establishment of the invasive white-tailed deer in...
TRANSCRIPT
1
Establishment of the Invasive White-tailed Deer in Portland, Jamaica
By: Shauna-Lee Chai
Conservation Science Officer
Jamaica Conservation & Development Trust
29 Dumbarton Avenue, Kingston 10. Jamaica W.I.
Summary
A small population of white-tailed deer (Odocoileus virginianus) was introduced to Jamaica in the 1980s through
the accidental release of captive-held animals. This article is based on a 2003 investigation carried out on their
distribution, population size, and socioeconomic impacts of the introduction. The investigation also sought to
ascertain whether the deer represent a threat to biodiversity in the remaining natural forests of the Blue and John
Crow Mountains.
O. virginianus in Jamaica is restricted to Portland, where it occupies a relatively small area of approximately 19
km2 in and around the communities of Mt. Pleasant, Industry, Shrewsbury, Content, Darley, Little Spring
Garden, Eden Wood, Paradise, and, Swift River. These areas are characterized by low altitudinal edge habitat
interspersed with small agricultural fields growing cash crops like pumpkin, carrot, yam, and corn.
Interviews with local residents indicate that O. virginianus is a serious agricultural pest in the communities in
which it occurs. Farmers in the area complained of deer damaging agricultural crops, and claimed average monthly
losses of J$10,000.
By incorporating deer defaecation rate and dung decay rate into line transect surveys of deer dung, the total deer
population in Portland was estimated at 182 individuals.
This alien invasive does not appear to have penetrated the forests of The Blue and John Crow Mountains, and at
present, poses more of a threat to small scale agriculture.
Key-words: Odocoileus virginianus, alien invasive, deer dung transects, agricultural pest, introduced
species
2
Introduction
One of the greatest challenges facing wildlife professionals, and indeed, native ecosystems world
wide, is the increasing rate at which human activities are causing a homogenization of the earth’s
species. Jamaica is no exception to this unfortunate trend, and it is threatened by 52 known
invasive plant and animal species (IABIN, 2003).
Introduced species cause billions of dollars in damages each year. Their impacts include
herbivory, predation, disease, parasitism, competition, habitat destruction, and hybridization with
native species (Simberloff, 2000). The devastating effects of biological invasions are rivaled only
by habitat destruction, with the latter being the greatest cause of species decline (Wilson, 1992).
Island systems are especially vulnerable to exotic species, due in large part to the absence of
entire groups of species in insular communities (e.g. terrestrial mammals); hence island invaders
may encounter resource rich environments that are free from competitors and predators, and
such ecological release greatly enhances their prospects for successful establishment (Simberloff
1995).
Odocoileus virginianus Species Description
Odocoileus virginianus Z. (white-tailed deer) is the most widespread and abundant member of the
deer family (Cervidae). There are approximately 38 subspecies of O. virginianus recognized in
America (Smith, 1991). White-tailed deer are so named because when alarmed, they hold their
tails erect, exposing their white underside. Adult males weigh from 90-135 kg, and attain a height
(at shoulder) of 53.3-106.7 cm, and a length of 104.1-240 cm. The length of the tail averages 10-
36.5 cm, and the hind foot averages 27.9-53.8 cm in length. In general, females weigh 20-40%
less than males (Taylor, 1956).
In the northern hemisphere, this species demonstrates seasonal variation in pelage. Their
summer coat consists of short, thin, wiry hairs and varies from red-brown to bright tan. The
coat is darker along the mid-dorsum and paler on the face, throat and chest. The winter coat
develops in late summer to early autumn, and is a blue-gray to gray-brown colour with longer,
thicker, and more brittle hairs. Adults have a white nose-band, orbital region, and throat patch.
The underparts, including the lower tail, insides of legs, venter, and chin are also white (Guthrie,
3
1971). Fawns have a red-brown coat, with white dorsal spots that disappear at 3-4 months of
age (Hesseleton and Hesseleton, 1982).
Adult males possess antlers (rarely found on females), and male fawns have small bumps or
“buttons” in their first year, and unbranched spikes or branched antlers thereafter. The size and
shape of antlers is a reflection of age, nutrition, heredity and heterozygosity (Hesseleton and
Hesseleton, 1982).
