五个环境变量（温度、湿度、坡度、树冠覆盖率和落叶深度）来了解两栖动物的生物多样性模式是如何受到影响的。我们的研究结果表明，大多数两栖动物物种往往是栖息地专家，许多物种对森林边缘和较温暖的栖息地情有独钟。我们没有发现 EI 与两栖动物的生活史特征和多样性之间存在明显的相关性。我们的研究结果证实了之前的研究结果，即许多两栖动物物种往往与生境破碎化呈正相关，并表明这种相关性可能是由热调节驱动的。
{"title":"The effects of edge influence on the microhabitat, diversity and life-history traits of amphibians in western Ecuador","authors":"Valentina Posse-Sarmiento, Cristina Banks-Leite","doi":"10.1017/s026646742400004x","DOIUrl":"https://doi.org/10.1017/s026646742400004x","url":null,"abstract":"Edge effects change biodiversity patterns and ecological processes, particularly in tropical forests. To understand the synergistic impact of multiple edges, this study examines how edge influence (EI) is associated with life-history traits (snout-vent length and body temperature), diversity and microhabitat of amphibians as well as habitat characteristics in a tropical forest in Ecuador. We used EI, a metric that calculates cumulative effects across all nearby edges, in combination with five environmental variables that are part of the amphibians’ microhabitat (temperature, humidity, slope, canopy cover and leaf litter depth) to understand how their biodiversity patterns are impacted. Our results show that most amphibian species tend to be habitat specialists, and many had an affinity for forest edges and warmer habitats. We do not find significant correlations between EI and amphibian life-history traits and diversity. Our findings corroborate previous results that many amphibian species tend to be positively associated with habitat fragmentation and show that this association is likely driven by thermal regulation.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"24 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140171840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Oceanic islands, due to their evolutionary history and isolation, play a dual role of having high endemicity and being vulnerable to extinctions, with most known extinctions occurring on islands. Plant–animal interactions are particularly important on islands, as island systems generally have low redundancy and are more vulnerable to disruption either via extinction or by invasive species. Here, we examined the fruit removal and seed predation of a keystone palm, Caryota mitis, on Narcondam, a remote oceanic island. The island endemic Narcondam Hornbill (Rhyticeros narcondami) was the sole seed disperser of the palm (90 hours; N = 15 trees), with mean (± SE) visitation rate being 0.23 (± 0.06) individuals per hour and fruit removal rates of 3.5 (± 1.5; range: 0–16) fruits per visit, indicating a lack of redundancy in seed dispersal of the palm on this island. Whereas the invasive rodent, Rattus cf. tiomanicus, was the sole predator of palm seeds (N = 15 individual fruiting palms, 416 trap nights). Overall, 17.1% of the seeds placed (N = 375 seeds) were removed. Seeds placed under and away from the canopy, and at different densities (2 plots with 10 seeds each; 1 plot with 5 seeds, respectively), showed similar removal rates. This indicates density-independent seed predation and the lack of safe regeneration sites for Caryota mitis, with potential deleterious effects on subsequent stages of the ‘seed dispersal cycle’. Here, from a data-deficient site, we provide baseline information on the plant–frugivore interaction of a keystone palm and the potential impacts of an invasive rodent.
