Article

From 61 species to five: Endemic tree snails of the Society Islands fall prey to an ill-judged biological control programme

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Abstract

Following the well documented extinctions of many species of endemic tree snail (family Partulidae) throughout French Polynesia, field surveys were undertaken on four islands in the Society archipelago to provide up to date information for the international conservation programme for this group of invertebrates. These surveys have confirmed the loss of all species of Partula in the wild on the Society Islands other than Tahiti. Thirty-three species have been lost from Raiatea, thereby eliminating one of the most outstanding examples of island evolutionary radiation. On Huahine the disappearance of P. varia and P. rosea, used for making lei (shell jewellery), had an economic and social effect on the local community: many of the women of the villages lost their livelihoods, and the artisan's association folded. The seven species of Partula on Moorea were extinct in the wild by the mid 1980s, terminating almost 100 years of biological research. It now seems that the remnant populations of Samoana attenuata discovered only 5 years ago are the only species of partulid still surviving beyond Tahiti on the Society Island group. The mixed species populations in the Te Pari area of Tahiti-Iti are still extant, but the predatory snail Euglandina rosea has now spread to the last valley on the Peninsula that did not have previous evidence of predator activity. On Tahiti-Nui populations of partulid, without the predator, were found near the crest of Mount Tahiti above Orofero Valley. Partulidae are clearly a highly threatened family of invertebrates, and in need of the most intense conservation focus.

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... Euglandina rosea was released on Tahiti in 1974, Moorea in 1977, and on other Society Islands from 1980 to 1990s (Coote, 2007). Approximately 51% (N = 28/55 species) of Society Island partulid species are now considered extinct (Coote & Loève, 2003;Gerlach, 2016), with 96% (27/28 spp.) of those representing taxa from the genus Partula (N = 27/51 spp.). A subset of Partula tree snails collectively persists in captivity (N = 13 spp.; Figure 1a; ...
... Estimates of the number of Society Island endemic Partula species and of their survival have been in considerable flux complicating the conservation status of this critically endangered archipelagic radiation. For instance, one study (Coote & Loève, 2003) recorded 16/58 species surviving, with all 16 surviving in captivity and five of those also surviving in the wild, whereas a more recent taxonomic revision (Gerlach, 2016) respectively listed a total of 18/51 surviving, with five surviving in the wild, three in the wild and in captivity, and 10 in captivity. A persistent issue has been the extensive lack of congruence among taxonomy, morphology, different molecular markers, and degree of reproductive isolation among the species (Clarke, Johnson, Murray, Hewitt, & Wragg, 1996;Gerlach, 2016;Haponski, Lee, & Ó Foighil, 2017;Johnson, Murray, & Clarke, 1986a;Lee, Li, Churchill, & Ó Foighil, 2014;Murray, Stine, & Johnson, 1991), especially for the much better studied species on the Windward Islands of Moorea and Tahiti. ...
... Samoana survive on Moorea and Tahiti (Lee et al., 2009). Combined with our evidence of five surviving genomic Partula species complexes, it appears that the loss of phylogenetically discrete endemic Moorean and Tahitian partulid species has been less than originally feared (Clarke et al., 1984;Coote & Loève, 2003). However, these results for the Windward Islands do not address the losses of Partula species on the other Society islands. ...
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Eleven of eighteen Society Island Partula species endemic to the Windward Island subgroup (Moorea and Tahiti) have been extirpated by an ill‐advised biological control program. The conservation status of this critically endangered tree snail radiation is of considerable import, but is clouded by taxonomic uncertainty due to the extensive lack of congruence among species designations, diagnostic morphologies and molecular markers. Using a combination of museum, captive, and remnant wild snails, we obtained the first high‐resolution nuclear genomic perspective of the evolutionary relationships and survival of fourteen Windward Island Partula species, totaling 93 specimens. We analyzed ~1,607‐28,194 nuclear genomic loci collected with the double digest Restriction‐site Associated sequencing method. Results from phylogenomic trees, species estimation, and population assignment tests yielded monophyly of the Windward Island subgroup. Within this group, two well‐supported clades encompassing five species complexes were recovered. Clade 1 was restricted to Tahiti and contained two species complexes: “P. affinis” (three species) and “P. otaheitana” (five species). Clade 2 occurred on Moorea and on Tahiti and consisted of three species complexes: one Tahitian, “P. clara/P. hyalina”; the other two, “P. taeniata” (three species) and “P. suturalis” (six species), Moorean. Our genomic results largely corroborated previous mitochondrial DNA survival estimates for Moorea and Tahiti, with all five species complexes having members surviving in captivity and/or as remnant wild populations, although the details vary in each case. Continued, proactive conservation and management may yet ensure a phylogenetically‐representative survival of the fabled Partula species of Moorea and Tahiti. This article is protected by copyright. All rights reserved.
... A significant fraction of that total involves the endemic Pacific Island land snail family Partulidae: an estimated 32-39% of 104 species are now considered extinct, another 9% are extinct in the wild and 50% are classified as threatened (Gerlach, 2016). Much of that loss occurred in the Society Islands following the deliberate release of E. rosea on Tahiti in 1974, on Moorea in 1977, and on other Society Islands in the 1980s and 1990s (Murray et al., 1988;Coote & Loève, 2003). Another snail predator, the New Guinea flatworm Platydemus manokwari (De Beauchamp, 1962), is now also present in the Society Islands and is probably responsible for the extirpation of populations of E. rosea in addition to some populations of surviving endemic partulids (Justine et al., 2015;Gerlach, 2016). ...
... Although this species still survives in Tahitian cloud forests > 1000 m in elevation (Lee et al., 2007), clutch size data for these enduring montane populations are not presently available. The surviving population of Tahitian endemic P. affinis detected by Coote & Loève (2003) is now extirpated and the last sighting of this species in the wild was a single specimen in 2013 (T. Coote, pers. ...
... The other is the intermediate mean ICS exhibited by P. taeniata, the only Moorean Partula species that has withstood (if only barely) four decades of predation by E. rosea (Lee et al., 2009) and at least 8 years of predation by the invasive New Guinea flatworm Platydemus manokwari (Justine et al., 2015). Although P. suturalis vexillium and P. aurantia had overlapping distributions with, and higher ICS than, P. taeniata, both of them have been extirpated (Coote & Loève, 2003), as have the two Moorean partulids with the highest mean ICS, P. aurantia and P. s. vexillum (Fig. 3). In contrast, the sole surviving Moorean species, P. taeniata, had an intermediate clutch size, ranked third highest (Fig. 3). ...
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Endemic Pacific Island land snails are among the planet's most endangered taxonomic groups and many have fallen victim to misguided biological control programmes involving the rosy wolf snail, Euglandina rosea. The family Partulidae has been heavily impacted but a recent study of Tahitian species found that survivors had differentially higher clutch sizes. Here, we further tested the inference that higher fecundities may promote survival of Partula species by incorporating historical field demographic data from additional island populations (Guam, Saipan and Moorea) that collectively span the range of the family, as well as complementary demographic data from captive populations sourced from these islands and from Tahiti. Our primary result broadly corroborated the earlier study: species with higher reproductive output, whether measured by historical field clutch sizes or by reproductive rates in captivity, are more likely to have survived. However, this generality does not apply to all island populations and it is unlikely to be the sole determining factor in any of these cases. Detailed ecological and behavioural studies of extant wild P. radiolata (Guam), P. gibba (Guam and Saipan), P. taeniata (Moorea), P. hyalina and P. clara (Tahiti) populations, and of their co-occurring introduced predators, are urgently required.
... A significant fraction of that total involves the endemic Pacific Island land snail family Partulidae: an estimated 32-39% of 104 species are now considered extinct, another 9% are extinct in the wild and 50% are classified as threatened (Gerlach, 2016). Much of that loss occurred in the Society Islands following the deliberate release of E. rosea on Tahiti in 1974, on Moorea in 1977, and on other Society Islands in the 1980s and 1990s (Murray et al., 1988;Coote & Loève, 2003). Another snail predator, the New Guinea flatworm Platydemus manokwari (De Beauchamp, 1962), is now also present in the Society Islands and is probably responsible for the extirpation of populations of E. rosea in addition to some populations of surviving endemic partulids (Justine et al., 2015;Gerlach, 2016). ...
