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Yao J, Wang G, Yu R, Su J, A Y, Zhang X, Wang L, Fang Q. Investigating the regional ecological environment stability and its feedback effect on interference using a novel vegetation resilience assessment model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 930:172728. [PMID: 38663614 DOI: 10.1016/j.scitotenv.2024.172728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/22/2024] [Accepted: 04/22/2024] [Indexed: 05/06/2024]
Abstract
Vegetation resilience is critical for understanding the dynamic feedback effect of regional ecological environment stability against interferences. Thus, based on quantify the interferences of climate dryness and vegetation water deficit affecting vegetation growth function, incorporate mechanical Hooke's law to develop a vegetation resilience assessment model by quantitatively expressing vegetation growth function maintenance ability, to reveal the ecological environment stability and its feedback effect on interferences in the study area. The essential discoveries of the study are as follows: (1) with the increase of precipitation and the improvement of afforestation on soil erosion, the interferences intensity of climate dryness and vegetation water deficit in the ecological environment decreased by 5.88 % and 4.92 % respectively, the regional vegetation growth function loss was improved, especially in the southern region; (2) the decrease of vegetation growth function loss promoted the vegetation resilience level fluctuated from class II to class IV, with the average annual vegetation resilience increased by 7.02 %, reflecting that the regional ecological environment stability increased from difficult to rapid recovery after disturbance, and the benefit was especially noticeable in the eastern and southern forested areas; (3) the contribution rates of climate dryness and vegetation water deficit to the variation of vegetation resilience caused by vegetation restoration were -1.38 % and 4.73 %, respectively, and the prominent positive feedback effect of increasing vegetation resilience with decreasing vegetation water deficit degree in forest restoration area, indicating that the vegetation water deficit greatly impacts ecological environment stability in the study area, and forest restoration constantly improves regional ecological environment stability more than grassland restoration. This research has crucial guiding implications for supporting the sustainable development of regional ecological environments.
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Affiliation(s)
- Jiping Yao
- Inner Mongolia Key Laboratory of River and Lake Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China; Key Laboratory of Mongolian Plateau Ecology and Resource Utilization, Ministry of Education, Hohhot 010021, China
| | - Guoqiang Wang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China; Center for Geodata and Analysis, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
| | - Ruihong Yu
- Inner Mongolia Key Laboratory of River and Lake Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China; Key Laboratory of Mongolian Plateau Ecology and Resource Utilization, Ministry of Education, Hohhot 010021, China
| | - Jie Su
- Basin Research Center for Water Pollution Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
| | - Yinglan A
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China; Center for Geodata and Analysis, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
| | - Xiaojing Zhang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China
| | - Libo Wang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China
| | - Qingqing Fang
- School of Water Conservancy and Hydropower Engineering, North China Electric Power University, Beijing 102206, China
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Wuyts B, Sieber J. Emergent structure and dynamics of tropical forest-grassland landscapes. Proc Natl Acad Sci U S A 2023; 120:e2211853120. [PMID: 37903268 PMCID: PMC10636392 DOI: 10.1073/pnas.2211853120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/06/2023] [Indexed: 11/01/2023] Open
Abstract
Previous work indicates that tropical forest can exist as an alternative stable state to savanna. Therefore, perturbation by climate change or human impact may lead to crossing of a tipping point beyond which there is rapid forest dieback that is not easily reversed. A hypothesized mechanism for such bistability is feedback between fire and vegetation, where fire spreads as a contagion process on grass patches. Theoretical models have largely implemented this mechanism implicitly, by assuming a threshold dependence of fire spread on flammable vegetation. Here, we show how the nonlinear dynamics and bistability emerge spontaneously, without assuming equations or thresholds for fire spread. We find that the forest geometry causes the nonlinearity that induces bistability. We demonstrate this in three steps. First, we model forest and fire as interacting contagion processes on grass patches, showing that spatial structure emerges due to two counteracting effects on the forest perimeter: forest expansion by dispersal and forest erosion by fires originating in adjacent grassland. Then, we derive a landscape-scale balance equation in which these two effects link forest geometry and dynamics: Forest expands proportionally to its perimeter, while it shrinks proportionally to its perimeter weighted by adjacent grassland area. Finally, we show that these perimeter quantities introduce nonlinearity in our balance equation and lead to bistability. Relying on the link between structure and dynamics, we propose a forest resilience indicator that could be used for targeted conservation or restoration.
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Affiliation(s)
- Bert Wuyts
- Centre for Systems, Dynamics and Control, Department of Mathematics and Statistics, University of Exeter, EX4 4QF, United Kingdom
| | - Jan Sieber
- Centre for Systems, Dynamics and Control, Department of Mathematics and Statistics, University of Exeter, EX4 4QF, United Kingdom
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3
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The emergence of scale-free fires in Australia. iScience 2023; 26:106181. [PMID: 36895645 PMCID: PMC9988665 DOI: 10.1016/j.isci.2023.106181] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/15/2022] [Accepted: 02/07/2023] [Indexed: 02/16/2023] Open
Abstract
Between 2019 and 2020, during the country's hottest and driest year on record, Australia experienced a dramatic bushfire season, with catastrophic ecological and environmental consequences. Several studies highlighted how such abrupt changes in fire regimes may have been in large part a consequence of climate change and other anthropogenic transformations. Here, we analyze the monthly evolution of the burned area in Australia from 2000 to 2020, obtained via satellite imaging through the MODIS platform. We find that the 2019-2020 peak is associated with signatures typically found near critical points. We introduce a modeling framework based on forest-fire models to study the properties of these emergent fire outbreaks, showing that the behavior observed during the 2019-2020 fire season matches the one of a percolation transition, where system-size outbreaks appear. Our model also highlights the existence of an absorbing phase transition that might be eventually crossed, after which the vegetation cannot recover.
