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We test for evidence of the Tropical Niche Conservatism or the Out of The Tropics hypotheses in structuring patterns of tree community composition along a 2000 + meter elevational gradient in the northern tropical Andes. By collecting and integrating data on the presence–absence of tree species within plots with phylogenetic information, we analyzed the following: (a) patterns of phylogenetic dispersion and species diversity along the elevational gradient based on indexes of net relatedness, nearest taxon relatedness, and species richness (α‐diversity); and (b) the replacement of lineages along the gradient using the PhyloSorensen metric (β‐diversity). More specifically, we established 20 0.25‐ha permanent tree inventory plots between 750 and 2,802 m asl where all individuals with diameter at breast height (DBH) ≥ 10 cm were measured and identified. We then used a series of linear models to test for changes in α and β diversity between plots in relation to elevation. Neither the net relatedness index nor the nearest taxon index showed a significant relationship with elevation. However, there was greater phylogenetic overdispersion at intermediate elevations; this likely reflects the mixing of species with contrasting origins from tropical and temperate lineages. β‐diversity between plots was negatively related to the corresponding difference in elevation, indicating that closely related lineages occupy similar ranges of elevation and temperature. We conclude that the immigration of lineages from extra‐tropical regions has significant effects in determining the phylogenetic structure of tree communities in tropical Andean forests. Abstract in Spanish is available with online material.

Los bosques tropicales almacenan grandes cantidades de carbono en su biomasa, y por ello juegan un papel determinante en el ciclo global de este elemento. Las variables biofísicas determinan la capacidad de almacenamiento de los bosques como reservorios de carbono. No obstante en los últimos años, la deforestación tropical ha hecho que estos ecosistemas se conviertan en fuente de emisiones de dióxico de carbono (CO2) a la atmósfera. El presente estudio quiso evaluar la distribución de la biomasa aérea (BA) y carbono en relación con la variación altitudinal de los bosques naturales del departamento de Antioquia (Colombia), así como las pérdidas potenciales asociadas con la deforestación, durante el periodo 2000-2007. Para ello se empleó información estructural (diámetro, biomasa aérea) proveniente de 16 parcelas permanentes de 1,0 ha, dentro de las cuales se midió la vegetación leñosa arbórea. Se cuantificó la deforestación a nivel departamental usando imágenes de sensores remotos MODIS para el período 2000-2007. Los resultados evidencian que la BA y los contenidos de carbono en los bosques naturales de Antioquia, presentan una relación inversa con la altitud. La CO2promedio fue 244 ± 63 Mg ha-1 y la tasa de deforestación en el período 2000-2007 fue 25.279 ha año-1. Durante este período se perdieron en total 176.950 ha de bosque natural, con las cuales se emitieron potencialmente a la atmósfera 79.161,29 Gg CO2. En Antioquia posiblemente problemáticas como la deforestación, pueden llegar a destruir considerablemente estos ecosistemas, ocasionando la pérdida de servicios ecosistémicos importantes como el almacenamiento de carbono.

Colombia is a key actor related with the adoption of the relevant UNFCC provisions referred in the context of obtaining result-based payments for REDD+ actions. Since 2012, the Colombian Forest Monitoring System (SMByC, Spanish acronym) has generated wall-to-wall historical information about the deforestation process over the last 27 years at national and regional levels. The SMByC generates a methodology that integrates tools for the preprocessing and semi-automated processing of satellite imagery to detect and quantify the loss of forest cover by deforestation. Also, the SMByC has done an extensive literature review, collecting qualitative and quantitative information to identify how the drivers of deforestation (illicit crops, illegal mining and postconflict scenario) could result in an increased forest lost during a postconflict scenario. Given that Colombia is a country conformed by regions that have differentially socioeconomic and environmental conditions, the study shows how the methods could generate official information and specifies the context of deforestation process of those regions.

