Pub Date : 2022-05-16DOI: 10.1017/s0266467422000220
A. C. L. Araújo, B. Bezerra, I. M. S. Lima, L. B. Oliveira-Silva, Anielise C. Campêlo, J. P. Souza‐Alves
Understanding how and why exotic species use their habitats is crucial for defining effective conservation strategies. We aimed to investigate habitat use by an exotic population of squirrel monkeys living in an Atlantic Forest fragment and identify factors associated with their habitat preferences. Over 6 months of scan sampling observations, we collected data on native and exotic plants consumed by the squirrel monkeys, food availability, and interactions between the squirrel monkeys and the native common marmosets. We also georeferenced the estimated centroid point of the study group during each scan. Squirrel monkeys used Secondary Old Forest habitats more often than the other habitats available. The consumption of native and exotic plants and the association with common marmoset appear to have influenced the habitat use of the exotic squirrel monkeys; however, the choice habitat did not demonstrate to be associated with food availability. The exotic squirrel monkeys preferred to use less disturbed habitats to consume a high amount of food (often associated with the common marmoset), potentially optimizing their food intake. Our findings demonstrated the adaptive success of an exotic primate in its non-natural habitat and the key role of the plant community in maintaining this population.
{"title":"Plant community and native primate as drivers of habitat use by an exotic primate (Saimiri spp. Linnaeus, 1758) in an Atlantic Forest fragment","authors":"A. C. L. Araújo, B. Bezerra, I. M. S. Lima, L. B. Oliveira-Silva, Anielise C. Campêlo, J. P. Souza‐Alves","doi":"10.1017/s0266467422000220","DOIUrl":"https://doi.org/10.1017/s0266467422000220","url":null,"abstract":"\u0000 Understanding how and why exotic species use their habitats is crucial for defining effective conservation strategies. We aimed to investigate habitat use by an exotic population of squirrel monkeys living in an Atlantic Forest fragment and identify factors associated with their habitat preferences. Over 6 months of scan sampling observations, we collected data on native and exotic plants consumed by the squirrel monkeys, food availability, and interactions between the squirrel monkeys and the native common marmosets. We also georeferenced the estimated centroid point of the study group during each scan. Squirrel monkeys used Secondary Old Forest habitats more often than the other habitats available. The consumption of native and exotic plants and the association with common marmoset appear to have influenced the habitat use of the exotic squirrel monkeys; however, the choice habitat did not demonstrate to be associated with food availability. The exotic squirrel monkeys preferred to use less disturbed habitats to consume a high amount of food (often associated with the common marmoset), potentially optimizing their food intake. Our findings demonstrated the adaptive success of an exotic primate in its non-natural habitat and the key role of the plant community in maintaining this population.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44485174","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 : 2022-05-13DOI: 10.1017/s0266467422000165
Benoit Penel, V. Freycon, Eric Marcon, V. Rossi, Guillaume Cornu, F. Bénédet, É. Forni, S. Gourlet‐Fleury
Termite mounds have been poorly studied in tropical rainforest in contrast to those of savannahs where they create fertility hotspots and influence the spatial pattern of vegetation. An inventory of termite mounds and of 15 tree species with a diameter at breast height ≥ 10 cm was carried out in two 800-ha blocks, in two rainforest sites located in northern Congo. We used inhomogeneous and intertype K functions to study the spatial pattern of termite mounds and of tree species around mounds, respectively. We found that mounds in Loundoungou were over-dispersed within a radius of less than 70 m, while those in Mokabi were randomly spaced. Tree species within a 20-m radius around a mound were aggregated towards the mound, e.g. Entandrophragma cylindricum, randomly distributed, or even repulsed by the mound. The specific responses also differed in the two sites. These results suggest that (i) the mounds in Loundoungou were created by savannah termite species 3,000-2,000 years BP during the Late Holocene Rainforest Crisis and (ii) the mounds in Mokabi are characteristic of forest mounds. The impact of termite mounds on the spatial pattern of tree species is thus site-dependent, and these differences might be due to species seed dispersal strategies and to soil calcium concentrations.