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He S, Xiong K, Song S, Chi Y, Fang J, He C. Research Progress of Grassland Ecosystem Structure and Stability and Inspiration for Improving Its Service Capacity in the Karst Desertification Control. PLANTS (BASEL, SWITZERLAND) 2023; 12:770. [PMID: 36840118 PMCID: PMC9959505 DOI: 10.3390/plants12040770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/04/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
The structure and stability of grassland ecosystems have a significant impact on biodiversity, material cycling and productivity for ecosystem services. However, the issue of the structure and stability of grassland ecosystems has not been systematically reviewed. Based on the Web of Science (WOS) and China National Knowledge Infrastructure (CNKI) databases, we used the systematic-review method and screened 133 papers to describe and analyze the frontiers of research into the structure and stability of grassland ecosystems. The research results showed that: (1) The number of articles about the structure and stability of grassland ecosystems is gradually increasing, and the research themes are becoming increasingly diverse. (2) There is a high degree of consistency between the study area and the spatial distribution of grassland. (3) Based on the changes in ecosystem patterns and their interrelationships with ecosystem processes, we reviewed the research progress and landmark results on the structure, stability, structure-stability relationship and their influencing factors of grassland ecosystems; among them, the study of structure is the main research focus (51.12%), followed by the study of the influencing factors of structure and stability (37.57%). (4) Key scientific questions on structural optimization, stability enhancement and harmonizing the relationship between structure and stability are explored. (5) Based on the background of karst desertification control (KDC) and its geographical characteristics, three insights are proposed to optimize the spatial allocation, enhance the stability of grassland for rocky desertification control and coordinate the regulation mechanism of grassland structure and stability. This study provided some references for grassland managers and relevant policy makers to optimize the structure and enhance the stability of grassland ecosystems. It also provided important insights to enhance the service capacity of grassland ecosystems in KDC.
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Affiliation(s)
- Shuyu He
- School of Karst Science, Guizhou Normal University, Guiyang 550001, China
- State Engineering Technology Institute for Karst Desertification Control of China, 116 Baoshan North Road, Guiyang 550001, China
| | - Kangning Xiong
- School of Karst Science, Guizhou Normal University, Guiyang 550001, China
- State Engineering Technology Institute for Karst Desertification Control of China, 116 Baoshan North Road, Guiyang 550001, China
| | - Shuzhen Song
- School of Karst Science, Guizhou Normal University, Guiyang 550001, China
- State Engineering Technology Institute for Karst Desertification Control of China, 116 Baoshan North Road, Guiyang 550001, China
| | - Yongkuan Chi
- School of Karst Science, Guizhou Normal University, Guiyang 550001, China
- State Engineering Technology Institute for Karst Desertification Control of China, 116 Baoshan North Road, Guiyang 550001, China
| | - Jinzhong Fang
- School of Karst Science, Guizhou Normal University, Guiyang 550001, China
- State Engineering Technology Institute for Karst Desertification Control of China, 116 Baoshan North Road, Guiyang 550001, China
| | - Chen He
- School of Karst Science, Guizhou Normal University, Guiyang 550001, China
- State Engineering Technology Institute for Karst Desertification Control of China, 116 Baoshan North Road, Guiyang 550001, China
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Carvalho LZG, Massi KG, Coutinho MP, Magalhães VD. Fire effects on Atlantic Forest sites from a composition, structure and functional perspective. BRAZ J BIOL 2023; 82:e268185. [PMID: 36629547 DOI: 10.1590/1519-6984.268185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/13/2022] [Indexed: 01/11/2023] Open
Abstract
Recently, some portions of the Atlantic Forest biome have been suffering an increase in forest fires, possibly changing its vegetation cover, composition, structure and functioning. Understanding these changes is critical to evaluate the present and future response of tropical forests to fire. Thus, the purpose of our study was to evaluate how diversity, structure and functioning of tree communities differed between burned and unburned sites. Two unburned and two burned forest patches were selected for floristic and phytosociological surveys. Then, we calculated species richness, Shannon diversity index, tree density and basal area, Importance Value Index for trees in each site and we assessed community weighted mean of six functional traits (maximum tree height, wood density, leaf length, leaf deciduousness, shade tolerance and dispersal mode). Diversity, species richness, tree density and basal area were similar between sites. We found changes in floristic composition, but did not verified variations in functional traits. Results indicate that recovery may be fast and that pioneer and early secondary species are occupying post burned sites (nine years old). One-time anthropogenic, superficial and low intensity fires might disrupt advanced stages of succession and start again the dynamics of species substitution.
