Bruce C. Forbes, Nancy Fresco, Anatoly Shvidenko, Kjell Danell and F. Stuart Chapin, Ill Geographic Variations in Anthropogenic Drivers that Influence the Vulnerability and Resilience of Social-Ecological systems Across the circumpolar North large disparities in the dis- tribution of renewable and nonrenewable resources, hu- man population density, capital investments, and basic residential and transportation infrastructure combine to create recognizable hotspots of recent and foreseeable change. Northern Fennoscandia exemplifies a relatively benign situation due to its current economic and political stability. Northern Russia is experiencing rapid, mostly negative changes reflecting the general state of crisis since the collapse of the Soviet Union. North America enjoys a relatively stabie regulatory structure to mitigale environmental degradation associated wilh industry, but is on the verge of approving massive new development schemes that would significantly expand lhe spatial ex- ten1 of potentially affected social-ecological systems. In- stitutional or regulatory context influences the extent to which ecosystem services are buffered against environ- mental change. Wilh or without a warming climate, cer- tain geographic areas appear especially vulnerable to damages that may lhreaten their ability to supply goods and services in the near future. Climate change may exacerbate this situation in some places but may of- fer opportunities to enhance resilience in the long term. INTRODUCTION Evolving over long per~ods during thc Tertiary and Quaternary (I ), elements of the boreal and arctic tundra biota have adapted to high variability in climate and other variables, such as her- bivory (2). Resilience is expressed at several levels from the individual to the ecosystem (3). Even when entire biomes have disappeared, as in the case of the steppe-tundra of Beringia (2), isolated relics or fragmentary analogues of ancient communi- ties have persisted, albeit in impoverished forms, indicating that some inter-species relationships are resilient in the face of ma- jor, long-term environmental change (4). The range of adaptation among human cultures during the Holocene is similarly impressive. During this period the whal- ing and reindeer-dependent cultures of Eurasia were undergo- ing profound changes, partly in response to climate (5). More recently, contemporary cultures of the taiga and tundra zones have experienced intensive outside economic and institutional pressures (6, 7), as well as relatively short-term but significant climate change 111 some regions (8, 9). Overall, northern indig- enous peoples are experts in adapting to shifting conditions (en- vironmental, social, economic) and recognize their own abilities in this regard (7). Despite this record of resilience and the capac~ty to buffer against change, northern ecosystems have traditionally held a reputation for being 'fragile' and therefore vulnerable to im- mediate, long lasting and perhaps irreversible change. The flip Arnb~o VoI 33 No 6 Augus12004 r Royal Sssdlsh Acsdt hrtp /,uws ar s~de of fragility is ostensibly stability. Yetto some early observ- ers, arctic ecosystems appeared to be so thoroughly affected by the natural disturbance regimes associated with frozen ground that 'stabil~ty', as represented by so-called 'climax communi- ties', was simply absent (10). More recent thinking incorpo- rates the disturbance regimes into the theoretical framework of community processes that direct succession and the indi- vidualistic responses of specles. In this framework, transitions between states are caused by the different disturbance events, and alternative stable states are possible (I I). It is only in the last 35 years or so that concern has been ex- pressed about the ab~lity for humans to h a w significant impacts on northern ecosystems (I 2). From the 1970s onwards, anthro- pogenic drivers have come to be recognized as increasingly critical. Some of the same drivers first identified are still impor- tant, in addition to more recently acknowledged threats, such as persistent organic pollutants (POPS) and tour~sm (13). Other key drivers include changes in fire and ungulate grazing regimes (14-15). Monitoring efforts can be somewhat patchy spatially and temporally, but there is little doubt that the extent of human alteration to arctic and boreal social-ecosyslems is growing (1 6), in part because some of the potential for impacts to accumulate in space and time (17). These cumulative impacts may occur independently of each other, or may be exacerbated through in- teractions among drivers of change. As with the recently detected and anticipated climate change (18), the scale and intensity of anthropogenic drivers varies geo- graphically. Certain areas appear especially vulnerable to dam- ages that may threaten their ability to supply goods and services in the near future. In this paper we present an overview of these variations and a discussion of their implications for pol~cy. GEOGRAPHIC VARIATION IN DRIVERS Alaska In Alaska, a strong regulatory framework coupled with a relative lack of widespread ecosystem degradation compared to temper- ate regions provides a generally positive outlook for the future maintenance of ecosystem integrity. The state's total area is 656 424 mi2 (1 056 186 km2). The population of nearly 650 000 in- cludes some 120 000AlaskaNatives. Much of the land is public- ly owned, including an extensive network of land under various levels of state and national protection. Nevertheless, population growth, urban expansion, and ever-increasing market demands place pressures on ecosystem resources. The result may be some degree of ecosystem degradation, due to creation of habitat-frag- menting transportation corridors; immediate and long-term im- pacts of mining and drilling here and in northwestern Canada; and alteration of natural fire regimes. Alaska's resources are also directly and ind~rectly threatened by climate change. ?my ofSc%cnccs 2001 nbio kva.se 377