Impacts of Hurricane Sandy on the reptiles and amphibians of Fire Island

Introduction

Discussion

Target Species

Results

Methods

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

Eastern Box Turtle Northern Diamondback Terrapin

Nu

mb

er o

f in

div

idu

als

fou

nd

per

ho

ur

of

sear

chin

g

Abundance of Eastern Box Turtles and Northern Diamondback Terrapins

2002 2014 2002 2014

We recorded the abundance and distribution of all reptiles and amphibians species present by following the protocol of the previous survey (Cook et al. 2010). Our survey period went from May 2, 2014 to July 20, 2014. Following is a brief description of each survey technique:

•Visual Encounter Surveys- We used random transects to search for Eastern Box Turtles and the nests of Diamondback Terrapins. Our surveys strived to encompass all habitat types present on the island.

•Anuran Call Surveys- Evening call surveys were carried out at wetland locations to detect calling Fowler’s toads. Each survey was performed according to the North American Amphibian Monitoring Program (NAAMP). Abundance was calculated using conservative estimates for each level of the Amphibian Calling Index used in the previous survey.

Measuring and recording data on a box turtle found during a visual encounter survey.

A small turtle trap being checked in a salt marsh.

Fowler’s Toad: Anaxyrus fowleriStatus: Least Concern Habitat: Wooded areas, vernal pools, flood plains and valleys

Eastern Box Turtle: Terrapene carolinaStatus: Vulnerable/ State Special ConcernHabitat: Broadleaf deciduous forest, forest/field edges, shrubby grasslands and marsh meadows

Eastern Mud turtle: Kinosternon subrubrumStatus: State Endangered Habitat: Shallow, soft bottomed, heavily vegetated water bodies

Spotted Turtle: Clemmys guttata Status: Endangered/ State Special ConcernHabitat: Vernal pools, bogs, swamps, marshes and wet forests

Common Snapping Turtle: Chelydra serpentinaStatus: Least concernHabitat: Wide variety of freshwater habitats

Northern Diamondback Terrapin: Malaclemys terrapinStatus: Near Threatened/ State Species of Greatest Conservation Need Habitat: Semi-aquatic, brackish waters, tidal flats

As a barrier island, Fire Island protects the south shore of Long Island, New York from wind, wave and tidal impacts from major storms and hurricanes. The reptiles and amphibians, or herpetofauna, that inhabit these unique barrier island ecosystems must adapt to extreme changes in habitat in order to survive. Aside from the general destruction hurricanes inflict, they can also alter or destroy vernal pools and cause an increase in salinity in breeding wetlands in coastal areas (Schriever et al. 2009,Keefe and Carpenter 2014).

Oblique aerial photographs of the breach on Fire Island near Pelican Island before (top) and after(bottom) Hurricane Sandy (USGS). The breach is still present as of 2014, serving as a reminder of the damage that the storm caused.

From May to July 2014, we performed an inventory of reptiles and amphibians for Fire Island National Seashore. A previous inventory was conducted by the National Park Service in 2002 (Cook et al. 2010), several years prior to Hurricane Sandy in 2012. The objective of our inventory was to compare the abundance and distribution of species we found in 2014 with those documented in 2002 to examine the impacts of Hurricane Sandy on the herpetofauna of Fire Island.

Reptiles and amphibians are valuable as both prey and predators. They provide sustenance to larger predators and prey on a broad array of vertebrates and invertebrates. Due to their porous, sensitive skin, amphibians are considered indicator species which can alert us to water and air pollutants. By developing baseline data for “normal” impacts of hurricanes it will allow us to recognize abnormal changes in abundance and distribution of herpetofauna which could indicate serious problems in the ecosystem.

Both the 2002 and the 2014 survey found eight species of reptiles and amphibians native to Fire Island. We concentrated on what impacts Hurricane Sandy had on the following six species:

•Turtle Trap Survey- Large and small turtle traps were used to estimate the abundance and diversity of aquatic turtle species. The number and size of the traps was determined by the size of the wetland. Traps were baited with sardines and checked every 24 hours, usually for three nights. All turtles were marked with a unique notch code.

•Fowler’s Toads almost tripled in abundance from 2002 to 2014

•Calling activity was recorded at two additional ponds in 2014

Charles Calafiore¹, Gabrielle Woodford¹, Anna O’Malley², Nancy Karraker³¹Coastal Fellow, ²Coastal Fellowship Mentor, ³Department of Natural Resources Science , University of Rhode Island

Aquatic TurtlesThe increase in abundance of snapping turtles could be contributed to a loss of suitable

habitat due to an increase in wetland salinity following Hurricane Sandy. This may have prompted many snapping turtles to move into the largest permanent pond in the area, Kismet Pond, where we had the highest trapping success thereby increasing apparent abundance.