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Affiliation(s)
- L Z G Carvalho
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Centro Nacional de Monitoramento e Alertas de Desastres Naturais - CEMADEN, Programa de Pós-graduação em Desastres Naturais, São José dos Campos, SP, Brasil
| | - K G Massi
- Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Centro Nacional de Monitoramento e Alertas de Desastres Naturais - CEMADEN, Programa de Pós-graduação em Desastres Naturais, São José dos Campos, SP, Brasil.,Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Departamento de Engenharia Ambiental, Instituto de Ciência e Tecnologia, São José dos Campos, SP, Brasil
| | - M P Coutinho
- Centro Paula Souza, Faculdade de Tecnologia - FATEC, Jacareí, SP, Brasil
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Erdős L, Török P, Veldman JW, Bátori Z, Bede‐Fazekas Á, Magnes M, Kröel‐Dulay G, Tölgyesi C. How climate, topography, soils, herbivores, and fire control forest-grassland coexistence in the Eurasian forest-steppe. Biol Rev Camb Philos Soc 2022; 97:2195-2208. [PMID: 35942892 PMCID: PMC9804691 DOI: 10.1111/brv.12889] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 01/09/2023]
Abstract
Recent advances in ecology and biogeography demonstrate the importance of fire and large herbivores - and challenge the primacy of climate - to our understanding of the distribution, stability, and antiquity of forests and grasslands. Among grassland ecologists, particularly those working in savannas of the seasonally dry tropics, an emerging fire-herbivore paradigm is generally accepted to explain grass dominance in climates and on soils that would otherwise permit development of closed-canopy forests. By contrast, adherents of the climate-soil paradigm, particularly foresters working in the humid tropics or temperate latitudes, tend to view fire and herbivores as disturbances, often human-caused, which damage forests and reset succession. Towards integration of these two paradigms, we developed a series of conceptual models to explain the existence of an extensive temperate forest-grassland mosaic that occurs within a 4.7 million km2 belt spanning from central Europe through eastern Asia. The Eurasian forest-steppe is reminiscent of many regions globally where forests and grasslands occur side-by-side with stark boundaries. Our conceptual models illustrate that if mean climate was the only factor, forests should dominate in humid continental regions and grasslands should prevail in semi-arid regions, but that extensive mosaics would not occur. By contrast, conceptual models that also integrate climate variability, soils, topography, herbivores, and fire depict how these factors collectively expand suitable conditions for forests and grasslands, such that grasslands may occur in more humid regions and forests in more arid regions than predicted by mean climate alone. Furthermore, boundaries between forests and grasslands are reinforced by vegetation-fire, vegetation-herbivore, and vegetation-microclimate feedbacks, which limit tree establishment in grasslands and promote tree survival in forests. Such feedbacks suggest that forests and grasslands of the Eurasian forest-steppe are governed by ecological dynamics that are similar to those hypothesised to maintain boundaries between tropical forests and savannas. Unfortunately, the grasslands of the Eurasian forest-steppe are sometimes misinterpreted as deforested or otherwise degraded vegetation. In fact, the grasslands of this region provide valuable ecosystem services, support a high diversity of plants and animals, and offer critical habitat for endangered large herbivores. We suggest that a better understanding of the fundamental ecological controls that permit forest-grassland coexistence could help us prioritise conservation and restoration of the Eurasian forest-steppe for biodiversity, climate adaptation, and pastoral livelihoods. Currently, these goals are being undermined by tree-planting campaigns that view the open grasslands as opportunities for afforestation. Improved understanding of the interactive roles of climate variability, soils, topography, fire, and herbivores will help scientists and policymakers recognise the antiquity of the grasslands of the Eurasian forest-steppe.
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Affiliation(s)
- László Erdős
- Institute of Ecology and BotanyCentre for Ecological ResearchAlkotmány utca 2‐42163VácrátótHungary,MTA‐DE Lendület Functional and Restoration Ecology Research GroupEgyetem tér 14032DebrecenHungary
| | - Péter Török
- MTA‐DE Lendület Functional and Restoration Ecology Research GroupEgyetem tér 14032DebrecenHungary,Department of EcologyUniversity of DebrecenEgyetem tér 14032DebrecenHungary,Botanical Garden – Center for Biological Diversity Conservation in PowsinPolish Academy of SciencesPrawdziwka street 202‐973WarszawaPoland
| | - Joseph W. Veldman
- Department of Ecology and Conservation BiologyTexas A&M UniversityCollege StationTX77843‐2258USA
| | - Zoltán Bátori
- Department of EcologyUniversity of SzegedKözép fasor 526726SzegedHungary
| | - Ákos Bede‐Fazekas
- Institute of Ecology and BotanyCentre for Ecological ResearchAlkotmány utca 2‐42163VácrátótHungary,Department of Environmental and Landscape GeographyEötvös Loránd UniversityPázmány Péter sétány 1/C1117BudapestHungary
| | - Martin Magnes
- Institute of BiologyUniversity of GrazHolteigasse 68010GrazAustria
| | - György Kröel‐Dulay
- Institute of Ecology and BotanyCentre for Ecological ResearchAlkotmány utca 2‐42163VácrátótHungary
| | - Csaba Tölgyesi
- MTA‐SZTE ‘Momentum’ Applied Ecology Research GroupKözép fasor 526726SzegedHungary
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7
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Flores BM, Staal A. Feedback in tropical forests of the Anthropocene. GLOBAL CHANGE BIOLOGY 2022; 28:5041-5061. [PMID: 35770837 PMCID: PMC9542052 DOI: 10.1111/gcb.16293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 04/06/2022] [Accepted: 05/31/2022] [Indexed: 05/27/2023]
Abstract
Tropical forests are complex systems containing myriad interactions and feedbacks with their biotic and abiotic environments, but as the world changes fast, the future of these ecosystems becomes increasingly uncertain. In particular, global stressors may unbalance the feedbacks that stabilize tropical forests, allowing other feedbacks to propel undesired changes in the whole ecosystem. Here, we review the scientific literature across various fields, compiling known interactions of tropical forests with their environment, including the global climate, rainfall, aerosols, fire, soils, fauna, and human activities. We identify 170 individual interactions among 32 elements that we present as a global tropical forest network, including countless feedback loops that may emerge from different combinations of interactions. We illustrate our findings with three cases involving urgent sustainability issues: (1) wildfires in wetlands of South America; (2) forest encroachment in African savanna landscapes; and (3) synergistic threats to the peatland forests of Borneo. Our findings reveal an unexplored world of feedbacks that shape the dynamics of tropical forests. The interactions and feedbacks identified here can guide future qualitative and quantitative research on the complexities of tropical forests, allowing societies to manage the nonlinear responses of these ecosystems in the Anthropocene.
