Patterns and Trends of Forest Loss in the Colombian Guyana

Abstract

Spatial patterns of tropical deforestation and fragmentation are conditional upon human settlement characteristics. We analyze four different human occupation models (indigenous, colonist frontier, transition and established settlement) in the Colombian Guyana Shield at three different times : 1985, 1992 and 2002, and compared them for: (1) deforestation rates; (2) the amount of forest as classified according to a fragmentation pattern (interior forest, edge forest, perforated forest and forest patch); (3) various fragmentation metrics using repeated measures analysis of variance; and (4) potential future deforestation trends though the implementation of a spatially explicit simulation model. The indigenous and colonist frontier occupation models had low rates of deforestation (0.04%/yr), while the wellestablished settlement occupation model had the highest rate (3.68%/yr). Our results indicate that the four occupation models generate three deforestation patterns: diffuse, which can be subdivided into two subpatterns (indigenous and colonist), geometric (transition) and patchy (established settlement). The area with the established settlement model was highly fragmented, while in the transition occupation area, forest loss was gradual and linked to economic activities associated with the expansion of the agricultural frontier. The simulation of future trends revealed that indigenous and colonist areas had a constant, albeit small, loss of forest covers. The other models had a deforestation probability of 0.8 or more. Overall, our results highlight the need for new and urgent policies for reducing forest conversion that consider intraregional variability in human occupation linked to differences in land-use patterns.Abstract in Spanish is available in the online version of this article.

Tropical forest cover dynamics for Latin America using Earth observation data: a review covering the continental, regional, and local scale

“…Similar to regional studies, the majority of the articles were carried out within the Brazilian region (75% of the studies), mainly covering the states of Mato Grosso, Rondônia, Pará, and Paraná (Di Maio Mantovani and Setzer 1997; Alves et al 1999;Ichii, Maruyama, and Yamaguchi 2003;Ferraz et al 2005;Morton et al 2006;Zaloti et al 2006;Brown et al 2007;Wynne et al 2007;Souza and Verburg 2010;Yoshikawa and Sanga-Ngoie 2011). Local studies were often aiming at understanding the influences of anthropological activities impacting the forest, giving particular attention to agricultural expansion and urbanization (Sierra 2000;Nagendra, Southworth, and Tucker 2003;Armenteras et al 2006;Morton et al 2006;Alves et al 2009;Pinto-Ledezma and De Centurión 2010;Dávalos et al 2011;Rodríguez et al 2012). Unlike the global and regional scale, local studies more often address forest degradation (Almeida- Filho and Shimabukuro 2002;Souza et al 2003 1975-2000and 1985-2005.…”

“…Different from regular temporal intervals, other studies applied irregular time intervals between images acquired. Imagery was selected according to the aim of the study including up to seven time steps over the analysis (Sanchezazofeifa et al 2002;Ichii, Maruyama, and Yamaguchi 2003;Armenteras et al 2006;Rodríguez et al 2012;Bianchi and Haig 2013;Lu et al 2013). For example, Viña, Echavarria, and Rundquist (2004) analysed deforestation drivers and rates over the Colombian and Ecuadorian Amazon using Landsat images from 1973, 1985, and 1996, thereby comparing the deforestation rates obtained for each of these years.…”

Different times, same story: Native forest loss and landscape homogenization in three physiographical areas of south-central of Chile

“…The general trends reported for native forest loss, local spatial patterns and drivers of change mainly result from human settlement, which is ultimately related to the predominant biophysical conditions (Rodríguez, Armenteras, Retana, & Molowny-Horas, 2011). In general, population pressure and shifting areas of cultivation are the main factors for deforestation (Geist & Lambin, 2002).…”

“…According to Echeverría et al (2012), the current state of landscape conservation may strongly influence patterns of land use change and the predominant drivers of that change. We hypothesized that the physiographical conditions and the historical phases of the landscape will influence the intensity of landscape change (Altamirano, Aplin, et al, 2013;Altamirano, Salas, et al, 2013;Rodríguez et al, 2011;Rodriguez, Armenteras, & Retana, 2012). In other zones of southern central Chile it has been shown that land cover change is heterogeneous across time and space, as significant relationships have been found between the spatial distribution of land cover types and different biophysical variables; these relationships also change over time (Echeverria, Coomes, Hall, & Newton, 2008;Nahuelhual, Carmona, Lara, Echeverría, & Gonz alez, 2012;Schulz, Cayuela, Rey Benayas, & Schr€ oder, 2011).…”

Nueva especie de Lonchorhina (Chiroptera: Phyllostomidae) de Chiribiquete, Guayana colombiana

“…The inselbergs are described as outstanding biomas consisting of huge, dark black, rocky boulders and hills with a characteristically dome-like appearance, rarely more than 300-400 m high, but of variable horizontal extension" (Gröger and Huber 2007). A very important feature of the Guayana region, besides its insular distribution, is its remarkable low content of soil nutrients, which pose a challenging environment to its high endemic biota (Cortés and Franco 1997, Hollowell and Reynolds 2005, Rodríguez et al 2012. The unique morphological features of Lonchorhina species, especially those related to echolocation, might be associated to their life in such a prohibitive and astonished landscape.…”