{"title":"Frugivory and seed predation of fishtail palm (Caryota mitis Lour.) on the remote oceanic island of Narcondam, India","authors":"Abhishek Gopal, Sartaj Ghuman, Vivek Ramachandran, Navendu Page, Rohit Naniwadekar","doi":"10.1017/s0266467424000038","DOIUrl":"https://doi.org/10.1017/s0266467424000038","url":null,"abstract":"Oceanic islands, due to their evolutionary history and isolation, play a dual role of having high endemicity and being vulnerable to extinctions, with most known extinctions occurring on islands. Plant–animal interactions are particularly important on islands, as island systems generally have low redundancy and are more vulnerable to disruption either via extinction or by invasive species. Here, we examined the fruit removal and seed predation of a keystone palm, <jats:italic>Caryota mitis</jats:italic>, on Narcondam, a remote oceanic island. The island endemic Narcondam Hornbill (<jats:italic>Rhyticeros narcondami</jats:italic>) was the sole seed disperser of the palm (90 hours; <jats:italic>N</jats:italic> = 15 trees), with mean (± SE) visitation rate being 0.23 (± 0.06) individuals per hour and fruit removal rates of 3.5 (± 1.5; range: 0–16) fruits per visit, indicating a lack of redundancy in seed dispersal of the palm on this island. Whereas the invasive rodent, <jats:italic>Rattus</jats:italic> cf. <jats:italic>tiomanicus</jats:italic>, was the sole predator of palm seeds (<jats:italic>N</jats:italic> = 15 individual fruiting palms, 416 trap nights). Overall, 17.1% of the seeds placed (<jats:italic>N</jats:italic> = 375 seeds) were removed. Seeds placed under and away from the canopy, and at different densities (2 plots with 10 seeds each; 1 plot with 5 seeds, respectively), showed similar removal rates. This indicates density-independent seed predation and the lack of safe regeneration sites for <jats:italic>Caryota mitis</jats:italic>, with potential deleterious effects on subsequent stages of the ‘seed dispersal cycle’. Here, from a data-deficient site, we provide baseline information on the plant–frugivore interaction of a keystone palm and the potential impacts of an invasive rodent.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"36 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140105994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-02-12DOI: 10.1017/s0266467424000026
Aloysius Teo, Theodore A. Evans, Ryan A. Chisholm
The estimation of leaf litter turnover is often limited to early-stage decomposition using unrepresentative models and litter types. In tropical secondary forests, particularly exotic-dominated novel forests, the characterisation of litter turnover remains poor. This study estimated the annual turnover of in-situ leaf litter across four forest successional types in Singapore using a Weibull residence time model. Litter turnover and nutrient dynamics diverged between young secondary and old-growth forests. In particular, within novel forests, annual phosphorus return via leaf litterfall was three times that of primary forests, while the mass loss of in-situ leaf litter was highest among all forest successional types, estimated at 92.8% annually with a mean residence time of 176 days, resulting in a litter pool size a third that of primary forests. Our findings suggest that tree species composition and species-specific effects shaped the observed variations in litter turnover and nutrient dynamics across forest successional types and forest stands, whereas tree species richness, canopy structure, soil nutrient levels, and microclimate were found to be non-predictors. Taken together, our study provides an insight into litter turnover in human-modified tropical landscapes increasingly characterised by novel forests, potentially leading to a reduction in surface litter and soil organic carbon pools.
{"title":"Elevated litterfall phosphorus reduces litter and soil organic matter pools in exotic-dominated novel forests in Singapore","authors":"Aloysius Teo, Theodore A. Evans, Ryan A. Chisholm","doi":"10.1017/s0266467424000026","DOIUrl":"https://doi.org/10.1017/s0266467424000026","url":null,"abstract":"The estimation of leaf litter turnover is often limited to early-stage decomposition using unrepresentative models and litter types. In tropical secondary forests, particularly exotic-dominated novel forests, the characterisation of litter turnover remains poor. This study estimated the annual turnover of <jats:italic>in-situ</jats:italic> leaf litter across four forest successional types in Singapore using a Weibull residence time model. Litter turnover and nutrient dynamics diverged between young secondary and old-growth forests. In particular, within novel forests, annual phosphorus return via leaf litterfall was three times that of primary forests, while the mass loss of <jats:italic>in-situ</jats:italic> leaf litter was highest among all forest successional types, estimated at 92.8% annually with a mean residence time of 176 days, resulting in a litter pool size a third that of primary forests. Our findings suggest that tree species composition and species-specific effects shaped the observed variations in litter turnover and nutrient dynamics across forest successional types and forest stands, whereas tree species richness, canopy structure, soil nutrient levels, and microclimate were found to be non-predictors. Taken together, our study provides an insight into litter turnover in human-modified tropical landscapes increasingly characterised by novel forests, potentially leading to a reduction in surface litter and soil organic carbon pools.