... Although this species still survives in Tahitian cloud forests > 1000 m in elevation (Lee et al., 2007), clutch size data for these enduring montane populations are not presently available. The surviving population of Tahitian endemic P. affinis detected by Coote & Loève (2003) is now extirpated and the last sighting of this species in the wild was a single specimen in 2013 (T. Coote, pers. ...
... The other is the intermediate mean ICS exhibited by P. taeniata, the only Moorean Partula species that has withstood (if only barely) four decades of predation by E. rosea (Lee et al., 2009) and at least 8 years of predation by the invasive New Guinea flatworm Platydemus manokwari (Justine et al., 2015). Although P. suturalis vexillium and P. aurantia had overlapping distributions with, and higher ICS than, P. taeniata, both of them have been extirpated (Coote & Loève, 2003), as have the two Moorean partulids with the highest mean ICS, P. aurantia and P. s. vexillum (Fig. 3). In contrast, the sole surviving Moorean species, P. taeniata, had an intermediate clutch size, ranked third highest (Fig. 3). ...
Article
Full-text available
Endemic Pacific Island land snails are among the planet's most endangered taxonomic groups and many have fallen victim to misguided biological control programmes involving the rosy wolf snail, Euglandina rosea. The family Partulidae has been heavily impacted but a recent study of Tahitian species found that survivors had differentially higher clutch sizes. Here, we further tested the inference that higher fecundities may promote survival of Partula species by incorporating historical field demographic data from additional island populations (Guam, Saipan and Moorea) that collectively span the range of the family, as well as complementary demographic data from captive populations sourced from these islands and from Tahiti. Our primary result broadly corroborated the earlier study: species with higher reproductive output, whether measured by historical field clutch sizes or by reproductive rates in captivity, are more likely to have survived. However, this generality does not apply to all island populations and it is unlikely to be the sole determining factor in any of these cases. Detailed ecological and behavioural studies of extant wild P. radiolata (Guam), P. gibba (Guam and Saipan), P. taeniata (Moorea), P. hyalina and P. clara (Tahiti) populations, and of their co-occurring introduced predators, are urgently required.
... For other well-known invasive gastropod species, such as the rosy wolf snail E. rosea, common garden snail Cornu aspersum and the New Zealand mud snail Potamopyrgus antipodarum, reported costs were few or even completely lacking, despite their almost global invasion histories (Cowie, 2000;Roll et al., 2009;Sanderson and Sirgel, 2002). Euglandina rosea has been found to cause a dramatic decline and even the extinction of many native gastropod species, particularly on many pacific islands (Coote and Loeve, 2003;Cowie, 2000). For this reason, it is listed among the 100 of the world's worst invasive species (Lowe et al., 2000;Luque et al., 2014). ...
... For this reason, it is listed among the 100 of the world's worst invasive species (Lowe et al., 2000;Luque et al., 2014). Recently it was suggested that its invasion had caused economic and social losses to local communities on the Society Islands, as many local women lost their livelihoods when the endemic snails they had used in order to produce shell jewelry had disappeared (Coote and Loeve, 2003). However, estimating the economic losses of such diversity losses is still very difficult, as non-market effects are usually associated with ecosystem degradation (Kouba et al., 2022). ...
Article
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Invasive alien gastropods are a particularly pervasive taxonomic group worldwide, often causing substantial impacts on aquatic and terrestrial ecosystems. Yet, much remains unknown about this invasive group’s economic costs to human society. Here, we used the InvaCost database to evaluate the taxonomic, spatial, and temporal patterns of economic costs associated with invasive gastropods on the global scale. In total, 13 species of invasive gastropods caused a cumulative global cost of US3.94billionovertheperiod19662020,withamajoritybeingattributedtoaquaticspecies( 3.94 billion over the period 1966–2020, with a majority being attributed to aquatic species ( 3.72 billion, 94.4 %, concentrated mostly in Asia) and only $ 0.22 billion (5.6 %, concentrated mostly in Europe) to terrestrial species. Among different regions, Asia (3.71 billion) reported the greatest costs, compared to far lower costs reported in Europe (214.50 million), North America (13.80 million), Oceania (2.69 million), South America (
... The clearest evidence of a direct impact was that as E. rosea spread across the island of Moorea, the endemic Partula tree snail species vanished in its wake; it did not control A. fulica (Murray et al., 1988;Cowie, 2001). On the other islands of the Society group the same story played out (Coote and Loè ve, 2003;. ...
... This rate (5% per decade) is much higher than the global estimate of the loss over the last 500 years or so of 3,000-5,100 (10-17%) of the 30,000 known land snail species, as estimated by Ré gnier et al. (2015a) and outlined above. The amastrids, however, may be an extreme case, although land snail groups from other Pacific islands have suffered similar fates, notably the Endodontidae (Solem, 1976;Zimmerman et al., 2009;Sartori et al., 2013; and Partulidae (Coote et al., 2003;, and many extinct species continue to be found, as empty shells, even before their scientific description (e.g., Richling and Bouchet, 2013). Oceanic island biotas are in general much more susceptible to extinction than more buffered continental faunas (Triantis et al., 2010). ...
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The International Union for Conservation of Nature (IUCN) is the premier global biodiversity conservation organization. Its Red List is a rigorous vehicle for assessing the conservation status of plant and animal species. However, although all animal and bird species recognized by IUCN have been evaluated , only a tiny fraction of invertebrates have been evaluated. As a measure of the numbers of extinct species (since around the year 1500) the Red List is probably quite accurate for birds and mammals, but severely underestimates the numbers for invertebrates. Nonetheless, molluscs stand out as the major group most severely impacted by extinction, with 297 of the 744 animal species listed as extinct in the third issue of the 2016 Red List. Here we review efforts to obtain a more realistic , albeit less rigorous, assessment of the numbers of extinct mollusk species. Our approach has been based on biblio-graphic research and consultation with experts, rather than following the highly detailed but restrictive IUCN Categories and Criteria. In 2009, this led to an assessment that 533 mol-lusk species were extinct, far more than the number on the Red List. In the present study we revisited this approach and here list 638 species as extinct, 380 as possibly extinct, and 14 as extinct in the wild, a total of 1,032 species in these combined categories, and more than twice as many as listed by IUCN in these categories. However, this approach only considers species for which information is available; it is therefore biased. In a study published in 2015 we developed an alternative approach, based on a random global sample of land snails, and estimated that 3,000–5,100 mollusk species have gone extinct. We review the main reasons for these extinctions: habitat destruction, impacts of introduced species, exploitation and collecting, and, potentially, climate change, and discuss relevant case studies.
... Among the most publicized biological control cases gone awry is the introduction of the predatory land snail Euglandina rosea (Férrusac, 1821) from Florida to Hawaii to control the giant African snail, Lissachatina fulica (Bowdich, 1822) (Davis and Butler 1964;Civeyrel and Simberloff 1996;Stone 1999;Cowie 2001a). Not only did E. rosea fail to reduce L. fulica populations (Civeyrel and Simberloff 1996;Cowie 2001a), it has been implicated as a major factor in the decline and extinction of native land snails in Hawaii and islands throughout the tropics and subtropics (e.g., Pacific, Indian and Atlantic Ocean Islands), where it was subsequently introduced (Murray et al. 1988;Hadfield et al. 1993;Gerlach 1999;Civeyrel and Simberloff 1996;Bieler and Slapcinsky 2000;Coote and Loève 2003). For example, the native Hawaiian land snail fauna, which contains no native predatory species, used to be extraordinarily diverse (750? ...
... species) with extremely high endemism (over 99%) (Cowie et al. 1995), but estimates of extinction of these unique species range from 65 to 90% (Solem 1990;Cowie 2001b;Lydeard et al. 2004;Régnier et al. 2015). Extinction rates of endemic land snail fauna on other tropical islands have been equally significant and E. rosea has been identified as a significant contributing factor to the loss (Murray et al. 1988;Civeyrel and Simberloff 1996;Coote and Loève 2003;Bick et al. 2016). ...
