Crop Damages by Wild Animals - Global View
Crop Damages by Wild Animals - Global ViewG.M. Wani, Ph.D ; D.V.M (Germany)Wild animal-human conflicts have started since beginning of human era from Adam and Eve. This conflict of wilderness made man to hide in caves and he was called as “Cave man”. Slowly, with his advancement it is he who invented Axe and other weapon in stone and iron ages to frighten the wild animals, initially. Later on he hunted them to save himself. This feeling of uncertainty and fear of wild animals and wilderness reduced with the invention of fire. He made sharp weapons of bones and iron. These initial weapons were the beginning of this conflict, Animal human conflict.Wild animal-human conflicts have started since beginning of human
era from Adam and Eve. This conflict of wilderness made man to hide in
caves and he was called as “Cave man”. Slowly, with his advancement it
is he who invented Axe and other weapon in stone and iron ages to
frighten the wild animals, initially. Later on he hunted them to save
himself. This feeling of uncertainty and fear of wild animals and
wilderness reduced with the invention of fire. He made sharp weapons of
bones and iron. These initial weapons were the beginning of this
conflict, Animal human conflict.
Thirty thousand years ago, the human population rose to 6 million.
They were still hunters. With the invention of fire, he set fire a vast
majority of sanctuaries, which scared wild life and they migrated from
his neighborhood. Many forests, hills and difficult terrains were still
beyond the reach of man three thousand years before, although human
population has increased to 60 million. Man has already started
primitive agriculture. He had made his terrains and wild life scared by
him left his close habitats and searched for fresh abodes. Man by now
had lust for fur, horns, ornaments and other forest resources. He
invented many means to frighten whole wild life. He became a “Danger “not only for wild animals but for his own species, environment and eco-biodiversity.
Three hundred years ago he industrialized crop production and
produced enough food, for nearly 600 million people. This continued and
from 30 year now he is feeding 6000 million people. Today we have a
global food security for 7.5 billion. Human food security gains
resulted in reduction of all other wild species, thus, the origin of
wild- life- human conflict is the lust of man for more food, more
luxury or sometimes fun for hunting or fur. This reduced wild life
reserves and now a open conflict came into existence.
Many man-wild life conflicts have been reported from Gir forests of Gujarat, Rajaji National Park in UP
and many other states where forest lands became cultivable lands.
Elephants, wild boars, monkeys, squirrels, deer , birds like crows,
parakeets, wild dogs, jackals, gaur, sambur, langure, fowls, pea cocks,
neilgai, Hippos, biats, blackbirds, rodents, wild pigs, feral species,
primates, beetles, foxes, pigeons, feral hogs and a variety of other
species damage crops. The carnivores even attack human too. These
attacks are for search of food or their loss of habitat. Many such
accidents came to be known in Jammu and Kashmir. The bear leopod and
other wild animals are reducing in number. Their habitats used by human.
The human causalities are due to carnivorous species, but herbivores
inflict economic and human losses too. The crop damages by wild life
has been the new threat to agricultural productivity throughout the
world. This also concerns us in Asia and India. This review is aimed to
find out:
1. Extent of damage to crops.
2. Nature of crop damage
3. Ways and means to prevent these losses.
4. A strategic planning to drive a line between wildlife conservation and farm economics especially in India.
Executive Abstracts and Strategic elementaries: [EASE]
1. Importance
Species causing crop damages ranges from
elephant’s wild birds, monkeys, squirrels, deer, parakeet, wild dogs,
foxes, deer and many others like Neilgai. On an average this damage to
crops by wild animals amounts to U$ 961 per hectare. It is much more
than an Indian Farmer earns from a hacter annually. Therefore, by these
estimates, the damages are spectacular and economically important.
2. Human Elephant conflicts (HEC):
i) Economic Losses:
Among elephants crop raiding is common. The crops
near their home ranges are damaged more. Elephants damaging crops had
twice big ranges than those who did not damage the crops. Thus, more
proximity of the crops near their ranges are prone to crops damages.
Train accidents instigate elephants more to crop or human damages.
Indonesia saw more frequent raids of elephants on crops. Human elephant
conflict (HEC) is frequent and poses serious challenges in Africa. Both
male groups and family group attacks have been observed. HEC losses in
West Bengal were worth 3.2 croses of Rupees. This damage occurred in
3368sq kms.radius. The numerical number of elephants was 62 only. Assam
observes damages to the woodcutters by elephants Asian wild Elephants
raid and damage crops in herds of 10-13 individuals or big herds
comprising 50-74 elephants. In Darjeeling district alone over an area
of 200 kms. East to west, in last two decades 277 houses were
demolished by elephants, killing 66 people in 5 districts. As a result
of this conflict 23 elephants lost their lives. In 2001, economic loss
of the order of US fifty thousand dollars was estimated to be inflicted
by elephants. This scenario necessitates comprehensive measures to be
taken to lessen these damage. The review of the measures, around the
world suggest following few studies to be undertaken and resultant
measures to be applied to lessen these damages.
ii) Mitigation of losses:
Methods developed and used to mitigate crop damages by
elephants consisted of frightening of animals by drum beating,
firegracks or even air gun fires. Guarding the crops by fences or even
using electric fencing or raising poles and wiring may be effective.
Chemical based deterrents, and electric fencing have been found to
reduce crop damages. High voltage electric fencing using energizers in
west have prevented wild animals damaging crop but this preposition may
not be applicable in areas where even habitations do not have access to
electricity. However, this method may act as a temporary boundary
separating wild and domestic habitats. This could prevent intrusions
from sly vatic to domestic foci. Guarding fields, digging trenches,
modifying cropping patterns have a possibility of reducing man elephant
conflicts or Human elephant conflicts. A 30% open space between two
habitats may help to avoid HEC. This means a distance to be maintained
between cropping fields and elephant habitates. A proper investigation
on these lines is needed. A grid based geographical information system
(GIS) with a 25Km2 resolution may help to have cost effective data
source to analyze these situations. There is urgent need of identifying
spatial predictors of HEC. On the basis of this study one can suggest
or plan mitigation strategies, early warnings of attacks, use of
barriers and deterrents. The utility of the methods could be assessed
for land use and livelihood strategies to limit HEC.