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Affiliation(s)
- Bernardo M. Flores
- Graduate Program in EcologyFederal University of Santa CatarinaFlorianopolisBrazil
| | - Arie Staal
- Copernicus Institute of Sustainable DevelopmentUtrecht UniversityUtrechtThe Netherlands
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Tölgyesi C, Vadász C, Kun R, Csathó AI, Bátori Z, Hábenczyus A, Erdős L, Török P. Post-restoration grassland management overrides the effects of restoration methods in propagule-rich landscapes. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e02463. [PMID: 34614249 PMCID: PMC9285412 DOI: 10.1002/eap.2463] [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: 02/01/2021] [Revised: 05/03/2021] [Accepted: 05/24/2021] [Indexed: 06/13/2023]
Abstract
Grassland restoration is gaining momentum worldwide to tackle the loss of biodiversity and associated ecosystem services. Restoration methods and their effects on ecological community reassembly have been extensively studied across various grassland types, while the importance of post-restoration management has so far received less attention. Grassland management is an important surrogate for natural disturbances, with which most ancient grasslands have coevolved. Thus, without the reintroduction of management-related disturbance, restoration targets are unlikely to be achieved in restored grasslands. In this study, we aimed to explore how 20 yr of management by mowing once a year or light cattle grazing affects restoration success in Palearctic meadow-steppe grasslands restored by either sowing native grasses (sown sites), applying Medicago sativa as a nurse plant (Medicago sites), or allowing spontaneous succession (spontaneous sites). We found that, following mowing, sown sites maintained long-lasting establishment limitation, while Medicago sites experienced a delay in succession. These limitations resulted in low total and target species richness, low functional redundancy, and distinct species and functional composition compared to reference data from ancient grasslands. Spontaneous sites that were mowed reached a more advanced successional stage, although they did not reach reference levels regarding most vegetation descriptors. Sown and Medicago sites that were grazed had higher total and target species richness than those that were mowed, and showed restoration success similar to that of spontaneous sites, on which grazing had only moderate further positive effects. Grazed sites, irrespective of the restoration method, were uniformly species rich, functionally diverse, and functionally redundant, and thus became important biodiverse habitats with considerable resilience. We conclude that an optimally chosen post-restoration management may have an impact on long-term community reassembly comparable to the choice of restoration method. Restoration planners may, therefore, need to put more emphasis on future management than on the initial restoration method. However, our findings also imply that if local constraints, such as potentially high invasive propagule pressure, necessitate the application of restoration methods that could also hinder the establishment of target species, the long-term recovery of the grassland can still be ensured by wisely chosen post-restoration management.