Article
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The introduction of the predatory land snail, Euglandina rosea (Férrusac, 1821) from Florida to Hawaii to control the giant African snail, Lissachatina fulica (Bowdich, 1822) is among the most publicized biological control cases gone awry. Following preliminary genetic analyses that revealed a second, possibly undescribed Euglandina species was probably introduced to Hawaii, we used an integrative systematic approach combining both genetic and morphological assessments to examine the taxonomic status of the snail referred to as E. rosea in Hawaii. Genetic and morphological analyses support the interpretation that two Euglandina species were introduced to and have become established in Hawaii and can be readily distinguished based on morphological differences. This finding has significant ramifications for understanding both historical and contemporary biocontrol as it suggests that: (1) other species may have been inadvertently introduced through bio-control programs, (2) inadequate understanding of the taxonomy of bio-control agents has obscured our ability to effectively study their ecological impacts, and (3) while the US has no comprehensive regulatory framework for importing biological control agents, one is urgently needed. This also has wide-ranging implications for conservation efforts throughout the tropics because Euglandina from Oahu, Hawaii were released on other Hawaiian Islands, New Guinea, Okinawa, Palau Islands, Philippines, India, Bonin Islands and Bermuda for use in biological control programs that led to catastrophic loss of endemic land snail diversity.
... The clearest evidence of direct impact was that as E. rosea spread across the island of Moorea, the endemic Partula tree snail species vanished in its wake (though a few remnant populations were subsequently discovered and represent most of the major genetic lineages; Haponski et al., 2019); it did not control A. fulica (Murray et al., 1988;Chiba and Cowie, 2016). On the other islands of the Society group the same story played out, with the exception of a few remnant populations surviving on Tahiti in addition to those on Moorea (Coote and Loève, 2003;Gerlach, 2016). As currently recognised (Gerlach, 2016), of 18 Moorean and Tahitian species, 6 are Extinct, 5 are Extinct in the Wild, 4 are represented by remnant wild individuals and 3 by both captive and remnant wild individuals (Haponski et al., 2019). ...
Chapter
Since 1970, there has been an overall decline in wildlife populations in the order of 52%. Freshwater species populations have declined by 76%; species populations in Central and South America have declined by 83%; and in the Indo-Pacific by 67%. These are often not complete extinctions, but large declines in the numbers of animals in each species, as well as habitat loss. This presents us with a tremendous opportunity, before it is too late to rescue many species. This book documents the present state of wildlife on a global scale, using a taxonomic approach, and serving as a one stop place for people involved in conservation to be able to find out what is in decline, and the success stories that have occurred to bring back species from the brink of extinction - primarily due to conservation management techniques - as models for what we might achieve in the future.
... Therefore, biological invasions can have a devastating effect on island biodiversity (2). For example, the introduction of a predatory snail to biologically control the invasive giant African snail has exterminated most endemic tree snail species in French Polynesia (3). Bird species endemic to islands are more prone to extinction than continental species, which is largely due to the detrimental effects of mammalian predators such as rats, cats, and pigs, among others (4). ...
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On volcanic islands, the release of animals from predators and competitors can lead to increased body size and population density as well as the expanded habitat use of introduced animals relative to their mainland counterparts. Such alterations might facilitate the spread of diseases on islands when these exotic animals also carry pathogenic agents; however, this has rarely been investigated. The commensal Asian house rat (Rattus tanezumi) is confined to human residential surroundings in mainland Taiwan but can be observed in the forests of nearby Orchid Island, which is a tropical volcanic island. Orchid Island is also a hot spot for scrub typhus, a lethal febrile disease transmitted by larval trombiculid mites (chiggers) that are infected primarily with the rickettsia Orientia tsutsugamushi (OT). We predicted an increase in chigger abundance when rodents (the primary host of chiggers) invade forests from human settlements since soils are largely absent in the latter habitat but necessary for the survival of nymphal and adult mites. A trimonthly rodent survey at 10 sites in three habitats (human residential, grassland, and forest) found only R. tanezumi and showed more R. tanezumi and chiggers in forests than in human residential sites. There was a positive association between rodent and chigger abundance, as well as between rodent body weight and chigger load. Lastly, >95% of chiggers were Leptotrombidium deliense and their OT infection rates were similar among all habitats. Our study demonstrated potentially elevated risks of scrub typhus when this commensal rat species is allowed to invade natural habitats on islands. Additionally, while the success of invasive species can be ascribed to their parasites being left behind, island invaders might instead obtain more parasites if the parasite requires only a single host (e.g., trombiculid mite), is a host generalist (e.g., L. deliense), and is transferred from unsuitable to suitable habitats (i.e., human settlements on the mainland to forests on an island).
... Post-European-contact extinctions include several Mascarene Cylindraspis tortoises, the Mauritius dodo (Raphus cucullatus), the Rodrigues solitaire (Pezophaps solitaria), the Réunion ibis (Threskiornis solitarius) (Cheke and Hume, 2008), the Commander Islands (Steller's) sea cow (Hydrodamalis gigas) (Anderson, 1995), roughly 30 species of Partula snails endemic to Society Islands (Coote and Loéve, 2003), several St. Helena arboreal sunflowers (Asteraceae) (Cronk, 1989) and more recently the Canarian black oystercatcher (Haemotopus meadewaldoi) (Valledor de Lozoya, 2013), the Cabo Verde giant skink (Chioninia coctei) (Rocha et al., 2015) and the Tasmanian thylacine (Thylacinus cynocephalus) (Paddle, 2002), just to mention some of the more spectacular cases. Bird extinctions in the Hawaiian Islands have continued into the 21st century (Hume, 2017). ...
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Despite islands contributing only 6.7% of land surface area, they harbor ~20% of the Earth’s biodiversity, but unfortunately also ~50% of the threatened species and 75% of the known extinctions since the European expansion around the globe. Due to their geological and geographic history and characteristics, islands act simultaneously as cradles of evolutionary diversity and museums of formerly widespread lineages – elements that permit islands to achieve an outstanding endemicity. Nevertheless, the majority of these endemic species are inherently vulnerable due to genetic and demographic factors linked with the way islands are colonized. Here, we stress the great variation of islands in their physical geography (area, isolation, altitude, latitude) and history (age, human colonization, human density). We provide examples of some of the most species rich and iconic insular radiations. Next, we analyze the natural vulnerability of the insular biota, linked to genetic and demographic factors as a result of founder events as well as the typically small population sizes of many island species. We note that, whereas evolution toward island syndromes (including size shifts, derived insular woodiness, altered dispersal ability, loss of defense traits, reduction in clutch size) might have improved the ability of species to thrive under natural conditions on islands, it has simultaneously made island biota disproportionately vulnerable to anthropogenic pressures such as habitat loss, overexploitation, invasive species, and climate change. This has led to the documented extinction of at least 800 insular species in the past 500 years, in addition to the many that had already gone extinct following the arrival of first human colonists on islands in prehistoric times. Finally, we summarize current scientific knowledge on the ongoing biodiversity loss on islands worldwide and express our serious concern that the current trajectory will continue to decimate the unique and irreplaceable natural heritage of the world’s islands. We conclude that drastic actions are urgently needed to bend the curve of the alarming rates of island biodiversity loss.
... The tree snail family Partulidae, with species endemic to many Pacific Islands and archipelagos, has been the focus of population and evolutionary studies since the 19th century, principally in the Society Islands of French Polynesia (Garrett, 1880(Garrett, , 1884Crampton, 1916Crampton, , 1932Johnson et al., 1993a). Following mass extinctions beginning in the 1970s due to the introduction of the carnivorous snail Euglandina rosea in a failed biological control attempt, attention immediately switched to conservation science Cowie, 1992;Coote & Loève, 2003). Researchers working in the field began collecting snails and placing them in universities and zoos in Europe and North America to prevent their certain extinction. ...
... While failing to control L. fulica [7,8,12,17,[33][34][35], Euglandina spp. have been recorded as probably the main cause of numerous endemic land snail extinctions, especially in the Hawaiian Islands and French Polynesia [11,12,33,[36][37][38][39][40][41][42][43][44][45] as well as Bermuda [46][47][48][49] and the islands of Mauritius and Rodrigues in the Indian Ocean [50]. ...
