Agroforestry as an Alternative to Shifting Cultivation in the Amazon: a Socio- Environmental Approach
From a socio-environmental point of view (quotation), the Amazon basin is the most important extension of constant tropical forest in the world, including nearly 40% of the total surface of the tropical rainforests distributed along nine countries in South America (Laurance et al. 2001; Cerri et al. 2007), and representing 80% of the total existing tropical forests in the Neo-tropics (quotation). Its impact at a global level has been attributed to its role in the maintenance of biodiversity and of hydric cycles, as well as to its role in the terrestrial carbon storage (Laurance et al. 2001). Currently, investigations on ecosystem patterns and processes in these forests are becoming interesting as means for facing the general worries derived from the ongoing changes regarding the use of land, which is cause to atmospheric emissions of carbon and biodiversity loss (Houghton et al. 2002; Betts et al. 2008), not to mention the possible consequences, including forest degradation and the decline in the quality of life of the locals: both of which have been poorly examined so far.
Compared to other tropical forests in different latitudes in the world, the Amazon is typically known as a bio- geographical region representing a high biological diversity (Barthlott et al. 1997), also, as a place where numerous living species have been domesticated for diverse purposes -such as a source of food-, and finally, as a place where old crop-growing exchange practices have existed among indigenous populations and for millions of years (Pipermo, 2009; Arroyo-Kalin, 2012). Likewise, the Amazon is potentially an efficient plant of carbon sequestration, providing the world with an environmental service (Kareiva & Ruckelshaus, 2012; Parrota et al 2012), by storing up to 86 carbon Pg, both below and over the soil (Betts et al. 2008), with Brazil representing its largest extension area with more than 60% of the whole basin: a strategic country for biodiversity conservation purposes and for carbon storage (FAO, 2010). However, there is still little information on the patterns related to the production of ecosystem goods and services at a regional level, and little information on their impact over the quality of life of the surrounding indigenous and non-indigenous communities.
This basin region is recognized as the largest area inhabited by indigenous populations in the tropics, with about 350 different indigenous groups (Porro et al 2012), who are living in forests that have been a source of different goods and services, ever since the past 13000 millions of years (Roosevelt, 2013), according to archeological evidence mainly obtained through small- scale farming practices, food gathering, hunting and construction materials (Pipermo, 2009; Arroyo-Kalin, 2012; Roosevelt, 2013). Consequently, these ecosystems have played a fundamental role in the preservation of numerous indigenous civilizations that keep using the same ancestral patterns of land use, even if many of those human groups have also had a strong influence coming from the Western civilization (Porro et al 2012; Roosevelt, 2013;). Moreover, there are several studies explaining how different factors directly influence deforestation in the Amazon, according to the analysis of biophysical patterns and demographical processes such as population’s growth, immigration and colonization of new indigenous and non-indigenous settlements via new road networks, and thus, through a larger expansion of the basin’s agricultural frontier (Laurence et al 2002; Nepstad et al 2009; Porro et al. 2012; Boucher et al 2013), given the continuing demand on goods and services for domestic and commercial purposes.
There is evidence on how the continuous changes in land use during the last years are producing transformations in the structure and functioning of the Amazon ecosystems (Laurance et al. 2001; Laurance 2004; Nobre & Borma, 2009), which, at the same time, has a considerable negative impact on the human settlements (Porro et al. 2012; Boucher et al 2013). Accordingly, deforestation of Amazon forests by means of the establishment of agricultural systems in indigenous and non-indigenous communities in constant growth, is also causing a greater pressure on the forests, given the enlargement of the agricultural frontier and the increase of the production yield serving domestic demands, as well as local, and even, national markets (Porro et al. 2012; Boucher et al 2013). Besides the areas dedicated to livestock farming and extensive soy crops (Boucher et al 2013), the types of agricultural practices in the region have been characterized as shifting (log, slash and burn), consisting in small area deforestation of primary and secondary forests, as part of the necessary land preparation for the establishment of annual crops –mostly-, for short periods of time (2-3 years), due to the diminished soil fertility (Arroyo-kalin, 2012). For this reason, the conservation and sustainable management of the forests in the Amazon has become so important during the last decade, as ways to facing the need to prevent and reduce the effects of the accelerated deforestation and forest degradation caused by the different changes in the ways of using land throughout the ecological history of the basin (Nepstad et al 2009; Porro et al 2012; Boucher et al 2013).
