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1.
Riddhika Kalle Tharmalingam Ramesh Qamar Qureshi Kalyanasundaram Sankar 《Acta theriologica》2011,56(4):335-342
Density of tiger Panthera tigris and leopard Panthera pardus was estimated using photographic capture–recapture sampling in a tropical deciduous forest of Mudumalai Tiger Reserve, southern
India, from November 2008 to February 2009. A total of 2,000 camera trap nights for 100 days yielded 19 tigers and 29 leopards
within an intensive sampling area of 107 km2. Population size of tiger from closed population estimator model Mb Zippin was 19 tigers (SE = ±0.9) and for leopards Mh Jackknife estimated 53 (SE = ±11) individuals. Spatially explicit maximum likelihood and Bayesian model estimates were 8.31
(SE = ±2.73) and 8.9 (SE = ±2.56) per 100 km2 for tigers and 13.17 (SE = ±3.15) and 13.01 (SE = ±2.31) per 100 km2 for leopards, respectively. Tiger density for MMDM models ranged from 6.07 (SE = ±1.74) to 9.72 (SE = ±2.94) per 100 km2 and leopard density ranged from 13.41 (SE = ±2.67) to 28.91 (SE = ±7.22) per 100 km2. Spatially explicit models were more appropriate as they handle information at capture locations in a more specific manner
than some generalizations assumed in the classical approach. Results revealed high density of tiger and leopard in Mudumalai
which is unusual for other high density tiger areas. The tiger population in Mudumalai is a part of the largest population
at present in India and a source for the surrounding Reserved Forest. 相似文献
2.
Estimating density of elusive carnivores with capture–recapture analyses is increasingly common. However, providing unbiased
and precise estimates is still a challenge due to uncertainties arising from the use of (1) bait or lure to attract animals
to the detection device and (2) ad hoc boundary-strip methods to compensate for edge effects in area estimation. We used photographic-sampling
data of the Malagasy civet Fossa fossana collected with and without lure to assess the effects of lure and to compare the use of four density estimators which varied
in methods of area estimation. The use of lure did not affect permanent immigration or emigration, abundance and density estimation,
maximum movement distances, or temporal activity patterns of Malagasy civets, but did provide more precise population estimates
by increasing the number of recaptures. The spatially-explicit capture–recapture (SECR) model density estimates ±SE were the
least precise as they incorporate spatial variation, but consistent with each other (Maximum likelihood-SECR = 1.38 ± 0.18,
Bayesian-SECR = 1.24 ± 0.17 civets/km2), whereas estimates relying on boundary-strip methods to estimate effective trapping area did not incorporate spatial variation,
varied greatly and were generally larger than SECR model estimates. Estimating carnivore density with ad hoc boundary-strip
methods can lead to overestimation and/or increased uncertainty as they do not incorporate spatial variation. This may lead
to inaction or poor management decisions which may jeopardize at-risk populations. In contrast, SECR models free researchers
from making subjective decisions associated with boundary-strip methods and they estimate density directly, providing more
comparable and valuable population estimates. 相似文献
3.
Udayan Borthakur Rumi Dev Barman Chatrapati Das Ajit Basumatary Anjan Talukdar M. Firoz Ahmed Bibhab Kumar Talukdar Rupjyoti Bharali 《European Journal of Wildlife Research》2011,57(3):603-613
The Brahmaputra Valley of Assam, India, is one of the prime habitats for the endangered Royal Bengal tiger Panthera tigris tigris. With dwindling global population, estimation of the minimum number of tigers has always been a curiosity to wildlife researchers
as well as to protected area managers. In the present study, DNA-based techniques were used for identifying individual tigers
present in Orang National Park of Assam, from 57 faecal samples collected during February 2009. Orang National Park stands
as an island of a single forest patch along the north bank of river Brahmaputra. The present study confirms the presence of
17 individual tigers in Orang National Park, with five male and 12 female. DNA-based capture–recapture analysis yielded minimum
range estimate of 18 and 19 individuals, with possible overestimates of population size following two models of capture probability
in CAPWIRE. The results of our genetic counting of tigers are compared with the estimates of 19 tigers based on pugmark analysis
by the state Forest Department in 2000 and an independent capture–recapture estimate of 14 (±3.6) individuals based on photographic
identity study in 2009. Looking at high mortality of tigers in the area, with 19 reported deaths during 2000 to 2009, our
results indicate high individual turnover in the area. This study shows that Orang National Park harbours a healthy breeding
population of tigers. However, the possibility of a source-sink dynamics operating in the landscape could not be ruled out,
with possible immigration from nearby Kaziranga National Park on the south bank of Brahmaputra, which has the highest reported
density of the species in the world. 相似文献
4.
