Terrestrial mammal responses to habitat structure and quality of remnant riparian forests in an Amazonian cattle-ranching landscape

Extensive 1970–2010 deforestation in the Brazilian Amazon has generated a ~ 1.5 Mha fragmented region known as the ‘arc of deforestation’. Farmers and cattle ranchers throughout Brazil are legally required to set-aside riparian forest strips within their landholdings, but recent legislative changes have relaxed the minimum mandatory conditions of these riparian forests. In this context, we assessed the functional role of riparian forest remnants as landscape connectors for medium to large-bodied terrestrial mammals in a vast fragmented landscape of southern Amazonia. We selected 38 riparian forest strips and five riparian sites within continuous forest, installed four to five camera-traps along each riparian zone (199 camera-trap stations), and sampled the terrestrial mammal assemblage for 60 days per station during the dry seasons of 2013 and 2014. We compared mammal use of riparian forests within both continuous and highly fragmented forests, and examined the effects of corridor width, corridor habitat structure, and landscape context on mammal species richness, composition, and functional diversity, all of which were higher in continuous forests than in riparian remnants. Functional diversity differences between corridor type was trait-independent and mediated by differences in species richness. Forest habitat degradation was associated with overall lower species richness, whereas forest specialists were more species-rich in increasingly wider corridors. Compositional shifts indicate that deforestation and forest degradation favours matrix-tolerant species with lower levels of forest habitat specificity. We show the potential landscape connectivity role for forest mammals of riparian corridors, whose width and forest degradation status are key predictors of community-wide responses. We provide evidence on the importance of these relict riparian strips to forest vertebrates, strengthening the scientific arguments that help justify the recently embattled legal requirements to maintain effective riparian corridors in Brazil

Áreas de preservação permanente como corredores ecológicos para a fauna de mamíferos de médio e grande porte no sul da Amazônia

