Multitemporal monitoring of paramos as critical water sources in Central Colombia.

Paramos, unique and biodiverse ecosystems found solely in the high mountain regions of the tropics, are under threat. Despite their crucial role as primary water sources and significant carbon repositories in Colombia, they are deteriorating rapidly and garner less attention than other vulnerable ecosystems like the Amazon rainforest. Their fertile soil and unique climate make them prime locations for agriculture and cattle grazing, often coinciding with economically critical deposits such as coal which has led to a steady decline in paramo area. Anthropic impact was evaluated using multispectral images from Landsat and Sentinel over 37 years, on the Guerrero and Rabanal paramos in central Colombia which have experienced rapid expansion of mining and agriculture. Our analysis revealed that since 1984, the Rabanal and Guerrero paramos have lost 47.96% and 59.96% of their native vegetation respectively, replaced primarily by crops, pastures, and planted forests. We detected alterations in the spectral signatures of native vegetation near coal coking ovens, indicating a deterioration of paramo health and potential impact on ecosystem services. Consequently, human activity is reducing the extent of paramos and their efficiency as water sources and carbon sinks, potentially leading to severe regional and even global consequences.

Assessing the impact of three biosphere reserves on the conservation of coastal ecosystems.

Biosphere Reserves (BR) manage large territories with diverse natural covers and land uses to preserve biodiversity, promote local development and preserve ecosystems. This study evaluated how their zoning (buffer and core) and policy timeframes (decree period, management plan period, and land planning period) influence four landscape management outcomes: deforestation, natural cover recovery, and anthropic and natural permanence. For three Mexican BR case studies, land use and cover transitions were calculated and compared to contrafactual sites. Observed rates of land cover change were marginal within all three BR zoning and across their policy timeframe (<0.02 % change rate), suggesting that BR effectively promote the permanence of both natural and anthropic covers. Nevertheless, the predicted probability of uncommon deforestation and recovery outcomes at local levels showed that the effect of a BR over its regulated landscape is not spatiotemporally static, contrasting the effect of individual allocation vs a group or network. Poverty, land tenure, agriculture aptitude and distance to markets adds to this dynamic and is modelled and discussed. This study shows that BR zoning schemes and its regulatory sequence influence the rates of land cover change and the predicted probability of landscape management outcomes across space and time.

Transformation of Brazil's biomes: The dynamics and fate of agriculture and pasture expansion into native vegetation.

Land use and cover change (LUCC) in Brazil encompass a complex interplay of diverse factors across different biomes. Understanding these dynamics is crucial for informed decision-making and sustainable land management. In this study, we comprehensively analyzed LUCC patterns and drivers using 30 m resolution MapBiomas Collection 6.0 data (1985-2020). By mapping deforestation of primary and secondary natural vegetation, natural vegetation regeneration, and transitions between pasture, soybean, agriculture, and irrigation, we shed light on the intricate nature of LUCC in Brazil. Our findings highlight significant and increasing trends of deforestation in primary vegetation in the country. Simultaneously, the Atlantic Forest, Caatinga, Pampa, and other regions of the Cerrado have experienced intensification processes. Notably, the pasture area in Brazil reached its peak in 2006 and has since witnessed a gradual replacement by soybean and other crops. While pasture-driven deforestation persists in most biomes, the net pasture area has only increased in the Amazon and Pantanal, decreasing in other biomes due to the conversion of pasturelands to intensive cropping in other regions. Our analysis further reveals that primary and secondary vegetation deforestation accounts for a substantial portion of overall forest loss, with 72 % and 17 %, respectively. Of the cleared areas, 48 % were in pasture, 9 % in soybean cultivation, and 16 % in other agricultural uses in 2020. Additionally, we observed a lower rate of deforestation in the Atlantic Forest, a biome that has been significantly influenced by anthropogenic activities since 1986. This holistic quantification of LUCC dynamics provides a solid foundation for understanding the impacts of these changes on local to continental-scale land-atmosphere interactions. By unraveling the complex nature of LUCC in Brazil, this study aims to contribute to the development of effective strategies for sustainable land management and decision-making processes.

South American Dry Chaco rangelands: Positive effects of cattle trampling and transit on ecohydrological functioning.

