Biology Reference
In-Depth Information
Fig. 17.5
Flow diagram linking monitoring and land management objectives for exotic invasive
plants (NIS in the figure indicates nonnative invasive species; from Maxwell 2005)
the occurrence and spread of invasive plants using a community or habitat
approach.
Prather and Lass (in press) are developing a spatially explicit plant movement
model for yellow starthistle (Fig. 17.6) and sulfur cinquefoil. They combined bio-
logical information on species dispersal and population dynamics with a network
movement model that included both slope and aspect of currently occupied and
potential sites to predict the probability of occurrence of each species using the fol-
lowing equation:
P
s
ij
2
2
2
2
ln
=+ +
bb b
uu
+ +
bnbnb
+
ln(
u
+
n
),
0
1
2
3
4
2
1
−
P
s
ij
where
P
s
ij
is the proportion of YST present at the ith and jth classification levels of
aspect and slope,
u
and
v
are polar transformations of slope and aspect given by:
u
= slope
i
cos(aspect
j
),
v
= slope
i
× sin(aspect
j
), and
b
1-
b
5 are regression
coefficients.
