Pub Date : 2020-07-03DOI: 10.1080/17550874.2020.1800119
P. Becerra, L. Cavieres, R. Bustamante
ABSTRACT Background The effects of many invasive species on invaded communities are still scarcely known. Centaurea solstitialis is an invasive Eurasian herb, widely distributed around the world, but its effects on recipient communities are not well known. Aims To evaluate the effect of C. solstitialis invasion on richness and cover of native and exotic resident species in naturally established communities. Methods We repeated a field experiment in three old-fields of central Chile where C. solstitialis was not present. The experiment simulated the invasion of C. solstitialis by adding 600 seeds per plots of 1 × 1 m in size and compared the richness and cover of all naturally growing species in plots with and without C. solstitialis. Results For exotics, initial species richness (average ca.18% and 20% per site), and cover (average ca. 20% and 34% per site) were significantly reduced by C. solstitialis in two out of the three sites. The abundances of four out of 17 exotic resident species were negatively affected by C. solstitialis. Native species were not affected by C. solstitialis. Conclusions C. solstitialis can outcompete resident species of communities where it invades, but local ecological factors influence its effects producing different impacts among species and localities.
{"title":"Effect of the invasive exotic herb Centaurea solstitialis on plant communities of a semiarid ecosystem","authors":"P. Becerra, L. Cavieres, R. Bustamante","doi":"10.1080/17550874.2020.1800119","DOIUrl":"https://doi.org/10.1080/17550874.2020.1800119","url":null,"abstract":"ABSTRACT Background The effects of many invasive species on invaded communities are still scarcely known. Centaurea solstitialis is an invasive Eurasian herb, widely distributed around the world, but its effects on recipient communities are not well known. Aims To evaluate the effect of C. solstitialis invasion on richness and cover of native and exotic resident species in naturally established communities. Methods We repeated a field experiment in three old-fields of central Chile where C. solstitialis was not present. The experiment simulated the invasion of C. solstitialis by adding 600 seeds per plots of 1 × 1 m in size and compared the richness and cover of all naturally growing species in plots with and without C. solstitialis. Results For exotics, initial species richness (average ca.18% and 20% per site), and cover (average ca. 20% and 34% per site) were significantly reduced by C. solstitialis in two out of the three sites. The abundances of four out of 17 exotic resident species were negatively affected by C. solstitialis. Native species were not affected by C. solstitialis. Conclusions C. solstitialis can outcompete resident species of communities where it invades, but local ecological factors influence its effects producing different impacts among species and localities.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"267 - 275"},"PeriodicalIF":1.5,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1800119","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47931787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-03DOI: 10.1080/17550874.2020.1765037
M. Ruhsam, D. Kohn, J. Squirrell, Harald Schneider, J. Vogel, F. Rumsey, P. Hollingsworth
ABSTRACT Background There is considerable concern that the native British bluebell Hyacinthoides non-scripta (Asparagaceae) is at risk due to hybridisation with naturalised British non-native bluebells. However, the taxonomic identity of British non-natives is uncertain, and they are either referred to as Spanish bluebells, H. hispanica, or as hybrids between H. non-scripta and H. hispanica. Aims To establish whether a detailed morphological analysis can shed light on the taxonomic identity of non-native British bluebells. Methods We measured 28 morphological characters and recorded the pollen fertility of native and non-native bluebells in Britain and compared these with H. hispanica populations from Portugal. Results British non-native bluebells appeared morphologically close to H. hispanica but occupied a separate phenotypic space. All three taxa showed high morphological variability with overlapping ranges, however, at least 92.8% of trait means were significantly different between any pair-wise taxon comparison. Sixty per cent of continuous traits were significantly larger in British non-native bluebells compared to H. non-scripta and H. hispanica. In contrast, pollen fertility was significantly lower in British non-natives (79%) compared to H. non-scripta (94%) and H. hispanica (84%). Conclusions These results are consistent with, however, do not provide conclusive evidence for, the possible hybrid status of British non-native bluebells.
