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2 3 MSc Conservation and Biodiversity 4 ASSIGNMENT COVER SHEET – Research Project 5 Student Name: Rhon Connor ....Uni. No: ………... 6 7 Project Title: Distribution, Habitat Association, Species Abundance and Perceptions of Residents 8 towards Achatina fulica in Anguilla 9 10 Supervisor: Dr Tom Tregenza 11 Date Submitted: 12th September 2006 Date Received ASU: 12th September 2006 12 13 Feedback: 14 15 16 17 18 Marker‟s signature 19 Mark: 20 Moderator‟s signature: 21 22 DECLARATION 23 24 I certify that this assignment is my own work. I confirm that I have not allowed anyone else to copy this work. 25 Any material quoted or paraphrased from references books, journals, www etc. has been identified and duly 26 acknowledged or references as such. I have read the University‟s policy on plagiarism. 27 28 Signed………………………………………………………………………………… 29
Rhon Connor – MSc paper 1 30 Cover page
31 Title: Distribution, Habitat Association, Species Abundance and Perceptions of Residents towards
32 Achatina fulica in Anguilla
33 Rhon A. Connor
34 Postal address: Rendezvous Bay, Anguilla, British West Indies.
35 Corresponding author e:mail: [email protected]
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Rhon Connor – MSc paper 2 41 Abstract
42 Invasive species affect biodiversity and have been associated with high economic costs and other
43 implications for society. One invasive mollusc, which is currently causing considerable damage to the
44 livelihood of people in the Caribbean, is the Giant African Snail (Achatina fulica). The invasion of this
45 mollusc in the Caribbean Island of Anguilla has posed a major challenge to the authorities and
46 residents alike. Here, I investigated the overall distribution of A. fulica, examined the association of A.
47 fulica with three different habitats (grasslands, woodlands and shrubs), recorded its microhabitats, and
48 probe the perception of residents towards the introduced mollusc. I found that there were significant
49 differences in the snails‟ abundance among geographic areas, habitat types and microhabitats. The
50 results indicated that A. fulica was widely distributed in all major habitat types, thereby suggesting that
51 any eradication programme will be extremely costly. The study also revealed that residents
52 considered the snail to be a pest and were supportive of assisting the authorities in managing the
53 destructive mollusc.
54
55
56 Key Words
57 Giant African snail, invasive species, microhabitat, mollusc, biodiversity, Anguilla, pest.
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Rhon Connor – MSc paper 3 62 Introduction
63 Biological invasions (invasive or alien species) are harmful non-native animals, plants and
64 microorganisms that have the potential to affect terrestrial and marine biodiversity (Perring et al.,
65 2002; Mooney, 2005). In recent times, they have been viewed as a global threat to biodiversity and
66 conservation managers (Simberloof, 2002). These alien species, once established outside of their
67 native range, have the potential to severely alter native ecosystems (Gabriel et al., 2001).
68 Additionally, research has shown that oceanic islands are not only more vulnerable, but suffer greater
69 damage as a result of invasive species (Donlan et al., 2003; Dowd et al 2003). Scientists attribute this
70 theory to many factors, one being that these agents/vectors are away from their natural enemies
71 (predator, parasites, and pathogens), and therefore they have the freedom to adapt and spread rapidly
72 in their new environment (Dowd et al 2003, Molongoy et al 2006). Additionally, studies have
73 associated invasive species with the cause of extinctions in some islands (Donlan et al 2003; Gurevitch
74 and Padilla, 2004).
75
76 The island of Anguilla and the rest of the Caribbean Region are no strangers to invasive
77 species. According to Kairo and Ali (2003), the Caribbean region has a total of 552 invasive species
78 (of which Anguilla have 9). These include various species of snakes, insects, noxious weeds and other
79 micro-organisms which have altered the region‟s ecosystems, affected its economies and posed a
80 serious threat to the health and well being of the residents. One particular invasive which is currently
81 seen as a major threat to the Caribbean Region is the Giant African snail (Achatina fulica), whose
82 origin is Eastern Africa.
83
84 Achatina fulica is recognized by the Global Invasive Species Programme (GISP), as one of the
85 100 most destructive biological invasions in the world. This herbivore has a voracious appetite and is
86 known to feed on over 500 species of plants (Simberloof, 2003). Apart from this, A. fulica poses a
87 potential health risk to humans, as some of its specimens are associated with an intermediate host of a
88 nematode parasite Angiostrongylus Cantonensis, which is commonly known as the rat lung worm
Rhon Connor – MSc paper 4 89 (Civeyrel and Simberloff , 1996; Carvalho et al 2003). This vector has the potential to cause
90 eosinophilic meningoencephalitis and brain damage in humans (Upatham et al 1988).
91
92 The first known record of A. fulica in the Caribbean Region was documented in the French
93 island of Guadeloupe in 1984 (Mead and Palcy, 1992; Civeyrel and Simberloff, 1996; Raut and
94 Barker, 2002). Subsequently, specimens of A.fulica have dispersed and successfully established
95 populations in other islands of the Caribbean archipelago including Martinique (1988), Barbados
96 (2000), St. Lucia (2000), St. Maarten/St. Martin (2000?) and Anguilla (2000).
97
98 As in many other nations, the authorities and the residents throughout Anguilla are concerned
99 about the potential threat of the Giant African Snail. This concern has propelled the authorities to
100 launch an organized campaign towards the eradication of this invasive mollusc. However, due to
101 concerns voiced by a few concerned citizens (over the possible side effects of the molluscicide bait
102 being use), the campaign was prematurely stopped after three months.
103
104 It is important to note that although several scientific studies have been conducted on Achatina
105 fulica throughout the Pacific region, most of them have focused on its potential as a disease carrier, its
106 agricultural impact and/or various biological and natural attempts to control the mollusc. A review of
107 other literature simply provided an overview of the snails‟ biology and its potential use as a food
108 source. However, this is the first study to assess Achatina fulica in various parameters within its
109 physical environs, while at the same time evaluating it socio-economic impact on society. Therefore,
110 this study was designed to investigate a) the distribution of A. fulica in Anguilla, b) the topographical
111 habit of A. fulica, c) the physical location/micro-habitat associated with A. fulica and c) the perception
112 of residents towards A. fulica. In addition, as there are no preliminary data on endemic or introduced
113 snails on Anguilla, baseline data was also collected on specimens of the island‟s terrestrial
114 malacofauna.
115
Rhon Connor – MSc paper 5 116 The main predictions tested in this study are that there will be significant differences in the distribution
117 of A. fulica among villages, habitat types, microhabitats, and that the perception of residents in relation
118 to the mollusc will be dependent on the level of impact they have experienced as a result of the
119 invasive snails.
