(DRAFT) - Taxonomy
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
TAXONOMY
NAME - SNAIL, TREE, OAHU
OTHER COMMON NAMES - SNAIL, TREE, OAHU;SHELLS, AGATE and LITTLE;PUPU KUAHIWI;PUPU KANIOE
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - MOLLUSCA,
CLASS AND SUBCLASS - GASTROPODA,
ORDER AND SUBORDER - STYLOMMATOPHORA,
FAMILY AND SUBFAMILY - ACHATINELLIDAE,
GENUS AND SUBGENUS - ACHATINELLA,
SPECIES AND SSP - SPP.,
SCIENTIFIC NAME - ACHATINELLA SPP.
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Oahu Tree Snail
Achatinella spp. Swainson, 1828
KINGDOM: Animal GROUP: Snail
PHYLUM: Mollusca CLASS: Gastropoda
ORDER: Stylommatophora FAMILY: Achatinellidae
Oahu (O'ahu) tree snails are medium-sized land snails with shells
12-30 mm in height (adults), usually ovate in shape, often brightly
colored. A more complete description of shell morphology is as
follows: "Shell imperforate or minutely perforate, oblong, ovate or
globose-conic, smooth or longitudinally corrugated, with only minute
and weak traces of spiral sculpture; color in spiral bands or streaks
in the direction of growth-lines, never in forwardly-descending
stripes; lip simple or thickened within, sometimes slightly expanding;
columella bearing a strong callous fold" (41).
Achatinella is closely related to Partulina, a genus of tree
snails occurring on the islands of Oahu, Molokai, Lanai, Maui, and
Hawaii. Achatinella is distinguished from Partulina by differences in
color pattern (forwardly-descending stripes are usually present in
Partulina, never in Achatinella) and shell sculpture (spiral groves
usually present in Partulina, absent in Achatinella) (41).
Taxonomy - 1 (DRAFT) - Taxonomy
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
Achatinella has been subjected to numerous taxonomic changes at
both the generic and specific level. In the 18th and early 19th
centuries, species now placed in Achatinella were described in such
unrelated genera as: Helix Linnaeus, 1758; Turbo Linnaeus, 1758;
Achatina Lamarck, 1799; and Monodonta Lamarck, 1799. Recognized
synonyms of Achatinella Swainson, 1828, include: Helicteres
Beck, 1837; Apex von Martens, 1860; Helicter Pease, 1862; and
Helicterella Gulick, 1873: currently recognized subgenera of
Achatinella include Achatinella, Bulimella Pfeiffer, 1854; and
Achatinellastrum Pfeiffer, 1854 (14,41). During the 19th century
many many species-level taxa now assigned to other genera of the
subfamily Achatinellinae (Partulina Pfeiffer, 1854, Newcombia
Pfeiffer, 1854, and Perdicella Pease, 1869) were described as
species of Achatinella, as were a number of species now assigned to
the family Amastridae. As currently defined, Achatinella has the
limits set for it by Pilsbry and Cooke (41); the differences said to
distinguish Partulina from Achatinella are not of great magnitude,
however, their separation at the generic level could be disputed.
At the species level, the extreme diversity of color pattern
exhibited by Achatinella caused 19th century workers to described a
multitude of "species," many of which have been synonymized by later
workers. The excellent monograph of this genus by Pilsbry and Cooke
(41) recognized 41 species; in a review of the taxonomy of the genus,
they noted that more than 170 species-level names were available, most
originally proposed as species, and that among previous workers
Baldwin (04) had recognized 106 species, while Sykes (49) had reduced
this to 72. More recently, Welch (59,60,61) proposed a further
reduction in the number of recognized species by consolidating several
of Pilsbry and Cooke's "series" of species. Welch's A. apexfulva
included all members of Pilsbry and Cook's "series of A. apexfulva"
(A. apexfulva, A. leucorrhaphe, A. turgida, A. swiftii, A. cestus, and
A. vittata), plus A. valida; he also reduced Pilsbry and Cooke's
"series of A. bulimoides" (A. bulimodes, A. elegans, and A. rosea) to
a single species. Welch's treatment is more in accord with modern
species concepts than is that of Pilsbry and Cooke, but has not been
generally adopted by others (e.g. 27,33,34,53,54), probably because
of the recognized excellence of the Pilsbry and Cooke monograph and a
reluctance to deal with Welch's excessive numbers of newly recognized
subspecies (his 1938 review of A. mustelina (58), for example,
recognized 26 named subspecies, 21 of them new in that work). It is
probable that a modern revision of the genus would extend Welch's
practice of considering Pilsbry and Cooke's "species series" as being
approximately equivalent to individual species; likely candidates for
such treatment include the "series of A. byronii" (A. byronii and such
probable synonyms as A. pulcherrima, A. lila, and A. decipiens; the
"series of A. viridans" (A. viridans, A. abbreviata, and A. taeniolata
probably belongs here also), the "series of A. fuscobasis"
(A. fuscobasis, A pupukanioe, and A. sowerbyana), "series of
A. vulpina" (A. vulpina, A. stewartii, A. fulgens, A. phaezona, with
A. buddii possibly distinct), "series of A. casta" (A. casta,
A. bellula, and A. Juncea), and the "series of A. livida" (A. livida,
A. juddii, A. curta, A. dimorpha, and A. caesia). Such a reduction
would leave 12-16 valid species (09).
Taxonomy - 2 (DRAFT) - Taxonomy
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
The principal reference for species identification is the
monograph of the genus by Pilsbry and Cooke (41). Additional
information is provided in Welch's works (58,59,60,61). Anatomical
data are provided in Pilsbry and Cooke (41) and Cooke and Kondo (14).
Original descriptions of most species were reprinted by Thwing (51).
