habitat fragmentation and breeding birds at nasa goddard space flight center, greenbelt, maryland...
TRANSCRIPT
Habitat Fragmentation and Breeding Birds at NASA Goddard Space Flight
Center, Greenbelt, Maryland
Dr. Lowell Adams Natural Resources Management Program
University of Maryland College Park, MD 20742
Urban development fragments wildlife habitat into smaller, more isolated units.
So what?
Habitat fragmentation results in fewer numbers of species.(Loss of biodiversity)
Why?
Island Biogeography Theory
A local example
NASA Goddard Space Flight Center
Greenbelt, Maryland
Procedures
Birds Point counts and transect counts for breeding
birds (Ralph et al. 1995, Bibby et al. 2000)
ProceduresBirds 5-min point counts conducted in large
woodlots within a 50-m radius of each point Transect counts conducted through center of
small woodlots (5 min/100-m transect) 7-10 surveys conducted at each site during
June 2002 Counts conducted from sunrise to 9 am
during fair weather conditions All species seen or heard and number of
individuals/species recorded Individual birds recorded only once/survey
Numbers of Species in Relation to Woodlot Size
y = 4.705Ln(x) + 15.858
R2 = 0.7923
0
5
10
15
20
25
30
35
40
45
0 5 10 15 20 25 30 35
Woodlot Size (ha)
Nu
mb
er o
f S
pec
ies
Log Species in Relation to Log Woodlot Size
y = 0.2551x + 1.1623
R2 = 0.8207
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
-1 -0.5 0 0.5 1 1.5 2
Log Woodlot Size (ha)
Lo
g N
um
ber
of
Sp
ecie
s
Number of species of breeding birds in forest fragments__________________________________________________
Forest fragment size ______________________________________
Large Medium Small (x = 15.82 ha) (x = 2.83 ha) (x = 0.36 ha)___________________________________________________________________Median number of species 19 20.5 11
Range 14-25 14-24 7-14
n 19 10 11
H’ = 23.04, df = 2, P < 0.001 _____________________________________________________________________
Area-sensitive Forest Birds (Darr et al. 1998)
Forest fragment size Large Medium SmallRed-shouldered hawk xYellow-billed cuckoo x xRed-bellied woodpecker x x xHairy woodpecker x x xPileated woodpecker xEastern wood-pewee x x xAcadian flycatcher x xWhite-breasted nuthatch x x xBlue-gray gnatcatcher x x xWood thrush x xYellow-throated vireo x x Red-eyed vireo x x Northern parula x xBlack-and-white warbler xWorm-eating warbler xOvenbird x xLouisiana waterthrush Not recordedKentucky warbler Not recordedHooded warbler Not recordedSummer tanager xScarlet tanager x x
Area-sensitive Forest Birds
(Species recorded only in large fragments)
Red-shouldered hawk (5 recorded)
Pileated woodpecker (2 recorded)
Black-and-white warbler (1 recorded)
Worm-eating warbler (5 recorded)
Summer tanager (1 recorded)
Area-sensitive Forest Birds
29 wood thrushes recorded in large fragments (1 in medium fragments)
55 ovenbirds recorded in large fragments (3 in medium fragments)
31 scarlet tanagers recorded in large fragments (3 in medium fragments)
Distribution of “suburban residential” birds at NASA Goddard Space Flight Center, Greenbelt, Maryland, summer 2002.________________________________________________ Forest fragment size Suburban residential birds ____________________ (Aldrich and Coffin 1980) Large Medium Small________________________________________________Blue jay x x x American robin x x xGray catbird x x xNorthern mockingbird x x xEuropean starling x xNorthern cardinal x x xSong sparrow x xHouse sparrow x x x________________________________________________
Suburban Residential Birds
Most Abundant in Small Fragments
Gray catbird (6 of 36 in large fragments)
House sparrow (1 of 23 in large fragments)
Suburban Residential Birds
Most Abundant in Medium Fragments
Northern mockingbird (4 of 39 in large fragments)
All European starlings (40) in medium and small fragments on more developed west campus.
Most Abundant and Widespread Species
Tufted titmouse
Carolina Chickadee
Carolina wren
Combined, made up 28.5%, 37.0%, and 33.7% of the bird community in large, medium, and small fragments.
Procedures
Owls Tape playback recordings for
screech, barred, and great-horned owls
Great horned owl (0.14) Barred owl (0.29)
Eastern screech-owl (0.14) Barred owl (0.71)
Summary
1. Seventy species recorded in breeding bird survey.
2. Small forest fragments contained about half the number of species in large and medium- sized fragments.
3. Small fragments do not provide habitat for “area sensitive” species in need of conservation.
Summary
4. Any additional fragmentation of forests at Goddard will further impact forest bird species most in need of conservation.
5. Species most likely to be lost with further fragmentation are summer tanager, black- and-white warbler, and worm-eating warbler.
Summary
6. Three owl species were recorded (eastern screech-owl, barred owl, and great horned owl). All were located in large forest tracts.
Loss or modification of the large forested fragments would be detrimental to these species.