120
121 Materials and Methods
122 This study was conducted on the island of Anguilla (18.2 N, 63.1W ) from March to July
123 2006. The approach for this research took the form of two components, namely, extensive fieldwork
124 whereby data was collected from several sampling sites, and the distribution of a questionnaire, which
125 sought to ascertain the perception of residents towards the invasive A. fulica.
126
127 Rapid survey of the islands for Achatina fulica
128 Prior to the commencement of sampling study sites, I gathered information from the
129 Department of Agriculture in order to ascertain the distribution of A. fulica on the island. I then
130 conducted a rapid assessment throughout all of the villages (including those not listed by Department
131 of Agriculture) to ascertain the presence or absence of A. fulica on the island. This approach involved
132 having brief informal discussions with 5-10 residents (selected at random) from villages throughout
133 the island to determine whether they have seen or heard of the mollusc in their community. Once the
134 residents identified areas in their community where A. fulica was known to inhabit the area was
135 searched for a fixed period of 20 minutes for evidence (live snails or shells) of the introduced mollusc.
136 Those villages that provided evidence of a positive infestation of the mollusc were recorded and a GPS
137 unit was used to determine the exact location of the specimen(s). Upon completion of the research,
138 villages that were not infested with A. fulica during the initial rapid assessment survey were re-visited
139 to determine whether infestation of the snails had occurred in the area.
140
141 Study Sites
142 For the purpose of this research, the study sites were selected from the list of those villages
143 that were positively infested with specimens of A. fulica during the initial rapid assessment survey of
Rhon Connor – MSc paper 6 144 villages. Five of these villages were randomly chosen for sampling the distribution of the introduced
145 snail. These villages were Upper South Hill, Little Harbour, Stoney Ground, George Hill and Cauls
146 Bottom (see Fig. 1). It is important to note that for each study site, I examined three fairly
147 homogenous distinct topographic structures (habitats). These habitats were categorized as grasslands
148 (5-10 cm tall), shrublands (35-75 cm tall) and woodlands. The vegetation on the island does not have a
149 distinct woodland habitat. Therefore, in keeping with the range established by Walker et. al (2005),
150 areas with trees between 305-915 cm were classified as woodlands type habitats.
151
152 Criteria for site selection
153 I examined each of the five villages in the study to allocate areas that were suitable to be
154 classified as grasslands, shrublands and woodlands. Areas with dense vegetation are extremely
155 difficult to conduct sampling of poorly mobile organisms (Craze and Mauremootoo, 2002). Therefore
156 areas with semi-scattered and accessible vegetation were selected for sampling A. fulica‟s abundance
157 in shrubland and woodland type habitats. However, the final criterion for the site selection of the
158 mollusc was that the areas under investigation must have had at least two dead (shells) and live
159 specimens of the species Achatina fulica.
160
161 Sampling of sites
162 Achatina fulica is mainly nocturnal, therefore sampling only took place during the early
163 morning (at the break of dawn) when the snails were still very active. In order to ascertain the density
164 of A. fulica in each habitat, I randomly established a ten (10) metre transect- with 2 x 2 m quadrats -
165 on alternate sides for the grassland study sites (each transect had 5 quadrats). Subsequent transects
166 were established every 10 metres. This process was repeated 8 times, giving the sampled area a total
167 of 40 quadrats (N=40) for each grassland habitat. Again, due to the level of difficulty associated with
168 constructing quadrats in dense vegetation, the sampling technique for shrublands and woodlands were
169 slightly altered. Sampled areas were selected based on accessibility. However, the same number and
170 size of quadrats for these sites was constructed. Using the protocol established for other studies on
171 mollusc (see Cowie, 1999), timed sampling (5 minutes) was used to sample each quadrat. For each
Rhon Connor – MSc paper 7 172 quadrat, I scoured for A. fulica in various physical locations/microhabitats such as in the leaf litter, on
173 vegetation, under rocks/fallen wood, on tree trucks and on rocks/stony ground. For grassland habitats,
174 snails embedded in the grass were recorded as being in the leaf litter. A total of 600 quadrats were
175 sampled for this study (N=600).
176
177 All individuals of A. fulica that were in each quadrat were then counted, and its physical
178 location/microhabitat association (live specimens) was documented on a data sheet. Additionally, all
179 other species of gastropods that were found in the quadrats were recorded with reference to their
180 morphology. A hand held Garmin Foretrea 201 GPS (Garmin, Kansas, USA) unit was utilized for
181 acquiring the coordinates of all quadrats on the study site. Since wet weather is usually associated
182 with A. fulica being more active, the weather condition was also recorded on the data sheet. Wet days
183 were defined as overnight rain or the presence of dew in the habitat during the sampling, while dry
184 days were defined as the lack of precipitation in the habitat under study.
185
186 Interviews/Survey
187 The perception and participation of the public is an integral component when addressing the
188 issue of invasive species (Simberloof, 2003; Maguire, 2004; Gewin, 2005). Therefore, I conducted a
189 survey to ascertain the views of the public with reference to A. fulica. I designed a questionnaire and
190 randomly interviewed 140 residents (N=140) on the island. The survey was distributed to households
191 of infested villages (not necessarily those villages of the study sites). One individual (18 years or
192 older) from each household was asked a range of questions including (but not limited to), time of
193 introduction, methods of control and impact of snails (see appendix 1). It was hoped that by acquiring
194 such vital feedback from the respondents, the practitioners, residents and environmental managers
195 would have a better understanding of the impact of invasive species in relation to socio-economic
196 factors.
197
Rhon Connor – MSc paper 8 198 Results
199 Distribution of A. fulica
200 The survey indicated that 20 villages were infested with specimens of A. fulica. All of the
201 infested areas were adjoining villages. There were a total of 17 villages that were infested prior to the
202 commencement of the study, while 3 villages became infested during or after that period. At the
203 completion of the survey, only one village to the west (Long Bay) and the most eastern villages of the
204 island were free of the introduced snail (Fig. 1).
205
206 Abundance and Microhabitat/physical location
207 The survey yielded a total of 2,544 snails (876 live and 1668 dead) belonging to the species
208 Achatina fulica that were collected from the sampled sites. I performed a Kruskal-Wallis test
209 (adjusted for ties) to determine whether there were significant differences in the number of snails
210 among villages. The results (H=49.6, d.f=4, P < 0.001) indicated that there were significant
211 differences in the number of snails among villages. This test was also performed to determine whether
212 there was a significant difference in the number of snails among the 3 vegetation types. According to
213 the result (H=63.16, d.f =2, P < 0.001), it indicates that there were significant differences among the
214 snails in different habitat types.
