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Widespread glacial retreat is now occurring in many arctic mountain ranges, yet little is known about primary succession following deglaciation in these settings. Newly created habitats could provide refugia for flora and fauna whose ranges are threatened elsewhere by rapid warming. To assess vegetation responses to glacial retreat in an arctic–alpine setting, we first describe plant community development on two recently deglaciated moraines in the Brooks Range. We then compare these recent communities with communities developed along a moraine chronosequence that spans >125,000 years and ranges in altitude between 800 and 1,700 m.a.s.l. Results show that (1) within twenty-two to thirty-six years following deglaciation, primary succession begins with the assembly of small communities of eight to thirteen vascular and nonvascular plant species; (2) species turnover is low, with many pioneer taxa, particularly lichens, persisting at the oldest sites and across all altitudes; and (3) overall, succession is directional and slow, with species richness increasing for up to 25,000 years, and percentage vegetation cover reaching >100 percent on the oldest glacial deposits. This is the first vegetation study on primary succession in the high central Brooks Range, and it supplies a previously missing alpine element within a vegetation transect across northern Alaska's bioclimatic gradient. [ABSTRACT FROM AUTHOR]

Subsistence harvesting and wild food production by Athabascan peoples is part of an integrated social--ecological system of interior Alaska. We describe effects of recent trends and future climate change projections on the boreal ecosystem of interior Alaska and relate changes in ecosystem services to Athabascan subsistence. We focus primarily on moose, a keystone terrestrial subsistence resource of villages in that region. Although recent climate change has affected the boreal forest, moose, and Athabascan moose harvesting, a high dependence by village households on moose persists. An historical account of 20th century socioeconomic changes demonstrates that the vulnerability of Athabascan subsistence systems to climatic change has in some respects increased while at the same time has improved aspects of village resilience. In the face of future climate and socioeconomic changes, communities have limited but potentially effective mitigation and adaptation opportunities. The extent to which residents can realize those opportunities depends on the responsiveness of formal and informal institutions to local needs. For example, increases in Alaska's urban population coupled with climate-induced habitat shifts may increase hunting conflicts in low-moose years. This problem could be mitigated through adaptive co-management strategies that project future moose densities and redirect urban hunters to areas of lower conflict. Resume: La recolte de subsistance et la production de nourriture sauvage par le peuple athapascan fait partie d'un systeme socio-ecologique integre de l'interieur de l'Alaska. Nous decrivons les effets des tendances recentes et des projections de changements climatiques a venir sur l'ecosysteme boreal de l'interieur de l'Alaska et nous relions les changements dans les services de l'ecosysteme a la subsistance des athapascans. Nous mettons principalement l'accent sur l'orignal, une ressource terrestre de subsistance cle des villages de cette region. Bien que les changements climatiques recents aient affecte la foret boreale, l'orignal et la recolte d'orignaux par les athapascans, les menages des villages continuent a dependre fortement de l'orignal. Un compte rendu historique des changements socioeconomiques survenus au [20.sup.e] siecle demontre que la vulnerabilite des systemes de subsistances des athapascans aux changements climatiques a a certains egards augmente alors que des aspects de la resilience des villages se sont ameliores durant la meme periode. Face aux changements climatiques et socioeconomiques a venir, les communautes ont des possibilites d'adaptation et d'attenuation limitees mais potentiellement efficaces. Dans quelle mesure les residants peuvent concretiser ces possibilites depend de la capacite de reaction des institutions formelles et informelles aux besoins locaux. Par exemples, des augmentations de la population urbaine de l'Alaska couplees a des changements d'habitat induits par le climat peuvent augmenter les conflits de chasse les annees durant lesquelles l'orignal est peu abondant. On pourrait attenuer ce probleme par des strategies de cogestion adaptative qui predisent la densite des orignaux et redirigent les chasseurs urbains vers des zones moins conflictuelles. [Traduit par la Redaction], Introduction Indigenous Peoples have occupied interior Alaska for 6000-9000 years (Aigner 1986; Langdon 2004). They include Gwich'in, Denaakk'e, Kuskokwim, Tanana, Han, and other culture groups (referred in this paper as [...]

