Guide to the monitoring of reptiles and amphibians of St. Eustatius Guide to the monitoring of

40 Pages·2017·2.24 MB·English

GGuuiiddee ttoo tthhee mmoonniittoorriinngg ooff rreeppttiilleess
aanndd aammpphhiibbiiaannss ooff SStt.. EEuussttaattiiuuss
Tim van Wagensveld
&
Bart Kluskens
Colophon
As part of the expedition of species richness and monitoring on St. Eustatius, The Guide to the monitoring of
reptiles and amphibians on St. Eustatius was made financially possible by the Prins Bernhard Cultuurfonds,
Caribbean. Created by: Stichting RAVON (Reptile Amphibian & Fish Conservation the Netherlands) &
SOSiguana, in cooperation with The Dutch Caribbean Nature Alliance (DCNA), and St. Eustatius National Parks
(STENAPA).
Ontsluiting expeditie monitoring soortenrijkdom op Statia is mogelijk geworden mede met financiële steun
van het Prins Bernard Cultuurfonds Caribisch Gebied.
Editors: Ronald Zollinger & Jöran Janse
Authors: Tim van Wagensveld & Bart Kluskens
Catalogue design: Robert Jan van Oosten
Acknowledgements: Elfriede Schotsmans, Hannah Madden & STENAPA.
© 2017 Stichting RAVON, Mercator III, Toernooiveld 1, 6525 ED Nijmegen, the Netherlands
All rights reserved. No part of this publication may be reproduced in any manner without permission. All
images are © Stichting RAVON, reproduced with the kind permission of the artists and/or their representatives.
Photo credits:
Front page: Lesser Antillean iguana by Jöran Janse.
Jöran Janse: Johntstone’s whistling frog (1-3); Northern Leeward Dwarf Gecko (1-2); Island Dwarf Gecko (1); Giant
Woodslave; Green Tree lizard (1-3); St. Kitts Bank Bush anole (1-2); Flowerpot snake (1); Red-bellied racer (2-4);
Red-faced ground lizard (1-3).
Tim van Wagensveld: Woodslave (1); Green Tree lizard (4); Red-bellied racer (1); Lesser Antillean iguana (1-2).
Figure credits: (Fig 1) IUCN Red List.
Map credits: Stichting RAVON, Tim van Wagensveld
Every effort has been made to contact copyright holders and to ensure that all the information presented
is correct. Some of the facts in this volume may be subject to debate or dispute. If proper copyright
acknowledgment has not been made, or for clarifications and corrections, please contact the publishers and
we will correct the information in future reprintings, if any.
Guide to the monitoring of reptiles
and amphibians of St. Eustatius
Tim van Wagensveld & Bart Kluskens
RAVON
Reptile Amphibian & Fish Conservation the Netherlands
This publication was made possible
through the generous support from:
2 Guide to the monitoring of reptiles and amphibians of St. Eustatius
INTRODUCTION
Reptiles are beautiful and fascinating animals. St. Eustatius (Statia) harbours
13 reptile, and one introduced amphibian species. Seven of the reptile
species are regionally endemic! This means that these seven species can
only be found in the Lesser Antilles. Currently two of these terrestrial
species are now classified as endangered, and one as near threatened
on IUCN’s Red List (Figure 1 & Table 1). This list gives an indication of how
well or bad different animal species are doing. All three sea turtles that
live around Statia are on the Red List threatened categories. Statia has to
cherish the few, and very unique species that are present on the island.
Very little is still known on most species on Statia, therefore any information
gathered through monitoring will greatly help towards conservation, and
saving the unique wildlife of Statia.
In order to monitor whether conservation efforts are paying off on Statia,
monitoring of reptile species is crucial. With the help of volunteers, nature
conservation organisations and the government we will be able to keep
a close eye on any population trends of the reptiles on Statia. Population
trends (whether a population is increasing, decreasing or stable) are
critical for a better understanding of species. With a clear view on a species
population trend, a decrease in numbers for example, will tell us that
measures need to be taken to stop any further decline. Furthermore this
booklet will aid in gathering insight towards the distribution of reptiles on
the island, and hopefully create the necessary awareness!
Guide to the monitoring of reptiles and amphibians of St. Eustatius 3
Extinct (EX)
Extinct in the Wild (EW)
Threatened categories
Critically Endangered (CR) Exc
Adequate data tin
Endangered (EN) ctio
n
Vulnerable (VU) risk
Evaluated
Near Threatened (NT)
All species Least Concern (LC)
Data Deficient (DD)
Not Evaluated (NE)
Figure 1. Diagram taken from www.iucnredlist.org. The diagram provides a clear overview of
the different categories in which animals are placed depending on their population status.
Both the Red bellied racer and Lesser Antillean iguana are in the orange Endangered (EN)
category. Animals in this category are at substantial risk of becoming extinct.
4 Guide to the monitoring of reptiles and amphibians of St. Eustatius
Table 1: The reptiles and amphibians of St. Eustatius

