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Rosenfield MF, Jakovac CC, Vieira DLM, Poorter L, Brancalion PHS, Vieira ICG, de Almeida DRA, Massoca P, Schietti J, Albernaz ALM, Ferreira MJ, Mesquita RCG. Ecological integrity of tropical secondary forests: concepts and indicators. Biol Rev Camb Philos Soc 2023; 98:662-676. [PMID: 36453621 DOI: 10.1111/brv.12924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022]
Abstract
Naturally regenerating forests or secondary forests (SFs) are a promising strategy for restoring large expanses of tropical forests at low cost and with high environmental benefits. This expectation is supported by the high resilience of tropical forests after natural disturbances, yet this resilience can be severely reduced by human impacts. Assessing the characteristics of SFs and their ecological integrity (EI) is essential to evaluating their role for conservation, restoration, and provisioning of ecosystem services. In this study, we aim to propose a concept and indicators that allow the assessment and classification of the EI of SFs. To this end, we review the literature to assess how EI has been addressed in different ecosystems and which indicators of EI are most commonly used for tropical forests. Building upon this knowledge we propose a modification of the concept of EI to embrace SFs and suggest indicators of EI that can be applied to different successional stages or stand ages. Additionally, we relate these indicators to ecosystem service provision in order to support the practical application of the theory. EI is generally defined as the ability of ecosystems to support and maintain composition, structure and function similar to the reference conditions of an undisturbed ecosystem. This definition does not consider the temporal dynamics of recovering ecosystems, such as SFs. Therefore, we suggest incorporation of an optimal successional trajectory as a reference in addition to the old-growth forest reference. The optimal successional trajectory represents the maximum EI that can be attained at each successional stage in a given region and enables the evaluation of EI at any given age class. We further suggest a list of indicators, the main ones being: compositional indicators (species diversity/richness and indicator species); structural indicators (basal area, heterogeneity of basal area and canopy cover); function indicators (tree growth and mortality); and landscape proxies (landscape heterogeneity, landscape connectivity). Finally, we discuss how this approach can assist in defining the value of SF patches to provide ecosystem services, restore forests and contribute to ecosystem conservation.
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Affiliation(s)
- Milena F Rosenfield
- Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo, 2936, Manaus, AM, 69083-000, Brazil
| | - Catarina C Jakovac
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
- Centro de Ciências Agrárias, Universidade Federal de Santa Catarina (UFSC), Rod. Admar Gonzaga, 1346, Itacorubi, Florianópolis, SC, 88034-000, Brazil
| | - Daniel L M Vieira
- Embrapa Recursos Genéticos e Biotecnologia, Empresa Brasileira de Pesquisa Agropecuária (Embrapa), Av. W5 Norte (final), Brasília, DF, 70770917, Brazil
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Pedro H S Brancalion
- Departamento de Ciências Florestais, Escola Superior de Agricultura Luiz de Queiroz (ESALQ), Universidade de São Paulo (USP), Av. Pádua Dias, 11, Piracicaba, SP, 13418-900, Brazil
| | - Ima C G Vieira
- Coordenação de Botânica, Museu Paraense Emílio Goeldi, Av. Magalhães Barata, 376, Belém, PA, 66040-170, Brazil
| | - Danilo R A de Almeida
- Departamento de Ciências Florestais, Escola Superior de Agricultura Luiz de Queiroz (ESALQ), Universidade de São Paulo (USP), Av. Pádua Dias, 11, Piracicaba, SP, 13418-900, Brazil
| | - Paulo Massoca
- Center for the Analysis of Social-Ecological Landscapes (CASEL), Indiana University, Student Building 331, 701 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Juliana Schietti
- Departamento de Biologia, Instituto de Ciências Biológicas, Universidade Federal do Amazonas (UFAM), Av. General Rodrigo Octavio Jordão Ramos, 1200, Coroado I, Manaus, AM, 69067-005, Brazil
| | - Ana Luisa M Albernaz
- Coordenação de Ciências da Terra e Ecologia, Museu Paraense Emílio Goeldi, Av. Magalhães Barata, 376, Belém, PA, 66040-170, Brazil
| | - Marciel J Ferreira
- Departamento de Ciências Florestais, Universidade Federal do Amazonas (UFAM), Av. General Rodrigo Octávio Jordão Ramos, 3000, Manaus, AM, 69080-900, Brazil
| | - Rita C G Mesquita
- Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo, 2936, Manaus, AM, 69083-000, Brazil
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Barber C, Graves SJ, Hall JS, Zuidema PA, Brandt J, Bohlman SA, Asner GP, Bailón M, Caughlin TT. Species-level tree crown maps improve predictions of tree recruit abundance in a tropical landscape. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2585. [PMID: 35333420 DOI: 10.1002/eap.2585] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 10/26/2021] [Accepted: 11/04/2021] [Indexed: 06/14/2023]
Abstract
