Dispersal of Terrapin Hatchlings at Jamaica Bay, NY

Dispersal of Terrapin Hatchlings at Jamaica Bay, NY, updated 10/28/21, 3:31 AM

categoryScience
collectionsTerrapins
visibility92

About Turtle Survival Alliance

The Turtle Survival Alliance (TSA) was formed in 2001 as an International Union for Conservation of Nature (IUCN) partnership for sustainable captive management of freshwater turtles and tortoises, and initially designated a Task Force of the IUCN Tortoise and Freshwater Turtle Specialist Group. The TSA arose in response to the rampant and unsustainable harvest of Asian turtle populations to supply Chinese markets, a situation known as the Asian Turtle Crisis.
Since forming, the TSA has become recognized as a global force for turtle conservation, capable of taking swift and decisive action on behalf of critically endangered turtles and tortoises. Although the TSA was organized in response to the Asian Turtle Crisis, the group has been expanded as our understanding of the scope of turtle and tortoise declines has become better understood. The TSA has been particularly involved in recovery efforts where a managed breeding component is part of an overall survival strategy. The TSA employs a comprehensive strategy for evaluating the most critically endangered chelonians that identifies whether a species is prioritized for a captive program or through range country efforts, or a combination of both.
In the past 13 years, TSA secured nonprofit 501(c)(3) status (2005) and has centralized its base operations in South Carolina by opening the Turtle Survival Center (2013). The Turtle Survival Center, which now has AZA certification (2018), is home to a collection of more than 700 turtles and tortoises, representing 30 of the world’s critically endangered species. The TSA has also grown internationally, with significant field projects or programs in Madagascar, Myanmar and India, and additional projects in Belize, Colombia, and throughout Asia.
Today, the TSA is an action-oriented global partnership, focusing on species that are at high risk of extinction, and working in turtle diversity hotspots around the world. Widely recognized as a global catalyst for turtle conservation based on its reputation for swift and decisive action, the TSA has made a bold commitment to zero turtle extinctions in the 21st Century. The TSA is a recognized force for turtle conservation globally. TSA’s conservation actions utilize a three-pronged approach:
1. Restoring populations in the wild where possible;
2. Securing species in captivity through assurance colonies; and
3. Building the capacity to restore, secure and conserve species within their range country.

Tag Cloud

Dispersal of Newly-Emerged
Diamond-backed Terrapin (Malaclemys
terrapin) Hatchlings at Jamaica Bay, NY
Gateway National Recreation Area
Jamaica Bay Wildlife Refuge
Rulers Bar Hassock
Nesting Ecology
TON or TIN
Terrestrial Overwintering Outside the Nest Terrestrial Overwintering Inside the Nest
Terrestrial vs. Aquatic Overwintering
Adaptations for Terrestrial
Overwintering in Northern Latitudes
Freeze tolerance
Supercooling
West facing dune face and wrack line
2009
2010
2011
2012
The facts so far
what we know what we don't know
• Hatchling DBTs
overwinter terrestrially.
- have adapted to freezing
temperatures
• At JBay most appear to
TON.
• Probably overwinter
above the high line.
- need fresh water