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"18 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139752067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Functional diversity indices have been used to differentiate the relative contribution of stochastic and deterministic processes that modulate the assemblage of communities; however, knowledge regarding the relative contribution of assemblage mechanisms in forest communities is scarce. We analysed the assembly mechanisms driving forest assemblages along a topographic gradient at two spatial scales (1000 m2 and 3000 m2) for three different forest types from subtropical mountain forests (pine-oak, mixed pine-broadleaf and broadleaf forest) in western Mexico, using null models of multi-trait indices. The forest structure differed along the topographic gradient. Upper slopes were dominated by Pinus douglasiana with an importance value index (IVI) of 0.8, while 10 and 13 tree species were required in the middle and lower slopes, respectively, to reach the same IVI. The results support the idea that the subtropical montane forest of western Mexico is a mosaic of communities, when analysed at a scale of 1000 m2 the forest assembly was mainly explained by stochastic processes, while analysis at the scale of 3000 m2 showed that functional convergence of species were the main mechanisms of the assemblage of the pine-oak forest communities due to an abiotic stressful environment.
{"title":"Assemblage of forest communities in subtropical montane forests of western Mexico","authors":"Karolina Riaño, Ramón Cuevas, Susana Zuloaga-Aguilar, Enrique Jardel, Oscar Briones, Heidi Asbjornsen","doi":"10.1017/s0266467424000014","DOIUrl":"https://doi.org/10.1017/s0266467424000014","url":null,"abstract":"Functional diversity indices have been used to differentiate the relative contribution of stochastic and deterministic processes that modulate the assemblage of communities; however, knowledge regarding the relative contribution of assemblage mechanisms in forest communities is scarce. We analysed the assembly mechanisms driving forest assemblages along a topographic gradient at two spatial scales (1000 m<jats:sup>2</jats:sup> and 3000 m<jats:sup>2</jats:sup>) for three different forest types from subtropical mountain forests (pine-oak, mixed pine-broadleaf and broadleaf forest) in western Mexico, using null models of multi-trait indices. The forest structure differed along the topographic gradient. Upper slopes were dominated by <jats:italic>Pinus douglasiana</jats:italic> with an importance value index (IVI) of 0.8, while 10 and 13 tree species were required in the middle and lower slopes, respectively, to reach the same IVI. The results support the idea that the subtropical montane forest of western Mexico is a mosaic of communities, when analysed at a scale of 1000 m<jats:sup>2</jats:sup> the forest assembly was mainly explained by stochastic processes, while analysis at the scale of 3000 m<jats:sup>2</jats:sup> showed that functional convergence of species were the main mechanisms of the assemblage of the pine-oak forest communities due to an abiotic stressful environment.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"136 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139579532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Ribbon worms in the genus Balionemertes from Vietnam, the Philippines, Australia, and Guam—as well as Cephalothrix suni from Vietnam—were examined. Our observations indicate that the worms crawl mostly with their ventral surface upwards (the ventral surface being where the mouth opens), a behaviour that has not been documented in previous literature. Like many other worm species with colour patterns, they have a darker-coloured and/or more intensely patterned behavioural dorsal surface (= anatomical ventral surface in Balionemertes and C. suni) than the other side. This type of behavioural dorsoventral body-axis inversion among vermiform benthos seems to be rare—not having hitherto been known at least in the phylum Nemertea—and may be related to their feeding strategy, which should be observed in future studies.
