History of Natural Resource Use and Environmental Impacts in an Interfluvial Upland Forest Area in Western Amazonia
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History of natural resource use and environmental impacts in an interfluvial upland forest area in western Amazonia ANDERS SIREN Siren, Anders (2014). History of natural resource use and environmental impacts in an interfluvial upland forest area in western Amazonia. Fennia 192: 1, pp. 36–53. ISSN 1798-5617. Much of the research done on environmental impacts by Amazonian indigenous peoples in the past focus on certain areas where archaeological remains are particularly abundant, such as the Amazon River estuary, the seasonally inun- dated floodplain of the lower Amazon, and various sites in the forest-savannah mosaic of the southern Amazon. The environmental history of interfluvial up- land areas has received less attention. This study reconstructed the history of human use of natural resources in an upland area of 1400 km2 surrounding the indigenous Kichwa community of Sarayaku in the Ecuadorian Amazon, based on oral history elicited from local elders as well as historical source documents and some modern scientific studies. Although data is scarce, one can conclude that the impacts of humans on the environment have varied in time and space in quite intricate ways. Hunting has affected, and continues affecting, basically the whole study area, but it is now more concentrated in space than what it has probably ever been before. Also forest clearing has become more concentrated in space but, in addition, it has gone from affecting only hilltops forests to affect- ing alluvial plains as well as hilltops and, lately, also the slopes of the hills. Keywords: Amazonia; Ecuador; Environmental history; Forest clearing; Hunting; Indigenous peoples Anders Siren, Division of Geography, P.O. Box 64, FI-00014 University of Hel- sinki. E-mail: [email protected] Introduction as forests with elevated concentrations of useful tree species, earth works, and anthropogenic To what extent the Amazonian forests are ‘wilder- black-earth deposits. Such evidence led some au- ness’, and what legacies past generations of indig- thors to make quite radical conclusions, claiming enous peoples have left on the forest ecosystem, that the Amazonian forests were ‘anthropogenic’ are questions that have been intriguing researchers (Gómez-Pompa & Kaus 1992) and that the idea of over the last few decades. Amazonian forests were the forests of Amazonia being pristine was nothing long thought a pristine wilderness, but since the but a ‘myth’ (Denevan 1992, 2011). late 1980’s a series of studies using a wide variety Other authors, however, argue that although of approaches, including studies of historical there is evidence of heavy pre-Columbian human source documents and archaeological artefacts, as influence on the environment at certain sites, well as biological methods based on dendrochro- these sites are not representative of Amazonia as nology and paleobotany, and even remote sens- a whole. Such authors call for a more considered ing, have challenged this view (e.g. Balée 1989, assessment of the spatial distribution of the eco- 1992; Denevan 1992; Gómez-Pompa & Kaus logical impacts of pre-Columbian peoples, and 1992; Bush & Colinvaux 1994; Cleary 2001; Pärss- argue that most of Amazonia was sparsely popu- inen et al. 2009; Levis et al. 2012). Such studies lated and subject to relatively minor environmen- have shown that forests that previously were tal impacts, as forest clearing and dispersal of thought to be pristine, in reality have been subject useful plants affected only very limited areas, to disturbance and modifications by humans dur- whereas the rest was subject only to the much ing thousands of years, leaving behind traces such milder impacts of hunting and gathering (Bush & URN:NBN:fi:tsv-oa8825 DOI: 10.11143/8825 FENNIA 192: 1 (2014) History of natural resource use and environmental impacts... 37 Silman 2007; Barlow et al. 2012; McMichael et is an issue that has been intensively debated, it al. 2012a, 2012b). Even though hunting and gath- should not be forgotten that it is also highly rel- ering obviously have much milder impacts than evant to study such impacts − or the absence the outright removal of the entire forest cover, one thereof − after the arrival of Europeans to the should, however, be careful not to underestimate continent. Writings on environmental history of their potential ecological impacts. In many differ- Amazonia since the 16th century tend, however, ent ecosystems around the world, it has been to focus narrowly on the impacts caused by non- shown that even harvest of just one or a few spe- indigenous settlers and ‘western’ society, partic- cies may have cascade effects on entire ecosys- ularly on areas subject to large-scale deforesta- tems, and may have so even if harvest levels are tion (e.g. Sponsel 1992), thus missing what has relatively modest (Redford & Feinsinger 2001; been going on in rest