Human Influence on Tropical Forests

A walk on Barro Colorado Island (BCI) is a discovery of an amazing nature, a great many experiments, but also of an environment that has been “isolated” following the construction of the Canal of Panama (1903-1914). Especially from 1923, when it was declared a biological reserve, BCI’s environment benefited from an extraordinary protection from human development and management. Its insular characteristic, as well as its status as a protected environment, made me realize that the BCI forest is probably way different from other forests that we might see later on in this course.

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View from Barro Colorado Island (© Andréanne Lavoie)

As it is said by a lot of scientists, tropical forests have been shaped by humans for centuries (Williams, 2002). Whereas it is not easy to determine the extent of this management, new research tends to describe a reality that probably lies somewhere between a vision of a pristine environment and a built landscape (Piperno, McMichael, & Bush, 2015). In fact, it is now recognized that the Amazonian forest, for example, was harvested and cultivated by people in the last thousand years (Miller & Nair, 2006). Some even describe it as a major center of crop domestication (Clement et al., 2015). Even if the extent of these utilizations has yet to be fully understood and described, the last hundred years have seen a considerable amount of vegetation and landscape reconfigurations, driven notably by a few species of interests, such as the Brazil nut (Shepard Jr & Ramirez, 2011) or the cacao (Cassano, Schroth, Faria, Delabie, & Bede, 2009).

Agroforestry systems, especially home gardens, agroforests and shade cover plantations, are known to have been developed by people in tropical forests, especially for alimentation purposes (Miller & Nair 2006). In fact, many non-timber forest products are an important source of food, medicines, materials, income and energy for a lot of indigenous people living in those environments (Chambers & Leach, 1989), and their cultural importance is still not well documented (Cocks, López, & Dold, 2011).

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Agroforestry systems in Brazil (© Andréanne Lavoie)

So, while we were walking in its paths, the BCI forest made me think of the reasons human shape their environment and transform it to suit their needs. It is intriguing to think about the research that could be done to compare an environment as preserved as BCI and another tropical forest in Panama that has probably experienced modifications. What is the difference between the abundance of species? Is the specific richness different in those environments? Are humans a source of pathogens in tropical forests? Do humans impact species mutualisms? It is truly a fantastic opportunity to have the chance to think about those questions during the course. While I do not think that any of those questions could be answered during the next month, I think that only by asking them we may see the forest in a new way.

Source

Cassano, C. R., Schroth, G., Faria, D., Delabie, J. H. C., & Bede, L. (2009). Landscape and farm scale management to enhance biodiversity conservation in the cocoa producing region of southern Bahia, Brazil. Biodiversity and Conservation, 18(3), 577‑603. https://doi.org/10.1007/s10531-008-9526-x

Chambers, R., & Leach, M. (1989). Trees as savings and security for the rural poor. World Development, 17(3), 329‑342. https://doi.org/10.1016/0305-750X(89)90206-4

Clement, C. R., Denevan, W. M., Heckenberger, M. J., Junqueira, A. B., Neves, E. G., Teixeira, W. G., & Woods, W. I. (2015). The domestication of Amazonia before European conquest. Proceedings of the Royal Society B: Biological Sciences, 282(1812), 20150813. https://doi.org/10.1098/rspb.2015.0813

Cocks, M., López, C., & Dold, T. (2011). Cultural Importance of Non-timber Forest Products: Opportunities they Pose for Bio-Cultural Diversity in Dynamic Societies. In S. Shackleton, C. Shackleton, & P. Shanley (Éd.), Non-Timber Forest Products in the Global Context (Vol. 7, p. 107‑128). Heidelberg: Springer-Verlag. https://doi.org/10.1007/978-3-642-17983-9_5

Miller, R. P., & Nair, P. K. R. (2006). Indigenous Agroforestry Systems in Amazonia: From Prehistory to Today. Agroforestry Systems, 66(2), 151‑164. https://doi.org/10.1007/s10457-005-6074-1

Piperno, D. R., McMichael, C., & Bush, M. B. (2015). Amazonia and the Anthropocene: What was the spatial extent and intensity of human landscape modification in the Amazon Basin at the end of prehistory? The Holocene, 25(10), 1588–1597. https://doi.org/10.1177/0959683615588374

Shepard Jr, G. H., & Ramirez, H. (2011). « Made in Brazil »: Human Dispersal of the Brazil Nut (Bertholletia excelsa, Lecythidaceae) in Ancient Amazonia1. Economic Botany, 65(1), 44–65. https://doi.org/10.1007/s12231-011-9151-6

Williams, M. (2002). Deforesting the earth: from prehistory to global crisis. (University of Chicago Press). Chicago, USA.

 

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