Land cover-land use (LCLU) classification tasks can take advantage of the fusion of radar and optical remote sensing data, leading generally to increase mapping accuracy. Here we propose a ...methodological approach to fuse information from the new European Space Agency Sentinel-1 and Sentinel-2 imagery for accurate land cover mapping of a portion of the Lower Magdalena region, Colombia. Data pre-processing was carried out using the European Space Agency's Sentinel Application Platform and the SEN2COR toolboxes. LCLU classification was performed following an object-based and spectral classification approach, exploiting also vegetation indices. A comparison of classification performance using three commonly used classification algorithms was performed. The radar and visible-near infrared integrated dataset classified with a Support Vector Machine algorithm produce the most accurate LCLU map, showing an overall classification accuracy of 88.75%, and a Kappa coefficient of 0.86. The proposed mapping approach has the main advantages of combining the all-weather capability of the radar sensor, spectrally rich information in the visible-near infrared spectrum, with the short revisit period of both satellites. The mapping results represent an important step toward future tasks of aboveground biomass and carbon estimation in the region.
Abstract
Tropical deforestation is mainly driven by agricultural expansion, land grabbing, illegal logging, urbanization, cattle ranching as well as mining. However, extraction of minerals and its ...impacts in high biodiversity regions are still poorly known, particularly in Colombia, a tropical megadiverse hotspot. Here, using high-resolution datasets of forest cover changes and detailed geospatial mining data for Colombia, we show a growing contribution of legal mining to national deforestation: 3.4% over the 2001–2018 period, with a peak at 5.6% in 2017. During this period, around 121 819 ha have been deforested inside legal mining concessions, and an estimation of over 400 000 ha deforested by both legal and illegal. Gold and coal are the most important legally-mined materials in Colombia associated to deforestation, particularly in the recent years with 511% and 257% tree cover loss increases respectively (average over 2016–2018 compared to 2001–2015 average of mined material deforestation average). Three Colombian departments summed out ∼70% of the national deforestation occurring in legal concessions: in 2018, up to 23% of deforestation in Antioquia was taking place in legal mines (gold producer). Finally, we found that only 1% (respectively, 3%) of the concessions contribute to 60% (>90%) of the legal mining-related deforestation, mainly driven by large clearings to agriculture. Environmental law enforcement, monitoring activities and engaging the mining industry in effective forest conservation and landscape restoration strategies are urgently needed in Colombia for preserving biodiversity and ecosystem services.
•Colombia critically needs high-resolution information on land-use land-cover.•We present new LULC products for the Colombian Amazon and Andes at 30 m resolution.•The products show high overall ...accuracy and improve current coarser LULC datasets.•Classification and validation procedures are based on the Earth Engine platform.•All procedures used are open access and distributable to the scientific community.
Land use-land cover (LULC) data are critical inputs for policy and scientific research in hydrology, climatology, territory planning and conservation. Colombia, a megadiverse country and deforestation hotspot on Earth, critically needs recent and high-resolution information on land use and land cover. Using Landsat OLI 8 data, we here present a new LULC product for the Colombian Amazon and Andes at 30 m × 30 m resolution for year 2018, using classification and validation procedures based on the Google Earth Engine cloud-based platform. The novel products show high overall accuracy (>90%), are achieved with high automatization and improve current coarser LULC datasets for Colombia. All the processing procedures used are open access and distributable to the scientific community.
Deforestation and natural resource extraction are well-known threats to biodiversity conservation, environmental justice, livelihoods, ecosystem services and can even result in crimes to, and ...harassment of, environmental defenders. Such punitive actions against environmental defenders can influence both economic development and forest conservation efforts. Yet, little is known about this nexus and the complex relationships between environmental impacts, such as deforestation, and environmental crimes across space and time in many regions such as Latin America. We explored these complex relationships using a database of environmental crimes, threats, and harassment (ECTH) affecting environmental defenders, as well as forest loss data, and municipal-level socioeconomic indicators for nine Latin American countries over a period of eleven years. We found that as deforestation increased, there was a large increase in ECTH episodes related to agricultural activity, while in highly populated municipalities there were more ECTH episodes related to energy production, transportation, and urbanization activities. Overall, the percentage of annual deforestation had a strong influence, which varied according to municipal wealth, population density (PD), and geographical context. Statistically significant increases in violent crimes were found with increasing deforestation, but only in Honduras, Guatemala, and Mexico, and in municipalities with lower population densities. Conversely, higher income, more populated municipalities were characterized by judicial harassment, as opposed to violent crimes, indicating a type of Environmental Crime Kuznets Curve relationship. A structural equation model where deforestation was driven by the number of ECTHs, as well as percent forest area, PD, latitude, and country showed that the number of ECTH events and country were significant drivers of deforestation. Understanding these complex social-ecological dynamics shows the profound effects that deforestation and unsustainable, and unjust, environmental impacts and conflicts can have across forests and ecosystems of the Global South in terms of social justice and conservation, and thus merits increased protection of environmental defenders in Latin America.
