Forest Birds and Forest Fragmentation:

Fieldwork at the computer

for non early risers…

Maria Fernandez and Brenda McComb

Some background...

Regional landscape patterns affect the composition and structure of bird communities, especially in human-dominated environments.

We need to understand better the scales/aspects of landscape pattern that are ecologically relevant for the birds, in order to define adequate land-use policies in rural environments.

To ensure the conservation of bird communities...

Population and community processes in the avifauna operate at a range of scales.

Which factors determine community structure at a location?

*Nesting site and local habitat characteristics

*How much habitat in landscape, how is it arranged in space and time, and context...

*Studying this is very $$$

*Time and effort!!!!

*Impossible to manage habitat for each/all the species in a community.

*It is not enough anyway…

*Cheap: $4000 (RA)

*No field work! : lots of data out there..

*Results comparable to field work studies.

This is the focus of our study!

The challenge…

Understand the

Think: “putting the pieces

together”

isolated and combined EFFECTS

of SPATIAL AUTOCORRELATION,

LANDSCAPE STRUCTURE,

at a RANGE OF SCALES,

on FOREST BREEDING BIRD COMMUNITY STRUCTURE

in WESTERN MASSACHUSETTS

using AVAILABLE DATA…

and FOREST CONFIGURATION / COMPOSITION,

Our recipe:

*GET BIRD ABUNDANCE DATA FROM BREEDING BIRD SURVEY

*CREATE A MAP OF BIRD OBSERVATION POINTS

*PRODUCE/GET LAND COVER MAP OF THE AREA

*CALCULATE LANDSCAPE METRICS FOR EACH BIRD SITE AT DIFFERENT SCALES

*COOK IT ALL SLOWLY USING CANONICAL CORRESPONDENCE ANALYSIS (CCA) AND VARIANCE DECOMPOSITION

*COMPARE WITH OTHER FIELD INTENSE STUDIES

The execution…PROCESS BREEDING BIRD SURVEY

(BBS) DATA

*10 active routes in western Ma

*404 “point counts” with available data

*7 years of data (1996-2002)

*Total of 85 forest species, 7076 individuals.

QUANTIFY LANDSCAPE PATTERN: FRAGSTATS MOVING WINDOW:

119 Landscape metrics measured at 8 different scales= 952 potential

explanatory variables

3 Km

Ha: 7 15 23 45 87 175 350 700

DIGITIZE BBS STOPS

*From USGS paper maps.

PROCESS LAND COVER (1999)

Obtained from Resource Mapping lab

*Perform step wise selection for each variable, to choose the scale at which each

variable contributes more to the bird community:

Variables reduced from 952 to 119

LANDSCAPE/FOREST

*Create “space

variables” using x,y

coordinates of the plots

*This will control for

autocorrelation

SPACE

*Separate variables in three groups: -landscape structure

-forest composition -forest configuration *Perform forward selection and Montecarlo unrestricted permutation test to reduce inflation of explained variance due to chance:

Further reduction of variables from 119 to 36 36

DATA MATRIX FOR CCA ANALYSIS

404 sites

DEPENDENT INDEPENDENT VARIABLES

*Get rid of non forest

species

*Use “downweight

” of rare/ undersample

dspecies

BIRDS

85 bird species 8 space 13 landscape structure 17 forest structure 8 composition 8 configuration

DATA MATRIX FOR CCA ANALYSIS

404 sites

DEPENDENT INDEPENDENT VARIABLES

What is Canonical Correspondence Analysis CCA?

It is a multivariate technique that finds the environmental gradients that best explain the species abundance gradients: it organizes the species and sites along axes that are linear combinations of the environmental variables.

It is possible to partition the variation in the birds in components explained by certain groups of variables

We express how much the measured environmental gradients are related to the bird community structure in terms of the % of variation present in the bird community that is “explained” or “captured” or “modelled” or “predicted” by the environmental variables.

FOREST COMPOSITION

(PLAND)

FOREST CONFIGURATION

ALL ENVIRONMENTAL

SPACE

LANDSCAPE STRUCTURE

FOREST STRUCTURE

Removed the effect of “space” or autocorrelation

Variation due to landscape only

% VARIATION IN THE BIRD COMMUNITY EXPLAINED BY EACH

SET OF VARIABLES

3.05

18.32.2

14.7

3.6

2.4

5.5

6.8

(after Anderson & Gribble, 1998)

UNEXPLAINED VARIATION:

microhabitat/habitat

demographics

elevation

temperature

landscape factors at other scales

predatiom

competition

evolution

chance...

Landscape and forest model

Space effects removed

% bird variance explained: 18.3

Mature Forest Open/disturbed/early succ.Scarlet tanager

Ovenbird

Red-eye vireo

Wood thrust

Song sparrow

European starling

House finch

House wren

Forest configuration Forest composition

Landscape structure

OTHER FIELD STUDIES

Oregon Coast Pitch Pine-Scrub oak Western Ma

# sites 535 56 404

# species 69 45 85

# environmental v. 62 6 36

% variation

exp. by landscape 16% 12.3% 18.3%

-Most of the landscape variables important in the model were those measured at small to intermediate scales: < 175 ha

-Our study provides information comparable to other intensive field studies at a much lower cost.-The different CCA models are composed by meaningful and significant gradients, although most of the species have a low fit.

-Most of the forest configuration variables important in the model were those measured at intermediate to large scales: 87 to 700 ha, which suggests that the birds are responding to fragmentation at these scales.

PRELIMINARY CONCLUSIONS

-This is a work in progress. Further interpretation of results will provide specific land use/rural development policies to preserve bird communities in Western Massachusetts.

Thanks!

*Connecticut River Assessment Project

*USGS Patuxent Wildlife Research Center. 2005. North American Breeding Bird Survey provided bird data and BBS routes.

*Prof. Kevin McGarigal’s Landscape Ecology Lab. at Umass-Amherst provided partially processed landscape data.

*Photos: Copyright 1997, 1998, 2002, 2003 Gregory J. Scott and/or Ralph W. Scott.