{"title":"Morphology and pollen fertility of native and non-native bluebells in Great Britain","authors":"M. Ruhsam, D. Kohn, J. Squirrell, Harald Schneider, J. Vogel, F. Rumsey, P. Hollingsworth","doi":"10.1080/17550874.2020.1765037","DOIUrl":"https://doi.org/10.1080/17550874.2020.1765037","url":null,"abstract":"ABSTRACT Background There is considerable concern that the native British bluebell Hyacinthoides non-scripta (Asparagaceae) is at risk due to hybridisation with naturalised British non-native bluebells. However, the taxonomic identity of British non-natives is uncertain, and they are either referred to as Spanish bluebells, H. hispanica, or as hybrids between H. non-scripta and H. hispanica. Aims To establish whether a detailed morphological analysis can shed light on the taxonomic identity of non-native British bluebells. Methods We measured 28 morphological characters and recorded the pollen fertility of native and non-native bluebells in Britain and compared these with H. hispanica populations from Portugal. Results British non-native bluebells appeared morphologically close to H. hispanica but occupied a separate phenotypic space. All three taxa showed high morphological variability with overlapping ranges, however, at least 92.8% of trait means were significantly different between any pair-wise taxon comparison. Sixty per cent of continuous traits were significantly larger in British non-native bluebells compared to H. non-scripta and H. hispanica. In contrast, pollen fertility was significantly lower in British non-natives (79%) compared to H. non-scripta (94%) and H. hispanica (84%). Conclusions These results are consistent with, however, do not provide conclusive evidence for, the possible hybrid status of British non-native bluebells.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"351 - 361"},"PeriodicalIF":1.5,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1765037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42972707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-03DOI: 10.1080/17550874.2020.1832154
A. M. Abbas, A. Rubio-Casal, A. de Cires, E. Figueroa, A. Pickart, J. Castillo
ABSTRACT Background Germination and especially emergence can decrease significantly with depth. Aim Our main goal was to examine the effects of sand burial depth on seed germination and seedling establishment of two halophytes, Spartina densiflora and Atriplex portulacoides, with contrasted fruit traits. Methods The effects of sand burial to depths of 0 to 6 cm on seed germination and seedling establishment were studied in a greenhouse experiment. Sediment erosion/accretion dynamics were also recorded at a salt marsh colonised recently by both species. Results Germination percentage for both halophytes was higher at a depth of 1 cm than at the surface, and decreased gradually with increasing depth below 1 cm. Emergence of seedlings was similar between 1 and 3 cm (ca. 20–60 %) for both species. The highest seedling survival rates (ca. 100 %) were recorded for seeds sown at a depth of 2 cm for S. densiflora and between 1 and 3 cm for A. portulacoides. Recorded erosion and accretion rates was large enough to modify germination and establishment patterns in both halophytes. Conclusions Spartina densiflora showed higher germination rates than A. portulacoides at greater depths, which seemed to be related to its growth form.
{"title":"Burial effects on seed germination and seedling emergence of two halophytes of contrasting seed size","authors":"A. M. Abbas, A. Rubio-Casal, A. de Cires, E. Figueroa, A. Pickart, J. Castillo","doi":"10.1080/17550874.2020.1832154","DOIUrl":"https://doi.org/10.1080/17550874.2020.1832154","url":null,"abstract":"ABSTRACT Background Germination and especially emergence can decrease significantly with depth. Aim Our main goal was to examine the effects of sand burial depth on seed germination and seedling establishment of two halophytes, Spartina densiflora and Atriplex portulacoides, with contrasted fruit traits. Methods The effects of sand burial to depths of 0 to 6 cm on seed germination and seedling establishment were studied in a greenhouse experiment. Sediment erosion/accretion dynamics were also recorded at a salt marsh colonised recently by both species. Results Germination percentage for both halophytes was higher at a depth of 1 cm than at the surface, and decreased gradually with increasing depth below 1 cm. Emergence of seedlings was similar between 1 and 3 cm (ca. 20–60 %) for both species. The highest seedling survival rates (ca. 100 %) were recorded for seeds sown at a depth of 2 cm for S. densiflora and between 1 and 3 cm for A. portulacoides. Recorded erosion and accretion rates was large enough to modify germination and establishment patterns in both halophytes. Conclusions Spartina densiflora showed higher germination rates than A. portulacoides at greater depths, which seemed to be related to its growth form.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"339 - 349"},"PeriodicalIF":1.5,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1832154","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45027347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-03DOI: 10.1080/17550874.2020.1819464