Emiliano Manzo Paola Bartolommei J. Marcus Rowcliffe Roberto Cozzolino 《Acta theriologica》2012,57(2):165-172
Evaluating presence and abundance of small carnivores is essential for their conservation. In Italy, there is scarce information
on European pine marten distribution, and no data are published on its abundance. Camera traps have been widely used to estimate
population density applying capture–recapture models for species in which individual recognition is possible. Here we estimate
the abundance of European pine martens in central Italy using camera trapping and a model that allows the estimation of population
density without the need for individual recognition Rowcliffe et al. (Anim Conserv 11:185–186, 2008). Camera trapping was also used to evaluate habitat use patterns by martens. Fifteen camera traps were deployed in 90 placements
for 15 days each, for a total of 1,334 camera days. Pine martens were captured in 24% of camera trap placements with a mean
trap success rate of 0.33 photographs per camera placement. Estimated pine marten population density in the study area was
0.34 individuals km−2. Marten trap rate was not strongly associated with any habitat type, although there were trends towards lower probability
of records at locations with high coverage of cultivated fields and higher probability of records at locations with high coverage
of human-made woodland. The results suggest that pine martens in this area are not confined to wooded habitat. To our knowledge,
this study is the first application of the Rowcliffe et al. (Anim Conserv 11:185–186, 2008) method to a wild carnivore population and, furthermore, the first estimation of population density of pine martens in Italy. 相似文献
5.
《Mammalian Biology》2014,79(4):254-258
Low density occurrence of large carnivore species and direct hunting of predators and prey make carnivore conservation complex. Vital baseline information on population status of large carnivores is still deficient in most forests of eastern Himalaya, which are known to be the biodiversity hotspots. To fill this information gap, we estimated the large carnivore population status and abundance in an intricate eastern Himalayan lowland tropical forest in Pakke Tiger Reserve, Arunachal Pradesh. Population status and abundance estimates of tigers and leopards were made through individual identification using closed capture-recapture sampling. To estimate the dhole abundance photographic encounter rate was used. For individually non-identifiable species photographic rate seemed to correlate well with animal abundance. The estimated tiger and leopard density through 1/2 MMDM was 2.14 ± 0.04/100 km2 and 2.99 ± 1.13/100 km2 respectively. Maximum likelihood estimates shows density of tiger 1.86 ± 0.7 and for leopard 2.82 ± 1.2.The estimated dhole abundance was (N) 10.6 ± 0.94, and density 6.62 ± 0.58 individuals in 100 km2. Further, occupancy estimation of large carnivores may be tried along with assessing the comparative efficacy of other population estimation methods to establish better monitoring methods for this region. 相似文献
6.