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Affiliation(s)
- Csaba Tölgyesi
- Department of EcologyUniversity of SzegedSzeged6726Hungary
- MTA‐DE Lendület Functional and Restoration Ecology Research GroupUniversity of DebrecenDebrecen4032Hungary
| | - Csaba Vadász
- Kiskunság National Park DirectorateLiszt Ferenc utca 19Kecskemét6000Hungary
| | - Róbert Kun
- Institute of Nature Conservation and Landscape ManagementSzent István UniversityGödöllő2103Hungary
| | | | - Zoltán Bátori
- Department of EcologyUniversity of SzegedSzeged6726Hungary
| | | | - László Erdős
- MTA‐DE Lendület Functional and Restoration Ecology Research GroupUniversity of DebrecenDebrecen4032Hungary
- Centre for Ecological ResearchInstitute of Ecology and BotanyVácrátót2163Hungary
| | - Péter Török
- MTA‐DE Lendület Functional and Restoration Ecology Research GroupUniversity of DebrecenDebrecen4032Hungary
- Polish Academy of SciencesBotanical Garden ‐ Center for Biological Diversity Conservation in PowsinPrawdziwka 2Warszawa02‐973Poland
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9
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Albrich K, Rammer W, Turner MG, Ratajczak Z, Braziunas KH, Hansen WD, Seidl R. Simulating forest resilience: A review. GLOBAL ECOLOGY AND BIOGEOGRAPHY : A JOURNAL OF MACROECOLOGY 2020; 29:2082-2096. [PMID: 33380902 PMCID: PMC7756463 DOI: 10.1111/geb.13197] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/18/2020] [Accepted: 09/10/2020] [Indexed: 06/02/2023]
Abstract
AIM Simulation models are important tools for quantifying the resilience (i.e., persistence under changed environmental conditions) of forest ecosystems to global change. We synthesized the modelling literature on forest resilience, summarizing common models and applications in resilience research, and scrutinizing the implementation of important resilience mechanisms in these models. Models applied to assess resilience are highly diverse, and our goal was to assess how well they account for important resilience mechanisms identified in experimental and empirical research. LOCATION Global. TIME PERIOD 1994 to 2019. MAJOR TAXA STUDIED Trees. METHODS We reviewed the forest resilience literature using online databases, selecting 119 simulation modelling studies for further analysis. We identified a set of resilience mechanisms from the general resilience literature and analysed models for their representation of these mechanisms. Analyses were grouped by investigated drivers (resilience to what) and responses (resilience of what), as well as by the type of model being used. RESULTS Models used to study forest resilience varied widely, from analytical approaches to complex landscape simulators. The most commonly addressed questions were associated with resilience of forest cover to fire. Important resilience mechanisms pertaining to regeneration, soil processes, and disturbance legacies were explicitly simulated in only 34 to 46% of the model applications. MAIN CONCLUSIONS We found a large gap between processes identified as underpinning forest resilience in the theoretical and empirical literature, and those represented in models used to assess forest resilience. Contemporary forest models developed for other goals may be poorly suited for studying forest resilience during an era of accelerating change. Our results highlight the need for a new wave of model development to enhance understanding of and management for resilient forests.
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Affiliation(s)
- Katharina Albrich
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaWienAustria
- Ecosystem Dynamics and Forest Management GroupTechnical University of MunichFreisingGermany
| | - Werner Rammer
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaWienAustria
- Ecosystem Dynamics and Forest Management GroupTechnical University of MunichFreisingGermany
| | - Monica G. Turner
- Department of Integrative BiologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Zak Ratajczak
- Department of Integrative BiologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Kristin H. Braziunas
- Department of Integrative BiologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | | | - Rupert Seidl
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaWienAustria
- Ecosystem Dynamics and Forest Management GroupTechnical University of MunichFreisingGermany
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10
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Abstract
Tropical forests modify the conditions they depend on through feedbacks at different spatial scales. These feedbacks shape the hysteresis (history-dependence) of tropical forests, thus controlling their resilience to deforestation and response to climate change. Here, we determine the emergent hysteresis from local-scale tipping points and regional-scale forest-rainfall feedbacks across the tropics under the recent climate and a severe climate-change scenario. By integrating remote sensing, a global hydrological model, and detailed atmospheric moisture tracking simulations, we find that forest-rainfall feedback expands the geographic range of possible forest distributions, especially in the Amazon. The Amazon forest could partially recover from complete deforestation, but may lose that resilience later this century. The Congo forest currently lacks resilience, but is predicted to gain it under climate change, whereas forests in Australasia are resilient under both current and future climates. Our results show how tropical forests shape their own distributions and create the climatic conditions that enable them.
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11
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Lasslop G, Hantson S, Harrison SP, Bachelet D, Burton C, Forkel M, Forrest M, Li F, Melton JR, Yue C, Archibald S, Scheiter S, Arneth A, Hickler T, Sitch S. Global ecosystems and fire: Multi-model assessment of fire-induced tree-cover and carbon storage reduction. GLOBAL CHANGE BIOLOGY 2020; 26:5027-5041. [PMID: 32407565 DOI: 10.1111/gcb.15160] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/28/2020] [Indexed: 05/09/2023]
Abstract
In this study, we use simulations from seven global vegetation models to provide the first multi-model estimate of fire impacts on global tree cover and the carbon cycle under current climate and anthropogenic land use conditions, averaged for the years 2001-2012. Fire globally reduces the tree covered area and vegetation carbon storage by 10%. Regionally, the effects are much stronger, up to 20% for certain latitudinal bands, and 17% in savanna regions. Global fire effects on total carbon storage and carbon turnover times are lower with the effect on gross primary productivity (GPP) close to 0. We find the strongest impacts of fire in savanna regions. Climatic conditions in regions with the highest burned area differ from regions with highest absolute fire impact, which are characterized by higher precipitation. Our estimates of fire-induced vegetation change are lower than previous studies. We attribute these differences to different definitions of vegetation change and effects of anthropogenic land use, which were not considered in previous studies and decreases the impact of fire on tree cover. Accounting for fires significantly improves the spatial patterns of simulated tree cover, which demonstrates the need to represent fire in dynamic vegetation models. Based upon comparisons between models and observations, process understanding and representation in models, we assess a higher confidence in the fire impact on tree cover and vegetation carbon compared to GPP, total carbon storage and turnover times. We have higher confidence in the spatial patterns compared to the global totals of the simulated fire impact. As we used an ensemble of state-of-the-art fire models, including effects of land use and the ensemble median or mean compares better to observational datasets than any individual model, we consider the here presented results to be the current best estimate of global fire effects on ecosystems.