The future of the conservation of the Amazon basin depends a lot on the strategies and actions oriented to optimize the use and sustainable management of ecosystem goods and services, with agriculture being one of the main direct causes for deforestation; and such strategies ought to guarantee a simultaneous production of environmental, social and economic impact (Nepstad et al 2009; Boucher et al 2013). This is why, by searching a balance between development and conservation, Agroforestry has become into a proposal of a sustainable agricultural model for the region (Porro et al 2012), which has also recently been recognized as a model of Intelligent Climate Agriculture that could contribute to the increase of the system’s productivity, so that means of livelihood are produced for the current and future generations, in so far as greenhouse gas emissions are reduced (FAO, 2013). However, there is no proper analysis fully reconciling Agroforestry with biodiversity conservation and carbon sinks, as fundamental goods and services for the well-being of the locals, and particularly, as an alternative to reduce the pressure represented in the use and management of the forests.
Presently, agroforestry systems in protected areas in Brazil represent an important alternative involving environmental, social and economic aspects, to help tracing and maintaining a sustainable management of the forests in small rural indigenous properties (Soares-Filho et al 2010; Oliveira-Neto, 2012; Porro et al 2012), which would represent a point of reference and an alternative as an administration model for other countries making part of the Amazon basin; even if certain types of use of land are recognized to be producing significant impact on forest loss (soy, livestock, mining, selective logging). Hence, Agroforestry as an alternative to the model of shifting cultivation may represent a suitable option for the conservation and management of the primary forests, along with the different stages of succession- regeneration (secondary forests), which are important for the recovery and maintenance or increase of the existing biodiversity and of the carbon sinks, as means to provide the region and the globe with an important service (Nair et al 2009; Sougata & Shibu 2012; Parrota et al 2012). Furthermore, Agroforestry may help small indigenous and non- indigenous farmers in the Amazon region, by providing them with an alternative to harvest agroforestry products and contribute with their own food security, both at domestic and local levels, so as with an alternative to create income by means of placing their products on the market in local agro-food networks, or organized national networks.
So far, there is only an extensive review on the impact caused by the management of the forests and the land, both on biodiversity and carbon, where the applicability of the proposed measures to reduce the emissions due to deforestation and forest degradation were examined (Parrota et al. 2012). However, there is no comprehensive proposal which would simultaneously analyze the potential elements and the existing relations between Agroforestry as a sustainable alternative to manage the Amazon forests, and biodiversity and carbon -as important sources of environmental goods and services-, given the continuous changes in the use of land, caused by deforestation practices carried out with the purpose of establishing shifting farming systems, which at the same time, bring as a consequence the fragmentation of the landscapes and the degradation of areas at diverse extents. To address the need to give alternatives to increase the efficiency of the initiatives of management and conservation of biodiversity and carbon in vulnerable areas, the objective in here is to develop a comprehensive analysis of the potential social and environmental impact that Agroforestry could bring to the Amazon basin.