Livestock production in drylands requires consideration of the ecological applications of ecohydrological redistribution of water. Intensive cattle trampling and the associated increase of surface runoff are common concerns for rangeland productivity and sustainability. Here, we highlight a regional livestock production system in which cattle trails and trampling surrounding an artificial impoundment are purposely managed to enhance redistribution and availability of water for cattle drinking. Based on literature synthesis and field measurements, we first describe cattle production systems and surface water redistribution in the Dry Chaco rangelands of South America, and then develop a conceptual framework to synthesize the ecohydrological impacts of livestock production on these ecosystems. Critical to this framework is the pioshere-a degraded overgrazed and overtrampled area where vegetation has difficulties growing, usually close to the water points. The Dry Chaco rangelands have three key distinctive characteristics associated with the flat sedimentary environment lacking fresh groundwater and the very extensive ranching conditions: (1) cattle drinking water is provided by artificial impoundments filled by runoff, (2) heavy trampling around the impoundment and its adjacent areas generates a piosphere that favors runoff toward the impoundment, and (3) the impoundment, piosphere, and extensive forage areas are hydrologically connected with a network of cattle trails. We propose an ecohydrological framework where cattle transit and trampling alter the natural water circulation of these ecosystems, affecting small fractions of the landscape through increased runoff (compaction in piosphere and trails), surface connectivity (convergence of trails to piosphere to impoundment), and ponding (compaction of the impoundment floor) that operate together making water harvesting and storage possible. These effects have likely generated a positive water feedback on the expansion of livestock in the region with a relatively low impact on forage production. We highlight the role of livestock transit as a geomorphological agent capable of reshaping the hydrology of flat sedimentary rangelands in ways that can be managed positively for sustainable ranching systems. We suggest that the Dry Chaco offers an alternative paradigm for rangelands in which cattle trampling may contribute to sustainable seminatural production systems with implications for other dry and flat rangelands of the world.

Disentangling the landscape during armed conflicts and postpeace agreements: Clues from Colombia's Andes-Amazon region.

The link between remote sensing and armed conflict processes has been evaluated through discrete landscape representations, deforestation, and static land cover maps. Yet, the landscape is dynamic-not discrete, and recognizing its evolution through armed conflict processes provides better-informed management and a more profound understanding of landscape dynamics. We must create continuous variables that provide compelling landscape representations that account for armed conflict processes as a driver of land cover and land-use change. Here, we present the advancements in monitoring landscape changes in Colombia from subannual forest change and annual land cover maps to elucidate illicit land use and habitat connectivity status. This evolution delivers critical elements to understanding the consequences of armed conflict processes on the environment. Integr Environ Assess Manag 2023;19:355-359. © 2022 SETAC.

Application of remote sensing to analyze the loss of natural vegetation in the Jalapão Mosaic (Brazil) before and after the creation of protected area (1970-2018).

This study aims to map the changes in land use and land cover between 1970 and 2018, analyzing the influence of the protected area s (PAs) in the Cerrado biome, specifically in the area of the Jalapão Mosaic. Images from the Landsat 1-MSS, 5-TM, and 8-OLI satellites were used and processed in SPRING and ArcGIS software. The analyses were based on three approaches: (1) the boundary of the Jalapão Mosaic, (2) the PAs, and (3) a comparison between the PAs and their surroundings. The Jalapão Mosaic results demonstrated that 26% (≅ 8410 km2) of the area was burned, and 15.5% (4971 km2) was anthropized in at least one of the analyzed periods. Among the PAs, the Serra Geral do Tocantins Ecological Station (Integral Protection) presented the largest burned area (43.7% ≅ 3095 km2); however, there was no significant increase in the anthropized areas due to fire. Meanwhile, the anthropized areas in the Rio Preto and Serra da Tabatinga Environmental Protection Areas (Sustainable Use) increased by 27.5% and by 75%, respectively, due to agricultural expansion. By analyzing the two groups of PAs and their surroundings, it was observed that the loss of natural vegetation was restrained and fires were less intense in the Integral Protection Units; in the Sustainable Use Units, there was a significant increase in the anthropized areas. Furthermore, over 70% of the anthropized areas occurred in the surrounding areas, thus showing the importance of creating PAs.

Ephemeral forest regeneration limits carbon sequestration potential in the Brazilian Atlantic Forest.