Although mud turtle abundance did not change between surveys, we found that distribution shifted. Occupied wetlands in 2002 were dried up or had signs of disturbance from the hurricane. We did not recover any previously marked turtles but we speculate the changes in habitat caused them to relocate.

Eastern Box TurtlesContraction of suitable habitat following Hurricane Sandy potentially contributed to a greater

detection rate and an apparent increase in eastern box turtle abundance. In addition, drought in 2002 may have led to an increased period of inactivity during the previous survey as box turtles are most active during rainfall. The abundance of box turtles from the previous survey is likely underestimated because a large number of turtles we encountered were aged over 15 years which predates the survey of 2002.

Fowler’s ToadsNumbers of active fowler’s toad breeding ponds increased from 2002 to 2014, potentially

due to drought in 2002 drying up ponds and making them unsuitable for breeding in that year. Alternatively, Hurricane Sandy’s changes to the topography and hydrology of the island’s wetlands could be responsible for the change.

Increase in toad abundance is likely independent of storm effects and changes in breeding ponds. Fowler’s toads require three years to become sexually mature, meaning that many toads born after Hurricane Sandy are not yet calling and cannot contribute to the increase. Additionally, anecdotal reports suggest that Fowler’s toad populations may have experienced a bottleneck in recent decades and the increase in abundance recorded may indicate a continued recovery from this bottleneck.

ConclusionWe did not detect significant decreases in abundance in any of the target species. Although

Hurricane Sandy caused major damage to the island and may have altered the distribution of species, we found that the reptiles and amphibians were fairly resistant to the impacts of the storm.

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

Spotted Turtle Snapping Turtle Eastern Mud Turtle

Nu

mb

er o

f in

div

idu

als

cap

ture

d p

er t

rap

nig

ht

Abundance of Aquatic Turtles

0

1

2

3

4

5

6

Spotted Turtle Snapping Turtle Eastern Mud Turtle

Nu

mb

er o

f w

etla

nd

s w

her

e p

rese

nt

Number of Wetlands inhabited by Aquatic Turtles

2014 2014 2014

2014 2014 20142002 2002

20022002

2003

2003

Results Continued

•There was a large increase in snapping turtles from 2002 to 2014

•There was a slight decrease in abundance of spotted turtles and eastern mud turtles from 2002 to 2014

•Mud turtles were trapped in only one wetland in 2014 compared to 3 in 2002

•Eastern box turtle abundance doubled from 2002 to 2014

•There was not a significant change in northern diamondback terrapin abundance

Acknowledgments: We would like to thank our superb advising professor, Dr. Nancy Karraker, the National Park Service, the University of Rhode Island’s Coastal Fellow Program and our mentor, Anna O’Malley for her courageous leadership.

References: Cook, R. P., D. K. Brotherton, and J. L. Behler. 2010. Inventory of amphibians and reptiles a Fire Island National Seashore. Natural Resource Technical Report NPS/NCBN/NRTR 2010/378. National Park Service, Fort Collins, Colorado.Keefe, I. and C. Carpenter. 2014. Vernal pool status following two major disturbances (100 year flood and Hurricane Irene). Center for Earth and Environmental Science Student Posters. Book 16.Schriever, T.A., J. Ramspott, B.I. Crother, C.L. Fonteno Jr. Effects of hurricanes Ivan, Katrina, and Rita on a southeastern Louisiana herpetofauna. Wetlands 2009, 29, 112-122.

*All photographs taken by Coastal Fellows except where otherwise stated. Back ground photograph by Andrew C. Mace.

Abundance was corrected for the number of traps nights in each survey year.

Abundance is corrected for the number of search hours performed in each survey.

2002 2014

0

0.5

1

1.5

2

2.5

3

3.5

4

Nu

mb

er o

f Fo

wle

r’s

toad

sp

er c

all s

urv

ey

Abundance of Fowler’s Toad

2002 2014

0

1

2

3

4

5

6

7

8

Nu

mb

er o

f P

on

ds

wit

h c

all a

ctiv

ity

Number of Ponds with Calling Activity

Abundance was corrected for the number of call surveys performed during each survey.

A male fowler’s toad calling to attract a mate (Larry Lyons).