Management of human interactions with tropical ecosystems: management of secondary drivers

Introduction

The management of human interactions with tropical savanna and rainforest ecosystems, primarily through the management of secondary drivers of degradation (as discussed above), is a huge topic in itself. A long list of natural resource management issues could be examined including; forestry, grazing, cropping, subsistence farming, weed invasion, game hunting, mining, fires, road building, tourism etc. In the following subsections we will use two central case studies to examine the two most widespread and potentially damaging interactions humans have with these ecosystems, forestry and agriculture.

Sustainable Forest Management

As discussed in the introduction to this course tropical rainforests and savanna ecosystems are being deforested, cleared and degraded at an alarming rate and it is essential that appropriate ways of managing these ecosystems for their products, provision of ecosystem services, and use for alternative activities are developed. At the forefront of forest management today is sustainable forest management (SFM), a sub-set of sustainable development that grew out of the concepts of sustainable forestry and sustainable yield.

The Food and Agriculture Organisation (FAO) defines sustainable forest management as:

• the stewardship and use of forests and forest lands in a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfill, now and in the future, relevant ecological, economic and social functions, at local, national, and global levels, and that does not cause damage to other ecosystems.

Criteria and indicators of sustainable forest management are important policy instruments used to implement progress which may be evaluated and reported on. Criteria define and characterise the essential elements, as well as a set of conditions or processes, by which sustainable forest management may be assessed, while indicators can be measured to reveal the direction of change with respect to each criteria.

Criteria and indicators of sustainable forest management are widely used and there are nine international and regional criteria and indicator initiatives involving more than 150 countries are in use (Castaneda et al. 2001). There is growing international consensus on the key elements of sustainable forest management and seven common thematic areas of SFM have emerged:

1. Extent of forest resources,
2. Biological diversity,
3. Forest health and vitality,
4. Productive functions and forest resources (i.e. ecosystem goods),
5. Protective functions of forest resources (i.e. ecosystem services),
6. Socio-economic functions (including many key ecosystem services), and
7. Legal, policy and institutional framework.

Sustainable forest management is a concrete means of applying an ecosystem approach to forests and forest resources. Together these two concepts aim at promoting conservation and management practices which are environmentally, socially and economically sustainable both now and into the future.

Managing Agricultural Activities

Managing agricultural activities in tropical rainforests and savanna ecosystems is a significant topic in itself. In this unit we are going to focus specifically on two case studies of agriculture in these ecosystems rather than the full range of effects and issues involved in managing agricultural activities in tropical ecosystems.

Agriculture Exploitation & Collapse: Failure to Understand Underlying Ecology

The agricultural endeavours of European settlers in Australia’s North provides a classic example of the consequences of failing to adequately understand the underlying ecology of ecosystems.

Slash-and-Burn & Sustainable Agriculture in Tropical Rainforests

The majority of farmers who live in the Brazilian Amazon are relatively recent settlers who have migrated from more temperate regions. The predominant form of agriculture used by these farmers is slash-and-burn agriculture, which involves the clearing and burning of plots of tropical rainforest to plant annual crops such as corn, rice and beans.

This form of agriculture is inappropriate for use on tropical rainforest soils as it strips the relatively infertile soils of nutrients, rendering the soil useless for agriculture in 3-5 years and often unable to be reinvaded by forest species (Caviglia and Kahn 2001).

Slash-and-burn agriculture is another example of an approach to agriculture that fails to adequately understand and accommodate the underlying ecology of the ecosystem.

Indigenous Amazonians and caboclos (settlers of mixed European and Indian descent who have been in the region for hundreds of years) use swidden agriculture, also known as shifting cultivation. This method of agriculture mimics natural disturbances facilitating sustainable use of the relatively infertile Amazonian soil. Small areas are cut and burned for agriculture, used for a few years and then left fallow. During the fallow the surrounding rainforest can quickly reinvade the disturbed area.

An evolving alternative approach to agriculture in tropical rainforest is the use of sustainable agriculture, which uses production techniques that maintain the nutrient cycle and allow for rapid recovery of cleared land. In this context sustainable agriculture involves the use of agroforestry (intercropping), harvesting of native fruits and nuts, fish harvesting, honey harvesting (Caviglia and Kahn 2001).

Agroforestry, also know as intercropping involves the clearing of small areas of land between trees, thereby maintaining much of the canopy cover, and the production of both annual crops such as corn and beans, as well as the nuts and fruits produced by perennial plants.

(Note this definition of agroforestry is specific to it’s use in tropical rainforest regions, particularly throughout the Amazon. In Australia agroforestry is more commonly used to refer to the incorporation of planted woodlots on agricultural land).

Subsistence Use, Value, & Management of Savannas: The “Miombo Woodlands” of Africa

Miombo woodland is the most common southern hemisphere savanna ecosystem. The resources of these ecosystems are central to the livelihoods of millions of rural and urban dwellers (Campbell et al. 1996).