Although deforestation remains widespread in the tropics, many places are now experiencing significant forest recovery (i.e., forest transition), offering an optimistic outlook for natural ecosystem recovery and carbon sequestration. Naturally regenerated forests, however, may not persist, so a more nuanced understanding of the drivers of forest change in the tropics is critical to ensure the success of reforestation efforts and carbon sequestration targets. Here we use 35 years of detailed land cover data to investigate forest trajectories in 3014 municipalities in the Brazilian Atlantic Forest (AF), a biodiversity and conservation hotspot. Although deforestation was evident in some regions, deforestation reversals, the typical forest transition trajectory, were the prevalent trend in the AF, accounting for 38% of municipalities. However, simultaneous reforestation reversals in the region (13% of municipalities) suggest that these short-term increases in native forest cover do not necessarily translate into persistent trends. In the absence of reversals in reforestation, forests in the region could have sequestered 1.75 Pg C, over three times the actual estimated carbon sequestration (0.52 Pg C). We also showed that failure to distinguish native and planted forests would have masked native forest cover loss in the region and overestimated reforestation by 3.2 Mha and carbon sequestration from natural forest regeneration by 0.37 Pg C. Deforestation reversals were prevalent in urbanized municipalities with limited forest cover and high agricultural productivity, highlighting the importance of favorable socioeconomic conditions in promoting reforestation. Successful forest restoration efforts will require development and enforcement of environmental policies that promote forest regeneration and ensure the permanence of regrowing forests. This is crucial not only for the fate and conservation of the AF, but also for other tropical nations to achieve their restoration and carbon sequestration commitments.

Impacts of land cover change on the plant resources of an endangered pollinator.

One of the key drivers of pollinator declines is land cover change. We documented for the first time the impacts of over three decades of land cover change in Mexico on the plant resources of an endangered migratory pollinator, the Mexican long-nosed bat, Leptonycteris nivalis. This species is considered endangered under national and international criteria due to population declines over 50% in the past 10 years. Pregnant females of this bat species migrate every year following the blooms of Agave spp. from central Mexico to the southern United States; moving pollen over its 1,200 km long migratory corridor and pollinating distant populations of Agave spp. Increases in human populations density and agricultural expansion may be reducing agave habitat over time. The objective of our study is to understand the land cover change trends in the northern range of the bat and identify potential fragmentation patterns in the region. We analyzed changes that occurred in three vegetation types where agaves are found in five time periods 1985, 1993, 2002, 2007 and 2011. The area of the three vegetation types selected was reduced by using only the overlap with potential agave habitat created with ecological niche modeling algorithms to obtain the available agave habitat. We then calculated fragmentation metrics for each period. We found a significant portion of habitat lost mainly due to expansion in agriculture. The total number of patches increased after 1985. Only 9% of the available agave habitat in 2011 is inside the limits of protected areas. We recommend restoring agave populations in depleted areas to help prevent soil erosion and provide multiple socio-economic benefits for the region in the short term, and, in the long-term maintaining foraging resources for nectar-feeding bats.

Spatio-temporal analysis of the hydrological response to land cover changes in the sub-basin of the Chicú river, Colombia.

During the last years, in the sub-basin of the Chicú river, the agricultural and cattle exploitation has intensified and has depleted the water resources, thereby causing a deficit that has limited the continuity of such agricultural activity. Therefore, it is necessary to quantify land use and land cover changes contribute to the hydrological response to achieve sustainable management of the water resources in the sub-basin. In this sense, an integrated approach was used, which includes the SWAT (Soil and Water Assessment Tool) hydrological model and the different LUCC (Land use and cover change) maps obtained through tele-detection by using Landsat images to decide the hydrological response in the basin with the changes in land cover and uses in 1997, 2001, 2006, 2011, and 2016. As a result of the SWAT modeling, it can be noticed that the surface run-off varies according to the type of cover and extension, increasing or decreasing the water flow according to the characteristics of each cover, as in the case of bare lands (AGRL). While in 2006 it represented an area of 7.32% with a run-off of 39.25 mm, in 2001 its area decreased to 5.66% with a run-off of 44.9 mm. Moreover, in 1997 a flow of 4.45 m 3 / s can be observed, whereas in 2001 it decreases by 15% in the main current, which can be justified by a decrease of 8.8% in dense (FRSD) and fragmented (FRDT) forests. For 2006 and 2011 scenarios, the flow increases 13% and 50%, respectively, which corresponds to an increase of 36% and 48% concerning 2001 in clean grasses (PAST); despite the increase in clean grasses (PAST), the surface run-off was maintained almost constant above 9 mm, and it is thus considered a more stable vegetation cover.

