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Although climate change is predicted to place mountain-top and other narrowly endemic species at severe risk of extinction, the ecological processes involved in such extinctions are still poorly resolved. In addition, much of this biodiversity loss will likely go unobserved, and therefore largely unappreciated. The Haleakalā silversword is restricted to a single volcano summit in Hawai'i, but is a highly charismatic giant rosette plant that is viewed by 1-2 million visitors annually. We link detailed local climate data to a lengthy demographic record, and combine both with a population-wide assessment of recent plant mortality and recruitment, to show that after decades of strong recovery following successful management, this iconic species has entered a period of substantial climate-associated decline. Mortality has been highest at the lower end of the distributional range, where most silverswords occur, and the strong association of annual population growth rates with patterns of precipitation suggests an increasing frequency of lethal water stress. Local climate data confirm trends toward warmer and drier conditions on the mountain, and signify a bleak outlook for silverswords if these trends continue. The silversword example foreshadows trouble for diversity in other biological hotspots, and illustrates how even well-protected and relatively abundant species may succumb to climate-induced stresses., (© 2012 Blackwell Publishing Ltd.)

Mountains are one of few ecosystems little affected by plant invasions. However, the threat of invasion is likely to increase because of climate change, greater anthropogenic land use, and continuing novel introductions. Preventive management, therefore, will be crucial but can be difficult to promote when more pressing problems are unresolved and predictions are uncertain. In this essay, we use management case studies from 7 mountain regions to identify common lessons for effective preventive action. The degree of plant invasion in mountains was variable in the 7 regions as was the response to invasion, which ranged from lack of awareness by land managers of the potential impact in Chile and Kashmir to well-organized programs of prevention and containment in the United States (Hawaii and the Pacific Northwest), including prevention at low altitude. In Australia, awareness of the threat grew only after disruptive invasions. In South Africa, the economic benefits of removing alien plants are well recognized and funded in the form of employment programs. In the European Alps, there is little need for active management because no invasive species pose an immediate threat. From these case studies, we identify lessons for management of plant invasions in mountain ecosystems: (i) prevention is especially important in mountains because of their rugged terrain, where invasions can quickly become unmanageable; (ii) networks at local to global levels can assist with awareness raising and better prioritization of management actions; (iii) the economic importance of management should be identified and articulated; (iv) public acceptance of management programs will make them more effective; and (v) climate change needs to be considered. We suggest that comparisons of local case studies, such as those we have presented, have a pivotal place in the proactive solution of global change issues. [ABSTRACT FROM AUTHOR]

Discusses the sensitivity of island tropical montane cloud ecosystems to global climate change. Variability and precipitation of hurricane incidence; Vulnerability of island biota to biological invasions; Prospects for the conservation of endemic biota and vegetation.