Pub Date : 2024-09-18DOI: 10.1017/s0266467424000142
Atul A. Joshi, Jayashree Ratnam, Harinandanan Paramjyothi, Mahesh Sankaran
CO2 release rates from soils via soil respiration play an important role in the carbon budget of terrestrial ecosystems. Though the roles of soil temperature and moisture on soil respiration are well recognised, less is known about how their effects vary across different land-cover types. This study looked at the interactive effects of land-cover change and microclimate on temporal patterns of soil respiration in a montane forest-grassland-plantation mosaic in a highly diverse but climatically sensitive ecosystem in the tropical Western Ghats of India. Across all vegetation types, soil respiration rates were highest during south-west monsoon (June–October), when root growth, litter decomposition and microbial activity are relatively high and were lowest during the summer. Among vegetation types, soil respiration rates were higher in grasslands compared to non-native pine plantations, whereas that of forest and invasive wattle (Acacia mearnsii) plantations were intermediate between grasslands and pine plantations. The decline in respiration rates following conversion from grasslands to pine plantations could be due to relatively lower microbial activity, soil temperatures and, subsequently, slower litter decomposition. In addition, the sensitivity of soil respiration to changes in temperature and moisture differed between different vegetation types. Across all vegetation types, respiration was largely insensitive to changes in soil temperature when moisture levels were low. However, when soil moisture levels were high, respiration increased with temperature in grassland and wattle patches, decreased in the case of pine plantations and remained largely unchanged in shola forests. Our results suggest that changes in aboveground vegetation type can significantly affect soil C cycling even in the absence of any underlying differences in soil type.
{"title":"Climate and vegetation collectively drive soil respiration in montane forest-grassland landscapes of the southern Western Ghats, India","authors":"Atul A. Joshi, Jayashree Ratnam, Harinandanan Paramjyothi, Mahesh Sankaran","doi":"10.1017/s0266467424000142","DOIUrl":"https://doi.org/10.1017/s0266467424000142","url":null,"abstract":"CO<jats:sub>2</jats:sub> release rates from soils via soil respiration play an important role in the carbon budget of terrestrial ecosystems. Though the roles of soil temperature and moisture on soil respiration are well recognised, less is known about how their effects vary across different land-cover types. This study looked at the interactive effects of land-cover change and microclimate on temporal patterns of soil respiration in a montane forest-grassland-plantation mosaic in a highly diverse but climatically sensitive ecosystem in the tropical Western Ghats of India. Across all vegetation types, soil respiration rates were highest during south-west monsoon (June–October), when root growth, litter decomposition and microbial activity are relatively high and were lowest during the summer. Among vegetation types, soil respiration rates were higher in grasslands compared to non-native pine plantations, whereas that of forest and invasive wattle (<jats:italic>Acacia mearnsii</jats:italic>) plantations were intermediate between grasslands and pine plantations. The decline in respiration rates following conversion from grasslands to pine plantations could be due to relatively lower microbial activity, soil temperatures and, subsequently, slower litter decomposition. In addition, the sensitivity of soil respiration to changes in temperature and moisture differed between different vegetation types. Across all vegetation types, respiration was largely insensitive to changes in soil temperature when moisture levels were low. However, when soil moisture levels were high, respiration increased with temperature in grassland and wattle patches, decreased in the case of pine plantations and remained largely unchanged in shola forests. Our results suggest that changes in aboveground vegetation type can significantly affect soil C cycling even in the absence of any underlying differences in soil type.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"6 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263301","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 : 2024-05-27DOI: 10.1017/s0266467424000129
Juan Pablo Benavides-Tocarruncho, Horacio Paz, Nelly Rodríguez, Rosa Arrieta, Camila Pizano, Beatriz Salgado-Negret
Fine roots are specialized in nutrient and water acquisition and are critical for species performance and ecosystem functioning. Recent evidence has shown a broad root economic space determined by the orthogonal collaboration and conservation gradients related to resource acquisition and resource conservation, respectively. However, whether these gradients exist among tree species growing in degraded ecosystems where root growth is limited by soil conditions is much an open question. We measured six fine root traits (root diameter, specific root length, root dry matter content, root tissue density, branching intensity, and percentage of arbuscular mycorrhizal colonization) in 11 young tree species growing in sympatry for 9 years in degraded pastures in a tropical dry forest (TDF) in Colombia to determine (1) the covariation between fine root traits and (2) the patterns of belowground niche differentiation among 11 species coexisting under the same soil conditions. The covariation between fine root traits resembled the acquisitive-conservative, but not the collaboration gradient for this degraded habitat. The percentage of mycorrhizal colonization, a critical trait associated with the collaboration gradient, was unrelated to any fine root trait. Furthermore, we found a strong belowground differentiation among species, mainly across root diameter and branching intensity. Our results suggest that compacted degraded soils in TDF landscapes may affect the collaborative association with mycorrhizae, mostly allowing species differentiation along the do-it-yourself gradient. This finding suggests a hypothesis that needs to be tested with more species and sites. We discuss the importance of using root traits to aid species selection for restoration purposes.