Crossing a critical threshold: Accelerated and widespread land use changes drive recent carbon and nitrogen dynamics in Vichuquén Lake (35°S) in central Chile.

Global afforestation/deforestation processes (e.g., Amazon deforestation and Europe afforestation) create new anthropogenic controls on carbon cycling and nutrient supply that have not been fully assessed. Here, we use a watershed-lake dynamics approach to investigate how human-induced land cover changes have altered nutrient transference during the last 700 years in a mediterranean coastal area (Vichuquén Lake). We compare our multiproxy reconstruction with historical documentation and use satellite images to reconstruct land use/cover changes for the last 45 years. Historical landscape changes, including those during the indigenous settlements, Spanish conquest, and the Chilean Republic up to mid-20th century did not significantly alter sediment and nutrient fluxes to the lake. In contrast, the largest changes in the lake-watershed system occurred in the mid-20th century and particularly after the 1980s-90s and were characterized by a large increase in total nitrogen and organic carbon fluxes as well as negative shifts in sediment δ15N and δ13C values. This shift was coeval with the largest land cover transformation in the Vichuquén watershed, as native forests nearly disappeared while anthropogenic tree plantations expanded up to 60% of the surface area.

Forest fires and deforestation in the central Amazon: Effects of landscape and climate on spatial and temporal dynamics.

Forest fires and deforestation are the main threats to the Amazon forest. Extreme drought events exacerbate the impact of forest fire in the Amazon, and these drought events are predicted to become more frequent due to climate change. Fire escapes into the forest from agriculture and pasture areas. We assessed the potential drivers of deforestation and forest fires in the central Brazilian Amazon and show that over a period of 31 years (1985-2015) forest fires occurred only in years of extreme drought induced by El Niño (1997, 2009 and 2015). The association of forest fires with strong El Niños shows the vulnerability of forest to climate change. The areas deforested were closely associated with navigable rivers: 62% of the total deforestation from 2000 to 2018 was located within the 2 km of rivers. There was a notable increase in deforestation and forest fire during the 2015 El Niño in comparison to previous years. Only a small part of the forest that burned was deforested in the years following the wildfires: 7% (1997), 3% (2009) and 1.5% (2015). Forest close to roads, rivers and established deforestation is susceptible to deforestation and fire since these areas are attractive for agriculture and pasture. Indigenous land was shown to be important in protecting the forest, while rural settlement projects attracted both forest fire and deforestation. Of the total area in settlement projects, 40% was affected by forest fires and 17% was deforested. Rivers are particularly important for deforestation in this part of Amazonia, and efforts to protect forest along the rivers are therefore necessary. The ability to predict where deforestation and fires are most likely to occur is important for designing policies for preventative actions.

Assessment of above-ground biomass and carbon loss from a tropical dry forest in Mexico.

Primary forests in seasonally dry tropical regions have undergone intense land-use/cover change, ranging from widespread shifting agriculture to land clearing for livestock production systems, and selective logging. Despite the importance of tropical dry forests (TDF), little is known about the implications of carbon (C) emissions from deforestation in local, national, and global scales. Therefore, the main objective of this study is to quantify and understand the processes that drive major C losses of this ecosystem in Mexico. Also, we evaluated the applicability of the already published above ground biomass (AGB) maps to quantify and allocate changes in C stocks. The results suggest that biomass maps can be used to capture the patterns of AGB distribution and to identify the driving forces of C emissions. The C losses are more related to socioeconomic drivers than biophysical characteristics like topography and climate. Besides, this study shows that published current AGB maps may be used for landscape management, including conservation and restoration areas.

Mapping LULC types in the Cerrado-Atlantic Forest ecotone region using a Landsat time series and object-based image approach: A case study of the Prata River Basin, Mato Grosso do Sul, Brazil.