215
216 The data further showed that the village of Stoney Ground had the highest density of A. fulica,
217 while George Hill had the least amount of these snails. However, the study indicated that the village
218 of South Hill had the highest density of live A. fulica, while Caul‟s Bottom had the least amount of
219 live snails (fig. 2). In terms of the dead A. fulica, Stoney Ground recorded the highest density of the
220 species per square metre, whereas George Hill had the least amount of snails. Additionally, the data
221 indicated that there were similar numbers of live and dead A. fulica in George Hill and South Hill (Fig.
222 2).
223
224 Further, with reference to habitat association, the survey indicated that shrublands recorded
225 the highest mean number of A. fulica per quadrat from the sampled population, while the woodland
Rhon Connor – MSc paper 9 226 habitats had the least number of this invasive mollusc (Fig.3). A higher biomass of A. fulica was
227 recorded in the shrubs at Stoney Ground, while Caul‟s Bottom had the least in this habitat. The data
228 also indicated that A.fulica was more prevalent in the woodland habitats of Caul‟s Bottom and George
229 Hill, whereas Little Harbour recorded the least amount of snails in this habitat. The results revealed
230 that there were a fairly even distribution of A. fulica among the woodland and grassland habitats of
231 South Hill and Stoney Ground (Fig.3).
232
233 The survey also indicated that among the three topographical structures under investigation,
234 grasslands were associated with a higher proportion of dead snails when compared to shrublands and
235 woodlands habitat. Alternatively, shrublands were associated with a higher proportion of live snails,
236 while woodland habitats recorded the lowest number of A. fulica snails for this study (see Figs.8
237 a,b,c).
238
239 This study also evaluated the physical location/microhabitat of Achatina fulica. Most of the
240 snails were located on the vegetation during the sampling of habitats (Fig.4). With the exception of
241 Stoney Ground, the data showed that there were very few snails located under the rocks or fallen
242 wood. Meanwhile, there were inconsistencies in terms of the amount of snails located in the leaf litter
243 and on rocks/stony ground for each of the sampled villages. However, the results indicated that the
244 amount of snails found on the tree trunks of the sampled villages were more evenly distributed when
245 compared to the other microhabitats (Fig.4). Additionally, the results also indicated that more live
246 specimens of A. fulica were recorded on wet days compared to dry (Fig. 8 d).
247
248 Other Species of Snails
249 The survey yielded a total of 5, 358 specimens of other mollusc species on Anguilla. These
250 terrestrial molluscs are further classified into six species, namely: Species 1) Drymaeus species- D.
251 virgulatus (family Bulimulidae); species 2) Bulimulus guadalupensis (family Bulimulida); species 3)
252 Chondropoma (Chondropomorus) (family Annulariidae/Licinidae); species 4) Macroceramus (family
253 Urocoptidae; species 5) Drymaeus species- (family Bulimulidi)striped; species 6) Subulinidae species
Rhon Connor – MSc paper 10 254 (see Fig. 5). Species 1 and 3 were found in all sampled villages. Species 2 was recorded in all villages
255 except Stoney Ground. The data also indicated that specimens of species 4 were only found in George
256 Hill and Little Harbour. Species 5 and 6 were only found in little harbour- and were exclusively
257 associated with the woodland habitats (table 1). The data also indicated that the density of A.fulica was
258 relatively close to the most common snail found in the island (table 2).
259
260 Although not recorded in the quadrat sampling, 2 other species of invasive molluscs-
261 Zachrysia Species Z. provisoria or Z. auricoma havenensis (family Pleurodontidae), (Fig.6) and a
262 number of veronicellid slugs were found in some villages during the period when the initial rapid
263 assessment survey for the presence/absence of A. fulica was conducted.
264
265 Perception of the Public
266 Results from the residential survey indicate that 42% of the respondents considered the Giant
267 African Snail to be a major/significant problem while 37% of them viewed it as a pest. (Fig. 7a). I
268 performed a regression test to ascertain whether there was a relationship between the amount of snails
269 in the respondents‟ yard and their perception of the molluscs. The results (r square=0.026, F=3.27, d.f
270 =1,121, P=0.07) indicated that there were no significant relationship with the amount of snails and the
271 perception of residents toward A. fulica. Again this test was performed to ascertain whether the
272 financial loss they experienced as a result of the snails had any bearing on their perception of the
273 mollusc. The results, r square =0.710, F=223.45, d.f =1, 90, p < 0.05, indicated that there is significant
274 relationship between financial losses and perception of snails. Similarly, a regression test suggested
275 that there is significant relationship ( r square=0.787, F = 497.91, d.f = 1, 35, p < 0.05) with reference
276 to the respondents age and their perception of the introduced snail.
277
278 Further, most respondents (44%) stated that the snails have also caused significant damage to
279 their plants/crops (Fig. 7b). In terms of mitigation methods, the majority of the respondents (50%)
280 utilized household salt as a mean of controlling A. fulica while 15% used metaldehyde bait to combat
Rhon Connor – MSc paper 11 281 these herbivorous snails (Fig. 7l). With reference to the geographic origin of A. fulica, 90% of the
282 respondents indicated that they were unaware of the area from which this species originated. (Fig 7d).
283
284 Only 2% of the sampled population indicated that they had seen the snail on the island from as
285 early as 1999, while 52% became aware of the snail‟s existence in 2005 (Fig 7e). The results also
286 indicated that most residents (44%) shared a view that the snail was introduced through the
287 importation of plants (Fig. 7c). In terms of eradication of the mollusc, 50% of the respondents stated
288 that the Government of Anguilla should take measures to eradicate A. fulica, while 37% believed that
289 the authorities should resort to using chemicals as a means of controlling them (Fig.7f). Only 2% of
290 the respondents were supportive of the idea of using the snail as a source of food.
291
292 Data from the questionnaire also indicated that 50% of the respondents believed that a special
293 task force should be created to combat A. fulica, while 35% were of the opinion that it is the
294 responsibility of the Department of Agriculture (Fig.7g). In relation to the question about the A . fulica
295 as a potential disease carrier, 46% of the respondents stated that they were aware that the mollusc may
296 be a risk to their health (Fig. 7h).
297
298 Interestingly, the questionnaire also revealed that most of the respondents (78%) were not only
299 willing to actively participate in an eradication programme, but were also willing to make a financial
300 contribution (83%) towards the eradication of A. fulica (Figs. 7i and 7j). To examine this further, I
301 performed a 2x2 chi square test to ascertain whether the respondents‟ willingness to physically
302 participate in an eradication programme were influenced by them having snails in their yard. The
303 results, square = -0.03, p=1 shows that there is no significant relationship between respondents
304 willingness to participate in an eradication programme and having/not having A. fulica in their yards.
