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Gora EM, DeFillipis DM, Schnitzer SA. Patterns and inferred causes of liana mortality in a tropical forest. Proc Biol Sci 2024; 291:20240808. [PMID: 38889791 DOI: 10.1098/rspb.2024.0808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 05/08/2024] [Indexed: 06/20/2024] Open
Abstract
Lianas are major contributors to tropical forest dynamics, yet we know little about their mortality. Using overlapping censuses of the lianas and trees across a 50 ha stand of moist tropical forest, we contrasted community-wide patterns of liana mortality with relatively well-studied patterns of tree mortality to quantify patterns of liana death and identify contributing factors. Liana mortality rates were 172% higher than tree mortality rates, but species-level mortality rates of lianas were similar to trees with 'fast' life-history strategies and both growth forms exhibited similar spatial and size-dependent patterns. The mortality rates of liana saplings (<2.1 cm in diameter), which represent about 50% of liana individuals, decreased with increasing disturbance severity and remained consistently low during post-disturbance stand thinning. In contrast, larger liana individuals and trees of all sizes had elevated mortality rates in response to disturbance and their mortality rates decreased over time since disturbance. Within undisturbed forest patches, liana mortality rates increased with increasing soil fertility in a manner similar to trees. The distinct responses of liana saplings to disturbance appeared to distinguish liana mortality from that of trees, whereas similarities in their patterns of death suggest that there are common drivers of woody plant mortality.
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Affiliation(s)
- Evan M Gora
- Smithsonian Tropical Research Institute, Balboa , Ancón, Panama
- Cary Institute of Ecosystem Studies , Millbrook, NY, USA
| | | | - Stefan A Schnitzer
- Smithsonian Tropical Research Institute, Balboa , Ancón, Panama
- Department of Biological Sciences, Marquette , Milwaukee, WI, USA
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2
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Bin Y, Huang Z, Cao H, Ye W, Lian J. Seed rain composition responds to climate change in a subtropical forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166772. [PMID: 37666333 DOI: 10.1016/j.scitotenv.2023.166772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/26/2023] [Accepted: 08/28/2023] [Indexed: 09/06/2023]
Abstract
Recent climate change has been shown to alter aspects of forest plant demography, such as growth and mortality, but less attention has been focused on how climate change alters the reproduction of plant populations through time. We hypothesized that the plant seed production would respond to climate change, and that the response would differ according to plant life form and functional traits. We tested this hypothesis by examining climate change from 2005 to 2020 and by determining the temporal trends of seed rain and seed production from plants with different life forms (e.g., herbs, vines, trees, palms) and of tree species with different statures as well as leaf, seed and wood traits during 2014-2020. We also tested the correlation between meteorological variables and time series of seed rain using cross correlation analysis. We found increasing wetness (lower vapor pressure deficit) through time but with decreasing minimum relative humidity, which is a pattern consistent with trends seen in many other parts of the world. During the study period, seed production of shrubs and relative contribution of woody vines to total seed rain decreased, while relative contribution of palms to total seed rain and tree species with more conservative leaf traits increased their contribution to total seed rain. Overall, these trends were well explained by the trends of meteorological variables and the responses of these life forms to climate change in previous studies. Additionally, the increasingly conservative leaf traits were also consistent with shifts in traits following recovery from disturbance. Our results suggest that a trait-based approach may help to unveil trends that are not readily apparent by examining seed counts alone. The compositional change found in the seed rain may indicate future shifts in forest species composition and should be incorporated into future studies of forest modelling and projections under climate change.
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Affiliation(s)
- Yue Bin
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, 8 Guangzhou, Guangdong 510650, China
| | - Zhongliang Huang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, 8 Guangzhou, Guangdong 510650, China
| | - Honglin Cao
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, 8 Guangzhou, Guangdong 510650, China
| | - Wanhui Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, 8 Guangzhou, Guangdong 510650, China
| | - Juyu Lian
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, 8 Guangzhou, Guangdong 510650, China.
