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.