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Stefan A Schnitzer - One of the best experts on this subject based on the ideXlab platform.
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Lianas do not reduce tree biomass accumulation in young successional tropical dry forests
Oecologia, 2021Co-Authors: Sergio Estrada-villegas, Michiel Van Breugel, Jefferson S Hall, Stefan A SchnitzerAbstract:Young successional tropical forests are crucial in the global carbon cycle because they can quickly sequester large quantities of atmospheric carbon. However, Lianas (woody vines) can significantly decrease biomass accumulation in young regenerating forests. Lianas are abundant in tropical dry forests, and thus we hypothesized that Lianas reduce biomass accretion in dry forests. Lianas may be particularly detrimental to the growth of young trees, which are vulnerable to competition from Lianas. Alternatively, Lianas may have a stronger negative effect on the largest trees because Lianas seek the high-light environment at the top of the forest canopy. We tested these hypotheses using a liana-removal experiment in 13 dry forest stands that ranged from 1 to 70 years in southwestern Panama. We measured biomass accumulation annually for more than 10,000 stems from 2013 to 2017. Contrary to our expectations, liana removal had no effect on tree biomass accumulation across our successional forests and throughout our study period. Liana removal did not benefit smaller trees or larger trees. Lianas did not increase biomass accumulation on recruits, and did not increase biomass loss due to mortality. Surprisingly, removing Lianas had a negative effect on three out of 41 tree species. Lianas had no effect on biomass accumulation and loss, possibly because: (1) trees allocated resources to roots instead of stems, (2) trees and Lianas partitioned water, (3) higher irradiance after liana removal reduced soil moisture, or (4) low water availability might have been such a strong stressor that it reduced plant–plant competition.
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Lianas maintain insectivorous bird abundance and diversity in a neotropical forest
Ecology, 2020Co-Authors: Stefan A Schnitzer, Jennifer S Powers, Nicole L Michel, Douglas W RobinsonAbstract:The spatial habitat heterogeneity hypothesis posits that habitat complexity increases the abundance and diversity of species. In tropical forests, Lianas add substantial habitat heterogeneity and complexity throughout the vertical forest profile, which may maintain animal abundance and diversity. The effects of Lianas on tropical animal communities, however, remain poorly understood. We propose that Lianas have a positive effect on animals by enhancing habitat complexity. Lianas may have a particularly strong influence on the forest bird community, providing nesting substrate, protection from predators, and nutrition (food). Understory insectivorous birds, which forage for insects that specialize on Lianas, may particularly benefit. Alternatively, it is possible that Lianas have a negative effect on forest birds by increasing predator abundances and providing arboreal predators with travel routes with easy access to bird nests. We tested the spatial habitat heterogeneity hypothesis on bird abundance and diversity by removing Lianas, thus reducing forest complexity, using a large-scale experimental approach in a lowland tropical forest in the Republic of Panama. We found that removing Lianas decreased total bird abundance by 78.4% and diversity by 77.4% after 8 months, and by 40.0% and 51.7%, respectively, after 20 months. Insectivorous bird abundance and diversity 8 months after liana removal were 91.8% and 89.5% lower, respectively, indicating that Lianas positively influence insectivorous birds. The effects of liana removal persisted longer for insectivorous birds than other birds, with 77.3% lower abundance and 76.2% lower diversity after 20 months. Liana removal also altered bird community composition, creating two distinct communities in the control and removal plots, with disproportionate effects on insectivores. Our findings demonstrate that Lianas have a strong positive influence on the bird community, particularly for insectivorous birds in the forest understory. Lianas may maintain bird abundance and diversity by increasing habitat complexity, habitat heterogeneity, and resource availability.
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Lianas reduce biomass accumulation in early successional tropical forests
Ecology, 2020Co-Authors: Stefan A Schnitzer, Sergio Estradavillegas, Jefferson S Hall, Michiel Van BreugelAbstract:Early successional tropical forests could mitigate climate change via rapid accumulation of atmospheric carbon. However, liana (woody vine) abundance and biomass has been increasing in many tropical forests over the past decades, which may slow the speed at which secondary forests accumulate biomass. Lianas decrease biomass accumulation in tropical forests, and may have a particularly strong effect on young forests by stalling tree growth. As forests mature, trees may outgrow or shed Lianas, thus escaping some of the negative effects of Lianas. Alternatively, Lianas may have the strongest effect in older successional forests if the effect of Lianas is commensurate with their density, which increases dramatically in the first decades of forest succession. We tested these two hypotheses using a landscape liana-removal experiment in 30 forest stands that ranged from 10 to 35 yr old in Central Panama. We measured tree growth and biomass accumulation in the stands every year from 2014 to 2017. We found that the effect of liana removal on large trees (≥20-cm diameter) decreased with forest age, supporting the hypothesis that Lianas have the strongest negative effects on trees, and thus biomass uptake and carbon storage, in very young successional forests. Large trees accumulated more biomass in the absence of Lianas in younger forests than in older forests (compared to controls) even after accounting for the effect of canopy completeness and crown illumination, implying that the detrimental effects of Lianas go well beyond resource availability and crown health. There was no significant effect of Lianas on small trees (1-20-cm diameter), likely because Lianas seek light and thus do not deploy their leaves on small trees that are trapped in the forest understory. Our results show that high liana density early in forest succession reduces forest biomass accumulation by negatively impacting large trees, thus decreasing the capacity of young secondary forests to mitigate climate change. Although the negative effects of Lianas on forest biomass diminish as forests age, they do not disappear, and thus Lianas are an important component of tropical forest carbon budgets throughout succession.