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Affiliation(s)
- Gitta Lasslop
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | - Stijn Hantson
- Department of Earth System Sciences, University of California Irvine, Irvine, CA, USA
| | - Sandy P Harrison
- School of Archaeology, Geography and Environmental Sciences (SAGES), University of Reading, Reading, UK
| | | | | | - Matthias Forkel
- Environmental Remote Sensing Group, Institute of Photogrammetry and Remote Sensing, Technische Universität Dresden, Dresden, Germany
| | - Matthew Forrest
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | - Fang Li
- International Center for Climate and Environmental Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Joe R Melton
- Climate Research Division, Environment Canada, Victoria, BC, Canada
| | - Chao Yue
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Sally Archibald
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Simon Scheiter
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | - Almut Arneth
- Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Atmospheric Environmental Research, Garmisch-Partenkirchen, Germany
| | - Thomas Hickler
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
- Department of Physical Geography, Goethe University, Frankfurt am Main, Germany
| | - Stephen Sitch
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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12
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Detecting Vegetation Recovery after Fire in A Fire-Frequented Habitat Using Normalized Difference Vegetation Index (NDVI). FORESTS 2020. [DOI: 10.3390/f11070749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Research Highlights: Fire-frequented savannas are dominated by plant species that regrow quickly following fires that mainly burn through the understory. To detect post-fire vegetation recovery in these ecosystems, particularly during warm, rainy seasons, data are needed on a small, temporal scale. In the past, the measurement of vegetation regrowth in fire-frequented systems has been labor-intensive, but with the availability of daily satellite imagery, it should be possible to easily determine vegetation recovery on a small timescale using Normalized Difference Vegetation Index (NDVI) in ecosystems with a sparse overstory. Background and Objectives: We explore whether it is possible to use NDVI calculated from satellite imagery to detect time-to-vegetation recovery. Additionally, we determine the time-to-vegetation recovery after fires in different seasons. This represents one of very few studies that have used satellite imagery to examine vegetation recovery after fire in southeastern U.S.A. pine savannas. We test the efficacy of using this method by examining whether there are detectable differences between time-to-vegetation recovery in subtropical savannas burned during different seasons. Materials and Methods: NDVI was calculated from satellite imagery approximately monthly over two years in a subtropical savanna with units burned during dry, dormant and wet, growing seasons. Results: Despite the availability of daily satellite images, we were unable to precisely determine when vegetation recovered, because clouds frequently obscured our range of interest. We found that, in general, vegetation recovered in less time after fire during the wet, growing, as compared to dry, dormant, season, albeit there were some discrepancies in our results. Although these general patterns were clear, variation in fire heterogeneity and canopy type and cover skewed NDVI in some units. Conclusions: Although there are some challenges to using satellite-derived NDVI, the availability of satellite imagery continues to improve on both temporal and spatial scales, which should allow us to continue finding new and efficient ways to monitor and model forests in the future.
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Albrich K, Rammer W, Seidl R. Climate change causes critical transitions and irreversible alterations of mountain forests. GLOBAL CHANGE BIOLOGY 2020; 26:4013-4027. [PMID: 32301569 PMCID: PMC7317840 DOI: 10.1111/gcb.15118] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 03/18/2020] [Accepted: 03/30/2020] [Indexed: 05/12/2023]
Abstract
Mountain forests are at particular risk of climate change impacts due to their temperature limitation and high exposure to warming. At the same time, their complex topography may help to buffer the effects of climate change and create climate refugia. Whether climate change can lead to critical transitions of mountain forest ecosystems and whether such transitions are reversible remain incompletely understood. We investigated the resilience of forest composition and size structure to climate change, focusing on a mountain forest landscape in the Eastern Alps. Using the individual-based forest landscape model iLand, we simulated ecosystem responses to a wide range of climatic changes (up to a 6°C increase in mean annual temperature and a 30% reduction in mean annual precipitation), testing for tipping points in vegetation size structure and composition under different topography scenarios. We found that at warming levels above +2°C a threshold was crossed, with the system tipping into an alternative state. The system shifted from a conifer-dominated landscape characterized by large trees to a landscape dominated by smaller, predominantly broadleaved trees. Topographic complexity moderated climate change impacts, smoothing and delaying the transitions between alternative vegetation states. We subsequently reversed the simulated climate forcing to assess the ability of the landscape to recover from climate change impacts. The forest landscape showed hysteresis, particularly in scenarios with lower precipitation. At the same mean annual temperature, equilibrium vegetation size structure and species composition differed between warming and cooling trajectories. Here we show that even moderate warming corresponding to current policy targets could result in critical transitions of forest ecosystems and highlight the importance of topographic complexity as a buffering agent. Furthermore, our results show that overshooting ambitious climate mitigation targets could be dangerous, as ecological impacts can be irreversible at millennial time scales once a tipping point has been crossed.
