Jr. Miller et al., CHANGES IN THE LANDSCAPE STRUCTURE OF A SOUTHEASTERN WYOMING RIPARIANZONE FOLLOWING SHIFTS IN STREAM DYNAMICS, Biological Conservation, 72(3), 1995, pp. 371-379
Throughout western North America, flood regimes have been altered as a
result of large-scale water impoundments and diversions, yet the effe
cts on riparian landscape structure have not been quantified. Using ae
rial photographs and a GIS, we examined changes in the Rawhide Wildlif
e Management Area in southeastern Wyoming between 1937 and 1990 after
shifts in the frequency and intensity of flooding of the North Platte
River. The river declined in wetted area by 75% between 1937 and 1990.
Also, the areal proportion occupied by cottonwood (Populus spp.) stan
ds with <30% canopy closure increased while stands with >70% canopy cl
osure decreased during this period, indicating a shift from young, den
se stands to older, more open stands. Some traditional measures of lan
dscape structure (i.e. richness, diversity, dominance, average patch p
erimeter length, average patch shape), however, appeared insensitive t
o these changes. Finally, the proportion of the landscape that changed
land types declined with increasing distance from the river. We expec
t further modification of the landscape structure, associated with con
tinued declines in cottonwood recruitment and increases in cottonwood
mortality.