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effects of dry season irrigation on leaf physiology and biomass allocation in tropical Lianas and trees
Ecology, 2019Co-Authors: Chris M Smithmartin, Stefan A Schnitzer, Jennifer S Powers, Carolina Lopes Bastos, Omar R LopezAbstract:Lianas are more abundant in seasonal forests than in wetter forests and are thought to perform better than trees when light is abundant and water is limited. We tested the hypothesis that Lianas perform better than trees during seasonal drought using a common garden experiment with 12 taxonomically diverse species (six liana and six tree species) in 12 replicated plots. We irrigated six of the plots during the dry season for four years, while the remaining six control plots received only ambient rainfall. In year 5, we measured stem diameters for all individuals and harvested above‐ and belowground biomass for a subset of individuals to quantify absolute growth and biomass allocation to roots, stems, and leaves, as well as total root length and maximum rooting depth. We also measured rate of photosynthesis, intrinsic water use efficiency (iWUE), pre‐dawn and midday water potential, and a set of functional and hydraulic traits. During the peak of the dry season, Lianas in control plots had 54% higher predawn leaf water potentials (ΨPD), and 45% higher photosynthetic rates than trees in control plots. By contrast, during the peak of the wet season, these physiological differences between Lianas and trees become less pronounced and, in some cases, even disappeared. Trees had higher specific leaf area (SLA) than Lianas; however, no other functional trait differed between growth forms. Trees responded to the irrigation treatment with 15% larger diameters and 119% greater biomass than trees in control plots. Liana growth, however, did not respond to irrigation; liana diameter and biomass were similar in control and irrigation plots, suggesting that Lianas were far less limited by soil moisture than were trees. Contrary to previous hypotheses, Lianas did not have deeper roots than trees; however, Lianas had longer roots per stem diameter than did trees. Our results support the hypothesis that Lianas perform better and experience less physiological stress than trees during seasonal drought, suggesting clear differences between growth forms in response to altered rainfall regimes. Ultimately, better dry‐season performance may explain why liana abundance peaks in seasonal forests compared to trees, which peak in abundance in less seasonal, wetter forests.
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testing ecological theory with Lianas
New Phytologist, 2018Co-Authors: Stefan A SchnitzerAbstract:Contents Summary 366 I. Introduction 366 II. Testing ecological theory: effects of the environment on Lianas 369 III. A unified explanation for liana distribution and the maintenance of liana diversity 370 IV. Testing ecological theory: effects of Lianas on the environment 373 V. Theoretical effects of Lianas on forest diversity 375 VI. Lianas and trophic interactions in forests 375 VII. Unresolved challenges in liana ecology 376 VIII. Conclusions 377 Acknowledgements 377 References 377 SUMMARY: Lianas constitute a diverse polyphyletic plant group that is advancing our understanding of ecological theory. Specifically, Lianas are providing new insights into the mechanisms that control plant distribution and diversity maintenance. For example, there is now evidence that a single, scalable mechanism may explain local, regional, and pan-tropical distribution of Lianas, as well as the maintenance of liana species diversity. The ability to outcompete trees under dry, stressful conditions in seasonal forests provides Lianas a growth advantage that, over time, results in relatively high abundance in seasonal forests and low abundance in aseasonal forests. Lianas may also gain a similar growth advantage following disturbance, thus explaining why liana density and diversity peak following disturbance at the local, forest scale. The study of ecology, however, is more than the effect of the environment on organisms; it also includes the effects of organisms on the environment. Considerable empirical evidence now indicates that Lianas substantially alter their environment by consuming resources, suppressing tree performance, and influencing emergent properties of forests, such as ecosystem functioning, plant and animal diversity, and community composition. These recent studies using Lianas are transcending classical tropical ecology research and are now providing novel insights into fundamental ecological theory.
Jennifer S Powers - One of the best experts on this subject based on the ideXlab platform.
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Lianas maintain insectivorous bird abundance and diversity in a neotropical forest
Ecology, 2020Co-Authors: Stefan A Schnitzer, Jennifer S Powers, Nicole L Michel, Douglas W RobinsonAbstract:The spatial habitat heterogeneity hypothesis posits that habitat complexity increases the abundance and diversity of species. In tropical forests, Lianas add substantial habitat heterogeneity and complexity throughout the vertical forest profile, which may maintain animal abundance and diversity. The effects of Lianas on tropical animal communities, however, remain poorly understood. We propose that Lianas have a positive effect on animals by enhancing habitat complexity. Lianas may have a particularly strong influence on the forest bird community, providing nesting substrate, protection from predators, and nutrition (food). Understory insectivorous birds, which forage for insects that specialize on Lianas, may particularly benefit. Alternatively, it is possible that Lianas have a negative effect on forest birds by increasing predator abundances and providing arboreal predators with travel routes with easy access to bird nests. We tested the spatial habitat heterogeneity hypothesis on bird abundance and diversity by removing Lianas, thus reducing forest complexity, using a large-scale experimental approach in a lowland tropical forest in the Republic of Panama. We found that removing Lianas decreased total bird abundance by 78.4% and diversity by 77.4% after 8 months, and by 40.0% and 51.7%, respectively, after 20 months. Insectivorous bird abundance and diversity 8 months after liana removal were 91.8% and 89.5% lower, respectively, indicating that Lianas positively influence insectivorous birds. The effects of liana removal persisted longer for insectivorous birds than other birds, with 77.3% lower abundance and 76.2% lower diversity after 20 months. Liana removal also altered bird community composition, creating two distinct communities in the control and removal plots, with disproportionate effects on insectivores. Our findings demonstrate that Lianas have a strong positive influence on the bird community, particularly for insectivorous birds in the forest understory. Lianas may maintain bird abundance and diversity by increasing habitat complexity, habitat heterogeneity, and resource availability.
