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Secretive Marshbird Occurrence and Abundance in Urban
Salt Marshes of New York City, NY
Final Report to the Edna Bailey Sussman Foundation
by
Alison Kocek, State University of New York College of Environmental Science and
Forestry
INTRODUCTION
The northeast Atlantic Coast of the United States has the world’s largest expanse
of tidal salt marsh (Greenberg et al. 2006) which provides critical habitat for fish and
wildlife, sediment and nutrient cycling services, and buffering of upland areas from
storms (Odum 1969, Daiber 1986, Brown et al. 2002, Koch and Gobler 2009). However,
as urbanization has become a prevailing landscape-altering human activity along our
nation’s coast, tidal salt marshes have become imperiled ecosystems that are disappearing
at an alarming rate (Dahl 1990; Noss et al. 1995; Tiner 1984). This issue is compounded
as global climate change induced sea level rise engulfs coastal fringes that contain
remnant salt marshes (Bayard and Elphick 2011).
Tidal salt marshes in New York are found primarily along the coast of Long
Island and in the lower Hudson River. Due to centuries of human development, much of
the original coastal marshland has been degraded or converted into anthropogenic
structures, especially in the New York City area. Tidal marsh obligate birds, those that
can only nest in tidal marshes, are a good indicator of the health of these marsh systems.
The objective of this study is to calculate indices of secretive marshbird occurrence and
diversity in marshes throughout New York City and to detail these relationships between
secretive marshbird occurrence and diversity throughout NYC and marsh-border
urbanization as a function of landscape-level characteristics.
METHODS
Study Area
Data collection took place throughout the New York City area and western
Nassau County on Long Island, NY. These sites included several restored salt marshes
owned by New York City Parks in Brooklyn, Queens, Staten Island, and The Bronx.
Natural and restored marshes in Jamaica Bay within the Gateway National Recreation
Area and natural salt marshes in Oceanside, NY managed by the Town of Hempstead
(Figure 1, Table 1).
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Figure 1. Map of 2014 study sites for the SUNY secretive marsh bird survey. Sparrow icons next to site names indicate that nesting
sparrows were known to occur.
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Table 1. Study sites and their abbreviations.
Site
Site
Abbreviation
Site
Sawmill Creek NE
SAW1
Rockaway Community Park
Sawmill Creek N-central
SAW2
Idlewild
Sawmill Creek NW
SAW3
Alley Pond N
Sawmill Creek SW
SAW4
Alley Pond S
Sawmill Creek SE
SAW5
Pugsley Creek
Marine Park
MAP
Pelham Bay Park S
Four Sparrow Marsh
FSM
Pelham Bay Park NW
West Pond
WEP
Pelham Bay Park NE
Big Egg Marsh
BEM
Marine Nature Study Area
JoCo Marsh E
JOC1
Lido Beach Passive Nature Area
JoCo Marsh W
JOC2
Site
Abbreviation
ROC
ID
APP1
APP2
PUG
PEL1
PEL2
PEL3
OMN
LIP
Broadcast Call Surveys
A combination of passive and broadcast survey techniques designed by the
Standardized North American Marsh Bird Monitoring Protocol (Conway and Droege
2006; Conway and Nadeau 2006) were used to detect the suite of the salt marsh bird
community. Call types used during the survey included: black rail (Laterallus
jamaicensis), least bittern (Ixobrychus exilis), sora (Porzana carolina), Virginia rail
(Rallus limicola), clapper rail (Rallus longirostris), American bittern (Botaurus
lentiginosus), and common moorhen (Gallinula chloropus). The broadcast itself included
an initial 5 minutes of silence followed by the various call types of each species played
intermittently throughout a 1 minute time period for each species, totaling in a 13 minute
survey window.
Priority species for this survey included all of the species mentioned above whose
calls were broadcasted. Secondary species of importance included tidal marsh sparrows
(saltmarsh sparrow (Ammodramus caudacutus), Nelson’s sparrow (Ammodramus
nelsoni) and seaside sparrow (Ammodramus maritimus)), willet (Tringa semipalmata)
and American black duck (Anas rubripes). All avian species mentioned above as well as
others associated with marshes or observed within the marsh were recorded when either
observed by sight or by call. The distance band from the observer in which each
individual bird occurred (0-50m, 50-100m and >100m) was also recorded and each
individual was only counted once throughout the entire survey, even if its location
changed.