3. Dear-Nilgai Damages.
A survey of 2500 farms in UK revealed that 69% (n=192)
cereal crops were damaged by deer. This damage costed £500 per annum
per farm. Damages varied with deer density. In USA too deer damages
comprised of crop loss, landscape damages, car accidents and property
damages. Nilgai damages alongwith deer damages are common in India too.
Tree cover of Acacia in the area is generally used as shelter by
Nilgai. We have encountered huge crop damage in Mathura (CIRG) and
nearby area by Nilgai visits. Grazing and browsing of Nilgai inflict
losses on farms. This is regarded as a mammalian crop threat by the
farmers. This behaviour of their inflict ozone injury to the young
sapling, so precious for the growth of trees in Indian semi-arid farms.
Corn damages by deer in USA amounts to 6.6.% per hectare.
In an area where a farmer owned 125 hectare on an average 55 hectares
were used to sow corn. There is a 6.6% loss of the product which is a
huge economic loss. Similar damages by deer in Ontario, Canada,
Portugal, Japan, South America and other parts of the world have been
reviewed. In Virginia too a study involving 1506 agricultural producer
farmers revealed 58% of them experiencing deer damages. Ways and means
to prevent such attacks on crops have been reviewed. Most of the
possible measures to be adopted are similar to these described for
elephants (HEC).
4. Other Mammal and bird damages
Monkey damages maize, sweet potato and other crops. It is
suggested to reduce or change cropping pattern or alternating with
non-agricultural activities near location of monkey habitats. Various
methods are reviewed. Bat damage, Hygo crop damages in Japan, Grape
wine damages by bats in Andra Pradesh, India have been studied. Crop
economic loss assessment has been reviewed in these pages. Clover
rather than grass can reduce wild mammal damages. Alley cropping of
black walnuts helped to save soyabean and maize crop damages. Pesticide
damages wildlife and minimize their attacks, enclosures and other
electric fencing help to avoid such damage. Can one use harmful means
to save crops, need a suitable strategy to preserve ecology and
biodiversity. Both crops and wild animals need security and
conservation. A management strategy is needed to safeguard human and
wildlife equally. A policy framework is envisaged.
Blackbird crop damage in USA amounts to 5-8 million
dollars. A considerable sum of crores of rupees have been estimated to
be damages in the form of crop, human and property losses by wild
animals, birds and other rodents in India. Many measures to reduce
these losses are needed and have been reviewed.
Review
1. Wild animals damaging crops
To elephants wild boar, porcupine, rheus macaque (Macaca mulatta),
hoary-bellied squirrel, barking deer (Muntiacus muntjak), red-breasted
parakeet (Psittacula alexandri), and wild dog are wild animals damaging
crops.
Methods developed and being used to mitigate man-wildlife conflict
include, frightening the animals; guarding the crops; and using some
sort of scarecrow and traps (Miah et al 2001).
Accurate estimation of crop damage by wildlife (raccoons,
white-tailed deer, and coyotes) often requires labour-intensive
sampling procedure. Variable area transect (VAT) sampling has been
identified as a potential labour-saving alternative to quadrat sampling
( Engerman et al 2002).
2. Wild life Human conflicts
Agricultural landowners suffer in the form of damage to crops,
livestock, and other property. Some wildlife agencies maintained
abatement and compensation programmes. A model of deer-inflicted crop
damage used to facilitate agency decisions regarding deer densities and
distribution, abatement use, and to forecast compensation. The model is
applied to field-level compensation claims in Wisconsin, USA. The
results are consistent with theory, ( Yoder J, 2002).
3. Crop Economic loss due to wild life
People’s perceptions were discerned through participatory
discussions covering 419 households distributed in 10 villages in the
buffer zone. Traditional uncodified rights of local people were
substantially reduced through policy interventions set in since 1860s.
Local people as well as tourists have been excluded from the core zone
covering an area of 625 km2 since 1982. Deterioration of rural economy
due to damage to crop and livestock by wildlife and, termination of
opportunities of income from wild medicinal plant resources and tourism
in the core zone were the key negative impacts of conservation policy
felt by more than 90% of respondents. Mean annual economic loss per
household was estimated as Rs.1285, Rs. 1195 and Rs.156 due to damage
caused by wildlife to food crops, fruit trees and beehives,
respectively, Rs. 1587 due to ban on collection of wild medicinal
plants for marketing and Rs.7904 due to ban on tourism in the core
zone. The Reserve authority granted compensation for livestock killed
by wildlife but it was hardly 5% of the market value of killed
livestock as assessed by the people. People did not appreciate much the
present benefits from the reserve management in the form of wages for
carrying out afforestation work, partial compensation for livestock
depredation and availability of solar power devices, wool, and spinning
devices. Approximately 95% respondents identified empowerment of local
people in respect of realizing income from timber from dead/diseased
trees in community forests, income from medicinal plants in buffer zone
and opening of the core zone for tourism as potential development
options. Improvement in rural economy, the prime concern of local
people, has not received as much attention as legal enforcement of
protection by the reserve management. There is a need for developing
policies and management actions that serve the economic interests of
local people together with enhancement of environment conservation goal
(Maikhuri et al 2001).
4. Crop selection:
Damage was less (34%) in experimental carrot as multiple crop than
carrots as only crop planted (62% damage). Staggered plantings of
canola, which continuously produced flowers, was the most effective
lure crop of the green manure crops we tested. Carrot producers should
use electric fences or 2.4-m woven wire fences, perhaps combined with
staggered canola plantings, to reduce carrot depredations ( Schwab et al 2001).
The colver, rather than fertilized grass, is more
effective cover crop on AFAs, against damage by migratory geese. The
sward should be managed to encourage clover growth, which would
probably involve frequent cutting but no fertilizer. Further research
is needed on clover replenishment rate over the winter season and
possible benefits of clover leys to other wild life (McKay et al 2001).
Alley cropping of black walnuts and percent with maize and soyabean
rotations may avoid will animal damages. Tree –crop ratio of 1:10 may
help( Godsey, 2000).