{"title":"Belowground differentiation among trees in a degraded tropical dry forest landscape: no evidence of a collaboration gradient","authors":"Juan Pablo Benavides-Tocarruncho, Horacio Paz, Nelly Rodríguez, Rosa Arrieta, Camila Pizano, Beatriz Salgado-Negret","doi":"10.1017/s0266467424000129","DOIUrl":"https://doi.org/10.1017/s0266467424000129","url":null,"abstract":"Fine roots are specialized in nutrient and water acquisition and are critical for species performance and ecosystem functioning. Recent evidence has shown a broad root economic space determined by the orthogonal collaboration and conservation gradients related to resource acquisition and resource conservation, respectively. However, whether these gradients exist among tree species growing in degraded ecosystems where root growth is limited by soil conditions is much an open question. We measured six fine root traits (root diameter, specific root length, root dry matter content, root tissue density, branching intensity, and percentage of arbuscular mycorrhizal colonization) in 11 young tree species growing in sympatry for 9 years in degraded pastures in a tropical dry forest (TDF) in Colombia to determine (1) the covariation between fine root traits and (2) the patterns of belowground niche differentiation among 11 species coexisting under the same soil conditions. The covariation between fine root traits resembled the acquisitive-conservative, but not the collaboration gradient for this degraded habitat. The percentage of mycorrhizal colonization, a critical trait associated with the collaboration gradient, was unrelated to any fine root trait. Furthermore, we found a strong belowground differentiation among species, mainly across root diameter and branching intensity. Our results suggest that compacted degraded soils in TDF landscapes may affect the collaborative association with mycorrhizae, mostly allowing species differentiation along the do-it-yourself gradient. This finding suggests a hypothesis that needs to be tested with more species and sites. We discuss the importance of using root traits to aid species selection for restoration purposes.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"48 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141168409","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 : 2024-05-22DOI: 10.1017/s0266467424000130
Andrés Montes-Rojas, Juan S. Hernández-Rodríguez, Nelson F. Galvis, Andres Link
Tropical drylands are characterized by extreme environmental conditions that, coupled with anthropogenic habitat degradation, can limit the occurrence of native species. Species that are most sensitive to these pressures may be prone to disappear in the context of climate change. In this study, we evaluated the influence of environmental and anthropogenic variables on the occurrence of large mammals and birds at the Tatacoa Desert, an arid region in central Colombia. We tested the relationship between the magnitude of the species’ responses to environmental, human-related variables and to body mass, and percentage of carnivory. Overall, we found a positive association between forest cover and the occupancy of the largest mammals (> 8kg), negative associations between solar radiation and human footprint with individual species occupancy, and a positive association of species occupancy with distance to touristic sites. Our results suggest that the largest and/or more carnivore species may be affected positively by forest cover and negatively by intense solar radiation highlighting the consequences of the increasing process of desertification on large mammals and birds at the upper Magdalena River basin of Colombia under the current scenario of global climate change.