P. Grubb, J. R. Lloyd, T. D. Pennington, Sebastián Páez‐Bimos
ABSTRACT Background We report the vegetation at 4050–4600 m in 1960 on the western slopes of Antisana, Ecuador, decades before burning and grazing were prohibited. Aim: To provide a baseline against which new surveys could be compared to evaluate conservation efforts. Methods We (a) ordinated grassland types and derived communities using constancy values of species in typical stands, (b) recorded evidence of community dynamics, (c) recorded the composition of communities occupying smaller areas than the grassy páramo, and (d) recorded inhibition and facilitation of other species by Azorella cushions. Results Short-turf grassland had replaced much tall-tussock grassland as a result of grazing and burning. Intense trampling had resulted in dominance by an introduced annual grass. Disturbance of most tall-tussock grassland on lava flows had left gaps made by fire or rabbit-scratching; these were invaded by distinctive sets of species. Azonal communities, changed much less by humans, contained 63% of 155 native species of vascular plant encountered, and 68% of 65 mosses. Younger cushions of Azorella impacted negatively on associated species but older cushions had facilitative effects. Conclusions Our study provides an adequate record against which to determine the extent and nature of changes in the vegetation since farming of livestock ceased.
{"title":"A historical baseline study of the páramo of Antisana in the Ecuadorian Andes including the impacts of burning, grazing and trampling","authors":"P. Grubb, J. R. Lloyd, T. D. Pennington, Sebastián Páez‐Bimos","doi":"10.1080/17550874.2020.1819464","DOIUrl":"https://doi.org/10.1080/17550874.2020.1819464","url":null,"abstract":"ABSTRACT Background We report the vegetation at 4050–4600 m in 1960 on the western slopes of Antisana, Ecuador, decades before burning and grazing were prohibited. Aim: To provide a baseline against which new surveys could be compared to evaluate conservation efforts. Methods We (a) ordinated grassland types and derived communities using constancy values of species in typical stands, (b) recorded evidence of community dynamics, (c) recorded the composition of communities occupying smaller areas than the grassy páramo, and (d) recorded inhibition and facilitation of other species by Azorella cushions. Results Short-turf grassland had replaced much tall-tussock grassland as a result of grazing and burning. Intense trampling had resulted in dominance by an introduced annual grass. Disturbance of most tall-tussock grassland on lava flows had left gaps made by fire or rabbit-scratching; these were invaded by distinctive sets of species. Azonal communities, changed much less by humans, contained 63% of 155 native species of vascular plant encountered, and 68% of 65 mosses. Younger cushions of Azorella impacted negatively on associated species but older cushions had facilitative effects. Conclusions Our study provides an adequate record against which to determine the extent and nature of changes in the vegetation since farming of livestock ceased.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"225 - 256"},"PeriodicalIF":1.5,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1819464","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43575634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-03DOI: 10.1080/17550874.2020.1762133
C. Delgado, M. Feio, I. Pardo, S. Almeida
ABSTRACT Background Thermal springs provide extreme ecological conditions for aquatic communities owing to their high water temperature and particular water chemistry. The thermal springs and their connected watercourses provide a thermal laboratory by offering a wide range of temperatures within short spatial distances. To date, the information on how the biodiversity of these springs is related to water temperature or chemistry is limited. Aims We studied the effects of water temperature on diatom community diversity and structure with the objective to supply a baseline for the conservation of thermal springs. Methods We sampled 31 sites of 16 thermal springs across a temperature gradient between 18.5 and 63.0°C in the north-western Iberian Peninsula and related diatom richness and structure to water temperature. Results A total of 124 diatom species were identified in springs with water temperature between 18.5 and 42.4°C. Community diversity decreased with increasing temperature and the highest species richness was found at temperatures ≤ 25°C. Three diatom assemblages were defined, discriminated by temperature ranges (≤25°C, 25–35°C and ≥35°C). Conclusions Water temperature was found to be an important driver of diatom community composition in the thermal systems studied. Temperature affects diatom distribution decreasing diversity with the increase in global water temperature.