{"title":"Macrotermes termite mounds influence the spatial pattern of tree species in two African rainforest sites, in northern Congo. But were they really forests in the past?","authors":"Benoit Penel, V. Freycon, Eric Marcon, V. Rossi, Guillaume Cornu, F. Bénédet, É. Forni, S. Gourlet‐Fleury","doi":"10.1017/s0266467422000165","DOIUrl":"https://doi.org/10.1017/s0266467422000165","url":null,"abstract":"\u0000 Termite mounds have been poorly studied in tropical rainforest in contrast to those of savannahs where they create fertility hotspots and influence the spatial pattern of vegetation. An inventory of termite mounds and of 15 tree species with a diameter at breast height ≥ 10 cm was carried out in two 800-ha blocks, in two rainforest sites located in northern Congo. We used inhomogeneous and intertype K functions to study the spatial pattern of termite mounds and of tree species around mounds, respectively. We found that mounds in Loundoungou were over-dispersed within a radius of less than 70 m, while those in Mokabi were randomly spaced. Tree species within a 20-m radius around a mound were aggregated towards the mound, e.g. Entandrophragma cylindricum, randomly distributed, or even repulsed by the mound. The specific responses also differed in the two sites. These results suggest that (i) the mounds in Loundoungou were created by savannah termite species 3,000-2,000 years BP during the Late Holocene Rainforest Crisis and (ii) the mounds in Mokabi are characteristic of forest mounds. The impact of termite mounds on the spatial pattern of tree species is thus site-dependent, and these differences might be due to species seed dispersal strategies and to soil calcium concentrations.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47263078","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 : 2022-05-10DOI: 10.1017/s0266467422000177
M. Kleine, Subhadip Ghosh, E. Leitgeb, A. Berger, H. B. Ibrahim, T. Gschwantner, L. Ow, K. Michel
Land-use changes and forest management decisions can profoundly alter soil organic carbon (SOC) stocks. Therefore, the objective of this study was to investigate whether existing SOC stocks in the forests of Singapore can be related to successional stages of forest vegetation following disturbances. A forest classification system was developed using information about land use history and vegetation data from 21 inventory plots collected within the framework of Singapore’s IPCC-compatible greenhouse gas reporting system. The forest successional classes obtained were related to SOC stocks (0–50 cm) determined on the same plots. The inventory plots were assigned to four classes. Primary forests (Class 1) were dominated by late succession native species. Secondary forests representing natural forest succession (Class 2) contained younger native trees and a few large trees. Secondary forests after tree plantation/fruit orchard (Class 3) and after agricultural crop cultivation (Class 4) were characterised by large proportions of exotic tree species. Maximum stocks of SOC declined from Class 1 (127.7 Mg ha−1) to Class 4 (35.2 Mg ha−1). The results of a principal component analysis confirmed our forest classification. Plant-related parameters can be successfully used to classify the forests in Singapore, which also show clear differences in SOC.
{"title":"Variation in soil organic carbon stocks in Singapore with forest succession and land management","authors":"M. Kleine, Subhadip Ghosh, E. Leitgeb, A. Berger, H. B. Ibrahim, T. Gschwantner, L. Ow, K. Michel","doi":"10.1017/s0266467422000177","DOIUrl":"https://doi.org/10.1017/s0266467422000177","url":null,"abstract":"\u0000 Land-use changes and forest management decisions can profoundly alter soil organic carbon (SOC) stocks. Therefore, the objective of this study was to investigate whether existing SOC stocks in the forests of Singapore can be related to successional stages of forest vegetation following disturbances. A forest classification system was developed using information about land use history and vegetation data from 21 inventory plots collected within the framework of Singapore’s IPCC-compatible greenhouse gas reporting system. The forest successional classes obtained were related to SOC stocks (0–50 cm) determined on the same plots. The inventory plots were assigned to four classes. Primary forests (Class 1) were dominated by late succession native species. Secondary forests representing natural forest succession (Class 2) contained younger native trees and a few large trees. Secondary forests after tree plantation/fruit orchard (Class 3) and after agricultural crop cultivation (Class 4) were characterised by large proportions of exotic tree species. Maximum stocks of SOC declined from Class 1 (127.7 Mg ha−1) to Class 4 (35.2 Mg ha−1). The results of a principal component analysis confirmed our forest classification. Plant-related parameters can be successfully used to classify the forests in Singapore, which also show clear differences in SOC.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42242222","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 : 2022-03-30DOI: 10.1017/s0266467422000104
Tibebu Enkossa, S. Nemomissa, D. Lemessa
Continuing climate change may cause shifts in the adaptive ranges of plant species. But this impact is less understood for many species in the tropics. Here, we examined the distribution of the current and future potential suitable habitats of two native forest spices Piper capense and Aframomum corrorima. We have used MaxEnt software to predict the current and future suitable habitats of these species. Two future climate change scenarios, that is, middle (Representative Concentration Pathway [RCP 4.5]) and extreme (RCP 8.5) scenarios for years 2050 and 2070, were used. A total of 60 and 74 occurrence data of P. capense and A. corrorima, respectively, and 22 environmental variables were included. The effects of elevation, solar radiation index (SRI) and topographic position index (TPI) on suitable habitats of these species were tested using linear model in R. Precipitation of the driest quarter, SRI and TPI significantly affect future suitable habitats of P. capense and A. corrorima. Furthermore, there are significant elevational shifts of suitable habitats for both species under future scenarios (P < 0.001). These novel suitable habitats are located in moist Afromontane and Combretum-Terminalia vegetations. Our results suggest that conservation planning for these species should consider climate change factors including assisted migration.
