Elsevier

Applied Geography

Volume 91, February 2018, Pages 99-110
Applied Geography

Environmental predictors of forest change: An analysis of natural predisposition to deforestation in the tropical Andes region, Peru

https://doi.org/10.1016/j.apgeog.2018.01.002Get rights and content

Highlights

  • Deforestation patterns are strongly linked to natural landscape characteristics.

  • Soil type and rainfall are the most important natural deforestation determinants.

  • The relation between deforestation and coca production and gold mining was examined.

  • Protected areas are usually created in environmentally undesired locations.

Abstract

The spatial patterns of deforestation are usually non-randomly distributed across the landscape. While anthropogenically driven processes are often addressed in land-use regulation policies and deforestation research, less attention is given to the environmental factors that influence tropical deforestation. This study investigates to what extent climate conditions (temperature and precipitation) and biophysical landscape characteristics (elevation, slope, soil type, forest type, and distance to rivers) facilitate or mitigate deforestation processes in Peru's tropical Andes. A Random Forest regression model was constructed for the entire Peruvian tropical Andes, and separate models were developed for some of the known direct deforestation drivers in the region (coca production, gold mining, and land-use by indigenous and non-indigenous communities). Soil type and precipitation were identified as the most important deforestation predictors when the entire Peruvian tropical Andes was considered, whereas distance to rivers was associated with deforestation by mining activities, and elevation and temperature with coca cultivation areas. Using the regression results, a Random Forest classification model was constructed to locate areas where the composition of environmental factors could either facilitate or mitigate deforestation processes. It was found that almost 85% of the forests classified as having high to very high probability to deforestation were located outside current protected areas. In order to increase conservation impacts, the results suggest that greater consideration should be given to the distribution of environmental factors when designing land-use regulation policies and establishing protected areas.

Introduction

Ongoing processes of forest destruction across tropical regions pose a major threat to biodiversity, climate stability and the functioning of biogeochemical and hydrological cycles (Bonan, 2008, Malhi et al., 2008). In spite of the worldwide recognition of this environmental problem and the implementation of manifold initiatives to halt further reduction of tropical forest areas, the rates of deforestation in the tropics have remained consistently at high levels (Achard et al., 2014, Sloan and Sayer, 2015). Much attention goes to the tropical forest ecosystems in Central and South America, which harbor some of the world's greatest amounts of species diversity (Poveda et al., 2011, Ribeiro et al., 2011, pp. 405–434) and constitute the largest portion of the global terrestrial carbon sink (Pan et al., 2011). Between 2000 and 2010, the extent of forest cover in Central and South America shrunk by approximately 55,000 km2 per year, with important deforestation hotspots located in northern Argentina, southeastern Bolivia, western Paraguay and the Brazilian Amazon (Aide et al., 2013). According to recent land-use change scenarios for the Neotropics (Soares-Filho et al., 2013), in particular the lowland Amazon basin and forests located at the Andean foothills will experience extensive forest losses in the future, whereas forest recovery could be expected in the highland forests of the Andean mountain range (Middendorp et al., 2016, Sanchez-Cuervo and Aide, 2013a). These dynamics of Neotropical forest cover change will largely shape the future well-being of people relying directly on forest ecosystem services.

In the last decades, substantial efforts have been made by researchers to determine why forest change happens and why the patterns and rates of forest change vary across the landscape (Rudel, 2007). An important contribution to the deforestation literature is the work by Geist and Lambin (2002), which conceptualizes the dynamics between fundamental social processes such as population changes, and human activities or actions at the local level with direct impacts on forest cover such as logging and agricultural expansion. Proximate causes and underlying driving forces typically relate to anthropogenic systems, however, environmental factors are also recognized to play a crucial role in the process of forest cover change. Geist and Lambin (2002) reviewed 152 subnational case studies from the tropical belt, out of which a third reported a link between deforestation and factors associated with the biophysical environment, including a range of landscape attributes and climate variables. The effect of these environmental factors is linked to human behavior at the local level, as they set the necessary conditions for land-use change processes to occur, and place physical thresholds on the types of land-use practices that are feasible in a region (Aide et al., 2013). While this emphasizes the importance of considering landscape elements and climate conditions at local scales, the mainstream deforestation literature is particularly oriented towards analyzing the political, economic, and social context in which forest change processes occur (Jusys, 2016, Lambin et al., 2001, Robinson et al., 2014, Rudel et al., 2009).