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effects of dry season irrigation on leaf physiology and biomass allocation in tropical Lianas and trees
Ecology, 2019Co-Authors: Chris M Smithmartin, Stefan A Schnitzer, Jennifer S Powers, Carolina Lopes Bastos, Omar R LopezAbstract:Lianas are more abundant in seasonal forests than in wetter forests and are thought to perform better than trees when light is abundant and water is limited. We tested the hypothesis that Lianas perform better than trees during seasonal drought using a common garden experiment with 12 taxonomically diverse species (six liana and six tree species) in 12 replicated plots. We irrigated six of the plots during the dry season for four years, while the remaining six control plots received only ambient rainfall. In year 5, we measured stem diameters for all individuals and harvested above‐ and belowground biomass for a subset of individuals to quantify absolute growth and biomass allocation to roots, stems, and leaves, as well as total root length and maximum rooting depth. We also measured rate of photosynthesis, intrinsic water use efficiency (iWUE), pre‐dawn and midday water potential, and a set of functional and hydraulic traits. During the peak of the dry season, Lianas in control plots had 54% higher predawn leaf water potentials (ΨPD), and 45% higher photosynthetic rates than trees in control plots. By contrast, during the peak of the wet season, these physiological differences between Lianas and trees become less pronounced and, in some cases, even disappeared. Trees had higher specific leaf area (SLA) than Lianas; however, no other functional trait differed between growth forms. Trees responded to the irrigation treatment with 15% larger diameters and 119% greater biomass than trees in control plots. Liana growth, however, did not respond to irrigation; liana diameter and biomass were similar in control and irrigation plots, suggesting that Lianas were far less limited by soil moisture than were trees. Contrary to previous hypotheses, Lianas did not have deeper roots than trees; however, Lianas had longer roots per stem diameter than did trees. Our results support the hypothesis that Lianas perform better and experience less physiological stress than trees during seasonal drought, suggesting clear differences between growth forms in response to altered rainfall regimes. Ultimately, better dry‐season performance may explain why liana abundance peaks in seasonal forests compared to trees, which peak in abundance in less seasonal, wetter forests.
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tropical dry forest trees and Lianas differ in leaf economic spectrum traits but have overlapping water use strategies
Tree Physiology, 2018Co-Authors: Leland K Werden, Bonnie G Waring, Christina M Smithmartin, Jennifer S PowersAbstract:Tree species in tropical dry forests employ a wide range of strategies to cope with seasonal drought, including regulation of hydraulic function. However, it is uncertain if co-occurring Lianas also possess a diversity of strategies. For a taxonomically diverse group of 14 tree and 7 liana species, we measured morphological and hydraulic functional traits during an unusual drought and under non-drought conditions to determine (i) if trees have different water-use strategies than Lianas and (ii) if relationships among these traits can be used to better understand how tree and liana species regulate diurnal leaf water potential (Ψdiurnal). In this Costa Rican tropical dry forest, Lianas and trees had overlapping water-use strategies, but differed in many leaf economic spectrum traits. Specifically, we found that both Lianas and trees employed a diversity of Ψdiurnal regulation strategies, which did not differ statistically. However, Lianas and trees did significantly differ in terms of certain traits including leaf area, specific leaf area, petiole length, wood vessel diameter and xylem vessel density. All liana and tree species we measured fell along a continuum of isohydric (partial) to anisohydric (strict or extreme) Ψdiurnal regulation strategies, and leaf area, petiole length, stomatal conductance and wood vessel diameter correlated with these strategies. These findings contribute to a trait-based understanding of how plants regulate Ψdiurnal under both drought stress and sufficient water availability, and underscore that Lianas and trees employ a similarly wide range of Ψdiurnal regulation strategies, despite having vastly different growth forms.