Manjari Roy Qamar Qureshi Dipanjan Naha Kalyanasundaram Sankar Rajesh Gopal Yadvendradev Vikramsinh Jhala 《Population Ecology》2016,58(1):81-89
Conserving large populations with unique adaptations is essential for minimizing extinction risks. Sundarban mangroves (>10,000 km2) are the only mangrove inhabited by tigers. Baseline information about this tiger population is lacking due to its man-eating reputation and logistic difficulties of sampling. Herein, we adapt photographic capture-mark-recapture (CMR) and distance sampling to estimate tiger and prey densities. We placed baited camera stations in a typical mangrove in 2010 and 2012. We used telemetry based tiger home-range radius (5.73 km, SE 0.72 km) to estimate effective trapping area (ETA). An effort of 407 and 1073 trap nights were exerted to photocapture 10 and 22 unique tigers in 2010 and 2012. We accounted for use of bait by modelling behaviour and heterogeneity effects in program MARK and secr package in program R. Using traditional CMR, tiger number was estimated at 11 (SE 2) and density at 4.07 (SE range 3.09–5.17) in 2010 while in 2012, tiger number was 24 (SE 3) and density 4.63 (SE range 3.92–5.40) tigers/100 km2. With likelihood based spatially explicit CMR, tiger densities were estimated at 4.08 (SE 1.51) in 2010 and 5.81 (SE 1.24) tigers/100 km2 in 2012. Using distance sampling along water channels, we estimated chital density at 5.24/km2, SE 1.23 which could potentially support 4.68 tigers/100 km2 [95 % CI (3.92, 5.57)]. Our estimates suggest that Sundarban tiger population is one of the largest in the world and therefore merits high conservation status. 相似文献
7.
Abishek Harihar Bivash Pandav Surendra P. Goyal 《European Journal of Wildlife Research》2009,55(2):97-105
Presence of human settlements in most protected areas has forced tigers (Panthera tigris) to share space with humans. Creation of inviolate space for tigers in areas with high human densities is often daunting
and requires hard political sacrifices. We conducted this study from 2004 to 2007 in the Chilla range of Rajaji National Park,
along the northwestern portion of the Terai-Arc Landscape in the Indian subcontinent. Our objective was to document the recovery
of prey and tiger populations following the resettlement of 193 gujjar (pastoralists with large buffalo holdings) families. We used distance sampling to estimate density of wild ungulate prey
and camera traps to estimate tiger density. The study area supported ∼66 ungulates/km2, with chital (Axis axis) and sambar (Cervus unicolor) contributing >91%. While prey densities did not vary across 3 years, an increase in proportion of chital fawns was observed
following the near complete removal of livestock. We also documented an increase in the density of tigers (from three to five tigers per 100 km2), probably due to immigrating tigers from nearby Corbett Tiger Reserve. A high turnover of individual tigers was observed
during the study. With photographic evidence of breeding tigers in Chilla range, we believe that this area could serve as
a source population from where tigers can colonize adjoining forests across River Ganga. It is therefore concluded that securing
the connectivity between forests on the east and west bank of Ganga through the tenuous Chilla-Motichur corridor assumes significance
for long-term persistence of tigers within this landscape. 相似文献
8.
Reuben Clements Darmaraj Mark Rayan Abdul Wahab Ahmad Zafir Arun Venkataraman Raymond Alfred Junaidi Payne Laurentius Ambu Dionysius Shankar Kumar Sharma 《Biodiversity and Conservation》2010,19(4):1115-1136
Three of Malaysia’s endangered large mammal species are experiencing contrasting futures. Populations of the Sumatran rhino
(Dicerorhinus sumatrensis) have dwindled to critically low numbers in Peninsular Malaysia (current estimates need to be revised) and the state of Sabah
(less than 40 individuals estimated). In the latter region, a bold intervention involving the translocation of isolated rhinos
is being developed to concentrate them into a protected area to improve reproduction success rates. For the Asian elephant
(Elephas maximus), recently established baselines for Peninsular Malaysia (0.09 elephants/km2 estimated from one site) and Sabah (between 0.56 and 2.15 elephants/km2 estimated from four sites) seem to indicate globally significant populations based on dung count surveys. Similar surveys
are required to monitor elephant population trends at these sites and to determine baselines elsewhere. The population status
of the Malayan tiger (Panthera tigris jacksoni) in Peninsular Malaysia, however, remains uncertain as only a couple of scientifically defensible camera-trapping surveys
(1.66 and 2.59 tigers/100 km2 estimated from two sites) have been conducted to date. As conservation resources are limited, it may be prudent to focus
tiger monitoring and protection efforts in priority areas identified by the National Tiger Action Plan for Malaysia. Apart
from reviewing the conservation status of rhinos, elephants and tigers and threats facing them, we highlight existing and
novel conservation initiatives, policies and frameworks that can help secure the long-term future of these iconic species
in Malaysia. 相似文献
9.