Tese (doutorado) — Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Zoologia, 2016.A conectividade de uma paisagem é um dos fatores determinantes da viabilidade de populações animais, frente aos efeitos da perda e fragmentação do hábitat. Os corredores ecológicos são uma das estratégias defendidas para se manter a conectividade de uma paisagem fragmentada. No Brasil, a manutenção de áreas de preservação permanente (APP) ao longo de cursos d‘água, é prevista com o objetivo primário de preservar os recursos hídricos, mas as mesmas apresentam o potencial de funcionar como um elemento de conexão ubíquo em toda a paisagem. Nesta visão, elas funcionariam como corredores ecológicos. No entanto, é necessário compreender quais fatores estão envolvidos na utilização efetiva desses conectores pela fauna, incluindo aspectos como a largura, qualidade, configuração na paisagem, entre outros. Essas discussões são cruciais no momento em que temos que lidar com os possíveis efeitos negativos causados pelas alterações do Código Florestal Brasileiro, que afetam a necessidade de recomposição de um enorme passivo ambiental em APPs no país. Nesse contexto, a presente tese avaliou o papel das APPs como componentes espaciais que promovem a conectividade de paisagens fragmentadas do ponto de vista da fauna, especificamente de mamíferos terrestres de médio e grande porte. A tese está dividida em quatro capítulos, sendo o primeiro referente a uma revisão que introduz os conceitos e objetivos da manutenção de corredores ecológicos, tanto de acordo com a literatura ecológica quanto com a legislação brasileira. Os três capítulos seguintes fazem parte do trabalho empírico realizado em uma paisagem fragmentada no sul da Amazônia, e estão apresentados no formato de manuscritos científicos, em inglês. O primeiro capítulo revisa os conceitos sobre corredores ecológicos encontrados na teoria e aplicados na prática no Brasil, tanto em escalas locais quanto regionais. Também discute as vantagens e desvantagens de se investir em corredores como estratégia de manejo, de acordo com o que defensores e críticos apresentam na literatura. Finalmente, é discutido o potencial das APPs como elementos conectores em paisagens fragmentadas no Brasil e como as mudanças recentes (2012) no Código Florestal Brasileiro podem afetar esses elementos. O segundo capítulo apresenta um estudo empírico, em que se avaliou o uso dos corredores ecológicos em uma paisagem fragmentada no sul da Amazônia pela comunidade de mamíferos. Nesse sentido, foi avaliado como varia a riqueza, a composição e a diversidade funcional da comunidade nos fragmentos lineares nas APPs. Foram selecionadas 43 áreas riparias para o estudo, sendo 38 corredores ripários em APPs e cinco áreas pseudo-controles, em áreas de floresta contínua, em uma paisagem que compreendia três municípios no norte do estado do Mato Grosso (Alta Floresta, Carlinda e Paranaíta). Foram instaladas entre quatro e cinco armadilhas fotográficas em cada área selecionada para amostrar a fauna de mamíferos durante as estações secas de 2013 e 2014. A riqueza, composição e diversidade funcional foram comparadas entre as APPs e as áreas ripárias contínuas. Os resultados indicam que todas essas medidas foram maiores nas áreas controle do que em áreas ripárias desmatadas. Os padrões da comunidade nos corredores ripários de acordo com a largura, a qualidade estrutural, a configuração da paisagem também foram avaliados. A degradação da qualidade das florestas esteve associada a uma menor riqueza geral, enquanto a riqueza e diversidade funcional de espécies estritamente florestais foram maiores em corredores mais largos. A composição da comunidade indicou que a perda e degradação dos corredores ripários favorecem espécies tolerantes à matriz antrópica, composta basicamente por pastagens. A conclusão do estudo é que as APPs ripárias têm o potencial de funcionar como conectores na paisagem, mas que largura e degradação florestal são fatores chave na determinação do sucesso desses conectores. O terceiro capítulo consiste também na avaliação do papel das APPs como corredores ecológicos, mas com enfoque nos padrões de ocupação de cada espécie de mamífero. Com os mesmos dados obtidos com a amostragem apresentada no capítulo 2, modelos de ocupação que levam em consideração diferenças na detectabilidade foram feitos para 10 espécies: a capivara (Hydrochaeris hydrochoerus), a paca (Cuniculus paca), a cotia (Dasyprocta leporina), o saruê (Didelphis marsupialis), o tatu-galinha (Dasypus novemcinctus), a anta (Tapirus terrestris), o queixada (Tayassu pecari), o cateto (Pecari tajacu), o quati (Nasua nasua) e a irara (Eira barbara). Esses modelos também foram utilizados para testar o efeito da largura, da qualidade e do contexto dos corredores ripários avaliados como fatores explanatórios das variações 55 encontradas. Finalmente, os padrões obtidos foram extrapolados para as 1.915 demais matas ripárias identificadas nos três municípios e, desta forma, foi possível identificar as APPs com maior e menor potencial de manter as diferentes espécies na região. A ocupação de oito espécies respondeu aos fatores testados, e a degradação florestal foi novamente uma das variáveis mais importantes para explicar a probabilidade de ocupação de seis espécies. Na paisagem como um 60 todo, as matas ripárias que apresentaram um menor potencial de manter as espécies foram aquelas com baixa com qualidade florestal e este aspecto foi mais importante do que a estrutura de paisagem. Tais áreas, ou seja, APPs mais degradadas e com menor potencial de promover conectividade, estão localizadas no norte do município de Alta Floresta e em Carlinda, regiões com ocupação mais antiga. O quarto capítulo apresenta uma avaliação dos determinantes de perda e degradação de APPs ripárias, tanto ao longo de cursos d´água quanto de nascentes. Essa análise foi realizada somente no município de Alta Floresta, para onde havia um mapa disponível da rede hidrográfica completa (rios e nascentes) e de mais de 3.000 propriedades privadas delimitadas. Foi examinado como determinantes espaciais (distância da cidade, distância de estradas e o tamanho da propriedade) influenciam a área mantida e a qualidade da floresta nessas APPs. Ademais, os padrões observados foram relacionados à obediência à legislação, de acordo com o antigo (Lei 4771/65) e o novo Código Florestal (Lei 12.651/12). Os padrões de alteração que ocorrem no interior das matas ripárias em resposta à degradação florestal também foram descritos e explorados em uma escala mais local, com os dados empíricos coletados durante o 75 estudo descrito nos capítulos 2 e 3. A perda de habitat e a degradação florestal estão comumente associadas, mas ambos os aspectos podem responder de modo independente aos mesmos determinantes. Florestas ao redor de nascentes estavam em pior estado do que florestas ao longo de cursos d‘água, e ambos pequenos e grandes proprietários tenderam a remover áreas de nascente mais do que o permitido legalmente. A proximidade de estradas também influenciou negativamente a qualidade e quantidade de floresta remanescente nos dois casos, e a distância de cidades afetou todas as variáveis testadas exceto qualidade de mata de nascente. A degradação foi maior em florestas ripárias