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Lianas reduce community level canopy tree reproduction in a panamanian forest
Journal of Ecology, 2018Co-Authors: Maria Garcia M Leon, Stefan A Schnitzer, Jennifer S Powers, Laura Martinez Izquierdo, Filipe Niery Arantes MelloAbstract:Lianas are a key component of tropical forests, where they compete intensely with trees, reducing tree recruitment, growth and survival. One of the most important potential outcomes of liana competition is the reduction of tree reproduction; however, no previous study has experimentally determined the effects of Lianas on tree reproduction beyond a single tree species. We used a large-scale liana removal experiment to quantify the effect of Lianas on community-level canopy and understorey tree and palm reproduction. In 2011, we removed Lianas from eight 6,400-m2 plots (eight plots served as controls) and surveyed understorey tree reproduction in 2012, canopy tree and palm reproduction in 2013, and a second census of all plants in 2016. We found that Lianas significantly reduced canopy tree community flowering and fruiting after liana removal. Two years after liana removal, the number of canopy trees with fruits was 173% higher, fruiting individuals had 50% more of their canopy covered by fruits and the number of tree species with fruits was 169% higher than in control plots where Lianas were present. Five years after liana removal, the number of canopy trees with fruits was 150% higher, fruiting individuals had 31% more of their canopy covered by fruits and the number of tree species with fruits was 109% higher than in unmanipulated control plots. Liana removal had only a slight positive effect on palms and on understorey tree flower and fruit production, even though understorey light levels had increased 20% following liana cutting. Synthesis. Our findings provide the first experimental demonstration that competition from Lianas significantly reduces community-level canopy tree reproduction. Reduced reproduction increases canopy tree seed and dispersal limitations, and may interfere with deterministic mechanisms thought to maintain tropical canopy tree species diversity, as well as reduce food availability to many animal species. Because Lianas are increasing in abundance in many neotropical forests, the effects of Lianas on tree reproduction will likely increase, and if the effects of Lianas on tree reproduction vary with tree species identity, Lianas ultimately could have a destabilizing effect on both tree and animal population dynamics.
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contribution of Lianas to plant area index and canopy structure in a panamanian forest
Ecology, 2016Co-Authors: Stefan A Schnitzer, Jennifer S Powers, Elizabeth M Rodriguezronderos, Gil Bohrer, Arturo SanchezazofeifaAbstract:Lianas are an important component of tropical forests, where they reduce tree growth, fecundity, and survival. Competition for light from Lianas may be intense; however, the amount of light that Lianas intercept is poorly understood. We used a large-scale liana-removal experiment to quantify light interception by Lianas in a Panamanian secondary forest. We measured the change in plant area index (PAI) and forest structure before and after cutting Lianas (for four years) in eight 80x80 m plots and eight control plots (16 plots total). We used ground-based LiDAR to measure the 3-dimensional canopy structure before cutting Lianas, and then annually for two years afterwards. Six weeks after cutting Lianas, mean plot PAI was 20% higher in control versus liana removal plots. One year after cutting Lianas, mean plot PAI was ~17% higher in control plots. The differences between treatments diminished significantly two years after liana cutting and, after four years, trees had fully compensated for liana removal. Ground-based LiDAR revealed that Lianas attenuated light in the upper- and middle-forest canopy layers, and not only in the upper-canopy as was previously suspected. Thus, Lianas compete with trees by intercepting light in the upper- and mid-canopy of this forest. This article is protected by copyright. All rights reserved.
Oliver L Phillips - One of the best experts on this subject based on the ideXlab platform.
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liana impacts on carbon cycling storage and sequestration in tropical forests
Biotropica, 2013Co-Authors: Stefan A Schnitzer, Jennifer S Powers, Geertje M F Van Der Heijden, Oliver L PhillipsAbstract:Mature tropical forests sequester large quantities of atmospheric CO2, which they store as plant biomass. These forests are changing however, including an increase in liana abundance and biomass over recent decades in Neotropical forests. We ask here how this increase in Lianas might impact the tropical forest carbon cycle and their capacity for carbon storage and sequestration. Lianas reduce tree growth, survival, and leaf productivity; however, Lianas also invest significantly in leaf production, and the increase in Lianas could conceivably offset liana-induced reductions in tree canopy productivity with no adverse effects to the forest-level canopy productivity. By contrast, Lianas decrease the total ecosystem uptake of carbon by reducing tree biomass productivity. Lianas themselves invest little in woody biomass, and store and sequester only a small proportion of the biomass in tropical forests. As Lianas increase they may effectively displace trees, but the greater liana carbon stocks are unlikely to compensate for liana-induced losses in net carbon sequestration and storage by trees. A potentially important additional consideration is the impact of Lianas on the tree community. By competing more intensely with shade-tolerant, more densely wooded trees than with fast-growing, light-wooded trees, Lianas may shift tree composition toward faster-growing species, which store relatively little carbon, and thereby further reduce the carbon storage capacity of tropical forests. Overall, current evidence indicates that the increase in Lianas will negatively impact the carbon balance of tropical forests, with potentially far-reaching consequences for global atmospheric CO2 levels and associated climate change. Resumen Los bosques tropicales maduros secuestran grandes cantidades de CO2 atmosferico, el cual se almacena en forma de biomasa vegetal. Estos bosques estan cambiando; el numero de Lianas y su biomasa, incluyendo el aumentado en abundancia y biomasa de las Lianas en las ultimas decadas en los bosques neotropicales. Nos preguntamos entonces como el aumento de las Lianas podria afectar el ciclo del carbono de los bosques tropicales y su capacidad para secuestrar y almacenar carbono. Las Lianas reducen el crecimiento de los arboles, disminuyen su supervivencia y productividad foliar; sin embargo, las Lianas tambien invierten de manera significativa en la produccion de hojas, por lo que el aumento de las Lianas podria posiblemente compensar la reduccion inducida por estas en la productividad del dosel arboreo sin efectos adversos en la productividad a nivel del dosel forestal. Por el contrario, las Lianas disminuyen la absorcion total de carbono de los ecosistemas mediante la reduccion en la produccion de biomasa de los arboles. Las Lianas invierten poco en biomasa lenosa y almacenan y secuestran solo una pequena proporcion de biomasa en los bosques tropicales. A medida que las Lianas aumentan en los bosques tropicales, estas podrian desplazar a los arboles y es poco probable que poblaciones mas abundantes de Lianas compensen las perdidas inducidas por si mismas en el secuestro neto de carbono y almacenamiento de los arboles. Una consideracion adicional potencialmente importante es el impacto de las Lianas en la comunidad de arboles. Al competir mas intensamente con arboles que toleran la sombra, y con madera mas densa, respecto a arboles de crecimiento rapido y con madera menos densa, las Lianas pueden modificar la composicion de las especies de arboles favoreciendo a especies de crecimiento mas rapido, que almacenan relativamente menos carbono, y por lo tanto, se reduce aun mas la capacidad de almacenamiento de carbono de los bosques tropicales. En general, las ultimas evidencias indican que el aumento de las Lianas tendra un impacto negativo en el balance de carbono de los bosques tropicales con consecuencias de gran alcance para los niveles globales de CO2 en la atmosfera y el cambio climatico asociado.
