Abstract. Ecosystem functions such as seed production are the result of a complex interplay between competitive plant–plant interactions and mutualistic pollinator–plant interactions. In this interplay, spatial plant aggregation could work in two different directions: it could increase hetero- and conspecific competition, thus reducing seed production; but it could also attract pollinators, increasing plant fitness. To shed light on how plant spatial arrangement modulates this balance, we conducted a field study in a Mediterranean annual grassland with three focal plant species with different phenology, Chamaemelum fuscatum (early phenology), Leontodon maroccanus (middle phenology) and Pulicaria paludosa (late phenology), and a diverse guild of pollinators (flies, bees, beetles and butterflies). All three species showed spatial aggregation of conspecific individuals. Additionally, we found that the two mechanisms were working simultaneously: crowded neighborhoods reduced individual seed production via plant–plant competition, but they also made individual plants more attractive for some pollinator guilds, increasing visitation rates and plant fitness. The balance between these two forces varied depending on the focal species and the spatial scale considered. Therefore, our results indicate that mutualistic interactions do not always effectively compensate for competitive interactions in situations of spatial aggregation of flowering plants, at least in our study system. We highlight the importance of explicitly considering the spatial structure at different spatial scales of multitrophic interactions to better understand individual plant fitness and community dynamics.
{"title":"Plant spatial aggregation modulates the interplay between plant competition and pollinator attraction with contrasting outcomes of plant fitness","authors":"María Hurtado, Oscar Godoy, Ignasi Bartomeus","doi":"10.5194/we-23-51-2023","DOIUrl":"https://doi.org/10.5194/we-23-51-2023","url":null,"abstract":"Abstract. Ecosystem functions such as seed production are the result of a complex interplay between competitive plant–plant interactions and mutualistic pollinator–plant interactions. In this interplay, spatial plant aggregation could work in two different directions: it could increase hetero- and conspecific competition, thus reducing seed production; but it could also attract pollinators, increasing plant fitness. To shed light on how plant spatial arrangement modulates this balance, we conducted a field study in a Mediterranean annual grassland with three focal plant species with different phenology, Chamaemelum fuscatum (early phenology), Leontodon maroccanus (middle phenology) and Pulicaria paludosa (late phenology), and a diverse guild of pollinators (flies, bees, beetles and butterflies). All three species showed spatial aggregation of conspecific individuals. Additionally, we found that the two mechanisms were working simultaneously: crowded neighborhoods reduced individual seed production via plant–plant competition, but they also made individual plants more attractive for some pollinator guilds, increasing visitation rates and plant fitness. The balance between these two forces varied depending on the focal species and the spatial scale considered. Therefore, our results indicate that mutualistic interactions do not always effectively compensate for competitive interactions in situations of spatial aggregation of flowering plants, at least in our study system. We highlight the importance of explicitly considering the spatial structure at different spatial scales of multitrophic interactions to better understand individual plant fitness and community dynamics.","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"43 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135468566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Katja Wehner, Matthias Brandt, A. Hilpert, Nadja K. Simons, N. Blüthgen
Abstract. Declines in species richness and abundance of insects over the last decades are often driven by anthropogenic land use and can have severe consequences for ecosystem functioning. Many studies investigated the effects of land-use intensification on the distribution of phenotypic traits across species at the community level, often with mixed results. However, biotic and abiotic environmental filters and potential selection act on individuals within each species, i.e., at the species' population level, and thus drive the extent of intraspecific phenotypic variation. Here, we compare the morphological trait variation within selected species of dung beetles, bees and grasshoppers and link this variation to land-use intensity in forests and grasslands. Selected traits included absolute body size measures and relative leg, wing or eye size, or shape and are often interpreted as “functional traits” in the context of specific ecological responses or effects. We predicted that trait variability among individuals of arthropod species is reduced in intensively used ecosystems (with pronounced environmental filtering) compared to low-intensity ones, particularly for arthropod species that were more abundant in intensively used sites (“land-use winners” compared to “losers”). In general, only few effects of land-use intensity on trait variation were found showing a decreasing variation with increasing land-use intensity in forests but an increasing variation in grasslands. Although many studies confirmed strong land-use impacts on species composition, diversity and trait distribution, including evidence from the same land-use gradients, we were not able to confirm consistent effects at the intraspecific level. However, the choice of which traits are included in analyses and the linkage between phenotypic variation and genetic variability can strongly influence the conclusions drawn on ecological processes. Therefore, we suggest extending the use of intraspecific trait variation on other, more specific response or effect traits and a broader range of species in future studies.