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Classic biological control of pest non-marine mollusks has a long history of disastrous outcomes, and despite claims to the contrary, few advances have been made to ensure that contemporary biocontrol efforts targeting mollusks are safe and effective. For more than half a century, malacologists have warned of the dangers in applying practices developed in the field of insect biological control, where biocontrol agents are often highly host-specific, to the use of generalist predators and parasites against non-marine mollusk pests. Unfortunately, many of the lessons that should have been learned from these failed biocontrol programs have not been rigorously applied to contemporary efforts. Here, we briefly review the failures of past non-marine mollusk biocontrol efforts in the Pacific islands and their adverse environmental impacts that continue to reverberate across ecosystems. We highlight the fact that none of these past programs has ever been demonstrated to be effective against targeted species, and at least two (the snails Euglandina spp. and the flatworm Platydemus manokwari) are implicated in the extinction of hundreds of snail species endemic to Pacific islands. We also highlight other recent efforts, including the proposed use of sarcophagid flies and nematodes in the genus Phasmarhabditis, that clearly illustrate the false claims that past bad practices are not being repeated. We are not making the claim that biocontrol programs can never be safe and effective. Instead, we hope that in highlighting the need for robust controls, clear and measurable definitions of success, and a broader understanding of ecosystem level interactions within a rigorous scientific framework are all necessary before claims of success can be made by biocontrol advocates. Without such amendments to contemporary biocontrol programs, it will be impossible to avoid repeating the failures of non-marine mollusk biocontrol programs to date.
... Human agency has been their primary extinction driver, mainly through the introduction of snail predators, e.g., the North American rosy wolf snail, Euglandina rosea 4,5 . This predator has been implicated in the extinction of at least 134 snail species 2 , many of them members of the scientifically prominent [6][7][8][9] Society Island Partula species radiation [10][11][12] . Although this radiation is now largely extinct, a few representatives still persist in the wild either in montane refuges or as relictual valley populations [12][13][14][15] . ...
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Pacific Island land snails are highly endangered due in part to misguided biological control programs employing the alien predator Euglandina rosea . Its victims include the fabled Society Island partulid tree snail fauna, but a few members have avoided extirpation in the wild, including the distinctly white-shelled Partula hyalina . High albedo shell coloration can facilitate land snail survival in open, sunlit environments and we hypothesized that P. hyalina has a solar refuge from the predator. We developed a 2.2 × 4.8 × 2.4 mm smart solar sensor to test this hypothesis and found that extant P. hyalina populations on Tahiti are restricted to forest edge habitats, where they are routinely exposed to significantly higher solar radiation levels than those endured by the predator. Long-term survival of this species on Tahiti may require proactive conservation of its forest edge solar refugia and our study demonstrates the utility of miniaturized smart sensors in invertebrate ecology and conservation.
... Incidentally, E. rosea did not control L. fulica. On the other islands of the Society group the same story played out (Coote and Loève, 2003). In Hawaii, the combination of E. rosea and invasive rats, following on from habitat destruction, has caused the decline and extinction of endemic achatinelline tree snails, and another introduced predatory snail, Oxychilus alliarius, may yet impact endemic Hawaiian species, notably the single species in the endemic genus Kaala (Curry et al., 2016). ...
Chapter
At least 4000 land snail species are known from the islands of the tropical and subtropical Pacific, and if New Guinea and New Zealand are included, the number is probably closer to 6000. Most of these species are single island or at least single archipelago endemics. The geographic origins of most lineages of these island land snails can be traced to Asia and Australasia. Rafting on terrestrial debris, transport by birds and being blown on the wind have all been suggested as mechanisms by which the first individuals dispersed from these regions to the oceanic islands of the central Pacific, most of which have never been connected to a continental land mass. The extraordinary numbers of species on many islands then arose via evolutionary diversification in situ. Much of the fauna, however, is now extinct, as a result of habitat destruction and predation by introduced invasive species. Yet there remain many species still to be discovered, although many of these will also already be extinct, only their shells remaining as records of past diversity. Conservation of the remaining living species of this immensely diverse fauna has focused primarily on some of the larger and more attractive species, notably the achatinelline tree snails in Hawaii, the partulid tree snails in French Polynesia, and the radiation of species of Mandarina in the Ogasawara Islands. Efforts have involved building small scale, predator-free reserves (exclosures) with suitable habitat in which snails are protected, and ex situ captive breeding to preserve species in the hope of their eventual release back into the wild. However, the prognosis is not good, and to understand fully the immense diversity of Pacific island land snails will yet require intensive and extensive survey work so that those species, as yet undiscovered but that will be lost from the wild, can at least be collected and preserved in museums for future generations to study and marvel at.
... The four orthurethran families Achatinellidae, Amastridae, Draparnaudiidae and Partulidae are endemic to the islands of the Pacific. Many of these Pacific species have narrow distributional ranges and are under severe threat from habitat destruction and introduced predators; amastrids, which are endemic to Hawaii, have almost all become extinct, and the loss of numerous achatinellid and partulid taxa has been well documented (see: Cowie, 1992;Coote & Loeve, 2003;Holland & Hadfield, 2004;Régnier et al., 2015). ...
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We have undertaken a molecular analysis of the Orthurethra, one of the major groups of stylommatophoran land snails and slugs. Approximately 4000 nucleotides of the rRNA gene cluster [5.8S, internal transcribed spacer 2 (ITS2) and almost the full-length large subunit (LSU; 28S) gene] were sequenced for 40 orthurethran genera belonging to 19 families. Our phylogeny recovers three well-supported clades within the Orthurethra; the Azecidae, Chondrinidae + Truncatellinidae, and a main clade comprising all remaining orthurethran families. The first division in the Orthurethra separates the Azecidae from all other orthurethran taxa. Of those families represented by more than one genus, the Achatinellidae, Azecidae, Cerastidae, Partulidae and Vertiginidae are recovered as strongly supported monophyletic units, whereas the Chondrinidae, Enidae, Pupillidae and Valloniidae are unsupported in the tree. Although there is relatively little support for the deep-level relationships among the main orthurethran groups, some groupings are strongly supported. The sister-group relationship of the Cochlicopidae with the Amastridae is strongly supported in our molecular analyses, and there is also some support for the grouping of the Orculidae with the Pyramidulidae, and the Draparnaudiidae with the Gastrocoptidae. The findings of our molecular analyses support dividing the Orthurethra into three superfamilies: the Azecoidea, Chondrinoidea and Pupilloidea.
... Marianas, Samoa, Hawaii), usually after the declines had occurred. More reliable quantitative data on rates of decline have been gathered in the Ogasawara and Society islands (Clarke et al. 1984;Gerlach 1994Gerlach , 2001Coote et al. 1999;Coote and Loève 2003;Chiba and Cowie 2016). With these few exceptions there has been only limited scientific enquiry supported by robust experimental designs, appropriate sampling methodologies, and statistical analyses. ...
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Since 1955 snails of the Euglandina rosea species complex and Platydemus manokwari flat-worms were widely introduced in attempted biological control of giant African snails (Lissachatina fulica) but have been implicated in the mass extinction of Pacific island snails. We review the histories of the 60 introductions and their impacts on L.fulica and native snails. Since 1993 there have been unofficial releases of Euglandina within island groups. Only three official P. manokwari releases took place, but new populations are being recorded at an increasing rate, probably because of accidental introduction. Claims that these predators controlled L. fulica cannot be substantiated; in some cases pest snail declines coincided with predator arrival but concomitant declines occurred elsewhere in the absence of the predator and the declines in some cases were only temporary. In the Hawaiian Islands, although there had been some earlier declines of native snails, the Euglandina impacts on native snails are clear with rapid decline of many endemic Hawaiian Achatinellinae following predator arrival. In the Society Islands, Partulidae tree snail populations remained stable until Euglandina introduction, when declines were extremely rapid with an exact correspondence between predator arrival and tree snail decline. Platydemus manokwari invasion coincides with native snail declines on some islands, notably the Ogasawara Islands of Japan, and its invasion of Florida has led to mass mortality of Liguus spp. tree snails. We conclude that Euglandina and P. manokwari are not effective biocontrol agents, but do have major negative effects on native snail faunas. These predatory snails and flatworms are generalist predators and as such are not suitable for biological control.
... Marianas, Samoa, Hawaii), usually after the declines had occurred. More reliable quantitative data on rates of decline have been gathered in the Ogasawara and Society islands (Clarke et al. 1984;Gerlach 1994Gerlach , 2001Coote et al. 1999;Coote and Loève 2003;Chiba and Cowie 2016). With these few exceptions there has been only limited scientific enquiry supported by robust experimental designs, appropriate sampling methodologies, and statistical analyses. ...