{"title":"Predicting the potential suitable habitats of forest spices Piper capense and Aframomum corrorima under climate change in Ethiopia","authors":"Tibebu Enkossa, S. Nemomissa, D. Lemessa","doi":"10.1017/s0266467422000104","DOIUrl":"https://doi.org/10.1017/s0266467422000104","url":null,"abstract":"\u0000 Continuing climate change may cause shifts in the adaptive ranges of plant species. But this impact is less understood for many species in the tropics. Here, we examined the distribution of the current and future potential suitable habitats of two native forest spices Piper capense and Aframomum corrorima. We have used MaxEnt software to predict the current and future suitable habitats of these species. Two future climate change scenarios, that is, middle (Representative Concentration Pathway [RCP 4.5]) and extreme (RCP 8.5) scenarios for years 2050 and 2070, were used. A total of 60 and 74 occurrence data of P. capense and A. corrorima, respectively, and 22 environmental variables were included. The effects of elevation, solar radiation index (SRI) and topographic position index (TPI) on suitable habitats of these species were tested using linear model in R. Precipitation of the driest quarter, SRI and TPI significantly affect future suitable habitats of P. capense and A. corrorima. Furthermore, there are significant elevational shifts of suitable habitats for both species under future scenarios (P < 0.001). These novel suitable habitats are located in moist Afromontane and Combretum-Terminalia vegetations. Our results suggest that conservation planning for these species should consider climate change factors including assisted migration.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41702826","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 : 2022-03-29DOI: 10.1017/s0266467422000128
A. Fleischmann, P. Gonella, S. Rojo, X. Mengual
The complete life history of the kleptoparasitic ‘sundew flower fly’, Toxomerus basalis, is presented and illustrated. Adults of this species are photographed alive for the first time, including video recordings of larval and adult behaviour. Adult flies of both sexes visit Drosera (sundews) and show territorial behaviour around the plants, avoiding the dangerous sticky traps and demonstrating recognition of their larval host plant. Females lay eggs directly on non-sticky parts of the Drosera host plants, such as on the lower surface of the leaves and flower stalks, but apparently also on other plants growing in close proximity with the sundews.
{"title":"Attracted to feed, not to be fed upon – on the biology of Toxomerus basalis (Walker, 1836), the kleptoparasitic ‘sundew flower fly’ (Diptera: Syrphidae)","authors":"A. Fleischmann, P. Gonella, S. Rojo, X. Mengual","doi":"10.1017/s0266467422000128","DOIUrl":"https://doi.org/10.1017/s0266467422000128","url":null,"abstract":"\u0000 The complete life history of the kleptoparasitic ‘sundew flower fly’, Toxomerus basalis, is presented and illustrated. Adults of this species are photographed alive for the first time, including video recordings of larval and adult behaviour. Adult flies of both sexes visit Drosera (sundews) and show territorial behaviour around the plants, avoiding the dangerous sticky traps and demonstrating recognition of their larval host plant. Females lay eggs directly on non-sticky parts of the Drosera host plants, such as on the lower surface of the leaves and flower stalks, but apparently also on other plants growing in close proximity with the sundews.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43698623","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 : 2022-03-28DOI: 10.1017/s0266467422000141
S. Jaafar, F. Metali, R. Sukri
Invasive Acacia species are known to modify soil properties, although effects are often site-specific. We examined the impact of Acacia species on the soils of intact and invaded habitats of two contrasting tropical lowland rain forest types in Brunei Darussalam: heath forest (HF) and mixed dipterocarp forest (MDF). Impacts on soil properties differed between the two forest types. Overall, Acacia-invaded HF soil recorded significantly higher gravimetric water content, pH and total P, K and Ca compared to the intact HF soil. In contrast, invaded MDF soil exhibited significantly higher organic matter content and total soil N, P, K and Mg compared to its intact habitat. Acacia-invaded MDF soils were more nutrient-enriched than Acacia-invaded HF soils by the addition of threefold, threefold and fourfold total soil P, K and Mg, respectively. The positive effect of addition of total soil Ca was, however, fourfold greater in HF soil than MDF soil, indicating that the magnitude of impact on soil properties was strongly site-specific. Overall, Acacia invasion significantly impacted soil properties in nutrient-rich MDF more than those of nutrient-poor HFs, indicating a potential vulnerability of MDFs to invasion.
