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Matt Lavin - One of the best experts on this subject based on the ideXlab platform.
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evolutionary islands in the andes persistence and isolation explain high endemism in andean dry tropical forests
Journal of Biogeography, 2012Co-Authors: Toby R Pennington, Matt Lavin, Tiina Sarkinen, Marcelo F Simon, Colin E HughesAbstract:Aim The tropical Andes are a world biodiversity hotspot. With diverse Biomes and dramatic, geologically recent mountain uplift, they offer a system to study the relative contributions of geological and biome history to species richness. There are preliminary indications that historical species assembly in the Andes has been influenced by physiographical heterogeneity and that distinct Biomes have evolved in relative isolation despite physical proximity. Here we test this ‘Andean biotic separation hypothesis’ by focusing on the low-elevation, seasonally dry tropical forest (SDTF) biome to determine whether patterns of plant diversification within the SDTF differ from those in mid- and high-elevation Biomes. Location Tropical Andes, South America. Methods Densely sampled time-calibrated phylogenies for five legume genera (Amicia, Coursetia, Cyathostegia, Mimosa and Poissonia) containing species endemic to the Andean SDTF biome were used to investigate divergence times and levels of geographical structure. Geographical structure was measured using isolation-by-distance methods. Meta-analysis of time-calibrated phylogenies of Andean plant groups was used to compare the pattern and tempo of endemic species diversification between the major Andean Biomes. Results Long-term persistence of SDTF in the Andes is suggested by old stem ages (5–27 Ma) of endemic genera/clades within genera, and deep divergences coupled with strong geographical structure among and within species. Comparison of species diversification patterns among different Biomes shows that the relatively old, geographically confined pattern of species diversification in SDTF contrasts with the high-elevation grasslands that show rapid and recent radiations driven by ecological opportunities. Main conclusions The SDTF biome has a long history in the Andes. We suggest that the diverse SDTF flora has been assembled gradually over the past c. 19 Ma from lineages exhibiting strong phylogenetic niche conservatism. These patterns suggest that Andean SDTFs have formed stable and strongly isolated ‘islands’ despite the upheavals of Andean uplift. Indeed, the Andean SDTFs may represent some of the most isolated and evolutionarily persistent continental plant communities, similar in many respects to floras of remote oceanic islands.
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insights into the historical construction of species rich Biomes from dated plant phylogenies neutral ecological theory and phylogenetic community structure
New Phytologist, 2006Co-Authors: Toby R Pennington, James E Richardson, Matt LavinAbstract:Contents Summary 605 I. Introduction 606 II. Methodological issues 606 III. Insights into processes that give rise to species rich Biomes 608 IV. Future directions: neutral ecological theory, community phylogenetic structure, and processes leading to species accumulation 612 V. Conclusions 613 Acknowledgements 614 References 614 Summary Analytical methods are now available that can date all nodes in a molecular phylogenetic tree with one calibration, and which correct for variable rates of DNA substitution in different lineages. Although these techniques are approximate, they offer a new tool to investigate the historical construction of species-rich Biomes. Dated phylogenies of globally distributed plant families often indicate that dispersal, even across oceans, rather than plate tectonics, has generated their wide distributions. By contrast, there are indications that animal lineages have undergone less long distance dispersal. Dating the origin of biome-specific plant groups offers a means of estimating the age of the Biomes they characterize. However, rather than a simple emphasis on biome age, we stress the importance of studies that seek to unravel the processes that have led to the accumulation of large numbers of species in some Biomes. The synthesis of biological inventory, systematics and evolutionary biology offered by the frameworks of neutral ecological theory and phylogenetic community structure offers a promising route for future work.