Predicting forest recovery at landscape scales will aid forest restoration efforts. The first step in successful forest recovery is tree recruitment. Forecasts of tree recruit abundance, derived from the landscape-scale distribution of seed sources (i.e., adult trees), could assist efforts to identify sites with high potential for natural regeneration. However, previous work revealed wide variation in the effect of seed sources on seedling abundance, from positive to no effect. We quantified the relationship between adult tree seed sources and tree recruits and predicted where natural recruitment would occur in a fragmented, tropical, agricultural landscape. We integrated species-specific tree crown maps generated from hyperspectral imagery and property ownership data with field data on the spatial distribution of tree recruits from five species. We then developed hierarchical Bayesian models to predict landscape-scale recruit abundance. Our models revealed that species-specific maps of tree crowns improved recruit abundance predictions. Conspecific crown area had a much stronger impact on recruitment abundance (8.00% increase in recruit abundance when conspecific tree density increases from zero to one tree; 95% credible interval (CI): 0.80% to 11.57%) than heterospecific crown area (0.03% increase with the addition of a single heterospecific tree, 95% CI: -0.60% to 0.68%). Individual property ownership was also an important predictor of recruit abundance: The best performing model had varying effects of conspecific and heterospecific crown area on recruit abundance, depending on individual property ownership. We demonstrate how novel remote sensing approaches and cadastral data can be used to generate high-resolution and landscape-level maps of tree recruit abundance. Spatial models parameterized with field, cadastral, and remote sensing data are poised to assist decision support for forest landscape restoration.
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Affiliation(s)
- Cristina Barber
- Biological Sciences, Boise State University, Boise, Idaho, USA
| | - Sarah J Graves
- Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jefferson S Hall
- Smithsonian Tropical Research Institute, ForestGEO, Panama City, Panama
| | - Pieter A Zuidema
- Forest Ecology and Forest Management group, Wageningen University, Wageningen, The Netherlands
| | - Jodi Brandt
- Human-Environment Systems, Boise State University, Boise, Idaho, USA
| | - Stephanie A Bohlman
- School of Forest Resources and Conservation, University of Florida, Gainesville, Florida, USA
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Gregory P Asner
- Center for Global Discovery and Conservation Science, Arizona State University, Tempe, Arizona, USA
| | - Mario Bailón
- Smithsonian Tropical Research Institute, Panama City, Panama
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Membang G, Ambang Z, Mahot HC, Kuate AF, Fiaboe KKM, Hanna R. Thermal response and horizontal transmission of cameroonian isolates of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae – Candidates for microbial controls of the banana root borer Cosmopolites sordidus. FUNGAL ECOL 2021. [DOI: 10.1016/j.funeco.2021.101042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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4
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Tize I, Fotso AK, Nukenine EN, Masso C, Ngome FA, Suh C, Lendzemo VW, Nchoutnji I, Manga G, Parkes E, Kulakow P, Kouebou C, Fiaboe KKM, Hanna R. New cassava germplasm for food and nutritional security in Central Africa. Sci Rep 2021; 11:7394. [PMID: 33795808 PMCID: PMC8016988 DOI: 10.1038/s41598-021-86958-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/22/2021] [Indexed: 11/08/2022] Open
Abstract
Cassava is a key food security crop in Central Africa, but its production depends largely on the use of local farmers' varieties characterized by inherently low yield which is compounded by generally high susceptibility to various growth and yield-limiting pests and diseases. Improved cassava genotypes have demonstrated the potential to substantially improve cassava's contribution to food security and the development of the cassava industry and the improvement of nutrition status elsewhere in Western Africa. Eleven improved cassava genotypes were compared with a local landrace (LMR) used as a check under field conditions over two years in eight locations, grouped in four agro-ecologies in Cameroon. Pest and disease abundance/incidence and damage severity were evaluated. At harvest, root yield and carotenoid content were measured. Best linear unbiased predictors showed the lowest breeding value for LMR with the cassava mosaic virus disease (+ 66.40 ± 2.42) compared with 1.00 ± 0.02% for the most susceptible improved genotype. Two genotypes (I010040-27 and I011797) stood out for having higher predicted fresh root yield means which were at least 16 times greater compared with LMR. Predicted total carotenoid content was the highest (+ 5.04 ± 0.17) for improved genotype I070593 compared with LMR which showed the lowest (- 3.90 ± 0.06%) and could contribute to the alleviation of vitamin A deficiency from cassava-based food systems. Diffusion of high-yielding and nutritious genotypes could alleviate food and nutritional security in Central Africa.