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Affiliation(s)
- Katharina Albrich
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaViennaAustria
- Ecosystem Dynamics and Forest Management GroupTechnical University of MunichFreisingGermany
| | - Werner Rammer
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaViennaAustria
- Ecosystem Dynamics and Forest Management GroupTechnical University of MunichFreisingGermany
| | - Rupert Seidl
- Institute of SilvicultureUniversity of Natural Resources and Life Sciences (BOKU) ViennaViennaAustria
- Ecosystem Dynamics and Forest Management GroupTechnical University of MunichFreisingGermany
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14
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Fremout T, Thomas E, Gaisberger H, Van Meerbeek K, Muenchow J, Briers S, Gutierrez-Miranda CE, Marcelo-Peña JL, Kindt R, Atkinson R, Cabrera O, Espinosa CI, Aguirre-Mendoza Z, Muys B. Mapping tree species vulnerability to multiple threats as a guide to restoration and conservation of tropical dry forests. GLOBAL CHANGE BIOLOGY 2020; 26:3552-3568. [PMID: 32020698 DOI: 10.1111/gcb.15028] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Understanding the vulnerability of tree species to anthropogenic threats is important for the efficient planning of restoration and conservation efforts. We quantified and compared the effects of future climate change and four current threats (fire, habitat conversion, overgrazing and overexploitation) on the 50 most common tree species of the tropical dry forests of northwestern Peru and southern Ecuador. We used an ensemble modelling approach to predict species distribution ranges, employed freely accessible spatial datasets to map threat exposures, and developed a trait-based scoring approach to estimate species-specific sensitivities, using differentiated trait weights in accordance with their expected importance in determining species sensitivities to specific threats. Species-specific vulnerability maps were constructed from the product of the exposure maps and the sensitivity estimates. We found that all 50 species face considerable threats, with an average of 46% of species' distribution ranges displaying high or very high vulnerability to at least one of the five threats. Our results suggest that current levels of habitat conversion, overexploitation and overgrazing pose larger threats to most of the studied species than climate change. We present a spatially explicit planning strategy for species-specific restoration and conservation actions, proposing management interventions to focus on (a) in situ conservation of tree populations and seed collection for tree planting activities in areas with low vulnerability to climate change and current threats; (b) ex situ conservation or translocation of populations in areas with high climate change vulnerability; and (c) active planting or assisted regeneration in areas under high current threat vulnerability but low climate change vulnerability, provided that interventions are in place to lower threat pressure. We provide an online, user-friendly tool to visualize both the vulnerability maps and the maps indicating priority restoration and conservation actions.
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Affiliation(s)
- Tobias Fremout
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium
- Alliance Bioversity International - CIAT, Lima, Peru
| | - Evert Thomas
- Alliance Bioversity International - CIAT, Lima, Peru
| | | | - Koenraad Van Meerbeek
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium
| | - Jannes Muenchow
- Institute of Geography, Friedrich Schiller University, Jena, Germany
| | - Siebe Briers
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium
| | | | | | | | | | - Omar Cabrera
- Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, Loja, Ecuador
| | - Carlos I Espinosa
- Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, Loja, Ecuador
| | | | - Bart Muys
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium
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15
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Krönke J, Wunderling N, Winkelmann R, Staal A, Stumpf B, Tuinenburg OA, Donges JF. Dynamics of tipping cascades on complex networks. Phys Rev E 2020; 101:042311. [PMID: 32422827 DOI: 10.1103/physreve.101.042311] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 03/18/2020] [Indexed: 01/02/2023]
Abstract
Tipping points occur in diverse systems in various disciplines such as ecology, climate science, economy, and engineering. Tipping points are critical thresholds in system parameters or state variables at which a tiny perturbation can lead to a qualitative change of the system. Many systems with tipping points can be modeled as networks of coupled multistable subsystems, e.g., coupled patches of vegetation, connected lakes, interacting climate tipping elements, and multiscale infrastructure systems. In such networks, tipping events in one subsystem are able to induce tipping cascades via domino effects. Here, we investigate the effects of network topology on the occurrence of such cascades. Numerical cascade simulations with a conceptual dynamical model for tipping points are conducted on Erdős-Rényi, Watts-Strogatz, and Barabási-Albert networks. Additionally, we generate more realistic networks using data from moisture-recycling simulations of the Amazon rainforest and compare the results to those obtained for the model networks. We furthermore use a directed configuration model and a stochastic block model which preserve certain topological properties of the Amazon network to understand which of these properties are responsible for its increased vulnerability. We find that clustering and spatial organization increase the vulnerability of networks and can lead to tipping of the whole network. These results could be useful to evaluate which systems are vulnerable or robust due to their network topology and might help us to design or manage systems accordingly.