5. Elephan- human conflicts:
Conflicts between elephants (Elephas maximus) and human occur in
Rajaji National Park (RNP), Uttar Pradesh, one of eleven reserves
designated in India, to conserve Asian elephants. Elephant-human. The
conflicts in RNP from 1996 to 1999 were studied, and all human and
elephant deaths or injuries caused by conflict were recorded. The
impact of human colonies on elephant movement was studied in 18
villages along 17 km of the sourthern boundary of the study site and 4
village in the Chilla-Motichur corridor. Three male and four female
elephants were radio tracked for 1-2 years. Primary conflicts included
crop raiding, competition between humans and elephants for vegetation,
and elephant mortality due to train accidents. Adult males that raided
crops had home ranges twice as large as adult males that did not raid
crops. Elephants only damaged crop of fields that occurred within their
home ranges. Field trails of chemical based deterrents and electric
fencing should be tried to reduce crop damage. Train speeds need to be
reduced to prevent accidental elephant mortality (Williams et al 2001).
Wild Elephant damages:
A rapid village and field assessments, data survey showed.
Elephants raided crops at a rate of 0.53 elephants per day in
Indonesia. The frequency of crop raiding was related to vegetation type
along the park border, the size and presence of rivers, and the
distance to the park’s Elephant Training Centre (ETC), which houses
about 150 captive elephants. Wild elephants damaged at least 450000 m2
of maize, rice, cassava, beans and other annual crops, and close to 900
coconut, banana and other perennial trees in the area surveyed.
Elephants killed or injured 24 .Villagers try to reduce elephant damage
by guarding fields, digging trenches between the park and their fields,
and modifying their cropping patterns. Elephants-human conflict
decreases the probability of support from local people for conservation
efforts. The approaches are suggested consist of elephant trenches,
electric fences, external support to affected villages, and
compensation to villagers for any damage caused (Nyhus et al 2000).
This study explores land use conflict in south east
Kajiado District, Kenya. The results of household surveys conducted
with farmers and herders in 1977 and 1996 to examine changes in land
management strategies are compared. The conflict reflects ongoing
competition over access to scarce land and water resources between
herding, farming and wildlife are the reason of damage of crops. This
man-animal conflict needs understanding the conditions that have
created the present conflicts (Compbell et al 2000).
It is, therefore, suggested that 30% open space be used as a basic
division for stratifying thickets into low –use and high-use categories
for deer density estimation. The proportions of each type could be
derived from grid-square measurements of aerial photographs (Latham J 2000).
Human elephant conflict
Human-elephant conflict (HEC) in Africa occurs wherever
these two species coincide, and poses serious challenges to wild life
managers, local communities and elephants alike. Mitigation requires a
details understanding of underlying patterns and processes. Although
temporal patterns of HEC are relatively predictable, spatial variation
has shown few universal trends, making it difficult to predict where
conflict will take place. Crop raiding was further subdivided into
incidents involving only male elephants or family groups. A relatively
fine-resolution, systematic, grid –based method was used to assign the
locations of conflict incidents, and spatial relations with underlying
variables were explored using correlation analysis and logistic
regression. Crop raiding was clustered into distinct conflict zones.
Both occurrence and intensity could be predicted on the basis of the
area under cultivation and, for male elephant groups, proximity to
major settlement. Conversely, incidents human injury and death were
less predictable but were correlated with proximity to roads. A
grid-based geographical information system (GIS) with a 25km2
resolution utilizing cost-effective data source, combined with simple
statistical tools, was capable of identifying spatial predictors of
HEC, At finer resolutions spatial autocorrelation compromised the
analyses. Synthesis and application. These results suggest that spatial
correlates of HEC can be identified, regardless of the sex of the
elephants involved. Moreover, the method described here is fully
transferable to other sites for comparative analysis of HEC. Using
these results to map vulnerability will enable the development and
deployment of appropriate conflict mitigation strategies, such as
guarding, early warning systems, barriers and deterrents. The utility
of such methods and their strategic deployment should be assessed
alongside alternative land-use and livelihood strategies that limit
cultivation within the elephant range (Sitati et al 2003).
Human elephant conflicts (HEC) in west Bengal was an
economic loss worth 3.2 crores. This much damage occurred in 3368 sq km
radius inhibiting 62 elephants (Singh et al 2002)
6. Kerala Survey
Crop damage by wild animals in Kerala, India, was studied from 1993
to 1996. Data were collected from the offices of the Kerala Forest
Department, field survey and from the intensive study area at Marayur,
Idukki District. Forty-five species of crops were destroyed by wild
animals in Kerala, the species commonly destroyed by wild animals were
paddy, coconut plam , plantains , cassava , arecanut, coffee, oil plam
, pepper , jack tree, mulberry and manago. The main animals involved in
crop damage were elephant (Elephas maximus), gaur (Bos gaurus),sambar
(Cervus unicolor), wild boar (Sus scrofa), bonnet macaque (Macaca
radiate), common langur (Presbytis entellus), blacknaped hare (Lepus
nigricollis) and pea fowl (Pavo cristatus). Among these, elephants and
wild board gave maximum damage . Of the total compensation claimed by
the farmers, only 8.2% was sanctioned by the Kerala Forest Department.
The highest crop damage (30%) was recorded from the forest ranges
coming under the Northern Circle: pinapple (47%) , sweet potato (47%),
tapioca (42%), alocasia (39%) , beans (25%) and plantains (23%)
recorded highest percentage of damage. In the intensive study area at
Marayur, 28 species of crops were damaged and highest damage was during
the summer months. At maximum damage was due to elephant (72%) followed
by gaur (62%) , sambar (17%) and wild boar (16%) . Tiger (Panthera
tigris), panther (leopard) (Panthera pardus) and wild dog (Conine
alpinus) were the main cattle lifters in the state. A total of 31
deaths and 64 injuries caused by wild animals were recorded from the
state during the period 1983 to 1993. Thirteen indigenous methods used
for controlling the crop damage had been identified. High voltage
electric fencing using energizer was effective for stopping elephants
and other herbivores from entering the agriculture fields. Crop damage
is found to be linked to the cropping pattern and location of the
agriculture fields. Short term and long-term measures needed to prevent
the crop damage are discussed (Jayson EA,1999).
7. Bird crop damages
Use of non-lethal method to avoid crop damages by bird have been
reported. Blueberry damages by cedar waxwings (Bombycilla cedrotun were
minimized. (Avery et al 2002).