{"title":"Living in the edge: large terrestrial mammal and bird species traits and the ability to cope with extreme environmental conditions and human disturbance in a tropical dry forest in Colombia","authors":"Andrés Montes-Rojas, Juan S. Hernández-Rodríguez, Nelson F. Galvis, Andres Link","doi":"10.1017/s0266467424000130","DOIUrl":"https://doi.org/10.1017/s0266467424000130","url":null,"abstract":"Tropical drylands are characterized by extreme environmental conditions that, coupled with anthropogenic habitat degradation, can limit the occurrence of native species. Species that are most sensitive to these pressures may be prone to disappear in the context of climate change. In this study, we evaluated the influence of environmental and anthropogenic variables on the occurrence of large mammals and birds at the Tatacoa Desert, an arid region in central Colombia. We tested the relationship between the magnitude of the species’ responses to environmental, human-related variables and to body mass, and percentage of carnivory. Overall, we found a positive association between forest cover and the occupancy of the largest mammals (> 8kg), negative associations between solar radiation and human footprint with individual species occupancy, and a positive association of species occupancy with distance to touristic sites. Our results suggest that the largest and/or more carnivore species may be affected positively by forest cover and negatively by intense solar radiation highlighting the consequences of the increasing process of desertification on large mammals and birds at the upper Magdalena River basin of Colombia under the current scenario of global climate change.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"16 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141153343","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 : 2024-04-29DOI: 10.1017/s0266467424000117
Carmen Agglael Vergara-Torres, Susana Valencia-Díaz, José Guadalupe García-Franco, Alejandro Flores-Palacios
The studies about the negative effect of epiphytes on their phorophytes show contradictory results and are based on limited variables (e.g., shoot survival). On branches of Bursera copallifera, we experimented with the transplantation/removal of Tillandsia recurvata and artificial tussocks, measuring shoot survival, growth, generation of new shoots, and production of inflorescences and fruits. Most single traits did not differ between treatments. The generation of new shoots was lower in the treatments where T. recurvata was present and increased in the branches where it was removed. The lowest shoot survival was in the treatments where T. recurvata was present or was removed. Removing T. recurvata increased plant relative fitness, and it was 43% lower in branches with T. recurvata. Tillandsia recurvata is a structural parasite of B. copallifera. A negative effect of epiphytes on their phorophytes appears counterintuitive since it would not be evolutionarily stable for an epiphyte to shorten the lifespan of its support. Tillandsia recurvata populations are concentrated on B. copallifera branches between 2-4 cm in diameter, while smaller branches are mostly empty, so it is possible that the negative effect of T. recurvata occurs in the smallest branches, explaining why T. recurvata populations are biased to larger branches.
关于附生植物对其噬菌体的负面影响的研究结果相互矛盾，而且都是基于有限的变量（如嫩枝存活率）。我们在 Bursera copallifera 的枝条上进行了移植/移除 Tillandsia recurvata 和人工草丛的实验，测量了枝条的存活率、生长、新枝的生成以及花序和果实的产量。大多数单一性状在不同处理之间没有差异。在有 T. recurvata 的处理中，新芽的生成量较低，而在移除 T. recurvata 的枝条中，新芽的生成量则有所增加。在存在或移除 T. recurvata 的处理中，新芽存活率最低。移除 T. recurvata 会增加植物的相对适合度，有 T. recurvata 的枝条相对适合度要低 43%。Tillandsia recurvata 是 B. copallifera 的一种结构寄生植物。附生植物对其噬菌体的负面影响似乎与直觉相反，因为附生植物缩短其支持物的寿命在进化过程中并不稳定。Tillandsia recurvata 的种群主要集中在 B. copallifera 直径 2-4 厘米的枝条上，而较小的枝条上大多没有 Tillandsia recurvata，因此 T. recurvata 的负面影响可能发生在最小的枝条上，这也解释了为什么 T. recurvata 的种群偏向于较大的枝条。