我们研究了来自越南、菲律宾、澳大利亚和关岛的丝带虫属 Balionemertes 以及来自越南的 Cephalothrix suni。我们的观察结果表明，带状蠕虫主要以腹面向上的方式爬行（腹面是嘴巴张开的地方），这种行为在以前的文献中没有记载。与许多其他有颜色图案的蠕虫物种一样，它们的行为背表面（= Balionemertes 和 C. suni 的解剖腹表面）比另一侧颜色更深和/或图案更密集。在蛭形底栖动物中，这种行为背腹体轴倒置的情况似乎很少见，至少在尼目动物中迄今尚未发现，这可能与它们的摄食策略有关，应在今后的研究中加以观察。
{"title":"Upside-down behaviour of certain ribbon worms (phylum Nemertea)","authors":"Hiroshi Kajihara, Audrey Falconer, Alexei Viktorovich Chernyshev","doi":"10.1017/s0266467423000330","DOIUrl":"https://doi.org/10.1017/s0266467423000330","url":null,"abstract":"Ribbon worms in the genus <jats:italic>Balionemertes</jats:italic> from Vietnam, the Philippines, Australia, and Guam—as well as <jats:italic>Cephalothrix suni</jats:italic> from Vietnam—were examined. Our observations indicate that the worms crawl mostly with their ventral surface upwards (the ventral surface being where the mouth opens), a behaviour that has not been documented in previous literature. Like many other worm species with colour patterns, they have a darker-coloured and/or more intensely patterned behavioural dorsal surface (= anatomical ventral surface in <jats:italic>Balionemertes</jats:italic> and <jats:italic>C</jats:italic>. <jats:italic>suni</jats:italic>) than the other side. This type of behavioural dorsoventral body-axis inversion among vermiform benthos seems to be rare—not having hitherto been known at least in the phylum Nemertea—and may be related to their feeding strategy, which should be observed in future studies.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"649 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139104247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-01-04DOI: 10.1017/s0266467423000329
Susana Ruiz-Díaz, Lidia Florencia Pérez de Molas, Enrique Benítez-León, Angélica María Almeyda Zambrano, Daniel J. Johnson, Stephanie Bohlman, Eben North Broadbent
One of the largest remnants of tropical dry forest is the South American Gran Chaco. A quarter of this biome is in Paraguay, but there have been few studies in the Paraguayan Chaco. The Gran Chaco flora is diverse in structure, function, composition and phenology. Fundamental ecological questions remain in this biome, such as what bioclimatic factors shape the Chaco’s composition, structure and phenology. In this study, we integrated forest inventories from permanent plots with monthly high-resolution NDVI from PlanetScope and historical climate data from WorldClim to identify bioclimatic predictors of forest structure, composition and phenology. We found that bioclimatic variables related to precipitation were correlated with stem density and Pielou evenness index, while temperature-related variables correlated with basal area. The best predictor of forest phenology (NDVI variation) was precipitation lagged by 1 month followed by temperature lagged by 2 months. In the period with most water stress, the phenological response correlates with diversity, height and basal area, showing links with dominance and tree size. Our results indicate that even if the ecology and function of Dry Chaco Forest is characterised by water limitation, temperature has a moderating effect by limiting growth and influencing leaf flush and deciduousness.