In the last 30 years, the growth of the agriculture and livestock industries in the Cerrado biome has caused severe changes in land use and land cover (LULC), and areas previously occupied by native vegetation are changing to agricultural monocultures (e.g., soybean or corn) and/or pastures. Thus, the objective of this study was to analyze the LULC changes for the years 1986, 1999, 2007, and 2016 based on Landsat time series and object-based image analysis (OBIA) for the Prata River Basin. Twelve LULC classes were mapped: riparian forest, cerrado, swampy grasslands, wetlands, semideciduous forest, pasture, agriculture, fallow agricultural land, barren land, eucalyptus, water bodies, and burnt area. The classifications presented results with an overall accuracy of more than 93% and a kappa coefficient of 0.92. In 2007, the pasture class had the highest increase in area (48.5%), with a total area of 118.32 km2 of Cerrado biome vegetation converted to pasture, and the classes banhado, riparian forest, swampy grasslands, and cerrado had the greatest reductions in area (41.58%, 29.67%, 25.44%, and 21.63%, respectively). More precisely, the wetlands class underwent the greatest decrease under the advancement of pasture in the studied period (- 36.2%). These changes are due to factors favorable to agropastoral practices, such as a flat relief and soil with good agricultural suitability. Graphical abstract.

Trends in fragmentation and connectivity of Paspalum quadrifarium grasslands in the Buenos Aires province, Argentina.

BACKGROUND: Despite its wide distribution worldwide, only 4.6% of temperate grasslands are included within systems of protected areas. In Argentina, this situation is even more alarming: only 1.05% is protected. The study area (central area of the southern Salado River basin) has a large extent of grasslands of Paspalum quadrifarium (Pq) which has been target since the middle of the last century of a variety of agricultural management practices including fire burning for cattle grazing. METHODS: Five binary images of presence-absence data of Pq from a 42-year range (1974-2016) derived from a land cover change study were used as base data. Morphological Spatial Pattern Analysis (MSPA), Morphological Change Detection (MCD) and Network Connectivity Analysis (NCA) were performed to the data using Guidos Toolbox (GTB) for the estimation of habitat and connectivity dynamics of the Pq patches (fragments). RESULTS: A loss of the coverage area and habitat nuclei of this grassland was observed during the study period, with some temporal oscillation but no recovery to initial states. Additional drastic reduction in connectivity was also evident in resulting maps. The number of large Pq grassland fragments (>50 ha) decreased at beginning of the study period. Also, fragmentation measured as number of components (patches) was higher at the end of the study period. The Pq pajonal nuclei had their minimum representativeness in 2000, and recovered slightly in area in 2011, but with a significant percentage increase of smaller patches (=islets) and linear elements as bridges and branches. Large corridors (mainly edge of roads) could be observed at the end of the study period, while the total connectivity of the landscape pattern drops continuously. Statistics of links shows mean values decreasing from 1974 to 2016. On the other hand, maximum values of links decreased up to 19% in 2011, and recovered to a 54% of their original value in 2016. DISCUSSION: Pq fragmentation and habitat reduction could have an impact on the ecosystem functioning and the mobility of some species of native fauna. The connecting elements of the landscape were maintained and/or recovered in percentage in 2011 and 2016. This fact, although favoring the dispersion of the present diversity in the habitat nuclei could cause degradation by an edge effect. Part of the area has the potential to be taken as an area of research and as an example of livestock management, since it is the one that would most preserve the biodiversity of the Pq environment. On the methodological side, the use of a proved tool as GTB is useful for monitoring dynamics of a grassland-habitat fragmentation.

Spatial near future modeling of land use and land cover changes in the temperate forests of Mexico.