Reproductive Capacity
Deer have very high rates of reproduction, and given optimum conditions and low mortality
rates, their populations can expand rapidly. McCullough (1979) reported that a population of 6
white-tailed deer (2 bucks and 4 does presumed to be pregnant) introduced to the Edwin S.
George Reserve, a 1,146 acre reserve in southeastern Michigan, grew to a size of 180 individuals
in six reproductive seasons (6 years), and reached a maximum of about 222 head in 7 years.
Later, the population was reduced to 10 deer, and in a period of 6 years, it grew to a size of 212
individuals. The population growth rate in these examples was found to be over 50% per year
(McCullough, 1983). Although remarkable, this population growth rate was not thought to
represent the maximum rate of increase attainable by the population, as the growth rate of the
herd decreased with increasing population size. An unimpeded rate would have yielded over 300
individuals, compared to the estimated 222 and 212 (McCullough, 1982).
In addition to their high reproductive capacity, white-tailed deer are among the most genetically
variable mammals studied, and this high genetic variability is very advantageous, especially when
a small number of these animals are introduced to an area, as it reduces the magnitude of
potential founder effects.
Natural Range and Habitat Preference
White-tailed deer range from southern Canada throughout most of the coterminous United
States, southward to northern South America (Smith, 1991). The animal has been introduced to
many places, including The British Isles, Czechoslovakia, Finland, Yugoslavia, New Zealand,
Cuba, The Virgin Islands, Curacao, and other Caribbean islands.
Deer prefer ecotone or edge habitats where fields and forests come together, producing an area
with abundant shrubs and low growing trees. This habitat provides them with adequate
4
vegetation for concealment and ample food; deer tend to avoid mature forests where the
undergrowth, and hence food supply, is limited (Severinghaus and Cheatum, 1956). Radio-
teleometry studies in Scotland showed that deer used agricultural land primarily at dusk and
dawn, and woodland areas were highly preferred in between these times (during the day and at
night) (Idris, 1990).
Deer Impacts
Both native and introduced deer are considered pests in many parts of the world. Deer are
known to pose a threat to native forests (Marquis & Brenneman 1981, Kay 1993, Relva &
Veblen 1998, Manchester & Bullock 2000, Wardle et al. 2001, & Fuller & Gill 2001). Through
predation of seeds, browsing, and trampling of seedlings, deer may exert a profound negative
impact on forest regeneration. Deer also damage forests through browsing of the lateral
branches or terminal buds of developing trees, bark-stripping of more mature trees, and fraying
of bark from the main stem of small trees by rubbing them with their antlers (Putman and
Moore, 1998).
In Pennsylvania, the disappearance of highly palatable plants was found to adversely affect other
wildlife that rely on these plants for food and cover, resulting in a dramatic reduction of
biodiversity in forests. deCalasta (1994) found that deer altered forest structure and composition
by eliminating much of the intermediate canopy, which led to the local extinction of many
intermediate canopy dwelling songbirds.
In its native range within the United States, for example, O. virginianus is a serious agricultural
pest. Because of their large size and associated dietary needs, these ruminants are able to
consume virtually all the foliage of the plants they prefer (Nugent, 2001). White-tailed deer
allocate more time to feeding than to any other activity, and select the most nutritious forage
available (McCullough, 1982).
In agricultural areas, farm crops are an important year-round source of high quality forage for
white-tailed deer, representing up to 78% by mass of the total diet (Gladfelter, 1984). As a
result, deer can pose a serious threat to agriculture, and can inflict considerable economic losses.
Damage to farmland occurs in many forms, including grazing, flattening by rolling, lying, or
trampling of crops, damage to fences or hedges, and damage to trees (Scott and Palmer, 2000).
Doney and Packer (1998) report from a survey carried out in lowland England that the most
5
common type of damage was grazing, followed by damage to trees, flattening of crops, and
damage to fences.