In the boreal forests of interior Alaska, feedbacks that link forest soils, fire characteristics, and plant traits have supported stable cycles of forest succession for the past 6000 years. This high resilience of forest stands to fire disturbance is supported by two interrelated feedback cycles: (i) interactions among disturbance regime and plant--soil--microbial feedbacks that regulate soil organic layer thickness and the cycling of energy and materials, and (ii) interactions among soil conditions, plant regeneration traits, and plant effects on the environment that maintain stable cycles of forest community composition. Unusual fire events can disrupt these cycles and trigger a regime shift of forest stands from one stability domain to another (e.g., from conifer to deciduous forest dominance). This may lead to abrupt shifts in forest cover in response to changing climate and fire regime, particularly at sites with intermediate levels of moisture availability where stand-scale feedback cycles are only weakly constrained by environmental conditions. However, the loss of resilience in individual stands may foster resilience at the landscape scale, if changes in the landscape configuration of forest cover types feedback to stabilize regional patterns of fire behavior and climate conditions. Resume: Dans la foret boreale de l'interieur de l'Alaska, les retroactions qui relient les sols forestiers, les caracteristiques des incendies et celles de la vegetation ont assure le maintien des cycles de succession forestiere pendant les 6000 dernieres annees. Cette grande resilience des peuplements forestiers face aux perturbations causees par le feu est le resultat de deux cycles interrelies de retroactions: (i) les interactions entre le regime de perturbations et les retroactions entre les plantes, le sol et les microbes qui controlent l'epaisseur de l'horizon organique du sol et le recyclage de l'energie et des materiaux et (ii) les interactions entre les conditions du sol, les caracteristiques de la regeneration des plantes et les effets des plantes sur l'environnement qui maintiennent la stabilite des cycles de composition des communautes forestieres. Les incendies inhabituels peuvent perturber ces cycles et declencher un changement de regime des peuplements forestiers d'un domaine de stabilite a un autre (p. ex., d'une foret dominee par des coniferes a une foret dominee par des feuillus). Cela peut entrainer des changements abrupts dans le couvert forestier en reponse aux changements climatiques et a la modification du regime de feux, particulierement dans les stations avec un niveau intermediaire de disponibilite en eau ou les cycles de retroaction a l'echelle du peuplement sont assujettis seulement faiblement aux conditions environnementales. Cependant, la perte de resilience de peuplements particuliers peut favoriser la resilience a l'echelle du paysage si les changements dans la configuration des types de couvert forestier a l'echelle du paysage ont un effet de retroaction qui stabilise les patrons regionaux du comportement du feu et des conditions climatiques. [Traduit par la Redaction], Introduction Earth is undergoing pronounced environmental changes that are strongly influenced by human activities. Climate warming in recent decades is particularly pronounced at high latitudes, and past carbon emissions from [...]

Recent global environmental and social changes have created a set of 'wicked problems' for which there are no optimal solutions. In this article, we illustrate the wicked nature of such [...]

We synthesize our findings of studies in Glacier Bay National Park and Preserve, southeastern Alaska, to elucidate interactions and linkages among terrestrial, lake, stream, and marine intertidal ecosystems as the [...]

Author(s): Michelle C. Mack (corresponding author) [1, 4]; Edward A. G. Schuur [1, 4]; M. Syndonia Bret-Harte [2]; Gaius R. Shaver [3]; F. Stuart Chapin, III [2] Global warming is [...]

In a growing body of literature from a variety of ecosystems is strong evidence that various components of biodiversity have significant impacts on ecosystem functioning. However, much of this evidence [...]

Author(s): F. Stuart Chapin, III [1]; Roger W. Ruess [1] Photosynthesis by terrestrial vegetation accounts for about half of the carbon that annually cycles between Earth and the atmosphere [1]. [...]

Author(s): F. Stuart Chapin III (corresponding author) [1]; Erika S. Zavaleta [2]; Valerie T. Eviner [4]; Rosamond L. Naylor [3]; Peter M. Vitousek [2]; Heather L. Reynolds [5]; David U. [...]