The loss of temperate forests of Mexico has continued in recent decades despite wide recognition of their importance to maintaining biodiversity. This study analyzes land use/land cover change scenarios, using satellite images from the Landsat sensor. Images corresponded to the years 1990, 2005 and 2017. The scenarios were applied for the temperate forests with the aim of getting a better understanding of the patterns in land use/land cover changes. The Support Vector Machine (SVM) multispectral classification technique served to determine the land use/land cover types, which were validated through the Kappa Index. For the simulation of land use/land cover dynamics, a model developed in Dinamica-EGO was used, which uses stochastic models of Markov Chains, Cellular Automata and Weight of Evidences. For the study, a stationary, an optimistic and a pessimistic scenario were proposed. The projections based on the three scenarios were simulated for the year 2050. Five types of land use/land cover were identified and evaluated. They were primary forest, secondary forest, human settlements, areas without vegetation and water bodies. Results from the land use/land cover change analysis show a substantial gain for the secondary forest. The surface area of the primary forest was reduced from 55.8% in 1990 to 37.7% in 2017. Moreover, the three projected scenarios estimate further losses of the surface are for the primary forest, especially under the stationary and pessimistic scenarios. This highlights the importance and probably urgent implementation of conservation and protection measures to preserve these ecosystems and their services. Based on the accuracy obtained and on the models generated, results from these methodologies can serve as a decision tool to contribute to the sustainable management of the natural resources of a region.

Human-environmental drivers and impacts of the globally extreme 2017 Chilean fires.

In January 2017, hundreds of fires in Mediterranean Chile burnt more than 5000 km2, an area nearly 14 times the 40-year mean. We contextualize these fires in terms of estimates of global fire intensity using MODIS satellite record, and provide an overview of the climatic factors and recent changes in land use that led to the active fire season and estimate the impact of fire emissions to human health. The primary fire activity in late January coincided with extreme fire weather conditions including all-time (1979-2017) daily records for the Fire Weather Index (FWI) and maximum temperature, producing some of the most energetically intense fire events on Earth in the last 15-years. Fire activity was further enabled by a warm moist growing season in 2016 that interrupted an intense drought that started in 2010. The land cover in this region had been extensively modified, with less than 20% of the original native vegetation remaining, and extensive plantations of highly flammable exotic Pinus and Eucalyptus species established since the 1970s. These plantations were disproportionally burnt (44% of the burned area) in 2017, and associated with the highest fire severities, as part of an increasing trend of fire extent in plantations over the past three decades. Smoke from the fires exposed over 9.5 million people to increased concentrations of particulate air pollution, causing an estimated 76 premature deaths and 209 additional admissions to hospital for respiratory and cardiovascular conditions. This study highlights that Mediterranean biogeographic regions with expansive Pinus and Eucalyptus plantations and associated rural depopulation are vulnerable to intense wildfires with wide ranging social, economic, and environmental impacts, which are likely to become more frequent due to longer and more extreme wildfire seasons.

Near doubling of Brazil's intensive row crop area since 2000.

Brazil has become a global leader in the production of commodity row crops such as soybean, sugarcane, cotton, and corn. Here, we report an increase in Brazilian cropland extent from 26.0 Mha in 2000 to 46.1 Mha in 2014. The states of Maranhão, Tocantins, Piauí, Bahia (collectively MATOPIBA), Mato Grosso, Mato Grosso do Sul, and Pará all more than doubled in cropland extent. The states of Goiás, Minas Gerais, and São Paulo each experienced >50% increases. The vast majority of expansion, 79%, occurred on repurposed pasture lands, and 20% was from the conversion of natural vegetation. Area of converted Cerrado savannas was nearly 2.5 times that of Amazon forests, and accounted for more than half of new cropland in MATOPIBA. Spatiotemporal dynamics of cropland expansion reflect market conditions, land use policies, and other factors. Continued extensification of cropland across Brazil is possible and may be likely under current conditions, with attendant benefits for and challenges to development.

Impactos por cambio de uso de suelo en las áreas naturales protegidas de la región central de la Sierra Madre Oriental, México / Impact of land use cover change on protected natural areas in central region of Sierra Madre Oriental, Mexico

