Regions with an EI≤10 are very stressful and unlikely to support a population, while an EI>20 is favorable for population growth and an EI>30 represents a region able to support substantial population densities [24], [25], [26].
Despite substantial fluctuations in population density [ 24, 45], the species does not show any typical phase polymorphism [ 26].
For example, there are substantial differences in population density across Canada, with marked north-to-south increases in density – approximately 80% of Canadians live within 160 km of the Canada–United States border [ 23] – and there is marked intra-provincial urban rural variability [ 24].
China, east coast [cartographic material] : population density.
There is substantial evidence showing that the population density of endophytes depends on the host genotypes (Singh et al. 2009).
The Arabian Peninsula has had a relatively low population density, and substantial demographic backflow to the Near East is improbable.
Across taxa we find substantial amounts of evidence for population density influencing the location of adaptive peaks for a range of traits, and, in the presence of frequency dependence, changing the shape of selection (stabilizing versus disruptive).
Nest decay times vary substantially over time and among sites and can introduce substantial errors in estimates of orangutan population density [12], [13].
Also, the Atlanta model — with only about 1/4 Boston's weighted population density — arguably leads to substantial external costs: more greenhouse gas emissions, in part because of slightly longer commutes, in part because of much lower use of public transit.
However, the importance of these gradients was to a large extent attenuated by municipality population density, indicating that a substantial part of the importance of geographical gradients was linked to population density.