Conover et al. (1995) estimated crop damage in the United States agriculture industry at almost
US$500 million per annum, and deer are responsible for much of these damages. In one survey
conducted by the Pennsylvania Farm Bureau (2002), the average farmer lost over US$9,000 per
year due to damages caused by deer.
Deer also affect the water quality of river systems through erosion and faecal contamination, and
they carry diseases and parasites which can be transmitted to humans.
About 29,000 people are injured and over 200 people die each year due to deer-vehicle collisions
in the U.S. (Conover, 1995).
Deer Introduction to Jamaica and its Implications for Biodiversity Conservation
The white-tailed deer was introduced to the island in the 1980’s. There are conflicting reports
about the year and the number of deer that were introduced. One confirmed report is that in
1988 during hurricane Gilbert, 6 captively held deer escaped into the wild from their holding at
Somerset Falls - a local tourist attraction in the parish of Portland. These 6 individuals were
comprised of 3 males and 3 females (Shaw, pers. comm.). There was, however, probably more
than one instance of deer escaping from this location, as residents in the area maintain that some
of the animals escaped in 1980 during hurricane Allen.
The Blue and John Crow Mountains National Park is located in relatively close proximity to
areas where white-tailed deer have now become established. Jamaica has been recognised as a
biodiversity hotspot, and much of its biodiversity is contained within this park. The park is the
largest remaining area of natural primary forest, and contains some 923 endemic species of
vascular plants (NEPA, 2003). The area also serves as an important watershed that is vital for
the water supply to the eastern end of the island, including Kingston. The possible penetration
of O. virginianus into these forests is cause for considerable concern.
The already threatened state of the Blue and John Crow Mountain forest, due to charcoal
burning and hillside farming renders this ecosystem more invasible, and coupled with these pre-
6
existing threats, the establishment of an introduced herbivore like the white-tailed deer could
have serious implications for biodiversity conservation in the area.
Study area
This study was conducted near the centre of Portland, about 8 km west of the capital Port
Antonio. The area is approximately 20 km2, and is characterized by ecotone or edge habitat,
interspersed with agricultural land (Figure 2.1). Many of the farms in the area are small (<0.5
km2), and do not show up on the land use map in Figure 2.1.
Altitude ranged from 50 m near the Swift River to 350 m on surrounding hilltops. There are
some areas of secondary forest containing native trees and climbers like Zygia latifolia and Entada
gigas respectively, while other areas are covered by introduced species of bamboo (Bambusa
vulgaris), fern (Nephrolepis sp) and pine trees (Pinus caribea) (Plate 2.1). Much of the area is under
cultivation, with carrot, pumpkin, banana, yam, and cocoa being the predominant crops.
The parish of Portland receives an average of 367 cm of rainfall per year, and 27.8 cm of rainfall
in the month of June (Meteorological Service of Jamaica, pers comm., 2003). Numerous
watercourses like the Swift River, Daniels River, Kelly Brook, and the Black River permeate the
area, and there are several small farming communities along the roads. The study was
concentrated in and around the communities of Content, Mt. Pleasant, and Shrewsbury, as these
communities appeared to contain the highest densities of the introduced deer.
7
8
METHODS
Field work for the study was carried out in the summer months of June and July, 2003. Visits
were made to communities within Portland where deer presence had been reported. Initially,
surveys were conducted over a broad area in order to map the full extent of the distribution of
O. virginianus (Figure 2.1). Subsequent surveys and field work were conducted in areas
identified as containing deer. A questionnaire was administered to community members
(concentrating on farmers), and using this method, the presence of deer, and their impacts in
different communities were ascertained. Deer abundance was estimated using line transect
surveys of deer dung, as described by Buckland (1993).
RESULTS
Odocoileus virginianus distribution
Survey results show that deer are present on the outskirts of the following communities: Mt.
Pleasant, Shrewsbury, Content, Darley, Little Spring Garden, Eden Wood, Industry, Paradise and
Swift River (Figure 4.1). The animals were found to occupy a total area of approximately 19
km2, but they were not distributed evenly over this area, as there were core areas with relatively
high density, and areas where only occasional sightings were recorded.
