Geoscience Reference
In-Depth Information
sheets, and this can limit the populations' available gene pools
and subsequent abilities for genetically adapting to new cli-
matic conditions. Capturing genetic diversity becomes increas-
ingly important since it is possible that populations will lose
genetic diversity in response to the changing environment.
Researchers have found that some cold-adapted plant spe-
cies in alpine environments have begun to gradually climb
higher up mountain summits—a phenomenon correlated with
warming temperatures (Held et al. 2005). In some cases, these
plants migrate upward until there are no higher areas to inhabit,
at which point they may be faced with extinction. Additionally,
the upward migration of plant species can lead to increased
competition for space and resources, causing further stress
among alpine plant populations.
A Global team found that useful Tibetan plants (predomi-
nantly medicinal plants) accounted for 62% of all plant spe-
cies in the alpine Himalayan sites that they examined. Further,
although overall species richness was found to decline with
elevation from the lowest summits to the highest, the propor-
tion of useful plants stayed approximately constant. This high
percentage of useful plants confirms the importance of the
Himalayas for Tibetan medicine and reflects the dangers posed
by potential plant losses from climate change.
However, a few medicinal alpine species are restricted to
the upper alpine zone, such as
Artemisia genipi
(Asteraceae)
and
Primula glutinosa
(Primulaceae). These species may expe-
rience greater impacts from warming temperatures, possibly
leading to local endangerment.
Medicinal and
aromatic plants
in other
threatened
regions
Although Arctic and alpine areas are experiencing some of the
most rapid changes from global warming, other ecosystems are
also considered particularly threatened by the ongoing effects
of climate change. Among these ecosystems are islands and
rainforests. Islands are considered especially at risk from rising
ocean levels, in addition to changing temperatures and weather
patterns. The world's oceans also absorb excess heat from the
atmosphere, and as water warms it expands in volume (a pro-
cess known as thermal expansion), which will similarly con-
tribute to global sea level rise.
Despite these threats, experts have indicated that island
MAPs may not be significantly affected by conditions related to
climate change. Many of the plants used by island communities
are common species that are widespread and highly adaptable.
Common medicinal plants of the Pacific islands include
noni (
Morinda citrifolia
, Rubiaceae), naupaka (
Scaevola
spp,