{"title":"Little evidence for land-use filters on intraspecific trait variation in three arthropod groups","authors":"Katja Wehner, Matthias Brandt, A. Hilpert, Nadja K. Simons, N. Blüthgen","doi":"10.5194/we-23-35-2023","DOIUrl":"https://doi.org/10.5194/we-23-35-2023","url":null,"abstract":"Abstract. Declines in species richness and abundance of insects over the last decades\u0000are often driven by anthropogenic land use and can have severe consequences\u0000for ecosystem functioning. Many studies investigated the effects of land-use intensification on the distribution of phenotypic traits across species at the community level, often with mixed results. However, biotic and abiotic environmental filters and potential selection act on individuals within each species, i.e., at the species' population level, and thus drive the extent of intraspecific phenotypic variation. Here, we compare the morphological trait variation within selected species of dung beetles, bees and grasshoppers and link this variation to land-use intensity in forests and grasslands. Selected traits included absolute body size measures and relative leg, wing or eye size, or shape and are often interpreted as “functional traits” in the context of specific ecological responses or effects. We predicted that trait variability among individuals of arthropod species is reduced in intensively\u0000used ecosystems (with pronounced environmental filtering) compared to\u0000low-intensity ones, particularly for arthropod species that were more\u0000abundant in intensively used sites (“land-use winners” compared to\u0000“losers”). In general, only few effects of land-use intensity on trait\u0000variation were found showing a decreasing variation with increasing land-use\u0000intensity in forests but an increasing variation in grasslands. Although\u0000many studies confirmed strong land-use impacts on species composition,\u0000diversity and trait distribution, including evidence from the same land-use\u0000gradients, we were not able to confirm consistent effects at the\u0000intraspecific level. However, the choice of which traits are included in\u0000analyses and the linkage between phenotypic variation and genetic\u0000variability can strongly influence the conclusions drawn on ecological\u0000processes. Therefore, we suggest extending the use of intraspecific trait\u0000variation on other, more specific response or effect traits and a broader\u0000range of species in future studies.\u0000","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"59 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84899211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Anindita Bidisha Chatterjee, K. Sankar, Y. Jhala, Q. Qureshi
Abstract. The global decline of large carnivore populations warrants scientific insights into intraguild relationships. Patterns of co-occurrence among sympatric predators are governed by their density, distribution, diet, activity overlaps, and behavioural strategies. Tigers are sympatric with leopards across their distribution range, overlap substantially in their diet, and are both nocturnal. The subdominant leopard is believed to coexist with tigers via several mechanisms like spatial segregation, temporal avoidance, and differential prey selection. Investigation of spatio-temporal patterns of co-occurrence of tigers and leopards can provide insights on mechanisms that permit coexistence. We used camera trap-based photo captures of tigers and leopards in prey-rich (58.15±10.61 ungulates per km2) Pench Tiger Reserve to determine their spatio-temporal patterns of co-occurrence. Spatially explicit density estimates of tigers were approximately 5 per 100 km2 and leopards were approximately 4.5 per 100 km2 and remained stable over the years. This implies that both these co-predators are likely to attain carrying capacity within the study area. Areas with high tiger density had lower leopard density. Quantile regression analysis between tiger and leopard density at 2×2 km grid showed that leopard density had a parabolic relationship with tiger density, initially increasing with tigers (β=0.393; p=0.001), stable at medium tiger density (β=0.13 and p=0.15), and declining at high tiger densities (β=-0.37 and p<0.001). Both tigers and leopards were crepuscular in nature with no temporal segregation (Δ=89 %). Time lag of consecutive leopard photograph after a tiger capture ranged between 0.002 to 36.29 d. Leopard use of trails was not related to use by tigers. Our results suggest that leopards adjust their usage of space at fine scales to avoid confrontations with tigers. We also observed high temporal overlap and no spatio-temporal segregation between tigers and leopards, despite the two predators being nocturnal and having similar prey choices. The availability of ample prey within the study area is likely to be the driving factor of the co-occurrence of tigers and leopards within this dry deciduous habitat of central India.
