1
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Higgins SI, Banerjee S, Baudena M, Bowman DMJS, Conradi T, Couteron P, Kruger LM, O'Hara RB, Williamson GJ. Reassessing the alternative ecosystem states proposition in the African savanna-forest domain. THE NEW PHYTOLOGIST 2024; 243:1660-1669. [PMID: 38982706 DOI: 10.1111/nph.19911] [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: 03/09/2024] [Accepted: 05/26/2024] [Indexed: 07/11/2024]
Abstract
Ecologists are being challenged to predict how ecosystems will respond to climate changes. According to the Multi-Colored World (MCW) hypothesis, climate impacts may not manifest because consumers such as fire and herbivory can override the influence of climate on ecosystem state. One MCW interpretation is that climate determinism fails because alternative ecosystem states (AES) are possible at some locations in climate space. We evaluated theoretical and empirical evidence for the proposition that forest and savanna are AES in Africa. We found that maps which infer where AES zones are located were contradictory. Moreover, data from longitudinal and experimental studies provide inconclusive evidence for AES. That is, although the forest-savanna AES proposition is theoretically sound, the existing evidence is not yet convincing. We conclude by making the case that the AES proposition has such fundamental consequences for designing management actions to mitigate and adapt to climate change in the savanna-forest domain that it needs a more robust evidence base before it is used to prescribe management actions.
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Affiliation(s)
- Steven I Higgins
- Plant Ecology, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Swarnendu Banerjee
- Dutch Institute for Emergent Phenomena, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE, Amsterdam, the Netherlands
- Copernicus Institute of Sustainable Development, Utrecht University, 3508 TC, Utrecht, the Netherlands
| | - Mara Baudena
- National Research Council, Institute of Atmospheric Sciences and Climate (CNR-ISAC), 10133, Torino, Italy
- National Biodiversity Future Center (NBFC), 90133, Palermo, Italy
| | - David M J S Bowman
- Fire, Centre, School of Natural Sciences, University of Tasmania, 7005 Sandy Bay, Hobart, Tas., Australia
| | - Timo Conradi
- Plant Ecology, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Pierre Couteron
- AMAP, University of Montpellier, IRD, CNRS, INRAE, CIRAD, 34394, Montpellier, France
| | - Laurence M Kruger
- Organization for Tropical Studies, PO Box 33, Skukuza, 1350, South Africa
| | - Robert B O'Hara
- Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Grant J Williamson
- Fire, Centre, School of Natural Sciences, University of Tasmania, 7005 Sandy Bay, Hobart, Tas., Australia
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2
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Eppinga MB, Michaels TK, Santos MJ, Bever JD. Introducing desirable patches to initiate ecosystem transitions and accelerate ecosystem restoration. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2910. [PMID: 37602903 DOI: 10.1002/eap.2910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 05/30/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023]
Abstract
Meeting restoration targets may require active strategies to accelerate natural regeneration rates or overcome the resilience associated with degraded ecosystem states. Introducing desired ecosystem patches in degraded landscapes constitutes a promising active restoration strategy, with various mechanisms potentially causing these patches to become foci from which desired species can re-establish throughout the landscape. This study considers three mechanisms previously identified as potential drivers of introduced patch dynamics: autocatalytic nucleation, directed dispersal, and resource concentration. These mechanisms reflect qualitatively different positive feedbacks. We developed an ecological model framework that compared how the occurrence of each mechanism was reflected in spatio-temporal patch dynamics. We then analyzed the implications of these relationships for optimal restoration design. We found that patch expansion accelerated over time when driven by the autocatalytic nucleation mechanism, while patch expansion driven by the directed dispersal or resource concentration mechanisms decelerated over time. Additionally, when driven by autocatalytic nucleation, patch expansion was independent of patch position in the landscape. However, the proximity of other patches affected patch expansion either positively or negatively when driven by directed dispersal or resource concentration. For autocatalytic nucleation, introducing many small patches was a favorable strategy, provided that each individual patch exceeded a critical patch size. Introducing a single patch or a few large patches was the most effective restoration strategy to initiate the directed dispersal mechanism. Introducing many small patches was the most effective strategy for reaching restored ecosystem states driven by a resource concentration mechanism. Our model results suggest that introducing desirable patches can substantially accelerate ecosystem restoration, or even induce a critical transition from an otherwise stable degraded state toward a desired ecosystem state. However, the potential of this type of restoration strategy for a particular ecosystem may strongly depend on the mechanism driving patch dynamics. In turn, which mechanism drives patch dynamics may affect the optimal spatial design of an active restoration strategy. Each of the three mechanisms considered reflects distinct spatio-temporal patch dynamics, providing novel opportunities for empirically identifying key mechanisms, and restoration designs that introduce desired patches in degraded landscapes according to these patch dynamics.
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Affiliation(s)
| | - Theo K Michaels
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
- Kansas Biological Survey, University of Kansas, Lawrence, Kansas, USA
| | - Maria J Santos
- Department of Geography, University of Zurich, Zurich, Switzerland
| | - James D Bever
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
- Kansas Biological Survey, University of Kansas, Lawrence, Kansas, USA
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3
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Cui X, Dai D, Huang C, Wang B, Li S, You C, Paterson AM, Perry GLW, Buckley HL, Cubino JP, Wyse SV, Alam MA, Zhou S, Xiao L, Cao D, Xu Z, Curran TJ. Climatic conditions affect shoot flammability by influencing flammability-related functional traits in nonfire-prone habitats. THE NEW PHYTOLOGIST 2023; 240:105-113. [PMID: 36960541 DOI: 10.1111/nph.18905] [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: 01/12/2023] [Accepted: 03/16/2023] [Indexed: 06/18/2023]
Abstract
Plant flammability is an important driver of wildfires, and flammability itself is determined by several plant functional traits. While many plant traits are influenced by climatic conditions, the interaction between climatic conditions and plant flammability has rarely been investigated. Here, we explored the relationships among climatic conditions, shoot-level flammability components, and flammability-related functional traits for 186 plant species from fire-prone and nonfire-prone habitats. For species originating from nonfire-prone habitats, those from warmer areas tended to have lower shoot moisture content and larger leaves, and had higher shoot flammability with higher ignitibility, combustibility, and sustainability. Plants in wetter areas tended to have lower shoot flammability with lower combustibility and sustainability due to higher shoot moisture contents. In fire-prone habitats, shoot flammability was not significantly related to any climatic factor. Our study suggests that for species originating in nonfire-prone habitats, climatic conditions have influenced plant flammability by shifting flammability-related functional traits, including leaf size and shoot moisture content. Climate does not predict shoot flammability in species from fire-prone habitats; here, fire regimes may have an important role in shaping plant flammability. Understanding these nuances in the determinants of plant flammability is important in an increasingly fire-prone world.
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Affiliation(s)
- Xinglei Cui
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River, Key Laboratory of Sichuan Province, National Forestry and Grassland Administration, Chengdu, 611130, China
| | - Dachuan Dai
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
| | - Congde Huang
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River, Key Laboratory of Sichuan Province, National Forestry and Grassland Administration, Chengdu, 611130, China
| | - Bilei Wang
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
| | - Shuting Li
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
| | - Chengming You
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
| | - Adrian M Paterson
- Department of Pest-management and Conservation, Lincoln University, Lincoln, 7647, New Zealand
| | - George L W Perry
- School of Environment, University of Auckland, Auckland, 1142, New Zealand
| | - Hannah L Buckley
- School of Science, Auckland University of Technology, Auckland, 1010, New Zealand
| | - Josep Padullés Cubino
- Centre for Ecological Research and Forestry Applications (CREAF), Cerdanyola del Vallès, 8193, Spain
| | - Sarah V Wyse
- School of Forestry, University of Canterbury, Christchurch, 7910, New Zealand
| | - Md Azharul Alam
- Department of Pest-management and Conservation, Lincoln University, Lincoln, 7647, New Zealand
| | - Shixing Zhou
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River, Key Laboratory of Sichuan Province, National Forestry and Grassland Administration, Chengdu, 611130, China
| | - Lin Xiao
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
| | - Dongyu Cao
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
| | - Zhenfeng Xu
- Engineering Research Centre for Southwest Forest and Grassland Fire Ecological Prevention, College of Forestry, National Forestry and Grassland Administration, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River, Key Laboratory of Sichuan Province, National Forestry and Grassland Administration, Chengdu, 611130, China
| | - Timothy J Curran
- Department of Pest-management and Conservation, Lincoln University, Lincoln, 7647, New Zealand
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González-Barrios FJ, Estrada-Saldívar N, Pérez-Cervantes E, Secaira-Fajardo F, Álvarez-Filip L. Legacy effects of anthropogenic disturbances modulate dynamics in the world's coral reefs. GLOBAL CHANGE BIOLOGY 2023; 29:3285-3303. [PMID: 36932916 DOI: 10.1111/gcb.16686] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/03/2023] [Accepted: 03/07/2023] [Indexed: 05/16/2023]
Abstract
Rapidly changing conditions alter disturbance patterns, highlighting the need to better understand how the transition from pulse disturbances to more persistent stress will impact ecosystem dynamics. We conducted a global analysis of the impacts of 11 types of disturbances on reef integrity using the rate of change of coral cover as a measure of damage. Then, we evaluated how the magnitude of the damage due to thermal stress, cyclones, and diseases varied among tropical Atlantic and Indo-Pacific reefs and whether the cumulative impact of thermal stress and cyclones was able to modulate the responses of reefs to future events. We found that reef damage largely depends on the condition of a reef before a disturbance, disturbance intensity, and biogeographic region, regardless of the type of disturbance. Changes in coral cover after thermal stress events were largely influenced by the cumulative stress of past disturbances and did not depend on disturbance intensity or initial coral cover, which suggests that an ecological memory is present within coral communities. In contrast, the effect of cyclones (and likely other physical impacts) was primarily modulated by the initial reef condition and did not appear to be influenced by previous impacts. Our findings also underscore that coral reefs can recover if stressful conditions decrease, yet the lack of action to reduce anthropogenic impacts and greenhouse gas emissions continues to trigger reef degradation. We uphold that evidence-based strategies can guide managers to make better decisions to prepare for future disturbances.
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Affiliation(s)
- F Javier González-Barrios
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Nuria Estrada-Saldívar
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Esmeralda Pérez-Cervantes
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | | | - Lorenzo Álvarez-Filip
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
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5
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Zhou H, Hou L, Lv X, Yang G, Wang Y, Wang X. Compensatory growth as a response to post-drought in grassland. FRONTIERS IN PLANT SCIENCE 2022; 13:1004553. [PMID: 36531403 PMCID: PMC9752846 DOI: 10.3389/fpls.2022.1004553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
Grasslands are structurally and functionally controlled by water availability. Ongoing global change is threatening the sustainability of grassland ecosystems through chronic alterations in climate patterns and resource availability, as well as by the increasing frequency and intensity of anthropogenic perturbations. Compared with many studies on how grassland ecosystems respond during drought, there are far fewer studies focused on grassland dynamics after drought. Compensatory growth, as the ability of plants to offset the adverse effects of environmental or anthropogenic perturbations, is a common phenomenon in grassland. However, compensatory growth induced by drought and its underlying mechanism across grasslands remains not clear. In this review, we provide examples of analogous compensatory growth from different grassland types across drought characteristics (intensity, timing, and duration) and explain the effect of resource availability on compensatory growth and their underlying mechanisms. Based on our review of the literature, a hypothetic framework for integrating plant, root, and microbial responses is also proposed to increase our understanding of compensatory growth after drought. This research will advance our understanding of the mechanisms of grassland ecosystem functioning in response to climate change.
