Point Count Bird Censusing Data Subset for Paper 'EFFECTS OF LAND USE AND VEGETATION COVER ON BIRD COMMUNITIES' Walker et. al
Author(s):
- Jason Walker
- Eyal Shochat
- Madhusudan Katti
- Paige Warren
Abstract:
Animals utilize their environment across a range of scales, which is bounded by their extent, the broadest spatial area which organisms respond to their environment within their lifetime, and the spatial grain, the smallest area they respond to their environment (Kotlier and Wiens 1990). Within this range, organisms likely respond to their environment at a hierarchy of levels. Johnson (1980) recognizes four distinct levels of hierarchical habitat selection. At the very largest scale, first order selection, includes the entire area that an organism utilizes within its lifetime, and is also known as an organisms global home range or extent. In contrast, second order selection is an organisms local home range, or the area that it occupies within a unique ecosystem. This distinction is most apparent with migratory animals who utilize more than one distinct landscape for their survival (i.e. summer vs. winter feeding grounds), and much less so for organisms resident of one specific landscape for their entire life span. Third order selection is the selection of specific habitat patches within an ecosystem. For example, a Monarch butterfly would tend to select patches of milkweed within a prairie. And the lowest level, fourth order selection, involves the physical procurement of food within a selected patch, in our example, specific flowers within a milkweed patch, and is also known as grain. Realizing the importance of hierarchical habitat selection, it has become apparent that single-scale studies of animals responses to their environment may fail to adequately represent how that specific animal is responding to ecological parameter of interest, especially if they are not responding to the landscape at that scale (Holling 1992). The range of scales which an animal of interest is utilizing a landscape is important to determine prior to any further ecological investigation, as inappropriate scalar mismatch between organism and environment can lead to ambiguous or even deceptive conclusions.
To do this, we compared the correlation coefficients of bird abundances for different functional groups (e.g. foraging guilds, natives vs. exotics) with vegetation cover, as a proxy for habitat, across a range of scales (from 100m to 10km). Theoretically, a unimodal (hump-shaped) relationship should exist for the correlation coefficients across a range of scales, under the assumption that vegetation cover is an adequate estimate of bird abundance. The peak of that relationship, if statistically significant, would represent the strongest correlation between habitat and bird abundance, and thus signifies the average third order selection unit for that group. A strong peak is expected for species directly dependent on vegetation for food (herbivores), a weaker peak for omnivores, and the weakest relationship for those species indirectly dependent on vegetation (insectivores). The regional distributional patterns of the varying bird functional groups was also estimated by utilizing interpolation techniques designed for avian censuses in urban systems. Exotic species were expected to be spatially aligned to the urban ecosystem, and native species tied to the desert ecosystem. Herbivores were expected to exist in higher densities were vegetation is greatest, which typically exists within the city and agricultural fields in arid ecosystems.
The ongoing project (since October 2000) is documenting the abundance and distribution of birds in four habitats (51 sites): Urban (18) Desert (15) Riparian (11) and agricultural (7). The 40 non-riparian sites are a subset of the 200 CAP- LTER points. We are using point counts to survey birds four times a year (January, April, July and October). During each session each point is visited by three birders who count all birds seen or heard for 15 minutes. Our goal is to study how different land-use forms affect bird abundance, distribution and diversity in the greater Phoenix area in order to predict and preserve high bird species diversity as urban development is proceeding. We have now just completed 3 years of monitoring, and are also beginning to see some of the sites changing due to new urban development. The results described below are based on analyses of the first two years data.
Keywords:
Temporal Coverage:
2003-01-01 to 2003-12-31Geographic Coverage:
Geographic Description: The Phoenix Metropolitan area is located at the Northern edge of the Sonoran DesertBounding Coordinates:
Longitude:-112.743539 to -111.61843
Latitude:33.883451 to 33.208079
Contact:
Information Manager,Global Institute for Sustainability,Arizona State University,POB 875402,Tempe
caplter.data@asu.edu
Methods used in producing this dataset: Show
Data Files (4) :
Tabular: 127_birds_2003_1.csv
Description: bird observations in 2003
Column | Description | Type | Units |
---|---|---|---|
survey_date | Date of the survey |
datetime | Format: MM/DD/YYYY |
sample_id | NO Metadata Provided |
string | |
survey_id | Unique sequential numbers used to identify
surveys |
integer | |
species_id | Abbreviation of the common name of a
species |
string | |
site_id | Unique letters and numbers used to identify individual
sites. |
string | |
distance | Distance of the surveyed areas |
string | |
bird_count | Count of the birds |
integer | dimensionless |
notes | Extra observations made by the
surveyers |
ntext | |
seen | Birds seen |
bit |
Enumeration:
|
heard | Birds heard |
bit |
Enumeration:
|
direction | Direction of the bird sighting |
string | |
flying | NO Metadata Provided |
string | |
QCflag | NO Metadata Provided |
string | |
QCcomment | NO Metadata Provided |
string |
Tabular: 127_sites_1.csv
Description: site descriptions
Column | Description | Type | Units |
---|---|---|---|
site_id | Unique letters and numbers used to identify individual
sites. |
string | |
area | Area of the site |
integer | |
description | Descriptions of the sites used |
string | |
sample | Type of habbitat surveyed |
string |
Enumeration:
|
address | US street address of sites used in this
study |
string | |
city | City where the sites are located |
string | |
state | US state where the site is located |
string | |
zip | US zip code of the state |
string | |
phone | Phone number of the volunteers |
string | |
arthropod_sites | NO Metadata Provided |
string |
Tabular: 127_taxon_list_1.csv
Description: lookup table for species codes
Column | Description | Type | Units |
---|---|---|---|
species_id | Abbreviations of common name |
string | |
common_name | Common names of bird species |
string | |
asu_itis | Internal taxon ID |
integer |
Tabular: 127_guilds_1.csv
Description: feeding guilds of bird species
Column | Description | Type | Units |
---|---|---|---|
species_id | Four letter species name abbreviation as used in bird_taxon
table |
string | |
common_name | common name for bird species |
string | |
guild | feeding guild species belongs to |
string | |
origin | native or not to the northern Sonoran Desert
region |
string |