Environmental Engineering Reference
In-Depth Information
CO
2
levels affect the length of the pollen season and the characteristics of
the plans themselves, with some species shown to increase their pollen-
producing capacity and even their toxicity. {5.6}
Ecology and Ecosystems
For at least the past 40 years, many species have been and are currently
shifting the phenology (timing) of spring events in concert with warming
temperatures.
Examining 542 species of plants and 19 of animals, a large
phenology (e.g., timing of blooming, egg laying, migrating) study of 21
European countries for the last 30 years of the 20th century found a total
of 78% of species were shifting their spring phenology earlier and only 3%
were shifting later. When combining all species showing change along with
those in the same areas not showing a measurable change, species on aver-
age were found to change ~2.5 days per decade. Throughout the Northern
Hemisphere the similar change was reported to be 2.3 days per decade. The
magnitude of the change occurring only in those species showing a change
on average was ~4 to ~5 days a decade. {5.7}
As the climate has warmed many species have been and are continu-
ing to track this warming by shifting their ranges into areas that before
warming were less hospitable due to cooler temperatures.
Terrestrial species
are moving toward the poles and up in elevation, while marine species are
generally moving down to deeper waters. The average shift over many types
of terrestrial species around the globe was about 6 km per decade. {5.7}
Historically, extinctions of most species have been found to be due
to various stresses, such as land-use change, invasive species, and hunt-
ing, but now the vulnerability of many species to extinction is enhanced
with the added stress placed upon them by climate change.
Those species
more prone to becoming in danger of extinction include those that have a
maximum dispersal distance shorter than the distance to the closest “cool
refuge” and those that are not a good colonizer and hence fail to become
established in these cooler locations. {5.7}