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Affiliation(s)
- Huailin Zhou
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing, China
| | - Lulu Hou
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaomin Lv
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing, China
| | - Guang Yang
- College of Teacher Education, Capital Normal University, Beijing, China
| | - Yuhui Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Xu Wang
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
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6
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Turner MG, Braziunas KH, Hansen WD, Hoecker TJ, Rammer W, Ratajczak Z, Westerling AL, Seidl R. The magnitude, direction, and tempo of forest change in Greater Yellowstone in a warmer world with more fire. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1485] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Monica G. Turner
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Kristin H. Braziunas
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Winslow D. Hansen
- Earth Institute Columbia University New York City New York 10025 USA
| | - Tyler J. Hoecker
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Werner Rammer
- School of Life Sciences Technical University of Munich 85354 Freising Germany
| | - Zak Ratajczak
- Department of Biology Kansas State University Manhattan Kansas 66506‐4901 USA
| | - A. Leroy Westerling
- Sierra Nevada Research Institute and School of Engineering University of California‐Merced Merced California 95343 USA
| | - Rupert Seidl
- School of Life Sciences Technical University of Munich 85354 Freising Germany
- Berchtesgaden National Park 83471 Berchtesgaden Germany
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7
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Schultz EL, Hülsmann L, Pillet MD, Hartig F, Breshears DD, Record S, Shaw JD, DeRose RJ, Zuidema PA, Evans MEK. Climate-driven, but dynamic and complex? A reconciliation of competing hypotheses for species' distributions. Ecol Lett 2021; 25:38-51. [PMID: 34708503 DOI: 10.1111/ele.13902] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 08/19/2021] [Accepted: 09/18/2021] [Indexed: 12/01/2022]
Abstract
Estimates of the percentage of species "committed to extinction" by climate change range from 15% to 37%. The question is whether factors other than climate need to be included in models predicting species' range change. We created demographic range models that include climate vs. climate-plus-competition, evaluating their influence on the geographic distribution of Pinus edulis, a pine endemic to the semiarid southwestern U.S. Analyses of data on 23,426 trees in 1941 forest inventory plots support the inclusion of competition in range models. However, climate and competition together only partially explain this species' distribution. Instead, the evidence suggests that climate affects other range-limiting processes, including landscape-scale, spatial processes such as disturbances and antagonistic biotic interactions. Complex effects of climate on species distributions-through indirect effects, interactions, and feedbacks-are likely to cause sudden changes in abundance and distribution that are not predictable from a climate-only perspective.
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Affiliation(s)
- Emily L Schultz
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA
| | - Lisa Hülsmann
- Theoretical Ecology Lab, University of Regensburg, Regensburg, Germany
| | - Michiel D Pillet
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA.,Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
| | - Florian Hartig
- Theoretical Ecology Lab, University of Regensburg, Regensburg, Germany
| | - David D Breshears
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
| | - Sydne Record
- Department of Biology, Bryn Mawr College, Bryn Mawr, Pennsylvania, USA
| | - John D Shaw
- USDA Forest Service, Rocky Mountain Research Station, Forest Inventory and Analysis, Ogden, Utah, USA
| | - R Justin DeRose
- Department of Wildland Resources, Utah State University, Logan, Utah, USA
| | - Pieter A Zuidema
- Forest Ecology and Forest Management group, Wageningen University and Research, Wageningen, The Netherlands
| | - Margaret E K Evans
- Laboratory of Tree Ring Research, University of Arizona, Tucson, Arizona, USA.,Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
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8
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Jager HI, Long JW, Malison RL, Murphy BP, Rust A, Silva LGM, Sollmann R, Steel ZL, Bowen MD, Dunham JB, Ebersole JL, Flitcroft RL. Resilience of terrestrial and aquatic fauna to historical and future wildfire regimes in western North America. Ecol Evol 2021; 11:12259-12284. [PMID: 34594498 PMCID: PMC8462151 DOI: 10.1002/ece3.8026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/12/2021] [Accepted: 07/24/2021] [Indexed: 01/08/2023] Open
Abstract
Wildfires in many western North American forests are becoming more frequent, larger, and severe, with changed seasonal patterns. In response, coniferous forest ecosystems will transition toward dominance by fire-adapted hardwoods, shrubs, meadows, and grasslands, which may benefit some faunal communities, but not others. We describe factors that limit and promote faunal resilience to shifting wildfire regimes for terrestrial and aquatic ecosystems. We highlight the potential value of interspersed nonforest patches to terrestrial wildlife. Similarly, we review watershed thresholds and factors that control the resilience of aquatic ecosystems to wildfire, mediated by thermal changes and chemical, debris, and sediment loadings. We present a 2-dimensional life history framework to describe temporal and spatial life history traits that species use to resist wildfire effects or to recover after wildfire disturbance at a metapopulation scale. The role of fire refuge is explored for metapopulations of species. In aquatic systems, recovery of assemblages postfire may be faster for smaller fires where unburned tributary basins or instream structures provide refuge from debris and sediment flows. We envision that more-frequent, lower-severity fires will favor opportunistic species and that less-frequent high-severity fires will favor better competitors. Along the spatial dimension, we hypothesize that fire regimes that are predictable and generate burned patches in close proximity to refuge will favor species that move to refuges and later recolonize, whereas fire regimes that tend to generate less-severely burned patches may favor species that shelter in place. Looking beyond the trees to forest fauna, we consider mitigation options to enhance resilience and buy time for species facing a no-analog future.
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Affiliation(s)
- Henriette I. Jager
- Environmental Sciences DivisionOak Ridge National Laboratory (ORNL)Oak RidgeTNUSA
| | - Jonathan W. Long
- U.S. Department of AgriculturePacific Southwest Research StationDavisCAUSA
| | - Rachel L. Malison
- Flathead Lake Biological StationThe University of MontanaPolsonMTUSA
| | - Brendan P. Murphy
- School of Environmental ScienceSimon Fraser UniversityBurnabyBCCanada
| | - Ashley Rust
- Civil and Environmental Engineering DepartmentColorado School of MinesGoldenCOUSA
| | - Luiz G. M. Silva
- Institute for Land, Water and SocietyCharles Sturt UniversityAlburyNSWAustralia
- Department of CivilEnvironmental and Geomatic EngineeringStocker LabInstitute of Environmental EngineeringETH ZurichZürichSwitzerland
| | - Rahel Sollmann
- Department of Wildlife, Fish, and Conservation BiologyUniversity of California DavisDavisCAUSA
| | - Zachary L. Steel
- Department of Environmental Science, Policy and ManagementUniversity of CaliforniaBerkeleyCAUSA
| | - Mark D. Bowen
- Thomas Gast & Associates Environmental ConsultantsArcataCAUSA
| | - Jason B. Dunham
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science CenterCorvallisORUSA
| | - Joseph L. Ebersole
- Center for Public Health and Environmental AssessmentPacific Ecological Systems DivisionU.S. Environmental Protection AgencyCorvallisORUSA
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9
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Carroll C, Noss RF. Rewilding in the face of climate change. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2021; 35:155-167. [PMID: 32557877 PMCID: PMC7984084 DOI: 10.1111/cobi.13531] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 01/21/2020] [Accepted: 03/15/2020] [Indexed: 06/02/2023]
Abstract
Expansion of the global protected-area network has been proposed as a strategy to address threats from accelerating climate change and species extinction. A key step in increasing the effectiveness of such expansion is understanding how novel threats to biodiversity from climate change alter concepts such as rewilding, which have underpinned many proposals for large interconnected reserves. We reviewed potential challenges that climate change poses to rewilding and found that the conservation value of large protected areas persists under climate change. Nevertheless, more attention should be given to protection of microrefugia, macrorefugia, complete environmental gradients, and areas that connect current and future suitable climates and to maintaining ecosystem processes and stabilizing feedbacks via conservation strategies that are resilient to uncertainty regarding climate trends. Because a major element of the threat from climate change stems from its novel geographic patterns, we examined, as an example, the implications for climate-adaptation planning of latitudinal, longitudinal (continental to maritime), and elevational gradients in climate-change exposure across the Yellowstone-to-Yukon region, the locus of an iconic conservation proposal initially designed to conserve wide-ranging carnivore species. In addition to a continued emphasis on conserving intact landscapes, restoration of degraded low-elevation areas within the region is needed to capture sites important for landscape-level climate resilience. Extreme climate exposure projected for boreal North America suggests the need for ambitious goals for expansion of the protected-area network there to include refugia created by topography and ecological features, such as peatlands, whose conservation can also reduce emissions from carbon stored in soil. Qualitative understanding of underlying reserve design rules and the geography of climate-change exposure can strengthen the outcomes of inclusive regional planning processes that identify specific sites for protection.