The biogeographic origin of species may help to explain differences in average tree height and aboveground biomass (AGB) of tropical mountain forests. After the Andean uplift, small-statured trees should have been among the initial colonizers of the highlands (new cold environment) from the lowland tropics, since these species are pre-adapted to cold conditions with narrow vessels that are relatively resistant to freezing. If the descendants of these small-statured clades continue to dominate tropical highland forests, there will be a high co-occurrence of close relatives at high elevations. In other words, this scenario predicts a systematic decline in tree size, AGB, and phylogenetic diversity with elevation. In contrast, the colonization of Andean forests by some large-statured clades that originated in temperate regions may modify this expectation and promote a mixing of tropical and temperate clades, thereby increasing the phylogenetic diversity in tropical highland forests. This latter scenario predicts an increase or no change of tree size, AGB, and phylogenetic diversity with elevation. We assessed how the historical immigration of large-statured temperate-affiliated tree lineages adapted to cold conditions may have influenced the composition and structure of Andean forests. Specifically, we used 92 0.25-ha forest inventory plots distributed in the tropical Andes Mountains of Colombia to assess the relationship between the phylogenetic diversity and AGB along elevational gradients. We classified tree species as being either "tropical affiliated" or "temperate affiliated" and estimated their independent contribution to forest AGB. We used structural equation modeling to separate the direct and indirect effect of elevation on AGB. We found a hump-shaped relationship of phylogenetic diversity, AGB, and tree size with elevation. The high phylogenetic diversity found between 1,800-2,200 m above sea level (asl) was due to the mixing of highland floras containing many temperate-affiliated species, and lowland floras containing mostly tropical-affiliated species. The high AGB in highland forests, which contrasted with the expected decline of AGB with elevation, was likely due to the significant contribution of temperate-affiliated species. Our findings highlight the lasting importance of biogeographic history on the composition and structure of Andean mountain forests.

Carbon-centric conservation strategies such as the United Nation's program to Reduce CO2 Emissions from Deforestation and Degradation (REDD+), are expected to simultaneously reduce net global CO2 emissions and mitigate species extinctions in regions with high endemism and diversity, such as the Tropical Andes Biodiversity Hotspot. Using data from the northern Andes, we show, however, that carbon-focused conservation strategies may potentially lead to increased risks of species extinctions if there is displacement (i.e., “leakage”) of land-use changes from forests with large aboveground biomass stocks but relatively poor species richness and low levels of endemism, to forests with lower biomass stocks but higher species richness and endemism, as are found in the Andean highlands (especially low-biomass non-tree growth forms such as herbs and epiphytes that are often overlooked in biological inventories). We conclude that despite the considerable potential benefits of REDD+ and other carbon-centric conserva...

Global tropical deforestation continues to occur at high rates despite political attention. National-level forest baselines are being established all over the world to guide the implementation of several policy mechanisms. However, identifying the direct and indirect drivers of deforestation and understanding the complexity of their interlinkages are often difficult. We first analyzed deforestation between 1990 and 2005 at the national level and found an annual deforestation rate of 0.62 %. Next, we performed separate analyses for four natural regions in Colombia and found annual deforestation rates between 0.42 and 1.92 %. Using general linear models, we identified several direct causes and underlying factors influencing deforestation at the national level: rural population density, cattle, protected areas, and slope. Significant differences in deforestation rates and causes were found across regions. In the Caribbean region, drivers of loss are urban population, unsatisfied basic needs, slope, and precipitation and four land use variables (illicit crops, pastures, cattle, and fires). In the Orinoco region, crops are the main driver of forest loss, and in the Amazonian region, deforestation is primarily due to fires related to the colonization front. Policy mechanisms will have to take into account regional patterns to successfully balance development and forest preservation in Colombia.

SOLAP data cubes are a main tool to help on the processing of satellite imagery. This article presents the work developed for adapting an existing SOLAP Data Cube to the current Colombian Protocol for processing satellite images to analyze deforestation. We studied different technological alternatives to support such protocol and extend the capabilities of the Australian data cube to include the whole analysis process. In this way, it is possible for different institutions to produce and consume information to/from the data cube allowing the standardization of such information. In consequence, an institution can generate new results based on previous information generated for another institution, keeping the associated metadata along the whole process. This paper introduces the defined architecture, a first implementation and the first results obtained by IDEAM, the Colombian official institution responsible for the monitoring of deforestation in the country.