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Affiliation(s)
- Isaac Tize
- International Institute of Tropical Agriculture, BP 2008, Messa, Yaoundé, Cameroon
- Department of Biological Sciences, University of Ngaoundere, BP 454, Ngaoundere, Cameroon
| | - Apollin Kuate Fotso
- International Institute of Tropical Agriculture, BP 2008, Messa, Yaoundé, Cameroon.
| | - Elias Nchiwan Nukenine
- Department of Biological Sciences, University of Ngaoundere, BP 454, Ngaoundere, Cameroon
| | - Cargele Masso
- International Institute of Tropical Agriculture, BP 2008, Messa, Yaoundé, Cameroon
| | | | - Christopher Suh
- Institute of Agricultural Research for Development, BP 2067, Yaoundé, Cameroon
| | | | - Ibrahim Nchoutnji
- Institute of Agricultural Research for Development, BP 2067, Yaoundé, Cameroon
| | - Gabriel Manga
- Institute of Agricultural Research for Development, BP 2067, Yaoundé, Cameroon
| | - Elisabeth Parkes
- International Institute of Tropical Agriculture, PMB 320 Oyo Road, Ibadan, Nigeria
| | - Peter Kulakow
- International Institute of Tropical Agriculture, PMB 320 Oyo Road, Ibadan, Nigeria
| | - Christiant Kouebou
- Agricultural Investment and Market Development Project, Yaoundé, Cameroon
| | - Komi K M Fiaboe
- International Institute of Tropical Agriculture, BP 2008, Messa, Yaoundé, Cameroon
| | - Rachid Hanna
- International Institute of Tropical Agriculture, BP 2008, Messa, Yaoundé, Cameroon
- Congo Basin Institute, Institute of Environment and Sustainability, University of California, Box 951496, Los Angeles, USA
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5
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Jakovac CC, Junqueira AB, Crouzeilles R, Peña-Claros M, Mesquita RCG, Bongers F. The role of land-use history in driving successional pathways and its implications for the restoration of tropical forests. Biol Rev Camb Philos Soc 2021; 96:1114-1134. [PMID: 33709566 PMCID: PMC8360101 DOI: 10.1111/brv.12694] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 01/29/2023]
Abstract
Secondary forests are increasingly important components of human‐modified landscapes in the tropics. Successional pathways, however, can vary enormously across and within landscapes, with divergent regrowth rates, vegetation structure and species composition. While climatic and edaphic conditions drive variations across regions, land‐use history plays a central role in driving alternative successional pathways within human‐modified landscapes. How land use affects succession depends on its intensity, spatial extent, frequency, duration and management practices, and is mediated by a complex combination of mechanisms acting on different ecosystem components and at different spatial and temporal scales. We review the literature aiming to provide a comprehensive understanding of the mechanisms underlying the long‐lasting effects of land use on tropical forest succession and to discuss its implications for forest restoration. We organize it following a framework based on the hierarchical model of succession and ecological filtering theory. This review shows that our knowledge is mostly derived from studies in Neotropical forests regenerating after abandonment of shifting cultivation or pasture systems. Vegetation is the ecological component assessed most often. Little is known regarding how the recovery of belowground processes and microbiota communities is affected by previous land‐use history. In published studies, land‐use history has been mostly characterized by type, without discrimination of intensity, extent, duration or frequency. We compile and discuss the metrics used to describe land‐use history, aiming to facilitate future studies. The literature shows that (i) species availability to succession is affected by transformations in the landscape that affect dispersal, and by management practices and seed predation, which affect the composition and diversity of propagules on site. Once a species successfully reaches an abandoned field, its establishment and performance are dependent on resistance to management practices, tolerance to (modified) soil conditions, herbivory, competition with weeds and invasive species, and facilitation by remnant trees. (ii) Structural and compositional divergences at early stages of succession remain for decades, suggesting that early communities play an important role in governing further ecosystem functioning and processes during succession. Management interventions at early stages could help enhance recovery rates and manipulate successional pathways. (iii) The combination of local and landscape conditions defines the limitations to succession and therefore the potential for natural regeneration to restore ecosystem properties effectively. The knowledge summarized here could enable the identification of conditions in which natural regeneration could efficiently promote forest restoration, and where specific management practices are required to foster succession. Finally, characterization of the landscape context and previous land‐use history is essential to understand the limitations to succession and therefore to define cost‐effective restoration strategies. Advancing knowledge on these two aspects is key for finding generalizable relations that will increase the predictability of succession and the efficiency of forest restoration under different landscape contexts.