9
Figure 4.1 Study area showing survey points and area occupied by white-tailed deer in
Portland
10
Twenty eight farmers and thirty two other residents, within the area occupied were interviewed.
Many people living in towns or larger communities within the area occupied by O. virginianus had
never heard of deer occurring in Portland; and, as expected, farmers were the most
knowledgeable about the animals, as they had had the most encounters with the creatures
through crop raiding (Figure 4.2).
0
10
20
30
40
50
60
70
80
90
100
farmer other
some knowledge of deerin Portland
no knowledge of deerpresence in Portland
Figure 4.2 Percentage of farmers and other survey respondents within the area occupied by O.
virginianus who had knowledge of deer presence in Portland
Crop Damage
Farmers reported deer in their crops at dusk and especially at dawn. Herd size according to
farmers is 2-3 individuals, often consisting of a doe, and one or two fawns. This is the
characteristically small herd size of Odocoileus (Anderson & Wallmo, 1984). Grazing damage was
the only type of perceived damage reported by farmers. They complained that crop damage
from deer has escalated in the past 5-6 years, and estimate loosing on average $10,000 per farmer
per month from crop damage due to deer. Crops that received the most damage include
pumpkin, carrot, yam, okra, pepper, peas, and corn (Figure 4.3). Crops like banana, plantain,
coco, and dasheen were generally not taken during deer raids. For some crops such as carrot and
pumpkin, only a few bites of individual fruits are taken, and many more crops are damaged than
are actually consumed. As a consequence, deer are able to destroy entire fields of crops
overnight. Such extensive damage can apparently overwhelm small-scale agricultural operations,
11
as some small farmers have reportedly gone out of business as a direct result of losses
attributable to deer (Plates 4.1 & 4.2).
Figure 4.3. Chart showing crop types preferred by deer according to the number of farmers that
reported damages in particular crop types. This pattern probably reflects both the availability of
various crops and deer crop preference.
To deter deer from raiding crops, farmers have employed a number of measures. Some have
hung makeshift scarecrows sprayed with perfume in their plots (Plate 4.3). Others have rubbed
the fence posts surrounding their crops with bath soap, hoping that the scent will deter raiders.
And some farmers have left lit lanterns burning in their plots overnight.
Plate 4.1. Farmer from the community of Content showing damage to pumpkin by white-tailed
deer
23
22
11
8
65
pumpkin
carrot
yam (foliage)
corn
pepper (foliage)
peas
12
Plate 4.2. Only a few bites of individual immature pumpkins were taken on this farm in Content,
resulting in the destruction of the entire plot.
Plate 4.3. Makeshift scarecrow on farmland near the community of Mount Pleasant, Portland.
13
Damage to Woodland Areas
Although damages to woodland areas were not directly investigated, there were some obvious
signs of antler damage to trees within the area occupied (Plate 4.4). The damages trees were
observed in highly degraded woodlands interspersed with agricultural fields. There were no
reports of deer presence within the forest reserve of the Blue and John Crow Mountains
National Park
Plate 4.4. Bark fraying of a young tree near Mount Pleasant, caused by deer thrashing the antlers
up and down against the stem during territorial displays.
Deer hunting
Some farmers set rope snares for the animals, but deer are very trap wary, and have seldom been
caught using this method. Deer hunting with the help of hunters from the Kingston area is
becoming increasingly popular, and deer are tracked and shot on a weekly basis with the help of
tracking dogs. Only one community member (a farmer) is involved in leading deer hunting
expeditions, and he reports seeing approximately 300 deer killed over the last 3-4 years.
14
Income from deer
Economic gain from deer presence has been negligible. Only one community member is actively
involved in leading deer hunting expeditions, from which he receives a small financial gain for
his services as a guide. This only offsets the losses he receives through crop damage. Hunters
return home with their catch, and either sell it or consume it. Local catch is rare, and only used
for subsistence. One local touring organization conducts the occasional deer-photographing
outing, charging $1500 per person.
Deer Abundance
Five dung piles were recorded along 20 transects (Plate 4.5). Density calculations were done for
the core areas totaling approximately 7.6 km2, within the total 19 km2 area occupied (Figure 4.4).