摘要大型食肉动物种群的全球减少，使我们有理由对野生动物之间的关系有科学的认识。同域食肉动物共生的模式受其密度、分布、饮食、活动重叠和行为策略的支配。老虎与豹子在它们的分布范围内是同乡的，它们的饮食有很大的重叠，而且都是夜行动物。亚优势豹被认为是通过空间隔离、时间回避和不同猎物选择等机制与老虎共存的。对虎豹共存的时空格局进行研究，有助于揭示虎豹共存的机制。利用相机捕捉法，对丰富猎物(58.15±10.61有蹄动物/ km2)的潘奇老虎保护区的虎、豹共现的时空格局进行了研究。老虎的空间密度估计约为每100平方公里5只，豹的空间密度估计约为每100平方公里4.5只，多年来保持稳定。这意味着这两种生态捕食者都可能在研究区域内达到承载能力。虎密度高的地区，豹密度较低。2×2 km网格虎、豹密度的分位数回归分析表明，豹密度与虎密度呈抛物线关系，初始值随虎增加而增加(β=0.393;P =0.001)，中等老虎密度时稳定(β=0.13, P =0.15)，高老虎密度时下降(β=-0.37, P <0.001)。老虎和豹子在自然界中都是匍匐的，没有时间隔离(Δ= 89%)。捕获老虎后连续拍摄豹子照片的时间滞后在0.002 ~ 36.29 d之间。豹子对小径的利用与老虎的利用无关。研究结果表明，豹子通过调整空间尺度来避免与老虎发生冲突。我们还观察到，尽管老虎和豹子都是夜行动物，并且有相似的猎物选择，但老虎和豹子之间的时间重叠程度很高，没有时空隔离。研究区域内充足的猎物可能是印度中部这个干燥的落叶栖息地中老虎和豹子共存的驱动因素。
{"title":"Spatio-temporal patterns of co-occurrence of tigers and leopards within a protected area in central India","authors":"Anindita Bidisha Chatterjee, K. Sankar, Y. Jhala, Q. Qureshi","doi":"10.5194/we-23-17-2023","DOIUrl":"https://doi.org/10.5194/we-23-17-2023","url":null,"abstract":"Abstract. The global decline of large carnivore populations warrants scientific\u0000insights into intraguild relationships. Patterns of co-occurrence among\u0000sympatric predators are governed by their density, distribution, diet,\u0000activity overlaps, and behavioural strategies. Tigers are sympatric with\u0000leopards across their distribution range, overlap substantially in their\u0000diet, and are both nocturnal. The subdominant leopard is believed to coexist\u0000with tigers via several mechanisms like spatial segregation, temporal\u0000avoidance, and differential prey selection. Investigation of\u0000spatio-temporal patterns of co-occurrence of tigers and leopards can provide\u0000insights on mechanisms that permit coexistence. We used camera trap-based\u0000photo captures of tigers and leopards in prey-rich (58.15±10.61\u0000ungulates per km2) Pench Tiger Reserve to determine their spatio-temporal\u0000patterns of co-occurrence. Spatially explicit density estimates of tigers\u0000were approximately 5 per 100 km2 and leopards were approximately 4.5 per\u0000100 km2 and remained stable over the years. This implies that both these\u0000co-predators are likely to attain carrying capacity within the study area.\u0000Areas with high tiger density had lower leopard density. Quantile regression\u0000analysis between tiger and leopard density at 2×2 km grid showed that\u0000leopard density had a parabolic relationship with tiger density, initially\u0000increasing with tigers (β=0.393; p=0.001), stable at medium tiger\u0000density (β=0.13 and p=0.15), and declining at high tiger densities\u0000(β=-0.37 and p<0.001). Both tigers and leopards were\u0000crepuscular in nature with no temporal segregation (Δ=89 %).\u0000Time lag of consecutive leopard photograph after a tiger capture ranged\u0000between 0.002 to 36.29 d. Leopard use of trails was not related to use by tigers. Our results suggest that leopards adjust their usage of space\u0000at fine scales to avoid confrontations with tigers. We also observed high\u0000temporal overlap and no spatio-temporal segregation between tigers and\u0000leopards, despite the two predators being nocturnal and having similar prey\u0000choices. The availability of ample prey within the study area is likely to\u0000be the driving factor of the co-occurrence of tigers and leopards within\u0000this dry deciduous habitat of central India.\u0000","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"C-21 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85083079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Peihua Zhang, D. Bonte, G. D. De Deyn, M. Vandegehuchte
Abstract. The spatial distribution of resources affects ecological processes at all levels of biological organization. However, it remains to be tested how the spatial configuration of belowground resources affects the community dynamics of soil organisms and resulting plant–soil feedbacks. We used Agrostis stolonifera plants in different spatial configurations in mesocosms to study the dispersal patterns of soil nematodes and rotifers. Plant–soil feedbacks were later assessed by re-sowing the mesocosms with Lolium perenne and Plantago lanceolata after removing all the initial A. stolonifera plants from the mesocosms. Bacterial-feeding nematodes and rotifers spread fast, whereas plant-feeding nematodes barely dispersed from the release sites. These spread patterns of nematodes and rotifers depended on the life-history traits and not on the spatial pattern of the plants. However, more clustered plants developed a higher total biomass and caused a reduced growth of the subsequent vegetation. Our results demonstrate that the mere spatial pattern of a single plant species can alter the strength of plant–soil feedbacks. This has important implications for understanding the impact of planting or replanting schemes and other changes in the spatial configuration of plants on long-term vegetation development and succession.