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Affiliation(s)
- Catarina C Jakovac
- International Institute for Sustainability, Estrada Dona Castorina, 124, Rio de Janeiro, 22460-320, Brazil.,Forest Ecology and Management Group, Wageningen University & Research, Wageningen, 6700 AA, The Netherlands
| | - André B Junqueira
- International Institute for Sustainability, Estrada Dona Castorina, 124, Rio de Janeiro, 22460-320, Brazil.,Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, Carrer de les Columnes s/n, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Renato Crouzeilles
- International Institute for Sustainability, Estrada Dona Castorina, 124, Rio de Janeiro, 22460-320, Brazil.,International Institute for Sustainability Australia, Canberra, ACT, 2602, Australia.,Mestrado Profissional em Ciências do Meio Ambiente, Universidade Veiga de Almeida, Rio de Janeiro, 20271-901, Brazil
| | - Marielos Peña-Claros
- Forest Ecology and Management Group, Wageningen University & Research, Wageningen, 6700 AA, The Netherlands
| | - Rita C G Mesquita
- Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Manaus, 69083-000, Brazil
| | - Frans Bongers
- Forest Ecology and Management Group, Wageningen University & Research, Wageningen, 6700 AA, The Netherlands
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6
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Exploring Livelihood Strategies of Shifting Cultivation Farmers in Assam through Games. SUSTAINABILITY 2020. [DOI: 10.3390/su12062438] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding landscape change starts with understanding what motivates farmers to transition away from one system, shifting cultivation, into another, like plantation crops. Here we explored the resource allocation strategies of the farmers of the Karbi tribe in Northeast India, who practice a traditional shifting cultivation system called jhum. Through a participatory modelling framework, we co-developed a role-playing game of the local farming system. In the game, farmers allocated labour and cash to meet household needs, while also investing in new opportunities like bamboo, rubber and tea, or the chance to improve their living standards. Farmers did embrace new options where investment costs, especially monetary investments, are low. Returns on these investments were not automatically re-invested in further long-term, more expensive and promising opportunities. Instead, most of the money is spend on improving household living standards, particularly the next generation’s education. The landscape changed profoundly based on the farmers’ strategies. Natural ecological succession was replaced by an improved fallow of marketable bamboo species. Plantations of tea and rubber became more prevalent as time progressed while old practices ensuring food security were not yet given up.
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Moonen PCJ, Verbist B, Boyemba Bosela F, Norgrove L, Dondeyne S, Van Meerbeek K, Kearsley E, Verbeeck H, Vermeir P, Boeckx P, Muys B. Disentangling how management affects biomass stock and productivity of tropical secondary forests fallows. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 659:101-114. [PMID: 30597460 DOI: 10.1016/j.scitotenv.2018.12.138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 12/08/2018] [Accepted: 12/09/2018] [Indexed: 06/09/2023]
Abstract
A better understanding of biomass production in secondary forests after cultivation is essential for assessing the resilience of slash and burn systems and their capacity to deliver ecosystem services. Biomass production is influenced by management legacies, landscape configuration and soil, but these drivers are rarely studied simultaneously, nor is the role of changes in vegetation properties in linking them to biomass production. We assessed how management legacies affect biomass in secondary forests created by slash and burn in the central Congo Basin, and tested whether changes in productivity could be attributed to changes in stem density, functional diversity, functional identity or soil. Using data from 6452 trees in 96 fallow plots nested in 3 study sites, we looked for the main determinants of aboveground biomass (AGB) of woody vegetation in fallow systems. Next, using a subset of 58 plots in fallow fields aged 5 to 10 years, we used confirmatory path analysis to explore the relations between management history, soil, vegetation properties and biomass productivity. The sampled fallow fields had, on average, 58.4 (±46.2) Mg ha-1 AGB. AGB was positively related to both fallow age and to the proportion of remnant trees in AGB and negatively related to the number of previous cultivation cycles. Biomass productivity varied with the number of previous slash-and-burn cycles, with notable declines in the fourth cycle. The effect of management history was mainly through a reduction in the dominance of fast growing tree species and in the number of regenerating stems, which were also indirectly affected by an increase in C. odorata cover. Soil fertility status and the biomass of remnant trees also modified biomass productivity. Our findings suggest that under the current management intensity the capacity of the slash and burn system to provide important ecosystem functions, such as carbon sequestration, is declining.