It is believed that the following species of Achatinella
(following the classification of Pilsbry and Cooke (41)) are extant
(53,54):
Achatinella apexfulva (Dixon, 1789)
Achatinella bellula Smith, 1873
Achatinella bulimoides Swainson, 1828
Achatinella byronii Wood, 1828
Achatinella concavospira Pfeiffer, 1859
Achatinella curta Newcomb, 1853
Achatinella decipiens Newcomb, 1854
Achatinella fulgens Newcomb, 1853
Achatinella fuscobasis Smith, 1873
Achatinella leucorrhaphe (Gulick, 1873)
Achatinella lila Pilsbry, 1914
Achatinella lorata (Ferussac, 1824)
Achatinella mustelina Mighels, 1845
Achatinella pulcherrima Swainson, 1828
Achatinella pupukanioe Pilsbry and Cooke, 1914
Achatinella sowerbyana Pfeiffer, 1855
Achatinella swiftii Newcomb, 1853
Achatinella taeniolata Pfeiffer, 1846
Achatinella turgida Newcomb, 1853
The following species of Achatinella are presumed to be extinct
(53,54). It should be noted that living populations of several of
these "extinct" species were observed as recently as the 1960's.
Therefore, it is possible that a thorough search would reveal that
one ore more of these taxa still survive (06,09). Due to limited
space in the scientific name synonyms field (field "SCI-NAMES") the
following species keywords are not contained in that field:
Achatinella abbreviata Reeve, 1850
Achatinella buddii Newcomb, 1853
Achatinella caesia Gulick, 1858
Achatinella casta Newcomb, 1853
Achatinella cestus Newcomb, 1853
Achatinella decora (Ferussac, 1821)
Achatinella dimorpha Gulick, 1858
Achatinella elegans Newcomb, 1853
Achatinella juddii Baldwin, 1895
Achatinella juncea Gulick, 1856
Achatinella lehuiensis Smith, 1873
Achatinella livida Swainson, 1828
Achatinella papyracea Gulick, 1856
Achatinella phaezona Gulick, 1856
Achatinella rosea Swainson, 1828
Achatinella spaldingi Pilsbry and Cooke, 1914
Taxonomy - 3 (DRAFT) - Taxonomy
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
Achatinella stewartii (Green, 1827)
Achatinella thaanumi Pilsbry and Cooke, 1914
Achatinella valida Pfeiffer, 1855
Achatinella vittata Reeve, 1850
Achatinella viridans Mighels, 1845
Achatinella vulpina (Ferussac, 1824)
Common name synonyms for this species are; Little agate shells,
pupu kuahiwi (Hawaiian)(25), and another Hawaiian name pupu kanioe,
is the source name of A. pupukanioe Pilsbry and Cooke.
Taxonomy - 4 (DRAFT) - Status
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
STATUS
Coded Status
E: Federal Endangered
Commercial
Game (Consumptive Recreational)
Ceremonial/Cultural
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
O'ahu tree snails (Achatinella spp.) have been designated
Endangered species pursuant to the Endangered Species Act of 1973
(50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as
amended. The genus has this status wherever found including the
State of Hawai'i.
These species are protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild
animal (alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation or foreign law; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
DOD -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
Status - 1 (DRAFT) - Status
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
STATE STATUSES AND LAWS:
STATE: Hawai'i
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Div. of Forestry and Wildl., Dept. of
Land and Nat. Res.
STATE STATUTE: Hawai'i Rev. Stat. Chapt. 195D.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The genus is not listed by CITES. Listing by CITES should be
considered, as the shells of Achatinella are undoubtedly still traded.
It is listed as endangered by the IUCN Red Data Book.
ECONOMIC STATUSES:
The "singing" of tree snails is a favorable theme of ancient
Hawaiian verse, a tradition carried on today by a few popular songs
(in this case the Hawaiians were wrong - crickets actually do the
singing attributed to land snails).
The richly colored O'ahu tree snails also captured the
imaginations of expatriate Americans and their descendents, many
of whom collected thousands of shells durring the late 1800's and
early 1900's. A few resident naturalists studying the evolution of
Achatinella ultimately discovered one of the earliest recognized
examples of the allopatric speciation (64). Appreciation for tree
snails helped inspire a more general awareness of the diversity and
uniqueness of the Hawaiian flora and fauna. Unfortunately, collecting
reduced certain localized populations of tree snails; nevertheless,
most species survived even in popular collecting localities, until
the introduction of the carnivorous snail, Euglandina rosea. Few
people now collect tree snails; in fact, most of Oahu's 800,000
residents have never seen one, nor are even aware of the tree snails'
celebrated history and troubled future.
The Achatinella tree snails still attract considerable scientific
interest. Belonging to the subfamily Achatinellinae of tree snails
endemic to the Hawaiian Archipelago, and as members of the
proportionately enormous native land snail fauna of these islands
(roughly 1000 spp.), the O'ahu tree snails show numerous adaptations
in morphology, and ecology peculiar to the evolution of land molluscs
on islands. They also demonstrate well, and call attention to, the
problems faced by other Hawaiian terrestrial snails, many of which are
likewise endangered or already extinct.
79/09/17:44 FR 54011 - Review of status.
80/06/26:45 FR 43358/43360 - Proposed rule.
81/01/13:46 FR 03178/03182 - Final rule, Listed as Endangered.
81/02/04:46 FR 10707/10708 - Ext. of effective dates of rules.
81/02/12:46 FR 11999 - Correction.
81/03/30:46 FR 19233/19234 - Ext. of dates, with comments.
81/04/30:46 FR 24186/24187 - Def. of eff. dates of rules w/comments.
81/06/29:46 FR 33278/33279 - Def. of eff. dates of rules w/comments.
81/08/06:46 FR 40025/40026 - Deferal of dates for final rule.
83/07/27:48 FR 34182/34196 - Updated list.
Status - 2 (DRAFT) - Status
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
87/07/07:52 FR 25523/25528 - Notice of Review
87/09/23:52 FR 35743/35748 - Proposed addition to CITIES
87/12/28:52 FR 48820/48823 - Final rule;listed in CITES-I
Status - 3 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
LAND USE -
Shrub and Brush Rangeland
Evergreen Forest Land
Forested Wetland
Nonforested Wetland
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Palustrine SS3
Palustrine FO3
Palustrine SS3
Palustrine FO3
COMMENTS ON HABITAT ASSOCIATIONS -
Achatinella occurs primarily in subtropical moist or tropical
wet evergreen forest land (principally ohia lehua forest, but probably
also in lama-manele forest before the virtual disappearence of this
forest type on Oahu). The Oahu tree snail usually occurs at
elevations above 305 m (1,000 ft) where native species predominate.