Plate 4.5. O. virginianus dung pile in an area dominated by bamboo near the community of
Content
Using DISTANCE (Buckland et al., 1993), a dung density (T) of 23914.86/km2 was estimated,
based on the number and distances of the dung piles from the transects. Deer density (D) was
estimated at 23.90 deer/km2, and deer abundance (N) was estimated at 182.
15
DISCUSSION
The distribution of O. virginianus in Portland was smaller than anticipated. Given that the animal
has been established in the island for approximately 15-20 years, its dispersal has been fairly
minimal, and its range has been confined to a relatively small area. Marchinton and Hirth (1984)
found that movements and home range in deer are variable, and are influenced by age, sex,
density, social interactions, latitude, season, and habitat characteristics. Therefore any number of
factors could be influencing the distribution of O. virginianus in Portland.
O. virginianus’ distribution in Portland is characterized by relatively low altitudinal areas (50m-
300m) permeated by streams, and set apart from towns and communities. Areas occupied
consist of degraded forest in close proximity to the animal’s preferred agricultural crops.
The area occupied by O. virginianus appears to be constrained by a number of factors. In the
southern region of the range, they are probably constrained by crop type, as coffee, banana and
plantain (which are not the animals’ preferred crop types) are the main crops grown. To the east
of their range, the species is probably inhibited by more densely populated towns and
communities like Mount Pleasant and St. Margaret’s Bay. These towns also probably have a
greater occurrence of dogs, the presence of which will work to deter deer. In those communities
occupied by O. virginianus, farmers rarely keep dogs, for fear that they would prey on goats and
other reared animals. The Swift River, and a change in crop type (from pumpkin and carrots, to
plantain, banana and coffee) probably restricts the animals to the west of their range.
It appears that deer have not managed to establish themselves in the Blue and John Crow
Mountain forests. These mature forests are probably unsuitable habitat as they contain little
undergrowth which deer need for cover and browsing.
The density of O. virginianus (23.9 deer/km2) in the core areas occupied, was found to be
relatively high. Aulak and Babinska-Werka (1990) note that in small wooded areas surrounded
by agricultural fields, the abundance of roe deer is 3 times as high as the density levels for
woodlands in Poland. The animals were found to temporarily leave the shelter of the woodland,
move into nearby fields, and use the vegetation as an additional food source. In their study of a
small forest area (200 ha) in Poland, surrounded by agrocoenoses, they found a high roe deer
density of 45-62 deer/km2, and not surprisingly, the agrocoenoses bordering the forest were
intensively used by deer. Areas with numerous small agricultural plots in Quercus-Carya forests
16
in North Carolina were found to support high densities of 80 deer/km2 (Torgenson and Porath,
1984).
My O. virginianus density estimate is limited by a number of factors. Ideally, defecation rates and
dung decay rates should have been estimated from independent studies done on the population
under consideration. These parameters are highly variable and habitat specific, but such
investigations were not practical given the scope of this study. In addition, the relatively small
number of dung piles found (5) resulted in large confidence limits. Nevertheless, the abundance
estimate of 182 deer in the core areas occupied, with an upper 95% confidence limit of 373 deer
appears to be reasonable, based on (1) the relatively small, yet high quality habitat occupied, and
(2) farmers’ estimate of 500 – 1000 deer. Farmers’ estimates are however, based on sightings and
crop damage, but the same group of deer could be returning to raid crops in each instance, and
as such, a population size of 500-1000 individuals is likely to be an overestimation. Using the
population growth rate of white-tails on the George Reserve (McCullough, 1982 and 1983), with
a founding population of 6 individuals (Shaw, pers. comm.) growing over a period of 15 years, the
result is a potential population size of 12, 416 individuals in Portland. The population size in
Portland would probably approach this value if it was uninhibited, and this is an indication that
there are inhibiting factors to deer population growth in Portland, one of which might be
hunting.
A more accurate deer population size estimate could have been attained if a larger sample size
(number of transects), with longer transects was taken, and if the area occupied was divided into
strata (woodland versus cropland).