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3
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Goll DS, Bauters M, Zhang H, Ciais P, Balkanski Y, Wang R, Verbeeck H. Atmospheric phosphorus deposition amplifies carbon sinks in simulations of a tropical forest in Central Africa. THE NEW PHYTOLOGIST 2023; 237:2054-2068. [PMID: 36226674 DOI: 10.1111/nph.18535] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
Spatial redistribution of nutrients by atmospheric transport and deposition could theoretically act as a continental-scale mechanism which counteracts declines in soil fertility caused by nutrient lock-up in accumulating biomass in tropical forests in Central Africa. However, to what extent it affects carbon sinks in forests remains elusive. Here we use a terrestrial biosphere model to quantify the impact of changes in atmospheric nitrogen and phosphorus deposition on plant nutrition and biomass carbon sink at a typical lowland forest site in Central Africa. We find that the increase in nutrient deposition since the 1980s could have contributed to the carbon sink over the past four decades up to an extent which is similar to that from the combined effects of increasing atmospheric carbon dioxide and climate change. Furthermore, we find that the modelled carbon sink responds to changes in phosphorus deposition, but less so to nitrogen deposition. The pronounced response of ecosystem productivity to changes in nutrient deposition illustrates a potential mechanism that could control carbon sinks in Central Africa. Monitoring the quantity and quality of nutrient deposition is needed in this region, given the changes in nutrient deposition due to human land use.
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Affiliation(s)
- Daniel S Goll
- Laboratoire des Sciences du Climat et de l'Environnement, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CNRS, Université de Versailles Saint-Quentin, Université Paris Saclay, Gif-sur-Yvette, 91190, France
| | - Marijn Bauters
- Isotope Bioscience Laboratory-ISOFYS, Ghent University, Ghent, 9000, Belgium
- Department of Environment, Computational and Applied Vegetation Ecology - CAVElab, Ghent University, Ghent, 9000, Belgium
| | - Haicheng Zhang
- Department Geoscience, Environment & Society, Université Libre de Bruxelles, Bruxelles, 1050, Belgium
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CNRS, Université de Versailles Saint-Quentin, Université Paris Saclay, Gif-sur-Yvette, 91190, France
| | - Yves Balkanski
- Laboratoire des Sciences du Climat et de l'Environnement, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CNRS, Université de Versailles Saint-Quentin, Université Paris Saclay, Gif-sur-Yvette, 91190, France
| | - Rong Wang
- Department of Environmental Science and Engineering, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Fudan University, Shanghai, 200438, China
- Integrated Research on Disaster Risk International Center of Excellence on Risk Interconnectivity and Governance on Weather/Climate Extremes Impact and Public Health, Fudan University, Shanghai, 200438, China
- Department of Atmospheric and Oceanic Sciences, Institute of Atmospheric Sciences, Fudan University, Shanghai, 200438, China
- Center for Urban Eco-Planning & Design, Fudan University, Shanghai, 200438, China
- Big Data Institute for Carbon Emission and Environmental Pollution, Fudan University, Shanghai, 200438, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Hans Verbeeck
- Department of Environment, Computational and Applied Vegetation Ecology - CAVElab, Ghent University, Ghent, 9000, Belgium
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Ofosu‐Bamfo B, Addo‐Fordjour P, Belford EJ. Edge disturbance shapes liana diversity and abundance but not liana‐tree interaction network patterns in moist semi‐deciduous forests, Ghana. Ecol Evol 2022; 12:e8585. [PMID: 35371433 PMCID: PMC8859495 DOI: 10.1002/ece3.8585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 01/05/2022] [Accepted: 01/11/2022] [Indexed: 11/10/2022] Open
Abstract
Edge disturbance can drive liana community changes and alter liana‐tree interaction networks, with ramifications for forest functioning. Understanding edge effects on liana community structure and liana‐tree interactions is therefore essential for forest management and conservation. We evaluated the response patterns of liana community structure and liana‐tree interaction structure to forest edge in two moist semi‐deciduous forests in Ghana (Asenanyo and Suhuma Forest Reserves: AFR and SFR, respectively). Liana community structure and liana‐tree interactions were assessed in 24 50 × 50 m randomly located plots in three forest sites (edge, interior and deep‐interior) established at 0–50 m, 200 m and 400 m from edge. Edge effects positively and negatively influenced liana diversity in forest edges of AFR and SFR, respectively. There was a positive influence of edge disturbance on liana abundance in both forests. We observed anti‐nested structure in all the liana‐tree networks in AFR, while no nestedness was observed in the networks in SFR. The networks in both forests were less connected, and thus more modular and specialised than their null models. Many liana and tree species were specialised, with specialisation tending to be symmetrical. The plant species played different roles in relation to modularity. Most of the species acted as peripherals (specialists), with only a few species having structural importance to the networks. The latter species group consisted of connectors (generalists) and hubs (highly connected generalists). Some of the species showed consistency in their roles across the sites, while the roles of other species changed. Generally, liana species co‐occurred randomly on tree species in all the forest sites, except edge site in AFR where lianas showed positive co‐occurrence. Our findings deepen our understanding of the response of liana communities and liana‐tree interactions to forest edge disturbance, which are useful for managing forest edge.