Some evergreen forest land in which exotic species are dominate (guava
mixed forest) may also be inhabited by Achatinella. In poorly
drained areas (mountain bogs) Achatinella may also inhabit forested
wetlands (palustrine, broad-leaved evergreen forest and shrub/scrub).
Achatinella occurred ( and may still occur in a few locations) in
shrub and brush rangeland, in areas where non-native grasses have
invaded native evergreen forest (i.e., mixed ohia woodland with
grass); living snails may be found on isolated Metrosideros and other
suitable host trees and shrubs surrounded by grasses (09,27,41,62).
Habitat Associations - 1 (DRAFT) - Food Habits
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
HERBIVORE
LIFESTAGE FOOD FOOD PART
General Detritus
General Tree-Bark/Cambium
General Myxomycophyta
General Parasitic/Epiphytic Plants
General Detritus
General Tree-Bark/Cambium
General Myxomycophyta
General Parasitic/Epiphytic Plants
Food Habits - 1 (DRAFT) - Environment Associations
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Inland Wetlands: Bogs
G Coastal Features: Vegetated offshore islands
G Inland Wetlands: Bogs
G Coastal Features: Vegetated offshore islands
Environment Associations - 1 (DRAFT) - Life History
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
LIFE HISTORY
FOOD HABITS:
Observations of feeding in Achatinella are few. These snails are
usually nocturnal and graze leaf and bark surfaces for microscopic
algae, fungi, liverworts, and detritis, but apparantly do not feed
upon the leaves or bark themselves (26,41,62). The numerous
rastiform radular teeth of Achatinella are a characteristic shared
with all members of the family Achatinellidae (14), and these teeth
"apparently puncture and scrape loose the cells of the algal films
found on surfaces of leaves and twigs" (44). Gut contents of
A. mustelina and other species have been found to include "fungi,
often with shreds of fibers probably bark" (41), and gut contents of
the closely related Partulina confusa include fungi and algae (28).
No data is available regarding seasonal variation in feeding
activities or in availability of food supply.
HOME RANGE/TERRITORY:
Tree snails of the genus Achatinella are non-territorial but are
highly sedentary. Several authors have commented on the fact that
these snails may be found on a particular tree or shrub, year after
year, without venturing to neighboring plants of the same species
(27,28,41). The highly localized occurrence of particular color
patterns bears this out (see, for example, the various "subspecies"
of A. mustelina described by Welch (58)). These are arboreal snails
and apparently do not voluntarily visit the ground (41), but do crawl
freely from tree to tree (23); Henshaw (28) observed that they "can
travel 3.65 - 4.57 m (12-15 ft) over a tree in a single night".
Nevertheless, it is unlikely that the maximum linear dimension of the
home range of an individual snail would exceed a few tens of meters.
PERIODICITY:
O'ahu tree snails are generally nocturnal, although they may
become active during the day when moisture is available (27,41,62).
No seasonality in activity patterns has been observed, although
variation in the availability of moisture may be expected to have some
effect.
MIGRATION PATTERNS:
O'ahu tree snails are non-migratory.
COVER/SHELTER REQUIREMENTS:
During periods of inactivity, O'ahu tree snails seal to leaves,
branches, or trunks (occasionally in knotholes) of a variety of native
trees and shrubs and may also be found living on a few species of
non-native plants (particularly guava [Psidium] and kukui
[Aleurites]), but also other alien species). In general, there is no
strong preference among host plants, except that smooth-leafed plants
are preferred while pubescent plants are avoided (41).
REPRODUCTIVE SITE REQUIREMENTS:
Reproductive behavior of O'ahu tree snails has not been observed.
Presumably, these snails copulate and give birth in the trees and
Life History - 1 (DRAFT) - Life History
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
shrubs which are their usual activity and resting sites.
REPRODUCTIVE CHARACTERISTICS:
The breeding behavior of Achatinella has not been observed.
These snails are hermaphroditic and ovoviviparous (14,41); although it
has been claimed that these snails do not self-fertilize (26),
experimental evidence is lacking.
In a three-year field study of A. mustelina using the mark
recapture method, it was determined that attainment of reproductive
maturity required approximately 6.9 years, assuming that sexual
maturity coincides with formation of an expanded apertural lip and
cessation of further shell growth (23); a laboratory study of A. lila
produced an estimated 5.27 years for the time required to reach
maximum size (43). An age at maturity of 5-7 years is unusually long
for a land snail; although comparable data for other species are few,
most reach sexual maturity in one or two years (13,46). It has been
estimated that individuals of Achatinella may attain an age of 11
years (21), but the maximum age at which reproduction may occur is
unknown.
Dissected animals almost invariably contain a single embryo;
embryos are present at all times of the year, indicating that
reproduction is not seasonal (28,41). The length of gestation is
unknown. The annual fecundity rate has been estimated at 0.4
offspring per adult per year (23,62). A report that seven of
ten captive individuals of A. mustelina gave birth within a month
of collection (23,62) suggesting a higher rate. However, the
shock of collection could have caused the animals to give birth
prematurely, leading to an artificially high birth rate (this is
likely, as the smallest young died soon after birth). A second
estimate by Hadfield (21) is of 1-4 young per year.
PARENTAL CARE:
Parental care has not been observed in Achatinella.
POPULATION BIOLOGY:
Knowledge of the population biology of Achatinella is due
primarily to the careful studies of M.G. Hadfield of the University
of Hawaii (21,23). Further studies, in progress, will undoubtedly
yield valuable additional data. Population levels of Achatinella are
adversely influenced by a number of factors. Achatinella mustelina,
the only member of the genus for which a substantial body of data is
available, is characterized by late maturity (ca. 6 years to sexual
maturity), low fecundity (est. to be not more than 4 young per year
per adult), and relatively long potential life span (estimated at
ca. 11 years). In studies of wild populations about 35% of the
living snails observed were found to be of adult size
(distinguished by thickening of the lip (peristome) of the shell,
a normal indicator of sexual maturity in terrestrial pulmonates).