{"title":"Plant clustering generates negative plant–soil feedback without changing the spatial distribution of soil fauna","authors":"Peihua Zhang, D. Bonte, G. D. De Deyn, M. Vandegehuchte","doi":"10.5194/we-23-1-2023","DOIUrl":"https://doi.org/10.5194/we-23-1-2023","url":null,"abstract":"Abstract. The spatial distribution of resources affects ecological processes at all\u0000levels of biological organization. However, it remains to be tested how the\u0000spatial configuration of belowground resources affects the community\u0000dynamics of soil organisms and resulting plant–soil feedbacks. We used Agrostis stolonifera plants in different spatial configurations in\u0000mesocosms to study the dispersal patterns of soil nematodes and rotifers.\u0000Plant–soil feedbacks were later assessed by re-sowing the mesocosms with\u0000Lolium perenne and Plantago lanceolata after removing all the initial A. stolonifera plants from the mesocosms. Bacterial-feeding nematodes and\u0000rotifers spread fast, whereas plant-feeding nematodes barely dispersed from\u0000the release sites. These spread patterns of nematodes and rotifers depended\u0000on the life-history traits and not on the spatial pattern of the plants.\u0000However, more clustered plants developed a higher total biomass and caused a reduced growth of the subsequent vegetation. Our results demonstrate that the mere spatial pattern of a single plant\u0000species can alter the strength of plant–soil feedbacks. This has important\u0000implications for understanding the impact of planting or replanting schemes\u0000and other changes in the spatial configuration of plants on long-term\u0000vegetation development and succession.\u0000","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"10 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89680212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Robert J. G. Cockroft, W. Richard Jenkins, Anthony G. Irwin, Steve Norman, Kevin C. Brown
Phantom midges, Chaoborus spp. (Diptera: Chaoboridae), are an important taxon in environmental risk assessment of plant protection products due to the sensitivity of their larvae to insecticides. To aid modelling of population responses to xenobiotic exposure, information on emergence timing and voltinism is needed, but definitive evidence to support these parameters is lacking in the literature. We investigated emergence timing of overwintering Chaoborus larvae and the number of life cycles occurring per year in two separate, mesh-enclosed outdoor microcosm experiments in the spring and summer of 2017.Emergence from overwintering larvae of a population of predominantly C. obscuripes (99.68 %) commenced on 13 April and peaked on 2 May. The majority of emergence was completed by 3 June. Emergence success ranged from 51.4 % to 66.2 %, indicating that for overwintered C. obscuripes larvae, adults emerged contemporaneously in spring, rather than sporadically over the course of spring and summer.A population of C. crystallinus larvae produced up to four discrete generations over the spring and summer months (i.e. were confirmed to be multivoltine), with life cycle durations (egg-to-egg) ranging from 14 to 56 d. The differences in life cycle strategy observed in this study have implications for assessment of the capacity of populations of Chaoborus spp. to recover if there are localised impacts due to insecticide exposure or other stressors.