{"title":"Bioclimatic predictors of forest structure, composition and phenology in the Paraguayan Dry Chaco","authors":"Susana Ruiz-Díaz, Lidia Florencia Pérez de Molas, Enrique Benítez-León, Angélica María Almeyda Zambrano, Daniel J. Johnson, Stephanie Bohlman, Eben North Broadbent","doi":"10.1017/s0266467423000329","DOIUrl":"https://doi.org/10.1017/s0266467423000329","url":null,"abstract":"One of the largest remnants of tropical dry forest is the South American Gran Chaco. A quarter of this biome is in Paraguay, but there have been few studies in the Paraguayan Chaco. The Gran Chaco flora is diverse in structure, function, composition and phenology. Fundamental ecological questions remain in this biome, such as what bioclimatic factors shape the Chaco’s composition, structure and phenology. In this study, we integrated forest inventories from permanent plots with monthly high-resolution NDVI from PlanetScope and historical climate data from WorldClim to identify bioclimatic predictors of forest structure, composition and phenology. We found that bioclimatic variables related to precipitation were correlated with stem density and Pielou evenness index, while temperature-related variables correlated with basal area. The best predictor of forest phenology (NDVI variation) was precipitation lagged by 1 month followed by temperature lagged by 2 months. In the period with most water stress, the phenological response correlates with diversity, height and basal area, showing links with dominance and tree size. Our results indicate that even if the ecology and function of Dry Chaco Forest is characterised by water limitation, temperature has a moderating effect by limiting growth and influencing leaf flush and deciduousness.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"19 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139104571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2023-12-04DOI: 10.1017/s0266467423000251
Ireri Suazo-Ortuño, Julieta Benítez-Malvido, Marco Tulio Oropeza-Sánchez
Flagship species are those chosen to raise support for broader conservation marketing campaigns and can be used as symbols of the ecosystem services and evolutionary history of particular areas. Thus, flagship species can be employed for the protection of endangered species and threatened ecosystems. Northeastern Michoacán, Mexico, is an important region for amphibian diversity but approximately 40% of its mature forest has been removed. Among northeastern Michoacán amphibians, the use of Ambystoma ordinarium as a flagship species is supported by its co-occurrence with other threatened amphibians along riparian zones. To support this proposal, however, it is important to assess the functional traits and evolutionary history of amphibian species sharing their habitat with A. ordinarium. To evaluate the potential of A. ordinarium as a flagship species, we estimated the functional and phylogenetic diversity of amphibian assemblages in 60 riparian zones. The results showed that amphibian assemblages sharing habitat with A. ordinarium presented higher functional and phylogenetic diversity than those in which this species was absent. These results highlight the potential of A. ordinarium as a flagship species for the protection of associated amphibian species, their functions, and evolutionary history.
{"title":"Functional and phylogenetic metrics to evaluate the potential of flagship species: the case of the salamander Ambystoma ordinarium","authors":"Ireri Suazo-Ortuño, Julieta Benítez-Malvido, Marco Tulio Oropeza-Sánchez","doi":"10.1017/s0266467423000251","DOIUrl":"https://doi.org/10.1017/s0266467423000251","url":null,"abstract":"Flagship species are those chosen to raise support for broader conservation marketing campaigns and can be used as symbols of the ecosystem services and evolutionary history of particular areas. Thus, flagship species can be employed for the protection of endangered species and threatened ecosystems. Northeastern Michoacán, Mexico, is an important region for amphibian diversity but approximately 40% of its mature forest has been removed. Among northeastern Michoacán amphibians, the use of <jats:italic>Ambystoma ordinarium</jats:italic> as a flagship species is supported by its co-occurrence with other threatened amphibians along riparian zones. To support this proposal, however, it is important to assess the functional traits and evolutionary history of amphibian species sharing their habitat with <jats:italic>A. ordinarium</jats:italic>. To evaluate the potential of <jats:italic>A. ordinarium</jats:italic> as a flagship species, we estimated the functional and phylogenetic diversity of amphibian assemblages in 60 riparian zones. The results showed that amphibian assemblages sharing habitat with <jats:italic>A. ordinarium</jats:italic> presented higher functional and phylogenetic diversity than those in which this species was absent. These results highlight the potential of <jats:italic>A. ordinarium</jats:italic> as a flagship species for the protection of associated amphibian species, their functions, and evolutionary history.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"159 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138533521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2023-12-01DOI: 10.1017/s0266467423000305
Michelle E. Thompson, Maureen A. Donnelly
The extensive clearing and modification of forests by anthropogenic activities is a major driver of biodiversity loss. Declines of common species are especially concerning because of the potentially large cascading effects they might have on ecosystems. Regrowth of secondary forests may help reverse population declines by restoring habitats to similar conditions prior to land conversion but the value of these secondary forests to fauna is not well understood. We compared the abundance of a direct-developing terrestrial frog, Craugastor stejnegerianus, in riparian and upland habitats of pasture, secondary forest, and mature forest sites. Mean abundance per transect was lower in upland pasture compared to mature forest. Secondary forest had similar abundance to mature forest regardless of age. We show that conversion of forest habitat to pasture represents a conservation threat to this species. However, riparian buffers help mitigate the negative effect of conversion of forest to pasture, and regrowth of secondary forest is an effective management strategy for restoring the abundance of this common leaf-litter species.