Odocoileus virginianus and the Portland farmer
Portland is primarily an agricultural parish, and the vast majority of farmers operate relatively
small farms (<0.5 km2). The small farm sector is the country’s largest source of employment,
supporting an estimated 150,000 rural families (NEPA, 2003). It is these small farms in Portland
that receive the highest damage levels. Smaller farms have a larger perimeter to area ratio, which
leaves them more susceptible to damage from deer entering the edges of plots, from adjacent
woodlands. Smaller farms also have fewer crops, and so the effect of deer raiding can be
catastrophic.
17
Farmers reported that deer raiding had intensified over the past 5-6 years, suggesting that the
deer population has been increasing. On the other hand, some farmers reported that deer
raiding had lessened in the past 1-2 years, perhaps reflecting reduced density attributable to
hunting mortality.
In general, farmers have apparently met with little success in their measures to deter crop raiding
by deer. After a few weeks, the animals usually become accustomed to the scarecrows and other
frightening devices employed by farmers. Further, none of the farmers interviewed had switched
crop types to those less preferred by O. virginianus; they explained that this would not be feasible,
given the local market conditions.
Some farmers experienced losses in certain crop types, while others did not. This was probably
due to the location of the crops within the field, or the location of the field itself, as fields
located closer to woodland areas are more likely to be raided than are fields further away from
wooded areas (Aulak & Babinska-Werka, 1990).
CONCLUSION
Odocoileus virginianus in Portland is a serious agricultural pest, causing thousands of dollars in
damages to small farms. Given their present distribution, the animals seem to pose more of a
threat to small scale agriculture than to forested areas. Their presence may, however, have
implications for forest restoration in edge habitats.
Future numbers and geographical expansion of O. virginianus are strongly dependent on land use
patterns and hunting regimes. As is the case in lowland Britain (Putman and Moore, 1998),
farmed woodlands create refuges for deer, and serve both to increase densities in those areas
already occupied, and to provide migration corridors to new areas. If such migration corridors
containing the right crops continue to be made in The Blue and John Crow Mountains National
Park, it will only be a matter of time before O. virginianus invades this unique and vulnerable
ecosystem.
18
To better assess the status, and impending threat of O. virginianus to the Blue and John Crow
Mountains National Park, additional research, survey work and monitoring is clearly warranted,
in particular, along the northern foot hills of the Park.
RECOMMENDATIONS
1. O. virginianus is an alien invasive species, and the population in Portland should be
eradicated or controlled in an effort to safeguard the native biota, and to spare
agricultural losses. Since this is largely the view of community members, control efforts
are not likely to be met by opposition, as is often the case with introduced animal control
programmes. The most suitable method of control would probably be to have hunters
or members of the Jamaica Defense Force come into the area at prescribed times (set
during community consultations) to shoot deer. This could be regarded as a community
service, and the meat could be divided up among community members. In the
meanwhile, farmers should be compensated in some way for deer damage, to ensure that
immediate losses do not result in unemployment and social disruption.
2. Farm owners should be given technical support to help prevent deer raiding. One
potential method of deterring deer on farms in the Portland area is to keep dogs around
crop beds, although such an approach would not come without potential negative
consequences (example, adding to the feral dog problem and risking predation of reared
animals).
3. There is currently no legislation that addresses the issue of bringing alien animals and
plants into Jamaica, nor is there a coherent, national strategy aimed at ameliorating the
deleterious impacts of introductions that have already occurred. More stringent laws
should be established that prevent the importation of any non-native species except
under special circumstances identified by the relevant authorities. An alien watchdog
group should be established that would be contacted on the first sign of a newly
introduced species, and the government and other relevant organizations should mobilize
to control or eradicate alien invasives wherever they occur.
19
REFERENCES
Aulak, W. and J. Babinska-Werka. 1990. Acta Theriologica. Use of agricultural habitats by roe
deer inhabiting a small forest area. 35: 121-127.
Barnes, R.F.W. 1993. Indirect methods for counting elephants in forests. Pachyderm 16:24-30.
Buckland, S.T., D.R. Anderson, K.P. Burnham, and J.L. Laake. 1993. Distance Sampling:
Estimating Abundance of Biological Populations. Chapman and Hall, London. 446pp.