Colonization and Occupation Patterns in the Amazon
There have been different aborigine indigenous groups in the Amazon basin that have regarded their territories as the place where diverse social and cultural relations occur, according to the natural traits of each settlement (Pipermo, 2009; Arroyo-Kalin, 2012; Roosevelt, 2013). Subsequently, given the broad cultural indigenous spectrum and the different types of existing forests within the basin, multiple types of use and management of ecosystem goods and services provided by the woods have been recognized (quotations). This has barely been studied so far. Nevertheless, the gathering of non-timber forestry products and the food production carried out with shifting agriculture systems, as main traditional local means of livelihood, are the general pattern at a local level (Arroyo-Kalin, 2012; Roosevelt, 2013). These ways of using the land have been predominant in the tropical forests at a global level, particularly when used by indigenous societies that have developed strategies to adapt to their surrounding environmental conditions (Barton et al., 2012)
According to archeological evidence, the tropical rain forests have been exposed to a constant pressure coming from deforestation processes and locals’ subsistence practices, during long periods of time; conversely, during the last decades, the forest loss rates have significantly increased, as a result of shifting cultivation, livestock framing and timber extraction practices (Barton et al., 2012). Similarly, it has been well documented that the Amazon occupation began back in the Holocene, following ancient evidence on the use of fire by means of establishing agriculture systems (vegetal carbon and pollen in soil samples), even if it has been difficult to understand its complexity (Pipermo, 2009; Arroyo-Kalin 2010; Arroyo-kalin, 2012). In this respect, Arroyo-kalin (2012), undertook an examination through which the importance of Shifting Cultivation was explained and brought to recent discussions on Pre-Columbian Amazon, specifically by using evidence findings on Pre-Columbian anthropogenic soils that have helped re-evaluate how the speed and heterogeneity of regional crop domestication (specific growing practices) might have influenced the history of fire in the Amazon. Hence, in this context, it would become more complex to understand the effects of the use of the land along the history on possible future Amazon forests.
Only ever since last century, after 1950, a complex process of transformation of the agricultural, environmental, social and cultural context of the Amazon basin began to be carried out, while there were changes in agricultural policies through a migration program in some countries of the basin, mainly Brazil and Venezuela (Llambi & Llambi, 2000; Diniz et al 2013). Agricultural reforms in these countries were oriented to the widening of the agricultural frontier, in order to increase the levels of production, and answer to the national demands, in the same way that new territory occupation was stimulated with geopolitical purposes. However, there is little evidence on how these accelerated processes of demographical expansion and historical occupation of the diverse indigenous communities in the basin took place, as well as there is Little evidence on the subsequent processes of immigration of the non-indigenous populations and emigration of indigenous populations towards other communities.
Also, the first impacts caused by the influence of the Western civilization on the patterns of the land and forestry resources’ use have not been taken into account. Anyway, historical patterns of occupation of the indigenous and creole populations are thought to have a different history in each eco-region, given the current political and economic development processes in each country making part of the basin. For instance, in some of the states in the Brazilian Amazon, evidence has been found on occupation changes through regressive models for deforestation, which reveals important changes in the patterns of human occupation (Laurance et al 2002; Espindola et al. 2012),
Nevertheless, regardless of the historical processes of occupation, and of the different development processes that have occurred at a regional scale, there is currently a prevailing tendency towards settlement of indigenous populations in specific communities, besides a growth and expansion of those communities towards other regional settlements. In this way, such social and demographic processes have also brought as a consequence, a negative impact over the ecosystem goods and services that these local settlements demand, maintaining a constant rate of deforestation as a result of the establishment of shifting agriculture systems that have been increased at the same speed as local settlements. Also, because of the low fertility of the soil, the whole situation has forced the locals to settle in new communities (Oliver, 2001; Arroyo-Kalin, 2012). Anyway, the exact strength of the existing relation between forest sustainability and nomadic indigenous populations’ emigration, or between population’s growth and agriculture frontier’s expansion is not well known.
In this way, several researchers point out that the structure and dynamics of the ecosystems and human settlements have a significant effect on the quality of life of the locals. This could be evaluated through social and environmental quality of life indicators (Contreras & Cordero, 1994; Romero-González, 2011), so that those tendencies and effects that have been produced by the changes in the use of land, mainly because of deforestation, could be better understood. Such social and ecological processes have produced a greater dependency on food sources, both local –from traditional slash and burn systems-, and from outside -given the influence of the Western civilization-, which altogether, have simultaneously been leading to a massive change in life strategies of the ethnic groups.