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insights into the historical construction of species rich Biomes from dated plant phylogenies neutral ecological theory and phylogenetic community structure
New Phytologist, 2006Co-Authors: Toby R Pennington, James E Richardson, Matt LavinAbstract:Analytical methods are now available that can date all nodes in a molecular phylogenetic tree with one calibration, and which correct for variable rates of DNA substitution in different lineages. Although these techniques are approximate, they offer a new tool to investigate the historical construction of species-rich Biomes. Dated phylogenies of globally distributed plant families often indicate that dispersal, even across oceans, rather than plate tectonics, has generated their wide distributions. By contrast, there are indications that animal lineages have undergone less long distance dispersal. Dating the origin of biome-specific plant groups offers a means of estimating the age of the Biomes they characterize. However, rather than a simple emphasis on biome age, we stress the importance of studies that seek to unravel the processes that have led to the accumulation of large numbers of species in some Biomes. The synthesis of biological inventory, systematics and evolutionary biology offered by the frameworks of neutral ecological theory and phylogenetic community structure offers a promising route for future work.
Toby R Pennington - One of the best experts on this subject based on the ideXlab platform.
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evolutionary islands in the andes persistence and isolation explain high endemism in andean dry tropical forests
Journal of Biogeography, 2012Co-Authors: Toby R Pennington, Matt Lavin, Tiina Sarkinen, Marcelo F Simon, Colin E HughesAbstract:Aim The tropical Andes are a world biodiversity hotspot. With diverse Biomes and dramatic, geologically recent mountain uplift, they offer a system to study the relative contributions of geological and biome history to species richness. There are preliminary indications that historical species assembly in the Andes has been influenced by physiographical heterogeneity and that distinct Biomes have evolved in relative isolation despite physical proximity. Here we test this ‘Andean biotic separation hypothesis’ by focusing on the low-elevation, seasonally dry tropical forest (SDTF) biome to determine whether patterns of plant diversification within the SDTF differ from those in mid- and high-elevation Biomes. Location Tropical Andes, South America. Methods Densely sampled time-calibrated phylogenies for five legume genera (Amicia, Coursetia, Cyathostegia, Mimosa and Poissonia) containing species endemic to the Andean SDTF biome were used to investigate divergence times and levels of geographical structure. Geographical structure was measured using isolation-by-distance methods. Meta-analysis of time-calibrated phylogenies of Andean plant groups was used to compare the pattern and tempo of endemic species diversification between the major Andean Biomes. Results Long-term persistence of SDTF in the Andes is suggested by old stem ages (5–27 Ma) of endemic genera/clades within genera, and deep divergences coupled with strong geographical structure among and within species. Comparison of species diversification patterns among different Biomes shows that the relatively old, geographically confined pattern of species diversification in SDTF contrasts with the high-elevation grasslands that show rapid and recent radiations driven by ecological opportunities. Main conclusions The SDTF biome has a long history in the Andes. We suggest that the diverse SDTF flora has been assembled gradually over the past c. 19 Ma from lineages exhibiting strong phylogenetic niche conservatism. These patterns suggest that Andean SDTFs have formed stable and strongly isolated ‘islands’ despite the upheavals of Andean uplift. Indeed, the Andean SDTFs may represent some of the most isolated and evolutionarily persistent continental plant communities, similar in many respects to floras of remote oceanic islands.
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insights into the historical construction of species rich Biomes from dated plant phylogenies neutral ecological theory and phylogenetic community structure
New Phytologist, 2006Co-Authors: Toby R Pennington, James E Richardson, Matt LavinAbstract:Contents Summary 605 I. Introduction 606 II. Methodological issues 606 III. Insights into processes that give rise to species rich Biomes 608 IV. Future directions: neutral ecological theory, community phylogenetic structure, and processes leading to species accumulation 612 V. Conclusions 613 Acknowledgements 614 References 614 Summary Analytical methods are now available that can date all nodes in a molecular phylogenetic tree with one calibration, and which correct for variable rates of DNA substitution in different lineages. Although these techniques are approximate, they offer a new tool to investigate the historical construction of species-rich Biomes. Dated phylogenies of globally distributed plant families often indicate that dispersal, even across oceans, rather than plate tectonics, has generated their wide distributions. By contrast, there are indications that animal lineages have undergone less long distance dispersal. Dating the origin of biome-specific plant groups offers a means of estimating the age of the Biomes they characterize. However, rather than a simple emphasis on biome age, we stress the importance of studies that seek to unravel the processes that have led to the accumulation of large numbers of species in some Biomes. The synthesis of biological inventory, systematics and evolutionary biology offered by the frameworks of neutral ecological theory and phylogenetic community structure offers a promising route for future work.