305 Again, this same test was performed to evaluate whether the respondents willingness to pay a
306 contribution towards eradication of the mollusc were related to them having/not having the snail in
307 their yard. The results, square = -0.02, p = 1, shows that there is no difference between persons
Rhon Connor – MSc paper 12 308 willingness to pay and the presence or absence of snails in their yard. As to the issue of who held the
309 ultimate responsibility for eradication of the snails, the results indicated that the prevailing view was
310 that it was the responsibility of all stakeholders (Fig. 7k).
311
312 Discussion
313 This study has indicated that Achitina fulica has successfully manifested and established itself
314 within Anguilla‟s ecological community. With the exception of the villages to the eastern end of the
315 island (Fig. 1), this introduced mollusc has invaded all other communities throughout the island. It
316 must be noted, however, that during the search for study sites the distribution of A.fulica seems
317 somewhat sporadic within the villages. The landscape that was modified had a tendency to be
318 affiliated with an abundance of the snails, while the more undisturbed areas were free of the
319 introduced mollusc. This suggests that A.fulica has a high affinity towards modified habitats. Although
320 With (2002) states that satellite population of newly invasive species is common, this observation has
321 been documented in several other studies on the invasive mollusc, which showed that A. fulica was
322 more prevalent in anthropogenic and disturbed habitats such as gardens, roadsides, wastelands (
323 Cowie, 1998; Meyers and Picot 2001; Raut and Barker, 2002).
324
325 The trend and rapid dispersal of A. fulica on Anguilla is of great interest. Tomiyama and
326 Nikane (1993) in their radio transmitter experiment to monitor the movement of the species observed
327 that the snails moved in a straight line and that their movement is within limited areas. Perhaps this is
328 the reason why the adjoining villages in the island are gradually being infested with these invasive
329 snails. Singh (1980) also observed a similar pattern of movement in his study of A. fulica in the Bihar
330 States. Another striking point about the migration of these snails is that they seem to be following a
331 westward movement throughout the island. This pattern of movement is quite interesting as most of
332 the tourism related facilities, which employ a significant amount of Anguilla‟s labour force, are
333 located on the western end of the island. This movement may suggest humans are aiding in the
334 dispersal of A. fulica (most likely attached to their vehicles). Kierans et al (2005) observed a similar
335 pattern of dispersal with their study on another invasive mollusc.
Rhon Connor – MSc paper 13 336
337 The abundance of A. fulica on the study sites, although not surprising, is also of great concern
338 to conservation managers and residents on Anguilla, as it indicates the high level of fecundity and easy
339 dispersal that is often associated with these pestiferous snails (Raut and Barker, 2002). Meyers and
340 Picot (2001) states that the snails have reached extremely high densities and biomass (up to 770kg/ha)
341 in New Caledonia. Similarly, the Caribbean island of Martinique has experienced the rapid spread of
342 A. fulica, as its infested area grew from 90 to 310 hectares within one year (Civeyrell and Simberloff,
343 1996). By contrast, the sampled village of South Hill recorded the highest density of live snails
344 (0.66m2). Therefore, with the average weight of A. fulica listed by the GISP at 32g, this suggests that
345 Anguilla‟s A.fulica population is likely to be 221 kg/ha.
346
347 This study also revealed that there were variations in the number of A. fulica among the
348 sampled villages, habitat types, and microhabitats (Fig. 2; Fig. 8a,b,c). As illustrated in the results, I
349 expected Stoney Ground to have a higher biomass of the mollusc. My rationale for this statement is
350 based on reports from the Department of Agriculture that the first known specimens of A fulica were
351 documented in that village (Christopher, 2006 as per. Comm.). This suggests that A.fulica’s biomass in
352 each of the sampled villages may be related to the time of its initial invasion. In terms of A. fulica‟s
353 microhabitat, the abundance of snails on the vegetation suggests that most of the mollusc were
354 foraging during the time the study was conducted; therefore, this study suggests that assessing
355 A.fulica’s microhabitat may be dependent on time of sampling.
356
357 With reference to habitat association of A. fulica, I expected to see higher density within the
358 woodland habitats, as the snails have a preference for dense vegetation (Thangavelu and Singh, 1983;
359 Craze and Mauremotoo, 2002). That the results showed higher densities were associated with
360 shublands and grasslands (Fig. 8b,c) suggests that the low biomass in woodland may be due to A.
361 fulica‟s recent colonisation of this type of habitat. Alternatively, the study revealed that apart from
362 physically being on the vegetation, most specimens of the mollusc were located in the leaf litter, which
Rhon Connor – MSc paper 14 363 is another common microhabitat of this species (Craze and Mauremotoo, 2002; Prasad, 2004). This
364 indicates that A. fulica may have a preference for this type of environment.
365
366 The data also revealed that there are a high percentage of dead A. fulica (66%) in Anguilla‟s
367 sampled population. Most literature states the A. fulica‟s population reaches high densities and then
368 the population drastically declines (Civeyrell and Simberloff, 1996; Meyers and Picot, 2001; Craze
369 and Mauremooto, 2002; Gervin, 2005). As mentioned by Cowie (1998) and Gerlach (2001), this
370 phenomenon (mortality rate) seems to be a common trend on islands that A. fulica had invaded. Other
371 sources have suggested that this drastic decline may be associated with epizootic diseases and lesions
372 (Mead, 1961; Mead and Palcy, 1992), lack of genetic diversity (Civeyell and Simberloff 1996) and the
373 species reaching its carrying capacity (Simberloff and Gibbons 2004). Certainly, the death of the snails
374 at the study sites is not associated with the metaldehyde-baiting programme that was initiated by the
375 Agriculture Department, as those areas were not treated.
376
377 Interestingly, Mead (1961) argues that the radiation from the sun also plays a role in
378 dehydrating and subsequently killing A. fulica. In this study, I observed that the highest density of
379 empty shells of this mollusc was mainly distributed throughout the grassland habitats that were
380 sampled. Therefore, I postulate that with reference to the three topographical structures under
381 investigation, the sun was better able to penetrate the thin grasslands, thereby causing a higher
382 percentage of snails to die in this habitat. Apart from this, I observed that a high density of dead A.
383 fulica was recorded in the grasslands in George Hill (Fig. 8c). Coincidentally, the said area is low
384 lying and was observed flooded on two occasions during the study. Since it takes less that 12 hours for
385 mollusc to drown, I postulate that the high number of snails found dead in this grassland habitat may
386 have been influenced by flooding. It is interesting to note that one beneficiary of the invasive snail is
387 the Caribbean Hermit Crab (Coenobita clypeatus), as it has been observed utilizing the shells of
388 A.fulica on several occasions during the study (see appendix 2). Sant‟Anna et al. (2005) have
389 reported a similar pattern of behaviour in A. fulica infested Brazil.
