Justin Garwood

• BS Fisheries Biology, MS Wildlife Biology-Cal Poly Humboldt
• Environmental Scientist (Fisheries) at California Department of Fish and Wildlife

The pervasive and unabated nature of global amphibian declines suggests common demographic responses to a given driver, and quantification of major drivers and responses could inform broad-scale conservation actions. We explored the influence of climate on demographic parameters (i.e., changes in the probabilities of survival and recruitment) using...

The Trinity Alps is a compact glaciated subrange of the Klamath Mountains in northwest California with elevations < 2,750 m making it a unique location in the western US to study glacier change. We examined glacier change since the last Little Ice Age advance in the late 19th century by mapping historic glacier areas using clearly defined moraines....

Sex-related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influences on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males)...

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 population...

This book celebrates the natural history of the Klamath Mountains of northwest California and southwest Oregon through stories of diversity and resilience over deep time. Shaped by geology, these mountains form an ancient jigsaw puzzle and topographic mosaic dissected by big-shouldered river canyons and sharp ridgelines that create localized clima...

We describe arboreal habitat use by Aneides vagrans in a western redcedar (Thuja plicata). Our observations show these salamanders make use of trees with complex crowns that have some interstitial decay.

For species with complex life histories, climate change can have contrasting effects for different life stages within locally adapted populations and may result in responses counter to general climate change predictions. Using data from two, 14-year demographic studies for a North American montane amphibian, Cascades frog (Rana cascadae), we quanti...

This is a 2023 project status update for the restoration component of our mountain lakes amphibian and fisheries management program. This report is focused on fish removal progress during the summer of 2023 across 8 restoration waters. This report does not cover amphibian population status and trend monitoring which is ongoing and will be reported...

An observation of an Ambystoma macrodactylum (Long-toed salamander) larva predating on an Anaxyrus boreas (Western Toad) larva.

Coastal Tailed Frogs (Ascaphus truei) range across the Pacific Northwest from northern California, USA, into British Columbia, Canada, and from sea level to >2,131 m. Previous work has shown a variable larval period but has not clearly separated elevational from latitudinal effects. Therefore, we examined size at beginning of metamorphosis, larval...

This research note documents a leucistic coloration pattern in larval Cascades Frogs.

Snake foraging competition between two sympatric garter snake species on an adult Cascades Frog (Rana cascadae) in the Trinity Alps Wilderness, Trinity County, Klamath Mountains, California.

Life-history information sets the foundation for our understanding of ecology and conservation requirements. For many species, this information is lacking even for basic demographic rates such as survival and movement. When survival and movement estimates are available, they are often derived from mixed demographic groups and do not consider differ...

These are the Abstracts of the 2019 annual meeting of SNVB, WA TWS, and NW PARC. I have two abstracts in this compilation: Olson et al., Density Management and Riparian Buffer Study update, pp 154-155; Weil and Olson, NW PARC update, pp 162-163.

I initiated this study in 2013 to determine current occupancy status and spatial distributions of salmonids, among other species, occurring in Elk Creek. This study should provide landowners, managers, and restoration groups better information on the aquatic species occurring in Elk Creek while identifying remaining information gaps. I used opportu...

We used spring outmigrant trapping data to estimate the abundance of salmonid smolts emigrating from Mill Creek, Smith River (California), over four years from 2014 to 2017. Mill Creek has one of California’s longest running salmonid outmigrant trapping programs dating back to 1994 and we summarize abundance estimates across the 24 years. We also e...

We investigated two essential population viability metrics of salmonids over five consecutive years in the Smith River basin (Oregon and California), with ESA listed coho salmon as the focal species. First, we monitored adult salmonid escapement and distribution from 2011 to 2016 using live fish, carcass, and redd counts as defined in California's...

Properly functioning estuaries are complex systems where aquatic organisms benefit from a variety of spatial and temporal niches. This is especially evident for Pacific juvenile salmonids, where studies have shown estuarine habitats can be more productive and can lead to greater growth and survival compared to those derived from natal stream habita...

Recent studies have shown the broad role estuaries play in juvenile coho salmon (Oncorhynchus kisutch) life history; however, most of these studies were limited to the Pacific Northwest and did not include information from the southern end of its range in California. We sampled the stream-estuary ecotone (SEE) of numerous Humboldt Bay tributaries f...

Water temperature can have a profound influence on aquatic species distributions, physiology and growth rates, and disease. These factors are especially important to consider for sensitive salmonid species. We established water temperature monitoring in the Smith River to define baseline spatial and temporal thermal conditions during the summer mon...

In California, River Otters (Lontra canadensis) are most commonly associated with food-rich lowland aquatic habitats where they forage primarily on fish and crustaceans. Their distribution in high-elevation montane regions of the state, areas in which fish and crayfish were absent historically, is largely unknown. We compiled occurrence records of...

State and federal agencies are tasked to recover Coho Salmon populations to a level where the risk of extinction is negligible. Thus, bold recovery actions and robust population monitoring programs are needed. This updated list of 542 Coho Salmon streams provides the best available synthesis of known historic and current Coho Salmon distribution in...

The vast quantity of information compiled during this investigation could not be reasonably distilled into a single report. Rather, it was decided a separate data document providing all evidence supporting coho salmon presence in individual streams within the California portion of the Southern Oregon Northern California Coho Salmon Evolutionary Sig...

We developed a procedure for constructing an unbiased reach‐based sampling frame using a geographic information system (GIS) specifically for adult salmonid spawner ground surveys within Chinook and coho salmon and anadromous steelhead spawning distributions. This procedure provides a methodology for generating a sample frame of defined stream reac...

Given the current global amphibian decline, it is crucial to obtain accurate and current information regarding species distributions. Secretive amphibians such as plethodontid salamanders can be difficult to detect in many cases, especially in remote, high elevation areas. We used molecular phylogenetic analyses to identify three partially digested...

We studied summer use of high elevation lakes by American Dippers (Cinclus mexicanus) in the Trinity Alps Wilderness, California by conducting repeated point-count surveys at 16 study lakes coupled with a 5-year detailed survey of all available aquatic habitats in a single basin. We observed American Dippers during 36% of the point-count surveys an...

Hyperpredation occurs when non-native prey facilitate invasive predators, which then suppress native prey. Direct impacts of introduced fish on amphibians are well studied, but the role of fish in supporting shared predators has not been considered. We present evidence for indirect effects of trout on amphibians through snake predation. Analyses of...