Conover, M. R. 1995. What is the urban deer problem and where did it come from? Pages 11-18
in J. B. McAninch, editor. Urban deer: A manageable resource? Proceedings of the 1993
Symposium of the North Central Section, The Wildlife Society., 12-14 December 1993,
St. Louis, Missouri, USA.
Coomes, D. A., R. B. Allen, D. M. Forsyth and W. G. Lee. 2002. Factors Preventing the
Recovery of New Zealand Forests Following Control of Invasive Deer. Conservation
Biology 17(2):450-459.
deCalasta, D.S. 1994. Effect of white-tailed deer on songbirds within managed forests of
Pennsylvania. J. Wildl. Manage. 58:711-718.
DeNicola, Anthony J., Kurt C. VerCauteren, Paul D. Curtis and Scott E. Hygnstrom. 2000.
Managing White-Tailed Deer in Suburban Environments: A Technical Guide. Cornell
Cooperative Extension, the Wildlife Society-Wildlife Damage Management Working
Group, and the Northeast Wildlife Damage Research and Outreach Cooperative. 52pp.
Doney, J. and J.J. Packer. 1998. The impact of deer on agriculture: interim results of a
questionnaire and subsequent validation. In: Population ecology, management and welfare of
deer. Eds. Goldspink, C.R., King, S. & Putman, R.J. Manchester Metropolitan University,
Manchester.
Forestry Department, Ministry of Agriculture. 1998. Land Use map of Portland.
Fuller, R.J. and R.M.A. Gill. 2001. Ecological Impacts of increasing numbers of deer in British
woodland. Forestry 74(3):193-199.
Gladfelter. 1984. White-tailed deer populations and habitats of the Midwest agricultural regions.
pp 427-440, in White-tailed deer: ecology and management (L.K. Halls, ed.). Stackpole
Books, Harrisburg, Pensylvania, 870pp.
Guthrie, R.D. 1971. The evolutionary significance of the cervid labial spot. Journal of Mammology.
52:209-212.
20
Halls, H. K., ed. 1984. White-Tailed Deer: Ecology and Management. Harrisburg, Pa.: Stackpole
Books.
Harmer, R., G. Kerr and R. Boswell. 1997. Characteristics of lowland broadleaved woodland
being restocked by natural regeneration. Forestry 70:199-201.
Hesselton, W.T. and R.M. Hesselton. 1982. White-tailed deer. Pp 878-901, in Wild mammals of
North America (J. A. Chapman and G.A. Feldhamer, eds.). The Johns Hopkins
University Press, Baltimore.1,147 pp.
Horsely, S.B. 1977. Allelopathic inhibition of black cherry by fern, grass, goldenrod, and aster.
Canadian Journal of Forestry Research 7:205-216.
IABIN. 2003. Invasive Species Information Network Project - Jamaica (I3N-JA) Catalogues.
http://www.jamaicachm.org.jm/Catalogue/PlantsorAnimals.htm
Kay, Q. 1993. Genetic differences between populations of rare plants. BSBI News, 64: 54-56.
Manchester, S. J. and J. M. Bullock. 2000. The impacts of non-invasive species on UK
biodiversity and the effectiveness of control. Journal of Applied Ecology 37:845-864.
Marchinton and Hirth. 1984. Behaviour in White-tailed deer: ecology and management (L. K. Halls,
ed.). Stackpole Books, Harrisburg, Pennslyvania, 870pp.
Marshall, F. 1970. Deer and the Farmer. Deer. 2:514-516.
Marquis, David A. and Brenneman, Ronnie. 1981. The impact of deer on forest vegetation in
Pennsylvania. Gen. Tech. Rep. NE-65. Broomall, PA: U.S. Department of Agriculture,
Forest Service, Northeastern Forest Experimental Station 7pp.
Mayle, Brenda A. and A.J. Peace. 1998. Recent progress in determining deer population size:
Factors influencing faecal pellet group decay. Proceedings of the 4th International Deer
Biology Congress. pp 57-61.