mais estreitas, e as mudanças estruturais detectadas no interior das matas inclui a intrusão de gado, que afeta a densidade de sub-bosque, e a diminuição da altura e homogeneidade do perfil da floresta.Landscape connectivity is one of the determinants of animal population viability in the face of habitat loss and fragmentation, and ecological corridors are one of the strategies used to safeguard the connectivity of a fragmented landscape. In Brazil, the maintenance of riparian forest buffers (Permanent Protection Areas, APP) along streams and rivers is prescribed by the environmental legislation with the primary goal of preserving the health of the hydrological systems, but they also have the potential of serving as a landscape connector, functioning as ecological corridors. It is however necessary to understand which factors influence the effective use of these connectors by the local fauna, such as corridor width, quality, configuration of the surrounding landscape, among others. This discussion is far from trivial, since we currently have to deal with the possible deleterious effects of the newly approved changes in the Brazilian Forest Code, which affect the restoration requirements in APPs across the country. In this context, the current work aimed at assessing the role of these APPs in promoting landscape connectivity for the native fauna, specifically the medium- and large-bodied terrestrial mammals. The thesis is divided into four chapters. The first is a review of the theme, which introduces the concepts and general goals of ecological corridors, both according to the scientific literature as well as to the Brazilian legislation. The following three chapters comprise the empirical work conducted in a highly fragmented landscape in the southern Amazon, and are presented in the form of scientific manuscripts, in English. The first chapter revises the concepts of ecological corridors found in the literature and applied in practice in Brazil, both at local and regional scales. It also presents the arguments pro and against corridors as a management strategy, according to proposers and critics of ecological corridors. Finally, we discuss the potential of APPs to act as landscape connectors in Brazil, and how the recent changes (2012) in the Brazilian Forest Code may affect this potential. The second chapter presents an empirical study, in which we assessed the use of ecological corridors by the community of terrestrial mammals in a fragmented landscape in southern Amazonia. We tested how community richness, composition, and functional diversity vary within linear riparian APP patches. We selected 43 riparian areas for the study, 38 of which were riparian remnants, and 5 were pseudo-control riparian areas embedded in continuous forest. The study landscape spanned three municipalities in the North of the state of Mato Grosso (Alta Floresta, Carlinda, and Paranaíta). From four to five camera traps were installed within each area selected to sample the mammal community during the dry seasons of 2013 and 2014. Community richness, composition, and functional diversity were compared between APPs and continuous riparian areas. Results indicated that all these response variables were higher in control areas. Community patterns within riparian remnants were also assessed according to corridor width, structural quality, and landscape configuration. Forest quality erosion was associated to a general lower richness, while the richness and functional diversity of forest specialist species were higher in larger corridors. Community composition shifts indicated that loss and degradation of riparian corridors favour matrix-tolerant species. This study concludes that riparian APPs have the potential of acting as landscape connectors, but that corridor width and degradation are key factors in determining the success of these elements as a management strategy. The third chapter also evaluates the role of the APPs as ecological corridors, but focuses on occupancy patterns of each analysed mammal species. With the same empirical data presented in Chapter 2, occupancy models, which take into consideration differences in detection probability, were built for ten species: the capybara (Hydrochaeris hydrochoerus), the lowland paca (Cuniculus paca), the red-rumped agouti (Dasyprocta leporina), the posssum (Didelphis marsupialis), the nine-banded armadillo (Dasypus novemcinctus), the tapir (Tapirus terrestris), the white-lipped peccary (Tayassu pecari), the collared peccary (Pecari tajacu), the coati (Nasua nasua) and the tayra (Eira barbara). These models were also used to test the effect of width, quality and landscape context of the sampled riparian remnants as explanatory variables. Finally, the observed patterns were extrapolated to 1915 remaining riparian forests, manually identified in the three municipal counties. We were therefore able to identify the APPs with the highest and lowest potential for maintaining the different species in the region. The occupancy probabilities of eight species responded to either one or more of the factors tested, and forest degradation was again the most important variable, explaining occupancy patterns of six species. In the landscape as a whole, the riparian patches that presented a lower potential for harbouring the species were those with low internal quality, and this factor was more important than landscape structure. These more highly degraded areas, with lower potential to promote landscape connectivity, were located in the North of the municipal county of Alta Floresta and in Carlinda, portions of the landscape with an earlier history of human occupation. The fourth and last chapter presents an evaluating of the driver of riparian APP loss and degradation, both along streams and around headwaters. This analysis was conducted for the Alta Floresta municipal county only, for which we had a map of the complete hydrological network and the headwaters sites, as well as a map of over 3000 private landholdings. We examined how spatial drivers (distance to town, distance to roads, and landholding size) affect the amount of forest set-asides and the quality of the forest in these APPs. Moreover, the observed patterns were associated to legislative compliance, according to both the previous (Bill 4771/65) and the new Forest Code (Bill 12.651/12). Environmental changes that occur within riparian forests associated to forest degradation were also explored at a more local scale, using the empirical data we obtained during the field study described in Chapters 2 and 3. Habitat loss and degradation are commonly associated, but they may also respond independently to the same drivers. Forest remnants around headwaters were generally worse off than remnants along streams, and both small and large landholders removed headwater forests more than legally permitted. Proximity to roads also negatively influenced the quality and amount of remnants forest in both cases, while distance to town affected all but one variable – headwater forest quality. Forest degradation was higher in narrower riparian forests, and structural changes detected within the remnants included: cattle intrusion, which affects understory density, and forest profile height and homogeneity