Article
Full-text available
Since 1955 snails of the Euglandina rosea species complex and Platydemus manokwari flat-worms were widely introduced in attempted biological control of giant African snails (Lissachatina fulica) but have been implicated in the mass extinction of Pacific island snails. We review the histories of the 60 introductions and their impacts on L.
... Marianas, Samoa, Hawaii), usually after the declines had occurred. More reliable quantitative data on rates of decline have been gathered in the Ogasawara and Society islands (Clarke et al. 1984;Gerlach 1994Gerlach , 2001Coote et al. 1999;Coote and Loève 2003;Chiba and Cowie 2016). With these few exceptions there has been only limited scientific enquiry supported by robust experimental designs, appropriate sampling methodologies, and statistical analyses. ...
Article
Full-text available
Since 1955 snails of the Euglandina rosea species complex and Platydemus manokwari flatworms were widely introduced in attempted biological control of giant African snails (Lissachatina fulica) but have been implicated in the mass extinction of Pacific island snails. We review the histories of the 60 introductions and their impacts on L. fulica and native snails. Since 1993 there have been unofficial releases of Euglandina within island groups. Only three official P. manokwari releases took place, but new populations are being recorded at an increasing rate, probably because of accidental introduction. Claims that these predators controlled L. fulica cannot be substantiated; in some cases pest snail declines coincided with predator arrival but concomitant declines occurred elsewhere in the absence of the predator and the declines in some cases were only temporary. In the Hawaiian Islands, although there had been some earlier declines of native snails, the Euglandina impacts on native snails are clear with rapid decline of many endemic Hawaiian Achatinellinae following predator arrival. In the Society Islands, Partulidae tree snail populations remained stable until Euglandina introduction, when declines were extremely rapid with an exact correspondence between predator arrival and tree snail decline. Platydemus manokwari invasion coincides with native snail declines on some islands, notably the Ogasawara Islands of Japan, and its invasion of Florida has led to mass mortality of Liguus spp. tree snails. We conclude that Euglandina and P. manokwari are not effective biocontrol agents, but do have major negative effects on native snail faunas. These predatory snails and flatworms are generalist predators and as such are not suitable for biological control.
... It was noticed that land snail Succinea putris was more affected by soil moisture than M. cantiana which showed more resistance for dryness that also affected by the shelter of plants such as in case of clover makes soil moist and warm for long time followed by potato, lettuce and finally wheat. This shelter for these snails agreed with that reported by Godan (1983), El-Okda (1980), Satoshi (2003), Duncan (1983) and Coote (2003). ...
... The four orthurethran families Achatinellidae, Amastridae, Draparnaudiidae and Partulidae are endemic to the islands of the Pacific. Many of these Pacific species have narrow distributional ranges and are under severe threat from habitat destruction and introduced predators; amastrids, which are endemic to Hawaii, have almost all become extinct, and the loss of numerous achatinellid and partulid taxa has been well documented (see: Cowie, 1992;Coote & Loeve, 2003;Holland & Hadfield, 2004;Régnier et al., 2015). ...
Thesis
The phylogenetic relationships at the base of the stylommatophoran land snails and slugs have proven to be controversial, particularly the position of the Scolodontidae in relation to other stylommatophoran taxa. Likewise, the phylogenetic relationships within the hygrophilan freshwater snails and limpets are uncertain. This study provides molecular phylogenies for the Stylommatophora and Hygrophila at multiple scales including deep phylogenetic relationships of the major stylommatophoran and hygrophilan clades and family level relationships within the Orthurethra and Lymnaeoidea. In chapter 3, four standard markers: almost the full-length large subunit (LSU) rRNA gene (also incorporating part of the 5.8S gene), almost the full-length small subunit (SSU) rRNA gene, part of the histone three (H3) gene and the 1st and 2nd codon positions of the CO1 gene were used with the aim of resolving the basal divisions within the Stylommatophora and evaluating the phylogenetic utility of these markers. The deep phylogenetic relationships at the base of the Stylommatophora are now clearly resolved. The Scolodontidae are shown categorically to be the sister group to all other stylommatophoran taxa with robust support and with all phylogeny reconstruction methods. Based on this result, a taxonomic revision for the basal groups within the Stylommatophora has been proposed by reclassifying the ‘achatinoid’ and ‘non-achatinoid’ clades at a lower rank than the Scolodontina in order to properly reflect the deep-level relationships within the Stylommatophora. The original LSU 1-5 fragment used extensively in studies of the Stylommatophora is found to be the most informative gene fragment among the genes used in this study. Expanding the length of the LSU gene and combining it with other genes is necessary to fully resolve the relationships within the Stylommatophora, particularly those at the base of the clade. The family-group interrelationships within the Orthurethra were examined in chapter 4 using the ribosomal (r) RNA gene cluster [including part of the 5.8S gene, the complete ITS-2 region, and almost the full-length large subunit (LSU; 28S) gene]. There is robust support for the basal division between the Chondrinidae and the rest of the Orthurethra in our tree. Likewise, the monophyly of the Chondrinidae, Cerastidae, Vertiginidae, Achatinellidae and Partulidae is well supported while the Pupillidae, Enidae, and Valloniidae are not recovered as monophyletic groups in our orthurethran tree. Although there is relatively little support for the deep-level relationships among the main orthurethran groups, some groupings are strongly supported. The validity of the families and subfamilies within the Hygrophila was investigated in chapter 5 using the ribosomal (r) RNA gene cluster [including part of the 5.8S gene, the complete ITS-2 region, and almost the full-length large subunit (LSU; 28S) gene]. This study provides the most comprehensive sampling of the Hygrophila clade to date. The principle division of the Hygrophila into two monophyletic groups (the Chilinoidea and Lymnaeoidea) is robustly supported in our tree. The Acroloxidae, Lymnaeidae and Physidae are fully supported as monophyletic families. However, the Planorbidae are not supported as a monophyletic group due to the clustering of Bulinidae within the family. The subfamilies Amphipepleinae within the Lymnaeidae and both the Planorbinae and Ancylinae within the Planorbidae are strongly supported as monophyletic groups while the Aplexinae and Physinae within the Physidae and the Lymnaeinae within the Lymnaeidae are not recovered as monophyletic subfamilies. Based on the results of this study, a taxonomic revision for the hygrophilan families has been suggested by either retaining the Bulinidae as a family but reclassify the Ancylinae as a family outside the Planorbidae consistent with previous classifications or lowering the Bulinidae to subfamilial rank alongside the Ancylinae within the family Planorbidae. The interrelationships among the lymnaeoidean families (Acroloxidae, Bulinidae, Burnupiidae, Lymnaeidae, Physidae and Planorbidae) are reasonably well resolved in chapter 5 using a single standard marker, though they are not fully supported. Therefore, to better resolve these relationships we have undertaken a more detailed phylogenetic analyses in chapter 6 using four standard molecular markers [LSU (incorporating 5.8S), SSU, H3 and 1st and 2nd codon positions of the CO1gene] for a representative taxa from the main hygrophilan groups within a framework of the Panpulmonata combined with a phylogenomic analysis based on transcriptome sequences data for a representative from each of the main lymnaeoidean families (Acroloxidae, Lymnaeidae, Physidae and Planorbidae). The observed interrelationships among the lymnaeoidean families based on the four standard markers are consistent with those obtained in chapter 5, but surprisingly support for the major division decreases raising uncertainty about the topology. However, the problematic interrelationships between the lymnaeoidean families are well resolved in our phylogenomic analysis, with the Acroloxidae recovered as the sister group to a clade comprising the Lymnaeidae, Physidae and Planorbidae, the Physidae recovered as the sister group of a cluster comprising the Lymnaeidae and Planorbidae, and the Lymnaeidae and Planorbidae recovered as sister taxa.