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Affiliation(s)
- Jonathan Krönke
- Earth System Analysis, Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, 14473 Potsdam, Germany.,Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany
| | - Nico Wunderling
- Earth System Analysis, Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, 14473 Potsdam, Germany.,Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany.,Department of Physics, Humboldt University of Berlin, 12489 Berlin, Germany
| | - Ricarda Winkelmann
- Earth System Analysis, Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, 14473 Potsdam, Germany.,Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany
| | - Arie Staal
- Stockholm Resilience Centre, Stockholm University, 10691 Stockholm, Sweden
| | - Benedikt Stumpf
- Earth System Analysis, Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, 14473 Potsdam, Germany.,Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Obbe A Tuinenburg
- Stockholm Resilience Centre, Stockholm University, 10691 Stockholm, Sweden.,Copernicus Institute, Faculty of Geosciences, Utrecht University, 3584 CB Utrecht, The Netherlands
| | - Jonathan F Donges
- Earth System Analysis, Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, 14473 Potsdam, Germany.,Stockholm Resilience Centre, Stockholm University, 10691 Stockholm, Sweden
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16
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Meng Y, Liu X, Ding C, Xu B, Zhou G, Zhu L. Analysis of ecological resilience to evaluate the inherent maintenance capacity of a forest ecosystem using a dense Landsat time series. ECOL INFORM 2020. [DOI: 10.1016/j.ecoinf.2020.101064] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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17
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Sansevero JB, Garbin ML, Sánchez-Tapia A, Valladares F, Scarano FR. Fire drives abandoned pastures to a savanna-like state in the Brazilian Atlantic Forest. Perspect Ecol Conserv 2020. [DOI: 10.1016/j.pecon.2019.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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18
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Forest and Land Fires Are Mainly Associated with Deforestation in Riau Province, Indonesia. REMOTE SENSING 2019. [DOI: 10.3390/rs12010003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Indonesia has experienced extensive land-cover change and frequent vegetation and land fires in the past few decades. We combined a new land-cover dataset with satellite data on the timing and location of fires to make the first detailed assessment of the association of fire with specific land-cover transitions in Riau, Sumatra. During 1990 to 2017, secondary peat swamp forest declined in area from 40,000 to 10,000 km2 and plantations (including oil palm) increased from around 10,000 to 40,000 km2. The dominant land use transitions were secondary peat swamp forest converting directly to plantation, or first to shrub and then to plantation. During 2001–2017, we find that the frequency of fire is greatest in regions that change land-cover, with the greatest frequency in regions that transition from secondary peat swamp forest to shrub or plantation (0.15 km−2 yr−1). Areas that did not change land cover exhibit lower fire frequency, with shrub (0.06 km−2 yr−1) exhibiting a frequency of fire >60 times the frequency of fire in primary forest. Our analysis demonstrates that in Riau, fire is closely connected to land-cover change, and that the majority of fire is associated with the transition of secondary forest to shrub and plantation. Reducing the frequency of fire in Riau will require enhanced protection of secondary forests and restoration of shrub to natural forest.
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19
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Relationship Between Fire and Forest Cover Loss in Riau Province, Indonesia Between 2001 and 2012. FORESTS 2019. [DOI: 10.3390/f10100889] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Forest and peatland fires occur regularly across Indonesia, resulting in large greenhouse gas emissions and causing major air quality issues. Over the last few decades, Indonesia has also experienced extensive forest loss and conversion of natural forest to oil palm and timber plantations. Here we used data on fire hotspots and tree-cover loss, as well as information on the extent of peat land, protected areas, and concessions to explore spatial and temporal relationships among forest, forest loss, and fire frequency. We focus on the Riau Province in Central Sumatra, one of the most active regions of fire in Indonesia. We find strong relationships between forest loss and fire at the local scale. Regions with forest loss experienced six times as many fire hotspots compared to regions with no forest loss. Forest loss and maximum fire frequency occurred within the same year, or one year apart, in 70% of the 1 km2 cells experiencing both forest loss and fire. Frequency of fire was lower both before and after forest loss, suggesting that most fire is associated with the forest loss process. On peat soils, fire frequency was a factor 10 to 100 lower in protected areas and natural forest logging concessions compared to oil palm and wood fiber (timber) concessions. Efforts to reduce fire need to address the underlying role of land-use and land-cover change in the occurrence of fire. Increased support for protected areas and natural forest logging concessions and restoration of degraded peatlands may reduce future fire risk. During times of high fire risk, fire suppression resources should be targeted to regions that are experiencing recent forest loss, as these regions are most likely to experience fire.
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20
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Patchy Fires Promote Regeneration of Longleaf Pine (Pinus palustris Mill.) in Pine Savannas. FORESTS 2019. [DOI: 10.3390/f10050367] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Research Highlights: Spatial patterns of fire spread and severity influence survival of juvenile pines in longleaf pine savannas. Small areas that do not burn during frequent fires facilitate formation of patches of even-aged longleaf pine juveniles. These regeneration patches are especially associated with inner portions of openings (gaps) and where canopy trees have died in recent decades. Patterns of prescribed fire can thus have an important influence on stand dynamics of the dominant tree in pine savannas. Background and Objectives: Savannas are characterized by bottlenecks to tree regeneration. In pine savannas, longleaf pine is noted for recruitment in discrete clusters located within gaps away from canopy trees. Various mechanisms promoting this pattern have been hypothesized: light limitations, soil moisture, soil nutrients, pine needle mulching, competition with canopy tree roots, and fire severity associated with pine needle litter. We tested the hypothesis that regeneration patches are associated with areas that remain unburned during some prescribed fires, as mediated by gaps in the canopy, especially inner portions of gaps, and areas re-opened by death of canopy trees. Materials and Methods: We mapped areas that were unburned during prescribed fires applied at 1–2 year intervals from 2005–2018 in an old-growth pine savanna in Georgia, USA. We compared the maps to locations of longleaf pine juveniles (<1.5 m height) measured in 2018 and canopy cover and canopy tree deaths using a long-term (40 year) tree census. Results: Logistic regression analysis showed juveniles to be associated with unburned areas, gaps, inner gaps, and areas where canopy trees died. Conclusions: Patterns of fire spread and severity limit survival of longleaf pine juveniles to patches away from canopy trees, especially where canopy trees have died in recent decades. These processes contribute to a buffering mechanism that maintains the savanna structure and prevents transition to closed canopy forest or open grassland communities.
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