{"title":"Leaf-litter frog abundance increases during succession of regenerating pastures","authors":"Michelle E. Thompson, Maureen A. Donnelly","doi":"10.1017/s0266467423000305","DOIUrl":"https://doi.org/10.1017/s0266467423000305","url":null,"abstract":"The extensive clearing and modification of forests by anthropogenic activities is a major driver of biodiversity loss. Declines of common species are especially concerning because of the potentially large cascading effects they might have on ecosystems. Regrowth of secondary forests may help reverse population declines by restoring habitats to similar conditions prior to land conversion but the value of these secondary forests to fauna is not well understood. We compared the abundance of a direct-developing terrestrial frog, <jats:italic>Craugastor stejnegerianus</jats:italic>, in riparian and upland habitats of pasture, secondary forest, and mature forest sites. Mean abundance per transect was lower in upland pasture compared to mature forest. Secondary forest had similar abundance to mature forest regardless of age. We show that conversion of forest habitat to pasture represents a conservation threat to this species. However, riparian buffers help mitigate the negative effect of conversion of forest to pasture, and regrowth of secondary forest is an effective management strategy for restoring the abundance of this common leaf-litter species.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138533520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2023-12-01DOI: 10.1017/s0266467423000317
Juan Carlos Vargas-Mena, Eugenia Cordero-Schmidt, Bernal Rodríguez-Herrera, Eduardo Martins Venticinque
The Caatinga is the largest seasonal tropical dry forest with extreme environmental and meteorological conditions. It harbours many phytophysiognomies and vegetational units, but bat fauna is poorly known in many regions. We analysed the structure of bat assemblages by mist-netting during 99 nights in seven habitats throughout six sites in the northeasternmost region of the Caatinga in Rio Grande do Norte State, in the Brazilian northeast. With a sampling effort of 239 665 m2h, we captured 1575 individuals of 31 species of bats. Bat assemblages’ structure and species distribution changed according to the habitat type, and differences in richness, abundance, species composition, and trophic guild representation were found. The frugivore A. planirostris was widespread, and its superabundance hold for all habitats. The distinct array of the most abundant species with several exclusive species in each habitat suggests species- and trophic guild-specific preferences to particular habitats. Differences in the structure of bat assemblages may be driven by each habitat’s vegetational structure and plant composition (e.g., semi-open habitats vs. tall forest stands) that offers distinct exploitable resources (e.g., food and roosts). Finally, we discuss the importance of foraging habitats for the conservation of these unique bat assemblages in the northeasternmost region of the Caatinga dry forest.
