A deformed rib from a Columbian mammoth (Mammuthus columbi) was found among more than 100 mammoth bones excavated from an alfalfa field at the Tonnemaker Hill Farm in the Frenchman Hills north of Royal City, Grant County, Washington. The mammoth remains were deposited within fine-grained Missoula flood sediments sometime after 16 ka. We performed a detailed examination of the rib, including computerized tomography imaging, and investigated the possible etiology of the deformity. The deformity consists of hypertrophic bone formation localized toward the distal (sternal) end of the rib. The circumference of the lesion is nearly twice that of the medial circumference of the rib diaphysis. This lesion is consistent with an incompletely healed fracture or a fracture nonunion with pseudarthrosis (false joint) formation. Gross examination and computerized tomography scan images of the proximal aspect of the rib, as well as cursory inspection of the other skeletal remains, have yet to reveal definitive evidence of other bony abnormalities. We surmise, therefore, that this fracture was the consequence of blunt force trauma in a healthy animal. To our knowledge, this is the first report of a rib fracture with incomplete healing or false joint formation in a M. columbi individual in the Pacific Northwest. We suspect the incidence of rib fractures among M. columbi was greater than the Pacific Northwest literature suggests and encourage examination of existing collections for evidence of similar findings. The incidence and frequency of such injuries may provide insight into M. columbi behavior.

Genetic analyses have become increasingly powerful, more readily available to biologists, and have made ever more degraded DNA potentially useful. Single nucleotide polymorphisms (SNP) are a relatively new “class” of markers that show promise for use with degraded or archived samples. We sequenced a panel of 298 SNPs from Chinook salmon (Oncorhynchus tshawytscha) tissue in three comparative studies to determine the effect of DNA quality at sampling, time in archive, and tissue type and preservation method on SNP genotyping success using logistic regression. The first study evaluated pristine DNA from live adults sampled at three hatcheries and archived up to 6 years. The second study compared samples from carcasses with varying levels degradation (i.e., condition) and archived up to 15 years. The third study compared heart and fin samples preserved either in ethanol or on paper from carcasses with varying levels of degradation and processed within 6 months. Genotyping success for fresh tissue did not decline over the 6-year archive period at two of the three hatcheries, suggesting sample handling techniques may be more influential than time in archive. Genotyping success of archived carcass samples depended more on carcass condition than time in archive. Heart tissue genotyped consistently more often than fin samples from all but poor condition carcasses. Based on these results, we make tissue-sampling recommendations for different intended purposes. We also provide simple, post-collection sample handling procedures that can increase genotyping success regardless of tissue or preservation method.

Climate-growth relationships in altitudinal treeline forests are particularly informative because they represent the upper limit of a species range where growth is often especially sensitive to climatic variation. Radial growth response to climatic variables typically ranges from energy limited to water limited. In the Pacific Northwest region of North America, treeline forests are typically energy limited. Results from a recent study (Marcinkowski et al. 2015) indicate a change in climate-growth relationships over time in treeline mountain hemlock (Tsuga mertensiana) in northern Washington state. Here, we investigate whether these same relationships hold across 700 km of the range of treeline mountain hemlock in Oregon and Washington. Using cores from trees > 200 years old, we examined temporal and spatial variability of climate-growth relationships since the early 20th century. Results indicate 1) a potential weakening of energy limitation in forest growth at treeline, 2) a nonstationary growth response to climate variables through time, and 3) different patterns of growth response to climate from north to south. Climate-growth relationships were generally similar between different aspects in the same geographic location, with some exceptions. Correlations between climate variables and radial growth differ over time (ranging from significantly positive to significantly negative), indicating the non-stationary nature of climate-growth relationships. These results identify where changes in growth-limiting variables may be occurring at treeline. Additional changes in the effects of climate change on growth at treeline are expected, and may be temporally complex.

Establishment of trees in subalpine meadows is a potential indicator of ecological effects of climate change. Tree establishment is a multi-year process including cone and seed production, germination, establishment, and growth, with each demographic step possibly sensitive to different climate limitations. While most studies have focused on one or a few steps, this study follows a cohort of individually marked saplings for 27 years beginning as seeds in two meadows on Hurricane Ridge, Olympic National Park. These meadows are examples of a south-facing tall sedge community type rather than the north-facing heath-shrub type where establishment has usually been observed. Results showed that mortality was high for the first few years, but number of saplings stabilized after the first decade. Seedling mortality during germination and establishment was directly related to weather that resulted in high air and soil temperatures and drought, while mortality of established saplings was indirectly related to weather through effects on growth. Growth was enhanced by longer growing season and warmer minimum temperatures; growth over three years and sapling height were predictive of mortality. Most sapling survival occurred in lichen (primarily Trapeliopsis granulosa) and Vaccinium deliciosum plant communities. Many saplings are growing at very low rates compared with the rate predicted from adult trees. It is also apparent that while microsite within meadow (e.g., relative snow depth) is important in determining sapling success, the landscape position of meadows (e.g., north versus south aspect) exerts a higher-level control over whether a subalpine meadow is likely to disappear with warming climate.

Estimating salmonid habitat capacity upstream of a barrier can inform priorities for fisheries conservation. Scott Dam in California's Eel River is an impassable barrier for anadromous salmonids. With Federal dam relicensing underway, we demonstrated recolonization potential for upper Eel River salmonid populations by estimating the potential distribution (stream-km) and habitat capacity (numbers of parr and adults) for winter steelhead trout (Oncorhynchus mykiss) and fall Chinook salmon (O. tshawytscha) upstream of Scott Dam. Removal of Scott Dam would support salmonid recovery by increasing salmonid habitat stream-kms from 2 to 465 stream-km for steelhead trout and 920 to 1,071 stream-km for Chinook salmon in the upper mainstem Eel River population boundaries, whose downstream extents begin near Scott Dam and the confluence of South Fork Eel River, respectively. Upstream of Scott Dam, estimated steelhead trout habitat included up to 463 stream-kms for spawning and 291 stream-kms for summer rearing; estimated Chinook salmon habitat included up to 151 stream-kms for both spawning and rearing. The number of returning adult estimates based on historical count data (1938 to 1975) from the South Fork Eel River produced wide ranges for steelhead trout (3,241 to 26,391) and Chinook salmon (1,057 to 10,117). An approach that first estimated juvenile habitat capacity and then used subsequent life stage survival rates yielded 1,281 (CV 56%) steelhead trout and 4,593 (CV 34%) Chinook salmon returning adults. Variability in estimated fish numbers reflects application of densities and survival rates from other populations, assumptions about salmonid productivity in response to potential spawning habitat capacity, residency and outmigration of early life-stages, summertime water quality conditions, and inter-annual hydrograph, marine, and population variability.