Using estimates of fecundity of from one to three young per
year per adult snail, Hadfield (21) estimated that the annual
survivorship required to support a stable population size ranges from
0.668 to 0.825. He noted that the life history traits he observed in
A. mustelina are characteristic of species subject to low levels of
Life History - 2 (DRAFT) - Life History
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
predation, and that as a consequence these snails are highly
vulnerable to extinction as a result of the suddenly increased
predation levels to which the activities of introduced predators and
human shell collectors have subjected them. Hadfield and Mountain
(23) estimated the population of their 25 m (82 ft) study plot at 210
living A. mustelina; Hadfield (21) shows that this modern population
density figure is much lower than those recorded by 19th centuary
observers. The degree to which management efforts can lead to
increased population densities is unknown.
SPECIES INTERRELATIONSHIPS:
Predation:
Published reports of predation on Achatinella or other Hawaiian
land snails by native animals are very scarce. Much of O'ahu's native
avifauna is now extinct, so estimates of avian predation on
Achatinella are highly speculative. Perkins (40) cites a report that
"slugs" (probably the land snail Succinea, according to Perkins) were
found in the gut of an O'ahu creeper (Paroreomyza maculata).
Phaeornis obscurus, the oma'o or Hawaiian thrush (extinct on O'ahu)
has been reported to feed partly on snails (56), and snails are a
major food item of Melamprosops phaeosoma, the po'ouli, a bird endemic
to Maui (05); neither has been observed to feed on Achatinella or
other achatinelline snails. The short-eared owl (Asio flammeus) and
the extinct Oahu o'o (Moho apicalis) have been identified as possible
predators on Achatinella (53), and it is probable that extinct geese,
rails, and ibises (39) may have included Achatinella in their diet,
to the extent that these arboreal snails were accessible to them.
Two doubtfully native invertebrates prey on Achatinella. Frick
(16) reported that Achatinella dislodged from their resting sites were
subject to predation by a ground-dwelling "centipede worm." The
flatworm, Geoplana septemlineata, has been demonstrated to be a
voracious feeder on ground-dwelling pulmonate snails in Hawai'i (36),
and often occurs in areas inhabited by Achatinella (09,21). Although
it is not known to ascend trees (21), Geoplana has been observed to
feed on Achatinella (reference to "small black worms" in ref. 27,10);
presumably, it attacks snails that have fallen to the ground after
becoming dislodged from their normal resting places in trees or
shrubs. Although Geoplana was described as endemic to Hawaii (31),
it has been suggested (19,21) that it is instead an alien species and
may have severely affected the native land mullusks of these islands.
Predation by rats and mice (particularly the roof rat, Rattus
rattus) has been cited by numerous observers as a serious threat to
the survival of Achatinella (02,03,19,21,25,26,27,40,47,53,54,62).
Predation by the introduced land snail Euglandina rosea is
universally regarded by malacologists and most others as a major
threat to the survival of Achatinella and other Hawaiian land snails
(19,21,22,23,25,26,27,29,30,33,34,35,37,44,53,54,55,62). Proponents
of the introduction of Euglandina to Hawai'i and other Pacific Islands
as a bio-control agent for Achatina fulica, the giant African snail,
have attempted to minimize the threat this predator poses to native
land snails (e.g. "Among the other possible biotic and physical
factors that contribute to the decline of the native snails,
Life History - 3 (DRAFT) - Life History
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
Euglandina at most played a minor role"(38)). "Before and
after" surveys of native snail populations likely to be impacted by
the spread of Euglandina rosea, were not conducted. Therefore,
experimental evidence necessary to defintively refute such claims.
A recent study (12) has carefully documented the devistating effect
this species is having on the endemic tree snails (Family Partulidae)
of Moorea, Society Islands and there is no reason to suspect that its
impact on Achatinella and other Hawaiian land snails has been less
catastrophic. Ironically, the effectiveness of Euglandina as a
bio-control agent for the giant African snail has yet been
demonstrated (08).
A number of other species of land snails (Gonaxis kibweziensis,
G. quadrilateralis, etc.) and insects (beetles, sciomyzid flies)
have been introduced to the Hawaiian Islands as bio-control agents for
the giant African snails and the exotic lymnaeid snails which are
intermediate hosts for the liver fluke, Fasciola gigantica; the
effects, if any, of these introductions on Achatinella are unknown
(35,37,55). Oxychilus alliarius, an alien carnivorous snail
established elsewhere in the State of Hawai'i but not yet on O'ahu,
could pose a threat to Achatinella if it reaches the island (42),
as may Vespula, an alien wasp now present in the State (18).
Parasitism:
Living Achatinella have been reported to be subject to parasitism
by the larvae of native flies of the genus Dyscritomyia
(Calliphoridae) (24,50), although the opinion has been expressed that
these flies are probably scavengers feeding on dead snails rather
than true parasites (40).
Larvae of the metastrongylid rat lung worm, Angiostrongylus
cantonensis, are parasitic in terrestrial mollusks and other
invertebrates in Hawai'i and elsewhere (01). Although Achatinella has
not yet been shown to serve as a host for this parasite,
Angiostrongylus has a low degree of host-specificity and has been
demonstrated to inflect a wide range of pulmonate snails, including
Euglandina rosea (57); rats are common in areas inhabited by
Achatinella, and it is probable that they are likewise subject to
parasitism by Angiostrongylus. Wallace and Rosen (57) found that, in
general, large snails are more likely to be infected with
Angiostrongylus larvae than are smaller snails, and carry more larvae
per individual than do smaller ones. Thus, the occurrence in
Achatinella habitat of large bodied alien land mollusks such as
Euglandina rosea, Limax maximus, and Meghimatium bilineatum may
increase the prevalence of Angiostrongylus infection among rats and
native snails, including Achatinella. The adverse effect of such
parasitisum is unknown, if indeed it does occur. At least one report
(21) doubts that parasitism by Angiostrongylus has significant impact
on Achatinella.