Rhon Connor – MSc paper 15 390 With regards to the other species of mollusc found in Anguilla, I observed that it was very rare
391 to find live specimens in the sampled quadrats. Some invasive organisms are known to have
392 deleterious effects on endemic species (Gurevitch and Padilla, 2004). For example, the mud snail
393 (Ilyanassa obsoleta) has been known to cause niche displacement on other species of snails (Mooney
394 2001) while the rosy wolf snail (Euglandina rosea) has been associated with the extinction of
395 Hawaii‟s endemic snails (Cowie, 1998; Gerlarch, 2001; Simberloof, 2003). Although A. fulica is not
396 associated with carnivorous activities, its vigorous and aggressive behaviour is associated with
397 competition and even replacement of native snail species (Craze and Mauremootoo, 2002; Mead and
398 Palcy, 2002). This suggests that the invasive A. fulica has potential implications for Anguilla‟s native
399 malacofauna. However, since the population data of the island‟s snails are not available this warrants
400 further research.
401
402 Results from the household survey indicate that the invasion of A. fulica in Anguilla is posing
403 a major challenge to residents and authorities. On several occasions during the study residents were
404 observed removing, baiting, and in some instances burning shrubs from their surroundings to destroy
405 these pestiferous snails (see appendix 3). Most residents resort to salt as a means of controlling the
406 invasive mollusc, but they also believe that the snail bait would be the most effective method of
407 management. Thangavelu and Singh (1993) states that a combination of both methods was most
408 effective in the management of the polyphagous snails. However, the residents and the authorities
409 must be cautioned that most molluscicides are not host specific, (Panigrahi and Raut, 2002; Prasad et
410 al., 2004; Gervin, 2005) and therefore have the potential to implicate other molluscs or non- target
411 species.
412
413 The survey also indicated that most residents did not view hand picking and destroying the
414 snails as a viable and practical method of control. Gerlach (2001) argues that manual collection of A.
415 fulica in the Seychelles (a particular area) was followed by a 98.3% decline of the said species.
416 Similarly, other sources (Mead, 1961; Raut and Barker, 2002) also reported that some populations of
417 A.fulica almost reached to the point of local extinction when this practice was initiated. Although
Rhon Connor – MSc paper 16 418 manual collection is quite a tedious and laborious task, and may be more effective with small and
419 incipient populations of A. fulica, authorities in Anguilla may want to consider this option as a means
420 of managing and controlling the spread of the invasive mollusc.
421
422 Further, the study also revealed that residents on the island of Anguilla are eager to launch a
423 collaborative effort to combat, and subsequently eradicate A. fulica. However, it is well known that
424 the longevity of such willingness and enthusiasm expressed by volunteers is short lived. Mead (1961)
425 states that in Southern China, residents were given free bait by the authorities to help control the
426 prolific dispersal of A.fulica, but the authorities had to subsequently halt the programme after some
427 residents expressed their views that it was the government‟s responsibility for controlling the snails.
428 Interestingly, although the respondents indicated a strong sense of willingness for collaboration with
429 the authorities, similar attitudes and sentiments have been expressed throughout the Anguillian
430 community. This suggests that the authorities should be cautious when distributing mollusc bait, and
431 soliciting the help of the wider community.
432
433 It is well established that A. fulica is an agricultural and horticultural pest (Thaguvelu and
434 Singh, 1983; Prasad, 2004; Gervin, 2005). Therefore, it is not surprising to note that most respondents
435 have suffered significant damage to their crops/plants. However, a potential concern for conservation
436 managers is the likely impact A. fulica will have on Anguilla‟s only endemic plant (Rondeletia
437 anguillensis). Sharp spines and small leaves characterize this small stiff shrub-like plant, which is
438 mainly distributed in the northern and eastern end of the island (Walker et al.2005). It is interesting to
439 note that the molluscs are already present in one of the villages (North Side) where this plant is found.
440 Although the snails have not spread to R. anguillensis habitat (limestone holes) in the said village, the
441 mollusc has been sampled in the woodlands of South Hill, which is a similar habitat of this plant, and
442 has been observed foraging on similar plant with thorns. This suggests that A. fulica has the potential
443 to invade and possibly threaten R. anguillensis’ ecological community. Perhaps conservation
444 managers in Anguilla may want to know that the authorities in La Reunion Island and Ile Aux
445 Aigrettes have already taken protective and eradicative measures to safeguard their rare and endemic
Rhon Connor – MSc paper 17 446 plants from A. fulica (Meyers and Picot, 2001; Craze and Mauremootoo, 2002). However, the likely
447 impact of A. fulica on Anguilla‟s endemic plant remains speculative, and therefore warrants further
448 research.
449
450 This survey indicates that invasive species can have serious implications for both biological
451 ecosystems and its inhabitants. It also indicates that Achatina fulica has spread throughout the various
452 topographical features within Anguilla. Additionally, with its high rate of recruitment, compounded by
453 the absence of its usual competitors, predators and other associates, A. fulica‟s population is not only
454 capable of sustaining itself, but it is also destined to manifest itself throughout the entire island within
455 a relatively short period. The study also demonstrated that feedback from the public is an integral
456 “tool” when addressing ways of managing and controlling invasive species, and also indicated that the
457 residents throughout the island are not only concerned, but are willing to collaborate with the
458 authorities and play their role in controlling the introduced mollusc. Additionally, since this is the first
459 known malacofauna study to be conducted on the island, the information gathered in this study will be
460 beneficial to any individual who wants to investigate invasive species and other studies on the
461 terrestrial snails of Anguilla and the Caribbean Region. Most importantly, however, this study
462 provides decision makers on the island with empirical data to help them facilitate strategic plans when
463 addressing the issue of the invasive Achatina fulica.
464
465 Conclusion and Recommendations
466 This study has shown that A. fulica has rapidly dispersed throughout the Caribbean island of
467 Anguilla, and is likely to have serious implications for the island's environmental managers. It is
468 obvious that A. fulica‟s population is well established throughout the island, and the initial phase of its
469 containment has been greatly missed. Therefore any thoughts of eradicating this invasive mollusc are
470 most likely to be futile. This is based on reports that although Florida (USA) and Queensland
471 (Australia) have successfully eradicated Achatina fulica, all others attempts throughout the Pacific
472 have completely failed. Thus, the authorities on the island should focus on public awareness and
473 education, and devise strategies to manage and control A. fulica‟s population. This in itself is quite a
Rhon Connor – MSc paper 18 474 major task, but proactive, practical and effective strategies must be implemented urgently. It‟s
475 important to note that both mechanical and chemical means of controlling this species have been
476 effective in the past, but they are associated with high costs. Certainly, whatever means of control the
477 authorities initiate, they must be cautioned against the introduction of biological controls or predatory
478 snails. This method has been associated with the extinction of many endemic snails in Hawaii and The
479 Society Islands. It should be noted however that the authorities in the island of Anguilla must now
480 review and upgrade existing legislation on the importation of goods entering the territory. The
481 introduction of strict quarantine measures must also be implemented and enforced to prevent other
482 forms of invasive species from entering the island.