Pedro Bernardo Sarmento Joana P. Cruz Catarina I. Eira Carlos Fonseca 《European Journal of Wildlife Research》2010,56(1):59-66
Using camera-trapping techniques, the present study, conducted from 2005 to 2007, provides common genet abundance estimates
in Serra da Malcata Nature Reserve (central-eastern Portugal). We estimated genet abundance using the software CAPTURE. It
was possible to obtain a capture success of 1.49 captures/100 trap-nights. Considering the heterogeneity model (Mh), which presents higher biological significance, the estimated density varied between 0.50 (95% CI = 0.43–0.56 genets/km2) to 0.92 (95% CI = 0.87–0.97 genets/km2) genets/km2 with an average density value of 0.70 genets/km2 (95% CI = 0.58–0.82 genets/km2). These estimates emphasized this technique as a reliable method for assessing average genet density over large spatial scales
and for monitoring future changes in genet numbers. In terms of habitat selection, genets selected Quercus rotundifolia and Arbutus unedo woodlands and avoided Erica spp. and Cistus ladanifer scrubland and Eucalyptus stands. Considering the landscape heterogeneity outside the reserve, our study emphasizes the importance of the protected
area for small carnivore conservation. 相似文献
10.
Analyses of stopover parameters of migrating birds with Cormack–Jolly–Seber (CJS) capture–recapture models often suffer from
low precision due to sparse data sets. Low recapture rates result in low power to detect violations of the underlying assumptions
and factors influencing stopover behaviour. We studied stopover behaviour of Palearctic migrant passerines in an oasis in
Mauritania, West Africa. Using capture–recapture data and systematic observations of colour-ringed birds, we analysed the
effect of increased sample size on probability of stay and recapture probability and the influence of a possible trap response
on these parameters. We analysed capture–recapture data with the conventional CJS model and compared the results with those
from a multistate model using in addition resighting data. The analyses including resighting data resulted in a higher precision
of the estimates of the probabilities of stay compared to analyses using only capture–recapture data of the same individuals.
Moreover, the power to detect transients was substantially enhanced. Capture had no effect on the estimates of probability
to stay and recapture probability; birds did not leave the stopover site or avoid nets as a reaction to capture. The estimates
of probability of stay were up to 15.7% higher when resighting data were included, probably due to the higher power to detect
transients and the elimination of the bias induced by non-random temporary emigration when both data types are considered.
As a consequence, stopover duration would have been underestimated when only the capture–recapture data were available. We
conclude that additional resightings of colour ringed birds can produce more accurate results needed for enhancing our understanding
of stopover ecology of migrants.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.
From the Swiss Ornithological Institute project on bird migration across the Sahara. 相似文献
11.
Tigers (Panthera tigris) today face multiple threats to their survival in the form of habitat loss, poaching, depletion of wild prey through illegal hunting and loss of connectivity between populations. Monitoring of tigers is crucial to evaluate their status and react adaptively to management problems. Though camera traps are becoming increasingly popular with researchers enumerating cryptic and elusive animals, they have not been embedded in the regular management activities of tiger reserves. Tiger monitoring, though an important part of the management, is usually implemented using the unreliable pugmark approach. Camera trap-based studies are few, usually of short duration, and are generally conducted by individual scientists and organizations. In this study, we integrate photographic mark–recapture with the routine activity of searching and locating tigers for tourist viewing by the park management in meadows of Kanha Tiger Reserve which form a part of the tourism zone. We validate the density estimates from “tiger search approach” against those obtained from camera trapping and radio-telemetry conducted in conjunction in the same area. Tiger density (\( \hat{D} \) (SE [\( \hat{D} \)]) per 100 km2 for camera traps and tiger search, respectively, was estimated at 12.0 (1.95) and 12.0 (1.76) when effective trapping area was estimated using the half mean maximum distance moved (½ MMDM), 7.6 (1.94) and 7.5 (1.97) using the home range radius, 7.3 (1.49) and 7.5 (1.97) with the full MMDM, and 8.0 (3.0) and 6.88 (2.39) with the spatial likelihood method in Program DENSITY 4.1. Camera trapping, however, was five times more expensive than the tiger search method. Our study suggests that “tiger search approach” can be used as a regular monitoring tool in the tourism zones of tiger reserves, where often most of the source populations are located. 相似文献
12.
