Treesearch

We present evidence that climatic change is an ongoing process and that forest tree populations are genetically differentiated for quantitative traits because of adaptation to specific habitats. We discuss in detail indications that the shift of suitable climatic habitat for forest tree species and populations, as a result of rapid climatic change, is likely to cause significant stresses to natural tree populations. Due to the physical limits of natural migration, tree populations will be unable to keep pace with the moving target that their suitable climatic habitat will become. The...

This paper develops an economic analysis of climate change impacts in the global forest sector. It illustrates how potential future climate change impacts can be integrated into a dynamic forestry economics model using data from a global dynamic vegetation model, theMC2model. The results suggest that climate change will cause forest outputs (such as timber) to increase by approximately 30% over the century. Aboveground forest carbon storage also is projected to increase, by approximately 26 Pg C by 2115, as a result of climate change, potentially providing an offset to emissions from other...

In Strangers on Familiar Soil, Edward Dallam Melillo shows how Californians and Chileans each have one foot on their land and the other connecting them through the Pacific Ocean. Melillo reframes our understanding of US history in the west and links the histories and destinies of Chile and California from 1786 to the current day. Contrary to popular belief, Melillo asserts that California was built by more than westward migration during expansionism in the US. It was also built by influences from Chileans or Chilenos whose country was the last stop after coming around the horn of South...

Many species living in deeper lentic ecosystems exhibit daily movements that cycle through the water column, generally referred to as diel vertical migration (DVM). In this study, we applied bioenergetics modelling to evaluate growth as a hypothesis to explain DVM by bull trout (Salvelinus confluentus) in a thermally stratified reservoir (Ross Lake, WA, USA) during the peak of thermal stratification in July and August. Bioenergetics model parameters were derived from observed vertical distributions of temperature, prey and bull trout. Field sampling confirmed that bull trout prey almost...

Environmental regulations often require wildlife surveys prior to habitat disturbance to avoid impacts or as the basis for planning mitigation, yet project-level surveys may not provide the insights needed to guide long-term management. Management of the red tree vole (Arborimus longicaudus) has largely been based on such surveys. As an alternative approach, we evaluated distribution patterns using frequency of red tree vole occurrence and habitat suitability models to guide conservation planning. We developed a suite of models based on subsets of covariates from two previously developed...

Aging infrastructure coupled with growing interest in river restoration has driven a dramatic increase in the practice of dam removal. With this increase, there has been a proliferation of studies that assess the physical and ecological responses of rivers to these removals. As more dams are considered for removal, scientific information from these dam-removal studies will increasingly be called upon to inform decisions about whether, and how best, to bring down dams. This raises a critical question: what is the current state of dam-removal science in the United States? To explore the...

Managers make decisions regarding if and how to remove dams in spite of uncertainty surrounding physical and ecological responses, and stakeholders often raise concerns about certain negative effects, regardless of whether these concerns are warranted at a particular site. We used a dam-removal science database supplemented with other information sources to explore seven frequently raised concerns, herein Common Management Concerns (CMCs). We investigate the occurrence of these concerns and the contributing biophysical controls. The CMCs addressed are the following: degree and rate of...

Marine derived nutrients delivered by large runs of returning salmon are thought to subsidize the in situ food resources that support juvenile salmon. In the Pacific Northwest, USA, salmon have declined to <10% of their historical abundance, with subsequent declines of marine derived nutrients once provided by large salmon runs. We explored whether low densities (<0.001 spawners/m2) of naturally spawning Chinook Salmon (Oncorhynchus tshawytscha) can affect ecosystem metabolism. We measured gross primary production (GPP) and ecosystem respiration (ER) continuously before, during, and after...

This is a policy discussion paper aimed at addressing possible alternative approaches for environmental flows (e-Flows) assessment and identification within the context of best strategies for fluvial restoration. We focus on dammed rivers in Mediterranean regions. Fluvial species and their ecological integrity are the result of their evolutionary adaptation to river habitats. Flowing water is the main driver for development and maintenance of these habitats, which is why e-Flows are needed where societal demands are depleting water resources. Fluvial habitats are also shaped by the...

The marbled murrelet (Brachyramphus marmoratus) is a threatened seabird that forages in nearshore marine waters but nests inland, commonly in older coniferous forests. Information on ranging behavior and breeding propensity can be useful for informing management, especially when comparisons can be made between declining or threatened populations and more stable, unthreatened populations. Over 5 years, we measured ranging behavior and breeding propensity of marbled murrelets in Washington, USA where murrelets are considered threatened. Our primary objective was to compare space use and...