Nonetheless, a great variety of models have been developed throughout the years to describe the role of the natural environment in the deforestation process (Busch and Ferretti-Gallon, 2017, Kaimowitz and Angelsen, 1998). The environmental variables commonly included in models relate to land accessibility, land suitability and climate variability. Landscape characteristics that provide natural access routes to forests include rivers and lakes (Salonen, Toivonen, Cohalan, & Coomes, 2012), especially in areas where roads and other infrastructure is scarce (Armenteras, Rudas, Rodriguez, Sua, & Romero, 2006). Furthermore, forests located along the coastline that were better accessible were found to be subjected to more deforestation compared to mainland forests (Rudel & Roper, 1996). Elevation and slope gradients have been associated with forest accessibility and deforestation as well (Bax, Francesconi, & Quintero, 2016), although they particularly determine the suitability of the land for productive activities (Pope et al., 2015). Higher sloped terrain is less attractive for agriculture, given that harvests are generally lower (Barrowclough et al., 2016) and working the land requires greater efforts and resources (Grau, Kuemmerle, & Macchi, 2013). The relationship between deforestation and topography is likely to become weaker through time when low-lying lands become scarcer and exhausted, leaving people no other choice but to move to steeper areas. Deforestation induced by the suitability of the land is also determined by the quality of the soil, mainly within the context of agricultural production (Laurance et al., 2002), and by forest type (Chowdhury, 2006), given the potential preferences of loggers for tree species with high economic value (Asner et al., 2005). Climate also seems to affect deforestation through local variations in precipitation, temperature, and dry season severity. Precipitation and dry season severity can either have a hindering or an enabling effect: less rainfall results in dryer forests which are easier to burn (Aragao et al., 2008) while deficit or excessive rainfall tends to reduce crop yields (Grau, Gasparri, & Aide, 2005). On the other hand, areas characterized by moderate local temperatures provide desirable conditions for establishing human settlements, which transform the natural landscape (Armenteras, Rodríguez, Retana, & Morales, 2011).

Given that the tropical Andes region is characterized by a great variation in altitude, forest structure, temperature and rainfall patterns, the way in which land cover transformations are being undertaken could be related to these environmental attributes. A better understanding of nature's influence on deforestation decision making (here defined as the decision of land-managers to conserve or convert forest) is needed, as it is currently not adequately addressed in land-use regulation policies (Joppa and Pfaff, 2009, Miteva et al., 2012). However, studies specifically focusing on the environmental dimensions of deforestation are scarce. Generally more attention is given to human-related drivers and causes. To the best of our knowledge, the work by Rolett and Diamond (2004) may be the best known study that focuses on the effect of predisposing environmental factors on forest transitions. Hence, understanding the biophysical and climate context of forest cover change in the highly diverse landscape of the Andean mountains could advance our understanding of montane forest management. Furthermore, most studies on deforestation in the Neotropical region focus on lowland Amazon ecosystems, while information on Andean ecosystems remains limited (Armenteras et al., 2011, Zuluaga and Rodewald, 2015). In particular, very few studies have analyzed deforestation practices in the Peruvian Andes region. Current rates of forest cover change and hotspot locations in the Peruvian Andes are not provided in the scientific literature, and the drivers associated with these changes are not clearly understood (Robiglio, Armas, Silva Aguad, & White, 2014). Nonetheless, the tropical Andes have been identified as the most critical biodiversity hotspot on the planet in terms of plant and vertebrate species richness (Myers, Mittermeier, Mittermeier, Da Fonseca, & Kent, 2000), which emphasizes the importance of investigating deforestation dynamics in this region. More specifically, the objectives of this study were to 1) identify and examine the environmental factors that facilitate or mitigate deforestation in the tropical Peruvian Andes; 2) analyze the influence of these environmental factors on some of the known direct deforestation drivers in the region; and 3) map the areas where the natural landscape facilitates or mitigates deforestation.

Section snippets

Study area

Peru's tropical forest region can be disaggregated into the lowland Amazon consisting of humid forests at low elevations, the northern coast region consisting of dry forests, and the tropical Andes region consisting of sub-tropical forests located along the eastern slopes and valleys of the Andean mountain range. The Peruvian tropical Andes are located between coordinates 3˚5′10 South, 79˚1′15 West, 14˚29′24 South and 68˚49′37 West, with most of the forests located at elevations ranging from

Results

The merge of the MINAM land cover map with the Global Forest Watch and Terra-i datasets yielded a layer representing deforestation in the Peruvian tropical Andes until the year 2017 (Fig. 2). On the basis of this layer, the total extent of cleared forests equaled 44,200 km2, which corresponds to 23% of the studied area. Between 2011 and 2017, more than 1150 km2 of forests were converted into other land-uses, yielding an annual deforestation rate of 19,300 ha per year (0.1%). This implies that

Discussion

It is well known that the geophysical variation in topography, climate and natural access routes such as rivers significantly influences the spatial patterns of human population and settlement distribution (Lung et al., 2013, Small and Cohen, 2004). With respect to the Andes, archeological evidence points to a very long history of human occupation of the subtropical Andean forests, especially at elevations below 1500 m.a.s.l. where environmental conditions are more conducive to agricultural

Conclusions

Using the tropical Peruvian Andes as a case study, we provided an example of how spatially explicit models can be used to characterize localized deforestation processes at the landscape level. This study applied Random Forest to examine the spatial patterns of deforestation and explore which types of deforestation activities are feasible throughout the region. In contrast to prior deforestation modeling studies, we specifically examined to what degree the structure of the natural landscape

Conflicts of interest

None.

Acknowledgement

This work was supported by funding provided by Universidad de Ciencias y Humanidades.

References (92)

  • T. Lung et al.

    Human population distribution modelling at regional level using very high resolution satellite imagery

    Applied Geography

    (2013)
  • A.S. Nanni et al.

