The ecology of urban ecosystems profoundly influences the plants and animals that live in and near cities, and even changes how birds sing – to read more about this, see here:
The eastern gray squirrel (Sciurus carolinensis) is ubiquitous in Philadelphia today, and in many other cities as well. However, this was not always the case.
To read more about these little mammals, and how, when and why they came to be so citified, see here:
The entire paper mentioned in the linked-to article above is here:
And for a bit more on squirrels in Philadelphia, see within this page:
and this one:
On the evening of Thursday the 19th of December, 2013, beginning at 7:30PM, the Philadelphia Botanical Club will have its monthly meeting, and Ken Frank will talk about a common herbaceous annual and its broader impacts on and implications for society, in a lecture titled “Ragweed and Civilization”.
For more information, see here:
To read about how a neighborhood in Philadelphia went from hills, valleys and creeks to streets, houses and underground conduits, see here: