Ocupação humana e reflexos sobre a cobertura florestal em um assentamento rural na Amazônia central

Rural settlements created to accommodate part of the migrants attracted to the Amazon over the last four decades were included by the Brazilian Environmental Ministry (MMA) among the main responsible for the deforestation in the region in 2008. The impacts of human establishment on the environment are even more dramatic if we consider the degradation process associated to the forest fragmentation and the exploitation of natural resources in the settlements. This work investigated aspects related to the interaction between man and environment in the Uatumã rural settlement project (Projeto de Assentamento Uatumã). The settlement was created in 1987 in Presidente Figueiredo municipality, Amazonas state, Brazil (59o 50’ 14” W and 02o 02’ 24” S). Forests in that region are subjected to logging for about 30 years. We tried to identify aspects concerning the history of its occupation analyzing the relationship between the arrival and establishment of the families at the area and the reflexes on deforestation and forest degradation in its limits. Data about deforestation were obtained from a temporal series of 14 images of the Landsat satellite covering 30 years. This information was related to the data collected through interviews with the settlement dwellers and government agents working at the area, as well as to historic aspects of the development of the region. Data reported in studies of adjacent undisturbed primary forests were utilized for comparison between these variables in order to evaluate forest degradation in the settlement. Being established in a frontier opened by the construction of roadways and the Balbina hydroelectric plant, problems related to soil infertility, economic instability, poor infrastructure and debility of institutional assistance prevented the permanence of many families at their lots. The lumber exploitation that already was established in the region became the main option to those that remained in the area, preventing the total felling of the forest in the settlement. Although there is a great difference between the lots due to the proximity with the roadway that cuts the settlement, the mean forest cover is 80%. The deforestation rates during this period varied in function of local forces favoring the forest conversion and also because of underlying causes occurring in regional, national or global contexts. The exploitation of the forest resources at the settlement reduced the density (476.7 individuals ha -1 , p < 0.001), basal area (23.3 m 2 ha -1 , p < 0.001) and aboveground dry biomass (295.7 Mg ha -1 , p = 0.008) at the study area. A reduction of 12% of aboveground dry biomass was calculated comparing the study area with undisturbed primary forests of the region. Badly planned and managed human settlements within the dense forest of the Amazon open the frontier to dramatic land use changes and exploitation of a vast timber stock, resulting in deforestation and degradation of these ecosystems. Comprehending the subtleties involved in the relationship between man and environment is essential for the development of more interesting and adequate alternatives for the local reality and elaboration of new occupation and development models for the region.Assentamentos rurais criados ao longo das últimas quatro décadas para abrigar parte do contingente populacional atraído para a Amazônia foram relacionados pelo Ministério do Meio Ambiente (MMA) dentre os principais responsáveis por seu desmatamento no ano de 2008. O impacto dessa ocupação humana é mais profundo se considerados os processos de degradação associados à fragmentação florestal e utilização e exploração dos recursos naturais nos assentamentos. Neste trabalho foram investigados aspectos relacionados à interação entre homem e ambiente no Projeto de Assentamento (PA) Uatumã. Criado em 1987 no município de Presidente Figueiredo, Amazonas, Brasil (59o 50’ 14” W e 02o 02’ 24” S), o assentamento está localizado em uma área objeto de exploração madeireira há aproximadamente 30 anos. Procurou-se identificar aspectos referentes à história de sua ocupação, analisando-se a relação entre processos envolvidos com a chegada e o estabelecimento das famílias no local e os reflexos sobre o desmatamento e a degradação florestal em seus limites. Dados sobre o desmatamento foram obtidos de uma série temporal de 14 imagens do satélite Landsat. Essa informação foi relacionada aos dados coletados em entrevistas com moradores e funcionários do governo atuando no local, assim como a aspectos da história de desenvolvimento da região. De inventários florestais conduzidos em 15 propriedades do assentamento foram calculadas a densidade, área basal e biomassa de árvores e lianas nessas florestas. Dados reportados em estudos conduzidos em florestas não alteradas adjacentes foram utilizados para comparação entre essas variáveis e para avaliação da degradação florestal no assentamento. Estabelecido em uma fronteira aberta pelas construções de rodovias e da Usina Hidrelétrica de Balbina, problemas relacionados à infertilidade do solo, instabilidade econômica, precariedade na infraestrutura e debilidade na assistência institucional comprometeram a permanência das famílias nos lotes. A exploração madeireira já estabelecida na região consolidou-se como principal opção para aqueles que permaneceram no local, o que evitou a derrubada maciça da floresta no assentamento. Embora variando dentre os lotes em função de sua proximidade à rodovia que corta o assentamento, a cobertura florestal média em seu limite é de 80%. As taxas de desmatamento relativas ao longo desse período oscilaram tanto em função de forças locais favorecendo a conversão florestal como de causas subjacentes ocorrendo em contextos regionais, nacionais ou globais. A exploração dos recursos florestais no assentamento reduziu a densidade (476.7 indivíduos ha -1 , p < 0.001), área basal (23.3 m 2 ha -1 , p < 0.001) e biomassa seca acima do solo (295.7 Mg ha -1 , p = 0.008) de árvores na área de estudo. Foi calculada uma redução na biomassa arbórea seca acima do solo na área de estudo de aproximadamente 12% em relação ao valor médio encontrado nas florestas não alteradas da região. Assentamentos humanos mal planejados e administrados em meio à floresta densa da região amazônica não só abrem a fronteira para a conversão da cobertura florestal como para a exploração de um vasto estoque de madeira, provocando desmatamento e degradação nesses ecossistemas. Compreender as entrelinhas permeando a relação entre homem e meio ambiente é fundamental para o desenvolvimento de alternativas mais interessantes e adequadas à realidade local e para a elaboração de propostas de novos modelos de ocupação e desenvolvimento para a região