McCullough, D. R. 1979. The George reserve deer herd, population ecology of a k-selected
species. The University of Michigan Press, Ann Arbor. 271 pp.
McCullough, D. 1982. Population Growth Rate of the George Reserve Deer Herd. J. Wildl.
Manage.46(4):1079-1084.
McCullough, D. 1983. Rate of increase of white-tailed deer on the George Reserve: A Response.
J. Wildl. Manage.47(4):1248-1250.
McClanahan, T.R. 1986. Quick population survey method using faecal droppings and a steady
state assumption. African Journal of Ecology 24:37-39.
Mech. 1984. Predators and predation of the white-tailed deer. pp 189-200 in White-tailed deer:
ecology and management (L.K. Halls, ed.). Stackpole Books, Harrison, Pensylania, 870pp
21
Moore. 1999. Factors influencing browsing by fallow deer Dama dama in young broad leaved
plantations. Biological Conservation 87(2) pp255-260.
National Environment and Planning Agency (NEPA), Ministry of Land and the Environment.
2003. Towards a National Strategy and Action Plan on Biological Diversity in
Jamaica.
Parkes, J.P., G. Nugent and B. Warburton. 1996. Commercial Exploitation as a pest control
tool for introduced mammals in New Zealand. Wildl. Biol. 2:171-177.
Putman, R. J. and N. P. Moore. 1998. Impact of deer in lowland Britain on
Agriculture, forestry and conservation habitats. Mammal Rev.28:141-
164.
Relva, M.A. and T.T. Veblen. 1998. Impacts of introduced large herbivores on Austrocedrus
chilensis forests in northern Patagonia, Argentina. For. Ecol. Manage.108 (1-2):27-40.
Rogers, L.L. 1987. Seasonal changes in defecation rates of free-ranging white-tailed deer. J.
Wildl. Manage. 51(2):328-331.
Schmitz, Don C. and Daniel Simberloff. 1997. Biological Invasions: A Growing Threat. Issues
in Science and Technology.
Scott, D. and S.C.F. Palmer. 2000. Damage by Deer to Agriculture and Forestry. Report to
Deer Commission for Scotland. Institute of Terrestrial Ecology, Banchory Research
Station.
Simberloff, D. 2000. Global climate change and introduced species in United States forests. Sci.
Total Environ. 262 (3):253-261.
Simberloff, D. 1995. Why do Introduced Species Appear to Devastate Islands More than
Mainland Areas? Pacific Science 49(10): 87-97.
Smith, W.P. 1987. Dispersion and habitat use by sympatric Columbian white-tailed deer and
Columbian black-tailed deer. Journal of Mammology. 68: 337-347.
Smith, W.P. 1991. Mammalian Species: Odocoileus virginianus 388:1-13
Taylor, W.P. 1956. The Deer of North America. The Stackpole Company, Harrisburg,
Pennsylvania, 668pp.
Thomas, L., J.L. Laake, S. Strindberg, F.F.C. Marques, S.T. Buckland, D.L. Borchers, D.R.
Anderson, K.P. Burnham, S.L. Hedley, and J.H. Pollard. 2002. “Distance 4.0. Release
1”. Research Unit for Wildlife Population Assessment, University of St. Andrews, UK.
http://www.ruwpa.st-and.ac.uk/distance/
22
Torgenson and Porath. 1984. White-tailed deer populations and habitats of the Midwest
oak/hickory forests. Pp. 411-426, in White-tailed deer: ecology and management (L.K. Halls,
ed.). Stackpole Books, Harrisburg, Pensylvania, 870pp.
Wardle, D.A., Barker, G.M., Yeates, G.W., Bonner, K.I. Ghani, A. 2001. Introduced browsing
mammals in New Zealand natural forests: Aboveground and belowground
consequences. Ecol. Monogr. 71:587-614.
Wigley, T.B., and M.K.Johnson. 1981. Disappearance rates for deer pellets in the southeast.
Journal of Wildlife Management 45: 251-253
Wilson, E. O. (1992).
Wilson, E. O. (1992). The Diversity of Life. W.W. Norton & Co., New York.