Reports of encounters between people and generalist urban‐adapted carnivores are increasing around the world. In North America, coyotes Canis latrans are among the carnivores that appear to be especially capable of incorporating novel anthropogenic food types, including those found in cities. Consuming anthropogenic food may benefit coyotes by increasing their dietary diversity, but it may also lead to increased interactions and conflicts with humans. To test these hypotheses, we compared the diets of urban and rural coyotes from two urban and three rural sites spanning 32 200 km2 in Alberta, Canada. We analyzed scat samples to calculate diet diversity at the level of both individuals (species per scat) and populations (Shannon index) and to determine the frequency of anthropogenic food consumption. We complemented this comparison with stable isotope analyses of hair samples taken from individual urban and rural coyotes that were or were not reported by the public for repeatedly visiting backyards and schoolyards during the day. Relative to rural coyotes, urban coyotes had more diverse diets at the level of both individuals and populations, consumed anthropogenic food more often, and animals less often, than rural coyotes. Although urban coyotes assimilated more anthropogenic food than the rural coyotes overall, the urban coyotes reported for conflict assimilated less protein and were more likely to be diseased. Our results suggest that processed anthropogenic food may contribute to the success of urban coyotes, but does not entirely correlate with conflict. Instead, some seemingly innocuous, but low‐protein food sources such as bird feeders, compost, and cultivated fruit trees may contribute disproportionately to encounters with people for coyotes and other urban‐adapted opportunistic carnivores.
The location and physical characteristics of 32 occupied swift fox (Vulpes velox) natal/rearing dens and 33 unoccupied sites in southeastern Alberta and southwestern Saskatchewan, Canada, were compared in 1991 and 1992. Comparisons between occupied and unoccupied sites were restricted to eight habitat variables that described the orientation of each den entrance, mean height of old and new grass, number of holes in each den complex, den position and slope (i.e., incline of the land) in relation to hills, and distance to the nearest roadway and water source. Two-sample t tests and Mann-Whitney U tests indicated that occupied sites were located on the tops of hills, close to roads, and in places where old grass was significantly higher than at unoccupied sites. Den entrance angles did not differ between occupied and unoccupied sites. A stepwise discriminant function analysis identified five potential discriminators of occupied and unoccupied sites (i.e., position on a hill, height of new grass, distance to water, distance to roads, and slope). Den position was the variable that discriminated most strongly between occupied and unoccupied sites. Occupied sites were located predominantly on the tops of hills. The quadratic discriminant function had an overall classification success of 83.1%. Based on the five habitat variables, the discriminant function model correctly classified 28 of the 32 occupied sites as being occupied (87.5%) and 26 of the 33 unoccupied sites as being unoccupied (78.8%). The habitat variables identified by the discriminant function model may be a useful tool for selecting and modifying release-site characteristics and creating more realistic live-rearing facilities.
Sagebrush (Artemisia) is a vital habitat component for many grassland species and continued loss, fragmentation, and degradation of sagebrush habitats has increased the need for their restoration. Conventional revegetation methods have resulted in extremely low plant establishment and survival inhibiting the success of sagebrush restoration efforts. During greenhouse production, we sought to improve Artemisia cana seedling quality and post‐planting growth and survival by increasing tissue nutrient content. We conducted a preliminary 12‐week greenhouse study and a subsequent 26‐week greenhouse + 2‐season field study, investigating 12 nutrient loading treatments (application of 70, 105, 175, and 245 mg nitrogen [N] plant−1 at single, constant, exponential, and modified exponential rates). Nitrogen content of seedling leaves and roots at 26 weeks indicated that application of 175 and 245 mg N plant−1 on exponential or modified exponential dosing schedules resulted in nutrient‐loaded seedlings. Seedlings were planted into a cleared plot in Grasslands National Park, SK. After 60 weeks in the field, nutrient‐loaded seedlings had significantly greater survival (75%) than non‐loaded seedlings (65%) and greater crown area (1,351 vs. 1,004 cm2). Rhizomatous reproduction (sprouting) occurred within 4 weeks of planting. New sprouts had disproportionately larger crown areas (2,237 cm2) and greater survival (86%) than planted seedlings. Nutrient loading was an effective method to overcome high mortality that has inhibited restoration outcomes. Where plant materials and resources are limited, nutrient loading could be especially useful by improving seedling survival and crown area without increasing planting densities.
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