An additional challenge for parentage analysis is that it requires exhaustive sampling and so is practical only over small spatial scales (less than 10 km) and low densities. Even extraordinary examples of this type of work include only about 1000 trees in isolated populations (Lesser & Jackson 2013). The continental distributions of dense coniferous forests do not lend themselves to these methods.
[C]ertain genotypes are evolutionarily inaccessible under rapid environmental change. Rapidly deteriorating environments not only limit mutational opportunities by lowering population size, but they can also eliminate sets of mutations as evolutionary options.
From Lindsay et al. 2013
Jeremy Fox and Brian McGill answer a question of mine over at Dynamic Ecology.
What jobs outside of academia are eco-evo PhDs best qualified for? If you quit your academic scientist job, what would you do next?
One day humans might be competing with trees for water:
It is likely that the northern Great Plains will become
hotter, which will increase evaporation rates and result in drier conditions. It is also likely there will be more extreme weather events, such as longer and more-intense droughts that could lead to new Dust Bowls or more intense rain events that increase the potential for erosion. Projected vegetation shifts such as the expansion of eastern deciduous forests westward and the increase in woody life forms in the Great Plains depend on the effect of increased atmospheric CO2 concentration that would enhance the water-use capacity of trees, which could mitigate drought stress. Unlike grasses, deeper-rooted trees under drought conditions would also depend for their survival on the persistence of the deep aquifer, which would be even more severely taxed by human activities in the region as rainfall becomes scarce. [1] [emphasis mine]
1. Wiens, J. A. & Bachelet, D. Matching the multiple scales of conservation with the multiple scales of climate change. Conservation biology 24, 51–62 (2010).