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

Transcription

1 Guide to the monitoring of reptiles and amphibians of St. Eustatius Tim van Wagensveld & Bart Kluskens

2 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 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.

3 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:

4 2 Guide to the monitoring of reptiles and amphibians of St. Eustatius

5 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

6 All species Adequate data Evaluated Extinct (EX) Extinct in the Wild (EW) Threatened categories Critically Endangered (CR) Endangered (EN) Vulnerable (VU) Near Threatened (NT) Least Concern (LC) Exctinction risk Data Deficient (DD) Not Evaluated (NE) Figure 1. Diagram taken from 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

7 Table 1: The reptiles and amphibians of St. Eustatius Species Common name Scientific name IUCN Red list Frogs Geckos Tree lizards (Anoles) Johnstone s Whistling Frog Northern Leeward Dwarf Gecko Island Dwarf Gecko Common House Gecko Giant Woodslave Gecko Statia Bank Lizard Saint Kitts Bank Bush Anole Eleutherodactylus johnstonei i Sphaerodactylus sabanus* Sphaerodactylus sputator* Hemidactylus mabouia i Thecadactylus rapicauda* Anolis bimaculatus* Anolis schwartzi* Least concern Least concern Least concern Not evaluated Not evaluated Least concern Not evaluated Blindsnakes Wormsnake Rhamphotyphlops braminus i Not evaluated Snakes Iguana Ground Lizards Sea turtles Red-bellied Racer Lesser Antillean Iguana Red-faced Ground Lizard Leatherback Sea Turtle Alsophis rufiventris* Iguana delicatissima* Ameiva erythrocephala* Dermochelys coriacea Endangered Endangered Near threatened Vulnerable Green Sea Turtle Chelonia mydas Endangered Hawksbill Sea Turtle Eretmochelys imbricate Critically endangered * native to St. Eustatius. i Introduced. Guide to the monitoring of reptiles and amphibians of St. Eustatius 5

8 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 10m 2, and the markings make it easier 6 Guide to the monitoring of reptiles and amphibians of St. Eustatius

9 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 Stopwatch 1 Headlamp 2 1. Ten minutes per survey site 2. For night surveys Guide to the monitoring of reptiles and amphibians of St. Eustatius 7

10 Data that you collect can be uploaded on the website. See below for a field sheet example: Species Date Time Northern leeward dwarf gecko Island dwarf gecko Statia bank lizard St. Kitts bank bush anole Red-bellied racer Lesser Antillean iguana Red-faced ground lizard Johnstone s whistling frog 15/ / / / / / / / :30 10:30 10:30 10:30 10:30 10:30 10:30 18:30 Survey Point Route 1, point 1 Route 1, point 1 Route 1, point 1 Route 1, point 1 Route 1, point 1 Route 1, point 1 Route 1, point 1 Route 1, point 1 Day/ night survey Number of sightings Day 2 Day 1 Day 7 Day 18 Day 0 Day 0 Day 1 Category (frogs) Night 2 8 Guide to the monitoring of reptiles and amphibians of St. Eustatius

11 Map 1: Six different areas in the Quill National Park are indicated as routes. Routes 3 to 6 are along the around the mountain trail, and routes 1 and 2 are up the trail leading into the crater. Numbers along the route indicate a survey point. These survey points are indicated by markers on the actual path. Map 2: Survey trail within Boven National Park, that leads from the entrance all the way to Venus bay. Numbers along the route indicate a survey point. These survey points are indicated by markers on the actual path. Guide to the monitoring of reptiles and amphibians of St. Eustatius 9

12 10 Guide to the monitoring of reptiles and amphibians of St. Eustatius

13 SPECIES DESCRIPTION Have a look at the species description of the reptiles and amphibians on Statia to learn a little more of each species. So please help with conservation on St. Eustatius and take some time to do a few surveys! Guide to the monitoring of reptiles and amphibians of St. Eustatius 11