{"title":"Effects of water temperature over benthic diatom communities: insights from thermal springs","authors":"C. Delgado, M. Feio, I. Pardo, S. Almeida","doi":"10.1080/17550874.2020.1762133","DOIUrl":"https://doi.org/10.1080/17550874.2020.1762133","url":null,"abstract":"ABSTRACT Background Thermal springs provide extreme ecological conditions for aquatic communities owing to their high water temperature and particular water chemistry. The thermal springs and their connected watercourses provide a thermal laboratory by offering a wide range of temperatures within short spatial distances. To date, the information on how the biodiversity of these springs is related to water temperature or chemistry is limited. Aims We studied the effects of water temperature on diatom community diversity and structure with the objective to supply a baseline for the conservation of thermal springs. Methods We sampled 31 sites of 16 thermal springs across a temperature gradient between 18.5 and 63.0°C in the north-western Iberian Peninsula and related diatom richness and structure to water temperature. Results A total of 124 diatom species were identified in springs with water temperature between 18.5 and 42.4°C. Community diversity decreased with increasing temperature and the highest species richness was found at temperatures ≤ 25°C. Three diatom assemblages were defined, discriminated by temperature ranges (≤25°C, 25–35°C and ≥35°C). Conclusions Water temperature was found to be an important driver of diatom community composition in the thermal systems studied. Temperature affects diatom distribution decreasing diversity with the increase in global water temperature.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"325 - 337"},"PeriodicalIF":1.5,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1762133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41478570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-03DOI: 10.1080/17550874.2020.1817998
Sheherezade N. Adams, S. Jennings, Nils Warnock
ABSTRACT Background Invasive plants are associated with the decline of native plant richness, but the impact of removal of invasives on native plant richness is often unknown. Aims We investigated whether the presence of the introduced plant Centaurea solstitialis (Asteraceae) was correlated with reduced native plant richness; whether rain in late spring, when C. solstitialis is virtually the only plant actively growing, increased its cover; and whether native species richness increased following the control of C. solstitialis. Methods From 2011 to 2017 in a grassland in Sonoma County, California, USA, we treated 20 1-m2 plots in C. solstitialis-invaded patches with chemical and mechanical removal. We monitored cover of all plants in those plots, plus 20 invaded untreated and 20 uninvaded plots, for a total of 60 plots in two blocks. Results Native plant richness was lower in invaded than in non-invaded plots. More late spring rainfall resulted in greater C. solstitialis cover in the following year. Native species richness in the six years after initial removal was slightly higher in removal plots than in untreated control plots. Conclusions Centaurea solstitialis removal alone results in modest benefits for native plant species richness. Managing this invasive requires more resources in years with more late spring rainfall.
{"title":"Plant invasion depresses native species richness, but control of invasive species does little to restore it","authors":"Sheherezade N. Adams, S. Jennings, Nils Warnock","doi":"10.1080/17550874.2020.1817998","DOIUrl":"https://doi.org/10.1080/17550874.2020.1817998","url":null,"abstract":"ABSTRACT Background Invasive plants are associated with the decline of native plant richness, but the impact of removal of invasives on native plant richness is often unknown. Aims We investigated whether the presence of the introduced plant Centaurea solstitialis (Asteraceae) was correlated with reduced native plant richness; whether rain in late spring, when C. solstitialis is virtually the only plant actively growing, increased its cover; and whether native species richness increased following the control of C. solstitialis. Methods From 2011 to 2017 in a grassland in Sonoma County, California, USA, we treated 20 1-m2 plots in C. solstitialis-invaded patches with chemical and mechanical removal. We monitored cover of all plants in those plots, plus 20 invaded untreated and 20 uninvaded plots, for a total of 60 plots in two blocks. Results Native plant richness was lower in invaded than in non-invaded plots. More late spring rainfall resulted in greater C. solstitialis cover in the following year. Native species richness in the six years after initial removal was slightly higher in removal plots than in untreated control plots. Conclusions Centaurea solstitialis removal alone results in modest benefits for native plant species richness. Managing this invasive requires more resources in years with more late spring rainfall.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"257 - 266"},"PeriodicalIF":1.5,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1817998","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41479175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-03DOI: 10.1080/17550874.2020.1819465
