Point-count bird censusing: long-term monitoring of bird abundance and diversity in central Arizona-Phoenix, ongoing since 2000

project overview Over the past half-century, the greater Phoenix metropolitan area (GPMA) has been one
of the fastest growing regions in the US, experiencing rapid urban expansion in addition
to urban intensification. This backdrop provides an ideal setting to monitor biodiversity
changes in response to urbanization, and the CAP LTER has been using a standardized
point-count protocol to monitor the bird community in the GPMA and surrounding Sonoran
desert region since 2000. The bird survey locations in this CAP LTER core monitoring program include six
general site groupings: ESCA. Forty bird survey locations were selected from a subset of the CAP LTER's
Ecological Survey of Central Arizona (ESCA; formerly named Survey200) long-term
monitoring sites. ESCA sites were located using a tessellation-stratified
dual-density sampling design, and, as such, span a diversity of habitats including
urban, suburban, rural, commercial areas, parks, agricultural fields, and native
Sonoran desert. Earlier versions of this data package included data from the ESCA
project that was intended to complement the bird data. However, while positioned in
close proximity, the bird survey locations do not necessarily overlap with the 30m x
30m plot that constitutes an ESCA sampling location, and leveraging data from these
two monitoring programs should be addressed carefully. ESCA data have corresponding
survey location names, and those data are available through the CAP LTER and LTER
network data portals. At the conclusion of the 2016 spring survey, fifteen of the
ESCA-correlated sites were discontinued as the core monitoring program refocused its
efforts on desert parks and PASS neighborhoods. Among the deleted locations were all
agricultural and commercial sites, as well as sites where access had become
restrictive. North Desert Village (NDV). Additional bird survey locations were positioned in
treatment areas of the North Desert Village (NDV). This was a site of intense study
on the Arizona State University Polytechnic Campus in which the CAP LTER converted
the landscaping of small neighborhoods to reflect the dominant landscaping
preferences employed throughout the GPMA. NDV landscape types include: oasis
(NDV-O), xeric (NDV-X), mesic (NDV-M), control (NDV-C), and native (NDV-N).
Monitoring at NDV was discontinued after the spring 2016 season as research efforts
at this site came to an end. Riparian. While the forty bird survey locations that were selected to coincide
with ESCA sampling locations span a wide diversity of habitats throughout the GPMA,
because of the generally random nature of selecting those sites, they did not
reflect riparian habitats. Riparian areas are important bird habitat but constitute
a very small area of the GPMA. To address this deficiency, bird survey locations
were established specifically in twelve riparian habitats. Riparian habitat
sub-types include: (1) ephemeral-engineered (EE, n=4), (2) ephemeral-natural (EN,
n=2), (3) perennial-engineered (PE, n=3), and (4) perennial-natural (PN, n=3). This
research was successfully concluded and these sites were discontinued after the
spring 2016 season. Salt River. Seven study sites along the Salt River as it runs through the GPMA
that were selected as part of a related study (Salt River Biodiversity Project
(SRBP)) were ultimately included in the CAP LTER's core bird monitoring programs.
These sites reflect continued monitoring of riparian habitat. Desert Fertilization. Beginning with the 2016-2017 winter survey, six sites at
desert parks were added to core monitoring to coincide with the CAP LTER Desert
Fertilization (DesFert) experiment sites. PASS. Beginning with the 2016-2017 winter survey, what used to be a separate
bird-monitoring effort (monitoring in Phoenix Area Social Survey (PASS)
neighborhoods) was incorporated into this core bird-monitoring program. Eight points
were carried over from prior PASS monitoring, and 28 new points established,
resulting in three bird monitoring locations in each of the twelve PASS
neighborhoods. Visiting these locations each year, versus only in years surrounding
the PASS survey as done previously, provides more data on bird populations found in
the neighborhoods of the CAP LTER study area. method overview In a given season, each bird survey location is visited independently by three
birders who count all birds seen or heard within a 15-minute window. The frequency of
surveys has varied through the life of the project. The first year of the project (2000)
was generally a pilot year in which each site was visited approximately twice by a varying
number of birders. The monitoring became more formalized beginning in 2001, and each site
was visited in each of four seasons by three birders. The frequency of visits was reduced
to three seasons in 2005, and to two season (spring, winter) beginning in 2006.