    Redistribution of forest biomass in an heterogeneous environment of subtropical Andes undergoing agriculture adjustment

    Applied Geography

    (2015)
  • S. Oliveira et al.

    Modeling spatial patterns of fire occurrence in Mediterranean Europe using Multiple regression and random forest

    Forest Ecology and Management

    (2012)
  • R. Porro et al.

    Forest use and agriculture in Ucayali, Peru: Livelihood strategies, poverty and wealth in an Amazon frontier

    Forest Policy and Economics

    (2015)
  • B.E. Robinson et al.

    Does secure land tenure save forests? A meta-analysis of the relationship between land tenure and tropical deforestation

    Global Environmental Change

    (2014)
  • T.K. Rudel

    Changing agents of deforestation: From state-initiated to enterprise driven processes, 1970–2000

    Land Use Policy

    (2007)
  • M. Salonen et al.

    Critical distances: Comparing measures of spatial accessibility in the riverine landscapes of Peruvian Amazonia

    Applied Geography

    (2012)
  • S. Sloan et al.

    Forest Resources Assessment of 2015 shows positive global trends but forest loss and degradation persist in poor tropical countries

    Forest Ecology and Management

    (2015)
  • F. Achard et al.

    Determination of tropical deforestation rates and related carbon losses from 1990 to 2010

    Global Change Biology

    (2014)
  • F. Achard et al.

    Determination of deforestation rates of the world's humid tropical forests

    Science

    (2002)
  • T.M. Aide et al.

    Deforestation and reforestation of Latin America and the Caribbean (2001–2010)

    Biotropica

    (2013)
  • N.L. Alvarez-Berríos et al.

    Global demand for gold is another threat for tropical forests

    Environmental Research Letters

    (2015)
  • L.E.O. Aragao et al.

    Interactions between rainfall, deforestation and fires during recent years in the Brazilian Amazonia

    Philosophical Transactions of the Royal Society of London B Biological Sciences

    (2008)
  • D. Armenteras et al.

    Understanding deforestation in montane and lowland forests of the Colombian Andes

    Regional Environmental Change

    (2011)
  • G.P. Asner et al.

    Selective logging in the Brazilian Amazon

    Science

    (2005)
  • G.P. Asner et al.

    Elevated rates of gold mining in the Amazon revealed through high-resolution monitoring

    Proceedings of the National Academy of Sciences

    (2013)
  • M. Barrowclough et al.

    Conservation agriculture on steep slopes in the Andes: Promise and obstacles

    Journal of Soil and Water Conservation

    (2016)
  • G.B. Bonan

    Forests and climate change: Forcings, feedbacks, and the climate benefits of forests

    Science

    (2008)
  • L. Breiman

    Random forests

    Machine Learning

    (2001)
  • S.B. Brush

    The natural and human environment of the central Andes

    Mountain Research and Development

    (1982)
  • J. Busch et al.

    What drives deforestation and what Stops It? A meta-analysis

    Review of Environmental Economics and Policy

    (2017)
  • R.R. Chowdhury

    Driving forces of tropical deforestation: The role of remote sensing and spatial models

    Singapore Journal of Tropical Geography

    (2006)
  • G. Di Lallo et al.

    REDD+: Quick assessment of deforestation risk based on available data

    Forests

    (2017)
  • T.D. Dillehay et al.

    Early Holocene coca chewing in northern Peru

    Antiquity

    (2010)
  • M. Dourojeanni

    Environmental impact of coca cultivation and cocaine production in the Amazon region of Peru

    Bulletin on Narcotics

    (1992)
  • C.L. Erickson

    Neo-environmental determinism and agrarian ‘collapse’in Andean prehistory

    Antiquity

    (1999)
  • E.Z. Escamilla et al.

    Environmental impacts of bamboo-based construction materials representing global production diversity

    Journal of Cleaner Production

    (2014)
  • A. Etter et al.

    Patterns of landscape transformation in Colombia, with emphasis in the Andean region

    AMBIO: A Journal of the Human Environment

    (2000)
  • J.S. Evans et al.

    Modeling species distribution and change using random forest. Predictive species and habitat modeling in landscape ecology

    (2011)
  • FAO-Unesco

    Soil map of the world

    (1990)
  • S.E. Fick et al.

    WorldClim 2: New 1-km spatial resolution climate surfaces for global land areas

    International Journal of Climatology

    (2017)
  • M. Finley-Brook

    Indigenous land tenure insecurity fosters illegal logging in Nicaragua

    International Forestry Review

    (2007)
  • W. Francesconi et al.

    Modeling for management: A case study of the cañete watershed, Peru

  • H.J. Geist et al.

    Proximate causes and underlying driving forces of tropical deforestation: Tropical forests are disappearing as the result of many pressures, both local and regional, acting in various combinations in different geographical locations

    BioScience

    (2002)
  • H. Grau et al.

    Agriculture expansion and deforestation in seasonally dry forests of north-west Argentina

    Environmental Conservation

    (2005)
  • M.C. Hansen et al.

    High-resolution global maps of 21st-century forest cover change

    Science

    (2013)
  • Cited by (0)

    View full text