{"title":"Do epiphytes affect the fitness of their phorophytes? The case of Tillandsia recurvata on Bursera copallifera","authors":"Carmen Agglael Vergara-Torres, Susana Valencia-Díaz, José Guadalupe García-Franco, Alejandro Flores-Palacios","doi":"10.1017/s0266467424000117","DOIUrl":"https://doi.org/10.1017/s0266467424000117","url":null,"abstract":"The studies about the negative effect of epiphytes on their phorophytes show contradictory results and are based on limited variables (e.g., shoot survival). On branches of <jats:italic>Bursera copallifera,</jats:italic> we experimented with the transplantation/removal of <jats:italic>Tillandsia recurvata</jats:italic> and artificial tussocks, measuring shoot survival, growth, generation of new shoots, and production of inflorescences and fruits. Most single traits did not differ between treatments. The generation of new shoots was lower in the treatments where <jats:italic>T. recurvata</jats:italic> was present and increased in the branches where it was removed. The lowest shoot survival was in the treatments where <jats:italic>T. recurvata</jats:italic> was present or was removed. Removing <jats:italic>T. recurvata</jats:italic> increased plant relative fitness, and it was 43% lower in branches with <jats:italic>T. recurvata</jats:italic>. <jats:italic>Tillandsia recurvata</jats:italic> is a structural parasite of <jats:italic>B. copallifera</jats:italic>. A negative effect of epiphytes on their phorophytes appears counterintuitive since it would not be evolutionarily stable for an epiphyte to shorten the lifespan of its support. <jats:italic>Tillandsia recurvata</jats:italic> populations are concentrated on <jats:italic>B. copallifera</jats:italic> branches between 2-4 cm in diameter, while smaller branches are mostly empty, so it is possible that the negative effect of <jats:italic>T. recurvata</jats:italic> occurs in the smallest branches, explaining why <jats:italic>T. recurvata</jats:italic> populations are biased to larger branches.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"17 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140831666","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 : 2024-04-17DOI: 10.1017/s0266467424000105
Manuel Mendoza, Eduardo Mendoza, E. Gutiérrez-Peña
The study of species association is of great interest in ecology due to its role in understanding key issues such as patterns of habitat use by animals, species coexistence, biotic interactions, and in general factors affecting community structure and assembly. There are many indices that ecologists commonly use, all based on the observed frequencies of organism occurrences, to evaluate the association between a pair of species. However, few of these indices correspond to proper statistical measures of association, and the inferential aspects of their analysis are often overlooked. In this paper, we propose a Bayesian approach based on a simple multinomial-Dirichlet structure to provide a comprehensive inferential framework for any set of association indices. Our approach provides a full statistical analysis for any association index of interest, free of special requirements on the sample size. We illustrate our procedure with a camera-trapping real-dataset, but the analysis of any other dataset of the same type can be readily produced using the R package basa that accompanies this paper.