14 Johnstone s Whistling Frog (Eleutherodactylus johnstonei) Least Concern (LC) Johnstone s whistling frog is the only amphibian species on Statia. This small species is not native to Statia and was most likely introduced to the island with the help of humans. Due to their widespread nature throughout the Lesser Antilles, it is difficult to pin point where they originate from. They are highly adaptive frogs and have managed to spread across many islands. They are now even found on mainland south America and possibly in the United Kingdom as well! Description: Males and females differ in size as adults. Their maximum size range is: 17-25mm ( ) 17-35mm ( ). These frogs vary greatly in their colours and patterns. In general their back is brown to greyishbrown with usually one or two darker chevrons (inverted V-markings). Dorsal patterns can vary with individuals from a thin stripe down the middle of the back to a pair of bold stripes along the sides of the back. The ventral colour is light cream. The frogs lack webbing between the toes, and each toe has a round suction disk at the extremity. The eyes have a golden iris. Particularly at night, and sometimes in shaded areas during the day, they can be heard whistling. Males whistle a two-note call, the first note is a high pitch, followed by a lower pitch. Habitat: The highest densities can be found on the Quill, especially in areas that hold a lot of moisture. Lower densities occur across the rest of the island, except on the Cultuurvlakte plains, where they are unlikely to occur. They are also commonly found in and around gardens close to human presence. They can tolerate drier conditions as long as moist micro habitats are available. These micro habitats can be anything from e.g. bromeliads, logs, rock cover, human debris, and in between leaf litter. Food: The diet consists of Invertebrates, which are mainly small insects and small arthropods. Predators: Birds such as e.g. herons and pearly-eyed thrashers will eat them. Snakes are also known to frequently prey upon them. 12 Guide to the monitoring of reptiles and amphibians of St. Eustatius

15 Reproduction: Males will call to females from damp/wet places, with an increase of whistling during and after heavy rainfall. Males will call anywhere from ground level up to approximately 3m high. They will be sexually mature after approximately one year, and can lay eggs every two months. The eggs are laid in the same areas where frogs reside. Females will guard the eggs, and after hatching young frogs are immediately independent. (1) Johnstone s Whistling frog. (2) Johnstone s Whistling frog. (2) Johnstone s Whistling frog. Guide to the monitoring of reptiles and amphibians of St. Eustatius 13

16 Northern Leeward Dwarf Gecko (Sphaerodactylus sabanus) Least Concern (LC) The northern leeward dwarf gecko is the smallest reptile species on Statia. They are endemic to Saba and the St. Kitts bank. Despite their small geographic range they are locally common on Statia, and therefore their IUCN Red List assessment is of least concern. If you look carefully through leaf litter on a shaded forest floor, you will frequently see one dart away. They are quite difficult to spot, as they can move so quickly! Description: A dwarf gecko, of which males and females are of similar size, with a maximum head-body length of 29mm. Body colour may vary from light to dark brown, and the head/throat is often a dull orange. Eyes differ between individuals on St. Eustatius and Saba. On Statia individuals have a narrow yellow ring surrounding the pupil, whereas on Saba the eye is brown. They are predominantly active during the day, although direct sunlight is avoided to prevent desiccation (drying out). Locally they can be very common. Habitat: They are most commonly found on (shaded) forest floor in between, and under leaf litter. Food: Small invertebrates such as ants and termites are the most likely prey items. Predators: A range of animals undoubtedly predate on dwarf geckos, including birds, larger anolis lizards, woodslaves, red faced ground lizards, snakes, spiders, scorpions, centipedes and land crabs. Reproduction: Although nothing is known on the reproduction of this species, based on other day geckos a single egg is probably laid in rock crevices in leaf litter or bark. Gravid females have been found from May June. 14 Guide to the monitoring of reptiles and amphibians of St. Eustatius

17 (1) Northern Leeward Dwarf Gecko (Saba). (2) Northern Leeward Dwarf Gecko (St. Eustatius). Guide to the monitoring of reptiles and amphibians of St. Eustatius 15

18 Island Dwarf Gecko (Sphaerodactylus sputator) Least Concern (LC) The Island dwarf gecko is the larger of the two dwarf gecko (Sphaerodactylus sp.) species on Statia. They are endemic to the St. Kitts bank, and St. Maarten. These pretty geckos can be found under rocks during the day or wandering around at night. Look closely or they will be gone before you know it! Description: A relatively large dwarf gecko with head-body lengths up to 35mm. Females are slightly larger than males. These geckos are found along the St. Kitts bank, and St. Maarten. Habitat: Areas with many rocks on the ground, leaf litter on a forest floor. They are more tolerant of drier areas and are less common in heavily shaded areas unlike S. sabanus. They readily take advantage of manmade structures. Food: Small invertebrates such as ants, crickets, and termites are the most likely prey items. Predators: Although there are no accounts of predation, it is presumed that any birds that eat small reptiles, cats, ground lizards, crabs, larger woodslaves, both anolis species on the island, and possibly centipedes, spiders and scorpions, will eat Island dwarf geckos. Reproduction: Typically a single egg is laid in leaf litter, under rocks, in between crevices and bark. Gravid females can be found from February through June. 16 Guide to the monitoring of reptiles and amphibians of St. Eustatius