8. Wild Bird damage
In the northern Great Plains of USA, conflicts between
red-winged black birds (Agelaius phoeniceus) and sunflower (Helianthus
annus) growers have intensified since the late 1960s due to the
expanded commercial production of sunflowers. We studied the potential
population effects of the removal of up to 2 million red-winged
blackbirds annually under a 5 year programme of baiting during spring
with DRC-1339 (3-choloro-4 methalalanine) treated rice. They also
examined whether lethal control, in combination with current levels of
breeding habitat management, would be cost effective in decreasing
depredation of sunflower crops during late summer. They evaluated the
cost benefit ration for 4 culling scenarios involving (1) variable
annual cullus, not exceeding 2 million birds, with and without density
compensation (i.e. ,a positive density-dependent response) on adult
survival and (2) culls of 2 million birds annually with and without
density compensation .We constructed a red –winged blackbird population
model represented as an age-based matrix and calibrated to stable
growth. We assumed a total population of 27 million birds on 1 April
(week 1), representing the red-winged blackbird breeding population
staging in eastern Southern Dakota and migrating into North
Dakota.Under each culling scenario, we reduced the stable red-winged
blackbird population (Equally for females and males) and project the
population through week 23 of the annual cycle (2 Sep). We then
evaluated the associated costs of the management relative to potential
sunflower crop losses, assuming $0.07 in damage per bird and 4% loss
to other factors. Variable annual culls, likely the more biologically
realistic model scenarios, yielded mean annual removals of 1 240 560
(SE=12 328) birds with density compensation and 1 231 620 (SE=28 811)
birds without density compensation,, with cost benefit ratios of 1:2.3
and 1:3.6, respectively. Annual intrinsic rates for the model
population over the 5 year period ranged from 1-4 to 4.8%. Considering
potential variability in the effectiveness of the cull and the
combination of direct and indirect costs,we contend that the realized
benefits to sunflower growers by lethal control of red-winged
blackbiards via spring baiting , in combination with current nonlethal
management efforts, would likely be negligible (Blackwell et al 2003).
The efficacy of hydrolyzed casein (HC) and retail products
that contain HC in reducing deer damage to trees and shrubs was
determined in a field experiments conducted in USA during 2004-05. The
results of the experiments indicate the suitability of HC as a deer
repellent. Technical grade HC completely eliminated browsing damage to
evergreen shrubs (Gaultheria shallon) and conifers (Thuja plicata).
Retail sources of HC were not as effective as the pure hydrolyzed
protein (Kimball et al 2005).
9. Blackbird damages
The economic impact of blackbirds can be severe to rice
producers in the United States. One approach to managing this damage is
the application of bird-deterrent chemical to the crop. Previous pilot
trials suggested that caffeine offered potential as a safe, economical
bird repellent. In this study, cage feeding trials with female red
–winged blackbirds and male brown headed cowbirds confirmed that a
treatment rate of 25000 ppm caffeine on rice seed reduced consumption
as much as 76% . Trials with mixed species blackbirds flocks in a
0.2-ha flight pen resulted in just 4% loss of caffine-treated rice
compared to 43% loss of untreated rice. . Field trials of a 10 000 ppm
caffeine treatment in Louisiana revealed > 90% of caffeine-treated
rice seed remained unconsumed on days 2 and 3 of the study whereas
blackbirds consumed > 80% of the untreated seed. As a rice seed
treatment to deter blackbirds, caffeine appears to be effective,
economical and environmentally safe, although additional aquatic
toxicity testing is desirable. Improvements in formulation will be
needed to make the compound practical for general agricultural spray
applications and to extend the adherence of caffeine to rice seeds in
field conditions ((Avery et al 2005).
10. Deer damage
A questionnaire was distributed to over 2500 farms to know damage
caused by lowland deer to crops, trees and vegetation. Results from the
questionnaire showed that 69% (n=1192) of responding farmers had deer
on their holdings and that Roe and Fallow were the most frequently seen
species. On those farms with deer present, cereals were the most
commonly damaged crop (44%), but only 15% of these farmers claimed that
the annual cost of damage to cereals exceeded £500 each year for the
whole farm. Validation assessments were based on two visits to assess
deer damage to the crop, with a deer species/density assessment during
the March assessment and an assessment of grain yield and quality
during the August assessment. Respondents were generally accurate in
the density and species of deer reported. The percentage of the farm
suffering damage attributable to deer was very variable, generally
being higher at the first assessment than the second. The figures
calculated for yield loss were generally low, Farmers were poor at
estimating the economic impact of deer damage when compared to
validation data, but a number of parameters may have changed in the two
years between the questionnaire distribution and validation, including
changes in deer density, crop rotations, and the marked drop in grain
prices, which may account for some of the inaccuracies. There were no
statistically significant relationships between deer damage assessments
and yield loss, either for individual species or both species combined.
The relationship between Roe deer damage at the harvest assessment and
Roe deer density was significant (Post et al, 2001).
Wildlife managers must consider the public’s preferences for
wildlife population levels when determining management policies. 849
farmers, hunters and the general public of Maryland. USA, were surveyed
in 1996 to determine their preferences for increasing, maintaining, or
decreasing deer population numbers. Using a random utility theoretic
framework, the factors that explain preferences such as residential
location, socioeconomic characteristics, landscape damage, agricultural
yield loss and vehicle accidents were analyzed. Results suggested that
the majority of people benefit from deer and want to keep deer
population at current levels. Other characteristics such as age,
income, education, and residential location have minor or no impact on
preferences. Property damage, crop loss, landscape damage, and car
accidents appear to be the biggest concerns ( Curtis et al 2001).