The use of camera traps in ecology helps affordably address questions about the distribution and density of cryptic and mobile species. The random encounter model (REM) is a camera‐trap method that has been developed to estimate population densities using unmarked individuals. However, few studies have evaluated its reliability in the field, especially considering that this method relies on parameters obtained from collared animals (i.e., average speed, in km/h), which can be difficult to acquire at low cost and effort. Our objectives were to (1) assess the reliability of this camera‐trap method and (2) evaluate the influence of parameters coming from different populations on density estimates. We estimated a reference density of black bears (Ursus americanus) in Forillon National Park (Québec, Canada) using a spatial capture–recapture estimator based on hair‐snag stations. We calculated average speed using telemetry data acquired from four different bear populations located outside our study area and estimated densities using the REM. The reference density, determined with a Bayesian spatial capture–recapture model, was 2.87 individuals/10km2 [95% CI: 2.41–3.45], which was slightly lower (although not significatively different) than the different densities estimated using REM (ranging from 4.06–5.38 bears/10km2 depending on the average speed value used). Average speed values obtained from different populations had minor impacts on REM estimates when the difference in average speed between populations was low. Bias in speed values for slow‐moving species had more influence on REM density estimates than for fast‐moving species. We pointed out that a potential overestimation of density occurs when average speed is underestimated, that is, using GPS telemetry locations with large fix‐rate intervals. Our study suggests that REM could be an affordable alternative to conventional spatial capture–recapture, but highlights the need for further research to control for potential bias associated with speed values determined using GPS telemetry data. 相似文献
13.
Digpal Singh Gour Jyotsna Bhagavatula Maradani Bhavanishankar Patlolla Anuradha Reddy Jaya A. Gupta Mriganka Shekhar Sarkar Shaik Mohammed Hussain Segu Harika Ravinder Gulia Sisinthy Shivaji 《PloS one》2013,8(7)
Background
Tiger populations are dwindling rapidly making it increasingly difficult to study their dispersal and mating behaviour in the wild, more so tiger being a secretive and solitary carnivore.Methods
We used non-invasively obtained genetic data to establish the presence of 28 tigers, 22 females and 6 males, within the core area of Pench tiger reserve, Madhya Pradesh. This data was evaluated along with spatial autocorrelation and relatedness analyses to understand patterns of dispersal and philopatry in tigers within this well-managed and healthy tiger habitat in India.Results
We established male-biased dispersal and female philopatry in tigers and reiterated this finding with multiple analyses. Females show positive correlation up to 7 kms (which corresponds to an area of approximately 160 km2) however this correlation is significantly positive only upto 4 kms, or 50 km2 (r = 0.129, p<0.0125). Males do not exhibit any significant correlation in any of the distance classes within the forest (upto 300 km2). We also show evidence of female dispersal upto 26 kms in this landscape.Conclusions
Animal movements are important for fitness, reproductive success, genetic diversity and gene exchange among populations. In light of the current endangered status of tigers in the world, this study will help us understand tiger behavior and movement. Our findings also have important implications for better management of habitats and interconnecting corridors to save this charismatic species. 相似文献14.
