Line Transect Methodology Research Articles

Abundance Determination of Large Mammals with Distance Sampling Perspective, the Case of Elephants of the Mole National Park (MNP) of Ghana

Distance sampling with line transect method has been applied by many researchers to monitor and observe varied animals and plants with the aim of determining the population density and or abundance of animals. The application of this method has not received the needed attention in Ghana, in particular to monitor, observe, and estimate the densities and abundance of animals and plants in the game reserves of the Mole National Park (MNP) is not without exception and the statistics of these are always reported based on guesses and without any scientific proof. This study has seen the application of line transect methodology in the MNP in which the abundance estimates are statistically determined with both the classical and Bayesian philosophies of statistical approaches. An alternative means of detectability estimation using the total probability concept has been established to enhance the probability of detection of a rare and elusive population of large mammals. In performing statistical investigations on rare and elusive population, it appears insufficient to model from the classical perspective, the use of PRIOR knowledge as seen in the Bayesian context cannot be underestimated. This study proposed that the concept of Total Probability with prior knowledge of animals and plants in line transect surveys must be well embraced, Periodic censuss must be conducted regularly to help in establishing the rate of extinction of units of interest in wildlife and Distance sampling data with line transect sampling methodology need not be analysed using only the classical reasoning. Attention must be given to the existence and availability of prior knowledge of the units under study.

Winter distribution and abundance of humpback whales (Megaptera novaeangliae) off Northeastern Brazil

The Brazilian coast is recognised as a Southern Hemisphere humpback whale (Megaptera novaeangliae) wintering ground (IWC breeding stock ‘A’). The northeastern coast of Brazil was an important whaling ground in the 20th century. Shipboard sighting surveys were conducted in this area to evaluate large whales’ distribution and density in 1999 and 2000. Humpback whale sightings (n = 81, 153 individuals) were recorded using line transect methodology. Data from the 2000 survey were used to estimate abundance over the continental shelf from 5 to 12°S (20,040km2 ). A total of 872.1km were surveyed on effort. Humpback whales were distributed from nearshore to the 800m isobath, but 93.5% of sightings were recorded shoreward of the 300m isobath. The relatively high density off northeastern Brazil suggests that the species is reoccupying historical areas of distribution and the presence of newborn individuals indicates that calving and nursing occur in the area. The hazard rate model best fit perpendicular distance data. Abundance was estimated at 628 individuals (CV = 0.335, 95% CI = 327-1,157). This estimate probably corresponds to only a portion of the breeding population. Therefore, additional studies must be conducted to estimate the total size of the humpback whale population wintering off Brazil.

Summer distribution of harbour porpoise (Phocoena phocoena) in the German North Sea and Baltic Sea

Current plans to utilise German offshore waters as sites for windmill parks as well as ongoing investigation of potential areas to implement Natura 2000 have led to an increased research effort on local marine mammal populations. The aim of this study was to determine the spatial distribution of harbour porpoises in the German part of the North Sea and Baltic Sea. Aerial surveys were conducted from May to August 2002 using standard line-transect methodology. A total of 21 days of aerial surveying covered 8,072km tracks on effort; 4,908km were conducted in conditions of good visibility. A total of 785 harbour porpoises (488 sightings) were seen; 597 animals (427 sightings) were detected in conditions of good visibility. The study area was divided into a grid of 3 minute latitude by 6 minute longitude squares. Porpoise relative abundance and distribution were estimated as the number of animals per km on effort in each square. The results showed that in the North Sea, the highest number of porpoises per km was observed in the northeastern part of the surveyed area, close to the Danish border and in the area of Amrum Outerbank. In the Baltic Sea, the highest relative abundance of porpoises was seen in the Pomeranian Bight between the island of Rügen and the Polish border. Pod size in the Baltic was larger than in the North Sea. The aerial surveys were continued in 2003 in order to collect more information on temporal and spatial distribution of harbour porpoise and its intra and inter-annual variability in German waters. These data will serve as a baseline for management decisions.

Southern Hemisphere Breeding Stock D humpback whale population estimates from North West Cape, Western Australia