What’s governance got to do with it? Examining the relationship between governance and deforestation in the Brazilian Amazon

Deforestation continues at rapid rates despite global conservation efforts. Evidence suggests that governance may play a critical role in influencing deforestation, and while a number of studies have demonstrated a clear relationship between national-level governance and deforestation, much remains to be known about the relative importance of subnational governance to deforestation outcomes. With a focus on the Brazilian Amazon, this study aims to understand the relationship between governance and deforestation at the municipal level. Drawing on the World Bank Worldwide Governance Indicators (WGI) as a guiding conceptual framework, and incorporating the additional dimension of environmental governance, we identified a wide array of publicly available data sources related to governance indicators that we used to select relevant governance variables. We compiled a dataset of 22 municipal-level governance variables covering the 2005–2018 period for 457 municipalities in the Brazilian Amazon. Using an econometric approach, we tested the relationship between governance variables and deforestation rates in a fixed-effects panel regression analysis. We found that municipalities with increasing numbers of agricultural companies tended to have higher rates of deforestation, municipalities with an environmental fund tended to have lower rates of deforestation, and municipalities that had previously elected a female mayor tended to have lower rates of deforestation. These results add to the wider conversation on the role of local-level governance, revealing that certain governance variables may contribute to halting deforestation in the Brazilian Amazon.Fil: Benzeev, Rayna. State University of Colorado at Boulder; Estados UnidosFil: Wilson, Bradley. No especifíca;Fil: Butler, Megan. No especifíca;Fil: Massoca, Paulo. Indiana University; Estados UnidosFil: Paudel, Karuna. University of Georgia; Estados UnidosFil: Redmore, Lauren. Texas A&M University; Estados UnidosFil: Zarbá, Lucía. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentin

Environmental gradients and the evolution of successional habitat specialization: A test case with 14 Neotropical forest sites