483
484
485
Rhon Connor – MSc paper 19 486 Acknowledgements
487 I wish to thank my supervisor Dr. Tom Tregenza for his feedback and guidance with this project; to
488 my mentor Dr. Floyd Homer (Conservation Biodiversity Inc.) who provided valuable suggestions for
489 the manuscript. Special appreciation also goes to Farah Mukhida of the Anguilla National Trust who
490 willingly assisted with the data entry and offered suggestions for the study. Also thank you to Antonio
491 Christopher and William Vanterpool of the Department of Agriculture, Karim Hodge of the
492 Department of the Environment, Oliver Hodge of the Environmental Health Unit, and Guy Mathurin
493 (St. Lucia Ministry of Agriculture) for their resources and valuable information towards this project.
494 My appreciation is also extended to my wife Jackie Connor, Doyle Hughes, Asif Niles, and Alan Mills
495 for their contributions. I am particularly thankful to Dr. David Robinson (USDA APHIS) who
496 identified the snail species found in the study. A special thank you to all the respondents who willingly
497 took part in the survey, and most importantly my gratitude is extended to the Overseas Territories
498 Environmental Programme (OTEP) and the Government of Anguilla for their funding of my
499 studentship…for without them this project would not have been possible.
500
501
502
503
504
505
506
507
508
Rhon Connor – MSc paper 20 509 Literature Cited
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511 of Achatina Fulica Bowdich, 1822 (Mollusca: Gastropoda) as intermediate host of Angiostrongylus
512 costaricensis moreira and cespedes 1971. Brazilian Society for tropical Medicine. 36: 743-745
513
514 Civeyrel, L. and Simberloff, D. (1996) A tale of two snails: is the cure worse than the disease?
515 Biodiversity and Conservation 5: 1231-1252
516
517 Cowie, R.H. (1998) Patterns of introduction of non-indigenous non-marine snails and slugs in the
518 Hawaiian Islands. Biodiversity and Conservation 7 (3) 349-368
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520 Cowie, R. H and Robert P. Cook (1999). The Distribution and Abundance of Land Snails in the
521 National Park of American Samoa, with particular focus on partulidae. (Technical Report 125) page
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526 Craze, P. G. and Mauremootto, J.R.(2002) A test of methods for estimating population size of invasive
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529 Donlan, C.J., Tershy, B., Cambell, K., and Cruz, F. (2003) Diversity Research for Requiems: the need
530 for more collaborative action in eradication of invasive species. Conservation Biology 17 (6) 1850-
531 1851
532
533 Dowd, D., Greent, P., and Lake, P.S. (2003) Invasional „meltdown‟ on an oceanic island. Ecology
534 Letters 6, 812-817
535
Rhon Connor – MSc paper 21 536 Gabriel, A.G.A., Chown, S.L., Marshal, D.J., Mercer, R.D., Pugh, P.J.A., and Smith, V.R. (2001)
537 Biological Invasions of Southern Oceanic Islands: the Collembola of Marion Island as a test of
538 generalities. Ecography 24:421-430
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540 Gerlach, J. (2001) Predator, Prey and Pathogen interactions in introduced snail populations. Animal
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543 Gervin, V. (2005) Eco Defense against Invasions. Public Library of Science. 3 (12): 2066-2071
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545 Gurevitch, J. and Padilla, D. (2004) Are invasive species a major cause of extinctions? Trends in
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548 Kerans, B. L., Drydahl, M.F., Gangloff, M.M., and Jannot, J.E (2005) Potamophrgus anpodarum:
549 distribution, density and effects on native macroinvertebrate assemblages in the Greater Yellowstone
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561 Mead, A.R. and Palcy, L. (1992) Two giant African land snail species spread to Martinique, French
562 West Indies. The Veliger 35 (1) 74-77
563
Rhon Connor – MSc paper 22 564 Meyers, J. and Picot, F.(2001) Achatines Attack! The Impact of Giant African Land Snails on Rare
565 Endemic Plants in La Reunion Island (Mascarene Is., Indian Ocean). Aliens Newsletter. 14
566 (www.issg.org/aliens_newsletter/Aliens14.pdf). 15/04/06
567
568 Mooney, H.A. (2005) Invasive alien species: a new synthesis. Island Press. Washington, 3-12.
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570 Moses, K. and Ali, B. (2003) Invasive Species Threats in the Caribbean Region: Report to Nature
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573 Panigrahi A. and Raut, S. K (1994) Thevetia Peruviana (Family: Apocynaceae) in the control of slug