{"title":"Emergence timing and voltinism of phantom midges, Chaoborus spp., in the UK","authors":"Robert J. G. Cockroft, W. Richard Jenkins, Anthony G. Irwin, Steve Norman, Kevin C. Brown","doi":"10.5194/we-22-101-2022","DOIUrl":"https://doi.org/10.5194/we-22-101-2022","url":null,"abstract":"Phantom midges, <i>Chaoborus</i> spp. (Diptera: Chaoboridae), are an\u0000important taxon in environmental risk assessment of plant protection products due to the sensitivity of their larvae to insecticides. To aid\u0000modelling of population responses to xenobiotic exposure, information on\u0000emergence timing and voltinism is needed, but definitive evidence to support\u0000these parameters is lacking in the literature. We investigated emergence\u0000timing of overwintering <i>Chaoborus</i> larvae and the number of life cycles occurring per year in two separate, mesh-enclosed outdoor microcosm experiments in the spring and summer of 2017.Emergence from overwintering larvae of a population of predominantly <i>C. obscuripes</i> (99.68 %) commenced on 13 April and peaked on 2 May. The majority of emergence was completed by 3 June. Emergence success ranged from 51.4 % to 66.2 %, indicating that for overwintered <i>C. obscuripes</i> larvae, adults emerged contemporaneously in spring, rather than sporadically over the course of spring and summer.A population of <i>C. crystallinus</i> larvae produced up to four discrete generations over the spring and summer months (i.e. were confirmed to be multivoltine), with life cycle durations (egg-to-egg) ranging from 14 to 56 d. The differences in life cycle strategy observed in this study have implications for assessment of the capacity of populations of <i>Chaoborus</i> spp. to recover if there are localised impacts due to insecticide exposure or other stressors.","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"31 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138541934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Abstract. A recent publication in Ecosphere claimed to report the first case of a predation event by a theridiid spider on a bat globally and the first case of a member of the genus Steatoda preying on a mammal globally, and the paper concludes with possible implications for public health. Predation is typically understood to mean “capture, kill, and eat”. However, none of these aspects had been observed. Moreover, key aspects of bat biology were not taken into account, including that the bat in question was a flightless newborn, the capture of which would require some explanation. We revisit this interesting observation considering both bat and spider ecology.
{"title":"Comment on Dunbar et al. (2022) “Webslinger vs. Dark Knight: First record of a false widow spider Steatoda nobilis preying on a pipistrelle bat in Britain”","authors":"S. Dool, G. Uhl","doi":"10.5194/we-22-97-2022","DOIUrl":"https://doi.org/10.5194/we-22-97-2022","url":null,"abstract":"Abstract. A recent publication in Ecosphere claimed to report the first case of a predation event by a theridiid spider on a bat globally and the first case of a member of the genus Steatoda preying on a mammal globally, and the paper concludes with possible implications for public health. Predation is typically understood to mean “capture, kill, and eat”. However, none of these aspects had been observed. Moreover, key aspects of bat biology were not taken into account, including that the bat in question was a flightless newborn, the capture of which would require some explanation. We revisit this interesting observation considering both bat and spider ecology.\u0000","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"11 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84250006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Fernando T. Maestre, David J. Eldridge, Nicolas Gross, Yoann Le Bagousse-Pinguet, Hugo Saiz, Beatriz Gozalo, Victoria Ochoa, Juan J. Gaitán
Grazing by domestic livestock is both the main land use across drylands worldwide and a major desertification and global change driver. The ecological consequences of this key human activity have been studied for decades, and there is a wealth of information on its impacts on biodiversity and ecosystem processes. However, most field assessments of the ecological impacts of grazing on drylands conducted to date have been carried out at local or regional scales and have focused on single ecosystem attributes (e.g., plant productivity) or particular taxa (mainly aboveground, e.g., plants). Here we introduce the BIODESERT survey, the first systematic field survey devoted to evaluating the joint impacts of grazing by domestic livestock and climate on the structure and functioning of dryland ecosystems worldwide. This collaborative global survey was carried out between 2016 and 2019 and has involved the collection of field data and plant, biocrust, and soil samples from a total of 326 45 m × 45 m plots from 98 sites located in 25 countries from 6 continents. Here we describe the major characteristics and the field protocols used in this survey. We also introduce the organizational aspects followed, as these can be helpful to everyone wishing to establish a global collaborative network of researchers. The BIODESERT survey provides baseline data to assess the current status of dryland rangelands worldwide and the impacts of grazing on these key ecosystems, and it constitutes a good example of the power of collaborative research networks to study the ecology of our planet using much-needed field data.