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Affiliation(s)
- Bismark Ofosu‐Bamfo
- Department of Basic and Applied Biology School of Sciences University of Energy and Natural Resources Sunyani Ghana
| | - Patrick Addo‐Fordjour
- Department of Theoretical and Applied Biology Faculty of Biosciences College of Science Kwame Nkrumah University of Science and Technology Kumasi Ghana
| | - Ebenezer J.D. Belford
- Department of Theoretical and Applied Biology Faculty of Biosciences College of Science Kwame Nkrumah University of Science and Technology Kumasi Ghana
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5
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Bin Rahmad Z, Johari MS, Addo-Fordjour P. Local environmental factors shape liana community structure along an elevation gradient in a tropical rainforest. ECOSCIENCE 2022. [DOI: 10.1080/11956860.2021.1916214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Zakaria Bin Rahmad
- School of Biological Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia
| | | | - Patrick Addo-Fordjour
- Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
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6
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Meunier F, Visser MD, Shiklomanov A, Dietze MC, Guzmán Q. JA, Sanchez‐Azofeifa GA, De Deurwaerder HPT, Krishna Moorthy SM, Schnitzer SA, Marvin DC, Longo M, Liu C, Broadbent EN, Almeyda Zambrano AM, Muller‐Landau HC, Detto M, Verbeeck H. Liana optical traits increase tropical forest albedo and reduce ecosystem productivity. GLOBAL CHANGE BIOLOGY 2022; 28:227-244. [PMID: 34651375 PMCID: PMC9298317 DOI: 10.1111/gcb.15928] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/30/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Lianas are a key growth form in tropical forests. Their lack of self-supporting tissues and their vertical position on top of the canopy make them strong competitors of resources. A few pioneer studies have shown that liana optical traits differ on average from those of colocated trees. Those trait discrepancies were hypothesized to be responsible for the competitive advantage of lianas over trees. Yet, in the absence of reliable modelling tools, it is impossible to unravel their impact on the forest energy balance, light competition, and on the liana success in Neotropical forests. To bridge this gap, we performed a meta-analysis of the literature to gather all published liana leaf optical spectra, as well as all canopy spectra measured over different levels of liana infestation. We then used a Bayesian data assimilation framework applied to two radiative transfer models (RTMs) covering the leaf and canopy scales to derive tropical tree and liana trait distributions, which finally informed a full dynamic vegetation model. According to the RTMs inversion, lianas grew thinner, more horizontal leaves with lower pigment concentrations. Those traits made the lianas very efficient at light interception and significantly modified the forest energy balance and its carbon cycle. While forest albedo increased by 14% in the shortwave, light availability was reduced in the understorey (-30% of the PAR radiation) and soil temperature decreased by 0.5°C. Those liana-specific traits were also responsible for a significant reduction of tree (-19%) and ecosystem (-7%) gross primary productivity (GPP) while lianas benefited from them (their GPP increased by +27%). This study provides a novel mechanistic explanation to the increase in liana abundance, new evidence of the impact of lianas on forest functioning, and paves the way for the evaluation of the large-scale impacts of lianas on forest biogeochemical cycles.
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Affiliation(s)
- Félicien Meunier
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
- Department of Earth and EnvironmentBoston UniversityBostonMassachusettsUSA
| | - Marco D. Visser
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNew JerseyUSA
- Institute of Environmental SciencesLeiden UniversityLeidenThe Netherlands
| | | | - Michael C. Dietze
- Department of Earth and EnvironmentBoston UniversityBostonMassachusettsUSA
| | - J. Antonio Guzmán Q.