{"title":"Acacia invasion differentially impacts soil properties of two contrasting tropical lowland forests in Brunei Darussalam","authors":"S. Jaafar, F. Metali, R. Sukri","doi":"10.1017/s0266467422000141","DOIUrl":"https://doi.org/10.1017/s0266467422000141","url":null,"abstract":"\u0000 Invasive Acacia species are known to modify soil properties, although effects are often site-specific. We examined the impact of Acacia species on the soils of intact and invaded habitats of two contrasting tropical lowland rain forest types in Brunei Darussalam: heath forest (HF) and mixed dipterocarp forest (MDF). Impacts on soil properties differed between the two forest types. Overall, Acacia-invaded HF soil recorded significantly higher gravimetric water content, pH and total P, K and Ca compared to the intact HF soil. In contrast, invaded MDF soil exhibited significantly higher organic matter content and total soil N, P, K and Mg compared to its intact habitat. Acacia-invaded MDF soils were more nutrient-enriched than Acacia-invaded HF soils by the addition of threefold, threefold and fourfold total soil P, K and Mg, respectively. The positive effect of addition of total soil Ca was, however, fourfold greater in HF soil than MDF soil, indicating that the magnitude of impact on soil properties was strongly site-specific. Overall, Acacia invasion significantly impacted soil properties in nutrient-rich MDF more than those of nutrient-poor HFs, indicating a potential vulnerability of MDFs to invasion.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42151813","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 : 2022-03-25DOI: 10.1017/s0266467421000481
D. R. Souza-Campana, Rogério R. Silva, O. Fernandes, Bianca Sayuri Futikami, O. Bueno, Luan Alberto Odorizzi Santos, M. Morini
In this study, we compared the richness of ground-dwelling ants among three different sugarcane management systems (with the application of the insecticide fipronil and the addition of vinasse; with fipronil and no vinasse; and with vinasse and no fipronil, i.e., an organic production system) to evaluate whether the feeding/foraging types vary according to the management system. We tested the hypothesis that organic management increases species diversity because there is no use of chemical inputs. Estimated species richness was significantly higher in the organic management system than in the systems that used fipronil with vinasse. Generalists species were prevalent in all sugarcane fields, regardless of the production system, whereas predatory and fungivorous species were infrequent. However, the organically managed field had many predatory species. Our results suggest that fipronil with vinasse in sugarcane cultivation alters the ant community, possibly disrupting the functions performed by the edaphic fauna, such as control of arthropod crop pests, due to reduced predator species richness.
