Treesearch

Context Wildlife responses to disturbance may include physiological stress responses that are often difficult to observe yet important for wildlife health. Coupling physiological biologgers with tracking data can identify anthropogenic features associated with stress responses. Diagnosing when, where, and the response to stressors, along with how species may habituate or sensitize to stressors over time, is crucial for conservation efforts. Objectives We examined if mule deer (Odocoileus hemionus) exhibited acute stress responses to road crossings, identified the road features and contexts...

Droughts are intensifying across the biosphere, yet the consequences of this phenomenon for wildlife habitat suitability and fitness are poorly studied. We analyzed 12 years of GPS telemetry data for three large mammal species—herbivorous mule deer ( N = 2854), omnivorous black bears ( N = 103), and carnivorous cougars ( N = 105)—to evaluate the effects of drought on each species’ habitat selection across a 500,000-km 2 aridity gradient in the interior West, USA. Additionally, we evaluated interannual variation in mule deer reproduction as a function of drought intensity. Severe drought...

Background An important, yet often overlooked component of animal movement behaviour is the physiological cost incurred by animals when travelling through an environment, i.e., the “energy landscape”. These include the costs related to movement rate and elevation gain, as well as the mediating influence of variation in cover types and substrate. These costs are likely to be mediated by differences among individuals, with body condition and age likely to modify energy expenditure. Methods Using subcutaneous biologgers paired with GPS collars (n = 37), we recorded high-resolution heart rate...

Body condition shapes ungulate survival and reproduction, but temporally sparse capture-based measurements limit inference about when individuals gain or lose fat reserves in response to environmental change. We evaluated implanted biologgers that measure bioimpedance, based on the electrical conductivity of tissue, as a continuous signal of body condition dynamics in captive elk. Adult female elk (n = 4) were implanted with subcutaneous biologgers that recorded bioimpedance every 4 h during a ~6-month feeding experiment inducing gradual condition loss and recovery. We quantified correspond...

Gravel‐bed rivers adjust their shape in response to environmental changes, including the addition or removal of macro‐roughness like logs and boulders. River restoration often involves adding macro‐roughness to reduce flow velocity and increase channel‐floodplain connectivity, but our understanding of channel response to changes in macro‐roughness is limited, in part because of a lack of theory that links macro‐roughness to reach‐scale channel evolution. We ask how macro‐roughness affects gravel‐bed river geometry, and how rivers respond to step changes in macro‐roughness as might occur...

Soil and stream nitrate (NO3−) concentrations often increase after severe fire from elevated nitrogen (N) mineralization and reduced plant uptake. However, it is unclear how long these effects persist and contribute to stream N export.We examined the contribution of soil N supply and vegetation N demand to 19-fold higher stream NO3− export that has persisted since the 2002 Hayman Fire in Colorado, USA.We compared soil N pools, inorganic N production, subsurface (0–100 cm) NO3− concentrations, vegetation cover, productivity and N demand 17 years post-fire. We sampled along burned and...

Forested ecosystems are vulnerable to wildfires which have short- and long-term effects on downstream water quality, including changes to dissolved organic carbon (DOC) transport and disinfection byproduct (DBP) formation downstream, which can be exacerbated by high-intensity rainstorms. To evaluate short-term changes to streamwater composition and characteristics, we sampled three streams feeding into the Cache la Poudre River within the perimeter of the 2020 Cameron Peak Fire before, during, and after the first postfire summer storm season. Streams were distinguished by the proportion of...

Forest restoration in Hawaii is underway due to past large‐scale conversion of forests to pastures dominated by invasive grasses. Secondary succession is limited by grass dominance and a lack of native seed rain, making outplanting a viable restoration strategy.We conducted a multi‐year field experiment at Hakalau Forest National Wildlife Refuge to test how species richness and planting density influence outplant survival, cover, and growth.We planted eight native species representing trees, a shrub, a fern, and a vine in combinations of two, four, and eight species at single and double...

Prairie sunflower is considered native to western NorthAmerica but now occurs nearly throughout the US andCanada, although “efforts to delimit [its] naturalboundaries before the appearance of man and subsequentspread as a weed meet with little success” (Heiser 1947). Subspecies petiolaris occurs nearly throughout theconterminous United States and in British Columbia,Alberta, Saskatchewan, Manitoba, and Ontario, Canada(Schilling 2006; MacKinnon et al. 2014). Subspecies fallax occurs in Nevada, Utah, Colorado, and Arizona (Schilling2006).

Common sunflower is native to western North America, butbecause of escaped crop, horticultural, and forage cultivarsit now has a widespread North American and worldwidedistribution (Schilling 2006; Hitchcock and Cronquist 2018).Hybridization and introgression have also contributed tothe expanding distribution of common sunflower (Heiser etal. 1969). In the United States, it occurs in all states butAlaska. It is common on dry sites west of the MississippiRiver, and grows outside of cultivation in eastern states(Harrington 1967; Munz and Keck 1973; Weber 1976;Schilling 2006; Hitchcock and...