19 (1) Island Dwarf Gecko. Guide to the monitoring of reptiles and amphibians of St. Eustatius 17

20 Woodslave (Hemidactylus mabouia) Not Evaluated (NE) This gecko species can be commonly found throughout the tropics. They are usually observed climbing on walls close to a light at night. The light attracts insects, which is great for the geckos that eat them! Description: Woodslaves can grow up to 70mm of head-body length with females being slightly bigger. They have a flattened head which is considerably wider than the neck. The body colour ranges from greyish to light brown and is marked with brown V-shaped bands. The back is covered with small and granular dorsal scales interspersed with spikelike scales. These lizards have modified scales under the toes allowing them to climb vertical surfaces. Nocturnal. Habitat: Woodslaves can be found in and around human structures such as houses or abandoned ancient buildings. Here they hide in crevices, woodpiles, trash or water tanks. Food: These geckos are insectivorous and hunt generally during the evening on e.g. mosquitoes, moths, flies and midges. Predators: Snakes, cats, birds and larger sized lizards. Reproduction: Females reproduce year round and lay eggs one at the time. The small, approximately 10mm, white soft eggs stick to surfaces or in cracks in walls or tree bark. However females could also create communal nests containing larger clutches. Monitoring: Difficult to monitor. 18 Guide to the monitoring of reptiles and amphibians of St. Eustatius

21 (1) Woodslaves are common around human settlements. Guide to the monitoring of reptiles and amphibians of St. Eustatius 19

22 Giant Woodslave or Turnip tailed gecko (Thecadactylus rapicauda) Not Evaluated (NE) Giant woodslaves are a large species of gecko native to Statia. They are difficult to find as they are a nocturnal species, only active by night. They are rarely seen close to the ground and most are found up in trees. They can be found from mexico to Brazil and in the Lesser Antilles. Description: Giant Woodslaves are larger than common woodslaves attaining a head-body length of 125mm. The head is flattened and wider than the neck. These lizards have good camouflage and colour varies from pale greyish-white to darker brown with body patterns varying with crossbands, spots and stripes. Habitat: Unlike Woodslaves (Hemidactylus mabouia) these gecko s predominantly inhabit forested areas however they can be spotted on buildings, walls and fences but less abundant. Food: Giant woodslaves feed on a variety of nocturnal insects such as cockroaches, spiders and beetles. Predators: Snakes, cats and nocturnal birds. Adults might take advantage of their large body size and feed on smaller individuals of their own species. Reproduction: Eggs, near round and hardened shell, are produced year round and a single one is laid at the time. Females place their eggs in tree trunks, crevices and walls however eggs may also be buried. Monitoring: Difficult to monitor. 20 Guide to the monitoring of reptiles and amphibians of St. Eustatius

23 (1) Giant Woodslaves are usually found in between rock crevices and on trees. Guide to the monitoring of reptiles and amphibians of St. Eustatius 21

24 Statia Bank Lizard or Green tree lizard (Anolis bimaculatis) Least Concern (LC) These lizards belong to a Genus (a name for a group of related animals) called Anolis. This group also includes the other small tree lizard found on Statia called the St. Kitts bank bush anole. Found on the St. Christopher bank, their natural distribution is St. Kitts, Nevis and St. Eustatius. Especially males can have beautiful colouration! Description: Males display a brilliant blue and green colouration. They have an enlarged nuchal crest, and with their maximum headbody size of 12,3cm they are quite a large Anolis species. Females can attain a maximum head-body size of 7cm. Females exhibit a more dull colouration consisting mainly of brown with a yellow/green line along their sides that extends from the head to the base of the tail. They have a relatively small dewlap (flap of skin under the head) for an Anolis. They have a black spot just behind the front legs, and colours may vary from green-blue all the way to dark brown. Habitat: Generalist, Anolis bimaculatis can be found ranging from the top of the Quill to lower parts of town, where they readily make use of manmade structures. They can be found in cleared areas and forests. They predominantly occupy larger tree trunks, whereas A.schwartzi is much more common on the ground. Food: small invertebrates, and possibly smaller geckos and lizards including their own kind. Predators: Birds, cats, snakes, and red faced ground lizards may consume smaller individuals that venture onto the ground. Reproduction: A single egg is laid, that hatches just four weeks later. The eggs are laid in a hidden place. 22 Guide to the monitoring of reptiles and amphibians of St. Eustatius

25 (1) Female green tree lizards are smaller than males. (2) Male green tree lizard. (3) Green tree lizard males can vary greatly in their colouration. (4) Some male green tree lizards have brilliant colouration. Guide to the monitoring of reptiles and amphibians of St. Eustatius 23