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Affiliation(s)
- Carlos Carroll
- Klamath Center for Conservation ResearchOrleansCA95556U.S.A.
| | - Reed F. Noss
- Florida Institute for Conservation ScienceMelroseFL32666U.S.A.
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10
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Meyer JM, Leempoel K, Losapio G, Hadly EA. Molecular Ecological Network Analyses: An Effective Conservation Tool for the Assessment of Biodiversity, Trophic Interactions, and Community Structure. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.588430] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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11
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Bowman DMJS. Using a natural experiment to foresee the fate of boreal carbon stores. GLOBAL CHANGE BIOLOGY 2020; 26:6028-6031. [PMID: 32515848 DOI: 10.1111/gcb.15214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
Dieleman et al. (Global Change Biology, 2020) undertook a meticulously designed and naturally executed experiment that revealed substantial legacy effects of past logging and fire disturbance on aboveground and belowground carbon losses following major wildfires that occurred in 2015 in southern boreal forests in central Saskatchewan, Canada. Such natural experiments are a critical element in Earth System science because they frame questions, refine hypotheses and generate empirical data essential for predicting the fate of global carbon stores in an increasingly fire prone world. This article is a Commentary on Dieleman et al., 26, 6062-6079.
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Affiliation(s)
- David M J S Bowman
- School of Natural Sciences, University of Tasmania, Hobart, Tas., Australia
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12
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Johnstone JF, Celis G, Chapin FS, Hollingsworth TN, Jean M, Mack MC. Factors shaping alternate successional trajectories in burned black spruce forests of Alaska. Ecosphere 2020. [DOI: 10.1002/ecs2.3129] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- J. F. Johnstone
- Institute of Arctic Biology University of Alaska Fairbanks Fairbanks Alaska 99775 USA
- Department of Biology University of Saskatchewan Saskatoon Saskatchewan S7N 5A2 Canada
| | - G. Celis
- Department of Biological Sciences Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86001 USA
| | - F. S. Chapin
- Institute of Arctic Biology University of Alaska Fairbanks Fairbanks Alaska 99775 USA
| | - T. N. Hollingsworth
- Institute of Arctic Biology University of Alaska Fairbanks Fairbanks Alaska 99775 USA
- PNW Research Station USDA Forest Service Fairbanks Alaska 99775 USA
| | - M. Jean
- Department of Biology University of Saskatchewan Saskatoon Saskatchewan S7N 5A2 Canada
- Department of Biological Sciences Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86001 USA
| | - M. C. Mack
- Department of Biological Sciences Center for Ecosystem Science and Society Northern Arizona University Flagstaff Arizona 86001 USA
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13
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Pausas JG, Bond WJ. Alternative Biome States in Terrestrial Ecosystems. TRENDS IN PLANT SCIENCE 2020; 25:250-263. [PMID: 31917105 DOI: 10.1016/j.tplants.2019.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 11/06/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
There is growing interest in the application of alternative stable state (ASS) theory to explain major vegetation patterns of the world. Here, we introduce the theory as applied to the puzzle of nonforested (open) biomes growing in climates that are warm and wet enough to support forests (alternative biome states, ABSs). Long thought to be the product of deforestation, diverse lines of evidence indicate that many open ecosystems are ancient. They have also been characterized as 'early successional' even where they persist for millennia. ABS is an alternative framework to that of climate determinism and succession for exploring forest/nonforest mosaics. This framework explains not only tropical forest-savanna landscapes, but also other landscape mosaics across the globe.
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Affiliation(s)
- Juli G Pausas
- Centro de Investigaciones sobre Desertificación (CIDE-CSIC), 46113 Montcada, Valencia, Spain.
| | - William J Bond
- Department of Biological Sciences, University of Cape Town, Rondebosch 7701, Cape Town, South Africa; South African Environmental Observation Network, National Research Foundation, Private Bag X7, Claremont 7735, South Africa
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14
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Davies KW, Rios RC, Bates JD, Johnson DD, Kerby J, Boyd CS. To burn or not to burn: Comparing reintroducing fire with cutting an encroaching conifer for conservation of an imperiled shrub-steppe. Ecol Evol 2019; 9:9137-9148. [PMID: 31463011 PMCID: PMC6706219 DOI: 10.1002/ece3.5461] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/13/2019] [Accepted: 07/02/2019] [Indexed: 11/09/2022] Open
Abstract
Woody vegetation has increased on rangelands worldwide for the past 100-200 years, often because of reduced fire frequency. However, there is a general aversion to reintroducing fire, and therefore, fire surrogates are often used in its place to reverse woody plant encroachment. Determining the conservation effectiveness of reintroducing fire compared with fire surrogates over different time scales is needed to improve conservation efforts. We evaluated the conservation effectiveness of reintroducing fire with a fire surrogate (cutting) applied over the last ~30 years to control juniper (Juniperus occidentalis Hook.) encroachment on 77 sagebrush-steppe sites. Critical to conservation of this imperiled ecosystem is to limit juniper, not encourage exotic annual grasses, and promote sagebrush dominance of the overstory. Reintroducing fire was more effective than cutting at reducing juniper abundance and extending the period of time that juniper was not dominating the plant community. Sagebrush was reduced more with burning than cutting. Sagebrush, however, was predicted to be a substantial component of the overstory longer in burned than cut areas because of more effective juniper control. Variation in exotic annual grass cover was explained by environmental variables and perennial grass abundance, but not treatment, with annual grasses being problematic on hotter and drier sites with less perennial grass. This suggests that ecological memory varies along an environmental gradient. Reintroducing fire was more effective than cutting at conserving sagebrush-steppe encroached by juniper over extended time frames; however, cutting was more effective for short-term conservation. This suggests fire and fire surrogates both have critical roles in conservation of imperiled ecosystems.