Disease:
Mead (37) has reported that a number of alien pulmonate species
in Hawai'i suffer from a disease characterized by the presence of
leucodermic skin lesions and apparently caused by the bacterium
Aeromonas hydrophila. Among the species affected are Bradybaena
Life History - 4 (DRAFT) - Life History
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
similaris (Bradybaenidae) and Subulina octona (Subulinidae), both of
which may occur in areas inhabited by Achatinella. Hadfield (21)
speculates on the possibility that this disease could account for
otherwise unexplained mortality in Achatinella populations studied by
him.
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 5 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Suppressing wildfire
Beneficial Restricting/regulating human disturbance of populations
Beneficial Controlling/Restricting Road Maintainance Actions
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Controlling/Restricting Pesticide Use
Beneficial Controlling/Restricting Herbicide Use
Beneficial Reforestation
Beneficial Restricting Timber Harvest
Beneficial Maintaining Later Stages of Succession
Beneficial Controlling/Removing Nonnative Vegetation
Beneficial Controlling/Removing Native Vegetation
Beneficial Stocking captive-reared wild-strain animals
Beneficial Transplanting wild animals
Beneficial Restricting Poaching
Beneficial Controlling/Restricting Noncommercial Harvest
Beneficial Controlling/Removing Invertebrates
Beneficial Controlling/Removing Exotic Vertebrates
Beneficial Controlling/Removing Feral Animals
Adverse Incidental Capturing/Killing
Existing Incidental Capturing/Killing
Adverse Artillery/Explosions
Existing Artillery/Explosions
Adverse Poaching
Existing Poaching
Adverse Collecting
Existing Collecting
Adverse Commercial Exploitation
Existing Commercial Exploitation
Adverse Hiking/Camping
Existing Hiking/Camping
Adverse Climate Alteration
Existing Climate Alteration
Adverse Inherent Reproductive Characteristics
Existing Inherent Reproductive Characteristics
Adverse Disease
Existing Disease
Adverse Parasites
Existing Parasites
Adverse Predation
Existing Predation
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Transmission Lines/Towers
Existing Transmission Lines/Towers
Adverse Soil compaction by heavy equipment in mine areas
Existing Soil compaction by heavy equipment in mine areas
Adverse Reservoirs
Management Practices - 1 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
RESULT MANAGEMENT PRACTICE
Existing Reservoirs
Adverse Applying herbicides
Existing Applying herbicides
Adverse Applying pesticides
Existing Applying pesticides
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse Grazing
Existing Grazing
Adverse
Existing
Adverse Vegetation Composition Changes
Existing Vegetation Composition Changes
Adverse Fire
Existing Fire
Adverse Forest Alteration
Existing Forest Alteration
Adverse Harvesting
Existing Harvesting
Beneficial Suppressing wildfire
Beneficial Restricting/regulating human disturbance of populations
Beneficial Controlling/Restricting Road Maintainance Actions
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Controlling/Restricting Pesticide Use
Beneficial Controlling/Restricting Herbicide Use
Beneficial Reforestation
Beneficial Restricting Timber Harvest
Beneficial Maintaining Later Stages of Succession
Beneficial Controlling/Removing Nonnative Vegetation
Beneficial Controlling/Removing Native Vegetation
Beneficial Stocking captive-reared wild-strain animals
Beneficial Transplanting wild animals
Beneficial Restricting Poaching
Beneficial Controlling/Restricting Noncommercial Harvest
Beneficial Controlling/Removing Invertebrates
Beneficial Controlling/Removing Exotic Vertebrates
Beneficial Controlling/Removing Feral Animals
Adverse Incidental Capturing/Killing
Existing Incidental Capturing/Killing
Adverse Artillery/Explosions
Existing Artillery/Explosions
Adverse Poaching
Existing Poaching
Adverse Collecting
Existing Collecting
Adverse Commercial Exploitation
Existing Commercial Exploitation
Adverse Hiking/Camping
Existing Hiking/Camping
Management Practices - 2 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
RESULT MANAGEMENT PRACTICE
Adverse Climate Alteration
Existing Climate Alteration
Adverse Inherent Reproductive Characteristics
Existing Inherent Reproductive Characteristics
Adverse Disease
Existing Disease
Adverse Parasites
Existing Parasites
Adverse Predation
Existing Predation
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Transmission Lines/Towers
Existing Transmission Lines/Towers
Adverse Soil compaction by heavy equipment in mine areas
Existing Soil compaction by heavy equipment in mine areas
Adverse Reservoirs
Existing Reservoirs
Adverse Applying herbicides
Existing Applying herbicides
Adverse Applying pesticides
Existing Applying pesticides
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse Grazing
Existing Grazing
Adverse
Existing
Adverse Vegetation Composition Changes
Existing Vegetation Composition Changes
Adverse Fire
Existing Fire
Adverse Forest Alteration
Existing Forest Alteration
Adverse Harvesting
Existing Harvesting
COMMENTS ON MANAGEMENT PRACTICES -
The extinction or depletion of populations of the land snail,
genus Achatinella, is the result of many causes acting over an
extended period of time. This process began with the activities of
the prehistoric Polynesian settlers of these islands (11,32), and has
accelerated since the European rediscovery of Hawai'i in 1778. As
early as the mid-1850's local naturalists were noticing the
disapperance of populations of Achatinella (16), and several recent
works (19,21,25,26,27,33,34,53,54) have presented discussions of the
conservation status of Achatinella and other native land snail in
Hawaii. An extensive discussion of preservation of Hawaiian
terrestrial ecosystems is provided by Stone and Scott (48).