11. Sika deer population in Japan
Sika deer Cervus nippon population in eastern Hokkaido,
Japan, increased rapidly during 1990-1998 . This increase appeared to
have halted in 1999-2000, probably due to increased hunting and
nuisance control. The period of rapid increase was associated with a
disproportionately rapid increase in compensation paid for deer damage
to crops. We studied changes in diet during 1990-2000, as reflected by
stable isotope ratios of C and N in tooth collagen. We hypothesized
that isotope ratios would demonstrate dietary shifts related to
population levels and/or time, and that shifts in isotope ratios would
be consistent with increasing individual consumption of pasture
grasses at higher population levels, delta 13C isotope ratios of tooth
collagen in 3 year-old sika indicated a diet dominated by C3 plants
throughout the period, and that forage species other than pasture
grasses and dwarf bamboo Sasa nipponica ( the main crop and woodland
understory plants, respectively) were important elements. There was a
significant decline in the delta 13C isotope ratio during 1990-2000 in
both males and females, delta 15N values showed no trend with time for
males, but increased over time in females. Indices of population
(Sightings per Unit Effort, SPUE) were negatively correlated with
female delta 13C, and positively correlated with female delta 15N,
values indicating a shift in diet over the period , especially among
females. This shift may be related to population and/or offtake levels,
in particular the rapid increase in female offtake for nuisance
control and hunting during the period. The data are consistent with a
relative increase in pasture grass consumption per individual at higher
population levels, however, other explanations of the data are equally
plausible. Possible dietary changes, and other factors, influencing the
observed shift in isotope ratios are discussed. Although statistically
significant, the magnitude of dietary shifts nevertheless appeared
small, and did not provide evidence which would justify modifying the
current policy, of limiting crop damage through managed population
reduction to about 25% of peak levels( Halley et al 2006).
12. White-tailed deer damages
White-tailed deer (Odocoileus virginianus) may cause more
damage than any other species of wildlife. These damages include crop
loss, automobile and aviation collisions, disease transmission,
environmental degradation, and destruction of ornamental plantings.
One practical method of controlling deer damage is the use of
exclusionary fences. The relatively high cost of labor and materials
required to build effective fences has limited most applications to the
protection of orchards, vegetable farms, other high –value resources,
and mitigation of human health and safety risks. Improvements in fence
technology resulting in less expensive, yet effective fence have
expanded the use of fence to manage damage caused by deer. Fence
typically installed to manage white-tailed deer damage include wire or
plastic mesh, electrified high-tensile steel wire, and electrified
polytape or polyrope fence. They reviewed the scientific literature on
fencing to determine which fence designs would be the most effective
for excluding deer in a variety of situations (VerCauteren et al 2006).
The installation of fences to protect agricultural
products, natural resources, or other areas from deer (Odocoileus spp.)
can be expensive and potential benefits of fencing are difficult to
quantify. A rational method is needed to help evaluate whether fencing
can be cost effective and which fence designs will be optimal for
particular applications. They describe an interactive, dynamic
simulation model that conducts economic analyses and predicts economic
benefit associated with fences for crops relative to area and perimeter
of protected plot, value of crop, percentage of crop damaged by deer
annually prior to fencing, efficacy of fence, and costs of fence
materials and labor. Users of the model can easily adjust these
variables to fit their individual situations and needs. By running a
series of simulations, model users can answer questions related
directly to fence efficacy and cost-effectiveness (VerCauteren K et al 2006).
13. Corn damage by wild life
Corn damages in USA were estimated at 6.6 per hac due to
wild life. The white tailed deer was the wild animal responsible for
loss. The average hacters owned by farmers were 125 out of which 55
hectares were sown corn. (Tzilkowsi et al 2002).
14. Deer Damage
Deer (Odocoileus spp.) can cause substantial damage to
agricultural crops, resulting in economic losses for producers. They
developed a deer activated bio-acoustic frightening device to reduce
white-tailed deer (O, virginianus) damage in agricultural fields. The
device considered of an infrared detection system that activated an
audio component which broadcast recorded distress and alarm calls of
deer. They tested the device against unprotected controls in cornfields
during the silking-tasseling stage of growth in July 2001. The device
was not effective in reducing damage: track-count indices (F1,4=0.02),
corn yield (F1,9=1.27,P=0.289), and estimated damage levels
(F1,10=0.87, P=0.374) did not differ between experimental and control
fields. The size (F2,26=1,00,P=0.380), location (F2,25=0.39,P=0.684),
and percent overlap (F2,25=0.20,P=0.818) of use-areas of radiomarked
female deer did not differ between during and after treatment periods.
They concluded that the deer-activated bio-acoustic device was not
effective in protecting cornfields in this study; however, the device
may be more effective in small areas such as gardens or for high value
crops that do not grow tall enough to offer protective cover (Gilsdorf et al 2004).
White –tailed deer (Odocoileus virginianus) cause millions
of dollars of damage to agricultural crops annually . They tested the
effectiveness of propane exploders and Electronic Guards (Pocatello
Supply Depot, Pocatello, Id). For reducing deer damage in corn fields
during the silking-tasseling stage of growth. Track-count indices
(F2,7=0.70,P=0.532), corn yield (F2,6=0.14, P=0.873), and estimated
damage levels (F2, 12=1,45 P=0.272) did not differ between experimental
and control fields. The size (F2,11=0.08,P =0.924), Location
(F2,9=0.30, P=0.750), and percent overlap (F2,9=0.46, P=0.644) of use
–areas of radiomarked female deer in the vicinity of experimental
fields did not differ among before, during and after 18 day treatment
periods. In a related study, we placed propane exploders in cornfields
within use-areas of 12 radiomarked female deer. The deer did not react
appreciably to the devices; the size (F2, 17=0.08, P=0.921), location
(F2,22=1.37, P=0.275), and percent overlap (f2,10=0.47, P=0.636) of
deer use areas did not differ among before, during, and after 14 day
treatment periods. They conclude that propane exploders and Electronic
Guards have limited potential for reducing deer damage to corn at the
silking-tasseling stage (Glisdorf et al 2004l.
A welfare measure for wildlife damage to Ontario (Canada)
field crop producers during the 1998 was. The welfare measure presented
in this study provides a more accurate picture of losses from wildlife
damage to agricultural. Other damage estimates based on yield loss
overstate the damage since benefits from wildlife are netted out.
Results for the Ontario field crop producers indicate that the
magnitude of the difference between the value of the yield loss and the
welfare measure of damage is approximately 50%. This difference
indicates that most farmers were willing to tolerate the wildlife
damage they experienced (Heigh et al 2001).