... Ainsi, l'introduction de gastéropodes comme l'achatine (Achatina fulcata) dans les îles polynésiennes semble être à l'origine de la disparition de nombreuses espèces autochtones et spécifiques de chacune de ces îles, comme les gastéropodes du genre Partula. Il semble d'ailleurs que le processus d'extinction de ces Partula soit en partie indirect et, comme hélas beaucoup d'introductions d'espèces, résulte d'une action qui se voulait positive : c'est en effet pour lutter contre l'achatine, qui devenait un fléau pour l'agriculture, qu'a été introduit un gastéropode carnivore, Euglandina rosea, qui n'a pas éliminé l'achatine mais a décimé les populations de Partula (Clarke et al., 1984 ;Coote et Loève, 2003). Parmi les autres introductions problématiques, on peut citer les introductions en Europe occidentale de la moule zébrée (Dreissena polymorpha), espèce originaire de la mer Caspienne, de la crépidule (Crepidula fornicata) venant d'Amérique du Nord, qui ont conduit à des phénomènes de compétition trophique au détriment des espèces indigènes de mollusques bivalves (Lévêque, 2007) ainsi que celle de l'écrevisse américaine Pacifastacus leniusculus, qui a contribué à la raréfaction des espèces indigènes d'écrevisse, en étant porteuse saine d'un champignon pathogène pour ces espèces (Laurent, 1997). ...
Article
L'introduction et le succès du terme « biodiversité » ont concrétisé plusieurs évolutions récentes dans notre perception et notre compréhension de la diversité des êtres vivants. Nous avons évoqué dans deux articles précédents l'ampleur insoupçonnée de la diversité spécifique, l'existence d'autres niveaux d'organisation que celui de la diversité des espèces et la nécessité de reconsidérer notre vision de l'utilité et de la stabilité de la biodiversité. Nous examinons dans cet article la question de l'érosion forte de cette biodiversité sous l'action des différentes activités humaines. Nous présentons les différentes approches permettant de mesurer cette érosion et de la comparer aux taux d'extinction passés, estimés par les paléontologues. Les causes de cette érosion sont ensuite évoquées : surexploitation, destruction des habitats, introduction d'espèces. En prenant l'exemple de la pêche industrielle, nous insistons sur le fait que les impacts indirects et non intentionnels jouent sans doute un rôle plus important que les impacts directs, d'où l'échec des modes de gestion focalisés exclusivement sur les espèces exploitées. Enfin, nous analysons les conséquences possibles des changements globaux annoncés pour le XXIe siècle. Nous montrons que notre connaissance des différents modes d'adaptation de la biodiversité est aujourd'hui très limitée, en particulier si la question à résoudre n'est pas : « La biodiversité peut-elle s'adapter ? » mais « Les adaptations qui vont se réaliser seront-elles ou non favorables à la vie humaine ? ». Nous concluons sur la nécessité de remplacer une vision linéaire des relations entre connaissance et action par la notion de « spirale d'apprentissage », dans laquelle les questions « Que voulons-nous ? » et « Que savons-nous ? » mobilisent de manière interactive l'ensemble des acteurs.
... Predatory snails of the genus Euglandina have been introduced to numerous islands in the Pacific in an effort to control the giant African snail, Lissachatina fulica (Bowdich, 1822). The environmental cost of this programme has been the extinction of numerous partulids and other native land snails (Clarke et al., 1984;Civeyrel & Simberloff, 1996;Coote & Loève, 2003;USFWS, 2016). Similarly, the predatory flatworm Platydemus manokwari de Beauchamp, 1963 has been used in the control of L. fulica (Winsor et al., 2004) even though it poses a similar threat to native land snails (Ohbayashi et al., 2007;Sugiura & Yamaura, 2009;USFWS, 2016). ...
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A summary of field work and finds in Jamaica from July 2018. Researchers include Gary Rosenberg, Makiri Sei, and Richard Goldberg.
... Predatory snails of the genus Euglandina have been introduced to numerous islands in the Pacific in an effort to control the giant African snail, Lissachatina fulica (Bowdich, 1822). The environmental cost of this programme has been the extinction of numerous partulids and other native land snails (Clarke et al., 1984;Civeyrel & Simberloff, 1996;Coote & Loève, 2003;USFWS, 2016). Similarly, the predatory flatworm Platydemus manokwari de Beauchamp, 1963 has been used in the control of L. fulica (Winsor et al., 2004) even though it poses a similar threat to native land snails (Ohbayashi et al., 2007;Sugiura & Yamaura, 2009;USFWS, 2016). ...
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Twenty-four (24) endemic non-marine gastropod species (three (3) freshwater, Twenty-one (21) terrestrial) have been recorded in Santa Catarina State/ SC on the Atlantic Slope of Southern Brasil, representing 17 genera and 10 families ... < see pp. 33-34 >
... Predatory snails of the genus Euglandina have been introduced to numerous islands in the Pacific in an effort to control the giant African snail, Lissachatina fulica (Bowdich, 1822). The environmental cost of this programme has been the extinction of numerous partulids and other native land snails (Clarke et al., 1984;Civeyrel & Simberloff, 1996;Coote & Loève, 2003;USFWS, 2016). Similarly, the predatory flatworm Platydemus manokwari de Beauchamp, 1963 has been used in the control of L. fulica (Winsor et al., 2004) even though it poses a similar threat to native land snails (Ohbayashi et al., 2007;Sugiura & Yamaura, 2009;USFWS, 2016). ...
Article
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Ten (10) new species (eight (8) gastropods, six (6) native, two (2) non-native invasives) and two (2) native bivalves were added to the current inventory of non-marine molluscs occurring in the state of Santa Catarina/ SC, the small geographically central portion of southern Brasil, part of the Atlantic slope of South America. This addition means that there are now 242 species and subspecies confirmed in the State, including 28 non-native species: 24 gastropods, four bivalves ... (see pp. 29-30)
... Predatory snails of the genus Euglandina have been introduced to numerous islands in the Pacific in an effort to control the giant African snail, Lissachatina fulica (Bowdich, 1822). The environmental cost of this programme has been the extinction of numerous partulids and other native land snails (Clarke et al., 1984;Civeyrel & Simberloff, 1996;Coote & Loève, 2003;USFWS, 2016). Similarly, the predatory flatworm Platydemus manokwari de Beauchamp, 1963 has been used in the control of L. fulica (Winsor et al., 2004) even though it poses a similar threat to native land snails (Ohbayashi et al., 2007;Sugiura & Yamaura, 2009;USFWS, 2016). ...
Article
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In the new version of the Invertebrates Red Book of Brasilian Fauna Threatened with Extinction (ICMBio, 2018 - Volume 7) 23 species of molluscs are included and allocated to IUCN Red List categories: eight (8) Critically Endangered, nine (9) Endangered and six (6) Vulnerable. Among these, six (6) are marine (one (1) bivalve, five (5) gastropods), eight (8) are terrestrial and nine (9) are freshwater (two (2) bivalves, seven (7) gastropods) ...< see pp. 32-33 >
... Predatory snails of the genus Euglandina have been introduced to numerous islands in the Pacific in an effort to control the giant African snail, Lissachatina fulica (Bowdich, 1822). The environmental cost of this programme has been the extinction of numerous partulids and other native land snails (Clarke et al., 1984;Civeyrel & Simberloff, 1996;Coote & Loève, 2003;USFWS, 2016). Similarly, the predatory flatworm Platydemus manokwari de Beauchamp, 1963 has been used in the control of L. fulica (Winsor et al., 2004) even though it poses a similar threat to native land snails (Ohbayashi et al., 2007;Sugiura & Yamaura, 2009;USFWS, 2016). ...
... Euglandina spp.), have been implicated in the decline, extirpation and extinction of native terrestrial gastropod species throughout the Pacific (e.g. Hadfield 1986;Gerlach 2001;Coote and Loève 2003;Meyer and Cowie 2010a;Gargominy et al. 2011;Curry et al. 2016). Non-native terrestrial gastropods (e.g., Limax maximus, Limacus flavus, Deroceras laeve, Veronicella cubensis) have also been highlighted as an important factor contributing to plant endangerment (Joe and Daehler 2008;Shiels et al. 2014). ...