- Centre for Earth Observation Sciences (CEOS)Earth and Atmospheric Sciences DepartmentUniversity of AlbertaEdmontonAlbertaCanada
| | - G. Arturo Sanchez‐Azofeifa
- Centre for Earth Observation Sciences (CEOS)Earth and Atmospheric Sciences DepartmentUniversity of AlbertaEdmontonAlbertaCanada
- Smithsonian Tropical Research InstituteBalboaPanama
| | | | - Sruthi M. Krishna Moorthy
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
| | - Stefan A. Schnitzer
- Smithsonian Tropical Research InstituteBalboaPanama
- Department of Biological SciencesMarquette UniversityMilwaukeeWisconsinUSA
| | | | - Marcos Longo
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCaliforniaUSA
| | - Chang Liu
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
| | - Eben N. Broadbent
- Spatial Ecology and Conservation (SPEC) Lab, School of Forest, Fisheries, and Geomatics SciencesUniversity of FloridaGainesvilleFloridaUSA
- Spatial Ecology and Conservation (SPEC) Lab, Center for Latin American StudiesUniversity of FloridaGainesvilleFloridaUSA
| | - Angelica M. Almeyda Zambrano
- Spatial Ecology and Conservation (SPEC) Lab, Center for Latin American StudiesUniversity of FloridaGainesvilleFloridaUSA
| | | | - Matteo Detto
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNew JerseyUSA
- Smithsonian Tropical Research InstituteBalboaPanama
| | - Hans Verbeeck
- CAVElab—Computational and Applied Vegetation EcologyDepartment of EnvironmentGhent UniversityGhentBelgium
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7
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Large tree mortality leads to major aboveground biomass decline in a tropical forest reserve. Oecologia 2021; 197:795-806. [PMID: 34613464 DOI: 10.1007/s00442-021-05048-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 09/27/2021] [Indexed: 10/20/2022]
Abstract
Humans are transforming the ecology of the Earth through rapid changes in land use and climate. These changes can affect tropical forest structure, dynamics and diversity. While numerous studies have focused on diversity metrics, other aspects of forest function, such as long-term biomass dynamics, are often less considered. We evaluated plant community structure change (i.e., abundance, diversity, composition, and aboveground biomass) in a 2.25 ha forest dynamics plot located within a ~ 365 ha reserve in southern Costa Rica. We censused, mapped and identified to species all plants ≥ 5 cm diameter at breast height (DBH) in three surveys spanning 2010-2020. While there were no changes in late-successional species diversity, there were marked changes in overall species composition and biomass. Abundance of large (≥ 40 cm DBH) old-growth dense-wooded trees (e.g., Lauraceae, Rosaceae) decreased dramatically (27%), leading to major biomass decline over time, possibly driven by recent and recurrent drought events. Gaps created by large trees were colonized by early-successional species, but these recruits did not make up for the biomass lost. Finally, stem abundance increased by 20%, driven by increasing dominance of Hampea appendiculata. While results suggest this reserve may effectively conserve overall plant diversity, this may mask other key shifts such as large aboveground biomass loss. If this pattern is pervasive across tropical forest reserves, it could hamper efforts to preserve forest structure and ecosystem services (e.g., carbon storage). Monitoring programs could better assess carbon trends in reserves over time simply by tracking large tree dynamics.
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8
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Newbery DM, Zahnd C. Change in liana density over 30 years in a Bornean rain forest supports the escape hypothesis. Ecosphere 2021. [DOI: 10.1002/ecs2.3537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- D. M. Newbery
- Institute of Plant Sciences University of Bern Altenbergrain 21 Bern 3013 Switzerland
| | - C. Zahnd
- Department of Life Sciences Imperial College London Silwood Park Campus Ascot, Berkshire SL5 7PY UK
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9
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Detection of Spatial and Temporal Patterns of Liana Infestation Using Satellite-Derived Imagery. REMOTE SENSING 2021. [DOI: 10.3390/rs13142774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Lianas (woody vines) play a key role in tropical forest dynamics because of their strong influence on tree growth, mortality and regeneration. Assessing liana infestation over large areas is critical to understand the factors that drive their spatial distribution and to monitor change over time. However, it currently remains unclear whether satellite-based imagery can be used to detect liana infestation across closed-canopy forests and therefore if satellite-observed changes in liana infestation can be detected over time and in response to climatic conditions. Here, we aim to determine the efficacy of satellite-based remote sensing for the detection of spatial and temporal patterns of liana infestation across a primary and selectively logged aseasonal forest in Sabah, Borneo. We used predicted liana infestation derived from airborne hyperspectral data to train a neural network classification for prediction across four Sentinel-2 satellite-based images from 2016 to 2019. Our results showed that liana infestation was positively related to an increase in Greenness Index (GI), a simple metric relating to the amount of photosynthetically active green leaves. Furthermore, this relationship was observed in different forest types and during (2016), as well as after (2017–2019), an El Niño-induced drought. Using a neural network classification, we assessed liana infestation over time and showed an increase in the percentage of severely (>75%) liana infested pixels from 12.9% ± 0.63 (95% CI) in 2016 to 17.3% ± 2 in 2019. This implies that reports of increasing liana abundance may be more wide-spread than currently assumed. This is the first study to show that liana infestation can be accurately detected across closed-canopy tropical forests using satellite-based imagery. Furthermore, the detection of liana infestation during both dry and wet years and across forest types suggests this method should be broadly applicable across tropical forests. This work therefore advances our ability to explore the drivers responsible for patterns of liana infestation at multiple spatial and temporal scales and to quantify liana-induced impacts on carbon dynamics in tropical forests globally.
