Treesearch

Sweetclover (Melilotus alba) is a nonnative legume that has formed dense and extensive patches along several rivers in Alaska. Our research objective was to determine if sweetclover impacts recruitment of native seedlings in floodplain habitats. To determine if sweetclover impacted recruitment, we conducted a removal experiment along two rivers in interior Alaska. When compared to areas where sweetclover was removed, areas with sweetclover had approximately 50% greater mortality of native seedlings, 25% less recruiting species, and a significant reduction in the quantity of light available...

To identify suitable methods for reforestation, we evaluated the interacting effects of past disturbance, stock types, and site preparation treatments on white spruce (Picea glauca (Moench) Voss) seedling survival and growth across a range of sites in Alaska. Replicated experiments were established in five regions. At each site, two complete installations differed in time since disturbance: "new" units were harvested immediately before spring planting and "old" units were harvested at least 3 years before planting. We compared mechanical scarification before planting, broadcast herbicide...

One of the greater challenges in conserving fungi comes from our incomplete knowledge of degree of rarity, risk status, and habitat requirements of most fungal species. We discuss approaches to immediately begin closing knowledge gaps, including: (1) harnessing collective expert knowledge so that data from professional experiences (e.g., personal collection and herbarium records) are better organized and made available to the broader mycological community; (2) thinking outside the mycology box by learning and borrowing from conservation approaches to other taxonomic groups; (3) developing...

Demographic structure is central to understanding the dynamics of animal populations. However, determining the age of free-ranging mammals is difficult, and currently impossible when sampling with noninvasive, genetic-based approaches. We present a method to estimate age class by combining measures of telomere lengths with other biologically meaningful covariates in a Bayesian network. We applied this approach to American and Pacific martens (Martes americana and M. caurina) and compared predicted age with that obtained from counts of cementum annuli. Using telomere length and the covariate...

Altered global climates in the 21st century pose serious threats for biological systems and practical actions are needed to mount a response for species at risk. We identify management actions from across the world and from diverse disciplines that are applicable to minimizing loss of amphibian biodiversity under climate change. Actions were grouped under three thematic areas of intervention: (i) installation of microclimate and microhabitat refuges; (ii) enhancement and restoration of breeding sites; and (iii) manipulation of hydro period or water levels at breeding sites. There are...

Conservation of genetic diversity is important for continued evolution of populations to new environments, as well as continued availability of traits of interest in genetic improvement programs. Rapidly changing climates present new threats to the conservation of forest genetic resources. We can no longer assume that in situ reserves will continue to preserve existing genetic diversity. Management of reserves should become more active. In some reserves, existing genetic diversity should be preserved by creating stands that are more resistant to threats using silvicultural treatments such...

Extensive and rapid losses of sea ice in the Arctic have raised conservation concerns for the Pacific walrus (Odobenus rosmarus divergens), a large pinniped inhabiting arctic and subarctic continental shelf waters of the Chukchi and Bering seas. We developed a Bayesian network model to integrate potential effects of changing environmental conditions and anthropogenic stressors on the future status of the Pacific walrus population at four periods through the twenty-first century. The model framework allowed for inclusion of various sources and levels of knowledge, and representation of...

Western redcedar (Thuja plicata Donn ex D. Don.) is an important North American tree species, but little information is available on its long-term responses to silvicultural treatments. Stand responses (mortality, ingrowth, basal area and volume growth, and distributions of trees by diameter and height classes) were followed for 25 years after thinning and fertilization treatments (alone and in combination) were applied to a naturally regenerated, low site quality western redcedar stand on the Olympic Peninsula in western Washington, USA. Mortality was low overall, but the densest stands...

Our turtle heritage is diminishing at a rate outpacing that of other main animal groups. The 2011-Year of the Turtle partnership and campaign is an opportunity to raise awareness for turtles, celebrate our turtle heritage, herald conservation and research successes, and identify gaps in our understanding that can be the focus of future work. We outline seven conservation and research implications of the current turtle crisis, and associated conservation opportunities and actions. If we, the turtle conservation community can accomplish efforts in these selected areas, we can greatly help to...

Following the decades-long warming and drying trend in Alaska, there is mounting evidence that temperature-induced drought stress is associated with disease outbreaks in the boreal forest. Recent evidence of this trend is an outbreak of Cytospora canker disease (fungal pathogen Valsa melanodiscus [anamorph = Cytospora umbrina]) on Alnus species. For Alnus fruticosa, we examined the effects of water stress on disease predisposition, and the effects of disease and water stress on host physiology. In two trials, we conducted a full-factorial experiment that crossed two levels of water stress...