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 By mid- to late century, Illinois summer temperatures are
expected to mimic those of a present-day summer in Texas and
intense droughts and floods will become more common. A group of
scientists at the Illinois Natural History Survey (INHS)
evaluated the climate change vulnerability for all 331 of
Illinois’ threatened and endangered plant species, making
Illinois the first state to review every listed plant.
Findings showed that 88 percent of threatened and endangered
plants are vulnerable to climate change, and 6 percent are
extremely vulnerable. Habitat loss, barriers from land use
change, seed dispersal ability, and sensitivity to changing
temperatures and precipitation are the leading factors.
“A critical component is the barriers that prevent plant species
from migrating to better adapt to changed climate,” said INHS
botanist Greg Spyreas. “Far more habitats have been destroyed in
Illinois than in other states, which makes more man-made
barriers—cornfields, roads, and urban areas—in addition to
natural barriers, such as the Illinois River, that constrain
plants to isolated natural areas.”
Unlike animals, most plants cannot migrate long distances to
offset the effects of climate change. In mountainous states,
such as Colorado, plants need only move a short distance via
seed dispersion to higher elevations to survive. In Illinois,
however, seeds in Champaign may have to disperse to Chicago, for
example, to find suitable habitat, Spyreas said.
Plants that thrive in particular conditions, known as habitat
specialists, are most at risk. Many rare, endangered species
fall into this category. These plants have very little to no
chance of adapting to or surviving in a changing climate.
Assisted migration, or physically moving plants
further north to where they are better suited to the
environment, might be the only way to overcome the dispersal
barriers. This science is still in its infancy, as researchers
must take numerous factors into account to try to predict where
or if assisted migration will be useful.
Perhaps the best approach, the scientists say, is not to target
the most vulnerable of the 331 plants in the state, but instead
to attempt to save those for whom Illinois constitutes the main
portion of their total range—where Illinois has most of their
populations in the world. Another priority are those plants for
which the northern or central part of their range is Illinois.
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“We are now in a crisis, and maybe this is the point
when we need to do triage and prioritize the urgency of threatened
and endangered plant species,” Spyreas said. “Instead of targeting
our resources on trying to save the most vulnerable plants that have
no chance of survival in Illinois because of climate change, we
could focus on the ones that could survive.”
This controversial idea doesn’t mean that plant enthusiasts and
environmentalists shouldn’t keep trying to restore all endangered
plants, but that many factors should be considered when allocating
limited financial resources to protect the large number of plants
that can’t adapt to a warmer climate here.
“Although we want to protect as many organisms as we can, the
reality is that with limited resources we cannot save everything,”
said INHS plant ecologist Brenda Molano-Flores. “At some point we
need to start making the difficult choices.”
Efforts must be directed to assist with preventing more plant
species from reaching a similar fate by protecting and restoring
more natural areas. Financial support is also needed to fill the
knowledge gaps about rare plants’ natural history, ecology, and
genetics to develop conservation and reintroduction programs.
In the short-term, Molano-Flores said she hopes that resource
managers and conservation agencies will consider this prioritization
method as part of their toolbox when making decisions regarding
Illinois endangered plants.
This study was published in the journal Castanea with partial
funding from the Illinois Department of Natural Resources.
[Lisa Sheppard] |