{"title":"Diversity of ground-dwelling ants in sugarcane plantations under different management systems","authors":"D. R. Souza-Campana, Rogério R. Silva, O. Fernandes, Bianca Sayuri Futikami, O. Bueno, Luan Alberto Odorizzi Santos, M. Morini","doi":"10.1017/s0266467421000481","DOIUrl":"https://doi.org/10.1017/s0266467421000481","url":null,"abstract":"\u0000 In this study, we compared the richness of ground-dwelling ants among three different sugarcane management systems (with the application of the insecticide fipronil and the addition of vinasse; with fipronil and no vinasse; and with vinasse and no fipronil, i.e., an organic production system) to evaluate whether the feeding/foraging types vary according to the management system. We tested the hypothesis that organic management increases species diversity because there is no use of chemical inputs. Estimated species richness was significantly higher in the organic management system than in the systems that used fipronil with vinasse. Generalists species were prevalent in all sugarcane fields, regardless of the production system, whereas predatory and fungivorous species were infrequent. However, the organically managed field had many predatory species. Our results suggest that fipronil with vinasse in sugarcane cultivation alters the ant community, possibly disrupting the functions performed by the edaphic fauna, such as control of arthropod crop pests, due to reduced predator species richness.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46590130","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 : 2022-03-25DOI: 10.1017/s0266467422000049
Tanveer Ahmed, Afifullah Khan
The positive association between landscape compositional heterogeneity and avian species richness is widely accepted, however, birds of different feeding guilds are expected to respond differently because of diverse resource utilisation patterns and ecological tolerance. In the present study, we assessed the response of avian species and avifaunal feeding guilds to landscape compositional heterogeneity and factors associated with their richness. Bird richness and landscape variables, edge density, landscape diversity, and area of land cover types were evaluated at 30 sampling sites in the Terai-Arc landscape of Uttarakhand, India. Univariate regression was performed to investigate the response of birds and various feeding guilds to landscape compositional heterogeneity. Average weighted models of most parsimonious generalised linear regression models (<Δ 2AICc) were developed for various feeding guilds to identify significant predictors of species richness. The richness of overall birds and most feeding guilds, except piscivores and frugivores, responded positively to landscape compositional heterogeneity at variable spatial scales. The scale of effect was largest for carnivore (1.5 km), followed by granivore (1 km), insectivore (0.75 km), and frugi-insectivore, nectarivore, and omnivore (0.5 km). Overall bird species richness was positively associated with landscape diversity, teak plantation, and Sal-mixed forest. The average-weighted models identified edge density and dry riverine forest for frugi-insectivore, barren land and water body for the carnivore, teak plantation, Sal-mixed forest and dry-riverine forest for insectivore, edge density, human habitation/agriculture, teak plantation, barren land and scrubland for granivore, human habitation/agriculture for omnivore and waterbodies for piscivore and frugivore guilds as the significant drivers of species richness. The study concludes that the response to landscape compositional heterogeneity differs among feeding guilds and varies with the spatial scale of analysis. The results of our study are expected to serve as a reference for future studies, exploring the landscape relationship to the avian community in similar environmental conditions.
{"title":"Avifaunal feeding guilds’ response to landscape compositional heterogeneity and their drivers in forest mosaic, Uttarakhand, India","authors":"Tanveer Ahmed, Afifullah Khan","doi":"10.1017/s0266467422000049","DOIUrl":"https://doi.org/10.1017/s0266467422000049","url":null,"abstract":"\u0000 The positive association between landscape compositional heterogeneity and avian species richness is widely accepted, however, birds of different feeding guilds are expected to respond differently because of diverse resource utilisation patterns and ecological tolerance. In the present study, we assessed the response of avian species and avifaunal feeding guilds to landscape compositional heterogeneity and factors associated with their richness. Bird richness and landscape variables, edge density, landscape diversity, and area of land cover types were evaluated at 30 sampling sites in the Terai-Arc landscape of Uttarakhand, India. Univariate regression was performed to investigate the response of birds and various feeding guilds to landscape compositional heterogeneity. Average weighted models of most parsimonious generalised linear regression models (<Δ 2AICc) were developed for various feeding guilds to identify significant predictors of species richness. The richness of overall birds and most feeding guilds, except piscivores and frugivores, responded positively to landscape compositional heterogeneity at variable spatial scales. The scale of effect was largest for carnivore (1.5 km), followed by granivore (1 km), insectivore (0.75 km), and frugi-insectivore, nectarivore, and omnivore (0.5 km). Overall bird species richness was positively associated with landscape diversity, teak plantation, and Sal-mixed forest. The average-weighted models identified edge density and dry riverine forest for frugi-insectivore, barren land and water body for the carnivore, teak plantation, Sal-mixed forest and dry-riverine forest for insectivore, edge density, human habitation/agriculture, teak plantation, barren land and scrubland for granivore, human habitation/agriculture for omnivore and waterbodies for piscivore and frugivore guilds as the significant drivers of species richness. The study concludes that the response to landscape compositional heterogeneity differs among feeding guilds and varies with the spatial scale of analysis. The results of our study are expected to serve as a reference for future studies, exploring the landscape relationship to the avian community in similar environmental conditions.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49547293","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 : 2022-03-25DOI: 10.1017/s0266467422000025