D. Spennemann
ABSTRACT Background Dispersed by the horticultural industry, Washingtonia filifera and W. robusta have become one of the most ubiquitous ornamental palm species throughout all temperate zones. Aims This paper systematically reviews the state of knowledge of the ecological provisioning services provided by these palms. Methods Review of the extant literature based on a combination of systematic database searches with snowballing. Results Globally, Washingtonia are a major urban food source for native and invasive animal species. The majority of vectors contribute little to medium-or long-range dispersal. Avian and terrestrial species with a high connective potential facilitate long-distance dispersal. The dead leaves surrounding the stem serve as habitat for numerous native and invasive species. Conclusions The horticultural plantings of Washingtonia in areas adjacent to but contiguous with their endemic range have allowed a number of user species to expand their range, with one example (Icterus cucullatus) in excess of 1000 km. In non-contiguous areas of introduction (e.g. Europe, Middle East, South Africa or Australia) several species native to those ecosystems have adapted to feeding on Washingtonia drupes, but only few species have adapted to using Washingtonia as habitat.
{"title":"Palms fanning out: a review of the ecological provisioning services provided by Washingtonia filifera and W. robusta in their native and exotic settings","authors":"D. Spennemann","doi":"10.1080/17550874.2020.1819465","DOIUrl":"https://doi.org/10.1080/17550874.2020.1819465","url":null,"abstract":"ABSTRACT Background Dispersed by the horticultural industry, Washingtonia filifera and W. robusta have become one of the most ubiquitous ornamental palm species throughout all temperate zones. Aims This paper systematically reviews the state of knowledge of the ecological provisioning services provided by these palms. Methods Review of the extant literature based on a combination of systematic database searches with snowballing. Results Globally, Washingtonia are a major urban food source for native and invasive animal species. The majority of vectors contribute little to medium-or long-range dispersal. Avian and terrestrial species with a high connective potential facilitate long-distance dispersal. The dead leaves surrounding the stem serve as habitat for numerous native and invasive species. Conclusions The horticultural plantings of Washingtonia in areas adjacent to but contiguous with their endemic range have allowed a number of user species to expand their range, with one example (Icterus cucullatus) in excess of 1000 km. In non-contiguous areas of introduction (e.g. Europe, Middle East, South Africa or Australia) several species native to those ecosystems have adapted to feeding on Washingtonia drupes, but only few species have adapted to using Washingtonia as habitat.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"289 - 324"},"PeriodicalIF":1.5,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1819465","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46425159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-19DOI: 10.1080/17550874.2020.1762134
Meredith D. Jabis, M. Germino, L. Kueppers
ABSTRACT Background: Climate change is projected to alter the elevation and latitude of treeline globally. Seed germination and seedling survival are critical controls on treeline expansion. Neighbouring alpine plants, either through competition for resources or through altered microclimate, also affect seedlings emerging in the alpine zone. With warming, alpine plant species may interact with each other more or less strongly. Aims: To determine whether establishing tree seedlings and an alpine herb are similarly sensitive to alpine plant neighbours under ambient and altered climate. Methods: We imposed active heating, watering, and removed all plants adjacent to emerging conifer seedlings and an alpine herb. Results: Picea engelmannii seedlings showed lower survival compared with Pinus flexilis 3 weeks following neighbour removal, and after 1 year only survived in watered plots. Pinus seedlings responded to neighbour removal by lowering the quantum yield of photosynthesis (ϕPSII). Contrary to expectations from the stress gradient hypothesis, survival was reduced without neighbours near the low-elevation range limit of Chionophila jamesii. Conclusions: Pinus flexilis has higher expansion potential into the alpine, while Picea engelmannii requires moist conditions that could be facilitated by neighbours to expand its range. This implies likely range expansion by P. flexilis with consequences for alpine plant diversity and ecosystem function.