Estimates of the abundance of Breeding Stock D humpback whales (Megaptera novaeangliae) are key to the conservation and management of what is thought to be one of the largest populations of the species. Five years (2000, 2001, 2006, 2007 and 2008) of aerial surveys carried out over an eight-year period at North West Cape (Western Australia) using line transect methodology allowed trends in whale numbers to be investigated, and provided a base for comparison with estimates made approximately 400km south at Shark Bay (Western Australia). A total of 3,127 whale detections were made during 74 surveys of the 7,043km2 study area west of NWC. Pod abundance for each flight was computed using a HorvitzThompson like estimator and converted to an absolute measure of abundance after corrections were made for estimated mean cluster size, unsurveyed time, swimming speed and animal availability. Resulting estimates from the migration model of best fit with the most credible assumptions were 7,276 (CI = 4,993–10,167) for 2000, 12,280 (CI = 6,830–49,434) for 2001, 18,692 (CI = 12,980–24,477) for 2006, 20,044 (CI = 13,815–31,646) for 2007, and 26,100 (CI = 20,152–33,272) for 2008. Based on these data, the trend model with the greatest r2 was exponential with an annual increase rate of 13% (CI = 5.6%–18.1%). While this value is above the species’ estimated maximum plausible growth rate of 11.8%, it is reasonably close to previous reports of between 10–12%. The coefficient of variation, however, was too large for a reliable trend estimate. Perception bias was also not accounted for in these calculations. Based on a crude appraisal which yielded an estimated p(0) of 0.783 (from independent observer effort, CV = 0.973), the 2008 humpback population size may be as large as 33,300. In conclusion, the work here provides evidence of an increasing Breeding Stock D population, but further surveys are necessary to confirm whether the population is indeed increasing at its maximum rate.

Comparison of Nesting site preferences of Ratufa indica indica in Umblebyle Range Forest 2021 and 2022

Ratufa indica indica is a gaint arboreal squirrel species endemic to India, common to Western Ghats. The study is designed to compare Nesting site preferences of Ratufa indica indica conducted in 2022 with the studies from 2021 in the Umblebyle range forest of Shimoga. The study uses Line transect methodology which was plotted using Arc GIS that includes 20 line transects of 47.7 kms covering a total area of 8350.89ha. Study from 2021 showed a total of 406 dreys (nests) constructed on 385 trees while the one from 2022 showed a total of 455 dreys constructed on 415 trees. The nest trees from 2021 belonged to 20 families and 41 species while the one from 2022 belonged to 22 families and 36 species with highest preference Family Fabaceae that included 12 tree species in 2021 and 8 tree species in 2022 respectively. Terminalia paniculata was most preferred tree species that included 84 and 85 trees in 2021 and 2022 respectively.The study also showed the animal preferred average tree height of 16.18 ± 3.43 (2021) and 18.05 ± 3.485m (2022). The studies further showed preference of Ratufa indica indica for deciduous trees over semi-evergreen and evergreen trees.

Monitoring Abundance and Distribution of Northern Gannets Morus bassanus in Western Iberian Waters in Autumn by Aerial Surveys

Several North Atlantic breeding seabirds, such as the Northern Gannet Morus bassanus, use Western Iberian Waters for wintering and migration. In this study, we aimed at producing absolute population estimates of post-breeding Gannets and evaluating the importance of the study area within the species' migration range. We performed six aerial surveys in September and/or October each year between 2010 and 2015, covering 74,840 km2 in total. Using line transect methodology, 3,672 Gannet sightings were recorded along 10,496.3 nautical miles (nm). Immature individuals and adults comprised approximately 87% of all sightings. Using Distance sampling, overall abundance was estimated at 89,930 birds, ranging from 58,010 individuals in 2014 to 128,140 in 2015. The highest densities per sector areas were recorded in the North and Centre sectors whereas the lowest densities were registered in the Galicia sector, the Spanish region within the study area. Gannets were mostly present in shallow shelf waters of the continental shelf, particularly between 3 and 20 nautical miles offshore. Habitat suitability models for Gannets in the study area were tested using several eco-geographical variables and chlorophyll concentrations were found to contribute most to explaining annual Gannet occurrence probabilities. A global interannual spatial analysis demonstrated the core areas for conservation of the Northern Gannet in Western Iberian Waters. Moreover, our results demonstrate that Western Iberian waters are used by almost 10% of the global Northern Gannet population, corroborating the existence of seabird hotspots during the non-breeding period, along migration corridors and at their wintering grounds.—Araújo, H., Correia Rodrigues, P., Bastos-Santos, J., Ferreira, M., Pereira, A., Martínez-Cedeira, J., Vingada, J. & Eira, C. (2022). Monitoring abundance and distribution of Northern Gannets Morus bassanus in Western Iberian Waters in autumn by aerial surveys. Ardeola, 69: 179-202.

Intra-season variations in distribution and abundance of humpback whales in the West Antarctic Peninsula using cruise vessels as opportunistic platforms.

