Biology Reference
In-Depth Information
Table 6.1
Techniques involved in forecasting invasions including applications to: early detec-
tion, predicting species spread, data analyses, spatial scales, and taxonomic completeness
Early detec-
tion
Species
spread
Analysis
types
Spatial
scale
Taxonomic
completeness
Data synthesis
None
Past
invasion
rates
Past patterns
of inva-
sion; can
validate
current
methods
Limited by
data that
exists;
large spa-
tial extent,
coarse spa-
tial resolu-
tion
Any spe-
cies with
historic
occurrence
records
Field data
Detect com-
pletely
new spe-
cies in
an area
Field
measure-
ments
Early detec-
tion,
validation
locations,
current dis-
tribution in
small area
Limited spatial
extent; can
resample
through
time; fine
resolution
Single or few
species
Statistical
techniques
Prioritize
survey
locations;
Generate
watch lists;
relies on
field data
and legacy
data
Use field
data to
predict
spread
rates,
distribu-
tion, abun-
dance, etc.
Generate
watch lists,
predict
habitat
suitability,
or potential
abundance
Relies heav-
ily on
field data,
but can
be large
extent and
high reso-
lution
Single to mul-
tispecies
dependent
on tech-
nique
Remote
sensing
Can detect
infestations
of known
species to
a certain
resolution;
requires
some field
data
Temporal
analyses
of imagery
can deter-
mine
spread
rates
Current distri-
butions
Trade off
between
extent and
resolution,
can be cost
prohibitive
Intensive for
single spe-
cies; may
not work
for some
species;
plant cen-
tric
provide insight into the requirements for the establishment and subsequent spread
of invasive species that can be applied to current invasions. Perhaps by examining
these types of datasets, we may be able to answer such questions as how species
initially establish and what conditions must occur for them to be able to rapidly
expand their populations.
Even without specific quantifiers for rates of spread, these data can be useful to
examine the invasion time scale. Crayfish data from herbarium records and the lit-
erature for Wisconsin, USA, could be divided into three time bins: pre-invasion of
the nonnative species, postinvasion (coexistence), and extant years when native
populations had declined and the nonnative species was abundant (Olden et al.
2006). Analysis of this data revealed impacts on the crayfish community caused by