15. Grapevine damages
In field trials in 1999-2000 in Gundla Pochampally, Andhra
Pradesh, India , the incidence of damage to green grapevines was
studied. Visits to the vines by bats begain around 45 minutes after
sunset and foraging continued until 1 hour before sunrise. Damage
occurred to ripe fruit only, and increased around harvesting time,
percentage damage ranged from 0 to 100% (Bhargavi et al, 2001).
16. Hippo damage
The introduction to the paper described the various
ecological effects known to result from grazing, movement along paths,
and wallowing by the common hippo. Hippopotamus amphibious. The study
reported was carried out at Kainji Lake National Park., Nigeria, during
the dry season periods {of 1991 and 1992} . The method adopted by
Agnew, A.D.Q. (East African Wildlife Journal (1966) 4, 38-46) was used
to assess hippo foraging footprints at three hippo pool sites. A total
of 32 footpaths were enumerated out of which 18 were located at Kaii
hippo pool site, while the frequency of utilization of paths was also
higher for this site relative to those in other area. The
upstream-downstream trend in hippo occupancy of dry season water pools
could expose the hippo to crop damage conflicts at the peripheral areas.
17. Hygo-Japan-mammal crop damages
Mammals inhabiting Hyogo consist of seven orders, 17
families and about 40 species. Except for Lagomorpha and Artiodactyla,
the remaining five orders among them include species which need some
protection and they total about 55% of all species excluding extinct,
introduced and feral species. Ecological information in Hyogo
prefecture has been accumulated in few protection-required species
there is no recent information of spatial distribution on Oriental
water-shrew, Japanese noctule-bat and Japanese dormouse; and little
information on Japanese shrew, Japanese horse-shoe bat, Japanese large
–footed bat. Schreiber’s bent-winged bat, Japanese tube-nosed bat,
common parti-colored bat, Japanese squirrel, Japanese small
flying-squirrel, Japanese giant flying-squirrel, smith’s vole harvest
mouse and Japanese badger. Damage and population managements is also
necessary in sika deer and Japanese wild boar, to reduce their
crop–damaging, and comprehensive management in Japanese black bear, an
endangered local population, to prevent human-bear fatal accident.
Habitat alteration due to human activities, however, has affected the
population sizes and spatial distribution of all these, mammals in
Hyogo. Habitat management has priority over damage. Fundamental and
applied scientific studies and understanding of ecology and wildlife
management science needs promotion by citizens (Mitani M 2000).
18. Monkey damage
Forty-seven property owners in Entebbe, Uganda were
questioned about vervet monkey activities on their property. The
objective was to investigate the interactions between humans and vervet
monkeys in an agricultural area adjacent to a forest zone. Other
studies have reported that farms located within 300 m of a forested
boundary probably incur the greatest risk of crop-raiding. Two other
factors that may influence susceptibility to vervet crop-raiding were
also examined: the types of crops grown and the types of direct
preventive measures used. The effect of these two factors on vervet
crop-raiding is not straight forward. However, the distance a property
is located from the forest edge is an important factor influencing
vervet crop raiding. Surveyed gardens 200 m from the forest edge
received significantly less crop –raiding than farms located 100 or
50m (P=0.040,Saj et al 2001).
19. Bait damage
The longevity of zinc phosphide (ZP) on whole wheat bait
was determined at the end of the “dry” and “wet” seasons, is Western
Australia.. While the total rainfall during the two trials was 74 mm
and 155mm, substantial loss of ZP was recorded only after significant
rainfall events. Irrespective of season, the loss of ZP from bait
applied in bait stations was minimal. The maximum recorded loss was 17%
and this occurred after 21 days’ exposure during the wet season where
the bait stations were placed in-crop. Nevertheless, regardless of the
application method, sufficient ZP always remained on the wheat bait.
Theoretically it was lethal to rats for at least 8-14 days (Twigg et al., 2001).
20.Venezuela experience:
In Venezuela, lethal control of wintering Dickcissels
(Spiza Americana) is considered a threat to the species survival. To
help farmers protect their rice and sorghum crops from by Dickcissels
and to minimize the killing of large numbers of these birds,
alternative non-lethal crop protection measures are needed. To that
end, the responses of captive Dickcissels to three bird-repellent
chemicals (anthraquinone,methyl anthranilate and methiocarb) applied to
rice seed were evaluated. In one-cup feeding trials, treatments of
methiocarb (0.05% g/g, applied as Mesurol 75% wettable powder) and
anthraquinone (0.5%, applied as Flight Control) reduced consumption of
rice by 70% relative to pretreatment consumption. Other anthraquinone
treatments (0.05,0.1%) and methyl authranilate (0.05%) were
inrffective. In two –cup trials, with untreated millet as the
alternative food, consumption of rice treated with 0.05 and 0.1%
anthraquinone was reduced by 90% relative to pretreatment levels.
Overall, Dickcissels responded to the repellents similarly to the
red-winged blackbird (Agelaius phoeniceus). Because Flight Control has
been used successfully to reduce blackbird use of rice fields in the
USA, the prospect is good for successful reduction of damage to
repening rice by Dickcissels in Venezuela, particularly if repellent
use is coupled with the establishment of alternative feeding sites ( Avery et al 2001). Deer selected carrots over all green manure crops.
21. Nilgai damages in India
Crop-damage by nilgai has been widely reported from
India. Are give Nilgai is for increasing in this region. Lack of
natural predators, deforestation overgrazing and the protection of
these animals from Hindu communities are reasons for their
overpopulation. Tree cover of Acacia are generally used by nilgai as a
day time shelter but not food, therefore it goes for crop-raiding in
the late evening and at night, jumping across 6-7 feet high stone wall,
barbed fencing and fences of dead or live thorny plant material and any
other fencing/barrier made to protect the crop-. Due to habit of both
grazing as well as browsing they devore every kind of farm species
(both rabi and kharif crops). It has been observed that eating less but
destroying more by trampling and causing damage are therefore regarded
as serious mammalian crop pest and farmers wants to get ride of this
unconventional pest. The farmers chase them away by just following them
by making loud sound by crackers or air gun fires, following through
tractors, empty tin or dried pumpkin filled with small stones and
connected with strings. Technically, carrots(enclosures), trenching or
power fencing are suggested to mitigate the crop damage. Secondly,
animals could be translocated to wildlife sanctuaries from the sites
they seen overcrowded or severe crop raiding problems (Goyal et al 2000).
