Dolors Armenteras

Andean forest fragmentation and the representativeness of protected natural areas in the eastern Andes, Colombia

Biodiversity characterization at the landscape level based on remote sensing and geographic information systems data has become increasingly important for conservation planning. We present the results of a study of the fragmentation of Andean forests and other ecosystems and an assessment of the representativeness at the ecosystem level of protected natural areas in the eastern Andes of Colombia. We used satellite remote sensing data to characterize ecosystems and undertook ground truthing at six sites. The 11 identified ecosystem types were analyzed within existing protected areas to assess the representativeness of these sites within the region. Five ecosystems were well-represented and six of them had < 10% of their area protected. Highland ecosystems were the best represented in protected areas due to the preponderance of highland parks in the eastern Andes. However Andean and sub Andean forests have less than 4.5 and 6.4% of their original pre-Columbian extent currently protected. Fragmentation parameters such as patch size, patch shape, number of patches, mean nearest neighbor distance and landscape shape index were also analyzed. Andean, sub Andean and dry forests are highly fragmented ecosystems but there is a clear latitudinal gradient of fragmentation. Our findings suggested that conservation efforts should be directed first toward the conservation of dry and oak forests in the center of the eastern Andes, and then Andean and sub Andean montane forests toward the south near the border with Ecuador. # 2003 Elsevier Science Ltd. All rights reserved.

Landscape Dynamics in Northwestern Amazonia: An Assessment of Pastures, Fire and Illicit Crops as Drivers of Tropical Deforestation

Many studies have identified drivers of deforestation throughout the tropics and, in most cases, have recognised differences in the level of threat. However, only a few have also looked at the temporal and spatial dynamics by which those drivers act, which is critical for assessing the conservation of biodiversity as well as for landscape planning. In this study, we analyse land cover change between 2000 and 2009 in north-western Colombian Amazonia to identify the interactions between the use of fire, cultivation of illicit crops and establishment of pastures, and their impacts on the loss of forest in the region. Yearly analyses were undertaken at randomly selected sample areas to quantify the average areas of transition of land cover types under different landscape compositions: forest-dominated mosaics, pasture mosaics, fire mosaics, and illicit crop mosaics. Our results indicate that despite the fact that forest areas were well-preserved, deforestation occurred at a low annual rate (0.06%). Conversion to pasture was the main factor responsible for forest loss (the area of pastures tripled within forest mosaics over 8 years), and this process was independent of the landscape matrix in which the forests were located. In fire mosaics, burning is a common tool for forest clearing and conversion to pasture. Thus, forests in fire mosaics were highly disturbed and frequently transformed from primary to secondary forests. The use of fire for illicit cropping was not detected, partly due to the small size of common illicit crops. Forest regeneration from pastures and secondary vegetation was observed in areas with large amounts of natural forest. Overall, assuming the continuation of the observed pasture conversion trend and the use of forest fire, we suggest that our results should be incorporated into a spatially explicit and integrated decision support tool to target and focus land-planning activities and policies.

Dynamics, Patterns and Causes of Fires in Northwestern Amazonia

According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests.

Effectiveness of protected areas in the Colombian Andes: deforestation, fire and land-use changes

Protected areas (PAs) are one of the most common conservation strategies to halt biodiversity loss. However, little is known about their current effectiveness and how they could behave under projected scenarios of change, especially in the mountain ecosystems of the Andean region. In this study, we assess the role of protected areas against deforestation and fire incidence in the Colombian Andes and how variables associated with biophysical and context drivers such as the size, year of creation and geographic location of the PAs affect their effectiveness. For the long-term, we have addressed the question of how effective these areas will be under three different scenarios of change for the period between 2020 and 2050, including a reference scenario and two scenarios of increasing pastureland and croplands. The results obtained indicated that both deforestation and fire levels were significantly lower inside protected areas than outside their borders. Concerning variables affecting deforestation and fire, only the type of ecosystem affected these processes in this study. The magnitude of forest loss was different between the analysed scenarios and depended on the location of the PAs. The PAs located in the Western Mountain Range presented the largest values of deforestation but the lowest number of fire incidences. This finding could be related to the presence of processes other than fire, such as illegal logging or selective extraction. The largest losses are expected in the PAs associated with the Eastern and Central mountain ranges, whereas the Western Mountain range will have the lowest loss. We conclude that although the Andes Mountains are a highly transformed and dynamic region, the current PAs have been effective barriers for deforestation and fire. However, the creation of new areas and the maintenance of the current PAs should take into account the interaction with the surrounding population, especially in those areas that are more sensitive to change.

MODIS Reflectance and Active Fire Data for Burn Mapping in Colombia

Abstract Satellite-based strategies for burned area mapping may rely on two types of remotely sensed data: postfire reflectance images and active fire detection. This study uses both methods in a synergistic way. In particular, burned area mapping is carried out using MCD43B4 [Moderate Resolution Imaging Spectrometer (MODIS); Terra + Aqua nadir bidirectional reflectance distribution function (BRDF); adjusted reflectance 16-day L3 global 1-km sinusoidal grid V005 (SIN)] postfire datasets and MODIS active fire products. The developed methodology was tested in Colombia, an area not covered by any known MODIS ground antenna, using data from 2004. The resulting burned area map was validated using a high-spatial-resolution Landsat-7 Enhanced Thematic Mapper Plus (ETM+) image and compared to two global burned area products: L3JRC (terrestrial ecosystem monitoring global burnt area product) and MCD45A1 (MODIS Terra + Aqua burned area monthly global 500-m SIN grid V005). The results showed that this method would b...

