IMPACT AND MANAGEMENT OF MULTIPLE
STRESSORS ON DEMOGRAPHY OF RARE AND ENDANGERED PLANT SPECIES
Background
Forests in the
eastern United States have undergone dramatic changes, and many plant species
now exist in isolated or small populations and are considered threatened,
endangered or of special concern (TES).
Threats to long-term survival range from general habitat loss and
fragmentation, to overabundant whitetailed deer populations, to invasive plants,
animals, and diseases, acid rain, nutrient deposition, and climate change.
Ideally, any management of plant populations or of various threats would
be informed by (1) an analysis of the severity of a particular threat or of the
cumulative threat posed by various stressors and (2) how a particular plant
species/population responds to management of different stressors.
Unfortunately, such guidelines are rarely available to land managers.
Objective
In a new project
started in 2008, we are evaluating the contributions of native whitetailed deer
and introduced species (plants, earthworms, slugs, and root feeding weevils) and
increased nutrient deposition on demography of rare and endangered plant
species. We are using Life Table
Response Experiments (LTRE) manipulating the abundance of various stressors in
field and common garden experiments to assess their contribution to demography
of select plant species. In
addition we will experiment with various restoration techniques to assess the
possibility to restore depauperate or invaded areas under various stress
scenarios.
Expected Outcomes:
While we have
abundant evidence for the “ecosystem engineering” ability of deer or slug
herbivory, plant or earthworm invasions, or nutrient deposition, our work will
for the first time combine an assessment of these different stressors into a
single study or model. At present,
land managers have little quantitative evidence to support different management
activities aimed to maintain T&E species.
Should the focus be control of introduced plant species, prevention of
earthworm invasion, control of the deer herd, or reductions in nutrient inputs?
Our work aims to illuminate the severity of different stressors alone and in
combination to allow prioritization of management efforts.
Contributors/Performers
Bernd Blossey,
Amy Blair,
Evan Cooch, DNR,
Victoria Nuzzo, Natural Area Consultants
Sponsor
Strategic Environmental Research and Development Program