the effect of residential properties on breeding bird diversity in urban forest patches
DESCRIPTION
The Effect of Residential Properties on Breeding Bird Diversity in Urban Forest Patches. Chrissa Carlson 1 , Mary Cadenasso 2 , Gary Barrett 1 Institute of Ecology, University of Georgia Department of Plant Sciences, University of California, Davis. Submitted to Ecological Applications. - PowerPoint PPT PresentationTRANSCRIPT
The Effect of Residential Properties on Breeding Bird
Diversity in UrbanForest Patches
Chrissa Carlson1, Mary Cadenasso2, Gary Barrett1
1. Institute of Ecology, University of Georgia2. Department of Plant Sciences, University of California, Davis
Submitted to Ecological Applications
Urban Habitats:
•Not all are created equal How is
biodiversity is impacted by surrounding
urban development?
•Residential areas: top-down vs. bottom-up management (Melles 2005)
•Interaction between landscape elements under different management regimes
Urban Habitats:
Birds and urban biodiversity
• Quality of life (Clergeau et al. 2001)
• Biological poverty (Turner et al. 2004)
• Respond to environmental variables at multiple scales (Hostetler 2001)
• Conservation of metapopulations (Fernandez-Juricic 2004)
Major research question
• Can homeowners modify avian diversity in forest fragments from the outside-in?
• Is there a relationship between breeding bird community structure within forest habitat fragments and the resources located in the surrounding residential matrix, managed by humans at the scale of the individual land parcel?– Resources=tree and other vegetation cover,
bird feeders, baths, etc.
Major research question
Birds in urban forest fragments:
• Island biogeography theory (Robbins et al. 1989) but…– Patches of equal area often differ in species
richness (Dawson et al. 1993)– Isolation not as important as in agricultural
landscapes (Watson et al. 2005)
• Landscape context matters (Bennett et al. 2004, Park and Lee 2000, Nilon and Pais 1997, Andren 1994)
• Land-use is a poor predictor of bird occurrence (Hostetler and Knowles-Yanez 2003)
Total species richness is best explained by patch-level features (area, vegetation structure), but additional variation may be explained by:•Neighborhood age (+)•Variation in the distribution of landcover types in the surrounding neighborhood
Hypotheses:
Methods: Site Selection• 2-10 ha forest patches in Gwynns Falls Watershed• Surrounding landuse primarily residential• National Landcover Dataset (NLCD) 2000 and EMERGE 2004 aerial imageryn=15
Methods: Bird Surveys
• Territory mapping method
A
A
• Territory mapping method– Each site visited six times– Clusters of detections used to estimate
relative density of breeding territories
Methods: Bird Surveys
Patch 12: Northern Cardinal
B
C
D
Methods: Forest Patch Characterization
• Patch area• Modified UFORE surveys on 5 m radius
plots centered at random points– tree species richness– tree density– max DBH– foliage height diversity– stem size diversity
• Principle Components Analysis performed on vegetation structure variables to capture variation in forest structure among sites
Methods: Neighborhood Characterization
• HERCULES classification (Cadenasso et al. in press) applied to surrounding neighborhoods within 100 m buffer
Methods: Neighborhood Characterization
Bldg type: 1Bldg cover: 3CV cover: 1FV cover: 3Pavement cover: 2Bare soil cover: 0
Bldg type: 2Bldg cover: 3CV cover: 1FV cover: 3Pavement cover: 2Bare soil cover: 0
Bldg type: 1Bldg cover: 3CV cover: 1FV cover: 3Pavement cover: 2Bare soil cover: 0
Bldg type: 0Bldg cover: 0CV cover: 0FV cover: 2Pavement cover: 1Bare soil cover: 1
Bldg type: 2Bldg cover: 3CV cover: 1FV cover: 1Pavement cover: 2Bare soil cover: 0
Bldg type: 1Bldg cover: 3CV cover: 1FV cover: 2Pavement cover: 2Bare soil cover: 0
Methods: Neighborhood Characterization
Bldg type: 1Bldg cover: 3CV cover: 1FV cover: 3Pavement cover: 2Bare soil cover: 0
Bldg type: 2Bldg cover: 3CV cover: 1FV cover: 3Pavement cover: 2Bare soil cover: 0
Bldg type: 1Bldg cover: 3CV cover: 1FV cover: 3Pavement cover: 2Bare soil cover: 0
Bldg type: 0Bldg cover: 0CV cover: 0FV cover: 2Pavement cover: 1Bare soil cover: 1
