The Lugg has a large and potentially threatened population of both Atlantic salmon (Salmo salar) and Brown Trout (Salmo trutta).
The patterns of decline are well documented, but the processes that threaten population persistence are poorly understood.
Then, in 1958, the National Park Service asked John to perform a study of the grizzly bears of Yellowstone, which had been reduced to a small, threatened population.
The safety challenge of rocket launches typically requires additional dedicated safety equipment on-board and ground facilities to monitor flight for potentially unsafe conditions and to terminate the flight before the rocket can threaten population centers or critical assets.
American officials believe the missiles have been put in place to strengthen Iraq's defenses in the north and to threaten population centers like Kirkuk and Mosul if the Americans or Kurdish forces capture the cities.
In the Northern Hemisphere, stronger storms dip farther south, so they're more likely to threaten population centers, such as New York City or Chicago.
It allows us to evaluate the likely outcome of different impacts on the population and identify actions that are most likely to favour (or threaten) population persistence.
Many other traits show temperature sensitivity and might threaten population viability, such as sex determination, sexual abnormalities and fertility (Strussmann et al. 2010; Pankhurst and Munday 2011).
Using various modeling techniques, the authors show that, despite plasticity, global warming will create a mismatch between the optimal and realized egg-laying dates, which might threaten population persistence unless it can be closed by genetic evolution.
For instance, in the lizard Lacerta vivipara, male sexual behavior is harmful and male-skewed sex ratios can threaten population persistence (Le Gaillard et al. 1998; see also Low 2005).