物种关联研究在生态学中具有重要意义，因为它有助于理解一些关键问题，如动物对栖息地的利用模式、物种共存、生物相互作用以及影响群落结构和组合的一般因素。生态学家通常使用许多指数来评估一对物种之间的关联，这些指数都基于观察到的生物出现频率。然而，这些指数中很少有与关联的适当统计量相对应的，而且其分析的推论方面往往被忽视。在本文中，我们提出了一种基于简单多叉-Dirichlet 结构的贝叶斯方法，为任何一组关联指数提供全面的推断框架。我们的方法可为任何感兴趣的关联指数提供全面的统计分析，对样本量没有特殊要求。我们用一个摄像头捕捉的真实数据集来说明我们的程序，但使用本文附带的 R 软件包 basa，可以很容易地对任何其他同类数据集进行分析。
{"title":"Statistical analysis of species association indices","authors":"Manuel Mendoza, Eduardo Mendoza, E. Gutiérrez-Peña","doi":"10.1017/s0266467424000105","DOIUrl":"https://doi.org/10.1017/s0266467424000105","url":null,"abstract":"The study of species association is of great interest in ecology due to its role in understanding key issues such as patterns of habitat use by animals, species coexistence, biotic interactions, and in general factors affecting <jats:italic>community structure and assembly</jats:italic>. There are many indices that ecologists commonly use, all based on the observed frequencies of organism occurrences, to evaluate the association between a pair of species. However, few of these indices correspond to proper statistical measures of association, and the inferential aspects of their analysis are often overlooked. In this paper, we propose a Bayesian approach based on a simple multinomial-Dirichlet structure to provide a comprehensive inferential framework for any set of association indices. Our approach provides a full statistical analysis for any association index of interest, free of special requirements on the sample size. We illustrate our procedure with a camera-trapping real-dataset, but the analysis of any other dataset of the same type can be readily produced using the R package <jats:italic>basa</jats:italic> that accompanies this paper.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"2013 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140616484","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 : 2024-04-16DOI: 10.1017/s0266467423000342
Manop Kaewfoo, Sarayudh Bunyavejchewin, Dokrak Marod, Decha Wiwatwittaya, Ian C. Baillie, Stuart J. Davies, Stephen H. Hallett
We characterised the soils and vegetation in 15 sets of four quadrats on and around mounds of Macrotermes annandalei (Isoptera, Macrotermitinae) on a plain of deep dystric clay over limestone in Deciduous Dipterocarp Forest in Northern Thailand. Termites have excavated the mounds from the deep calcareous substrate. The mound soils have darker subsoils, larger contents of clays and exchangeable cations, and higher pH values than the surrounding dystric clay loams. The thickets on the mounds are visually different from the surrounding Deciduous Dipterocarp Forest. They have few dipterocarps and are floristically similar to the regionally important Mixed Deciduous Forest. The clear visual differences are confirmed by floristic similarity, cluster, and canonical correspondence analyses for each of the tree, sapling and seedling size classes. The differences between the mound clays and surrounding red clay loams and the associations between soil and forest types are confirmed by ‘t tests’ and the significant correlations of the soil base status with the main floristic axis of the canonical correspondence analyses. Soil variability due to termites and other agents of pedoturbation can significantly contribute to short-range floristic and structural diversity in some dry tropical forests.
{"title":"Termitaria enhance soil and forest diversity in Deciduous Dipterocarp Forest, Northern Thailand","authors":"Manop Kaewfoo, Sarayudh Bunyavejchewin, Dokrak Marod, Decha Wiwatwittaya, Ian C. Baillie, Stuart J. Davies, Stephen H. Hallett","doi":"10.1017/s0266467423000342","DOIUrl":"https://doi.org/10.1017/s0266467423000342","url":null,"abstract":"We characterised the soils and vegetation in 15 sets of four quadrats on and around mounds of <jats:italic>Macrotermes annandalei</jats:italic> (Isoptera, Macrotermitinae) on a plain of deep dystric clay over limestone in Deciduous Dipterocarp Forest in Northern Thailand. Termites have excavated the mounds from the deep calcareous substrate. The mound soils have darker subsoils, larger contents of clays and exchangeable cations, and higher pH values than the surrounding dystric clay loams. The thickets on the mounds are visually different from the surrounding Deciduous Dipterocarp Forest. They have few dipterocarps and are floristically similar to the regionally important Mixed Deciduous Forest. The clear visual differences are confirmed by floristic similarity, cluster, and canonical correspondence analyses for each of the tree, sapling and seedling size classes. The differences between the mound clays and surrounding red clay loams and the associations between soil and forest types are confirmed by ‘<jats:italic>t</jats:italic> tests’ and the significant correlations of the soil base status with the main floristic axis of the canonical correspondence analyses. Soil variability due to termites and other agents of pedoturbation can significantly contribute to short-range floristic and structural diversity in some dry tropical forests.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"33 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140560581","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 : 2024-04-05DOI: 10.1017/s0266467424000099
Eric Marcon, Ariane Mirabel, Jean-François Molino, Daniel Sabatier
The biodiversity of tropical rainforest is difficult to assess. Yet, its estimation is necessary for conservation purposes, to evaluate our level of knowledge and the risks faced by the forest in relation to global change. Our contribution is to estimate the regional richness of tree species from local but widely spread inventories. We reviewed the methods available, which are nonparametric estimators based on abundance or occurrence data, log-series extrapolation and the universal species–area relationship based on maximum entropy. Appropriate methods depend on the scale considered. Harte’s self-similarity model is suitable at the regional scale, while the log-series extrapolation is not. GuyaDiv is a network of forest plots installed over the whole territory of French Guiana, where trees over 10 cm DBH are identified. We used its information (1315 species censused in 68 one-hectare plots) to estimate the exponent of the species–area relationship, assuming Arrhenius’s power law. We could then extrapolate the number of species from three local, wide inventories (over 2.5 km2). We evaluated the number of tree species around 2200 over the territory.