Alamrew Eyayu, A. Getahun
Riverine ecosystems are highly exposed to different forms of human activities and fish distribution in such habitats can be affected by different features of water. Tributaries of the Abbay and Tekeze Basins are supporting all life requesting activities in Ethiopia. Fisheries of these habitats are also the mainstay of livelihoods. However, brutal human activities are affecting these ecosystems and the fish therein. This study was thus undertaken to examine fish distribution and community structure in relation to water parameters in Ayima, Gelegu and Shinfa Rivers. 2719 fish specimens identified into 43 species were sampled using gillnets, cast nets and electro-fishing on a seasonal campaign. Based on frequency of occurrence (%FO), 5 species fell in the category of ‘euconstant occurrence’ or their FO was ≥75%, while many species were laid in the ‘constant occurrence’. Among others, site depth, total phosphorus, dissolved oxygen and river channel diameter were key environmental factors determining fish community structure. Similarity percentage produced an overall average Bray-Curtis dissimilarity of 60.8% between the fish communities of the three rivers. The final model accounted for 77.2% of the total variance in fish composition, and all canonical axes were significant (Monte Carlo test 499, p = 0.002). Generally, this study was conducted in areas where no ecological studies are undertaken and the results obtained from this study could be important for sustainable utilization of Ethiopian fisheries.
{"title":"Distribution and community structure of fish in relation with water physico-chemical parameters of floodplain rivers in the Alitash National Park, Ethiopia","authors":"Alamrew Eyayu, A. Getahun","doi":"10.1017/s0266467422000025","DOIUrl":"https://doi.org/10.1017/s0266467422000025","url":null,"abstract":"\u0000 Riverine ecosystems are highly exposed to different forms of human activities and fish distribution in such habitats can be affected by different features of water. Tributaries of the Abbay and Tekeze Basins are supporting all life requesting activities in Ethiopia. Fisheries of these habitats are also the mainstay of livelihoods. However, brutal human activities are affecting these ecosystems and the fish therein. This study was thus undertaken to examine fish distribution and community structure in relation to water parameters in Ayima, Gelegu and Shinfa Rivers. 2719 fish specimens identified into 43 species were sampled using gillnets, cast nets and electro-fishing on a seasonal campaign. Based on frequency of occurrence (%FO), 5 species fell in the category of ‘euconstant occurrence’ or their FO was ≥75%, while many species were laid in the ‘constant occurrence’. Among others, site depth, total phosphorus, dissolved oxygen and river channel diameter were key environmental factors determining fish community structure. Similarity percentage produced an overall average Bray-Curtis dissimilarity of 60.8% between the fish communities of the three rivers. The final model accounted for 77.2% of the total variance in fish composition, and all canonical axes were significant (Monte Carlo test 499, p = 0.002). Generally, this study was conducted in areas where no ecological studies are undertaken and the results obtained from this study could be important for sustainable utilization of Ethiopian fisheries.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46502103","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 : 2022-03-25DOI: 10.1017/s0266467422000062
Patrícia P. Chaves, S. Timóteo, S. Gomes, A. Rainho
Species-rich ecosystems as tropical forests are extremely vulnerable to anthropogenic destruction. Most tropical plant species rely on animals to disperse their seeds. However, patterns of mutualistic interactions have rarely been explored, and seed dispersal networks are still poorly studied in Africa. Here, we examine how forest edges’ (FE) seed dispersal networks differ from the mature forest (MF) at a West African sub-humid tropical forest within the National Park of Cantanhez (Guinea-Bissau). Additionally, we explore species’ roles within the network. MF had higher fruit availability, more frugivore visitors, and plant–frugivore interactions. Network structure was quite similar between habitats, showing signs of redundancy, and some robustness to species’ extinction. FE was more nested, modular, and specialized, whereas MF had higher connectance, interaction evenness, and robustness to extinction. Most species were generalists, but large-bodied frugivores prevailed at MF. FE showed a higher vulnerability, mostly to the loss of trees. Trees are key, keeping the structure of both networks. Large-bodied frugivores and fruiting-tree species that work as network connectors should thus be the focus of active conservation management in these forests. Only viable populations of these species will ensure a good performance of the seed dispersal network, promoting the natural regeneration of the ecosystem.
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