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Affiliation(s)
- Pieter C J Moonen
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Belgium.
| | - Bruno Verbist
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Belgium
| | | | - Lindsey Norgrove
- School of Agricultural, Forest and Food Sciences, Bern University of Applied Sciences, Switzerland
| | - Stefaan Dondeyne
- Division of Soil and Water, Department of Earth and Environmental Sciences, KU Leuven, Belgium
| | - Koenraad Van Meerbeek
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Belgium; Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Aarhus University, Ny Munkegade 114, 8000 Aarhus C, Denmark; Section for Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, Ny Munkegade 114, 8000 Aarhus, C, Denmark
| | - Elizabeth Kearsley
- CAVElab - Computational and Applied Vegetation Ecology, Department of Applied Ecology and Environmental Biology, Ghent University, Belgium
| | - Hans Verbeeck
- CAVElab - Computational and Applied Vegetation Ecology, Department of Applied Ecology and Environmental Biology, Ghent University, Belgium
| | - Pieter Vermeir
- Laboratory of Chemical Analyses-LCA, Department of Green Chemistry and Technology, Ghent University, Belgium
| | - Pascal Boeckx
- Isotope Bioscience Laboratory - ISOFYS, Ghent University, Belgium
| | - Bart Muys
- Division of Forest, Nature and Landscape, Department of Earth and Environmental Sciences, KU Leuven, Belgium
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Rahman SA, Sunderland T, Roshetko JM, Healey JR. Facilitating smallholder tree farming in fragmented tropical landscapes: Challenges and potentials for sustainable land management. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 198:110-121. [PMID: 28453986 DOI: 10.1016/j.jenvman.2017.04.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 04/11/2017] [Accepted: 04/14/2017] [Indexed: 06/07/2023]
Abstract
Under changing land use in tropical Asia, there is evidence of forest product diversification through implementation of tree-based farming by smallholders. This paper assesses in two locations, West Java, Indonesia and eastern Bangladesh, current land use conditions from the perspective of smallholder farmers, the factors that facilitate their adoption of tree farming, and the potential of landscape-scale approaches to foster sustainable land management. Data were collected through rapid rural appraisals, focus group discussions, field observations, semi-structured interviews of farm households and key informant interviews of state agricultural officers. Land at both study sites is typically fragmented due to conversion of forest to agriculture and community settlement. Local land use challenges are associated with pressures of population increase, poverty, deforestation, shortage of forest products, lack of community-scale management, weak tenure, underdeveloped markets, government decision-making with insufficient involvement of local people, and poor extension services. Despite these challenges, smallholder tree farming is found to be successful from farmers' perspectives. However, constraints of local food crop cultivation traditions, insecure land tenure, lack of capital, lack of knowledge, lack of technical assistance, and perceived risk of investing in land due to local conflict (in Bangladesh) limit farmers' willingness to adopt this land use alternative. Overcoming these barriers to adoption will require management at a landscape scale, including elements of both segregation and integration of land uses, supported by competent government policies and local communities having sufficiently high social capital.
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Affiliation(s)
- Syed Ajijur Rahman
- Department of Food and Resource Economics, Section of Environment and Natural Resources, University of Copenhagen, 1958, Frederiksberg, Denmark; School of Environment, Natural Resources and Geography, Bangor University, Bangor, LL57 2UW, United Kingdom; Center for International Forestry Research (CIFOR), Bogor, West Java, 16115, Indonesia.