As per the regional salt marsh bird study, three call-broadcast surveys were
conducted at each sampling point (once in mid-late May, mid-late June, and mid-late
July). Surveys were conducted in the mornings during the breeding season and began 30
min prior to sunrise and completed within three hours after sunrise (Conway 2008).
Vegetation Survey
25-70 points were randomly selected within each study marsh dependent on the
total area of the marsh. The vegetation structure immediately surrounding the point (1m2)
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was surveyed using a point square. Percent cover by all vegetation species, water, bare
ground and wrack were recorded as well as the heights of the vegetation at the centers of
each of the sides of the frame and the center point of the frame.
Analysis
Data analysis is being carried out using a variety of statistical tools. Vegetation
analysis was performed using Multi Response Permutation Procedure (MRPP) of withinversus among-group dissimilarities in R. The percent cover of all vegetation species
along with bare ground, water and wrack were used in this analysis. Marsh complexes
within 500m of one another were considered 1 site even if this complex contains multiple
broadcast survey points (i.e. SAW1-5, PEL 1-3). Thus only 12 sites were considered for
this analysis as 8 points were lost due to combination into marsh complexes and
Rockaway Community Park was not included in this vegetation study due to its overall
extremely small marsh area.
Species occurrence data will be added to a region wide database for occupancy
estimates to be more accurately predicted using Bayesian statistics in ArcGIS. Species
abundance in relation to landscape level characteristics, including percent urban border
(which will be obtained using ArcGIS and the 2006 National Land-Cover Database), will
be performed using negative binomial regression in R.
RESULTS
Species Occurrence
A total of 71 species were detected throughout 21 sites sampled, however no more
than 25 species were observed during any one survey (Figure 2). There does not appear to
be any regional or time related trends to species abundance in NYC however further
analysis is required to confirm this.
The number of individuals observed at each site during each survey also did not
appear to have a trend related to time of season (Figure 3). However, regionally, sites in
Staten Island, Brooklyn and Queens appear to have a similar abundance of individuals,
while Bronx and SW Nassau County sites appear to have an overall higher abundance of
individuals. Additional analysis is required to confirm this trend.
Preliminary results of mean abundance of primary and secondary priority species
is provided in Figure 4. Of the primary species, only clapper rail were detected while 4 of
5 secondary species (saltmarsh sparrow, seaside sparrow, willet and American black
duck) were observed. Clapper rail, willet and saltmarsh sparrow were most common
(each having been detected at 9 locations), while American black ducks were less
prevalent (detected at 6 sites) and seaside sparrows were fairly rarely observed (detected
at 2 sites).
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Figure 2. Number of avian species detected at 21 sites in New York City and SW Nassau County during three survey time periods
(May, June and July) in 2014. The mean of these 3 surveys is also provided.
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Figure 3. Number of individuals detected at 21 sites in New York City and SW Nassau County during three survey time periods (May,
June and July) in 2014. The mean of these three surveys is also provided.
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Figure 4. Mean individuals of primary (clapper rail) and secondary (saltmarsh sparrow, seaside sparrow, willet and black duck)
priority species detected at 21 sites in New York City and SW Nassau County in 2014. Counts were averaged over three survey time
periods (May, June and July 2014).
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Vegetation
Vegetation data is under continued analysis. The most common species found at the 12
study sites include smooth cordgrass (Spartina alterniflora), saltmeadow cordgrass
(Spartina patens), seashore saltgrass (Distichlis spicata), bigleaf marsh-elder (Iva
frutescens), common reed (Phragmites australis, an invasive species), blackgrass (Juncus
gerardii), and glasswort (Salcornia sp.). The results for the comparisons of the most
common cover types (S. alterniflora, S. patens, D. spicata, and bare ground) are found in
Figure 5. These cover types represent >90% of the total marsh cover found at each site
except Big Egg Marsh which the remaining total is composed of mainly J. gerardii. The
results indicate that many sites have a very different cover make-up and this make-up
often varies even among region, except in SW Nassau County which has natural,
unrestored sites. Continued analysis for species specific vegetation relationships is
ongoing.