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insights into the historical construction of species rich Biomes from dated plant phylogenies neutral ecological theory and phylogenetic community structure
New Phytologist, 2006Co-Authors: Toby R Pennington, James E Richardson, Matt LavinAbstract:Analytical methods are now available that can date all nodes in a molecular phylogenetic tree with one calibration, and which correct for variable rates of DNA substitution in different lineages. Although these techniques are approximate, they offer a new tool to investigate the historical construction of species-rich Biomes. Dated phylogenies of globally distributed plant families often indicate that dispersal, even across oceans, rather than plate tectonics, has generated their wide distributions. By contrast, there are indications that animal lineages have undergone less long distance dispersal. Dating the origin of biome-specific plant groups offers a means of estimating the age of the Biomes they characterize. However, rather than a simple emphasis on biome age, we stress the importance of studies that seek to unravel the processes that have led to the accumulation of large numbers of species in some Biomes. The synthesis of biological inventory, systematics and evolutionary biology offered by the frameworks of neutral ecological theory and phylogenetic community structure offers a promising route for future work.
Daniel Negreiros - One of the best experts on this subject based on the ideXlab platform.
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a global method for calculating plant csr ecological strategies applied across Biomes world wide
Functional Ecology, 2017Co-Authors: Simon Pierce, Daniel Negreiros, Bruno Enrico Leone Cerabolini, Jens Kattge, Sandra Diaz, Michael Kleyer, Bill Shipley, S J Wright, Nadejda A Soudzilovskaia, V G OnipchenkoAbstract:Summary Competitor, stress-tolerator, ruderal (CSR) theory is a prominent plant functional strategy scheme previously applied to local floras. Globally, the wide geographic and phylogenetic coverage of available values of leaf area (LA), leaf dry matter content (LDMC) and specific leaf area (SLA) (representing, respectively, interspecific variation in plant size and conservative vs. acquisitive resource economics) promises the general application of CSR strategies across Biomes, including the tropical forests hosting a large proportion of Earth's diversity. We used trait variation for 3068 tracheophytes (representing 198 families, six continents and 14 Biomes) to create a globally calibrated CSR strategy calculator tool and investigate strategy–environment relationships across Biomes world-wide. Due to disparity in trait availability globally, co-inertia analysis was used to check correspondence between a ‘wide geographic coverage, few traits’ data set and a ‘restricted coverage, many traits’ subset of 371 species for which 14 whole-plant, flowering, seed and leaf traits (including leaf nitrogen content) were available. CSR strategy/environment relationships within Biomes were investigated using fourth-corner and RLQ analyses to determine strategy/climate specializations. Strong, significant concordance (RV = 0·597; P < 0·0001) was evident between the 14 trait multivariate space and when only LA, LDMC and SLA were used. Biomes such as tropical moist broadleaf forests exhibited strategy convergence (i.e. clustered around a CS/CSR median; C:S:R = 43:42:15%), with CS-selection associated with warm, stable situations (lesser temperature seasonality), with greater annual precipitation and potential evapotranspiration. Other Biomes were characterized by strategy divergence: for example, deserts varied between xeromorphic perennials such as Larrea divaricata, classified as S-selected (C:S:R = 1:99:0%) and broadly R-selected annual herbs (e.g. Claytonia perfoliata; R/CR-selected; C:S:R = 21:0:79%). Strategy convergence was evident for several growth habits (e.g. trees) but not others (forbs). The CSR strategies of vascular plants can now be compared quantitatively within and between Biomes at the global scale. Through known linkages between underlying leaf traits and growth rates, herbivory and decomposition rates, this method and the strategy–environment relationships it elucidates will help to predict which kinds of species may assemble in response to changes in biogeochemical cycles, climate and land use.