| | - Terry Sunderland
- Center for International Forestry Research (CIFOR), Bogor, West Java, 16115, Indonesia
| | - James M Roshetko
- World Agroforestry Centre (ICRAF), Bogor, West Java, 16115, Indonesia
| | - John Robert Healey
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, LL57 2UW, United Kingdom
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Wood SLR, Rhemtulla JM, Coomes OT. Cropping history trumps fallow duration in long-term soil and vegetation dynamics of shifting cultivation systems. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:519-531. [PMID: 27770604 DOI: 10.1002/eap.1462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 08/23/2016] [Accepted: 09/08/2016] [Indexed: 06/06/2023]
Abstract
In the study of shifting cultivation systems, fallow duration is seen as the key determinant of vegetation and soil dynamics: long fallows renew soil fertility, biomass, and biodiversity. However, long fallow systems are increasingly replaced around the world with short-medium fallow systems, and awareness is growing of the need to look across multiple (not just single) crop-fallow cycles to accurately understand observed soil and vegetation patterns. In a study from Peru that builds on 50+ years of field-level land-use histories, we found that, over multiple crop-fallow cycles, farmers' cropping practices mattered more than fallow duration for biodiversity and soil fertility. After initial clearing of primary forest, a precipitous decline occurred in tree species richness of fallows (>50%) with gradual but continued loss thereafter (~0.5 species/yr), which resulted in shifts in species composition over time. For soils, the decline in fertility was more gradual with each additional cycle of cropping resulting in lowered soil organic matter, available phosphorus, and exchangeable sodium levels, even in fields with long fallow durations. In the most intensively used sites, soils experienced a 16% decline of soil organic matter over 4+ cycles. In contrast to previous studies, biomass accumulation and carbon stocks were not related to cropping history or to the number and duration of cycles observed. This suggests that biodiversity-soils-biomass dynamics may not necessarily "move together" in these systems. These results point to the importance of the number of crop-fallow cycles over fallow duration in driving soil fertility and vegetation dynamics under shifting cultivation in the Peruvian Amazon. Overtime shifting cultivation may erode soil fertility and biodiversity levels even if long fallows persist. As the decline in soils appears slow, it may be possible to address this effect with the use of amendments, however biodiversity declines and species compositional changes may be much harder to reverse.
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Affiliation(s)
- Sylvia L R Wood
- Earth Institute Center for Environmental Sustainability, Columbia University, New York, New York, 10027, USA
- Department of Geography, McGill University, Montreal, Quebec, H3A 0B9, Canada
| | - Jeanine M Rhemtulla
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Oliver T Coomes
- Department of Geography, McGill University, Montreal, Quebec, H3A 0B9, Canada
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10
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Caughlin TT, Elliott S, Lichstein JW. When does seed limitation matter for scaling up reforestation from patches to landscapes? ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:2437-2448. [PMID: 27862619 DOI: 10.1002/eap.1410] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 05/17/2016] [Accepted: 05/25/2016] [Indexed: 06/06/2023]
Abstract
Restoring forest to hundreds of millions of hectares of degraded land has become a centerpiece of international plans to sequester carbon and conserve biodiversity. Forest landscape restoration will require scaling up ecological knowledge of secondary succession from small-scale field studies to predict forest recovery rates in heterogeneous landscapes. However, ecological field studies reveal widely divergent times to forest recovery, in part due to landscape features that are difficult to replicate in empirical studies. Seed rain can determine reforestation rate and depends on landscape features that are beyond the scale of most field studies. We develop mathematical models to quantify how landscape configuration affects seed rain and forest regrowth in degraded patches. The models show how landscape features can alter the successional trajectories of otherwise identical patches, thus providing insight into why some empirical studies reveal a strong effect of seed rain on secondary succession, while others do not. We show that seed rain will strongly limit reforestation rate when patches are near a threshold for arrested succession, when positive feedbacks between tree canopy cover and seed rain occur during early succession, and when directed dispersal leads to between-patch interactions. In contrast, seed rain has weak effects on reforestation rate over a wide range of conditions, including when landscape-scale seed availability is either very high or very low. Our modeling framework incorporates growth and survival parameters that are commonly estimated in field studies of reforestation. We demonstrate how mathematical models can inform forest landscape restoration by allowing land managers to predict where natural regeneration will be sufficient to restore tree cover. Translating quantitative forecasts into spatially targeted interventions for forest landscape restoration could support target goals of restoring millions of hectares of degraded land and help mitigate global climate change.
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Affiliation(s)
- T Trevor Caughlin
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA
| | - Stephen Elliott
- Forest Restoration Research Unit, Department of Biology, Science Faculty, Chiang Mai University Huaykaew Rd, Chiang Mai, 50200, Thailand
| | - Jeremy W Lichstein
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA
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Mesquita RDCG, Massoca PEDS, Jakovac CC, Bentos TV, Williamson GB. Amazon Rain Forest Succession: Stochasticity or Land-Use Legacy? Bioscience 2015. [DOI: 10.1093/biosci/biv108] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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