of Amazonia, where the Milner-Gulland 2008; Salo et al. 2014: 225−241). environment has been subject to more subtle im- In tropical forests, a multitude of species are pacts, or even been recovering from previous im- hunted, and many of them perform important pacts. functions as herbivores, seed predators and seed Much of the research done on environmental dispersers. Experimental studies and case studies impacts by Amazonian and Neotropical indige- in small areas indicate that hunting in tropical for- nous peoples in the past focus on pre-Columbian ests may harm recruitment of trees whose seeds times and on certain areas where archaeological are dispersed by large animals, and instead favor remains are particularly abundant, such as the lianas and such trees whose seeds are dispersed Yucatán (Foster & Turner 2004), the Amazon Riv- by bats and wind (Stoner et al 2007; Wright et al. er estuary (e.g. Roosevelt 1999), the seasonally 2007; Terborgh et al. 2008). Although such stud- inundated floodplain of the lower Amazon (e.g. ies often discuss the potential impacts current Denevan 1996), and various sites in the forest- hunting may have on the future structure and savannah mosaic of the southern Amazon (e.g. composition of the forest, they much less often Balée 1989, 1992; Mayle et al. 2007). The envi- discuss the legacies that potentially may have al- ronmental history of interfluvial upland areas, ready been left on the forest by millennia of hunt- near the Andes Mountains, has received less at- ing by humans in the past. An exception is Schüle tention. This research focuses on such an inter- (1992a, 1992b) who suggested that the closed fluvial upland area in western Amazonia, and forests of Amazonia as we know them today actu- primarily on post-Columbian times up to the turn ally may be a result of Pleistocene overhunting of the millennium. The objective is to recon- that exterminated giant sloths and other megafau- struct, to the extent possible given the availabili- nal elements whose feeding kept the landscape ty of data, the character, intensity, and spatial relatively open. In spite of the potentially very im- distribution of human impacts on the environ- portant implications of this idea, these works ment during the last five centuries. have been relatively rarely cited − not even to put This study responds, in two ways, to a call forward counterarguments − and have had little made for more attention to the spatial distribu- impact on conservation science and practice in tion of the ecological impacts of indigenous peo- neotropical rainforests. ples (cf. Bush & Silman 2007; Barlow et al. 2012; The intensity of hunting is typically highly var- McMichael et al. 2012a, 2012b). First, the study iable in space (Peres & Lake 2003; Sirén et al. area lies in a type of natural environment that has 2004), implying that areas near human settle- seldom been subject to this kind of study, and, ments, roads, and navigable rivers, are currently second, the study itself has an explicitly spatial subject to very intense impacts, whereas areas at approach, focusing on how environmental im- a distance of above some 9−15 km from settle- pacts have been distributed in space within the ments and transport routes are almost unaffected study area. By providing historical depth as well by hunting. Any ecological legacies of hunting, as a view of the spatial variability of resource use in the form of changed species composition or in the particular area studied, this paper contrib- structure of the forest, must, in the same manner, utes to the ongoing quest for better understand- largely depend on the spatial patterns of hunting ing past interactions between humans and nature in the past, but this has rarely been examined. in Amazonia, including how human activities Although the environmental impact caused by may have left lasting – although not always read- indigenous Amazonians in pre-Columbian times ily visible − traces on the forest composition. 38 Anders Siren FENNIA 192: 1 (2014) Study area: The lands of the Sarayaku Sarayaku lands. The surrounding alluvial plains community occasionally get flooded for a day or two after heavy rains, but there is no seasonal flooding, so the forests on these plains are very distinct from Sarayaku is a community located along the middle the seasonally floodedvarzea forests of lower Am- stretches of the Bobonaza river, in the Pastaza azonia. Annual rainfall is about 3000−3500 mm, province, in Ecuadorian Amazonia (Fig. 1). The and the elevation in the area is 330−640 m a. s. l. nearest road is about 30 km upriver. The landscape Natural environmental variability in the area has consists of old fluvial deposits that have been up- been discussed by Sirén et al. (2013). lifted by the eastward movement of the Andes and A catholic mission was established at the site heavily dissected by erosion (Räsänen et al. 1990). around 1830 (Jerves 1930; Espinosa 1943b) or Thus, the topography is rugged and characterized possibly already in 1817 (Reeve 1988: 67).