{"title":"Estimation of the number of tree species in French Guiana by extrapolation of permanent plots richness","authors":"Eric Marcon, Ariane Mirabel, Jean-François Molino, Daniel Sabatier","doi":"10.1017/s0266467424000099","DOIUrl":"https://doi.org/10.1017/s0266467424000099","url":null,"abstract":"The biodiversity of tropical rainforest is difficult to assess. Yet, its estimation is necessary for conservation purposes, to evaluate our level of knowledge and the risks faced by the forest in relation to global change. Our contribution is to estimate the regional richness of tree species from local but widely spread inventories. We reviewed the methods available, which are nonparametric estimators based on abundance or occurrence data, log-series extrapolation and the universal species–area relationship based on maximum entropy. Appropriate methods depend on the scale considered. Harte’s self-similarity model is suitable at the regional scale, while the log-series extrapolation is not. GuyaDiv is a network of forest plots installed over the whole territory of French Guiana, where trees over 10 cm DBH are identified. We used its information (1315 species censused in 68 one-hectare plots) to estimate the exponent of the species–area relationship, assuming Arrhenius’s power law. We could then extrapolate the number of species from three local, wide inventories (over 2.5 km<jats:sup>2</jats:sup>). We evaluated the number of tree species around 2200 over the territory.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"38 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140560579","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 : 2024-04-04DOI: 10.1017/s0266467424000087
Rosario Arreola-Gómez, Eduardo Mendoza
We quantified the amount of pollen carried by bats and birds visiting the flowers of cultivated and wild individuals of the endemic Agave cupreata in western Mexico and estimated the distance to which pollen was moved using diurnal/nocturnal inflorescence exclusions and fluorescent powders. There were no differences in the amount of pollen transported by bats and birds near cultivated and wild agaves, but overall, bats transported greater loads than birds. Nocturnal pollen movement was more frequent, and the maximum distance recorded was 630 m (diurnal and nocturnal), with no transfer between cultivated and wild plants. Bats seem to provide a greater pollination service than birds in our focal anthropized landscape. It is necessary to incorporate management practices into mezcal production that ensure enough food for the wide array of animal species using this resource, which in turn will help to maintain the pollination service.