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575
576 Perring, C., et al. (2001) Biological Invasion Risks and Public Good: an Economic Perspective.
577 Conservation Ecology. 6 (1) [online] www.consecol.org/vol6/iss1/art1 (12/02/06).
578
579 Prasad, G.S. et al. (2004) Eco-friendly ways to keep away pestiferous giant African snail, Achatina
580 fulica Bowdich from nursery beds. Current Science 87 (12) 1657-1659
581
582 Raut, S. K. and Baker, G.M. (2002). Achatina Fulica Bowdich and other Achatinidae as pests in
583 Tropical Agriculture: in G. M. Barker (ed.) Mollusc as Crop Pests. CAB International. Oxford UK.
584 Page 55-61
585
586 Simberloff, D. (2003) How much information on population biology is needed to manage introduced
587 species? Conservation Biology 17 (1) 83-92
588
589 Simberloff, D. (1996). Impacts of introduced species of the United States. Consequences. 2:2
590
Rhon Connor – MSc paper 23 591 Simberloff D. and Gibbons L. (2004) Now you see them, now you don‟t!-population crashes of
592 established introduced species. Biological Invasions 6: 161-172
593
594 Singh, M.N. (1980) Occurrence of the giant African snail (Achatina fulica) in Bihar State. Journal of
595 Environmental Biology 7 (4) 253-257
596
597 Suarez A.V. , D. A. Holway and T.J. Case (2001) Patterns of spread in biological invasions dominated
598 by long-distance jump dispersal: Insights from Argentine ants. Proceedings of National Academy of
599 Science. 98 (3) 1095-1100
600
601 Thangavelu K and Singh K (1983) Giant African Snail Achatina Fulica Bowdich (Pulmonata:
602 Gastropod) as a serious pest of Mulberry from north-eastern region. Indian Journal of Agriculture
603 Science. 53 (9): 871-2
604
605 Tomiyama, K. and Nakane, M. (1993) Dispersal Patterns of the Giant African Snail, Achatina fulica
606 (Ferussac) (Stylommatophora: Achatinidae), Equipped with a Radio-Transmitter. Journal of
607 Molluscan Studies. 59:315-322
608
609 Upatham, E.S., Kruatrachue, M., and Baidikul, V.(1998) Cultivation of the Giant African Snail,
610 Achatina fulica. Scientific Society Journal of Thailand. 14:25-40
611
612 Vieiral, T. et al. (2004) Acharan Sulfate, the new glycosaminoglycan from Achatina Fulica Bowdich
613 1822 structural heterogeneity, metabolic labeling and localization in the body, mucus and the organic
614 shell matrix. European Journal of Biochemistry. 271, 845-854
615
616 Walker, M. M., Hodge, O., Homer, F., and Johnson, W. (2005) A Guide to Common Plants of
617 Anguilla. Anguilla National Trust.
618
Rhon Connor – MSc paper 24 619 With, K. (2002) The Landscape Ecology of invasive spread. Conservation Biology vol. 16 no.5 1192-
620 1203
621
622
623
624
625
626
627
628
629
Rhon Connor – MSc paper 25 630 Figure legends
631 Figure 1: Map showing the distribution of the Giant African Snails in Anguilla before and after
632 March 2006.
633
634 Figure 2: Density (per m2) of Live and Dead A. fulica at each survey site.
635
636 Figure 3: Mean Number (se) of live/dead snails per quadrat according to habitat type (N=40
637 quadrats per habitat type)
638
639 Figure 4: The number of live A.fulica according to micro habitat/physical location
640
641 Figure 5: Specimens of Anguillas terrestrial malacofauna.
642
643 Figure 6: Specimen of another invasive species of snail found in Anguilla.
644
645 Figure 7: Graphs showing respondents views in relation to A. fulica (Figures a-l)
646
647 Figure 8: Graphs showing the mean density (snails m-2) of dead snails from 40 (4m2
648 quadrats/habitats) in relation to its habitats within each village; and the mean density
649 of snails on wet and dry days.
650
651 Table 1: Table showing the villages and number of species of other snails from sampled sites.
652
653 Table 2: Density of Giant African Snails (based on all survey sites) compared to densities of
654 other snail species (also found within the survey sites).
655 Appendix 1 Giant African Snail Questionnaire 656 2 Hermit Crab using A. fulica shell 657 3 A. fulica shells collected by a resident 658
Rhon Connor – MSc paper 26 659 Figure 1 660 661
662 663 664
Rhon Connor – MSc paper 27 665 Figure 2 666
Density of Live and Dead GAS at each Survey Site
1.4
1.2
1 2 0.8 Live Dead
0.6 GASDensity m
0.4
0.2
0
South Hill George Hill Cauls Bottom Little Harbour Stoney Ground Survey Site 667 668 669
Rhon Connor – MSc paper 28 670 Figure 3 671
# of snails(live/dead)
14 12 10 Grass 8 shrubs 6 Woods 4 2 0
Mean (se) no. Mean of (se) snails per quadrat Little H. South H. Caul's B. George H. Stoney G. 672 673 674
Rhon Connor – MSc paper 29 675 Figure 4 676 677 a) On vegetation b) Under rocks and/or fallen wood 678
Live Snails on Vegetation Live Snails Under Rocks and/or Fallen Wood
160
140 40 120 35 100 30 25 80 20 60 15 No. of Live GAS of No. Live 40
No. of Live GAS of No. Live 10 20 5 0 0
South Hill South Hill George Hill George Hill Cauls Bottom Little Harbour Cauls Bottom Little Harbour Stoney Ground Stoney Ground Village Village 679 680 c) In leaf litter d) on tree trunks 681 682
Live Snails in Leaf Litter Live Snails on Tree Trunks
80 45 70 40 60 35 30 50 25 40 20 30
15
No. of Live GAS of No. Live No. of Live GAS of No. Live 20 10 10 5 0 0
South Hill South Hill George Hill George Hill Cauls Bottom Little Harbour Cauls Bottom Little Harbour Stoney Ground Stoney Ground Village Village 683 684 685 e) On rocks and/or stony ground. 686
Live Snails on Rocks and/or Stony Ground
40 35 30 25 20 15
No. of Live GAS of No. Live 10 5 0
South Hill George Hill Cauls Bottom Little Harbour Stoney Ground Village 687 688
Rhon Connor – MSc paper 30 689 Figure 5: 690 691 a); Drymaeus species- D. virgulatus b)Bulimulus guadalupensis (family Bulimulidae) 692 (family Bulimulidae) 693
694 695 696 697 c) Chondropoma (Chondropomorus) d) Macroceramus (family Urocoptidae) 698 (family Annulariidae/Licinidae;
699 700 701 702 e) Drymaeus Species- (family Bulimulidae) f) Species Subulinidae 703
704 705 706
Rhon Connor – MSc paper 31 707 708 Figure 6 709 710 Z. auricoma havenensis (family Pleurodontidae) 711
712 713 714
Rhon Connor – MSc paper 32 715 Figure 7 716 717 a b
Opinion of GAS Damage to Crops and/or Plants by GAS 2% 1% 12% 3% pest 1% 37% nuisance 44% Yes major/significant 42% No problem Don't know not a problem Not applicable no answer 42% No answer 16%
718 719 720 c d
GAS method of arrival Knowledge of Geographic Origin of the GAS 3% vehicles/containers 4% 6% 1% 16% on blocks/cement 1% imported plants 32% lumber Yes other No not applicable No answser 2% don’t know 44% 1% no answer
90% 721 722 723 e f
Year Learned About the GAS