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where tree planting and forest expansion are bad for biodiversity and ecosystem services
BioScience, 2015Co-Authors: Joseph W Veldman, Gerhard E Overbeck, Daniel Negreiros, Gregory Mahy, Soizig Le Stradic, Wilson G Fernandes, Giselda Durigan, Elise Buisson, Francis E Putz, William J BondAbstract:Misperceptions about the world's grassy Biomes contribute to their alarming rates of loss due to conversion for agriculture and tree plantations, as well as to forest encroachment. To illustrate the causes and consequences of these misperceptions, we show that the World Resources Institute and the International Union for Conservation of Nature misidentified 9 million square kilometers of ancient grassy Biomes as providing “Opportunities” for forest restoration. Establishment of forests in these grasslands, savannas, and open-canopy woodlands would devastate biodiversity and ecosystem services. Such undesired outcomes are avoidable if the distinct ecologies and conservation needs of forest and grassy Biomes become better integrated into science and policy. To start with, scientists should create maps that accurately depict grassy Biomes at global and landscape scales. It is also crucial that international environmental agreements (e.g., the United Nations Framework Convention on Climate Change) formally recognize grassy Biomes and their environmental values.
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Toward an old-growth concept for grasslands, savannas, and woodlands
Frontiers in Ecology and the Environment, 2015Co-Authors: Joseph W Veldman, Gerhard E Overbeck, Daniel Negreiros, Gregory Mahy, Giselda Durigan, Elise Buisson, G. Wilson Fernandes, Soizig Le Stradic, Robin G. Veldman, Nicholas P. ZaloumisAbstract:We expand the concept of “old growth” to encompass the distinct ecologies and conservation values of the world's ancient grass-dominated Biomes. Biologically rich grasslands, savannas, and open-canopy woodlands suffer from an image problem among scientists, policy makers, land managers, and the general public, that fosters alarming rates of ecosystem destruction and degradation. These Biomes have for too long been misrepresented as the result of deforestation followed by arrested succession. We now know that grassy Biomes originated millions of years ago, long before humans began deforesting. We present a consensus view from diverse geographic regions on the ecological characteristics needed to identify old-growth grasslands and to distinguish them from recently formed anthropogenic vegetation. If widely adopted, the old-growth grassland concept has the potential to improve scientific understanding, conservation policies, and ecosystem management.
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tyranny of trees in grassy Biomes
Science, 2015Co-Authors: Joseph W Veldman, Gerhard E Overbeck, Daniel Negreiros, Gregory Mahy, Soizig Le Stradic, Wilson G Fernandes, Giselda Durigan, Elise Buisson, Francis E PutzAbstract:![Figure][1] Highland grassland in Brazil is considered a forest landscape restoration opportunity PHOTO: G. W. FERNANDES Tree planting, fire suppression, and exclusion of megafaunal herbivores (native or domestic) are ecologically reasonable restoration strategies in deforested landscapes
Rien Aerts - One of the best experts on this subject based on the ideXlab platform.