{"title":"Pollen movement of the endemic Agave cupreata by bats and birds in western Mexico","authors":"Rosario Arreola-Gómez, Eduardo Mendoza","doi":"10.1017/s0266467424000087","DOIUrl":"https://doi.org/10.1017/s0266467424000087","url":null,"abstract":"We quantified the amount of pollen carried by bats and birds visiting the flowers of cultivated and wild individuals of the endemic <jats:italic>Agave cupreata</jats:italic> in western Mexico and estimated the distance to which pollen was moved using diurnal/nocturnal inflorescence exclusions and fluorescent powders. There were no differences in the amount of pollen transported by bats and birds near cultivated and wild agaves, but overall, bats transported greater loads than birds. Nocturnal pollen movement was more frequent, and the maximum distance recorded was 630 m (diurnal and nocturnal), with no transfer between cultivated and wild plants. Bats seem to provide a greater pollination service than birds in our focal anthropized landscape. It is necessary to incorporate management practices into mezcal production that ensure enough food for the wide array of animal species using this resource, which in turn will help to maintain the pollination service.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"108 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140560770","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}
Boswellia papyrifera (Del.) Hochst is a flagship species of semi-arid areas of the East African region with substantial economic, ecological and cultural values. However, its persistence is currently threatened by both anthropogenic and natural pressures. This calls for an immediate conservation action. Planting seedlings of B. papyrifera in natural habitats using nursery-grown seedlings from seed and cuttings has been little successful. Fencing of naturally regenerated seedlings (wildlings) established under the parent trees could be used as an alternative option. The objective of this study was to examine the effect of fencing on the seedling establishment and growth of B. papyrifera wildlings. The experiment was conducted using 36 plots in fenced and open conditions. The results showed that fencing significantly enhances the establishment and growth of B. papyrifera wildlings compared to the open areas. Fenced wildlings exhibited higher survival rates, increased height, greater leaf numbers, larger root collar diameters, larger leaf areas and higher leaf biomass compared to non-fenced wildlings. Therefore, the protection of B. papyrifera seedlings using a fencing intervention can improve the overall establishment and development of B. papyrifera seedlings, thereby contributing to the sustainable conservation and restoration of this valuable species.
{"title":"Fencing improves the establishment and growth of Boswellia papyrifera (Del.) Hochst wildlings","authors":"Emiru Birhane, Abadi Tesfay, Abebe Damtew, Zenebe Girmay, Tesfay Gidey, Frans Bongers","doi":"10.1017/s0266467424000075","DOIUrl":"https://doi.org/10.1017/s0266467424000075","url":null,"abstract":"<jats:italic>Boswellia papyrifera</jats:italic> (Del.) Hochst is a flagship species of semi-arid areas of the East African region with substantial economic, ecological and cultural values. However, its persistence is currently threatened by both anthropogenic and natural pressures. This calls for an immediate conservation action. Planting seedlings of <jats:italic>B. papyrifera</jats:italic> in natural habitats using nursery-grown seedlings from seed and cuttings has been little successful. Fencing of naturally regenerated seedlings (wildlings) established under the parent trees could be used as an alternative option. The objective of this study was to examine the effect of fencing on the seedling establishment and growth of <jats:italic>B. papyrifera</jats:italic> wildlings. The experiment was conducted using 36 plots in fenced and open conditions. The results showed that fencing significantly enhances the establishment and growth of <jats:italic>B. papyrifera</jats:italic> wildlings compared to the open areas. Fenced wildlings exhibited higher survival rates, increased height, greater leaf numbers, larger root collar diameters, larger leaf areas and higher leaf biomass compared to non-fenced wildlings. Therefore, the protection of <jats:italic>B. papyrifera</jats:italic> seedlings using a fencing intervention can improve the overall establishment and development of <jats:italic>B. papyrifera</jats:italic> seedlings, thereby contributing to the sustainable conservation and restoration of this valuable species.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"87 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140302251","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 : 2024-03-21DOI: 10.1017/s0266467424000051
Tom Ball, Edmund Tanner
Mature leaves of tree seedlings were exposed to high light in four experimental gaps in the Jamaican upper montane rainforest (UMRF). Two of the six species studied were light-demanders: Alchornea latifolia and Clethra occidentalis. Two were gap-favoured: Pittosporum undulatum (an invasive) and Palicourea alpina (a subcanopy shrub). One was intermediate: Hedyosmum arborescens, and one was shade-tolerant: Guarea glabra. After five months, the following significant changes occurred in shade leaves that were exposed to gaps (‘shade-to-gap’ leaves; values as % of those in the pre-gap shade): maximum rate of photosynthesis + 40% (Alchornea), +35% (Clethra), −34% (Pittosporum), +72% (Palicourea); dark respiration +120% (Alchornea), +140% (Clethra), +60% (Pittosporum), +233% (Palicourea), +175% (Hedyosmum), +100% (Guarea); leaf thickness +18% (Alchornea), +18% (Clethra), +14% (Palicourea); leaf mass per unit area +18% (Alchornea), +15% (Pittosporum). Leaves produced in the gaps were (as a percentage of total live leaf number) 74% (Alchornea), 71% (Clethra), 50% (Pittosporum), 71% (Palicourea), 62% (Hedyosmum) and 50% (Guarea). Photosynthetic rates of leaves produced in the gaps were 53–120% higher than ‘shade-to-gap’ leaves. Overall, shade leaves on the three native, more light-demanding species (Alchornea, Clethra and Palicourea) showed photosynthetic acclimation, while the more shade-tolerant species (Hedyosmum and Guarea and Pittosporum undulatum) showed little acclimation in shade-to-gap leaves.