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15
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Yletyinen J, Brown P, Pech R, Hodges D, Hulme PE, Malcolm TF, Maseyk FJF, Peltzer DA, Perry GLW, Richardson SJ, Smaill SJ, Stanley MC, Todd JH, Walsh PJ, Wright W, Tylianakis JM. Understanding and Managing Social–Ecological Tipping Points in Primary Industries. Bioscience 2019. [DOI: 10.1093/biosci/biz031] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Johanna Yletyinen
- School of Biological Sciences, University of Canterbury in Christchurch, New Zealand
- Manaaki Whenua Landcare Research Ltd. branches in Lincoln, Wellington and Auckland, in New Zealand
| | - Philip Brown
- Manaaki Whenua Landcare Research Ltd. branches in Lincoln, Wellington and Auckland, in New Zealand
| | - Roger Pech
- Manaaki Whenua Landcare Research Ltd. branches in Lincoln, Wellington and Auckland, in New Zealand
| | | | - Philip E Hulme
- Bio-Protection Research Centre at Lincoln University, New Zealand
| | | | - Fleur J F Maseyk
- The Catalyst Group, in Wellington, New Zealand, and with the Centre for Biodiversity and Conservation Science at the University of Queensland in Brisbane, Australia
| | - Duane A Peltzer
- Manaaki Whenua Landcare Research Ltd. branches in Lincoln, Wellington and Auckland, in New Zealand
| | - George L W Perry
- School of Environment at the University of Auckland, New Zealand
| | - Sarah J Richardson
- Manaaki Whenua Landcare Research Ltd. branches in Lincoln, Wellington and Auckland, in New Zealand
| | | | - Margaret C Stanley
- School of Biological Sciences, at the University of Auckland, New Zealand
| | - Jacqui H Todd
- The New Zealand Institute for Plant and Food Research, Ltd., in Auckland, and Willie Wright is affiliated with the Integrated Kaipara Harbour Management Group, in Whangarei, New Zealand
| | - Patrick J Walsh
- Manaaki Whenua Landcare Research Ltd. branches in Lincoln, Wellington and Auckland, in New Zealand
| | - Willie Wright
- School of Biological Sciences, University of Canterbury in Christchurch, New Zealand
| | - Jason M Tylianakis
- School of Biological Sciences, University of Canterbury in Christchurch, New Zealand
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16
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Hart SJ, Henkelman J, McLoughlin PD, Nielsen SE, Truchon-Savard A, Johnstone JF. Examining forest resilience to changing fire frequency in a fire-prone region of boreal forest. GLOBAL CHANGE BIOLOGY 2019; 25:869-884. [PMID: 30570807 DOI: 10.1111/gcb.14550] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/09/2018] [Accepted: 12/04/2018] [Indexed: 06/09/2023]
Abstract
Future changes in climate are widely anticipated to increase fire frequency, particularly in boreal forests where extreme warming is expected to occur. Feedbacks between vegetation and fire may modify the direct effects of warming on fire activity and shape ecological responses to changing fire frequency. We investigate these interactions using extensive field data from the Boreal Shield of Saskatchewan, Canada, a region where >40% of the forest has burned in the past 30 years. We use geospatial and field data to assess the resistance and resilience of eight common vegetation states to frequent fire by quantifying the occurrence of short-interval fires and their effect on recovery to a similar vegetation state. These empirical relationships are combined with data from published literature to parameterize a spatially explicit, state-and-transition simulation model of fire and forest succession. We use this model to ask if and how: (a) feedbacks between vegetation and wildfire may modify fire activity on the landscape, and (b) more frequent fire may affect landscape forest composition and age structure. Both field and GIS data suggest the probability of fire is low in the initial decades after fire, supporting the hypothesis that fuel accumulation may exert a negative feedback on fire frequency. Field observations of pre- and postfire composition indicate that switches in forest state are more likely in conifer stands that burn at a young age, supporting the hypothesis that resilience is lower in immature stands. Stands dominated by deciduous trees or jack pine were generally resilient to fire, while mixed conifer and well-drained spruce forests were less resilient. However, simulation modeling suggests increased fire activity may result in large changes in forest age structure and composition, despite the feedbacks between vegetation-fire likely to occur with increased fire activity.
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Affiliation(s)
- Sarah J Hart
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin
| | - Jonathan Henkelman
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Philip D McLoughlin
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Scott E Nielsen
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | | | - Jill F Johnstone
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska
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17
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Variation in vegetation cover and seedling performance of tree species in a forest-savanna ecotone. JOURNAL OF TROPICAL ECOLOGY 2019. [DOI: 10.1017/s0266467418000469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractDifferential tree seedling recruitment across forest-savanna ecotones is poorly understood, but hypothesized to be influenced by vegetation cover and associated factors. In a 3-y-long field transplant experiment in the forest-savanna ecotone of Ghana, we assessed performance and root allocation of 864 seedlings for two forest (Khaya ivorensis and Terminalia superba) and two savanna (Khaya senegalensis and Terminalia macroptera) species in savanna woodland, closed-woodland and forest. Herbaceous vegetation biomass was significantly higher in savanna woodland (1.0 ± 0.4 kg m−2 vs 0.2 ± 0.1 kg m−2 in forest) and hence expected fire intensities, while some soil properties were improved in forest. Regardless, seedling survival declined significantly in the first-year dry-season for all species with huge declines for the forest species (50% vs 6% for Khaya and 16% vs 2% for Terminalia) by year 2. After 3 y, only savanna species survived in savanna woodland. However, best performance for savanna Khaya was in forest, but in savanna woodland for savanna Terminalia which also had the highest biomass fraction (0.8 ± 0.1 g g−1 vs 0.6 ± 0.1 g g−1 and 0.4 ± 0.1 g g−1) and starch concentration (27% ± 10% vs 15% ± 7% and 10% ± 4%) in roots relative to savanna and forest Khaya respectively. Our results demonstrate that tree cover variation has species-specific effects on tree seedling recruitment which is related to root storage functions.