Resumen Los cambios en el uso de suelo y la cubierta vegetal, derivados de la expansión y extensión de асtividades antrópicas, generan impactos negativos en la biodiversidad y la provisión de servicios ecosistémicos, y contribuyen significativamente en los procesos de cambio climatico a nivel regional. Las Áreas Naturales Protegidas (ANP) representan un instrumento de política pública para hacer frente a las tendencias de cambio y transformación de los ecosistemas, además de permitir la conservación de los recursos. El objetivo de este estudio fue determinar el impacto potencial del cambio en el uso de suelo y la cobertura vegetal de las ANP de la región сеntral de la Sierra Madre Orientai (SMO), en México, a través del análisis espacial y la simulación de escenarios de cambio potencial. Se usaron imágenes satelitales para elaborar mapas de cambio en coberturas vegetales, entre los años 1989, 2000 y 2005, y con base en un conjunto de variables biofísicas y socioeconómicas, se simuló un escenario de cambio al 2025. Se determinó que la tasa de cambio de las cubiertas vegetales de la SMO en el periodo estudiado fue de 0.54 % en selvas, 0.22 % en bosques y 0.23 % en matorrales; y en las ANP fue de 0.34 % y 0.60 % para selvas y bosques, respectivamente. En este lapso se perdieron 1 578.26 ha de selvas, bosques y matorrales, al interior de las ANP. De mantenerse las tendencias actuales de cambio en el uso de la tierra, otras 4 542.17 ha estarán en riesgo de perderse en un futuro cercano. Los resultados indican que las ANP estudiadas están sometidas a presiones de cambio en el uso de la tierra, que amenazan la conservación del patrimonio natural que resguardan, por 10 que deberían rediseñarse las estrategias de manejo y monito reo a corto y mediano plazo.

Abstract Land use cover change, resulting from the expansion and extension of human activities, generates negative impact on biodiversity and the provision of ecosystem services, as well as contributing significantly to climate change processes at a regional level. Natural Protected Areas (NPA) represent a public policy instrument to address the trends of change and ecosystem transformation, while allowing the conservation of resources. The objective of this study was to determine the potential impact of the processes involved in land use cover change on the NPA as part of the central region at the Sierra Madre Oriental (SMO) in Mexico by using the special analysis and the scenery simulation of potential change. Satellite imagery was used to determine the changes in natural vegetation cover between 1989, 2000 and 2005 and, using a set of biophysical and socioeconomic variables, a change scenario was simulated for 2025. This study found that the rate of change of vegetation cover at the SMO over the research period was 0.54 % in tropical forests, 0.22 % in forests and 0.23 % in scrublands, while those in NPA were 0.34 % and 0.60 % in tropical forests and forests respectively; 1 578.26 ha of tropical semi-deciduous temperate forest and scrublands were lost from the NPA. If the current land use trends change continues, another 4 542.17 ha are likely to be modified in the future. These results indicate that NPA under study are subject to the pressures of land use change that threaten the natural heritage under protection and that, therefore, management strategies and monitoring need to be redesigned in the short and medium term.

Spatiotemporal mapping of soybean plantations in Rondônia, Western Brazilian Amazon / Mapeamento espaço-temporal de plantios de soja no estado de Rondônia, Amazônia ocidental brasileira

Although soybean production has been increasing in the state of Rondônia in the last decade, soybean planted area has been estimated indirectly using secondary datasets, which has limited understanding of its spatiotemporal distribution patterns. This study aimed to map and analyze spatial patterns of soybean expansion in Rondônia. We developed a classification technique based on Spectral Mixture Analysis (SMA) derived from Landsat imagery and Decision Tree Classification to detect and map soybean plantations in 2000, 2005, 2010, and 2014. The soybean classification map showed 93% global accuracy, 23% omission and 0% of commission errors for soybean crop fields. The greatest increases of soybean cropped area in the state of Rondônia were observed between 2000-2005 and 2005-2010 time-periods (33,239 ha and 59,628 ha, respectively), mostly located in Southern Rondônia. The expansion of soybean areas to Northern Rondônia (25,627 ha) has mostly occurred in the 2010-2014 time period. We estimate that 95.4% of all newly created soybean plantations, detected by 2014, were established on lands deforested nine or more years earlier. We concluded that the incursion of soybean plantations on lands deforested for other land uses (e.g. ranching) is contributing to their displacement (pastures) from older colonization zones toward more remote frontier areas of the Amazon, exacerbating new deforestation there.(AU)