The effects of forest clearing, forest alteration, vegetation
Management Practices - 3 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
composition changes, agricultural development, grazing, and exotic/
feral/introduced species (mammalian herbivors) are closely
interrelated. The agricultural activities of the prehistoric
Polynesians undoubtedly caused destruction of lowland forests
inhabited by Achatinella (11,21,26,27,32,62), although it is difficult
to differentiate impacts of pre-contact human activities from those
after European rediscovery of the Hawaiian Islands in 1778. Post
contact destruction of forests was hastened and extended to higher
elevations as a result of land clearance for agriculture or timbering
operations (03,25,26,27,33,34,53,54) and the introduction of cattle
and other mammalian herbivores in the late 1700's (03,16,21,25,26,27,
33,41,62). Ecological disturbance due to the activities of humans and
feral mammals (particulary pigs) favors the spread of alien (exotic,
non-native) plant species such as Clidemia creating conditions
unsuitable for Achatinella (25,26,27,33,48,53,54,62). Disturbance
encourages growth of extensive thickets of native uluhe fern,
Dicranopteris, believed to be disadvantageous to Achatinella (27,33,
53,54).
Fire kills individual snails and degrades tree snail habitat.
Alien plant species invade burned areas making these unsuitable for
recolonization by native snails; the sedentary nature of the O'ahu
tree snail makes recolonization a slow process under the best of
conditions (07,10,26,27,53,54,62). Hiking (10,27,53,54) and military
training exercises (i.e. artillery explosions at firing ranges at
Makua Valley and Schofield Barracks (10,26,27,54,62)) may increase the
likelihood of destruction due to fire.
Construction projects (i.e. roads/highways) and associated heavy
equipment use in areas inhabited by Achatinella are a threat. The
destruction of one colony by construction of a plantation reservoir
has been reported (21). Land clearance for helicopter pads and
electric power transmission lines may also kill snails (15,54). A now
abandoned Nike missile site above Makua Valley, Wai'anae Mountains,
was built at a site formerly supporting Achatinella, and construction
of roads such as that providing access to Air Force and Federal
Aviation Administration facilities on Mt. Kaala could displace tree
snail colonies (distribution data from Welch (58)).
Climatic change; reductions in rainfall and moisture
availability, has been identified (33,34,41) as a cause of extinction
in Achatinella, although the deforestation said to be responsible for
this climatic change would itself be a likely cause of tree snail
extinctions.
Introduced predators (i.e. Rattus rattus) have undoubtedly been
critical in historic-era extinctions of Achatinella (02,03,17,19,21,
25,26,27,40,47,53,54,62). Euglandina rosea, a predatory snail
imported from Florida in 1955, in an effort to control the giant
African snail (Achatina fulica), is undoubtedly an important recent
factor (17,19,20,21,22,23,25,26,27,29,30,33,34,44,53,54,55,62). The
effects, if any, of other bio-control agents (streptaxid snails of the
genus Gonaxis and sciomyzid flies) are unknown. Geoplana
septemlineata, a terrestrial flatworm, has been observed to feed on
Achatinella (10,27), and the presence of Euglandina (54) and other
alien land mollusks in areas inhabited by Achatinella may lead to
increased abundance of Geoplana (19,21). Geoplana has been considered
Management Practices - 4 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
to be a native to Hawai'i (54), but the belief exists that it may not
be native (19,21). Ants have been identified as an important predator
on Hawaiian land snails and other native invertebrates (45,63), but
no observations of ant predation on Achatinella are available (21,62,
63).
Parasitism by Angiostrongylus cantonensis, the rat lung-worm
(Nematoda), may possibly occur in Achatinella (19) since this parasite
infects a broad range of terrestrial and freshwater mollusks (57);
there are doubts as to its importance in Achatinella, however (21).
A disease caused by the bacterium Aeromonas hydrophila has been
observed to cause death in several non-native land snail species in
Hawaii (35,37) and has been cited (21) as a possible cause for
otherwise unexplained mortality in Achatinella populations.
The low reproductive rate of Achatinella and the unusually long
period these snails require to reach sexual maturity is an important
factor rendering these snails extremely vulnerable to extinction under
unnaturally high predation rates (21,23,27,33,53,54,62). Their
limited geographic range is another condition prediposing them to
extinction (19,53,54,62).
Collecting (19,21,25,26,27,33,34,53,54,62) and commercial
exploitation (54) were formerly important in extirpation of
Achatinella populations, although losses to these causes are much
less now than before ca. 1940, when tree snail collecting was a
popular hobby.
Although most current Achatinella habitat is located within
designated Forest Reserves or other Conservation District lands,
regulated by the State of Hawai'i, Board of Land and Natural Resources
(BLNR), and Department of Land and Natural Resources (DLNR), competing
land uses are often given higher priorities than preservation of
native wildlife in management of these lands. Hart (26,27) has noted
how State responsiveness to pressures from hunters, desiring continued
maintenance of large stocks of feral animals (particularly pigs),
causes damage to the forests necessary for survival of Achatinella.
Inadequate quarantine procedures and regulations regarding intentional
introductions of bicontrol and other alien species is also a factor
(29).
The proposed Tri-Fly Eradication Program (52,54,62) poses a
potentially serious threat to Achatinella (i.e. use of pesticides
and the eradication of guava trees (a fly host tree).
Approximately 80% of the human population of the State of
Hawai'i lives on the Island of O'ahu, and future population increases
will lead to additional use of Oahu's limited forested areas and
pressure for their development (53,54). Potential threats include
activites that would change land use or vegetation type, making
these areas unsuitable habitat, and the introduction of alien
predators or parasites. On other islands, native forest similar to
Oahu's Achatinella habitat is currently threatened by woodchipping
operations, conversion to agricultural use (biomass production,
pasture, timber, or tree crops such as macadamia nuts). Any
proposals for construction projects should be carefully
scrutinized for possible impact. Any introductions of predators of
snails should be prevented, as well as introduction of alien plant
species capable of invading native forests. Other possible threats
Management Practices - 5 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
include : (1) introduction (to O'ahu (06)) of Oxychilus alliarius (an
exotic canabalistic snail) (now effecting other populations on Hawai'i
and Maui (42)); (2) introduction of parasitic calliphorid flies
(Melinda pusilla is already on O'ahu (23)) may impact the tree snail;
and (3) their specialized feeding habits make the snail vulnerable to
availability or suitability of this resource (depletion or
modification due to pollution and spread of alien species, etc.).