Anthropogenic drivers of headwater and riparian forest loss and degradation in a highly fragmented southern Amazonian landscape

Freshwater ecosystems across the Amazon are largely comprised of small streams and headwaters of riparian zones. These areas are legally protected within private landholdings in Brazil, but recent changes in the environmental legislation have slackened protection requirements, with unpredictable consequences to the integrity and functioning of these freshwater environments. Local drivers of riparian forest loss and degradation should be understood by considering context-dependent land management practices and pressures within a region. Here, we examine the spatial determinants of the total amount and spectral quality of both headwater and overall riparian forests within private landholdings within a highly fragmented region of southern Amazonia. We built generalized linear models to assess how the amount and spectral quality of headwater and riparian forests respond to landholding size and distance to roads and an urban center, and document landholder compliance rates according to both the current and previous Brazilian environmental legislation. Although forest loss and degradation are typically associated, forest degradation responded independently to the same drivers. Headwater forests were generally more degraded than riparian forests, and smallholders complied less often with legal requirements than largeholders. Proximity to roads and the nearest town had a detrimental effect on both headwater and riparian forest amount and quality, and distance to the nearest town affected all variables, except for headwater forest quality. Compliance with environmental legislation is the first step in protecting riparian and headwater forests, but alternative landscape management strategies must be explored, particularly focusing on smallholdings, which are most vulnerable to deforestation and forest degradation

Mind the gap: reconciling tropical forest carbon flux estimates from earth observation and national reporting requires transparency

Background: The application of different approaches calculating the anthropogenic carbon net flux from land, leads to estimates that vary considerably. One reason for these variations is the extent to which approaches consider forest land to be “managed” by humans, and thus contributing to the net anthropogenic flux. Global Earth Observation (EO) datasets characterising spatio-temporal changes in land cover and carbon stocks provide an independent and consistent approach to estimate forest carbon fluxes. These can be compared against results reported in National Greenhouse Gas Inventories (NGHGIs) to support accurate and timely measuring, reporting and verification (MRV). Using Brazil as a primary case study, with additional analysis in Indonesia and Malaysia, we compare a Global EO-based dataset of forest carbon fluxes to results reported in NGHGIs. Results: Between 2001 and 2020, the EO-derived estimates of all forest-related emissions and removals indicate that Brazil was a net sink of carbon (− 0.2 GtCO2yr−1), while Brazil’s NGHGI reported a net carbon source (+ 0.8 GtCO2yr−1). After adjusting the EO estimate to use the Brazilian NGHGI definition of managed forest and other assumptions used in the inventory’s methodology, the EO net flux became a source of + 0.6 GtCO2yr−1, comparable to the NGHGI. Remaining discrepancies are due largely to differing carbon removal factors and forest types applied in the two datasets. In Indonesia, the EO and NGHGI net flux estimates were similar (+ 0.6 GtCO2 yr−1), but in Malaysia, they differed in both magnitude and sign (NGHGI: -0.2 GtCO2 yr−1; Global EO: + 0.2 GtCO2 yr−1). Spatially explicit datasets on forest types were not publicly available for analysis from either NGHGI, limiting the possibility of detailed adjustments. Conclusions: By adjusting the EO dataset to improve comparability with carbon fluxes estimated for managed forests in the Brazilian NGHGI, initially diverging estimates were largely reconciled and remaining differences can be explained. Despite limited spatial data available for Indonesia and Malaysia, our comparison indicated specific aspects where differing approaches may explain divergence, including uncertainties and inaccuracies. Our study highlights the importance of enhanced transparency, as set out by the Paris Agreement, to enable alignment between different approaches for independent measuring and verification

Woody aboveground biomass mapping of the brazilian savanna with a multi-sensor and machine learning approach