{"title":"Differences in the structure of bat assemblages among habitats in the Caatinga dry forest","authors":"Juan Carlos Vargas-Mena, Eugenia Cordero-Schmidt, Bernal Rodríguez-Herrera, Eduardo Martins Venticinque","doi":"10.1017/s0266467423000317","DOIUrl":"https://doi.org/10.1017/s0266467423000317","url":null,"abstract":"The Caatinga is the largest seasonal tropical dry forest with extreme environmental and meteorological conditions. It harbours many phytophysiognomies and vegetational units, but bat fauna is poorly known in many regions. We analysed the structure of bat assemblages by mist-netting during 99 nights in seven habitats throughout six sites in the northeasternmost region of the Caatinga in Rio Grande do Norte State, in the Brazilian northeast. With a sampling effort of 239 665 m2h, we captured 1575 individuals of 31 species of bats. Bat assemblages’ structure and species distribution changed according to the habitat type, and differences in richness, abundance, species composition, and trophic guild representation were found. The frugivore <jats:italic>A. planirostris</jats:italic> was widespread, and its superabundance hold for all habitats. The distinct array of the most abundant species with several exclusive species in each habitat suggests species- and trophic guild-specific preferences to particular habitats. Differences in the structure of bat assemblages may be driven by each habitat’s vegetational structure and plant composition (e.g., semi-open habitats vs. tall forest stands) that offers distinct exploitable resources (e.g., food and roosts). Finally, we discuss the importance of foraging habitats for the conservation of these unique bat assemblages in the northeasternmost region of the Caatinga dry forest.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"29 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138533525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2023-09-01DOI: 10.1017/S0266467423000226
F. Vencl, Robert B. Srygley
Abstract Little is known about the effects of El Niño-Southern Oscillation (ENSO) on tropical insect communities, even though they are suffering rapid declines in complexity and stability due to climate change. We explore the impact of fluctuations in local climate imposed by ENSO on the performance of herbivore defences mediating enemy interactions. In a widespread rainforest edge community, we quantified the mortality caused by five enemy guilds on the immature stages of the herbivorous beetle, Acromis sparsa. ENSO was a significant determinant of beetle mortality. During warmer, drier El Niño years, the survival of beetles decreased. This was due to increased egg parasitism by wasps, which reduced hatching. Additionally, ant predation on beetle larvae increased. Flies and wasps were in competition for larval prey in wetter, cooler La Niña years. Experimental removal of maternal guards or chemical shields revealed which ENSO-related parameters predicted larval mortality. Guarding was most effective against social wasps in La Niña, whereas shields proved most effective in El Niño. Two ENSO-related defence–enemy breakdowns occurred: (1) decoupling whereby the efficacy of a narrow defensive adaptation was reduced to increase mortality, and (2) mismatching whereby the resistance of a narrow defensive adaptation against non-targeted enemies was further reduced to increase mortality. These results highlight that defence efficacy against natural enemies can vary predictably with biotic and abiotic environmental conditions. ENSO events will increase breakdowns in defence-mediated interactions, shifts in competition among enemies, and species loss.
{"title":"El Niño oscillations impact anti-predator defences to alter survival of an herbivorous beetle in a neotropical wet forest","authors":"F. Vencl, Robert B. Srygley","doi":"10.1017/S0266467423000226","DOIUrl":"https://doi.org/10.1017/S0266467423000226","url":null,"abstract":"Abstract Little is known about the effects of El Niño-Southern Oscillation (ENSO) on tropical insect communities, even though they are suffering rapid declines in complexity and stability due to climate change. We explore the impact of fluctuations in local climate imposed by ENSO on the performance of herbivore defences mediating enemy interactions. In a widespread rainforest edge community, we quantified the mortality caused by five enemy guilds on the immature stages of the herbivorous beetle, Acromis sparsa. ENSO was a significant determinant of beetle mortality. During warmer, drier El Niño years, the survival of beetles decreased. This was due to increased egg parasitism by wasps, which reduced hatching. Additionally, ant predation on beetle larvae increased. Flies and wasps were in competition for larval prey in wetter, cooler La Niña years. Experimental removal of maternal guards or chemical shields revealed which ENSO-related parameters predicted larval mortality. Guarding was most effective against social wasps in La Niña, whereas shields proved most effective in El Niño. Two ENSO-related defence–enemy breakdowns occurred: (1) decoupling whereby the efficacy of a narrow defensive adaptation was reduced to increase mortality, and (2) mismatching whereby the resistance of a narrow defensive adaptation against non-targeted enemies was further reduced to increase mortality. These results highlight that defence efficacy against natural enemies can vary predictably with biotic and abiotic environmental conditions. ENSO events will increase breakdowns in defence-mediated interactions, shifts in competition among enemies, and species loss.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48251104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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