{"title":"Photosynthetic acclimation, leaf turnover and growth in tree seedlings suddenly exposed to gaps in Jamaican montane rainforest","authors":"Tom Ball, Edmund Tanner","doi":"10.1017/s0266467424000051","DOIUrl":"https://doi.org/10.1017/s0266467424000051","url":null,"abstract":"Mature leaves of tree seedlings were exposed to high light in four experimental gaps in the Jamaican upper montane rainforest (UMRF). Two of the six species studied were light-demanders: <jats:italic>Alchornea latifolia</jats:italic> and <jats:italic>Clethra occidentalis</jats:italic>. Two were gap-favoured: <jats:italic>Pittosporum undulatum</jats:italic> (an invasive) and <jats:italic>Palicourea alpina</jats:italic> (a subcanopy shrub). One was intermediate: <jats:italic>Hedyosmum arborescens</jats:italic>, and one was shade-tolerant: <jats:italic>Guarea glabra</jats:italic>. After five months, the following significant changes occurred in shade leaves that were exposed to gaps (‘shade-to-gap’ leaves; values as % of those in the pre-gap shade): maximum rate of photosynthesis + 40% (<jats:italic>Alchornea</jats:italic>), +35% (<jats:italic>Clethra</jats:italic>), −34% (<jats:italic>Pittosporum</jats:italic>), +72% (<jats:italic>Palicourea</jats:italic>); dark respiration +120% (<jats:italic>Alchornea</jats:italic>), +140% (<jats:italic>Clethra</jats:italic>), +60% (<jats:italic>Pittosporum</jats:italic>), +233% (<jats:italic>Palicourea</jats:italic>), +175% (<jats:italic>Hedyosmum</jats:italic>), +100% (<jats:italic>Guarea</jats:italic>); leaf thickness +18% (<jats:italic>Alchornea</jats:italic>), +18% (<jats:italic>Clethra</jats:italic>), +14% (<jats:italic>Palicourea</jats:italic>); leaf mass per unit area +18% (<jats:italic>Alchornea</jats:italic>), +15% (<jats:italic>Pittosporum</jats:italic>). Leaves produced in the gaps were (as a percentage of total live leaf number) 74% (<jats:italic>Alchornea</jats:italic>), 71% (Clethra), 50% (<jats:italic>Pittosporum</jats:italic>), 71% (<jats:italic>Palicourea</jats:italic>), 62% (<jats:italic>Hedyosmum</jats:italic>) and 50% (<jats:italic>Guarea</jats:italic>). Photosynthetic rates of leaves produced in the gaps were 53–120% higher than ‘shade-to-gap’ leaves. Overall, shade leaves on the three native, more light-demanding species (<jats:italic>Alchornea</jats:italic>, <jats:italic>Clethra</jats:italic> and <jats:italic>Palicourea</jats:italic>) showed photosynthetic acclimation, while the more shade-tolerant species (<jats:italic>Hedyosmum</jats:italic> and <jats:italic>Guarea</jats:italic> and <jats:italic>Pittosporum undulatum</jats:italic>) showed little acclimation in shade-to-gap leaves.","PeriodicalId":49968,"journal":{"name":"Journal of Tropical Ecology","volume":"24 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140205573","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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