https://www.scopus.com/inward/record.url?eid=2-s2.0-84939570316&partnerID=40&md5=fcadae8e6c274e8b7efca96099304a7cSuccessional gradients are ubiquitous in nature, yet few studies have systematically examined the evolutionary origins of taxa that specialize at different successional stages. Here we quantify successional habitat specialization in Neotropical forest trees and evaluate its evolutionary lability along a precipitation gradient. Theoretically, successional habitat specialization should be more evolutionarily conserved in wet forests than in dry forests due to more extreme microenvironmental differentiation between early and late-successional stages in wet forest. We applied a robust multinomial classification model to samples of primary and secondary forest trees from 14 Neotropical lowland forest sites spanning a precipitation gradient from 788 to 4000 mm annual rainfall, identifying species that are old-growth specialists and secondary forest specialists in each site. We constructed phylogenies for the classified taxa at each site and for the entire set of classified taxa and tested whether successional habitat specialization is phylogenetically conserved. We further investigated differences in the functional traits of species specializing in secondary vs. old-growth forest along the precipitation gradient, expecting different trait associations with secondary forest specialists in wet vs. dry forests since water availability is more limiting in dry forests and light availability more limiting in wet forests. Successional habitat specialization is non-randomly distributed in the angiosperm phylogeny, with a tendency towards phylogenetic conservatism overall and a trend towards stronger conservatism in wet forests than in dry forests. However, the specialists come from all the major branches of the angiosperm phylogeny, and very few functional traits showed any consistent relationships with successional habitat specialization in either wet or dry forests. Synthesis. The niche conservatism evident in the habitat specialization of Neotropical trees suggests a role for radiation into different successional habitats in the evolution of species-rich genera, though the diversity of functional traits that lead to success in different successional habitats complicates analyses at the community scale. Examining the distribution of particular lineages with respect to successional gradients may provide more insight into the role of successional habitat specialization in the evolution of species-rich taxa

Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1%of the total study area).Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forestmanagement, natural regeneration of second-growth forests provides a low-costmechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. © 2016 The Authors

Biodiversity recovery of Neotropical secondary forests

Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. Copyright © 2019 The Authors, some rights reserved

Tackling Deforestation at Subnational Scales in the Brazilian Amazon: Diverse Municipalities, Agents, and the Struggle for Collective Action in a Moving Frontier

Thesis (Ph.D.) - Indiana University, School of Public and Environmental Affairs, 2020The Brazilian Amazon is a mosaic of social-cultural and environmental realities, urban and rural. Home to 28 million people living across hundreds of municipalities, the region has been the stage for conflicting narratives and demands over conservation and development. How do agents across diverse municipalities respond to national anti-deforestation policies in the Amazon? This dissertation examined the development of the Brazilian forest legislation, the trajectory of colonization, territorial occupation, and development of Amazonian municipalities, and the implications of one emblematic national antideforestation policy targeting municipalities along the region’s expanding frontier: the List of Priority Municipalities (LPM). The LPM policy has imposed tough sanctions on municipalities considered hotspots of deforestation, being considered innovative for requiring both individual and collective actions to curtail deforestation. This research adopted a social-ecological systems’ perspective, drawing upon the Institutional Analysis and Development framework to guide systematic data collection, integration, and analysis. Mixed methods were combined to analyze archival documents, geospatial and official secondary datasets compiled for 530 municipalities in the Amazon biome, and in-depth case studies and interviews with diverse stakeholders. That provided complementary evidence to the multi-spatial and temporal analysis of three questions. First, the dissertation drew upon archival research and past forest regulations to ask how narratives and values about forests have evolved. Second, it compiled official secondary data at the municipal level and used logistic regression models to inquiry about the factors and local attributes affecting compliance with the LPM policy. Third, the research combined multivariate analysis and indepth case studies to examine interactions both between the geographical context of listed municipalities and within the region’s moving frontier, as well as to analyze factors underlying collaboration among local agents. Findings show that forest legislation and narratives about the value of forests have expanded in scope, resulting in more stringent and comprehensive regulations. However, interest groups have recurrently contested the societal value of forests, undermining forest regulations that threaten sectoral activities. Further, results revealed that historical-geographical factors defined municipal attributes and conditions across the moving frontier that have either facilitated or hindered local responses to LPM sanctions. The location of municipalities in areas undergoing different phases of occupation and transformation significantly affected the ability of local agents and municipal governments to comply with policy criteria applied similarly across the region. The analysis highlights the importance of strengthening law enforcement and municipal environmental governance, and the relevance of inter-institutional cooperation among governments, markets, and civil organizations. The study shows both challenges and opportunities for balancing regional development and forest conservation through collaboration among diverse groups of agents and levels of governance