Species Common name Scientific name IUCN Red list
Johnstone’s Eleutherodactylus
Frogs Least concern
Whistling Frog johnstonei i
Northern Leeward Sphaerodactylus
Least concern
Dwarf Gecko sabanus*
Island Dwarf Sphaerodactylus
Least concern
Gecko sputator*
Geckos
Common House Hemidactylus
Not evaluated
Gecko mabouiai
Giant Woodslave Thecadactylus
Not evaluated
Gecko rapicauda*
Anolis
Statia Bank Lizard Least concern
bimaculatus*
Tree lizards
(Anoles)
Saint Kitts Bank
Anolis schwartzi* Not evaluated
Bush Anole
Rhamphotyphlops
Blindsnakes Wormsnake Not evaluated
braminusi
Alsophis
Snakes Red-bellied Racer Endangered
rufiventris*
Lesser Antillean Iguana
Iguana Endangered
Iguana delicatissima*
Red-faced Ground Ameiva
Ground Lizards Near threatened
Lizard erythrocephala*
Leatherback Sea Dermochelys
Vulnerable
Turtle coriacea
Sea turtles Green Sea Turtle Chelonia mydas Endangered
Hawksbill Sea Eretmochelys Critically
Turtle imbricate endangered
* native to St. Eustatius.
i Introduced.
Guide to the monitoring of reptiles and amphibians of St. Eustatius 5
MONITORING
Not all reptiles and amphibians that occur on St. Eustatius are relevant for
monitoring. Out of the fourteen species present only eight are endemic to
the island, of which four are very common: Northern Leeward Dwarf gecko,
Island Dwarf gecko, Giant woodslave, Statia Bank Tree anole and Saint Kitts
Bank Bush anole. The other three species either have a limited distribution,
occur at low densities or are internationally recognized as vulnerable or
threatened. The status of these target species provides valuable information
about the habitat conditions or the islands nature in general.
Monitoring occurs in areas where the target species are present. However,
the population status of a more common species provides very useful
additional information. E.g. the presence of Anolis schwartzi in an area for
monitoring the Red-bellied racer, as the latter species actively preys on Anolis.
Standardization is crucial
In order to measure the effect of nature management and conservation,
data is needed. Collecting data starts with following species in their natural
environment, in other words counting them.
To carefully interpret data it is crucial it is collected using identical methods.
Randomly doing an inventory in an area does not provide useful data.
Therefore this manual has been created to: instruct observers in order to
collect data everywhere in the same manner. The number of instructions is
limited, but necessary in order to get reliable results and to compare data
from year to year.
Surveys
On each coloured route (as seen on map 1 & 2) you will find coloured posts
that indicate a survey area. The coordinates for the different survey areas are
in Appendix I. The survey areas are 10m2, and the markings make it easier
6 Guide to the monitoring of reptiles and amphibians of St. Eustatius
for you to see the grid in which you can count animals. Each survey should
last ten minutes, this way you can also enjoy, and take in your surroundings.
Note the species and how many unique individuals you can see in the
designated area during the survey time. This method will work for: Anolis
schwartzi, Anolis bimaculatus, Alsophis rufiventrus, Ameiva erythrocephala,
Sphaerodactylus sabanus, Sphaerodactylus sputator. The survey can be done
during the day, but also at night! If you would like to do a night survey it is
important that you bring a powerful headlamp (500 lumen or more). Anolis
lizards and juvenile iguanas can be spotted sleeping in the bushes as they
light up in the beam of light from your flashlight. However, at night you
will not see: Alsophis rufiventrus and Ameiva erythrocephala as these sleep in
burrows during the night. Scan the forest floor for Sphaerodactylus geckos!
In general iguanas are difficult to spot, and they mostly live in the trees
rarely coming down to the ground. Opportunistic sightings, even outside
the marked grids should be noted along the survey trails.
Some species however are very difficult to spot and are actually easier
to count based on the sound that they make. Therefore the number of
Eleutherodactylus johnstonei are counted/estimated based on the number
of individuals that the observer can hear whistling. This is then put in one
of four classes: 0= No frogs; 1= rare (1-5 frogs can be heard); 2= common
(6-20 frogs can be heard); 3= very common (21+).
You will need the following equipment during a survey:
Survey sheet Pen / pencil Binoculars Stopwatch1 Headlamp2
1. Ten minutes per survey site 2. For night surveys
Guide to the monitoring of reptiles and amphibians of St. Eustatius 7
Data that you collect can be uploaded on the www.sosiguana.org website.
See below for a field sheet example:
Day/ Number
Survey Category
Species Date Time night of
Point (frogs)
survey sightings
Northern
15/01 Route 1,
leeward 10:30 Day 2
2017 point 1
dwarf gecko
Island dwarf 15/01 Route 1,
10:30 Day 1
gecko 2017 point 1
Statia bank 15/01 Route 1,
10:30 Day 7
lizard 2017 point 1
St. Kitts bank 15/01 Route 1,
10:30 Day 18
bush anole 2017 point 1
Red-bellied 15/01 Route 1,
10:30 Day 0
racer 2017 point 1
Lesser
15/01 Route 1,
Antillean 10:30 Day 0
2017 point 1
iguana
Red-faced 15/01 Route 1,
10:30 Day 1
ground lizard 2017 point 1
Johnstone’s 15/01 Route 1,
18:30 Night 2
whistling frog 2017 point 1

8 Guide to the monitoring of reptiles and amphibians of St. Eustatius