26 Saint Kitts Bank Bush Anole (Anolis Schwartzi) Not Evaluated (NE) Like the Green tree lizard this species also belongs to the Anolis genus. They also have the same distribution, occuring on the St. Christopher bank. These small lizards are common on Statia, and due to their active life style they are very interesting to watch. They are most oftenly seen on the ground and low lying vegetation, where they will jump from one point to the other. Males will regularaly show off their beautiful yellow dewlaps. Description: These are relatively small anoles attaining a head-body size for males of 5,3cm, and 4,6cm for females. The base colour is a faint brown for both males and females. The males have a yellow drab colouration on their extremities, whereas females are duller brown with stripes along the lower sides. They have a yellow coloured dewlap that they can extend. Habitat: These anoles live mainly on the ground in between leaf litter and in shaded areas, sometimes in very high densities. They can be seen perching on grass, rocks and low lying vegetation. They readily adapt to manmade structures. And are found throughout most of the island. Food: Small invertebrates, and on occasion they may lap up nectar. Predators: Birds, snakes, and larger lizards. Reproduction: Like nearly all Anolis species, they lay a single egg that hatches after about four weeks. These eggs are laid in varying conspicuous areas, such as in between leaf litter and rock crevices. 24 Guide to the monitoring of reptiles and amphibians of St. Eustatius

27 (1)Male Saint Kitts Bank Bush Anole. (2) Male Saint Kitts Bank Bush Anole. Guide to the monitoring of reptiles and amphibians of St. Eustatius 25

28 Blindsnake or flowerpot snake (Indotyphlops braminus) Not Evaluated (NE) These snakes originate from the Indian subcontinent, but because of humans they can now be found nearly everywhere throughout the tropics. They honour their name as the flowerpot snake as they hide out in roots of plants. If these plants were decorative plants sold from island to island, you can see how these blindsnakes easily get to areas where they don t actually originate from. Description: Tiny/slender, total length ~ 175mm, scales cover eyes and are non-functional. Both head and tail blunt, tail is spike tipped typical for blindsnakes. Dark brown/black in colour. Can move quite fast despite their size. Habitat: under flat rocks cultuurvlakte, moist/damp soils. Native to Indian sub-continent, introduced, most probably via plants and roots, decorative plants. Food: Tiny insects (ants, termites) Predators: Unknown, could be mistaken as a worm when emerging above ground during showers, and thus taken by birds. Reproduction: Probably year round, as they live in a reasonably stable environment. The only known all female species, that will produce eggs even when not fertilized 1-8. Monitoring: Difficult to monitor. 26 Guide to the monitoring of reptiles and amphibians of St. Eustatius

29 (1) Flowerpot snakes are tiny, if you look closely at the head you can see a flickering tongue. Guide to the monitoring of reptiles and amphibians of St. Eustatius 27

30 Red-bellied racer (Alsophis rufiventris) Endangered (EN) The Red-bellied racer is the only species of snake native to Statia and is listed as an Endangered species. These harmless snakes are only found on Saba and Statia, having become extinct on St.Kitts & Nevis after the introduction of the asian mongoose on those islands. They are regularly seen in the Quill National Park, sunning in open patches on the forest floor. Description: head body length usually less than 1m, exceptionally large individuals may reach 1,5m. Colouration can vary considerably from dark brown to a light grey. Colour is related to sex, and also varies per individual. Habitat: Broad range from dry shrub land to humid forest. Usually on forest floor, where it blends in well with leaf litter, Also found regularly in shrubs. Food: Juvenile iguanas, lizards, frogs, birds and insects. Predators: Predatory birds (American kestrel, red tailed hawk), humans. Reproduction: Nothing none, other species of genus are egg layers. (1) Female Red bellied racer resting during the midday heat. 28 Guide to the monitoring of reptiles and amphibians of St. Eustatius

31 (2) Male Red bellied racer. (3) Female red bellied racer. (4) Male Red bellied racer. Guide to the monitoring of reptiles and amphibians of St. Eustatius 29

