BALANCING HUMAN NEEDS & ECOSYSTEM FUNCTION

Nissa Sharfina Nayla(25)

X OTKP 2

BALANCING HUMAN NEEDS & ECOSYSTEM FUNCTION

REVIEWS 249 Land-use choices: balancing human needs and ecosystem function Ruth S DeFries", Jonathan A Foley', and Gregory P Asner** Conversion of land to grow crops, raise animals, obtain timber, and build cities is one of the foundations of human civilization. While land use provides these essential ecosystem goods, it alters a range of other ecosystem functions, such as the provisioning of freshwater, regulation of climate and biogeochemical cycles, and maintenance of soil fertility. It also alters habitat for biological diversity. Balancing the inher- ent trade-offs between satisfying immediate human needs and maintaining other ecosystem functions requires quantitative knowledge about ecosystem responses to land use. These responses vary according to the type of land-use change and the ecological setting, and have local, short-term as well as global, long- term effects. Land-use decisions ultimately weigh the need to satisfy human demands and the unintended ecosystem responses based on societal values, but ecological knowledge can provide a basis for assessing the trade-offs. Front Ecol Environ 2004; 2(5): 249-257 Land-use change is intricately related to both economic and other ecosystem goods. This basic aspect of human development and the ecological characteristics of the land- scape. Within a particular region, land use potentially fol- food to feed his family from marginal lands in southem lows a series of transitions that parallel economic develop- ment - from wildlands with low human popul subsistence agriculture with the majority of the population employed in food pro- to appropriate primary production for human consumption duction for local consumption, to intensive agriculture sup- porting mainly urban populations (Figure 1; Mustard et al. in the watershed, atmosphere, human health, and biological press). Regions might pass through these transitions rapidly over a period of years, or slowly over a period of centuries. In some cases, a particular region may never complete the full transition if economic conditions do not enable the infra- structure for fertilizer, irrigation, or transport; if consumer demand for products from intensive agriculture is too weak; Dcople transform landscapes to obtain food, fiber, timber, existence holds true whether a subsistence farmer is growing a multinational Africa irrigating land in the midwestern US to export crops world- wide. The intended consequence of this land use is clear - is fertilizing and densities, frontier clearing (Vitousek et al. 1986). The unintended consequences for diversity often remain hidden. The implicit assumption is that the intended consequence of appropriating primary production for human consumption outweighs the unin- tended consequences for other ecosystem functions. In a nutshell: or if arable and accessible land is not available. We can see examples of different land-use transitions occurring throughout the world. Parts of the Amazon basin, for example, are currently experiencing a rapid tran- sition from wildlands to intensive agriculture within a period of years, as forests that were initially cleared for pas- ture are now being converted to intensive agriculture areas where infrastructure and ecological conditions are conducive to this type of usage (Laurance et al. 2001). Other regions, such as the Indian subcontinent and China, experienced frontier clearing many thousands of years ago, and much of the agricultural activity is still for local subsis- tence (Ellis and Wang 1997), except in pockets such as the MD (rdefries@geog umd edu): "Earth System Science Interdisciplinary Punjab where fertile soils and infrastructure inputs result- ing from the Green Revolution have completed the transi- tion. Other parts of the world remain in the subsistence for Environmental Studies, University of Wisconsin-Madison, stage, with few near-term prospects for moving through the transition to intensive agriculture. In sub-Saharan Africa, Stumford University, Stanford, CA: 

'Departmenit of Geological and for instance, the vast majority of the population obtains • Land-use change to provide food, fiber, timber, and space for settlements is one of the foundations of human civilization

 • There are often unintersded consequences, including feedbacks to climate, altered flows of freshwater, changes in disease vec- rors, and reductions in biodiversity

 • Land-use decisions ultimately weigh the inherent trade-offs between satisfying immediate human needs and unintended ecosystem consequences, based on societal values 

• Ecological knowledge to assess these ecosystem consequences is a prerequisite to assessing the full range of trade-offs involved in land-use decisicins 'Deparement of Geography, University of Maryland, College Park, Center, Universiry of Maryland, Colege Park, MD; Center for Sustainability and the Global Envaronment, Gaylord Nelson Institute Madison, WI; "Department of Global Ecokogy, Camegie Institution, Environmental Sciences, Stanford University, Stanford, CA food from subsistence farming or pastoralism. 

thanksʕ•ᴥ•ʔ