Characteristics of natural salt licks located in the Colombian Amazon foothills

Salt licks are key places for the ecological dynamics of wildlife communities around the world and are locations where animals develop geophagical behaviours. Geophagy is a method for animals to supplement their diets or facilitate their digestive processes and is related to the health of individuals and populations. This study characterises a series of salt licks located in the Colombian Amazon foothills and describes their structural, mineralogical and physicochemical properties, as well as the fauna that visit these locations. The results are analysed in reference to the geological characteristics of the study area and in relation to the role of the salt lick in the nutritional ecology of the Amazonian fauna. Located in the study area are two types of salt licks that are significantly different in composition. These salt licks are located in an area where young geological materials have been exposed. The characteristics of the salt licks supports the hypothesis that they are used to solve nutritional problems that result from herbivorous diets. The clear importance of salt licks in the ecology of several Amazonian animal species emphasises the need to prioritise conservation areas by maximising the complementarities of salt lick sites.

Methodology for Evaluating the Quality of Ecosystem Maps: A Case Study in the Andes

Uncertainty in thematic maps has been tested mainly in maps with discrete or fuzzy classifications based on spectral data. However, many ecosystem maps in tropical countries consist of discrete polygons containing information on various ecosystem properties such as vegetation cover, soil, climate, geomorphology and biodiversity. The combination of these properties into one class leads to error. We propose a probability-based sampling design with two domains, multiple stages, and stratification with selection of primary sampling units (PSUs) proportional to the richness of strata present. Validation is undertaken through field visits and fine resolution remote sensing data. A pilot site in the center of the Colombian Andes was chosen to validate a government official ecosystem map. Twenty primary sampling units (PSUs) of 10 × 15 km were selected, and the final numbers of final sampling units (FSUs) were 76 for the terrestrial domain and 46 for the aquatic domain. Our results showed a confidence level of 95%, with the accuracy in the terrestrial domain varying between 51.8% and 64.3% and in the aquatic domain varying between 75% and 92%. Governments need to account for uncertainty since they rely on the quality of these maps to make decisions and guide policies.

Integrating remotely sensed fires for predicting deforestation for REDD

Fire is an important tool in tropical forest management, as it alters forest composition, structure, and the carbon budget. The United Nations program on Reducing Emissions from Deforestation and Forest Degradation (REDD+) aims to sustainably manage forests, as well as to conserve and enhance their carbon stocks. Despite the crucial role of fire management, decision-making on REDD+ interventions fails to systematically include fires. Here, we address this critical knowledge gap in two ways. First, we review REDD+ projects and programs to assess the inclusion of fires in monitoring, reporting, and verification (MRV) systems. Second, we model the relationship between fire and forest for a pilot site in Colombia using near-real-time (NRT) fire monitoring data derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). The literature review revealed fire remains to be incorporated as a key component of MRV systems. Spatially explicit modeling of land use change showed the probability of deforestation declined sharply with increasing distance to the nearest fire the preceding year (multi-year model area under the curve [AUC] 0.82). Deforestation predictions based on the model performed better than the official REDD early-warning system. The model AUC for 2013 and 2014 was 0.81, compared to 0.52 for the early-warning system in 2013 and 0.68 in 2014. This demonstrates NRT fire monitoring is a powerful tool to predict sites of forest deforestation. Applying new, publicly available, and open-access NRT fire data should be an essential element of early-warning systems to detect and prevent deforestation. Our results provide tools for improving both the current MRV systems, and the deforestation early-warning system in Colombia.

Identifying Municipal Risk Factors for Leftist Guerrilla Violence in Colombia

Abstract This study examines determinants of leftist violence at the municipal level in Colombia from 2000 through 2010. A multilevel GLMM model with a negative binomial distribution is used to take advantage of the information available at the municipal and department level. Surprisingly, inequality was not a significant covariate of violence, and agricultural GDP tended to reduce, instead of increase, guerrilla violence. The main risk factors identified include physical characteristics such as rugged topography and prior violence, but also factors that are candidates for policy action, such as unemployment, incorporation of the poor into public services, repression, and the energy and mining sector. These findings suggest interventions to decrease risks of guerrilla violence beyond merely strengthening the state. While repression tends to escalate violence, targeted policies to provide health benefits to those currently underserved, and securing mining and oil operations can effectively reduce the risk of violence.

Effects of seasonality and habitat on the browsing and frugivory preferences of Tapirus terrestris in north-western Amazonia

Herbivore foraging is influenced by spatial and seasonal changes in the production of leaves and fruits. To understand how herbivores respond to these changes, it is necessary to identify their habitat preferences and how they use the vegetation available. In the Neotropical region, one of the largest terrestrial herbivores is the lowland tapir ( Tapirus terrestris ), a species important for its dual role as browser and seed disperser. The objective of this study was to determine the species and plant components (leaves, fruits) utilized by T. terrestris in different time periods and habitats, in relation to changes in food availability in the north-western Amazon. Tapir diet was established through identification of browsing signs and faecal analysis, from data collected in the field during the months of March, April, August and September of 2015. Plant species availability for browsing was sampled in ten 2 × 50-m transects and fruit productivity was estimated in linear transects (~9 km). We found that T. terrestris mostly consumed vegetative parts, i.e. fibre (70–90%), and to a lesser extent fruits (10–30%). Food consumption was selective and concentrated in habitats with higher availability of preferred plants. When fruit intake increased, selectivity in browsing became more intense and limited to preferred species. This information, coupled with our findings about seasonal differences in browsing vs. frugivory patterns, provides valuable knowledge for understanding how environmental heterogeneity may influence the foraging ecology of the lowland tapir.