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liana infestation impacts tree growth in a lowland tropical moist forest
Biogeosciences, 2009Co-Authors: G M F Van Der Heijden, Oliver L PhillipsAbstract:Abstract. Ecosystem-level estimates of the effect of Lianas on tree growth in mature tropical forests are needed to evaluate the functional impact of Lianas and their potential to affect the ability of tropical forests to sequester carbon, but these are currently lacking. Using data collected on tree growth rates, local growing conditions and liana competition in five permanent sampling plots in Amazonian Peru, we present the first ecosystem-level estimates of the effect of Lianas on above-ground productivity of trees. By first constructing a multi-level linear mixed effect model to predict individual-tree diameter growth model using individual-tree growth conditions, we were able to then estimate stand-level above-ground biomass (AGB) increment in the absence of Lianas. We show that Lianas, mainly by competing above-ground with trees, reduce tree annual above-ground stand-level biomass increment by ~10%, equivalent to 0.51 Mg dry weight ha−1 yr−1 or 0.25 Mg C ha−1 yr−1. AGB increment of Lianas themselves was estimated to be 0.15 Mg dry weight ha−1 yr−1 or 0.07 Mg C ha−1 yr−1, thus only compensating ~29% of the liana-induced reduction in ecosystem AGB increment. Increasing liana pressure on tropical forests will therefore not only tend to reduce their carbon storage capacity, by indirectly promoting tree species with low-density wood, but also their rate of carbon uptake, with potential consequences for the rate of increase in atmospheric carbon dioxide.
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infestation of trees by Lianas in a tropical forest in amazonian peru
Journal of Vegetation Science, 2008Co-Authors: Geertje M F Van Der Heijden, Oliver L Phillips, J R HealeyAbstract:Abstract Question: In Amazonian moist forest, four questions arose: 1. Do tree species differ in their susceptibility to Lianas? 2. What host tree traits (branch-free bole height, growth rate, bark type, leaf length and adult stature) are correlated with the susceptibility of tree species to Lianas infesting the trunk and the crown? 3. To what extent do spatial variables (proximity to liana-infested trees and the light environment of the tree crown) affect the likelihood of liana infestation? 4. Are spatial variables or tree traits relatively more important in influencing the susceptibility of trees to Lianas? We address all questions separately for trunk and crown infestation. Location: Tambopata Nature Reserve, Peru. Methods: We collected information on liana infestation, tree morphological traits, growth, light-environment and position for 3675 trees in seven 1-ha permanent sample plots. We separated trunk from crown infestation and used correlation and logistic regression analyses for tree species and...
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what controls liana success in neotropical forests
Global Ecology and Biogeography, 2008Co-Authors: Geertje M F Van Der Heijden, Oliver L PhillipsAbstract:Aim We seek to determine the factors which control the success of Lianas across macroecological gradients. Lianas have a strong impact on the growth, mortality and biomass of tropical trees, and are reported to be increasing in dominance, so understanding their behaviour is important from the perspectives of both ecological and global change. Location Lowland and montane Neotropical forests. Methods Using 65 standardized samples of Lianas ( ≥ 2.5 cm diameter) from across the Neotropics, we attempted to account for characteristics of both the environment and the forest in explaining macroecological variation in liana success in Neotropical forests, using regression analyses and structural equation modelling. Results We found that both liana density and basal area were unrelated to mean annual precipitation, dry season length or soil variables, except for a weak effect of mean annual precipitation on liana basal area. Structural characteristics of the forest explained more of the variation in liana density and basal area than the physical environment. More disturbed forests generally tended to have a higher liana density. Liana basal area, however, was highest in undisturbed forests. Main conclusions The availability of host trees and their characteristics may be more important than the direct effects of the physical environment in controlling the success of Lianas in Neotropical forests. Changes to the tropical climate in the coming century may not strongly affect Lianas directly, but could have very substantial indirect effects via changes in tree community structure and dynamics.