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10
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Schnitzer SA, Estrada-Villegas S, Wright SJ. The response of lianas to 20 yr of nutrient addition in a Panamanian forest. Ecology 2020; 101:e03190. [PMID: 32893876 DOI: 10.1002/ecy.3190] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/28/2020] [Accepted: 08/07/2020] [Indexed: 02/02/2023]
Abstract
Over the past two decades, liana density and basal area have been increasing in many tropical forests, which has profound consequences for forest diversity and functioning. One hypothesis to explain increasing lianas is elevated nutrient deposition in tropical forests resulting from fossil fuels, agricultural fertilizer, and biomass burning. We tested this hypothesis by surveying all lianas ≥1 cm in diameter (n = 3,967) in 32 plots in a fully factorial nitrogen (N), phosphorus (P), and potassium (K) addition experiment in a mature tropical forest in central Panama. We conducted the nutrient-addition experiment from 1998 until present and we first censused lianas in 2013 and then again in 2018. After 20 yr of nutrient addition (1998-2018), liana density, basal area, and rarefied species richness did not differ significantly among any of the nutrient-addition and control treatments. Moreover, nutrient addition in the most recent 5 yr of the experiment did not affect liana relative growth, recruitment, or mortality rates. From 2013 until 2018, liana density, basal area, and species richness increased annually by 1.6%, 1.4%, and 2.4%, respectively. Nutrient addition did not influence these increases. Our findings indicate that nutrient deposition does not explain increasing lianas in this tropical forest. Instead, increases in tree mortality and disturbance, atmospheric carbon dioxide, drought frequency and severity, and hunting pressure may be more likely explanations for the increase in lianas in tropical forests.
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Affiliation(s)
- Stefan A Schnitzer
- Department of Biological Sciences, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin, 53201, USA.,Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama
| | - Sergio Estrada-Villegas
- Department of Biological Sciences, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin, 53201, USA.,Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama
| | - S Joseph Wright
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama
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11
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Bongers F, Ewango CEN, van der Sande MT, Poorter L. Liana species decline in Congo basin contrasts with global patterns. Ecology 2020; 101:e03004. [PMID: 32100291 PMCID: PMC7317384 DOI: 10.1002/ecy.3004] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 06/24/2019] [Accepted: 10/18/2019] [Indexed: 11/11/2022]
Abstract
Lianas, woody climbing plants, are increasing in many tropical forests, with cascading effects such as decreased forest productivity, carbon sequestration, and resilience. Possible causes are increasing forest fragmentation, CO2 fertilization, and drought. Determining the primary changing species and their underlying vital rates help explain the liana trends. We monitored over 17,000 liana stems for 13 yr in 20 ha of old‐growth forest in the Congo Basin, and here we report changes and vital rates for the community and for the 87 most abundant species. The total liana abundance declined from 15,007 lianas in 1994 to 11,090 in 2001 to 9,978 in 2007. Over half (52%) of the evaluated species have significantly declining populations, showing that the community response is not the result of changes in a few dominant species only. Species density change (i.e., the change in number of individuals per hectare) decreased with mortality rate, tended to increase with recruitment rate, but was independent of growth rate. Species change was independent of functional characteristics important for plant responses to fragmentation, CO2, and drought, such as lifetime light requirements, climbing and dispersal mechanism, and leaf size. These results indicate that in Congo lianas do not show the reputed global liana increase, but rather a decline, and that elements of the reputed drivers underlying global liana change do not apply to this DR Congo forest. We suggest warfare in the Congo Basin to have decimated the elephant population, leading to less disturbance, forest closure, and declining liana numbers. Our results imply that, in this tropical forest, local causes (i.e., disturbance) override more global causes of liana change resulting in liana decline, which sharply contrasts with the liana increase observed elsewhere.
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Affiliation(s)
- Frans Bongers
- Forest Ecology and Forest Management Group, Wageningen University & Research, P.O. Box 47, Wageningen, NL-6700 AA, The Netherlands
| | - Corneille E N Ewango
- Forest Ecology and Forest Management Group, Wageningen University & Research, P.O. Box 47, Wageningen, NL-6700 AA, The Netherlands.,Faculty of Renewable Natural Resources Management, University of Kisangani, B.P.O. 2012, Kisangani, DR Congo.,Biosystematics Group, Wageningen University, P.O. Box 67, Wageningen, NL-6700 AP, The Netherlands
| | - Masha T van der Sande
- Forest Ecology and Forest Management Group, Wageningen University & Research, P.O. Box 47, Wageningen, NL-6700 AA, The Netherlands.,Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, USA.,Institute for Biodiversity & Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University & Research, P.O. Box 47, Wageningen, NL-6700 AA, The Netherlands
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