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18
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Braziunas KH, Hansen WD, Seidl R, Rammer W, Turner MG. Looking beyond the mean: Drivers of variability in postfire stand development of conifers in Greater Yellowstone. FOREST ECOLOGY AND MANAGEMENT 2018; 430:460-471. [PMID: 35645456 PMCID: PMC7612775 DOI: 10.1016/j.foreco.2018.08.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
High-severity, infrequent fires in forests shape landscape mosaics of stand age and structure for decades to centuries, and forest structure can vary substantially even among same-aged stands. This variability among stand structures can affect landscape-scale carbon and nitrogen cycling, wildlife habitat availability, and vulnerability to subsequent disturbances. We used an individual-based forest process model (iLand) to ask: Over 300 years of postfire stand development, how does variation in early regeneration densities versus abiotic conditions influence among-stand structural variability for four conifer species widespread in western North America? We parameterized iLand for lodgepole pine (Pinus contorta var. latifolia), Douglas-fir (Pseudotsuga menziesii var. glauca), Engelmann spruce (Picea engelmannii), and subalpine fir (Abies lasiocarpa) in Greater Yellowstone (USA). Simulations were initialized with field data on regeneration following stand-replacing fires, and stand development was simulated under historical climatic conditions without further disturbance. Stand structure was characterized by stand density and basal area. Stands became more similar in structure as time since fire increased. Basal area converged more rapidly among stands than tree density for Douglas-fir and lodgepole pine, but not for subalpine fir and Engelmann spruce. For all species, regeneration-driven variation in stand density persisted for at least 99 years postfire, and for lodgepole pine, early regeneration densities dictated among-stand variation for 217 years. Over time, stands shifted from competition-driven convergence to environment-driven divergence, in which variability among stands was maintained or increased. The relative importance of drivers of stand structural variability differed between density and basal area and among species due to differential species traits, growth rates, and sensitivity to intraspecific competition versus abiotic conditions. Understanding dynamics of postfire stand development is increasingly important for anticipating future landscape patterns as fire activity increases.
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Affiliation(s)
- Kristin H. Braziunas
- Department of Integrative Biology, University of Wisconsin-Madison, Birge Hall, 430 Lincoln Drive, Madison, WI 53706, United States
| | - Winslow D. Hansen
- Department of Integrative Biology, University of Wisconsin-Madison, Birge Hall, 430 Lincoln Drive, Madison, WI 53706, United States
| | - Rupert Seidl
- Institute of Silviculture, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences (BOKU) Vienna, Peter Jordan Strasse 82, 1190 Wien, Austria
| | - Werner Rammer
- Institute of Silviculture, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences (BOKU) Vienna, Peter Jordan Strasse 82, 1190 Wien, Austria
| | - Monica G. Turner
- Department of Integrative Biology, University of Wisconsin-Madison, Birge Hall, 430 Lincoln Drive, Madison, WI 53706, United States
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19
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Kral K, Limb R, Ganguli A, Hovick T, Sedivec K. Seasonal prescribed fire variation decreases inhibitory ability of Poa pratensis L. and promotes native plant diversity. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 223:908-916. [PMID: 30005416 DOI: 10.1016/j.jenvman.2018.06.096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 06/26/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
Global biodiversity is threatened by invasive plant species. Without a thorough understanding of effective management strategies, minimizing their impacts while improving native species diversity will be challenging. Burning in fire-prone landscapes has been successful for managing invasive species and increasing native biodiversity, but it is unclear how specific fire regimes improve restoration practices in novel ecosystems where invasive plants have a similar growth phenology to native plants. We investigated fire as a restoration practice in the Northern Great Plains to decrease the cover of Kentucky bluegrass Poa pratensis (bluegrass), a perennial cool-season invasive grass phenologically similar to dominant native cool-season grasses, by 1) evaluating season of burn (early-growing season, late-growing season, and dormant season) in a field experiment to test differences in plant community composition and 2) manipulating fine fuels (3000-5000 kg ha-1) in an experimental approach to determine the effects of fire on plant survivability of selected native grasses and bluegrass. Bluegrass cover decreased 27% on all field burned plots the first year post-fire. Three years post-fire, late-growing season and dormant season treatments had 35% less bluegrass, whereas the early-growing season treatment was not significantly different from the control. Overall, fire altered the native plant community, with native plants more associated with burned plots. However, native plant community changes were only evident three years post-fire in late-growing season and dormant season burn treatments. In the experimental approach, native grasses and bluegrass experienced high rates of mortality (40-50%) at fuel loads above 4000 kg ha-1 and heat dosages above 30,000 °C·sec, features commonly associated with early-growing season burns. Therefore, early-growing season burns meant to reduce bluegrass may also impact native plants dominant in the region. Invasive species management is complicated in novel ecosystems when invasive plants have similar growth phenologies to native species. Control efforts should consider how different management strategies impact invasive and native plants alike. We found that late-growing season and dormant season burns, along with higher fuel loads, decreased bluegrass cover. Determining mechanisms of control in fire-prone landscapes is a crucial step to improving invasive plant control and increasing native biodiversity.
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Affiliation(s)
- Katherine Kral
- Range Science Program, North Dakota State University, USA.
| | - Ryan Limb
- Range Science Program, North Dakota State University, USA.
| | - Amy Ganguli
- Department of Animal and Range Sciences, New Mexico State University, USA.
| | - Torre Hovick
- Range Science Program, North Dakota State University, USA.
| | - Kevin Sedivec
- Range Science Program, North Dakota State University, USA.