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ecological consequences of the expansion of n2 fixing plants in cold Biomes
Oecologia, 2014Co-Authors: Erika Hiltbrunner, Rien Aerts, Tobias Buhlmann, Kerstin Hussdanell, Borgthor Magnusson, David D Myrold, Sasha C Reed, Bjarni D Sigurdsson, Christian KornerAbstract:Research in warm-climate Biomes has shown that invasion by symbiotic dinitrogen (N2)-fixing plants can transform ecosystems in ways analogous to the transformations observed as a consequence of anthropogenic, atmospheric nitrogen (N) deposition: declines in biodiversity, soil acidification, and alterations to carbon and nutrient cycling, including increased N losses through nitrate leaching and emissions of the powerful greenhouse gas nitrous oxide (N2O). Here, we used literature review and case study approaches to assess the evidence for similar transformations in cold-climate ecosystems of the boreal, subarctic and upper montane-temperate life zones. Our assessment focuses on the plant genera Lupinus and Alnus, which have become invasive largely as a consequence of deliberate introductions and/or reduced land management. These cold Biomes are commonly located in remote areas with low anthropogenic N inputs, and the environmental impacts of N2-fixer invasion appear to be as severe as those from anthropogenic N deposition in highly N polluted areas. Hence, inputs of N from N2 fixation can affect ecosystems as dramatically or even more strongly than N inputs from atmospheric deposition, and Biomes in cold climates represent no exception with regard to the risk of being invaded by N2-fixing species. In particular, the cold Biomes studied here show both a strong potential to be transformed by N2-fixing plants and a rapid subsequent saturation in the ecosystem’s capacity to retain N. Therefore, analogous to increases in N deposition, N2-fixing plant invasions must be deemed significant threats to biodiversity and to environmental quality.
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global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold Biomes
Ecology Letters, 2007Co-Authors: Johannes H C Cornelissen, Rien Aerts, Peter M Van Bodegom, Terry V Callaghan, Richard S P Van Logtestijn, Juha M Alatalo, Stuart F Chapin, Renato Gerdol, Jon Gudmundsson, Dylan GwynnjonesAbstract:Whether climate change will turn cold Biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern Biomes worldwide. Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold Biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.
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the freezer defrosting global warming and litter decomposition rates in cold Biomes
Journal of Ecology, 2006Co-Authors: Rien AertsAbstract:Summary 1 Decomposition of plant litter, a key component of the global carbon budget, is hierarchically controlled by the triad: climate > litter quality > soil organisms. Given the sensitivity of decomposition to temperature, especially in cold Biomes, it has been hypothesized that global warming will lead to increased litter decomposition rates, both through direct temperature effects and through indirect effects on litter quality and soil organisms. 2 A meta-analysis of experimental warming studies in cold Biomes (34 site-species combinations) showed that warming resulted in slightly increased decomposition rates. However, this response was strongly dependent on the method used: open top chambers reduced decomposition rates, whereas heating lamps stimulated decomposition rates. The low responsiveness was mainly due to moisture-limited decomposition rates in the warming treatments, especially at mesic and xeric sites. This control of litter decomposition by both temperature and moisture was corroborated by natural gradient studies. 3 Interspecific differences in litter quality and decomposability are substantially larger than warming-induced phenotypic responses. Thus, the changes in the species composition and structure of plant communities that have been observed in medium-term warming studies in cold Biomes will have a considerably greater impact on ecosystem litter decomposition than phenotypic responses. 4 Soil fauna communities in cold Biomes are responsive to climate warming. Moreover, temperature-driven migration of the, hitherto absent, large comminuters to highlatitude sites may significantly increase decomposition rates. However, we do not know how far-reaching the consequences of changes in the species composition and structure of the soil community are for litter decomposition, as there is a lack of data on functional species redundancy and the species’ dispersal ability. 5 Global warming will lead to increased litter decomposition rates only if there is sufficient soil moisture. Hence, climate scenario and experimental studies should focus more on both factors and their interaction. As interspecific differences in potential decomposability and litter chemistry are substantially larger than phenotypic responses to warming, the focus of future research should be on the former. In addition, more light should be shed on the below-ground ‘darkness’ to evaluate the ecological significance of warming-induced soil fauna community changes for litter decomposition processes in cold Biomes.
Alba Gutiérrez-girón - One of the best experts on this subject based on the ideXlab platform.
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Early stage litter decomposition across Biomes
Science of the Total Environment, 2018Co-Authors: Ika Djukic, Kris Verheyen, Sebastian Kepfer-rojas, Inge Schmidt, Klaus Steenberg Klaus, Claus Beier, Adriano Adrian, Alain Paquette, Alba Gutiérrez-girónAbstract:Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from