Deforestation Patterns and Dynamics
There are several studies that explain some ideas about influencing factors over some regions in the Amazon basin where deforestation takes place, mainly developed at a local level in some states in Brazil, but that have had a difficult time finding explanations on the dynamics of the use of land in terms of time and place at a regional level. Several researchers have developed methods and models to estimate how deforestation has been influenced by the changes in the use of land in the Amazon, based upon environmental, cultural, social and economic criteria, as well as on rural development policies. For these criteria, different types of factors that may synergistically have an impact at a local level were selected, and in some cases, their relative importance and changes through time were indicated (Laurence et al. 2001; Laurence et al 2002; Perz & Skole, 2003; Margulis 2004; Soares-Filho et al. 2006; Boucher et al. 2009; Nepstad et al. 2009, Arroyo-Kalin, 2012; Espindola et al. 2012; Diniz et al 2013; Verburg et al., 2014). The most part of these changes have been the result of a combination of factors, some of which could be directly or indirectly connected to deforestation and further agriculture activities to meet domestic needs, or those of different types of markets.
In this respect, a first approach consisting of some environmental criteria that influence deforestation in some regions in the Amazon, has included the examination of the effects of low precipitations, severe dry seasons with long periods of hydric deficit and low-fertility soil over the vulnerability of the deciduous and semi-deciduous forests. This vulnerability, at the same time, influences these forests’ ability to regenerate after disturbances (Laurence et al 2002). Similarly, anthropogenic fire is becoming into a more significant cause of forest degradation, especially in those spots with higher deforestation and fragmentation levels (Laurance et al., 2001). For this reason it is presumed that Southern and South-eastern regions in the Amazon would be most vulnerable to the incidence of anthropogenic fire, given the greater proportion of deforested areas and climatic conditions, including low levels of precipitation and significant dry periods.
Recently, Espindola et al. (2012) have undergone a complete study analyzing the dynamics of the use of agriculture land, within three states in the Brazilian Amazon (Rondonia, Mato Grosso e Pará), based on a remote sensors assessment and a data base obtained throughout two separated years (1996 y 2006), considering different factors such as market accessibility, public policies, agricultural structures and environment. Also, Margulis (2004) presented an econometric model for the analysis of the occupation in the Brazilian Amazon, by quantifying the space and time rapports of the first agriculture activities. In this study, a variety of social and economic indicators of the potential social benefits associated with the deforestation processes and the land occupation were assessed. In the same manner, Perz y Skole (2003) developed a secondary forest distribution model in the Amazon basin, by using social indicators as means of exploratory factors to explain the effects of the human settlements and the traditional activities. The positive effect of these settlements was shown in a considerable space variation between different regions.
High rates of immigration and intrinsic population growth have been considered as social factors causing the changes in the use of land in the Amazon, mainly through agriculture, for the non-indigenous population in the Brazilian Amazon raised to approximately 2 to 20 millions of people, ever since 1960, as a consequence of immigration from other regions in Brazil (Laurance et al., 2001; Diniz et al 2013).
Space patterns for forest loss have been changing, back from the previous decade until today, even if those areas with larger rates of deforestation happen to be located all over the eastern and southern margins of the basin, between the states of Pará, Mato-Grosso and Rondonia, considered to be ‘hot zones’ for deforestation (Laurance et al., 2001; Espindola et al. 2012; Diniz et al 2013; Porro et al 2012; Verburg et al., 2014). Nonetheless, the widening of the road networks, and the paving of roads, that facilitate the occupation of new areas, is one of the main factors that explain why deforestation is slowly expanding towards the central zone of the Amazon (Soares-Filho et al. 2006; Soares-Filho et al 2010; Verburg et al., 2014). According to the description of such deforestation factors, it is important to mention that the paving of several roads crossing the Amazon biome is allowing the transportation of agroforestry products towards European and Asian markets to occur, as well as, providing the local soy farmers with a better access to the international markets, while simultaneously promoting an increase in immigration towards those same areas with a larger level of deforestation (Soares-Filho et al. 2006; Boucher et al 2009; Verburg et al., 2014)
On the other hand, according to (Laurance et al., 2001), the selective logging with industrial purposes and the mining had been considerably increasing through the expansion of road networks, which also led new farmers and locals to access the primary forests. In this same sense, following Soares-Filho et al. (2006), there are other important factors that have influenced the Amazon deforestation, like road proximity, indigenous reservations and proximity to the urban centers. Moreover, Espindola et al. (2012) found significant changes depending upon the time, in factors like distance to the roads, number of settled families and indigenous lands; however, factors like the distance needed to cover in order to extract wood, the distance to the rivers, protected areas and the humidity index did not change their influence between 1997-2007. The distance to the roads had a stronger influence in 1997 compared to 2007, which indicates that the tendency to deforestation along the roads dropped, while previous studies pointed that the distance to get to the roads is one of the main determining factors in deforestation (Laurance et al., 2001; Laurance et al., 2004). Still other studies indicate that there are other more important factors besides the distance to the roads (Espindola et al. 2012).