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20
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Wilcox BP, Birt A, Archer SR, Fuhlendorf SD, Kreuter UP, Sorice MG, van Leeuwen WJD, Zou CB. Viewing Woody-Plant Encroachment through a Social–Ecological Lens. Bioscience 2018. [DOI: 10.1093/biosci/biy051] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Bradford P Wilcox
- Department of Ecosystem Science and Management at Texas A&M University, in College Station
| | - Andrew Birt
- Department of Ecosystem Science and Management at Texas A&M University, in College Station
| | - Steven R Archer
- School of Natural Resources and the Environment at the University of Arizona, in Tucson
| | - Samuel D Fuhlendorf
- Department of Natural Resource Management at Oklahoma State University, in Stillwater
| | - Urs P Kreuter
- Department of Ecosystem Science and Management at Texas A&M University, in College Station
| | - Michael G Sorice
- Department of Forest Resources and Environmental Conservation at Virginia Tech, in Blacksburg
| | | | - Chris B Zou
- Department of Natural Resource Management at Oklahoma State University, in Stillwater
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21
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Hansen WD, Braziunas KH, Rammer W, Seidl R, Turner MG. It takes a few to tango: changing climate and fire regimes can cause regeneration failure of two subalpine conifers. Ecology 2018; 99:966-977. [DOI: 10.1002/ecy.2181] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/22/2018] [Accepted: 01/25/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Winslow D. Hansen
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Kristin H. Braziunas
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
| | - Werner Rammer
- Department of Forest and Soil Sciences Institute of Silviculture University of Natural Resources and Life Sciences (BOKU) Vienna Austria
| | - Rupert Seidl
- Department of Forest and Soil Sciences Institute of Silviculture University of Natural Resources and Life Sciences (BOKU) Vienna Austria
| | - Monica G. Turner
- Department of Integrative Biology University of Wisconsin‐Madison Madison Wisconsin 53706 USA
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22
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Abstract
Recent studies have interpreted patterns of remotely sensed tree cover as evidence that forest with intermediate tree cover might be unstable in the tropics, as it will tip into either a closed forest or a more open savanna state. Here we show that across all continents the frequency of wildfires rises sharply as tree cover falls below ~40%. Using a simple empirical model, we hypothesize that the steepness of this pattern causes intermediate tree cover (30‒60%) to be unstable for a broad range of assumptions on tree growth and fire-driven mortality. We show that across all continents, observed frequency distributions of tropical tree cover are consistent with this hypothesis. We argue that percolation of fire through an open landscape may explain the remarkably universal rise of fire frequency around a critical tree cover, but we show that simple percolation models cannot predict the actual threshold quantitatively. The fire-driven instability of intermediate states implies that tree cover will not change smoothly with climate or other stressors and shifts between closed forest and a state of low tree cover will likely tend to be relatively sharp and difficult to reverse.
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23
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Bowman DMJS, Perry GLW, Higgins SI, Johnson CN, Fuhlendorf SD, Murphy BP. Pyrodiversity is the coupling of biodiversity and fire regimes in food webs. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0169. [PMID: 27216526 PMCID: PMC4874407 DOI: 10.1098/rstb.2015.0169] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2016] [Indexed: 11/12/2022] Open
Abstract
Fire positively and negatively affects food webs across all trophic levels and guilds and influences a range of ecological processes that reinforce fire regimes, such as nutrient cycling and soil development, plant regeneration and growth, plant community assembly and dynamics, herbivory and predation. Thus we argue that rather than merely describing spatio-temporal patterns of fire regimes, pyrodiversity must be understood in terms of feedbacks between fire regimes, biodiversity and ecological processes. Humans shape pyrodiversity both directly, by manipulating the intensity, severity, frequency and extent of fires, and indirectly, by influencing the abundance and distribution of various trophic guilds through hunting and husbandry of animals, and introduction and cultivation of plant species. Conceptualizing landscape fire as deeply embedded in food webs suggests that the restoration of degraded ecosystems requires the simultaneous careful management of fire regimes and native and invasive plants and animals, and may include introducing new vertebrates to compensate for extinctions that occurred in the recent and more distant past. This article is part of the themed issue ‘The interaction of fire and mankind’.
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Affiliation(s)
- David M J S Bowman
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania, Australia
| | - George L W Perry
- School of Environment, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Steve I Higgins
- Department of Botany, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Chris N Johnson
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania, Australia
| | - Samuel D Fuhlendorf
- Natural Resource Ecology and Management, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Brett P Murphy
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
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24
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Morales NS, Perry GL. A spatial simulation model to explore the long-term dynamics of podocarp-tawa forest fragments, northern New Zealand. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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25
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Ondei S, Prior LD, Williamson GJ, Vigilante T, Bowman DMJS. Water, land, fire, and forest: Multi-scale determinants of rainforests in the Australian monsoon tropics. Ecol Evol 2017; 7:1592-1604. [PMID: 28261468 PMCID: PMC5330914 DOI: 10.1002/ece3.2734] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 11/22/2016] [Accepted: 12/18/2016] [Indexed: 11/06/2022] Open
Abstract
The small rainforest fragments found in savanna landscapes are powerful, yet often overlooked, model systems to understand the controls of these contrasting ecosystems. We analyzed the relative effect of climatic variables on rainforest density at a subcontinental level, and employed high-resolution, regional-level analyses to assess the importance of landscape settings and fire activity in determining rainforest density in a frequently burnt Australian savanna landscape. Estimates of rainforest density (ha/km2) across the Northern Territory and Western Australia, derived from preexisting maps, were used to calculate the correlations between rainforest density and climatic variables. A detailed map of the northern Kimberley (Western Australia) rainforests was generated and analyzed to determine the importance of geology and topography in controlling rainforests, and to contrast rainforest density on frequently burnt mainland and nearby islands. In the northwestern Australian, tropics rainforest density was positively correlated with rainfall and moisture index, and negatively correlated with potential evapotranspiration. At a regional scale, rainforests showed preference for complex topographic positions and more fertile geology. Compared with mainland areas, islands had significantly lower fire activity, with no differences between terrain types. They also displayed substantially higher rainforest density, even on level terrain where geomorphological processes do not concentrate nutrients or water. Our multi-scale approach corroborates previous studies that suggest moist climate, infrequent fires, and geology are important stabilizing factors that allow rainforest fragments to persist in savanna landscapes. These factors need to be incorporated in models to predict the future extent of savannas and rainforests under climate change.