UNAPPROVED PLAN
No recovery plan has been written for the O'ahu tree
snails. Recommendations for their protection can be found in: An
Archival Survey of the Endangered O'ahu Tree Snail (Genus Achatinella)
on U.S. Army Support Command, Hawai'i, Installations. Rep. prep. by
Dr. Carl C. Christensen for the Dept. of the Army Corps of Eng.
A large number of factors have caused the decline of
O'ahu tree snails. Also, gaining access to, and getting around in their
habitat is difficult. Therefore, recovery recommendations must
emphasize the prevention of future problems that are likely to arise
for the snails in their habitat. Recovery tasks attempting to undo
past harm will be a much greater challenge.
Stepdown outline recommended for Recovery:
(1) Prepare Recovery Plan: Problems affecting tree snails are poorly
understood or appreciated by those responsible for resource
management, largely because of the unavailability of recovery
guidelines. The top priority for the tree snails' protection should
be the development of a recovery plan.
(2) Surveys (to assess status of populations): Populations of
tree snails are very localized within a large expanse of difficult,
forested terrain. Also, many species and subspecies are involved.
Therefore, the determination of locations and sizes of the tree
snail populations is crucial to the formulation of recovery
priorities. Surveys for tree snails should be required as part of
the environmental review process for development and construction
projects scheduled or proposed for habitat within the historic range
of tree snails (i.e., road maintenance/construction, and development).
(3) Research (on population biology of tree snails): An understanding
of life history parameters, reproduction, foraging behavior, effects
of predation and parasitism, and other aspects of the population
ecology of O'ahu tree snails is required to further clarify recovery
needs. Studies of the population biology of tree snails, conducted
now principally by Dr. M. Hadfield of the University of Hawai'i,
deserve continued support, and new research is encouraged.
(4) Habitat Preservation: Virtually all snail populations occur on
lands zoned by the State as Conservation lands and as Forest Reserves,
affording the snails and their habitat considerable protection. The
natural integrity of this habitat should be maintained on these lands
(i.e., maintain later stages of natural succession, revegetate or
rehabilitate disturbed areas to a natural state, and monitor and
control land use zoning), and development should be strictly
controlled through Section 7 consultation, other forms of
Management Practices - 6 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
environmental review, and the land use permitting process. Projects
creating disturbance within native forest are particularly important.
Land clearance (for development and for timber harvesting),
construction projects, reforestation (i.e., plantings of conifers,
eucalyptus, and other alien trees), and flooding associated with dams
all contribute to the piece-meal loss of habitat and to the further
incursion of detrimental effects. Alien plants, in particular can
expand beyond the bounds of the project site. Proposals for pesticide
and herbicide projects, such as the "Tri-Fly" eradication program,
should be critically reviewed for their impact on tree snails and
their habitat.
(5) Prevention of Forest Fires: During droughts, Hawaiian forests
become inflammable, particularly in the extensive areas dominated by
the 'uluhe fern. Besides cremating whole colonies of tree snails,
these fires maintain and promote the spread of fire adapted plants,
such as 'uluhe, and cause detrimental changes in snail habitat that
are difficult to reverse. The State and U.S. military should place
high priority in preventing and controlling fire.
Dramatic changes in species composition of Hawaiian forests
have resulted from the spread of alien plants and the 'uluhe fern.
Much new habitat is inhospitable to tree snails. Populations of
these plants should be reduced through carefully planned and
implemented biological control and fire prevention programs.
(6) Prevent Further Importations of Potentially Noxious Alien Plants
and Animals: Virtually all of the intractable problems plaguing
recovery programs for endangered species (including the O'ahu tree
snails) in Hawai'i, stem from the introduction of alien organisms
(i.e., feral animals, plants, parasites, or diseases). The tree
snails now must adapt to new sources of predation and parasitism and
to new host plants. Other noxious organisms will undoubtedly find
their way to these islands. Preventing their arrival should be a high
priority for all resource managers. Strict inspections of incoming
ships and planes, strict permitting of allowable importations, and
requiring of Enivironmental Impact Statement, or other outside review
processes for releases of biological control organisms have been
recommended to prevent potential problems. Lethal introductions,
such as the deliberate importation and spread of Euglandina rosea
to control the Giant African snail (Achatina fulica), must be
prevented.
(7) Coordinating Recovery Planning and Implementation with the U.S.
Military: Certain conservation lands controlled by the military are
used for low over-flights in the training of helicopter pilots,
jungle training of ground troops, and other activities. Cooperation
with the military should be sought to minimize the impact of these
activities on tree snail habitat.
(8) Control Alien Predators and Parasites: At least three species of
predatory snails, several snail parasites, and roof rats (Rattus
rattus) have been identified as important possible sources:
nevertheless, control measures should be sought and implemented if
found.
(9) Control Feral Pigs: Feral pig "rooting" activities seriously
degrade native forests. Though not a direct threat to tree snails,
such irreversible alteration to tree snail habitat will inevitably
Management Practices - 7 (DRAFT) - Management Practices
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
lead to further declines in tree snail populations.
(10) Control Collecting/Poaching: Measures should be undertaken to
prevent any further commercial and private collecting (i.e., poaching)
of tree snails for their brightly colored shells.
(11) Captive Breeding/Translocation: These measures should be
considered as possible options for species with minimal chances for
recovery.
At present, there is no recovery program for the O'ahu tree
snails, though current research and various environmental practices
indirectly benefit these animals.
Management Practices - 8 (DRAFT) - References
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Allicata, Joseph E., and K. Jindrak. 1970. Angiostrongyliasis in
the Pacific and Southeast Asia. Charles C. Thomas, Springfield,
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02 Atkinson, I.A.E. 1977. A reassessment of the factors,
particularly Rattus rattus L., that influenced the decline of
endemic forest birds in the Hawaiian islands. Pac. Sci. 31:
109-133.
03 Baldwin, D.D. 1877. Land shells of the Hawaiian Islands. HI.
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04 Baldwin, D.D. 1893. Catalogue, land and fresh water shells of
the Hawaiian Islands. Press Publ. Co., Honolulu, 25 pp.
05 Baldwin, Paul H., and Tonnie L. Casey. 1983. A preliminary list
of foods of the Po'o-uli. Elepaio 43:53-56.