Article
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To preserve native floras and faunas of tropical oceanic islands, it is critical to limit the establishment of terrestrial non-native gastropods (i.e. snails, including slugs), particularly those from temperate regions, as they can become abundant in high elevation areas, often the last refuges of native species. In Hawaii, the horticultural trade has been associated with many introductions, but threats posed by nurseries at high elevations have not been assessed. To examine these potential threats, we surveyed gastropods in 21 high elevation (> 500 m) horticultural/agricultural facilities on three Hawaiian Islands (Oahu, Maui and Hawaii) and compared these surveys to 31 previous low elevation nursery surveys (< 500 m) on the same islands. High elevation nurseries harbored distinct non-native gastropod assemblages, which were composed primarily of species from temperate regions. Gastropods from temperate regions had larger elevation ranges in nurseries than those from tropical areas. Our results highlight that nurseries, particularly those at higher elevations, represent key sources for establishment of temperate gastropods, a critical threat to the remaining Hawaiian biodiversity. We also found that high elevation nurseries on Maui and Hawaii supported non-native species not found in Oahu nurseries, indicating that Oahu may not be the only source of introductions into high elevation nurseries. We hope these results will spur active control of non-native gastropods in nurseries, particularly those at higher elevations, to potentially prevent further ecological damage to the already imperiled Hawaiian flora and fauna.
... Land snails have seriously declined on oceanic islands, because of habitat loss and the impacts of introduced non-native species (Coote & Loéve, 2003;Lydeard et al., 2004;Chiba & Cowie, 2016;Cowie et al., 2017). One example is the helicarionid land-snail genus Hirasea. ...
Article
Confirming the extinction of species with only old occurrence records is often difficult, due to the scarcity of biological information. Phylogenetic position and taxonomic status of the potentially extinct species are unclear in most such cases. In the present study, we document that a species of the endemic genus Hirasea of the oceanic Ogasawara Islands, which was formerly believed to have become extinct, still survives, on the basis of combined surveys involving molecular phylogenetics and morphometrics. Hirasea is notorious for its highly diversified shell morphologies and a number of species and subspecies have already become extinct because of environmental changes and impacts of alien predators. In this study, we first reconstruct phylogenetic relationships among extant Hirasea populations. Next, on the basis of quantitative shell morphological analysis of extant populations and type specimens, we identify morphological traits that reflect phylogenetic relationships among the species. By using these morphological traits and molecular phylogenies, we demonstrate that H. nesiotica liobasis, previously considered extinct, is still extant on Chichijima. Although classifications by means of morphology and molecular phylogeny often show incongruences, judgement of the conspecific status of living and extinct populations is still possible by considering ranges of variation and phylogenetic constraints on morphological traits.
... Notably, active expansion of this species beyond the northern border of the range in Eastern Europe was observed in recent decades (Snegin and Prisnyi, 2008;Balashov et al., 2013). This type of invasive process development can possibly have a pronounced effect on the local malacofauna and the local ecosystems as a whole (Clarke et al., 1984;Murray et al., 1988;Parker et al., 1999;Coote and Loeve, 2003). ...
Article
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Gel electrophoretic analysis of allozymes was used to study the genetic structure of the population of the alien mollusk Stenomphalia ravergiensis that inhabits urbanized landscapes in the town of Belgorod (Russia). A high genetic variability level and low values of inbreeding coefficient were characteristic of most colonies. Weak genetic separation of the snail groups studied was also demonstrated. Invasive colony distribution was supposed to correspond to the island model. The calculation of effective population size and the comparison of this value to the respective parameters of native and invasive species of terrestrial mollusks revealed a high viability level for the population of the species of interest in the study area.
... Predation by introduced animals has been a major cause of the decline of land snails. In the Southeast Pacific region, the exotic carnivorous land snail Euglandina rosea exterminated 56 of the 61 endemic arboreal land snails after its introduction in a biological control program targeting the giant African snail, Achatina fulica (Coote & Loeve, 2003). In the Bonin Islands, Japan, the introduced rat Rattus rattus severely preys upon native land snail species, which have extensively radiated throughout a unique evolutionary history (Chiba, 2009). ...
... Стоит отметить, что в последние десятилетия наблюдается активное расселение это-го вида за пределы северной границы своего ареала на территории Восточной Европы [Снегин, Присный, 2008;Balashov et al., 2013]. Известно, что такое развитие инвазионного процесса, может оказать существенное влияние на местную малакофауну и экосистемы в целом [Clarke et al., 1984;Murray et al., 1988;Parker et al., 1999;Coote, Loeve, 2003]. ...
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15.11.16 На основе данных, полученных методом гель-электрофореза аллозимов, изучена генетическая структура популяции чужеродного моллюска Stenomphalia ravergiensis, обитающего в условиях ур-банизированного ландшафта на территории города Белгород. В большинстве колоний выявлен высо-кий уровень генетической изменчивости и низкие показатели коэффициента инбридинга. Также ус-тановлена слабая генетическая подразделённость изучаемых групп улиток. Выдвигается предполо-жение, что распределение адвентивных колоний соответствует островной модели. Расчёт эффектив-ной численности и сопоставление её с аналогичными показателями фоновых и адвентивных видов наземных моллюсков продемонстрировали высокий уровень жизнеспособности популяций изучае-мого вида в районе исследования. Ключевые слова: чужеродный вид, наземный моллюск, генетическая структура, аллозимы. Введение Известно, что непреднамеренная интродук-ция животных и растений в различные точки планеты может привести к непредсказуемым последствиям, как для самих видов интроду-центов, так и для членов аборигенных сооб-ществ. При этом адвентивные колонии, ока-завшись в новых условиях обитания, могут служить хорошими естественными моделями для проверки наших представлений о механиз-мах эволюции. Согласно традиционным взгля-дам, в таких колониях, в силу эффекта осно-вателя [Mayr, 1954], должно происходить со-кращение аллельного разнообразия, которое усугубляется дальнейшим инбридингом, вследствие чего наступает потеря устойчиво-сти и вымирание. Вероятно, это является од-ной из причин того, что далеко не все случаи интродукции заканчиваются успешно. Поэто-му распространение вида за пределы искон-ного ареала предполагает достаточно высокий уровень генетической и фенотипической из-менчивости, что обеспечивает адаптации к новым условиям и освоение новых местооби
... Стоит отметить, что в последние десятилетия наблюдается активное расселение это-го вида за пределы северной границы своего ареала на территории Восточной Европы [Снегин, Присный, 2008;Balashov et al., 2013]. Известно, что такое развитие инвазионного процесса, может оказать существенное влияние на местную малакофауну и экосистемы в целом [Clarke et al., 1984;Murray et al., 1988;Parker et al., 1999;Coote, Loeve, 2003]. ...
Article
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The genetic structure of populations of alien mollusk Stenomphalia ravergiensis, living in the urbanized landscape in Belgorod, is studied on the basis of data obtained by allozyme gel electrophoresis. A high level of genetic variability and low levels of inbreeding coefficient and poor genetic subdivision of the studied group of snails are revealed in the most of the colonies. It is suggested that the distribution of the invasive colonies corresponds to the island model. Calculation of the effective population size and it's comparing with the ones of native and invasive snail species showed a high level of viability of the studied populations in the study area
Article
The study of both animal colouration and patterning across the natural world has been imperative for understanding some of the key principles of biology throughout the past century, particularly with respect to evolution and genetics. Generally, colour and pattern have each been described qualitatively, often being binned into discrete groups relying on human perception of colour or pattern, rather than being considered in a biologically relevant context. ‘Binning’ traits into discrete groups has the consequence that variation within discrete morphs is often overlooked. Terrestrial gastropods, such as the selected study genera Cepaea and Auriculella, provide an ideal system for the study of polymorphisms and colour variation due to the extreme variety of morphs present across the taxa, as well as the nature of shell growth providing a complete ontogeny of an individual. The aims of this thesis are threefold; firstly, I aimed to understand finescale variation within and between established banding pattern morphs in Cepaea, to allow inferences to be made regarding the genetic mechanisms responsible for this variation. The implementation of two quantitative methods for measuring variation in band position and width in individual shells found that individual band absence has a minor but significant effect on the position of the remaining bands, implying that the locus controlling band presence/absence acts mainly after the position of bands is determined. I establish a method which is useful for comparative studies of quantitative banding variation in snail shells, and for extraction of growth parameters and morphometrics, highlighting the importance and usefulness of gastropod shells in the understanding of how variation is established and maintained in a population. Secondly, I aimed to understand the shell colour variation present in both Cepaea nemoralis and Cepaea hortensis by using spectrophotometry and psychophysical modelling in tandem. It was revealed that colour variation in Cepaea hortensis is continuous, with no detectable effects of geographic location with the exception of an association of the paleness of yellow shells with latitude. Differences between the colour of Cepaea hortensis and Cepaea nemoralis, both in terms of exact shade and overall colour were revealed; Cepaea hortensis are generally paler, and less pink-toned, but slightly more brown-toned. Precise shade variation of yellow individuals from genetically diverse lineages of Cepaea nemoralis were also detected. The results presented have significance in furthering the understanding of the precise nature of the colour polymorphism displayed in Cepaea spp., and the nature of the selection which acts upon it, as well as highlighting the importance of considering colour as a continuous trait, rather than binning it into discrete groups. Thirdly, I aimed to investigate colour variation across a number of scales in the Hawaiian land snail genus Auriculella, to allow inferences about the genetic architecture responsible for the variation, and to highlight the usefulness of museum collections of gastropod shells in understanding variation in extinct or endangered species. I demonstrated that there are differences in colour within single shells of Auriculella, similar to variation displayed by other Pacific Island snails. I described significant variation between isolated populations of the same species, and determined that there is no difference in colour variation between shells on the islands of Maui and Oahu. Finally, I demonstrated that there is no difference in colour between shell chiralities, suggesting that interchiral mating is not uncommon, and that the loci responsible for colour variation and chirality are not closely linked. By describing the variation present in Auriculella in a biologically relevant context, inference regarding genetic mechanisms of variation becomes possible in a taxa of conservation concern. By achieving these aims, and synthesising conclusions drawn from their achievement, I have highlighted the importance of accurately defining phenotypes for the purposes of evolutionary ecology and genetics. Defining phenotypes and investigating variation present within morphs has allowed inferences to be made regarding the underpinning genetic mechanisms which control variation in two gastropod genera, although the principles are applicable to other taxonomic groups. Finally, and more broadly, I have demonstrated the usefulness of gastropods as study systems, particularly where large collections of shells are available.