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large Lianas as hyperdynamic elements of the tropical forest canopy
Ecology, 2005Co-Authors: Oliver L Phillips, Rodolfo Vasquez Martinez, Abel Monteagudo Mendoza, Timothy R Baker, Percy Nunez VargasAbstract:Lianas (woody vines) are an important component of lowland tropical forests. We report large liana and tree inventory and dynamics data from Amazonia over periods of up to 24 years, making this the longest geographically extensive study of liana ecology to date. We use these results to address basic questions about the ecology of large Lianas in mature forests and their interactions with trees. In one intensively studied site we find that large Lianas ($10 cm diameter) represent ,5% of liana stems, but 80% of biomass of well-lit upper canopy Lianas. Across sites, large Lianas and large trees are both most suc- cessful in terms of structural importance in richer soil forests, but large liana success may be controlled more by the availability of large tree supports rather than directly by soil conditions. Long-term annual turnover rates of large Lianas are 5-8%, three times those of trees. Lianas are implicated in large tree mortality: liana-infested large trees are three times more likely to die than liana-free large trees, and large Lianas are involved in the death of at least 30% of tree basal area. Thus large Lianas are a much more dynamic component of Amazon forests than are canopy trees, and they play a much more significant functional role than their structural contribution suggests.
Scott A Mangan - One of the best experts on this subject based on the ideXlab platform.
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unique competitive effects of Lianas and trees in a tropical forest understory
Oecologia, 2015Co-Authors: Stefan A Schnitzer, Scott A Mangan, Alexandra J Wright, Michael F TobinAbstract:Lianas are an important component of tropical forests, contributing up to 25 % of the woody stems and 35 % of woody species diversity. Lianas invest less in structural support but more in leaves compared to trees of similar biomass. These physiological and morphological differences suggest that Lianas may interact with neighboring plants in ways that are different from similarly sized trees. However, the vast majority of past liana competition studies have failed to identify the unique competitive effects of Lianas by controlling for the amount of biomass removed. We assessed liana competition in the forest understory over the course of 3 years by removing liana biomass and an equal amount of tree biomass in 40 plots at 10 sites in a secondary tropical moist forest in central Panama. We found that growth of understory trees and Lianas, as well as planted seedlings, was limited due to competitive effects from both Lianas and trees, though the competitive impacts varied by species, season, and size of neighbors. The removal of trees resulted in greater survival of planted seedlings compared to the removal of Lianas, apparently related to a greater release from competition for light. In contrast, Lianas had a species-specific negative effect on drought-tolerant Dipteryx oleifera seedlings during the dry season, potentially due to competition for water. We conclude that, at local scales, Lianas and trees have unique and differential effects on understory dynamics, with Lianas potentially competing more strongly during the dry season, and trees competing more strongly for light.
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liana abundance diversity and distribution on barro colorado island panama
PLOS ONE, 2012Co-Authors: Stefan A Schnitzer, Scott A Mangan, James W Dalling, Claire A Baldeck, Stephen P Hubbell, Alicia LedoAbstract:Lianas are a key component of tropical forests; however, most surveys are too small to accurately quantify liana community composition, diversity, abundance, and spatial distribution – critical components for measuring the contribution of Lianas to forest processes. In 2007, we tagged, mapped, measured the diameter, and identified all Lianas ≥1 cm rooted in a 50-ha plot on Barro Colorado Island, Panama (BCI). We calculated liana density, basal area, and species richness for both independently rooted Lianas and all rooted liana stems (genets plus clones). We compared spatial aggregation patterns of liana and tree species, and among liana species that varied in the amount of clonal reproduction. We also tested whether liana and tree densities have increased on BCI compared to surveys conducted 30-years earlier. This study represents the most comprehensive spatially contiguous sampling of Lianas ever conducted and, over the 50 ha area, we found 67,447 rooted liana stems comprising 162 species. Rooted Lianas composed nearly 25% of the woody stems (trees and Lianas), 35% of woody species richness, and 3% of woody basal area. Lianas were spatially aggregated within the 50-ha plot and the liana species with the highest proportion of clonal stems more spatially aggregated than the least clonal species, possibly indicating clonal stem recruitment following canopy disturbance. Over the past 30 years, liana density increased by 75% for stems ≥1 cm diameter and nearly 140% for stems ≥5 cm diameter, while tree density on BCI decreased 11.5%; a finding consistent with other neotropical forests. Our data confirm that Lianas contribute substantially to tropical forest stem density and diversity, they have highly clumped distributions that appear to be driven by clonal stem recruitment into treefall gaps, and they are increasing relative to trees, thus indicating that Lianas will play a greater role in the future dynamics of BCI and other neotropical forests.
