New Research on Sage-Grouse Movements in WY
Interseasonal movements of
greater sage-grouse, migratory behavior, and an assessment of the core
regions concept in Wyoming
Abstract: Animals can
require different habitat types throughout their annual cycles. When
considering habitat prioritization, we need to explicitly consider
habitat requirements throughout the annual cycle, particularly for
species of conservation concern. Understanding annual habitat
requirements begins with quantifying how far individuals move across
landscapes between key life stages to access required habitats. We
quantified individual interseasonal movements for greater sage-grouse (Centrocercus urophasianus;
hereafter sage-grouse) using radio-telemetry spanning the majority of
the species distribution in Wyoming. Sage-grouse are currently a
candidate for listing under the United States Endangered Species Act and
Wyoming is predicted to remain a stronghold for the species.
Sage-grouse use distinct seasonal habitats throughout their annual cycle
for breeding, brood rearing, and wintering. Average movement distances
in Wyoming from nest sites to summer-late brood-rearing locations were
8.1 km (SE = 0.3 km; n = 828 individuals) and the average subsequent distances moved from summer sites to winter locations were 17.3 km (SE = 0.5 km; n = 607 individuals). Average nest-to-winter movements were 14.4 km (SE = 0.6 km; n
= 434 individuals). We documented remarkable variation in the extent of
movement distances both within and among sites across Wyoming, with some
individuals remaining year-round in the same vicinity and others moving
over 50 km between life stages. Our results suggest defining any of our
populations as migratory or non-migratory is inappropriate as
individual strategies vary widely. We compared movement distances of
birds marked using Global Positioning System (GPS) and very high
frequency (VHF) radio marking techniques and found no evidence that the
heavier GPS radios limited movement. Furthermore, we examined the
capacity of the sage-grouse core regions concept to capture seasonal
locations. As expected, we found the core regions approach, which was
developed based on lek data, was generally better at capturing the
nesting locations than summer or winter locations. However, across
Wyoming the sage-grouse breeding core regions still contained a
relatively high percentage of summer and winter locations and seem to be
a reasonable surrogate for non-breeding habitat when no other
information exists. We suggest that conservation efforts for greater
sage-grouse implicitly incorporate seasonal habitat needs because of
high variation in the amount of overlap among breeding core regions and
non-breeding habitat. © 2012 The Wildlife Society.
Full Citation: Fedy, B. C., Aldridge, C. L., Doherty, K. E., O'Donnell, M., Beck, J.
L., Bedrosian, B., Holloran, M. J., Johnson, G. D., Kaczor, N. W.,
Kirol, C. P., Mandich, C. A., Marshall, D., McKee, G., Olson, C.,
Swanson, C. C. and Walker, B. L. (2012), Interseasonal movements of
greater sage-grouse, migratory behavior, and an assessment of the core
regions concept in Wyoming. The Journal of Wildlife Management,
76: 1062–1071. doi: 10.1002/jwmg.337
Abstract: Animals can
require different habitat types throughout their annual cycles. When
considering habitat prioritization, we need to explicitly consider
habitat requirements throughout the annual cycle, particularly for
species of conservation concern. Understanding annual habitat
requirements begins with quantifying how far individuals move across
landscapes between key life stages to access required habitats. We
quantified individual interseasonal movements for greater sage-grouse (Centrocercus urophasianus;
hereafter sage-grouse) using radio-telemetry spanning the majority of
the species distribution in Wyoming. Sage-grouse are currently a
candidate for listing under the United States Endangered Species Act and
Wyoming is predicted to remain a stronghold for the species.
Sage-grouse use distinct seasonal habitats throughout their annual cycle
for breeding, brood rearing, and wintering. Average movement distances
in Wyoming from nest sites to summer-late brood-rearing locations were
8.1 km (SE = 0.3 km; n = 828 individuals) and the average subsequent distances moved from summer sites to winter locations were 17.3 km (SE = 0.5 km; n = 607 individuals). Average nest-to-winter movements were 14.4 km (SE = 0.6 km; n
= 434 individuals). We documented remarkable variation in the extent of
movement distances both within and among sites across Wyoming, with some
individuals remaining year-round in the same vicinity and others moving
over 50 km between life stages. Our results suggest defining any of our
populations as migratory or non-migratory is inappropriate as
individual strategies vary widely. We compared movement distances of
birds marked using Global Positioning System (GPS) and very high
frequency (VHF) radio marking techniques and found no evidence that the
heavier GPS radios limited movement. Furthermore, we examined the
capacity of the sage-grouse core regions concept to capture seasonal
locations. As expected, we found the core regions approach, which was
developed based on lek data, was generally better at capturing the
nesting locations than summer or winter locations. However, across
Wyoming the sage-grouse breeding core regions still contained a
relatively high percentage of summer and winter locations and seem to be
a reasonable surrogate for non-breeding habitat when no other
information exists. We suggest that conservation efforts for greater
sage-grouse implicitly incorporate seasonal habitat needs because of
high variation in the amount of overlap among breeding core regions and
non-breeding habitat. © 2012 The Wildlife Society.
No comments:
Post a Comment