Applying Ecological Knowledge to Landuse Decisions
edited by Holm Tiessen and John W. B. Stewart.

ISBN 978-85-99875-04-9

A synthesis of IAI Collaborative Research Networks conducted by the Inter-American Institute for Global Change Research with SCOPE, the Scientific Committee on Problems of the Environment, and IICA, the Inter-American Institute for Cooperation on Agriculture

159 pages, available for download.

The IAI has just concluded a synthesis PDF of several of its collaborative research networks on terrestrial ecosystems, forests, grasslands, agriculture and river margins that explored how environmental science may be used to guide landuse decisions. The networks' investigators contributed results and thoughtful analysis that go beyond scientific papers to provide a transdisciplinary vision of the issues and opportunities in planning landuse for the future.

The synthesis shows that ecological knowledge is used to influence landuse decisions in two different ways. Knowledge of ecosystem function and ecosystem services is used to argue for ecosystems conservation and to chose protected areas. On the other hand, knowledge of ecosystem process can be applied to land management to develop more resilient, lower input, production systems that use some of the efficiencies which natural selection and adaptation has
produced in natural ecosystems. For example, knowing that wetlands provide flood protection and that riparian strips help maintain water quality, preservation of such areas is advocated to maintain these ecosystem services. Knowledge of nutrient cycling mechanisms in natural vegetation can be applied to resource management to emulate these processes, for instance by enhancing nutrient cycling through agroforestry or managing crop residues to provide nutrient release synchronous to crop demands.

There is a wealth of information on the consequences of impairing vital ecosystem services as a result of landuse change. These include reduced soil water infiltration rates resulting in floods and erosion, soil organic matter and nutrient loss resulting in reduced fertility and carbon stocks, and loss of vegetation cover which changes evapo-transpiration and local to regional climate regulation. These processes on land affect water resources through contamination, increased sediment transport and siltation, increased amplitudes of river flow, floods and water shortages. Under the predicted effects of climate change of drier and longer droughts and more intense rains such impaired ecosystems will be much more vulnerable still.

Ecosystem services are used to different degrees by different sections of society. Reduced access to forest products (timber, fuel wood, medicines and honey) as a result of landuse change to agriculture may affect other social groups than those benefiting directly from the agricultural use. Alterations in functional biodiversity therefore lead to differential benefits and vulnerabilities for different stakeholders, both locally and remotely. This is an important emerging issue requiring both a scientific analysis of resource use in its social context and a policy dialogue.

In all production systems, ecosystem functions and services are partly substituted by management interventions, energy and material inputs, such as irrigation, nutrient additions, pesticide or herbicide applications, or landscape alterations such as terracing. Agriculture or forestry production pays for the needed substitutions. The costs can be reduced by maintaining or restoring some ecosystem services. Agroforestry systems for instance can restore nutrient cycling and carbon sequestration lost with the clearing of forests. Agroforestry, crop rotations, mixed cropping and green manuring can also restore biodiversity in an agricultural landscape.

Value judgments, often link small-holder production systems that are not integrated into the agro-industrial chain, and follow subsistence objectives with minimum external inputs to an idea of being "agro-ecological". Such a link between ecosystem preservation and poverty highlights the tension between ecological conservation and societal aspirations. Restitution of ecosystem services to managed landscapes is a scientific and societal challenge. This important new IAI publication will undoubtedly contribute to the needed knowledge and emerging discussions.