C. Hebeisen J. Fattebert E. Baubet C. Fischer 《European Journal of Wildlife Research》2008,54(3):391-401
We estimated wild boar abundance and density using capture–resight methods in the western part of the Canton of Geneva (Switzerland)
in the early summer from 2004 to 2006. Ear-tag numbers and transmitter frequencies enabled us to identify individuals during
each of the counting sessions. We used resights generated by self-triggered camera traps as recaptures. Program Noremark provided
Minta–Mangel and Bowden’s estimators to assess the size of the marked population. The minimum numbers of wild boars belonging
to the unmarked population (juveniles and/or piglets) were added to the respective estimates to assess total population size.
Over the 3 years, both estimators showed a stable population with a slight diminishing tendency. We used mean home range size
determined by telemetry to assess the sampled areas and densities. Mean wild boar population densities calculated were 10.6 individuals/km2 ± 0.8 standard deviation (SD) and 10.0 ind/km2 ± 0.6 SD with both estimators, respectively, and are among the highest reported from Western Europe. Because of the low proportion
of marked animals and, to a lesser extent, of technical failures, our estimates showed poor precision, although they displayed
similar population trends compared to the culling bag statistics. Reported densities were consistent with the ecological conditions
of the study area. 相似文献
15.
16.
P. Anuradha Reddy A. Kumaraguru P. Raghuveer Yadav A. Ramyashree Jyotsna Bhagavatula Sisinthy Shivaji 《European Journal of Wildlife Research》2011,57(3):517-522
A decade back, almost 300,000 km2 of forests in India were estimated to be potential tiger habitat. But consistent degradation and unsustainable anthropogenic
pressures have adversely affected tiger presence in most of the forests outside the better protected tiger reserves. Here
we use Geographic Information System data to analyze the degree of vegetation loss and landscape changes over the last decade
(1998–2006), and ascertain the presence of tigers in a degraded forest like the Kawal Wildlife Sanctuary, Andhra Pradesh,
India, by non-invasive fecal DNA analysis. Vegetation cover maps show a clear degradation of the sanctuary within a decade.
DNA analysis of scat samples reveals tiger presence in areas where closed dense forest canopy has persisted with minimal human
disturbance during the last decade. 相似文献
17.
A common task for conservation biologists and ecologists is to establish how many individuals there are in a population, usually
within a defined area of habitat. Estimates of both absolute and relative population sizes are widely used in many aspects
of population conservation and management. Mark–recapture studies are appropriate for estimating the absolute population sizes
of a wide range of animals, in both open and closed populations, while relative abundances can be estimated from a variety
of survey methods. Relative abundances are often used in a comparative way to compare both population size and fluctuations
in abundance. Here, we used transect counts and capture–recapture studies to estimate the relative abundances and population
sizes of a specialist butterfly, Theclinesthes albocincta (Lycaenidae) in three habitat fragments, over two consecutive years. The sizes of the three populations differed significantly
between sites and were highly variable between years. One population was extremely small and is likely to become locally extinct.
We found that estimates of relative abundance were highly correlated with estimates of population size (r
2 = 0.88, P = 0.017) derived from the open population models. The combination of transect counts and capture–recapture studies used in
this study appears to be a very informative tool for the conservation and management of this butterfly species and could be
extended to other insects. 相似文献
18.
Chandan Surabhi Das 《European Journal of Wildlife Research》2012,58(1):205-214
The Sundarban of India and Bangladesh is the only mangrove reserve forest in the world inhabited by the tiger (Panthera tigris). Tigers in the Sundarban mangrove are widely known for frequently straying into the surrounding reclaimed areas. Data collected
from household village survey and documents of the Forest Department show that tiger straying incidents happen throughout
the year, but most of them occurred during 3 months (Dec–Feb) of the winter season (42%) followed by 3 months (July–Sept)
of the monsoon season (31%). 84.22% of cases have been reported from 21 villages of five affected blocks of Sundarban. In
most cases, tigers resorted to cattle lifting or poultry feeding. Only in 8.9% of the cases were human beings attacked or
killed. Majority of the straying tigers (68.46%) were male. In most cases (78.9%) strayed tigers were aged and 22% of these
were partly injured. 96.05% straying occurs during night. This study also aims at exploring the causes of frequent straying,
livestock and human casualties as a result of conflict and retaliation killing of tigers. Straying frequency is correlated
negatively with the width of the creeks or rivers in the village side and no relationship is identified with the area of the
forest block as well as natural prey abundance. Overall, improved nylon fencing, increased patroling, establishment of the
Forest Protection Committee (FPC) and the Eco Development Committee (EDC) are not associated with reduction of straying frequency
as well as livestock losses to tiger straying. 相似文献
19.