22. Pesticides and wildlife
A range of monitoring activities has shown impacts of
anticholinesterase pesticides on UK wildlife, and continued risks are
evident from laboratory and field experiments, together with the scale
of use in the field. Along with other broad spectrum insecticides, many
organophosphates have adverse direct effects on non-target arthropods
in farmland, and so are likely to contribute towards indirect effects
of pesticides on farmland biodiversity. The anticholinesterase
insecticides have both lethal and sublethal effects on aquatic
wildlife, however the history of recent incidents of damage to river
ecology following the wider use of synthetic pyrethroid sheep dips,
illustrates the need to consider the implications of changes in the use
of alternative products when reviewing these insecticides ( Burn 2000).
The use of anthraguinone-based flight control and methyl
anthranilate-based non toxic avian foraging repellent we used to avoid
crop damage by sandhill cranes. Thought both repellents were effective
at deterring cranes from treated corn, neither has been tested on corn
under field conditions. (Blackwell et al 2001).
Oak seedlings were scientifically raised. Seedling
mortality and wild life browse damages were minimal when certain
herbicide mixture was used. Biologically and aesthetically, the
procedure was extremely successful (Ezell et al 1999).
Pre-commercially thinned (forests are less prone to moose damage (McLaren et al, 2000).
23. Pesticide use in conflicts
Pesticides can cause damage to man and beneficial
organism. Some sub-lethal effects of pesticides were studied in birds
with a view to identifying characteristic biochemical responses that
may be useful for the monitoring of exposure to sub-lethal levels in
the field. Pesticides were used; demeton-S-methyl, (DSM),chlorpyriphos,
chlorfenviphos, triazophos, pirimicarb, methiocarb and permethrin.
Blood was collected before dosing, and 2,6,24,48 and 72 hours after the
treatment from the brachial vein of birds. Enzyme, activities were
assayed in the plasma or serum samples obtained. The assays used were
GOT,MHD, GDH, SDH,GAMMA GT and ChE. The results showed an increase in
plasma and serum GOT and gamma-GT levels were found in all animals
treated with the previous pesticides. The level of ChE increased in
birds after treatment with permethrin. It was concluded that the
pesticides cause structural and functional changes in the liver and
also, the measurement of the previous parameter activities may be
useful for assessing exposure and sub-lethal effects of pesticides on
the wildlife (Dahamna et al 2004).
24. IPM and crop losses
The queensland sugar, industry has recently implemented a
comprehensive integrated pest management (IPM) system to minimize crop
losses from two antive rodent species, Rattus sordidus (canefield rat)
and Melomy burtoni (climbing rat). These species inflicted
approximately $25M of damage in a major outbreak in the 1999-2000
seasons. Both of these rodents are listed as common wildlife under the
schedules of the queensland nature Conservation (Wildlife) Regulation
1994. The IPM programme is based on understanding the ecology and
biology of each species. It incorporates a large-scale monitoring
programme aimed at providing early warning of imminent rodent build up
to avert major outbreaks. The industry has also developed a memorandum
of understanding with Queensland State Government, which delivers on
the industry’s pest management needs, while providing an improved
system of accountability for the taking of two of Queenslands native
wildlife species. The consensus reached between the cooperating parties
(The Bureau of sugar Experiment Stations, CANEGROWERS, regionally-based
Cane Productivity Services, and the outcomes can be negotiated between
rural industry and environmental interests (Hunt et al 2004) .
In Areas around Lake Mburo National Park ,large wild
animals wander in close proximity to human settlement . This poses
serious conflict in terms of crop damage. The integration of
conservation with other land uses is difficult where densely settled
agricultural land surrounds a protected area potentially containing
problem animals, as is the case for several parks in Africa and Asia.
The intensity of crop raiding was quantified through the use of random
crop quadrants/plots and area estimation techniques in a portion of
raided fields. The animal species concerned were documented from
observations, footprints and any other marks left behind. Three
variables were tested as predictors of damage; human population
density, distance from the park boundary and season. In this study data
is presented regarding crop loss in the different seasons of the year,
analysis of crop damage variation and animal species involved in crop
loss. A diverse assemblage of animals foraged on subsistence crops and
analysis of crop damage revealed significant crop depreciation by
wildlife( Kagoro et al 2004).
25. Hawai Pest
The apple snail, P.canaliculata, is an aquatic freshwater
snail native to South America, Originally imported to Hawai’i as pets
for the aquarium trade, they were soon introduced into wetland plots
known as “lo’s” where taro (Colocasia esculenta), an economically and
culturally significant crop, is grown. Some individuals reasoned that
the snails, being edible, could be harvested as food, and that raising
the snails along with the taro in the “Io’s” would provide income
supplemental to the taro harvest with minimum additional input. This
introduction of snails into the taro “lo’i” however, proved to be a
disaster. Farmers failed to take into account the voracity ,
reproductive potential, and rapid growth of the snails. Because of the
ideal conditions in the taro “lo’i”, the snails multiplied rapidly and
fed heavily on the taro shoots and corns in many cases, destroying a
complete crop before harvest time. Hindisight has shown that the snails
are dissipated via the irrigation system throughout the “lo’i” and then
spread to the surrounding wetland areas. Large breeding populations are
now established in wetland areas on the islands of Hawai’e, O’ahu,
Kaua’I, and Maui. Some of these wetlands are wildlife preserves with
state and federal mandates that restrict the potential methods of
eradication. Background information is provided on both P.canaliculata
and taro to fully explain the challenges and opportunities that this
situation presents (Tamaru et al 2006).
26. Chemical repellents
Chemical feeding repellents applied to ripening sunflower
might help reduce blackbird (lcteridae) damage, which is a chronic
agricultural problems from seed information harvest. However, cost are
high to develop and register new repellents for agricultural use. In
2003 and 2004, we evaluated feeding repellency of 8 pesticides
registered by the Environmental Protection Agency for use in sunflower.
Caged red-winged blackbirds (Agelaius phoeniceus) were fed unshelled
sunflower seeds treated with the following pesticides: 5 pyrethroid
insecticides, an organochlorine, an organophosphorus, and a gungicide.