Measures1% to Deal with the 100 GAS nothing 90 1% 80 2% 2% eradicate 70 1% 60 Respondents use chemicals to
% 50 control 40 30 export to countries for foood 20 37% 10 use locally as food 0 56% other
1999 2001 2003 2005 no answer No answer 724 Year 725 726 727 728 729 730 731 732 733
Rhon Connor – MSc paper 33 734 g h
Agencies Responsible for Baiting the Recognition of the GAS as a Disease Carrier 1% GAS 7% 10% 4% individuals affected Department 35% of Agriculture 46% yes special task no force don't know other 47% 50% no answer 735 736 737 i j
Willingness to Participate in an Willing to Pay for Eradication Programme Eradiction of the GAS 6% 3% 14% 16%
yes yes no no don't know don't know
78% 83% 738 739 k l
Agency responsible for eradicating GAS Respondent GAS control measures
2% 6% 1% 14% Agricultural 13% Household bait 1% Department Snail bait Residents/community 0% 11% Crush Government 50% Hotwater 15% Other All stakeholders Not applicable No answer No answer 72% 15% 740 741
Rhon Connor – MSc paper 34 742 Figure 8 743 744 a) b)
Mean Density (se) snails in Woodland Habitat Mean (se) Density of Snails in Shrubland Habitat
5 7 4.5 6.5 6 4 5.5 3.5 5 4.5 3 Live 4 Live 2.5 3.5 Dead Dead 2 3
2.5 quadrat(N=40) quadrat(N=40) 1.5 2 1 1.5 1
0.5 0.5 meandensity per (se)# snails 0 Density (se) Mean of per snails 0 Caul's Stoney George Little South Caul's Stoney George Little South Bottom Ground Hill Harbour Hill Bottom Ground Hill Harbour Hill Village Village 745 746 c) d)
Mean (se) Density of Snails in Grassland Mean (se) # of snails found on wet and dry days in habitats each village
4 10 9 3.5 8 3 7 2.5 6 Live 2 WET 5 4 Dead 1.5 Dry
3 1
quadrat(N=40) (se) snails Mean # 2 0.5 1 0 0
Mean Density (se) Mean of per snails Caul's Stoney George Little South Hill Cauls Stoney George Little South Hill Bottom ground Hill Harbour bottom Ground Hill Harbour Village Village 747
Rhon Connor – MSc paper 35 748 Table 1: 749 Cauls Stoney Little Species George Hill South Hill Bottom Ground Harbour Drymaeus species- D. 304 1284 1204 1097 209 virgulatus (family Bulimulidae)
Bulimulus 2 0 55 54 3 guadalupensis (family Bulimulidae)
Chondropoma 107 67 264 400 67 (Chondropomorus) Family annulariidae/Licinidae
Macroceramus 0 0 47 171 0 (family Urocoptidae)
Drymaeus Species- 0 0 0 11 0 (family Bulimulidae) (striped)
Species Subulinidae 0 0 0 3 0
Total individuals 413 1351 1570 1736 288
Total species 3 2 4 6 3 750 751
Rhon Connor – MSc paper 36 752 Table 2
Snail Species Density Drymaeus species- D. virgulatus (family 1.708 Bulimulidae)
Bulimulus guadalupensis (family Bulimulidae) 0.0475
Chondropoma (Chondropomorus) Family 0.381 annulariidae/Licinidae
Macroceramus (family Urocoptidae) 0.091
Drymaeus Species- (family Bulimulidae) 0.00458 (striped)
Species Subulinidae 0.00125
Giant African Snail 1.0575 753
754
Rhon Connor – MSc paper 37 755 Appendix 1
756 Giant African Snail Questionnaire
757 758 Village ______
759
760 Gender: Male ___ Female ___
761
762 Age group: 18-25; 26-40: 41-55: 56-70: 70+
763
764 How long have you lived in this area?
765 Less than one year, 1-2 years 3-4 years Over 4 years
766
767 Are there Giant African Snails (GAS) within 100 m of this area? Y / N (if no Q 4)
768
769 Do you find GAS in your yard? Yes / No (if yes Q 5 )
770
771 Are you worried that the GAS will invade your premises? Yes / No (skip 5 go to 6)
772
773 Approx. how many do you find in your yard at any given time (with dew / rain)?
774 Less than 50 50 – 100 100-150 150-200 over 200
775
776 Do you think that the population of GAS is Increasing or decreasing?
777
778 Which of the following best describes your opinion of the GAS?
779 A pest a nuisance a major/significant problem its not a problem
780
Rhon Connor – MSc paper 38 781 If the GAS has caused you financial losses, which of the following estimates (USD)best describes
782 your loss within the past year?
783 under $50 50-100 100-150 150-200 over 200
784
785 What measures do you take to control it?
786 Household salt snail bait crush them use of hot water other
787
788 Does the GAS cause significant damage to your crops/plants? Yes / No / Don‟t know
789
790 What type of plants are mostly affected? Horticultural / Agricultural /Both
791
792 Do you know the geographic origin of the snails? Yes / No
793
794 How did you first learn of the invasion of the GAS?
795 Agricultural Dept. Anguilla Nat‟t Trust Family/friend other
796
797 Around what year you first heard of these snails in Anguilla?
798 ‟99 ‟01 ‟02 ‟03 ‟04 ‟05 06
799
800 Do you think that they (GAS) were intentionally brought to Anguilla? Yes / No / don‟t know (don‟t
801 know Q17)
802 If yes, for what purpose? Food, Pets, Attractions, other
803 If no, which of these methods mostly assist in their arrival?
804 attached to vehicles/containers; on blocks/cement; imported plants, lumber, other
805
806 What measures do you think should be taken to deal with the GAS?
807 Nothing (allow them to remain in isle): eradicate them; use chemicals to control them: export them to
808 countries (food): use them as source of food (locally).
Rhon Connor – MSc paper 39 809
810 Have you seen them in other neighbouring islands? Yes / No
811
812 Have your area been treated (baited) by the Agriculture department? Yes / No / Don‟t know
813
814 Do you believe that the chemical is effective? Yes No Don‟t Know
815
816 Do you believe that the authorities are doing enough to educate the public about the GAS? Yes / No /
817 Don‟t know
818
819 Do you believe that the authorities are doing enough to educate the public about the GAS? Yes / No /
820 Don‟t know
821
822 Were you given clear guidelines about how to handle the GAS ? Yes / No
823
824 Who do you believe is responsible for the baiting of snails?
825 Individuals affected; Agri. Department; Special task force other
826
827 Who is responsible for the eradication of these snails?
828 Agri. Dept. Residents/Community Government All Stakeholders
829
830 Which of these measures do you believe is the most effective in controlling the GAS?
831 Handpicking and destroying using cooking salt use of snail bait other methods
832
833 Which of the following agencies have you reported sightings of the GAS?
834 Agri. Dept. Env. Dept. Anguilla National Trust None (did not report it)
835
836 Do you know the GAS can carry a potentially serious human disease?
Rhon Connor – MSc paper 40 837 Yes / No / Don‟t Know
838
839 Will you be willing to participate in an eradication programme? Yes / No / Don‟t Know
840
841 Will you be willing to pay a fee towards the eradiction of the GAS? Yes/No/Don‟t Know
842
Rhon Connor – MSc paper 41