{"title":"The BIODESERT survey: assessing the impacts of grazing on the structure and functioning of global drylands","authors":"Fernando T. Maestre, David J. Eldridge, Nicolas Gross, Yoann Le Bagousse-Pinguet, Hugo Saiz, Beatriz Gozalo, Victoria Ochoa, Juan J. Gaitán","doi":"10.5194/we-22-75-2022","DOIUrl":"https://doi.org/10.5194/we-22-75-2022","url":null,"abstract":"Grazing by domestic livestock is both the main land use across\u0000drylands worldwide and a major desertification and global change driver. The\u0000ecological consequences of this key human activity have been studied for\u0000decades, and there is a wealth of information on its impacts on biodiversity\u0000and ecosystem processes. However, most field assessments of the ecological\u0000impacts of grazing on drylands conducted to date have been carried out at\u0000local or regional scales and have focused on single ecosystem attributes\u0000(e.g., plant productivity) or particular taxa (mainly aboveground, e.g.,\u0000plants). Here we introduce the BIODESERT survey, the first systematic field\u0000survey devoted to evaluating the joint impacts of grazing by domestic\u0000livestock and climate on the structure and functioning of dryland ecosystems\u0000worldwide. This collaborative global survey was carried out between 2016 and\u00002019 and has involved the collection of field data and plant, biocrust, and soil\u0000samples from a total of 326 45 m <span>×</span> 45 m plots from 98 sites located in 25\u0000countries from 6 continents. Here we describe the major characteristics\u0000and the field protocols used in this survey. We also introduce the\u0000organizational aspects followed, as these can be helpful to everyone wishing\u0000to establish a global collaborative network of researchers. The BIODESERT\u0000survey provides baseline data to assess the current status of dryland\u0000rangelands worldwide and the impacts of grazing on these key ecosystems, and it\u0000constitutes a good example of the power of collaborative research networks\u0000to study the ecology of our planet using much-needed field data.","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"4 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138536478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Thales Castilhos de Freitas, Gustavo Crizel Gomes, Artur Ramos Molina, Ernestino de Souza Gomes Guarino, Cristiano Agra Iserhard, R. Beltrame
Abstract. One of the main barriers to restoration is the arrival of diaspores in degraded areas. However, this process can be hampered in open areas without trees in the landscape. For that, artificial perches are used to attract and provide a landing area for avian seed dispersers, to enhance seed rain. Our objective was to evaluate the effect of the distance of artificial perches in relation to a forest fragment on the diversity and composition of seed rain in an agricultural fallow area, including alien invasive plant species. We also aimed to record and characterize the bird species that potentially act as seed dispersers. Thus, we used artificial perches at three different distances from a forest fragment (5, 25, and 50 m). Four seed traps were arranged under the perches at each distance, and four control seed traps were interspersed with these and distanced at 7.5 m. Furthermore, we placed four seed traps inside the forest fragment at 5 m from the edge. We also carried out 80 h of focal observation of the avifauna that used artificial perches. A total of 24 655 seeds were sampled across all treatments. There was a significant difference in seed abundance and richness between artificial perches, control seed traps, and forest seed traps. Seed deposition increased with distance from the forest fragment (50, 25, and 5 m). An ordination procedure indicated the formation of three plant seed communities, with the forest community being most distinct. The invasive exotic species Pittosporum undulatum (Australian cheesewood) was the third most abundant in the seed rain. We observed 24 bird species from 12 families using artificial perches. The Tyrannidae family was the most represented. We showed that artificial perches are efficient structures for attracting birds, increasing the richness and abundance of seed species. Artificial perches at 25 and 50 m were more efficient possibly due to the provision of greater visibility for birds. Therefore, artificial perches are efficient in increasing seed rain in the fallow area but should be used with caution in landscapes with the presence of alien species. These findings contribute to increasing knowledge about overcoming the first barrier to ecological restoration, which is the arrival of diaspores in degraded areas, and showing the importance of birds in this process.
