Alaska Pacific University

About: Alaska Pacific University is a education organization based out in Anchorage, Alaska, United States. It is known for research contribution in the topics: Population & Glacier. The organization has 158 authors who have published 264 publications receiving 4862 citations. The organization is also known as: Alaska Methodist University.

Defining Ecological Drought for the Twenty-First Century

Abstract: DECEMBER 2017 AMERICAN METEOROLOGICAL SOCIETY | THE RISING RISK OF DROUGHT. Droughts of the twenty-first century are characterized by hotter temperatures, longer duration, and greater spatial extent, and are increasingly exacerbated by human demands for water. This situation increases the vulnerability of ecosystems to drought, including a rise in drought-driven tree mortality globally (Allen et al. 2015) and anticipated ecosystem transformations from one state to another—for example, forest to a shrubland (Jiang et al. 2013). When a drought drives changes within ecosystems, there can be a ripple effect through human communities that depend on those ecosystems for critical goods and services (Millar and Stephenson 2015). For example, the “Millennium Drought” (2002–10) in Australia caused unanticipated losses to key services provided by hydrological ecosystems in the Murray–Darling basin—including air quality regulation, waste treatment, erosion prevention, and recreation. The costs of these losses exceeded AUD $800 million, as resources were spent to replace these services and adapt to new drought-impacted ecosystems (Banerjee et al. 2013). Despite the high costs to both nature and people, current drought research, management, and policy perspectives often fail to evaluate how drought affects ecosystems and the “natural capital” they provide to human communities. Integrating these human and natural dimensions of drought is an essential step toward addressing the rising risk of drought in the twenty-first century. Part of the problem is that existing drought definitions describing meteorological drought impacts (agricultural, hydrological, and socioeconomic) view drought through a human-centric lens and do not fully address the ecological dimensions of drought.

Theory of marine communities: the intermediate disturbance hypothesis

Abstract: The theoretical validity of the intermediate disturbance hypothesis is investigated with a model for hierarchical competition between marine species that have space-limited, benthic adults and pelagic larvae. The model explicitly incorporates larval and adult dynamics for two species, one of which overgrows the other. Conclusions include: (1) The subordinate must be a stress tolerator or ruderal for coexistence with a competitive dominant. (2) The intermediate disturbance principle is a moderate-to-high settlement phenomenon: coexistence is possible at sufficiently low settlement even without the aid of disturbance, but at high settlement, a dominant with greater benthic ability excludes the subordinate at all levels of disturbance. (3) Given coexistence, increasing disturbance drives the dominant extinct first. (4) For a fixed level of disturbance, an “intermediate recruitment hypothesis” holds: at low settlement only the subordinate exists, at intermediate settlement there is coexistence, and at high se...