Treesearch

Migratory species employ a variety of strategies to meet energetic demands of postbreeding molt. As such, at least a few species of western Neotropical migrants are known to undergo short-distance upslope movements to locations where adults molt body and flight feathers (altitudinal molt migration). Given inherent difficulties in measuring subtle movements of birds occurring in western mountains, we believe that altitudinal molt migration may be a common yet poorly documented phenomenon. To examine prevalence of altitudinal molt migration, we used 29 years of bird capture data in a series...

The large mediatic coverage of recent massive wildfires across the world has emphasized the vulnerability of freshwater resources. The extensive hydrogeomorphic effects from a wildfire can impair the ability of watersheds to provide safe drinking water to downstream communities and high-quality water to maintain riverine ecosystem health. Safeguarding water use for human activities and ecosystems is required for sustainable development; however, no global assessment of wildfire impacts on water supply is currently available. Here, we provide the first global evaluation of wildfire risks to...

Stand-replacing fire has profound ecological impacts in conifer forests, yet there is continued uncertainty over how best to describe the scale of stand-replacing effects within individual fires, and how these effects are changing over time. In forests where regeneration following stand-replacing fire depends on seed dispersal from surviving trees, the size and shape of stand-replacing patches are critical metrics that are difficult to describe and often overlooked. We used a novel, recently-developed metric that describes the amount of stand-replacing area within a given distance of a...

On the basis of data from 2000 to 2010, we investigated the separate effects of the uptake of forest certification and the usage of recycled paper on imports of paper and paperboard into Germany and the United States. Using panel data methods and based on a conventional Armington trade model, we find that the effects of two main forest certification schemes—the Programme for Endorsement of Forest Certification (PEFC) and the Forest Stewardship Council (FSC)— differ between markets. In Germany, the PEFC was negatively related to imports. In the United States, imports were preferred from...

Virus–plant interactions range from parasitism to mutualism. Viruses have been shown to increase fecundity of infected plants in comparison with uninfected plants under certain environmental conditions. Increased fecundity of infected plants may benefit both the plant and the virus as seed transmission is one of the main virus transmission pathways, in addition to vector transmission. Trade-offs between vertical (seed) and horizontal (vector) transmission pathways may involve virulence, defined here as decreased fecundity in infected plants. To better understand plant–virus symbiosis...

Summary. Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial production in the United States and other countries, and currently impacts the avocado industry in Florida. As laurel wilt spreads, the National Germplasm Repository for avocado in Miami (USDA-ARS) and commercial and residential production in other states (e.g., California and Hawaii), U.S. protectorates (Puerto Rico), and other countries are at risk. In the United States, value-added production of avocado of more than $1.3 billion/year is...

This report describes and documents the OpCost forest operations cost model, a key component of the BioSum analysis framework. OpCost is available in two editions: as a callable module for use with BioSum, and in a stand-alone edition that can be run directly from R. OpCost model logic and assumptions for this open-source tool are explained, references to the literature used in all of the submodels included in OpCost are provided, and guidance is offered on how to change the default hourly machine rates associated with overall logging cost calculations. OpCost enhancements such as cost...

Movements among leks by breeding birds (i.e., interlek movements) could affect the population's genetic flow, complicate use of lek counts as a population index, and indicate a change in breeding behavior following a disturbance. We used a Bayesian multi-state mark-recapture model to assess the daily probability of male greater sage-grouse (Centrocercus urophasianus) interlek movements and estimate factors influencing movements among leks. We fitted 145 males with solar Argos global positioning systems platform transmitter terminals over 4 years (2011-2014) in Carbon County, Wyoming, USA....

Many common pool resources (CPRs) have tipping points - stock levels below which the resource is permanently damaged or destroyed - but the specific levels at which these thresholds are crossed are rarely known with certainty. We model a CPR in which uncertainty simultaneously creates a Prisoner's Dilemma and a Coordination Game. This model highlights a novel mechanism through which uncertainty incentivizes the overuse of a CPR. In the model, two Nash Equilibria exist, both of which lead to a Tragedy of the Commons, but one is an inferior solution because it leads to assured resource...

This resource update provides an overview of forest resources in Kansas based on inventories conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program of the Northern Research Station. For annual inventory years 2001-2013, the sample length was equal to 5 years. Beginning in 2014, the cycle length was changed to 7 years. For the 2016 inventory, estimates for current variables such as area, volume, and biomass are based on 8,719 field plot samples (594 forested) collected from 2011-2016. Change variables, such as net growth, removals, and mortality, are based on...