We protect when we value: History of Brazilian forestry legislation

We examine various narratives of the values of trees and forests encapsulated in Brazilian legislation since the 16th century. The analysis reveals the evolution of a progressively more encompassing set of values associated with trees and forests, which gradually informed more stringent and comprehensive regulations. Besides protecting trees and forests for their timber and non-timber resources (material contributions), the legislation has adopted stricter definitions and rules recognizing both their regulating (soil conservation, water regime regulation, climate change mitigation) and non-material contributions (spiritual, cultural, and symbolic meanings) for society. Such advances have co-evolved with opposing land tenure interests and narratives regarding indigenous and traditional peoples. Interest groups continually revive outdated narratives portraying forests as unproductive lands that obstruct sectoral activities related to agriculture, mining, and infrastructure, resulting in the erosion of environmental governance and in socio-environmental conflicts. Our historical analysis reveals that past counter-reactions to forest degradation resulted in advances and innovative possibilities for socio-environmental development upon which the future of the Brazilian Amazon depends.&nbsp;Examinamos narrativas sobre os valores de árvores e florestas nas leis brasileiras desde o século XVI. Progressivamente, um conjunto mais abrangente de valores associados a florestas vem sendo traduzido em regulamentações mais rigorosas e inclusivas. Além de proteger árvores e florestas por seus recursos madeireiros e não madeireiros (contribuições materiais), instrumentos legais adotaram definições e regras mais rígidas reconhecendo suas contribuições reguladoras (conservação dos solos, regulação dos regimes hídricos e mitigação das mudanças climáticas) e não materiais (significados espiritual, cultural e simbólico) para a sociedade. Tais avanços coevoluíram com interesses fundiários e narrativas opostas às florestas e aos povos indígenas e tradicionais. Continuamente, grupos de interesse resgatam narrativas ultrapassadas para retratar florestas como terras improdutivas que obstruem atividades setoriais relacionadas à agricultura, mineração e infraestrutura, gerando conflitos socioambientais e a erosão da governança ambiental. A história revela um passado de contrarreações à degradação florestal resultando em avanços e novas possibilidades de desenvolvimento socioambiental das quais o futuro da Amazônia brasileira depende.&nbsp

Dinâmica espaço-temporal da vegetação secundária no município de Apuí (AM)

Secondary forests accounted for over one-third (266.000 km2) of the total deforested area in the Legal Amazon by 2008. This study analyzed the spatial and temporal dynamics of secondary forests in Apuí (AM), Brazil, municipality in which the expansion of cattle ranching has caused substantial increases in deforestation. A multi temporal series of 10 Landsat TM 5 satellite was classified by the maximum likelihood method in Envi 4.7 software. Mappings were analyzed by logical expressions using Dinamica EGO software, which allowed the extraction of information related to the land cover dynamics in the landscape. It also allowed the evaluation of the methodology employed in the images classification. The results pointed to the intensive land use system established in the region, where deforestation rates were above the average found in the whole Amazon in the last decade. The dynamics of secondary forest was associated temporally to the date of images acquisition and spatially to the local dynamics of pastures expansion and maintenance. The high land use dynamics in the region resulted in a high decrease of secondary forests; on average, only 10% of the secondary forests mapped in a year remain in the landscape after six years. The methodology employed in our study was useful for mapping land cover. The use of tools that allowed the overlay of classified images and the extraction of their quantitative information were essential to the refinement and analysis of data, minimizing errors associated with the process of classifying satellite imagery.Pages: 7639-764

Amazon Rain Forest Succession: Stochasticity or Land-Use Legacy?

Land-use practices can dramatically shift the trajectories of rain forest recovery. In a 25-year study, Amazon rain forest regenerated following deforestation as long as seed availability and seedling recruitment were not interrupted. In contrast, rain forest converted to cattle pastures via cutting and burning prior to abandonment diverted succession, leading to highly simplified stands dominated by a single genus. Annual fires eliminated seedlings, saplings, coppice, and seeds in the soil, except for several Vismia species. Once established, Vismia regenerated by continual resprouting and resisted the establishment of other rain forest species, especially the normal suite of pioneers. Through time, succession both in abandoned clearcuts and pastures increased in stem density and biomass; however, species accumulation and ecosystem services were limited in pastures when compared with those in abandoned clearcuts. Therefore, prescribed burning to maintain pastureland leaves a legacy that is not readily extinguished, whereas abandoning clearcuts engenders an accelerated rain forest regeneration.</p