The atmospheric correction of remote sensing products is a process frequently used to reduce the reflectivity error produced by the presence of aerosols and other particles in the atmosphere. This process applies linear transformations that converts digital values to values of reflectance. The 6S model is widely used to atmospherically correct the remote sensing products. This solar-radiation based model transforms the image to reduce the noise produced by the different atmospheric conditions. This model is a simulation-based method that requires an initial parameterization given by the at acquisition conditions. This parameterization is comprised by an atmospheric profile, aerosol profile, ground reflectance, geometries, and altitude of the image among others. In this paper, an automatic selection of the parameters using search of parameters is proposed to parameterize the model using as a reference the theoretical signature spectral of tropical forest on Landsat which is assumed to have a low dispersion. Our results show that the configuration with minimum distance is a atmosphere profile of mid-latitude winter, aerosol profile of biomass burning, ground reflectance of green vegetation and Aerosol Optical Thickness of 0.4.

We assessed the expected historical and current speciesrichness of shrubs and trees in the Department of Antioquia,northwest region of Colombia. We used the Fisher´s alpha valueassociated with the pooled dataset of identified species in 16 1-haplots that were used to extrapolate the scaled species richness ofthe Antioquia Province under three different scenarios: 1) the entireregion before deforestation began, assuming an original forestcover of around 92% of the entire province (excluding paramos,rivers, and lakes). 2) The forest cover in 2010. 3) The expected forestcover in 2100 assuming the observed deforestation rate between2000 and 2010 as a constant. We found that, despite relativelylow local and global losses of species, global extinctions in termsof number of species could be dramatically high due to the highendemism and deforestation rates.

Topography is a factor that can significantly affect the diversity and the distribution of trees species in tropical forests. Aniba perutilis, a timber species listed as vulnerable to extinction, is widely distributed in Andean forest fragments, especially in those with highly variable topography. Based on field surveys and logistic regression analyses, we studied the population structure and the effect of highly variable topography on the spatial distribution of this tree in three protected forest fragments in the central Andes of Colombia. Individuals of A. perutilis were mainly found on mountain ridges and hills with gentle slopes; no individuals were found in valleys. Using a species distribution model with presence/absence data, we showed that the available habitat for A. perutilis is significantly smaller than the extension of the fragments and much smaller than the extension of the currently protected areas. Our results have important implications for the conservation ofA. perutilis and likely for other threatened Andean tree species, which can also have locally restricted distributions due to highly variable local topography.

Topography is a factor that can significantly affect the diversity and the distribution of trees species in tropical forests. Aniba perutilis, a timber species listed as vulnerable to extinction, is widely distributed in Andean forest fragments, especially in those with highly variable topography. Based on field surveys and logistic regression analyses, we studied the population structure and the effect of highly variable topography on the spatial distribution of this tree in three protected forest fragments in the central Andes of Colombia. Individuals of A. perutilis were mainly found on mountain ridges and hills with gentle slopes; no individuals were found in valleys. Using a species distribution model with presence/absence data, we showed that the available habitat for A. perutilis is significantly smaller than the extension of the fragments and much smaller than the extension of the currently protected areas. Our results have important implications for the conservation of A. perutilis and likely for other threatened Andean tree species, which can also have locally restricted distributions due to highly variable local topography.

The graph to considered will be in general simple and finite, graphs with a nonempty set of edges. For a graph G, V(G) denote the set of vertices and E(G) denote the set of edges. Now, let Pr = (0, 0, 0, r) ? R4, r ? R+ . The r-polar sphere, denoted by S Pr , is defined by {x ? R4/ ||x|| = 1 ? x ? Pr }: The primary target of this work is to present the concept of r-Polar Spherical Realization of a graph. That idea is the following one: If G is a graph and h : V (G) ? S Pr is a injective function, them the r-Polar Spherical Realization of G, denoted by G*, it is a pair (V (G*), E(G*)) so that V (G*) = {h(v)/v ? V (G)} and E(G*) = {arc(h(u)h(v))/uv ? E(G)}, in where arc(h(u)h(v)) it is the arc of curve contained in the intersection of the plane defined by the points h(u), h(v), Pr and the r-polar sphere.