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Figure 5. Multivariate median proportion foliar ground cover of random vegetation points at demographic and control sites, 2014.
Proportion cover by water, wrack, I. frutescens, P. australis, J. gerardii, Salicornia sp. and other species also used in analysis but not
included. S. alterniflora, S. patens, D. spicata, bare ground comprise >90% of foliar ground cover at all sites except BEM. Foliar
ground cover not represented at BEM comprised mainly of J. gerardii (MRPP, Pearson Type III Statistic: -31.10, P < 0.001,
Bonferroni Correction alpha level = 6.41E-4).
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FUTURE WORK
Broadcast call survey data and vegetation data has been added to a regional
database and regional occupancy and density data for each of the primary and secondary
species are ongoing using a Bayesian framework. Relationships between species
occurrence and density will be examined in relation to many landscape level variables
including vegetation make-up, weather variables, tide heights, percent urban border, total
marsh area, marsh perimeter, percent high marsh, nearby road density, open water,
latitude, geomorphic setting, and other covariates. Trends for New York will be an
important addition to this dataset as well as important standalone data due to the extreme
urbanization of the area and fragmentation of existing marshes.
Continued broadcast call survey and vegetation data collection should occur in
order to gain an understanding of species continued occupancy, seasonal trends, and
marsh level changes. Much restoration is ongoing in NYC, especially post-Hurricane
Sandy. Examining these marshes pre- and post-restoration will provide a baseline for
how various restoration methods succeed or fail at creating marsh habitat preferred by the
secretive marsh bird community.
ACKNOWLEDGEMENTS
This work would not have been possible without the Edna Bailey Sussman
Foundation for this valuable funding, the New York City Parks and Recreation
Department for providing housing and allowing me to work in Parks marshes, as well as
the Gateway National Recreation Area, and the Town of Hempstead for allowing access
to their marshes. The Foundation will be recognized in all presentations and publications
that result from this research.
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LITERATURE CITED
Bayard, T. S., and C. S. Elphick. 2011. Planning for sea-level rise: quantifying patterns of
Saltmarsh Sparrow (Ammodramus caudacutus) nest flooding under current sealevel conditions. The Auk, 128(2), 393-403.
Brown, S. C., B. A. Harrington, K. C. Parsons, and E. P. Mallory. 2002. Waterbird use of
northern Atlantic wetlands protected under the North American wetlands
conservation act. Waterbirds, 25: 106-114.
Conway, C.J., and C.P. Nadeau. 2006. Development and field testing of survey methods
for a continental marsh bird monitoring program in North America. Wildlife research
report #2005-11. USGS Arizona Cooperative Fish and Wildlife Unit, Tucson,
Arizona.
Conway, C.J., and S. Droege. 2006. A unified strategy for monitoring changes in
abundance of birds associated with North American tidal marshes. Studies in Avian
Biology 282-297.
Conway, C.J. 2008. Standardized North American marsh bird monitoring protocols.
Tucson, AZ, USA.
Dahl, T. E. 1990. Wetland losses in the United States: 1780s to 1980s. U.S. Department
of the Interior, Fish and Wildlife Service, Washington, DC, USA.
Daiber, F.C. 1986. Conservation of tidal marshes. New York: Van Norstrand Reinhold.
Greenberg, R., J. E. Maldonado, S. Droege, and M. V. McDonald. (2006). Tidal marshes:
a global perspective on the evolution and conservation of their terrestrial
vertebrates. BioScience, 56(8), 675-685.
Koch, F., and C. J. Gobler. 2009. The effects of tidal export from salt marsh ditches on
estuarine water quality and plankton communities. Estuaries and Coasts, 32: 261275.
Noss, R. F., LaRoe, E. T., and Scott, J. M., (1995). Endangered ecosystems of the United
States: A preliminary assessment of loss and degradation. US National Biological
Service.
Odum, E. P. 1969. Strategy of ecosystem development. Science, 164: 262-270.
Tiner, R. W. 1984. Wetlands of the United States: current status and recent trends. U.S.
Fish and Wildlife Service, National Wetlands Inventory, Washington, DC, USA.