06 Bernice P. Bishop Museum, Dept. of Zool. Unpubl. collection
records.
07 Christensen, Carl C. 1983. An archival survey of the endangered
Oahu tree snail (Genus Achatinella) on U.S. Army Support Command,
Hawaii, Installations. Unpubl. Rpt. prepared for: Dept. of the
Army, Corps of Eng., Pac. Ocean Div., Honolulu, HI. iii +
22 pp. + app. A1-A11.
08 Christensen, Carl C. 1984. Are Euglandina and Gonaxis effective
agents for biological control of the giant African snail in Hawaii.
Am. Malacol. Bull. 2:98-99 [abstract].
09 Christensen, Carl C. Unpubl. obs. Honolulu, Hawaii.
10 Christensen, Carl C., and Michael G. Hadfield. 1984. Field
survey of endangered Oahu tree snails (Genus Achatinnella) on the
Makua Military Reservation, Oahu, Hawaii. Unpubl. report for:
U.S. Army Corps of Eng., Pac. Ocean Div. 20 pp.
11 Christensen, Carl C., and Patrick V. Kirch. 1986. Nonmarine
mollusks and ecological change at Barbers Point, O'ahu, Hawai'i.
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12 Clarke, Bryan, James Murray, and Michael S. Johnson. 1984. The
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13 Comfort, A. 1957. The duration of life in mulluscs. Proc.
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14 Cooke, C. Montague, Jr., and Yoshio Kondo. 1960. Revision of
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5 pp. + 3 tables + app.
18 Gagne, Wayne C. 1985. Pers. comm. Bernice P. Bishop Mus.
References - 1 (DRAFT) - References
Species SNAIL, TREE, OAHU
Species Id ESIS351001
Date 13 MAR 96
Honolulu, HI.
19 Gagne, Wayne C., and Carl C. Christensen. 1985. Conservation
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21 Hadfield, Michael G. 1986. Extinction in Hawaiian achatinelline
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22 Hadfield, Michael G., and E. Alison Kay. 1981. The multaple
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23 Hadfield, Michael G., and Barara Shank Mountain. 1980. A field
study of a vanishing species, Achatinella mustelina (Gastropoda,
Pulmonata), in the Waianae Mountains of Oahu. Pac. Sci. 34:
345-358.
24 Hardy, D. Elmo. 1981. Diptera: Cyclorrhapha IV, series
Schizophora, section Calyptratae. Insects of Hawaii. 14, vi +
491 p.
25 Hart, Alan D. 1975. Living jewels imperiled. Defenders 50(6):
482-486.
26 Hart, Alan D. 1978. The onslaught against Hawaii's tree snails.
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Hawaiian tree snail genus Achatinella (Swinson) fro Oahu. Unpubl.
report for: U.S. Fish & Wildl. Ser., Off. End. Spec. 25 pp.
28 Henshaw, H.W. 1913. Observations on Hawaiian Achatinellidae. Pp.
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29 Howarth, Francis G. 1983. Classical biocontrol: panacea or
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30 Howarth, Francis G. 1985. Impacts of alien land arthropods and
mollusks on native plants and animals in Hawaii. In: C.P.
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31 Hyman, Libbie H. 1939. Land planarians from the Hawaiian Islands.
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32 Kirch, Patrick V. 1982. The impact of the prehistoric Polynesians
on the Hawaiian ecosystem. Pac. Sci. 36:1-14.
33 Kondo, Yoshio. 1970. Extinct land molluscan species. Unpubl.
report to: Colloquim on Endangered Species of Hawaii. 8 pp.
34 Kondo, Yoshio. 1980. Endangered land snails, Pacific. Unpubl.
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35 Mead, Albert R. 1961. The giant African snail: a problem in
economic malacolgy. Univ. of Chicago Press. xvii + 257 pp.
36 Mead, Albert R. 1963. A flatworm predator of the giant African
snail Achatina fulica in Hawaii. Malacologia 1:305-311.
37 Mead, Albert R. 1979. Economic malacology with particular
reference to Achatina fulica. Vol. 2B, pp. 1-150., In: V. Fretter
and J. Peake, eds., Pulmonates, Academic Press, London.
38 Nakao, Harry. 1974. Comments re-proposed regulation against
Euglandina rosea. Unpubl. memo. for: Chief Plant Inspector, Dept.
References - 2 (DRAFT) - References
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Species Id ESIS351001
Date 13 MAR 96
of Ag., HI. 3 pp.
39 Olson, Storrs L., and Helen F. James. 1982. Prodromus of the
fossile avifauna of the Hawaiian Islands. Smith. Cont. to Zool.,
no. 365, 59 pp.
40 Perkins, R.C.L. 1913. Introduction. In: D. Sharp, ed., Fauna
Hawaiiensis, vol. 1:xv-ccxxviii. Cambridge Univ. Press, Cambridge.
41 Pilsbry, Henry A., and C. Montague Cooke, Jr., 1912-1914.
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428 pp., 63 pls.
42 Severns, Mike. 1984. Another threat to hawaii's endemics. HI.
Shell News 32(12):1,9.
43 Severns, R.M. 1981. Growth rate determinations of Achatinella
lila, a Hawaiian tree snail. Nautilus 95:140-144.
44 Solem, Alan. 1974. The shell makers: introducing mollusks. John
Wiley and Sons, New York. xiii + 289.
45 Solem, Alan. 1976. Endodontoid land snails from the Pacific
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46:3178-3182.
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Mountains, Oahu. Bernice P. Bishop Mus. Bull. 152. 164 pp.,
13 pls.
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Range, Oahu. Smithsonian Misc. Coll. 103:1-236.
18 Welch, d'Alte A. 1954. Distribution and variation of the
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and northern slopes of the Koolau Range, Oahu. Proc. Acad. Nat.
Sci. Philad. 106:63-107.
19 Welch, d'Alte A. 1958. Distribution and variation of the
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slope of the Koolau Mountains, Oahu. Proc. Acad. Nat. Sci.
Philad. 110:123-212.
References - 5