Bldg type: 2Bldg cover: 3CV cover: 1FV cover: 1Pavement cover: 2Bare soil cover: 0
Bldg type: 1Bldg cover: 3CV cover: 1FV cover: 2Pavement cover: 2Bare soil cover: 0
• Area-weighted mean calculated for each cover variable in each buffer
• PCA performed on area-weighted means to capture variation in distribution of landcovers
Methods: Neighborhood Age• Used HERCULES classification to
calculate area-weighted median neighborhood age
Methods: Data Analysis• Information-Theoretic Model
Selection using Akaike’s Information Criterion
• Linear regression models
Multiple working hypotheses:
Total Species Richness (TSR)
– TSR=ßo+ß1(Area)+ß2(PCAveg)+ß3(Age)
– TSR=ßo+ß1(Area)+ß2(PCAveg)+ß3(Age)-ß4(Age2)
– TSR=ßo+ß1(Area)+ß2(PCAveg)+ß3(PCAHERC1)
– TSR=ßo+ß1(Area)+ß2(PCAveg)+ß3(PCAHERC1)+ ß4(PCAHERC2)
– TSR=ßo+ß1(Area)+ß2(Age)
– TSR=ßo+ß1(Area)+ß2(Age)-ß3(Age2)
– TSR=ßo+ß1(Area)+ß2(PCAHERC1)
– TSR=ßo+ß1(Area)+ß2(PCAHERC1)+ß3(PCAHERC2)
– TSR=ßo+ß1(Area)+ß2(PCAveg)
– TSR=ßo+ß1(Area)
Total species richness is best explained by patch-level features (area, vegetation structure), but additional variation may be explained by:•Neighborhood age (+)•Variation in the distribution of landcover types in the surrounding neighborhood
Results: Bird Species Detected
Results: Neighborhood Characterization
-3
-2
-1
0
1
2
3
-3 -2 -1 0 1 2 3
PCAHERC1
PCAHERC2
Results: Neighborhood Characterization
Plenty o’ pavement
Tons o’ trees
Bunch o’ bare soil
Gobs o’ grass
Results: Neighborhood Characterization
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Site number
Area-weighted median age (years)
6.46 - 60.02 years
32.49 [mean] ± 14.73 [S.D.]
TSR=ßo+ß1(Area)-ß2(PCAHERC1)0.47
TSR VI
TSR VII
Results: Model Selection
TSR VIII
TSR V
TSR IV
TSR III
TSR II
TSR I
0.0366.56
61.11
0.1363.60
0.0266.97
0.0168.02
0.1263.76
0.0267.90
0.0169.45
ωiAICcModel
TSR IX
0.1164.08
TSR X 0.0864.62
TSR=ßo+ß1(Area)+ß2(PCAveg)-ß3(PCAHERC1)
TSR=ßo+ß1(Area)+ß2(Age)-ß3(Age2)
TSR=ßo+ß1(Area)-ß2(PCAHERC1)
TSR VI
Results: Model Selection
TSR VIII
TSR V
TSR IV
TSR III
TSR II
TSR I
0.03
0.13
0.02
0.01
0.12
0.02
0.01ωiModel
TSR IX
0.11
TSR X 0.08
R2=0.69
R2=0.69
R2=0.68
66.56
63.60
66.97
68.02
63.76
67.90
69.45
AICc
64.08
64.62
Conclusions•Breaking news: Forest birds like trees
•The real kicker: they like them in their habitat, but also surrounding it. Evidence from the analysis…
•PCAHERC1 (negative) appeared in two of three best models, this axis represented the tendency for tree cover in the neighborhood to decrease as pavement increases
•The quadratic transformation of neighborhood age (AGE-AGE2) appeared in the second best species richness model; neighborhood canopy cover has an inverse parabolic relationship with neighborhood age (Grove et al. 2006)C
oars
e ve
g co
ver
Neighborhood Age
R2=0.60
~40 years
Conclusions•Neighborhood age alone did not appear in any of the top models; time since disturbance does not allow more species to colonize
•The structure of the forest itself explained less variation in breeding bird diversity than the structure of the neighborhood surrounding the forest
•Diverse household land-management practices collectively shape urban landscapes•Relationships were observed at very narrow buffer width individual landowners can impact habitats from the outside-in•Neighborhoods can be managed as a buffers to forest habitat (Watson et al. 2005)
Conclusions
• Biodiversity can be used as a tool to inform land management practices that effect multiple environmental issues
• Confronting the culture of status associated with big green lawns is a challenge for many aspects of conservation
• Emphasize aesthetic/ecological value of a complex yard habitat, particularly adjacent to forest
Conservation value?
Further research
• Different buffer widths
• Change across years
• Habitat quality: productivity/survivorship
• Test models in different landscapes
Acknowledgements• Graduate Committee: Gary Barrett,
Roarke Donnelly, Robert Cooper
• BES: Paige Warren, Charlie Nilon, Morgan Grove, Jarlath O’Neil-Dunne, Mike McGuire, Kirsten Schwartz
• Field Assistance: Andy Flies
• NSF Graduate Research Fellowship
Questions?