Is the wrack line utilized
at all as refugia? Do any
overwinter in the wrack
line?
• Where? Habitat type?
Site characteristics?
• How long?
• Where to next?
• ……and so on
Objectives
• 1) identifying characteristics of post-emergent
diamond backed terrapin hatchling
overwintering ecology
• 2) to determine whether diamond-backed
terrapins hatchlings overwintered in the high
tide wrack line, and
• 3) to describe TON microhabitats and
determine what features influence refugia
choice
Passive Integrated Transponder
• Uses a radio signal transmitted from an
electronic device (PIT Tag)
• Activated by an electromagnetic signal from a
reading device / scanner
• Identifies an object
8.5mm x 2.12mm PIT tag
Biomark Portable BP Antennae
FS2001F-ISO Reader
Limitations
• Labor intensive
- Hatchling must be within range of the
scanner
• Read range affected by :
– Antenna power
– Tag orientation
– Interference
Data Collection
2009 -2012
2009-2010
60 Hatchlings tagged from 8 locations (7 protected
nests, wrack line)
2010-2011
36 hatchlings from 9 locations (protected nests)
2011-2012
251 hatchlings from 29 locations (protected nests)
Hatchling Locating
• 347 tagged hatchlings (6 from the wrack line)
• 205 never located again
-------------
142 located at least once
81 were located in refugia until spring
3 located in 2 separate refugia
1 located in 3 separate refugia
Distance (m)of Neonate Hatchling
Movement From Natal Nest Site
0.00
5.00
10.00
15.00
20.00
25.00
30.00
number of hatchlingsdistance from nest
Hatchlings in the Wrack Line
15 individuals found in the wrack line
6 tagged and returned
9 tagged from natal nest
None of these were located in the
wrack line past mid October
Predation?
0
5
10
15
20
25
3/17
3/24
3/31
4/7
4/14
4/21
4/28
5/5
5/12
5/19
5/26
6/2
6/9
6/16
6/23
6/30
2010-2012
Hatchling Emergence from Successful
Overwintering Refugia (n=81)
Depth of Refugia – Recovered Tags
Tag #
Nest #
Date Implanted
Date Recovered
Depth
Hatchling
Remains
40531
A
9/25/2009
7/17/2010
0-3cm
N
40541
B
9/25/2009
7/22/2010
3-5cm
N
40555
A
9/25/2009
7/22/2010
3-5cm"
Y
40583
A
9/25/2009
7/22/2010
3-10cm
Y
40579
C
9/23/2009
7/22/2010
8-10cm
Y
86189
D
9/17/2011
5/19/2012
4cm
N
85854
D
9/17/2011
5/19/2012
3-4cm
N
85178
D
9/17/2011
5/19/2012
4cm
N
84441
E
9/4/2011
5/12/2012
unk
N
83529
D
9/17/2011
5/19/2012
2cm
N
82401
D
9/17/2011
5/19/2012
0cm
N
79057
F
8/29/2011
5/19/2012
2-3cm
N
Excavated in refugia (n=4)
Depth of Hatchlings in Refugia
Excavated Before Spring Emergence
Tag #
Date of First Location
Date excavated
Depth
80676
9/17/2011
5/12/2012
under leaf litter
78347
3/17/2012
3/23/2012
6cm
78347
3/17/2012
4/6/2012
~3-4cm
79217
3/17/2012
3/23/2012
3-4cm
Refugia Site Analysis
within a 25cm2 area of successful
OWN refugia
• Average % ground cover
(t(128) = 3.85 P<0.0001)
• Canopy height (t(112) = 2.63
P= 0.011706)
• % Forb cover (t(112) = 1.87
P= 0.008643)
• Average forb height (t(112) =
2.28 P < 0.0001)
• Average tree height (t(112) =
1.69 P= 0.00796)
within a 5m radius of the
successful OWN refugia
• Average % ground cover (t(100) =
0.04 P= 0.036702)
• Canopy height (t(98) = 2.81 P=
0.002271)
• Forb height (t(99) = 0.99 P <
0.0001)
• Grass height (t(99)= -1.3 P <
0.0001)
• % Bush (t(99) = 0.92 P= 0.002568)
• % Tree (t(99) = 2.51 P= 0.003917)
• Tree height (t(99) = 2.4 P=
0.019265)
Ground Cover
Percent Ground Cover Composition for Successful Overwintering Refugia vs.
Non Successful Overwintering Refugia.
0
10
20
30
40
50
60
70
80
90
100
Leaf Litter
Plant Material
Woody Debris
Wrack Line
Rock
Trash
Successful Overwintering refugia
Non Successful Overwintering Refugia
In Conclusion
• Successful refugia have a vegetative
component and a ground cover component
• Refugia depth = up to 10 cm with some
movement
• Do not overwinter in the wrack line at Jamaica
Bay
• Emerge from refugia March – May. Probably
do not stay on land.
• TON sites may be chosen to avoid desiccation
What next?
Below ground
conditions of
refugia.
Effects of ground
cover types on
subsurface
conditions.
Where do they go
after spring
emergence?
Acknowledgements
• Dr. Russell Burke and the diamond backed terrapin
research team – Hofstra University
• Biomark Inc.
• Jamaica Bay Institute
• American Museum of Natural History/ Lerner Gray
Fund
• South Shore Audubon Society
• Graduate Committee – Dr. Russell Burke, Dr. Ronald
Sarno, Dr. Darrell Frost, Dr. Chris Raxworthy
• My Family and LM Parker