P. Anuradha Reddy A. Kumaraguru Jyotsna Bhagavatula Digpal Singh Gour M. Bhavanishankar M. Shekhar Sarkar K. Harika Sk. Md. Hussain S. Shivaji 《Conservation Genetics》2012,13(3):779-787
Tiger, being a solitary and territorial animal, often tends to move out of protected areas into the surrounding forests. This
is especially true in the case of sub-adult animals leading to escalating conflicts and deaths in the surrounding human-dominated
landscapes. Unless adequately protected against various human activities, such corridors and surrounding forests will soon
disappear, trapping the animals within protected areas with resultant local extinctions. In this paper we ascertain tiger
presence, occupancy and numbers in one such partially protected area, the Sathyamangalam forest, located close to better known
tiger reserves in India, through non-invasive faecal DNA analysis. Here we highlight the potential of Sathyamangalam as a
tiger habitat. Tiger positive faecal samples were considered as evidence to establish occupancy in two different parts of
Sathyamangalam, reserve forest and wildlife sanctuary. We collected 103 faecal samples out of which 69 were tiger positive.
Species occupancy (psi), was 0.672 (±0.197) with a detection probability of 0.2 (±0.06) in the wildlife sanctuary area; while
psi was 0.72 (±0.2) with detection probability of 0.212 (±0.6) in the reserve forest. Further, number of males and females,
as determined in our study, was close to the ideal sex ratio in a healthy forest with good prey abundance. This study also
highlights the presence of more females in the reserve forest (n = 10) than the wildlife sanctuary (n = 3) possibly indicating lesser disturbance and more prey availability. We recommend that the reserve forest to the north
of Sathyamangalam wildlife sanctuary be declared as a tiger reserve. The wildlife sanctuary could serve as a buffer zone between
this reserve and Sathyamangalam town which lies to the south of the forest. Proper protection of Sathyamangalam will go a
long way in saving the entire landscape and tigers of the Western Ghats of India. 相似文献
20.
Protection from fishing generally results in an increase in the abundance and biomass of species targeted by fisheries within
marine reserve boundaries. Natural refuges such as depth may also protect such species, yet few studies in the Indo Pacific
have investigated the effects of depth concomitant with marine reserves. We studied the effects of artisanal fishing and depth
on reef fish assemblages in the Kubulau District of Vanua Levu Island, Fiji, using baited remote underwater stereo-video systems.
Video samples were collected from shallow (5–8 m) and deep (25–30 m) sites inside and outside of a large old marine reserve
(60.6 km2, 13 years old) and a small new marine reserve (4.25 km2, 4 years old). Species richness tended to be greater in the shallow waters of the large old reserve when compared to fished
areas. In the deeper waters, species richness appeared to be comparable. The difference in shallow waters was driven by species
targeted by fisheries, indicative of a depth refuge effect. In contrast, differences in the abundance composition of the fish
assemblage existed between protected and fished areas for deep sites, but not shallow. Fish species targeted by local fisheries
were 89% more abundant inside the large old reserve than surrounding fished areas, while non-targeted species were comparable.
We observed no difference in the species richness or abundance of species targeted by fisheries inside and outside of the
small new reserve. This study suggests that artisanal fishing impacts on the abundance and species richness of coral reef
fish assemblages and effects of protection are more apparent with large reserves that have been established for a long period
of time. Observed effects of protection also vary with depth, highlighting the importance of explicitly incorporating multiple
depth strata in studies of marine reserves. 相似文献