Compared to untreated refernce groups, feeding rates were reduced for 4
of the 5 pyrethroid insecticides. Only the organophosphorus
(chlorpyrifos), however, significantly decreased feeding rates. More
research on repellency effects of this product in field efficacy trials
is probably warranted based on the results of our cage experiments.
Depending on timing of application, registered insecticides with
blackbird feeding repellency could provide supplemental economic
benefits to sunflower producers through dual purpose use ((Linz et al 2006).
27. Persistent organic pollutants (POPS)
Persistent organic pollutants (POPs) have spread
throughout the global environment to threaten human health and damage
ecosystems, with evidence of POPs contamination in wildlife, human
blood, and breast milk documented worldwide. Based on data from the US
Food and Drug Administration, this article provides a brief overview of
POPs residues in common foods in the USA food supply. The analysis
focuses on 12 chemical compounds now targeted for an international
phase out under the Stockholm convention on POPs. The available
information indicates that POPs residues are present in virtually all
categories of foods, including baked goods, fruit, vegetables, meat,
poultry, and dairy products. Residues of five or more persistent toxic
chemicals in a single food item are not unusual, with the most commonly
found POPs being the pesticides DDT ( and its metabolites, such as DDE)
and dieldrin. Estimated daily doses of dieldrin alone exceed the US
Environmental Protection Agency and US Agency for Toxic Substances
Disease Control reference dose for children. Given the widespread
occurrence of POPs in the food supply and the serious health risks
associated with even extremely small levels of exposure, prevention of
further food contamination must be a national health policy priority in
every country. Implementation of the Stockholm Convention will prevent
further accumulation of persistent toxic chemicals in food. Early
ratification and rapid implementation of this treaty should be an
urgent priority for all governments (Schafer et al 2002).
28. Netherland experiences
Traditionally, pink-footed geese Anser Brachyrhynchus
wintering in Denmark, the Netherlands and Belgium have used the Danish
sites only during mild winter, rapidly moving southwards in case of
cold spells. Since the 1980s, an increasing number of geese have
remained on the Danish wintering grounds despite cold spells, foraging
on pastures Because winter wheat represented a reliable and profitable
food source even in sever winter, the recent change in Agricultural
practice has enhanced the development of a new wintering strategy of
pink-footed geese, allowing a northward expansion of their winter
range. Potentially, this will increase the crop damage conflict and may
lead to further population growth ( Therkidsen et al 2000).
Enclosure trials near Huron, CA in the San Joaquin Valley
from 12 to 23 January 1999 , determine the efficacy of Flight Control
TM (50% anthraquinone) and Mesurol R (75% methiocarb) in preventing
horned lark damage to lettuce seedlings. Flight control TM (FC) and
Mesurol R were evaluated as foliar sprays at application rates of 2.79
and 2.27 kg ha-1, respectively. Horned lark damage to lettuce seedlings
treated with anthraquinone was greater (p=0.015) than for methiocarb R,
60 versus 20% , respectively, and seedlings in control plots were 100%
destroyed. While this level of damage is probably unacceptable to
lettuce growers, it should be remembered that the enclosure situation
caused an artificially high bird pressure on the crop. Further studies
in open fields under a more normal bird pressure are warranted ( York et al 2000).
29. Ozone injury
Incidence and severity of visible foliar ozone injury on
cutleaf coneflower (Rudbeckia laciniata L.) and crown-bread (Verbesina
Occidentalis Walt). Were determined .It is thus a matter of
consideration that zone injury may harm vegetation harmed by browsing
or even cutting. Ozone injury was greatest on the lower leaves for both
species sampled with over 95% of the injured leaves occurring on the
lower 50% of the plant. This is the first report of foliar ozone injury
on these plant species in situ, in the Park, illustrating the great
variability in symptom expression with time, and within and between
populations ( Chappelka et al 2003).
30. Protected arrears and humans
Knowledge of conflicts between people and protected areas
is required for the design of sustainable conservation strategies for
the management of most protected areas. The study identifies the causes
of conflicts between local people and the Benous Wildlife Conservation
Area (BWCA), which includes the Benous National Park, In northern
Cameroon. Informal interviews and questionnaires were administered to
114 households in three communities, and to 17 park staff and 7
professional hunting guides from July –October 1997. Crop damage
affected 86% of the surveyed household, with 31% of crop income lost on
average, and with the damage varying significantly between communities.
Elephants, baboons, patas monkeys. Warthogs and green parrots accounted
for 97% of crop damage, with the staple food maize and millet being
most affected. Of the respondents 27% experienced livestock
depredation, with 18% of livestock income lost on average. The civet
cat was the main predator. The involvement of local people in illegal
activities, their lack of access to natural resources, and damage by
wildlife were identified as principal causes of conflicts. Local
people, park staff and professional hunting guides had diverse and
differing perceptions about the causes of the conflicts and made
various suggestions for reduction of wildlife damage including animal
scaring and controlled shooting. We conclude that, under current
wildlife policy, conflict between people and BWCA (Bonous Wildlife
Conservation area) is difficult to resolve. To reduce conflicts and
promote sustainable conservation, we suggest co-management of wildlife
involving all stakeholders, establishment of crop damage control teams,
and promotion of tangible benefits to local people. There may be a
requirement for site –specificity in management strategies (Weladji et al 2003).
31. Low technology use to avoid damages
It is suggested that an integrated, community-based, low
technological approach will be the most sustainable solution to this
conflict ( Osborn et al 2003).
Blackbirds (lcteridae) annually damage US$5-8 million of
ripening sunflower in the northern Great Plains. Baiting blackbirds
with avicide-treated rice during spring migration might reduce the
regional breeding populations. birds can be successfully baited with
avicide-treated rice placed in corn stubble (Linz et al 2003).
Plant debris accumulation is viewed as a key factor
determining small mammal abundance and potential damage in low-till
agricultural ((Stermer et al 2003) areas.
The projected total value of crop yield losses due to
wildlife damage for buffer zone villages located in Garhwal Himalaya in
about Rs.5 38 620 (US$15 389). Besides food grain, horticultural crops
i.e apple, also suffered.