Treesearch

The Pacific Southwest Region of the U.S. Department of Agriculture, Forest Service (USFS), in collaboration with the USFS Pacific Northwest and Pacific Southwest Research Stations and the Office of Sustainability and Climate, formed a science-management partnership and conducted a climate change vulnerability assessment for infrastructure and recreation in Sierra Nevada national forests. The vulnerability assessment set the stage for developing adaptation options in a series of science-management workshops. The outcomes of the effort, called the Sierra Nevada Infrastructure and Recreation...

In what ways do plant diseases affect forest sustainability? How will disease disturbance regimes change given global warming and increasing population pressures? In this chapter, we review how plant diseases, caused by both biological pathogens and abiotic disturbance agents, influence forest sustainability—but note that our findings derive less from data and more from observations and professional judgment. Many forest pathogens (fungi, bacteria, viruses, nematodes) are microscopic, which predisposes them to nondetection because they cannot be seen with the naked eye and their symptoms...

Bats are renowned for their sophisticated echolocation. However, recent research has indicated that bats may be less reliant on echolocation than has long been assumed. To test the hypothesis that bats reduce their use of echolocation to avoid eavesdropping by conspecifics, we deployed miniature tags that recorded ultrasound and accelerations on 10 wild hoary bats (Lasiurus cinereus) for one or two nights. This resulted in 997 10-s recordings. Bats switched between periods predominated by their typical high-intensity echolocation, or periods predominated by micro calls (unusually short,...

At the 1971 meeting North American Society for Bat Research (NASBR) in Albuquerque, Don Wilson and James S. Findley presented “Randomness in Bat Homing.” The central tenet of their paper was that homing ability in bats could be explained by chance alone or by some sort of random search [Wilson and Findley (Am Nat 106:418–424, 1972)]. In this retrospective, we assess the knowledge gained from, but also the limitations of, older studies on bat homing and review the advances in our understanding of homing and navigation in bats. Although we have learned much over the last half-century about...

In the past several decades, field studies have shown that woody plants can access substantial volumes of water from the pores and fractures of bedrock1-3. If, like soil moisture, bedrock water storage serves as an important source of plant-available water, then conceptual paradigms regarding water and carbon cycling may need to be revised to incorporate bedrock properties and processes4-6. Here we present a lower-bound estimate of the contribution of bedrock water storage to transpiration across the continental United States using distributed, publicly available datasets. Temporal and...

Understanding why diversity sometimes limits disease is essential for managing outbreaks; however, mechanisms underlying this ‘dilution effect’ remain poorly understood. Negative diversity-disease relationships have previously been detected in plant communities impacted by an emerging forest disease, sudden oak death. We used this focal system to empirically evaluate whether these relationships were driven by dilution mechanisms that reduce transmission risk for individuals or from the fact that disease was averaged across the host community. We integrated laboratory competence measurements...

Ecological forecasts will be best suited to inform intervention strategies if they are accessible to a diversity of decision-makers. Researchers are developing intuitive forecasting interfaces to guide stakeholders through the development of intervention strategies and visualization of results. Yet, few studies to date have evaluated how user interface design facilitates the coordinated, cross-boundary management required for controlling biological invasions. We used a participatory approach to develop complementary tangible and online interfaces for collaboratively forecasting biological...

During secondary growth, forest trees can modify the anatomy of the wood produced by the vascular cambium in response to environmental conditions. Notably, the trees of the model angiosperm genus, Populus, reduce the risk of cavitation and hydraulic failure under water stress by producing water-conducting vessel elements with narrow lumens, which are more numerous and more interconnected with each other. Here, we determined the genetic architecture of vessel traits affecting hydraulic physiology and resilience to water stress. Vessel traits were measured for clonally replicated genotypes...

To inform management and conservation of the species, we investigated the distribution of anadromy and residency of steelhead/rainbow trout (Oncorhynchus mykiss) in the Eel River of northwestern California. We determined maternal anadromy versus residency for 106 juvenile O. mykiss using otolith microchemistry. To attempt to relate patterns of anadromy with environmental factors known to influence its distribution in O. mykiss in other places, fish were collected from 52 sites throughout the drainage covering a range of stream size (0.1–7.7 m3 /s estimated mean annual run-off) and distance...

Accurate information on reproductive ecology is necessary to develop conservation actions for at-risk wildlife species. Our objective was to describe female reproductive parameters and den use of two subspecies of wild, untrapped Pacific martens (Humboldt marten, Martes caurina humboldtensis; Sierran marten, M. c. sierrae) of conservation interest in California. We used radio telemetry and remotely triggered cameras to monitor 10 Humboldt martens (2014 to 2016) and six Sierran martens (2016 to 2017) over 23 total denning periods. For Humboldt martens, mean parturition date was 13 April,...