{"title":"Colonisation of the alpine tundra by trees: alpine neighbours assist late-seral but not early-seral conifer seedlings","authors":"Meredith D. Jabis, M. Germino, L. Kueppers","doi":"10.1080/17550874.2020.1762134","DOIUrl":"https://doi.org/10.1080/17550874.2020.1762134","url":null,"abstract":"ABSTRACT Background: Climate change is projected to alter the elevation and latitude of treeline globally. Seed germination and seedling survival are critical controls on treeline expansion. Neighbouring alpine plants, either through competition for resources or through altered microclimate, also affect seedlings emerging in the alpine zone. With warming, alpine plant species may interact with each other more or less strongly. Aims: To determine whether establishing tree seedlings and an alpine herb are similarly sensitive to alpine plant neighbours under ambient and altered climate. Methods: We imposed active heating, watering, and removed all plants adjacent to emerging conifer seedlings and an alpine herb. Results: Picea engelmannii seedlings showed lower survival compared with Pinus flexilis 3 weeks following neighbour removal, and after 1 year only survived in watered plots. Pinus seedlings responded to neighbour removal by lowering the quantum yield of photosynthesis (ϕPSII). Contrary to expectations from the stress gradient hypothesis, survival was reduced without neighbours near the low-elevation range limit of Chionophila jamesii. Conclusions: Pinus flexilis has higher expansion potential into the alpine, while Picea engelmannii requires moist conditions that could be facilitated by neighbours to expand its range. This implies likely range expansion by P. flexilis with consequences for alpine plant diversity and ecosystem function.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"209 - 224"},"PeriodicalIF":1.5,"publicationDate":"2020-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1762134","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44107922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-01DOI: 10.1080/17550874.2020.1729887
M. Wei, Shu Wang, Hong-guang Xiao, Bing-de Wu, K. Jiang, D. Du, Cong-yan Wang
ABSTRACT Background: Soil N2-fixing bacterial (SNB) communities may play a vital role in plant invasion. Two or more invasive plant species (invaders) may coexist in the same ecosystem. Thus, it is important to assess the effects of co-invasion on SNB communities to elucidate the ecological mechanisms of plant invasion. Aims: The effects of two co-occurring invaders (Erigeron annuus and Solidago canadensis) with different coverage classes on SNB communities were evaluated via a comparative study. Methods: SNB communities were assessed using a high-throughput sequencing approach. Results: The invasion of E. annuus and/or S. canadensis, regardless of coverage, did not pose pronounced effects on soil physicochemical properties and the diversity of SNB. Soil electrical conductivity was the most important environmental factors explaining the variation in SNB composition. This phenomenon may be chiefly attributed to the fact that the shifts in soil electrical conductivity can recruit obvious variations in the resource utilisation and acquisition patterns of carbon for the metabolism of soil microorganisms. Plant Shannon’s diversity was also one key factor influencing the community structure of SNB, but its direct effects are less powerful than soil electrical conductivity. However, the negatively indirect effects of plant Shannon’s diversity on the Shannon index, ACE index, and Chao1 index of SNB were noticeably greater than soil electrical conductivity. Therefore, the effects of plant Shannon’s diversity on the community structure of SNB may largely be attributed to the variation in soil electrical conductivity via the released root exudates and then modify the resource availability pattern of SNB. Conclusions: SNB diversity is more influenced by changes in soil variables like soil electrical conductivity than by the presence/coverage of invasive plant species.