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resource based habitat associations in a neotropical liana community
Journal of Ecology, 2012Co-Authors: Stefan A Schnitzer, Scott A Mangan, James W Dalling, Claire A Baldeck, Kyle E Harms, Robert John, Elena LoboAbstract:Summary 1. Lianas are a conspicuous element of many tropical forests, accounting for up to 40% of woody stem density and 20% of species richness in seasonal forests. However, Lianas have seldom been surveyed at sufficiently large spatial scales to allow an assessment of the importance of habitat variables in structuring liana communities. 2. We compare the association patterns of 82 liana species and an equivalent sample of tree species on the 50 ha Forest Dynamics Project plot on Barro Colorado Island, Panama, with topographic habitat variables (high and low plateau, slope, swamp and streamside), and thirteen mapped soil chemical variables. In addition, we test for liana species associations with canopy disturbance using a canopy height map of the plot generated using light detection and ranging. 3. For all liana species combined, densities differed among topographic habitat types in the plot, with significantly higher densities on the seasonally drier lower plateau habitat (1044 individuals ha )1 ) than the moister slope habitat (729 individuals ha )1 ). Lianas were also significantly more abundant than expected in areas with low canopy height. 4. The proportion of liana species associated with one or more topographic habitat variables (44%) was significantly lower than that for trees (66%). Similarly, liana species were significantly less frequently associated with PC axes derived from soil chemical variables (21%) than trees (52%). The majority of liana species (63%) were significantly associated with areas of the plot with low canopy height reflecting an affinity for treefall gaps. 5. Synthesis. The habitat associations detected here suggest that liana density is associated primarily with canopy disturbance, and to a lesser extent with topography and soil chemistry. Relative to trees, few liana species were associated with local variation in topography and soil chemistry, suggesting that nutrient availability exerts only weak effects on liana community composition compared to trees. Results from this study support the contention that increases in forest disturbance rates are a driver of recently observed increases in liana abundance and biomass in neotropical forests.
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Lianas have a greater competitive effect than trees of similar biomass on tropical canopy trees
Ecosphere, 2012Co-Authors: Michael F Tobin, Stefan A Schnitzer, Scott A Mangan, Alexandra J WrightAbstract:Lianas (woody vines) reduce growth and survival of host trees in both temperate and tropical forests; however, the relative strength of liana-tree competition in comparison to tree-tree competition remains unexplored. When controlling for biomass, Lianas may have greater competitive effects than trees because the unique morphology of Lianas allows them to reach the forest canopy at relatively small stem diameters and deploy a substantial crown above their host. We tested the hypothesis that Lianas have a greater negative effect on canopy trees than do trees of similar biomass with a liana- and tree sapling-cutting experiment in a seasonal tropical moist forest in Panama. The response of canopy trees to the cutting treatments was characterized as the change in their daily water use by measuring their sap velocity before and after cutting. We compared the responses of canopy trees around which a similar biomass of either Lianas or tree saplings had been cut to control trees with no cutting. Liana cutting increased canopy-tree sap velocity by ∼8% from before to after cutting relative to control trees during the dry season. In contrast, canopy-tree sap velocity did not respond to tree cutting, probably because trees with biomass similar to Lianas were confined to the forest understory. We observed a similar pattern of sap velocity changes during the wet season, but treatment differences were not significant. Our results demonstrate that release from liana competition, but not tree competition, resulted in increased water transport in canopy trees, and suggests that relative to their biomass, Lianas have greater competitive effects on canopy tree performance than do competing trees.
Geertje M F Van Der Heijden - One of the best experts on this subject based on the ideXlab platform.
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Lianas in gaps reduce carbon accumulation in a tropical forest
Ecology, 2014Co-Authors: Stefan A Schnitzer, Geertje M F Van Der Heijden, Joseph Mascaro, Walter P CarsonAbstract:Treefall gaps are the “engines of regeneration” in tropical forests and are loci of high tree recruitment, growth, and carbon accumulation. Gaps, however, are also sites of intense competition between Lianas and trees, whereby Lianas can dramatically reduce tree carbon uptake and accumulation. Because Lianas have relatively low biomass, they may displace far more biomass than they contribute, a hypothesis that has never been tested with the appropriate experiments. We tested this hypothesis with an 8-yr liana removal experiment in central Panama. After 8 years, mean tree biomass accumulation was 180% greater in liana-free treefall gaps compared to control gaps. Lianas themselves contributed only 24% of the tree biomass accumulation they displaced. Scaling to the forest level revealed that Lianas in gaps reduced net forest woody biomass accumulation by 8.9% to nearly 18%. Consequently, Lianas reduce whole-forest carbon uptake despite their relatively low biomass. This is the first study to demonstrate experimentally that plant–plant competition can result in ecosystem-wide losses in forest carbon, and it has critical implications for recently observed increases in liana density and biomass on tropical forest carbon dynamics.