{"title":"Artificial perches increase bird-mediated seed rain in agricultural fallow area in southern Brazil","authors":"Thales Castilhos de Freitas, Gustavo Crizel Gomes, Artur Ramos Molina, Ernestino de Souza Gomes Guarino, Cristiano Agra Iserhard, R. Beltrame","doi":"10.5194/we-22-59-2022","DOIUrl":"https://doi.org/10.5194/we-22-59-2022","url":null,"abstract":"Abstract. One of the main barriers to restoration is the arrival of diaspores in degraded areas. However, this process can be hampered in open areas without\u0000trees in the landscape. For that, artificial perches are used to attract and provide a landing area for avian seed dispersers, to enhance seed\u0000rain. Our objective was to evaluate the effect of the distance of artificial perches in relation to a forest fragment on the diversity and\u0000composition of seed rain in an agricultural fallow area, including alien invasive plant species. We also aimed to record and characterize the bird\u0000species that potentially act as seed dispersers. Thus, we used artificial perches at three different distances from a forest fragment (5, 25, and\u000050 m). Four seed traps were arranged under the perches at each distance, and four control seed traps were interspersed with these and distanced at 7.5 m. Furthermore, we placed four seed traps inside the forest fragment at 5 m from the edge. We also carried out 80 h of focal observation of the avifauna that used artificial perches. A total of 24 655 seeds were sampled across all treatments. There was a significant difference in seed abundance and richness between artificial perches, control seed traps, and forest seed traps. Seed deposition increased with distance from the forest fragment (50, 25, and 5 m). An ordination procedure indicated the formation of three plant seed communities, with the forest community being most distinct. The invasive exotic species Pittosporum undulatum (Australian cheesewood) was the third most abundant in the seed rain. We observed 24 bird species from 12 families using artificial perches. The Tyrannidae family was the most represented. We showed that artificial perches are efficient structures for attracting birds, increasing the richness and abundance of seed species. Artificial perches at 25 and 50 m were more efficient possibly due to the provision of greater visibility for birds. Therefore, artificial perches are efficient in increasing seed rain in the fallow area but should be used with caution in landscapes with the presence of alien species. These findings contribute to increasing knowledge about overcoming the first barrier to ecological restoration, which is the arrival of diaspores in degraded areas, and\u0000showing the importance of birds in this process.\u0000","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"21 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87435058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Abstract. On the eastern Tibetan Plateau, the growth of trees is strongly affected by climate change. Previous researchers have found that climate warming changes thermal and hydraulic conditions, lengthening the growing season and promoting tree growth. Some studies have analyzed the effects of drought, precipitation, and temperature on tree growth. However, previous studies have mainly focused on natural forests, with few studies on the response of plantations to climate change. Therefore, we studied the relationship between dendrochronology (basal area increment, BAI), normalized difference vegetation index (NDVI), and climate factors to explore the response of Picea likiangensis var. rubescens plantations to climate change. The results showed that from 1990 to 2018, the temperature in the study area increased significantly; the rate of increase was 0.39∘ per decade. Among the climate factors, self-calibrated Palmer drought severity index (scPDSI) had the most significant impact on BAI. From P_May (P_ represents the month of the previous year) to December, BAI was always negatively correlated with the scPDSI, with 9 months being significantly negatively correlated. BAI was significantly positively correlated with the minimum 2 m temperature (TMN) in P_July, P_September, July, and September. BAI was significantly positively correlated with the maximum 2 m temperature (TMX) in P_October, P_December, and July. BAI was significantly positively correlated with the mean 2 m temperature (TMP) in P_July, P_December, and July. There is a significant positive correlation between BAI and annual NDVI (NDVIa), which means that NDVI can be used to study the response of plantations to climate change. Our study contributes to a better understanding of the response of plantation growth in high-altitude areas to climate change, which is needed by forest managers.