Os plantios de soja têm aumentado ao Norte e Sul dos municípios de Rondônia na última década, entretanto a área plantada de soja tem sido estimada utilizando dados secundários, o que limita o entendimento da distribuição espaço temporal da soja. Este estudo buscou analisar e mapear os padrões espaciais de expansão da soja em Rondônia. O mapeamento de plantios de soja nos anos 2000, 2005, 2010 e 2014 foi feito a partir de uma técnica de classificação baseada na análise de mistura espectral de imagens Landsat e em uma árvore de decisão. A acurácia global, erros de omissão e comissão para o mapeamento da soja foram 93%, 23% e 0%, respectivamente. Os resultados mostraram que os maiores incrementos da área de soja ocorreram no estado de Rondônia entre os períodos de 2000-2005 e 2005-2010 (33,239 ha e 59,628 ha, respectivamente). A expansão das áreas de soja para o norte de Rondônia (25,627 ha) ocorreu em sua maioria no período de 2010 a 2014. Observou-se que 95,4% de todos os plantios de soja detectados em 2014 ocorreram em áreas com pelo menos nove anos de desmatamento. Além disso, encontramos evidências de que os plantios de soja estão contribuindo para o deslocamento de usos da terra prévios de antigas zonas de colonização, predominantemente pastos que foram empurrados para outras áreas de fronteiras da Amazônia, e lá exacerbando novos desmatamentos.(AU)

Cambios en la cobertura de manglares en Bahía Culebra, Pacífico Norte de Costa Rica (1945-2010) / Changes in mangrove coverage in Culebra Bay, North Pacific of Costa Rica (1945-2010)

ResumenLos manglares tienen gran importancia ecológica, económica, riqueza natural y prestan servicios ambientales. No obstante, son amenazados por la sobreexplotación, la contaminación y el cambio de uso de suelo. Costa Rica tiene manglares en las costas pacífica y caribeña. Según algunos estudios, la cobertura de manglar ha ido disminuyendo desde la década de 1980. Debido a que estos datos no son actualizados y se basan en estimaciones poco precisas, es necesario hacer una valoración de la extensión actual y la variación de la cobertura en los últimos años, que permita determinar cambios. En esta investigación se estudió la cobertura de dos manglares ubicados en Bahía Culebra, Pacífico Norte: Iguanita y Playa Panamá. Se usaron fotografías e imágenes de satélite para un período de 65 años (1945-2010). Se encontraron cambios espaciotemporales en la cobertura de manglar, bosques adyacentes y áreas sin vegetación. Las menores coberturas de manglar se registraron en la década de 1970, pero aumentaron en años posteriores. Los cambios en la cobertura de bosque alrededor de los manglares de Iguanita y Playa Panamá concuerdan con otros análisis históricos sobre el uso del suelo alrededor de Bahía Culebra. Antes de 1980 se dio un aumento de las prácticas de ganadería extensiva e intensiva, lo que aumentó la tasa de deforestación. Después de 1980 se abandonaron estas prácticas y la cobertura de bosque secundario aumentó hasta el año 2000. Para asegurar una adecuada protección de los manglares, es necesario evaluar también las áreas aledañas y establecer zonas de amortiguamiento alrededor, para reducir los impactos futuros.

Abstract:Despite the economic and environmental services that mangroves provide, they continue to be threatened by overexploitation, pollution, and land use change. Costa Rica has mangrove areas on the Pacific and Caribbean coasts, and cover has been declining since the 1980s. However, data on mangrove coverage are not continually updated and are often based on inaccurate estimates. It is therefore necessary to assess the current extension and variation of the mangrove cover in recent years, to determine changes. The mangrove cover was analyzed in two mangrove forests located in Bahía Culebra, North Pacific: Iguanita and Playa Panamá. For this, aerial photographs and satellite imagery were used to study changes for a 65 year period (1945-2010). Spatio-temporal changes were found in mangrove coverage, adjacent forests and areas without vegetation. Lower mangrove cover occurred during the 1970s (28.4 ha in Iguanita and 4.8 ha in Playa Panamá); but increased in recent years (38.9 ha in Iguanita and 12.0 ha in Panamá). Changes in forest cover by the Iguanita and Playa Panama mangroves were related to the history of land use around Bahía Culebra. Before 1980, there was extensive and intensive cattle ranching, increasing the deforestation rate; after that year, these practices were abandoned and secondary forest coverage increased until 2000. To ensure the adequate protection of mangroves, it is not only important to protect mangrove forests, but it is also necessary to establish buffer zones on their surroundings, to mitigate and/or reduce possible impacts. Rev. Biol. Trop. 64 (3): 955-964. Epub 2016 September 01.