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liana impacts on carbon cycling storage and sequestration in tropical forests
Biotropica, 2013Co-Authors: Stefan A Schnitzer, Jennifer S Powers, Geertje M F Van Der Heijden, Oliver L PhillipsAbstract:Mature tropical forests sequester large quantities of atmospheric CO2, which they store as plant biomass. These forests are changing however, including an increase in liana abundance and biomass over recent decades in Neotropical forests. We ask here how this increase in Lianas might impact the tropical forest carbon cycle and their capacity for carbon storage and sequestration. Lianas reduce tree growth, survival, and leaf productivity; however, Lianas also invest significantly in leaf production, and the increase in Lianas could conceivably offset liana-induced reductions in tree canopy productivity with no adverse effects to the forest-level canopy productivity. By contrast, Lianas decrease the total ecosystem uptake of carbon by reducing tree biomass productivity. Lianas themselves invest little in woody biomass, and store and sequester only a small proportion of the biomass in tropical forests. As Lianas increase they may effectively displace trees, but the greater liana carbon stocks are unlikely to compensate for liana-induced losses in net carbon sequestration and storage by trees. A potentially important additional consideration is the impact of Lianas on the tree community. By competing more intensely with shade-tolerant, more densely wooded trees than with fast-growing, light-wooded trees, Lianas may shift tree composition toward faster-growing species, which store relatively little carbon, and thereby further reduce the carbon storage capacity of tropical forests. Overall, current evidence indicates that the increase in Lianas will negatively impact the carbon balance of tropical forests, with potentially far-reaching consequences for global atmospheric CO2 levels and associated climate change. Resumen Los bosques tropicales maduros secuestran grandes cantidades de CO2 atmosferico, el cual se almacena en forma de biomasa vegetal. Estos bosques estan cambiando; el numero de Lianas y su biomasa, incluyendo el aumentado en abundancia y biomasa de las Lianas en las ultimas decadas en los bosques neotropicales. Nos preguntamos entonces como el aumento de las Lianas podria afectar el ciclo del carbono de los bosques tropicales y su capacidad para secuestrar y almacenar carbono. Las Lianas reducen el crecimiento de los arboles, disminuyen su supervivencia y productividad foliar; sin embargo, las Lianas tambien invierten de manera significativa en la produccion de hojas, por lo que el aumento de las Lianas podria posiblemente compensar la reduccion inducida por estas en la productividad del dosel arboreo sin efectos adversos en la productividad a nivel del dosel forestal. Por el contrario, las Lianas disminuyen la absorcion total de carbono de los ecosistemas mediante la reduccion en la produccion de biomasa de los arboles. Las Lianas invierten poco en biomasa lenosa y almacenan y secuestran solo una pequena proporcion de biomasa en los bosques tropicales. A medida que las Lianas aumentan en los bosques tropicales, estas podrian desplazar a los arboles y es poco probable que poblaciones mas abundantes de Lianas compensen las perdidas inducidas por si mismas en el secuestro neto de carbono y almacenamiento de los arboles. Una consideracion adicional potencialmente importante es el impacto de las Lianas en la comunidad de arboles. Al competir mas intensamente con arboles que toleran la sombra, y con madera mas densa, respecto a arboles de crecimiento rapido y con madera menos densa, las Lianas pueden modificar la composicion de las especies de arboles favoreciendo a especies de crecimiento mas rapido, que almacenan relativamente menos carbono, y por lo tanto, se reduce aun mas la capacidad de almacenamiento de carbono de los bosques tropicales. En general, las ultimas evidencias indican que el aumento de las Lianas tendra un impacto negativo en el balance de carbono de los bosques tropicales con consecuencias de gran alcance para los niveles globales de CO2 en la atmosfera y el cambio climatico asociado.
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infestation of trees by Lianas in a tropical forest in amazonian peru
Journal of Vegetation Science, 2008Co-Authors: Geertje M F Van Der Heijden, Oliver L Phillips, J R HealeyAbstract:Abstract Question: In Amazonian moist forest, four questions arose: 1. Do tree species differ in their susceptibility to Lianas? 2. What host tree traits (branch-free bole height, growth rate, bark type, leaf length and adult stature) are correlated with the susceptibility of tree species to Lianas infesting the trunk and the crown? 3. To what extent do spatial variables (proximity to liana-infested trees and the light environment of the tree crown) affect the likelihood of liana infestation? 4. Are spatial variables or tree traits relatively more important in influencing the susceptibility of trees to Lianas? We address all questions separately for trunk and crown infestation. Location: Tambopata Nature Reserve, Peru. Methods: We collected information on liana infestation, tree morphological traits, growth, light-environment and position for 3675 trees in seven 1-ha permanent sample plots. We separated trunk from crown infestation and used correlation and logistic regression analyses for tree species and...
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what controls liana success in neotropical forests
Global Ecology and Biogeography, 2008Co-Authors: Geertje M F Van Der Heijden, Oliver L PhillipsAbstract:Aim We seek to determine the factors which control the success of Lianas across macroecological gradients. Lianas have a strong impact on the growth, mortality and biomass of tropical trees, and are reported to be increasing in dominance, so understanding their behaviour is important from the perspectives of both ecological and global change. Location Lowland and montane Neotropical forests. Methods Using 65 standardized samples of Lianas ( ≥ 2.5 cm diameter) from across the Neotropics, we attempted to account for characteristics of both the environment and the forest in explaining macroecological variation in liana success in Neotropical forests, using regression analyses and structural equation modelling. Results We found that both liana density and basal area were unrelated to mean annual precipitation, dry season length or soil variables, except for a weak effect of mean annual precipitation on liana basal area. Structural characteristics of the forest explained more of the variation in liana density and basal area than the physical environment. More disturbed forests generally tended to have a higher liana density. Liana basal area, however, was highest in undisturbed forests. Main conclusions The availability of host trees and their characteristics may be more important than the direct effects of the physical environment in controlling the success of Lianas in Neotropical forests. Changes to the tropical climate in the coming century may not strongly affect Lianas directly, but could have very substantial indirect effects via changes in tree community structure and dynamics.