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•Socio-ecological settings modulate spatio-temporal change of tropical forest loss.•We use a spatially explicit model to quantify the influence of deforestation drivers.•The ...long-lasting internal conflict showed contrasting effects on historical deforestation.•The effect of deforestation drivers largely varies among regions.•Results highlight the need of locally-adapted governance to control deforestation.
Characterizing and managing deforestation are some of the most urgent environmental challenges in the tropics. Forest loss depends on multiple drivers that relate to ecological and socio-economic conditions, and varies significantly in time and space. Understanding the causes and potential consequences of forest loss in a region, requires detailed knowledge of the spatial and temporal behavior of deforestation drivers. This is especially important in Colombia, a country with an immense geographical, ecological and cultural diversity. In this work we use a spatially-explicit modeling platform to identify the influence of multiple deforestation drivers in different biogeographical and planning regions of Colombia. Models were used to produce different deforestation scenarios, resulting in contrasting trends. Results suggest that agricultural activities have a significant role in deforestation in Colombia, although its influence largely varies among regions. Notably, the long-lasting internal conflict in the country, indicated here by a proxy variable, produced contrasting effects on historical deforestation, such that in some areas it acted as an attractor and in some others as a deterrent of deforestation. Our scenarios for the mid-21st century indicate that current trends in deforestation and its drivers (except the internal conflict due to a recent peace agreement) can potentially lead to major ecological impacts, such as fragmentation and loss of connectivity among ecosystems. In the Governance scenario, however, enforcement of conservation in protected areas ensures partial forest conservation, highlighting the key relevance of these areas for biodiversity conservation in the country and for controlling the expansion of deforestation. Given the high spatial and temporal variability of deforestation, and that the same drivers can lead to different responses in different geographic areas, decision-making needs a more efficient approach for designing locally-adapted measurements to face current challenges of conservation and management of forests and their services.
There is a complex interplay of criminal groups’ control over land, illicit activities, and forest cover change in the Colombian Andes-Amazon region. This area is dealing with diverse forms of ...conflict and peace, directly impacting landscape connectivity. While many studies have documented rapid deforestation after the peace agreement in 2016, we know little about the effect of these socio-political changes on the state of landscape connectivity. We disentangle habitat from connected habitat in forest ecosystems using the Landsat archive and landscape connectivity indices. We find that in the Andes-Amazon region during 2000–2020, connected habitat loss reached 18%, while habitat loss was 13%. This result is worrisome because it indicates that well-connected patches are more fragmented and isolated, affecting the natural connections between the Andes and Amazon biogeographical regions and the movement ability of species. The Colombian government should conduct a strategic peacebuilding process incorporating structural changes that prevent the increase of large-scale extractive activities that are often illegal in the region. While finding a balance between extractive activities and conservation remains a big challenge, legal land tenure, census/taxation, and specific agreements with local actors can initially prevent deforestation. We discourage localized military actions and the return of aerial fumigation of coca fields, which rather than stop deforestation might exacerbate land cover change deeper into pristine forests.
•De-escalation of conflict coincides with intra-annual deforestation dynamics in Colombia.•Connected habitat loss (18%) is higher than habitat available (13%) during 2000–2020.•Rapid fragmentation of well-connected forest patches can affect the biological connection between the Andes-Amazon biomes.•Reachable habitat for species is now less than the habitat available.•Conservation strategies should focus on developing agreements with local communities.