{"title":"Stand-alone or co-occurring invasive plant species do not modify the diversity of the soil N2-fixing bacterial community","authors":"M. Wei, Shu Wang, Hong-guang Xiao, Bing-de Wu, K. Jiang, D. Du, Cong-yan Wang","doi":"10.1080/17550874.2020.1729887","DOIUrl":"https://doi.org/10.1080/17550874.2020.1729887","url":null,"abstract":"ABSTRACT Background: Soil N2-fixing bacterial (SNB) communities may play a vital role in plant invasion. Two or more invasive plant species (invaders) may coexist in the same ecosystem. Thus, it is important to assess the effects of co-invasion on SNB communities to elucidate the ecological mechanisms of plant invasion. Aims: The effects of two co-occurring invaders (Erigeron annuus and Solidago canadensis) with different coverage classes on SNB communities were evaluated via a comparative study. Methods: SNB communities were assessed using a high-throughput sequencing approach. Results: The invasion of E. annuus and/or S. canadensis, regardless of coverage, did not pose pronounced effects on soil physicochemical properties and the diversity of SNB. Soil electrical conductivity was the most important environmental factors explaining the variation in SNB composition. This phenomenon may be chiefly attributed to the fact that the shifts in soil electrical conductivity can recruit obvious variations in the resource utilisation and acquisition patterns of carbon for the metabolism of soil microorganisms. Plant Shannon’s diversity was also one key factor influencing the community structure of SNB, but its direct effects are less powerful than soil electrical conductivity. However, the negatively indirect effects of plant Shannon’s diversity on the Shannon index, ACE index, and Chao1 index of SNB were noticeably greater than soil electrical conductivity. Therefore, the effects of plant Shannon’s diversity on the community structure of SNB may largely be attributed to the variation in soil electrical conductivity via the released root exudates and then modify the resource availability pattern of SNB. Conclusions: SNB diversity is more influenced by changes in soil variables like soil electrical conductivity than by the presence/coverage of invasive plant species.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"277 - 287"},"PeriodicalIF":1.5,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1729887","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48324256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-03DOI: 10.1080/17550874.2020.1735553
Helen J. Millner, S. Bachman, T. C. Baldwin
ABSTRACT Background The genus Restrepia occurs throughout Central and South America in areas of montane forest heavily affected by deforestation. Aims The current study was designed to test the feasibility of using available online resources to establish the threats facing these orchids and their conservation status for later inclusion in the IUCN online database. Methods Online resources were searched for primary data on the distribution of species of Restrepia. The Geospatial Conservation Assessment Tool (GeoCAT) was used to produce semi-automated IUCN Red List assessments. Locations of populations were examined in Google Earth to establish habitat loss. A comparison of the data produced a Red List assessment for each species. Results The observed losses of Restrepia habitat were: Venezuela 45% of recorded locations for 15 species, Colombia 28% for 30 species, Ecuador 36% for 18 species, Peru 41% for eight species, Costa Rica 81% and Panama 32% for three species. This habitat loss coincided with the route of the Pan-American Highway in these countries. Conclusions It was possible to establish the Red List Status of Restrepia species even with minimal data. The degree of threat facing these and other epiphytic orchid genera in these habitats was shown to be considerable.
{"title":"An assessment of the conservation status of Restrepia (Orchidaceae) reveals the threatened status of the genus","authors":"Helen J. Millner, S. Bachman, T. C. Baldwin","doi":"10.1080/17550874.2020.1735553","DOIUrl":"https://doi.org/10.1080/17550874.2020.1735553","url":null,"abstract":"ABSTRACT Background The genus Restrepia occurs throughout Central and South America in areas of montane forest heavily affected by deforestation. Aims The current study was designed to test the feasibility of using available online resources to establish the threats facing these orchids and their conservation status for later inclusion in the IUCN online database. Methods Online resources were searched for primary data on the distribution of species of Restrepia. The Geospatial Conservation Assessment Tool (GeoCAT) was used to produce semi-automated IUCN Red List assessments. Locations of populations were examined in Google Earth to establish habitat loss. A comparison of the data produced a Red List assessment for each species. Results The observed losses of Restrepia habitat were: Venezuela 45% of recorded locations for 15 species, Colombia 28% for 30 species, Ecuador 36% for 18 species, Peru 41% for eight species, Costa Rica 81% and Panama 32% for three species. This habitat loss coincided with the route of the Pan-American Highway in these countries. Conclusions It was possible to establish the Red List Status of Restrepia species even with minimal data. The degree of threat facing these and other epiphytic orchid genera in these habitats was shown to be considerable.","PeriodicalId":49691,"journal":{"name":"Plant Ecology & Diversity","volume":"13 1","pages":"115 - 131"},"PeriodicalIF":1.5,"publicationDate":"2020-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17550874.2020.1735553","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41341051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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