{"title":"Lengthening of the growth season, but no increased water availability, and increase in growth of Picea likiangensis var. rubescens plantations on eastern Tibetan Plateau due to climate change","authors":"Yu Feng, Songlin Shi, Peihao Peng, Qiang Zhou, Haijun Wang, Xiubin Liu","doi":"10.5194/we-22-47-2022","DOIUrl":"https://doi.org/10.5194/we-22-47-2022","url":null,"abstract":"Abstract. On the eastern Tibetan Plateau, the growth of trees is\u0000strongly affected by climate change. Previous researchers have found that\u0000climate warming changes thermal and hydraulic conditions, lengthening the\u0000growing season and promoting tree growth. Some studies have analyzed the\u0000effects of drought, precipitation, and temperature on tree growth. However,\u0000previous studies have mainly focused on natural forests, with few studies on\u0000the response of plantations to climate change. Therefore, we studied the\u0000relationship between dendrochronology (basal area increment, BAI),\u0000normalized difference vegetation index (NDVI), and climate factors to\u0000explore the response of Picea likiangensis var. rubescens plantations to climate change. The results\u0000showed that from 1990 to 2018, the temperature in the study area increased\u0000significantly; the rate of increase was 0.39∘ per decade. Among the\u0000climate factors, self-calibrated Palmer drought severity index (scPDSI) had\u0000the most significant impact on BAI. From P_May (P_ represents the month of\u0000the previous year) to December, BAI was always negatively correlated with\u0000the scPDSI, with 9 months being significantly negatively correlated. BAI\u0000was significantly positively correlated with the minimum 2 m temperature\u0000(TMN) in P_July, P_September, July, and September. BAI was significantly\u0000positively correlated with the maximum 2 m temperature (TMX) in P_October,\u0000P_December, and July. BAI was significantly positively correlated with the\u0000mean 2 m temperature (TMP) in P_July, P_December, and July. There is a\u0000significant positive correlation between BAI and annual NDVI (NDVIa), which\u0000means that NDVI can be used to study the response of plantations to climate\u0000change. Our study contributes to a better understanding of the response of\u0000plantation growth in high-altitude areas to climate change, which is needed\u0000by forest managers.\u0000","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"28 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79918425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Abdelghafar Alkishe, M. Cobos, L. Osorio-Olvera, A. Peterson
Abstract. Dermacentor marginatus is a vector disease of both humans and animals and transmits the causative agents of Q fever (Coxiella burnetii) and the spotted fever group (Rickettsia raoultii and R. slovaca), as well as of Crimean–Congo hemorrhagic fever. Dermacentor reticulatus can transmit various pathogens such as Francisella tularensis, Babesia spp., tick encephalitis virus, Coxiella burnetii, Omsk hemorrhagic fever virus, and Rickettsia spp. and can cause serious skin lesions. Herein, ecological niche modeling (ENM) is used to characterize the niches of these two ticks and describe their potential distributional patterns under both current and future climate conditions, as a means of highlighting geographic distributional shifts that may be of public health importance. We assessed distributional implications of five general circulation models (GCMs), under two shared socio-economic pathways (SSP245 and SSP585) for the period 2041–2060. Predictions for D. marginatus showed broad suitable areas across western, central, and southern Europe, with potential for expansion in northern and eastern Europe. Dermacentor reticulatus has suitable areas across western, central, and northern Europe. Under future scenarios, new expansions were observed in parts of northern and eastern Europe and highland areas in central Europe. Despite broad overlap between the niches of the ticks, D. marginatus has a broader niche, which allows it to show greater stability in the face of the changing climate conditions. Areas of potential geographic distributional expansion for these species should be monitored for actual distributional shifts, which may have implications for public health in those regions.
{"title":"Ecological niche and potential geographic distributions of Dermacentor marginatus and Dermacentor reticulatus (Acari: Ixodidae) under current and future climate conditions","authors":"Abdelghafar Alkishe, M. Cobos, L. Osorio-Olvera, A. Peterson","doi":"10.5194/we-22-33-2022","DOIUrl":"https://doi.org/10.5194/we-22-33-2022","url":null,"abstract":"Abstract. Dermacentor marginatus is a vector disease of both humans and animals and transmits the causative agents of Q fever (Coxiella burnetii) and the spotted fever group (Rickettsia raoultii and R. slovaca), as well as of Crimean–Congo hemorrhagic fever. Dermacentor reticulatus can transmit various pathogens such as Francisella tularensis, Babesia spp., tick encephalitis virus, Coxiella burnetii, Omsk hemorrhagic fever virus, and Rickettsia spp. and can cause serious skin lesions. Herein, ecological niche modeling (ENM) is used to characterize the niches of these two ticks and describe their potential distributional patterns under both current and future climate conditions, as a means of highlighting geographic distributional shifts that may be of public health importance. We assessed distributional implications of five general circulation models (GCMs), under two shared socio-economic pathways (SSP245 and SSP585) for the period 2041–2060. Predictions for D. marginatus showed broad suitable areas across western, central, and southern Europe, with potential for expansion in northern and eastern Europe. Dermacentor reticulatus has suitable areas across western, central, and northern Europe. Under future scenarios, new expansions were observed in parts of northern and eastern Europe and highland areas in central Europe. Despite broad overlap between the niches of the ticks, D. marginatus has a broader niche, which allows it to show greater stability in the face of the changing climate conditions. Areas of potential geographic distributional expansion for these species should be monitored for actual distributional shifts, which may have implications for public health in those regions.\u0000","PeriodicalId":54320,"journal":{"name":"Web Ecology","volume":"23 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89232268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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