32 Red-faced ground lizard (Ameiva erythrocephala) Near Threatened (NT) These rather large Ameivas can only be found on Statia, St.Kitts & Nevis, although the species has suffered a serious decline on the latter two islands due to the asian mongoose. They are more common in open areas where they are commonly seen basking. Many can be seen in the same area foraging through leaf litter for food. Due to their limited range, the species is listed as Near Threatened. Description: The red faced ground lizard is a large member of the Ameiva genus, that derives its name from the red colouration on the head. Males can attain a head-body length (not including the tail) of 13,7cm, and females 9,7cm. Both males and females will tolerate each other which can lead to high densities of ameivas in some areas. Younger individuals have white stripes running along their bodies that fade with maturity. Habitat: Is well adapted to urban and disturbed areas. Does not occur in dense forest. Found in open areas with sporadic vegetation. Tolerates high temperatures well. Food: active foragers, often seen digging through leaf litter. opportunistic scavenger. Feeds mainly on insects but will also eat small lizards and their eggs. Predators: snakes, birds, mongooses, cats, dogs, Reproduction: seasonal, reproduction concentrated between May to October, 1-7 eggs laid. Larger females will lay larger clutches more frequently then smaller individuals. 30 Guide to the monitoring of reptiles and amphibians of St. Eustatius

33 (1) A juvenile red faced ground lizard that still has the characteristic white stripes along the flanks. (3) Close-up of a large male red faced ground lizard. (2) A pair of mating red faced ground lizards. The male can be seen biting the female in her flank to hold on. Guide to the monitoring of reptiles and amphibians of St. Eustatius 31

34 Lesser Antillean Iguana (Iguana delicatissima) Endangered (EN) The Lesser Antillean iguana once occurred in the Lesser Antilles from Anguilla in the North all the way to Martinique in the south. Sadly the overall population has declined dramatically, which has caused them to die out on many islands, including St. Maarten. The iguanas on St. Maarten today are another species called the green iguana (Iguana iguana). The Lesser Antillean iguana is now listed as endangered and are in need of protection to prevent them from dying out on Statia. Their decline is due to overhunting, loss of habitat, and hybridization with green iguanas, which means that hatchlings are a mix between the two species. Description: Males become larger and heavier than females and turn slate grey as they mature. Females retain much of their green colour as they age, although in some instances large females also turn grey. The largest recorded male on St. Eustatius was 131cm, and the largest female was 122cm. Juveniles are emerald green with a brown/black muffled colour towards the extremity of the tail. The green colour turns darker from the extremities towards the torso as they age, along with whitening of the jowls, jaw, throat and snout. Males have obvious white spots on the underside of their hind legs; these are femoral pores, and are much less distinct on females. Both males and females may exhibit pink cheeks, although this is usually much more clear in males, especially during mating season. At the base of their tails males have two clear hemipenal bulges, whereas the base of a females tail is flat. The size of iguanas can vary per island throughout their distribution. Habitat: The lesser Antillean iguana can survive in a broad range of environments from mangroves, xeric scrub, dry scrub woodland, humid forest (lower altitude portions of transitional rainforest), dry rocky shrub lands & dog-free gardens. Food: Iguanas eat leaves, fruits and flowers. They shift their diet from folivory (leaf matter) in the dry season to folivory and frugivory (fruits) in the wet season. 32 Guide to the monitoring of reptiles and amphibians of St. Eustatius

35 Predators: snakes, cats, dogs and for juveniles predatory birds and rats. Adults have no natural predators. Reproduction: Mating season is presumed to be April-May, and nesting presumed: June-July. Hatchlings emerge in October-November. Iguanas lay between eggs, although the amount varies per island. (1) A male Lesser Antillean iguana with a bead tag in his neck. Iguanas caught for scientific reasons are given a unique colour code made of beads. This will allow observers to distinguish between different individuals. (2) A male iguana up in the trees. Despite their size they can be quite difficult to spot. Guide to the monitoring of reptiles and amphibians of St. Eustatius 33

36 FIELD TABLE Species Date Time Northern leeward dwarf gecko Island dwarf gecko Statia bank lizard St. Kitts bank bush anole Red-bellied racer Lesser Antillean iguana Red-faced ground lizard Johnstone s whistling frog 34 Guide to the monitoring of reptiles and amphibians of St. Eustatius

37 Survey Point Day/night survey Number of sightings Category (frogs) Guide to the monitoring of reptiles and amphibians of St. Eustatius 35

38 APPENDIX I Table 2: Approximate coordinates of all the survey points in The Quill and Boven National Parks. Route 7 Route 6 Route 5 Route 4 Route 3 Route 2 Route 1 Survey Point GPS Coordinates N GPS Coordinates W Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Survey Guide to the monitoring of reptiles and amphibians of St. Eustatius

39 NOTES Guide to the monitoring of reptiles and amphibians of St. Eustatius 37

40 BIG THANK YOU TO: Dutch Caribbean Nature Alliance Safeguarding nature in the Dutch Caribbean FOR MAKING THIS PUBLICATION POSSIBLE 38 Guide to the monitoring of reptiles and amphibians of St. Eustatius