In the Brazilian Amazon, deforestation rates are between 1,1 and 2,9 million hectares a year. The total area affected by deforestation has reached approximately 85 million hectares, that is, around 14% of the total surface in the Brazilian Amazon (INPE, 2013). Nevertheless, according to Nepstad et al (2009), there are promising strategies to reduce the levels of deforestation in the basin, that along with the latest efforts from the government, have led to its annual reduction at a 79% between 2005 and 2013 (INPE, 2013). In the same way, the protected area network was enlarged by 1,26- 1,82 million additional km2 containing an in all 51% of the resting area of forests in the region (Soares-Filho et al 2010). Consequently, the important reduction of deforestation levels during the past years, has taken place despite the continuous pressure exerted by the use of land, specially related to the threatening expansion of the areas devoted to soy plantations and livestock farming in Brazil, due to the strong demand of the national and international markets and the high economic profitability of such activities (Soares-Filho et al. 2006; Nepstad et al 2006; Boucher et al 2009; Verburg et al., 2014).
Clearly, in order to control deforestation coming from different massive activities within the Amazon basin, a larger effort for the adjustment, conciliation and rigorous implementation of agriculture policies of rural development and conservation will be needed, particularly for the management of extensive livestock farming systems, soy plantations to meet the demands of the national and international markets, as well as other activities such as mining and selective logging for industrial purposes. Thus, it would not be irrational to suppose that while the current pattern of land use is maintained, with expanding possibilities, the same vicious circle of forest degradation will continue to successively take place, along with everlasting ecological consequences that would affect the resilience of the ecosystems, which at the same time, would mean a loss in biodiversity and carbon sinks (Thompson et al 2009; Thompson et al 2013).
Even when the relative impact created by the shifting cultivation remains unknown as a generalized pattern of land use in all the basin, compared to other types of use of land at a regional level, it is at least well known that it remains an agricultural model based upon deforestation, intensive management and short lasting use of land without the minimal conservation criteria. Similarly, this type of agriculture has not only been creating a big impact at a local level because of deforestation and forest degradation, but it can also get to cause a negative impact at a regional level, such as bioclimatic pattern alterations and hydrographic basin degradation, even at a global level within the carbon cycle itself (Laurence et al 2001).
Nonetheless, up to now, little has been discussed or analyzed regarding the potential role of Agroforestry in such different scenarios of land use in the Amazon, so Agroforestry is considered as a contributing alternative that could eventually reduce the pressure exert by deforestation of new areas with agriculture purposes, through the rehabilitation of degraded forest areas, enhancing previously established productive fallow land portions, and facilitating a passive restoration during the successive natural regeneration of the secondary forest. This would be a simultaneous contribution to the conservation and recovery of the biodiversity and the carbon sinks, meaning a further production of goods and services that would help creating better quality of life conditions for the locals.
Shifting cultivation, or slash-burn practices have been ancestrally performed by many ethnic groups in the Amazon basin, and it has consisted in the deforestation of small areas of primary and secondary forests (