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Recently, an Environmental Impact Assessment (EIA) was submitted for consideration to the National Environmental and Planning Agency (NEPA) of Jamaica by Noranda Jamaica Bauxite Partners II (NJBP II) in regards to a permit application to mine an area called SML-173 (Conrad Douglas & Associates Limited, 2020) (Fig. 1). SML-173 (SML standing for Special Mining Lease) is a part of Cockpit Country, which is the largest contiguous mesic limestone forest on the island and home to many endemic molluscan and other invertebrate species that cannot be found elsewhere on Jamaica. Cockpit Country has large reserves of aluminium-bearing soils (bauxite) and is constantly under threat of disturbance and mining despite protection measures. We provided critique and commentary to NEPA on the EIA, rejecting it for its inadequacies, including unclear reporting, lack of research and citations, unclear field methodologies and inaccurate results. We share a summary of some of these comments here to report on ongoing conservation issues and concerns for Jamaican terrestrial molluscs.
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The endemic, Critically Endangered greater Bermuda land snail Poecilozonites bermudensis is known from only two relict subpopulations. Little is known of its habitat preferences in the wild. Observations of released zoo-reared P. bermudensis suggested an affinity for limestone, which we investigated on Port's Island. Previous qualitative observations on Port's Island suggested an aversion to the litter of the invasive tree Casuarina equisetifolia , which we examined. Additionally, we hypothesized that snail abundance would increase with elevation, distance from the sea, and with increased plant species diversity. During 2 May–14 June 2018, we found 558 live P. bermudensis at 70 sites across Port's Island. We found no correlation between the number of live snails at a site and either the number of plant species, elevation or distance from the shoreline, but snails were significantly less abundant at sites dominated by C. equisetifolia . Significantly more snails were found around limestone features, indicating future reintroductions and searches for any undiscovered subpopulations should focus on limestone features where C. equisetifolia is absent.
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The small, the hidden, the less-loved: conserving other species - Volume 53 Issue 2 - Martin Fisher
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Many people from all walks of life have observed, utilized and investigated snails for thousands of years. These human activities have embraced snails in the ocean, in freshwater and on land because snails are one of the few animal groups that have successfully diversified and adapted to exploit all three of these main environments. Countless numbers of people have interacted with snails from a young age because they were either good to eat, practically useful or biologically fascinating. The latter two points are well illustrated by the production of pain killers many times stronger than morphine from snail toxins and by the stunning manufacture of a mega-diverse variety of snail shell forms. The fact is, snails can be found almost everywhere you go on our planet, from the bottom of the sea to the tops of mountains, and significantly they are also found in the every-day existence of people from all walks of life. However, despite their ubiquitous occurrence, there is a critical gap in the use of snails and other similarly diverse invertebrate species, in estimating the extent of our planets biodiversity, and in discussions and debates on the economic value of biodiversity. The magnitude of invertebrate contributions to ecosystem services, ecosystem function and human livelihoods is considerably under acknowledged. Therefore, to date, snails are largely unrecognized as a hugely diverse and highly valuable natural resource, many of which may be lost before their contribution to the quality of life on our planet is adequately recognized by managers and decision makers at all levels of society. Thus, we here collate and highlight a snap shot of information on the value of snails in relation to food and medicine, their use by traditional indigenous cultures in addition to their considerable significance with regards to biodiversity, and the current extinction rate of snails on tropical islands.
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The ocurrence of the exotic giant african snail "Achatina (Lissachatina) fulica (Bowdich, 1822)" in the "Pampas Biome" environment domain is available/ confirmed for first time for South America, in the Metropolitan area of the "Greater Porto Alegre", Southernmost Brazil region (see pp. 21-22) ......................
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The first geographical occurrence record of native forest snails "Orthalicus Beck, 1837" in the State of Santa Catarina/ SC and the Southern Brazil region in general is available (see pp. 33-34) ........
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LIFE HISTORY AND REPRODUCTIVE AND THERMAL BIOLOGY OF ASOLENE PLATAE, AN APPLE SNAIL FROM THE RÍO DE LA PLATA BASIN (ARGENTINA)
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Land snails of the genus Partula Fer. inhabiting the island of Moorea in French Polynesia show complex patterns of partial speciation. The late H. E. Crampton described eleven species from the island. Two have since been relegated to the genus Samoana. Of the remaining nine taxa, as many as four may coexist at a single locality without evidence of hybridization. Nevertheless an allele appearing in any of the taxa is potentially capable of spreading to any of the others, although in the process it may have to pass through several intervening taxa. Large morphological, ecological and behavioural differences have evolved despite this potential for gene flow. The biological differences are not reflected in 20 enzyme loci surveyed by conventional starch-gel electrophoresis, nor in the numbers of chromosomes. It is clear that a significant part of the morphological divergence between taxa has taken place of Moorea. Our observations are consistent with the view that all the Moorean taxa (excepting Samoana) are descendants of a single ancestral invasion, although the possibility of more than one invasion cannot be excluded. The pattern of differentiation shows at least two cases of circular overlap (`ring species'), with diameters of 2 and 3 km, and several apparent examples of character displacement. Coexisting taxa tend to partition the available habitat, although the separation is never complete.
Article
We have studied the habitats occupied by snails of the genus Partula on the island of Moorea in French Polynesia. Discriminant analysis of samples containing two, three or four sympatric species shows that the taxa divide the available habitat so that each predominates in its own characteristic environment. The most important factor determining the numbers of species within habitats is the density and size of the climbing pandanus plant Freycinetia. Although all the species can use this plant, `specialists' restrict its occupation by `generalists'. The number of species at any locality depends on the habitat, but the particular array of species seems to be influenced both by interspecific interactions and by the history of colonization.
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The current distribution of endemic partulid snails on Tahiti in French Polynesia reflects the danger of ignoring expert advice and introducing an alien species into a fragile island ecosystem. The endemic tree-snail fauna of the island now faces extinction. Although the extinction of the native species of Partula (Partulidae; Polynesian tree snails) on Moorea in French Polynesia is well known in the world of conservation biology, losses on other Pacific islands are less well described. This paper presents an update on the status of partulid snail populations on Tahiti in the light of fieldwork undertaken between 1995 and 1997. Native snails still exist in good numbers in two areas, at opposite ends of the island. In other areas, sightings of single or a few individuals indicate remnant populations now on the edge of extinction. Efforts to protect these populations and others in French Polynesia are being planned in collaboration with local government authorities.