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Affiliation(s)
- Stefania Ondei
- School of Biological Sciences University of Tasmania Sandy Bay Tas. Australia
| | - Lynda D Prior
- School of Biological Sciences University of Tasmania Sandy Bay Tas. Australia
| | - Grant J Williamson
- School of Biological Sciences University of Tasmania Sandy Bay Tas. Australia
| | - Tom Vigilante
- Wunambal Gaambera Aboriginal Corporation Kalumburu WA Australia; Bush Heritage Australia Melbourne Vic. Australia
| | - David M J S Bowman
- School of Biological Sciences University of Tasmania Sandy Bay Tas. Australia
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26
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Spatial variability in tree regeneration after wildfire delays and dampens future bark beetle outbreaks. Proc Natl Acad Sci U S A 2016; 113:13075-13080. [PMID: 27821739 DOI: 10.1073/pnas.1615263113] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Climate change is altering the frequency and severity of forest disturbances such as wildfires and bark beetle outbreaks, thereby increasing the potential for sequential disturbances to interact. Interactions can amplify or dampen disturbances, yet the direction and magnitude of future disturbance interactions are difficult to anticipate because underlying mechanisms remain poorly understood. We tested how variability in postfire forest development affects future susceptibility to bark beetle outbreaks, focusing on mountain pine beetle (Dendroctonus ponderosae) and Douglas-fir beetle (Dendroctonus pseudotsugae) in forests regenerating from the large high-severity fires that affected Yellowstone National Park in Wyoming in 1988. We combined extensive field data on postfire tree regeneration with a well-tested simulation model to assess susceptibility to bark beetle outbreaks over 130 y of stand development. Despite originating from the same fire event, among-stand variation in forest structure was very high and remained considerable for over a century. Thus, simulated emergence of stands susceptible to bark beetles was not temporally synchronized but was protracted by several decades, compared with stand development from spatially homogeneous regeneration. Furthermore, because of fire-mediated variability in forest structure, the habitat connectivity required to support broad-scale outbreaks and amplifying cross-scale feedbacks did not develop until well into the second century after the initial burn. We conclude that variability in tree regeneration after disturbance can dampen and delay future disturbance by breaking spatiotemporal synchrony on the landscape. This highlights the importance of fostering landscape variability in the context of ecosystem management given changing disturbance regimes.
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27
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Perry GLW, Wainwright J, Etherington TR, Wilmshurst JM. Experimental Simulation: Using Generative Modeling and Palaeoecological Data to Understand Human-Environment Interactions. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00109] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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28
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Wood SW, Ward C, Bowman DMJS. Substrate controls growth rates of the woody pioneer
Leptospermum lanigerum
colonizing montane grasslands in northern Tasmania. AUSTRAL ECOL 2016. [DOI: 10.1111/aec.12390] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sam W. Wood
- School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tasmania 7000 Australia
| | - Carly Ward
- School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tasmania 7000 Australia
| | - David M. J. S. Bowman
- School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tasmania 7000 Australia
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29
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Zylstra P, Bradstock RA, Bedward M, Penman TD, Doherty MD, Weber RO, Gill AM, Cary GJ. Biophysical Mechanistic Modelling Quantifies the Effects of Plant Traits on Fire Severity: Species, Not Surface Fuel Loads, Determine Flame Dimensions in Eucalypt Forests. PLoS One 2016; 11:e0160715. [PMID: 27529789 PMCID: PMC4986950 DOI: 10.1371/journal.pone.0160715] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/22/2016] [Indexed: 11/18/2022] Open
Abstract
The influence of plant traits on forest fire behaviour has evolutionary, ecological and management implications, but is poorly understood and frequently discounted. We use a process model to quantify that influence and provide validation in a diverse range of eucalypt forests burnt under varying conditions. Measured height of consumption was compared to heights predicted using a surface fuel fire behaviour model, then key aspects of our model were sequentially added to this with and without species-specific information. Our fully specified model had a mean absolute error 3.8 times smaller than the otherwise identical surface fuel model (p < 0.01), and correctly predicted the height of larger (≥1 m) flames 12 times more often (p < 0.001). We conclude that the primary endogenous drivers of fire severity are the species of plants present rather than the surface fuel load, and demonstrate the accuracy and versatility of the model for quantifying this.
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Affiliation(s)
- Philip Zylstra
- Centre for Environmental Risk Management of Bushfires, Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- * E-mail:
| | - Ross A. Bradstock
- Centre for Environmental Risk Management of Bushfires, Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Michael Bedward
- Centre for Environmental Risk Management of Bushfires, Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Trent D. Penman
- School of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, VIC, Australia
| | - Michael D. Doherty
- Fenner School of Environment and Society, Australian National University, Acton, ACT, Australia
| | - Rodney O. Weber
- Physical, Environmental and Mathematical Sciences, University of NSW ADFA, Canberra, ACT, Australia
| | - A. Malcolm Gill
- Fenner School of Environment and Society, Australian National University, Acton, ACT, Australia
| | - Geoffrey J. Cary
- Fenner School of Environment and Society, Australian National University, Acton, ACT, Australia
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Staal A, Dekker SC, Xu C, van Nes EH. Bistability, Spatial Interaction, and the Distribution of Tropical Forests and Savannas. Ecosystems 2016. [DOI: 10.1007/s10021-016-0011-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Connell SD, Ghedini G. Resisting regime-shifts: the stabilising effect of compensatory processes. Trends Ecol Evol 2015; 30:513-5. [PMID: 26190138 DOI: 10.1016/j.tree.2015.06.014] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/26/2015] [Accepted: 06/26/2015] [Indexed: 10/23/2022]
Abstract
Ecologists seem predisposed to studying change because we are intuitively interested in dynamic systems, including their vulnerability to human disturbance. We contrast this disposition with the value of studying processes that work against change. Although powerful, processes that counter disturbance often go unexplored because they yield no observable community change. This stability results from compensatory processes which are initiated by disturbance; these adjust in proportion to the strength of the disturbance to prevent community change. By recognising such buffering processes, we might also learn to recognise the early warning signals of community shifts which are notoriously difficult to predict because communities often show little to no change before their tipping point is reached.
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Affiliation(s)
- Sean D Connell
- Southern Seas Ecology Laboratories, School of Biological Sciences and The Environment Institute, The University of Adelaide, Adelaide, 5005 SA, Australia.
| | - Giulia Ghedini
- Southern Seas Ecology Laboratories, School of Biological Sciences and The Environment Institute, The University of Adelaide, Adelaide, 5005 SA, Australia
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Perry GLW, Wilmshurst JM, Ogden J, Enright NJ. Exotic Mammals and Invasive Plants Alter Fire-Related Thresholds in Southern Temperate Forested Landscapes. Ecosystems 2015. [DOI: 10.1007/s10021-015-9898-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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