The tropical savanna in Brazil known as the Cerrado covers circa 23% of the Brazilian territory, but only 3% of this area is protected. High rates of deforestation and degradation in the woodland and forest areas have made the Cerrado the second-largest source of carbon emissions in Brazil. However, data on these emissions are highly uncertain because of the spatial and temporal variability of the aboveground biomass (AGB) in this biome. Remote-sensing data combined with local vegetation inventories provide the means to quantify the AGB at large scales. Here, we quantify the spatial distribution of woody AGB in the Rio Vermelho watershed, located in the centre of the Cerrado, at a high spatial resolution of 30 metres, with a random forest (RF) machine-learning approach. We produced the first high-resolution map of the AGB for a region in the Brazilian Cerrado using a combination of vegetation inventory plots, airborne light detection and ranging (LiDAR) data, and multispectral and radar satellite images (Landsat 8 and ALOS-2/PALSAR-2). A combination of random forest (RF) models and jackknife analyses enabled us to select the best remote-sensing variables to quantify the AGB on a large scale. Overall, the relationship between the ground data from vegetation inventories and remote-sensing variables was strong (R2 = 0.89), with a root-mean-square error (RMSE) of 7.58 Mg ha−1 and a bias of 0.43 Mg ha−1

Thresholds of riparian forest use by terrestrial mammals in a fragmented Amazonian deforestation frontier

Species persistence in fragmented landscapes is intimately related to the quality, structure, and context of remaining habitat remnants. Riparian vegetation is legally protected within private landholdings in Brazil, so we quantitatively assessed occupancy patterns of terrestrial mammals in these remnants, examining under which circumstances different species effectively use them. We selected 38 riparian forest patches and five comparable riparian sites within continuous forest, at which we installed four to five camera-traps per site (199 camera-trap stations). Terrestrial mammal assemblages were sampled for 60 days per station during the dry seasons of 2013 and 2014. We modelled species occupancy and detection probabilities within riparian forest remnants, and examined the effects of patch size, habitat quality, and landscape structure on occupancy probabilities. We then scaled-up modelled occupancies to all 1915 riparian patches throughout the study region to identify which remnants retain the greatest potential to work as habitat for terrestrial vertebrates. Of the ten species for which occupancy was modelled, six responded to forest quality (remnant degradation, cattle intrusion, palm aggregations, and understorey density) or structure (remnant width, isolation, length, and area of the patch from which it originates). Patch suitability was lower considering habitat quality than landscape structure, and virtually all riparian remnants were unsuitable to maintain a high occupancy probability for all species that responded to forest patch quality or structure. Beyond safeguarding legal compliance concerning riparian remnant amount, ensuring terrestrial vertebrate persistence in fragmented landscapes will require curbing the drivers of forest degradation within private landholdings

Improving estimations of GHG emissions and removals from land use change and forests in Brazil

Brazil ranks fifth in greenhouse gas emissions globally due to land use change. As a signatory to the Paris Agreement, Brazil must periodically report its GHG emissions as well as present mitigation targets set in the Nationally Determined Contribution (NDC). The SEEG Brazil Initiative (Greenhouse Gas Emission and Removal Estimating System) generates independent estimates of GHG emissions and removals since 2013, and in 2020, the estimation method for the land use change sector has been improved. This study aimed to (1) present these methodological advancements, including the spatial allocation of annual emissions and removals due to land use change (LUC) in Brazil at a 30 m spatial scale, and (2) explore the emission and removal patterns observed in Brazil from 1990 to 2019. The method presented here is built upon—but improves—the approach used by Brazil’s official National Inventories to estimate GHG emissions and removals. The improvements presented here include exploring emissions to the municipality level and using an annual updated time series of land use and land cover maps. Estimated greenhouse gas emissions from the LUC sector ranged from 687 Mt of CO _2 e in 2011 to a peak of 2150 Mt of CO _2 e in 2003. In 2010, removals nearly offset gross emissions in the sector, with a net emission of 116 Mt of CO _2 e. The trend observed in recent years was an increase in emissions, decreasing Brazil’s likelihood of meeting its NDC targets. Emission profiles vary across the country, but in every biome, the conversion of primary native vegetation is the predominant transition type. If Brazil managed to curb deforestation, the total GHG emissions from the land use change sector would decrease by 96%, mitigating around 44% of total emissions

Dataset from paper: "Mind the Gap: Reconciling tropical forest carbon flux estimates from Earth Observation and National Reporting requires transparency"

This repository contains the processed data used in the publication of Heinrich et al., 2023 (Mind the Gap: Reconciling tropical forest carbon flux estimates from Earth Observation and National Reporting requires transparency). Carbon Balance and Management. When using this data, full reference to the raw data publications and the publication Heinrich et al., 2023 must be made. The raw datasets used in this study are all available from their original sources