High Andean forests are biodiversity hotspots that also play key roles in the provisioning of vital ecosystem services for neighboring cities. In past centuries, the hinterland of Andean fast-growing ...cities often experienced a dramatic decline in forested areas, but there are reports that forest cover has been recovering recently. We analyzed aerial imagery spanning the years 1940 to 2007 from nine administrative localities in the Eastern Andean Cordillera of Colombia in order to elucidate precise patterns of forest vegetation change. To this aim, we performed image object-based classification by means of texture analysis and image segmentation. We then derived connectivity metrics to investigate whether forest cover trajectories showed an increase or decrease in fragmentation and landscape degradation. We observed a forest cover recovery in all the examined localities, except one. In general, forest recovery was accompanied by an increase in core habitat areas. The time scale of the positive trends identified partially coincides with the creation of protected areas in the region, which very likely furthered the recovery of forest patches. This study unveils the long-term dynamics of peri-urban high Andean forest cover, providing valuable information on historical vegetation changes in a highly dynamic landscape.
Rapid deforestation has been well-documented in Colombia after the 2016 peace agreement with FARC. While many analysis using remote sensing identify land cover change, structural connectivity ...variables are less studied for understanding landscape transformation. In this work, we used data from the Landsat archive from 2011 to 2021, the Continuous Change Detection and Classification algorithm (CCDC), and Morphological Spatial Pattern Analysis (MSPA) to analyze deforestation, land cover change, and landscape connectivity in northwestern Colombia’s Amazon. We examined the spatial patterns in three specific subsets in the Colombian arc of deforestation, with a special focus on the surroundings of the National Natural Park Serranía de Chiribiquete. Our results confirm changes in structural connectivity linked to pasture expansion from the conversion forest to pasture during the analyzed period showing changes in the borders of Serranía de Chiribiquete National Park along rivers and roads, where cattle is transported. Before 2016, the average annual deforested area in the three study areas was 27.93 km²; after 2016, this number increased to 73.36 km². The outcomes of our study contribute to an improved understanding of pasture dynamics. They can aid decision-making in areas that play a key role in ecological networks necessary for long-term conservation efforts. Our quantitative assessments have revealed a temporal shrinking of the core area, indicative of a decline in forest cover. Concurrently, we observed an expansion of the edge and background areas, which is consistent with the proliferation of pastures. This study presents methodology and data in support of policy-making for sustainable land use and ecological connectivity to mitigate further environmental degradation in the area.
The cost effective monitoring of habitats and their biodiversity remains a challenge to date. Earth Observation (EO) has a key role to play in mapping habitat and biodiversity in general, providing ...tools for the systematic collection of environmental data. The recent GEO-BON European Biodiversity Observation Network project (EBONE) established a framework for an integrated biodiversity monitoring system. Underlying this framework is the idea of integrating in situ with EO and a habitat classification scheme based on General Habitat Categories (GHC), designed with an Earth Observation-perspective. Here we report on EBONE work that explored the use of NDVI-derived phenology metrics for the identification and mapping of Forest GHCs. Thirty-one phenology metrics were extracted from MODIS NDVI time series for Europe. Classifications to discriminate forest types were performed based on a Random Forests™ classifier in selected regions. Results indicate that date phenology metrics are generally more significant for forest type discrimination. The achieved class accuracies are generally not satisfactory, except for coniferous forests in homogeneous stands (77–82%). The main causes of low classification accuracies were identified as (i) the spatial resolution of the imagery (250 m) which led to mixed phenology signals; (ii) the GHC scheme classification design, which allows for parcels of heterogeneous covers, and (iii) the low number of the training samples available from field surveys. A mapping strategy integrating EO-based phenology with vegetation height information is expected to be more effective than a purely phenology-based approach.
Few studies analyze people’s preferences for ecosystem services (ES), disservices (ED) and drivers of change in less populated, tropical municipalities. Understanding such preferences and needs by ...the community and stakeholder groups before actually assessing, modelling, and measuring the supply of ES is key for decision-making and planning in municipalities, as well as for the conservation of nearby neotropical dry forests. We studied these dynamics in a small rural municipality in Colombia with limited data availability using semi-structured interviews and surveys, as well as ES-proxies and geospatial analyses. We then analyzed the supply and importance of two community identified ES and one ED from adjacent neotropical dry forests during 2005–2017. We found that respondents recognized air purification and food production as the most important ES. Increased temperatures and fires were the most important ED, while fires were also identified as an important driver of change. Air purification, via pollutant deposition to forest cover, remained approximately constant (116 ton/year), while food production (49 ton/ha) and fire occurrence, an ED, increased. Findings show how transdisciplinary research and participatory knowledge co-production among local communities, researchers and land management institutions can improve governance, decision making, policy uptake and planning efforts.
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