Publications

Executive Summary The purpose of this report is to provide the Marine Corps with an annual summary of the distribution, abundance, and breeding activity of the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus; flycatcher) at Marine Corps Base Camp Pendleton (MCBCP or “Base”). Surveys for the flycatcher were conducted on Base between May 8 and July 24, 2024. All of...

Joshua trees (Yucca brevifolia and Yucca jaegeriana) are iconic, foundational species of the Mojave and Sonoran Deserts in North America. Due to their ecosystem importance, long generation times, and low resilience to disturbance, these hybridizing sister species are increasingly the focus of conservation efforts. Predicting Joshua tree responses to impending climate variability, along...

Introduced organisms can cause substantial effects across most landscapes. Island ecosystems, especially tropical islands, are at elevated risk from introduced organisms. The risks are even higher for tropical islands with moderate or high levels of transit, yet this can be minimized by application of appropriate biosecurity requirements. In this study, we examined the potential for non...

Background Severe fire weather is becoming more common throughout the western United States. Changing conditions demand a better understanding of how prescribed fire treatments perform under extreme burning conditions, including the interactive influence of the age of treatments, vegetation, and fire weather. The Carr Fire of July 2018 burned nearly the entire land area of Whiskeytown...

We surveyed for Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at select locations along the San Luis Rey River, including along the middle San Luis Rey River near Bonsall and the upper San Luis Rey River near Santa Ysabel, California, in 2024. Surveys were completed at six locations: two along the middle San Luis Rey River (Bonsall [BO] and Rincon), which were...

The majority of plants rely on animal-mediated pollination for reproduction. Reductions in pollinator visitations can lead to pollen limitation and declines in seed production. Arctomecon californica, the Las Vegas bearpoppy, is a rare plant native to the northeastern Mojave Desert. It is pollinator dependent for reproduction as it is self-incompatible, but associated pollinator...

Robust science is needed to inform national resource management and policy decisions. Predictive species habitat maps are frequently employed in conservation decision-making but are often based on a single metric representing habitat quality. We outlined a framework that combines multiple spatially explicit indices of potential habitat quality that could be used to identify and...

At Redwood National and State parks restoration efforts are underway to promote the recovery of forests following a history of intense logging. Unmanaged secondary forests at the parks have high stem density with slow stand development. Restoration thinning treatments of these stands are designed to promote the representation of redwood and improve the growth of residual trees...

We surveyed for Least Bell’s Vireos (Vireo bellii pusillus; vireo) and Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at the Mojave River Dam study area near Hesperia, California, in 2024. Four vireo surveys were completed between April 17 and July 2, 2024, and three flycatcher surveys were completed between May 23 and July 2, 2024. We detected three territorial...

The Klamath Network, comprising six national park units in northern California and southern Oregon, initiated a vegetation monitoring protocol in 2011 to discern ecologically significant vegetation trends in these parks. The premise of the protocol is that multivariate analyses of species composition data is the most robust means for early detection of vegetation change over time. Here...

The sea star Pisaster ochraceus and sea otters (Enhydra lutris) are two predators capable of shaping rocky intertidal and kelp forest community structure and functioning. In 2013, a sea star wasting event decimated populations of Pisaster along the west coast of North America. The collapse of this species in the rocky intertidal revealed an unexpected relationship between two keystone...

Captive breeding and release programs aimed at recovery of rare species can be informed by genetic data to help select high-diversity source populations, make pairing decisions to minimize inbreeding, and manage release strategies. We developed a set of 54 microsatellite loci to assess genetic structure and diversity across the United States range of the Light-footed Ridgway’s Rail...