Fine‐scale knowledge of spatiotemporal dynamics in cetacean distribution and abundance throughout the Western Antarctic Peninsula (WAP) is sparse yet essential for effective ecosystem‐based management (EBM). Cruise vessels were used as platforms of opportunity to collect data on the distribution and abundance of humpback whales (Megaptera novaeangliae) during the austral summer of 2019/2020 in a region that is also important for the Antarctic krill (Euphausia superba) fishery, to assess potential spatiotemporal interactions for future use in EBM. Data were analyzed using traditional design‐based line transect methodology and spatial density surface hurdle models fitted using a set of physical environmental covariates to estimate the abundance and distribution of whales in the area, and to describe their temporal dynamics. Our results indicate a rapid increase in humpback whale abundance in the Bransfield and Gerlache Straits through December, reaching a stable abundance by mid‐January. The distribution of humpback whales appeared to change from a patchier distribution in the northern Gerlache Strait to a significantly concentrated presence in the central Gerlache and southern Bransfield Straits, followed by a subsequent dispersion throughout the area. Abundance estimates agreed well with previous literature, increasing from approximately 7000 individuals in 2000 to a peak of 19,107 in 2020. Based on these estimates, we project a total krill consumption of between 1.4 and 3.7 million tons based on traditional and contemporary literature on per capita krill consumption of whales, respectively. When taken in the context of krill fishery catch data in the study area, we conclude that there is minimal spatiotemporal overlap between humpback whales and fishery activity during our study period of November–January. However, there is potential for significant interaction between the two later in the feeding season, but cetacean survey efforts need to be extended into late season in order to fully characterize this potential overlap.

Distribution and Abundance of Marine Mammals in the Estuarine Waters of the Piscataqua River, Maine, USA

The estuaries and tidal rivers of the Gulf of Maine have rarely been surveyed systematically for marine mammals. We report here on three years of survey data, 2017 to 2019. This study employed a shipboard visual line-transect methodology study design, collecting data on marine mammals in the lower Piscataqua River, which is confluent with the Gulf of Maine. Marine mammal species observed most often were harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus), with a resulting in-water density estimate of 1.02 seals/km2 and an abundance estimate of seven harbor seals and one gray seal (CV = 19.3%) in the survey area. Seals were present in all months of the year. No live pups were detected. Harbor porpoises (Phocoena phocoena) and minke whales (Balaenoptera acutorostrata) were also observed, but the sightings (6 harbor porpoises; 7 minke whales) did not yield enough data to estimate density or abundance. The minke whales were present during August and September 2018, concurrent with an influx of Atlantic menhaden (Brevoortia tyrannus), a prey species. The consistent albeit relatively low marine mammal species sightings and abundances suggest that the lower Piscataqua River is used regularly by a relatively small number of harbor and gray seals, although not for pupping, and occasionally by harbor porpoises and by foraging minke whales. This is the first study of its kind in an estuarine environment in the Gulf of Maine.

Small Cetacean in a Human High-Use Area: Trends in Harbor Porpoise Abundance in the North Sea Over Two Decades

The North Sea is one of the most heavily used shelf regions worldwide with a diversity of human impacts, including shipping, pollution, fisheries, and offshore constructions. These stressors on the environment can have consequences for marine organisms, such as our study species, the harbor porpoise (Phocoena phocoena), which is regarded as a sentinel species and hence has a high conservation priority in the European Union (EU). As EU member states are obliged to monitor the population status, the present study aims to estimate trends in absolute harbor porpoise abundance in the German North Sea based on almost two decades of aerial surveys (2002–2019) using line-transect methodology. Furthermore, we were interested in trends in three Natura2000 Special Areas of Conservation (SACs), which include the harbor porpoise as designated feature. Trends were estimated for each SAC and two seasons (spring and summer) as well as the complete area of the German North Sea. For the trend analysis we applied a Bayesian framework to a series of replicated visual surveys, allowing to propagate the error structure of the original abundance estimates to the final trend estimate and designed to deal with spatio-temporal heterogeneity and other sources of uncertainty. In general, harbor porpoise abundance decreased in northern areas and increased in the south, such as in the SAC Borkum Reef Ground. A particularly strong decline with a high probability (94.9%) was detected in the core area and main reproduction site in summer, the SAC Sylt Outer Reef (−3.79% per year). The overall trend for the German North Sea revealed a decrease in harbor porpoise abundance over the whole study period (−1.79% per year) with high probability (95.1%). The assessment of these trends in abundance based on systematic monitoring should now form the basis for adaptive management, especially in the SAC Sylt Outer Reef, where the underlying causes and drivers for the large decline remain unknown and deserve further investigation, also in a regional North Sea wide context.

Distribution and abundance of dalli-type Dall’s porpoises Phocoenoides dalli migrating into waters off southeastern Hokkaido, Japan, during summer: results of 2014–2016 aerial surveys

A series of systematic aerial sighting surveys were conducted in the coastal waters off southeastern Hokkaido to reveal distribution patterns and estimate the abundance of Dall’s porpoises migrating into those waters during summers. A total of 6805.5 km was flown, and 98 porpoise schools were detected in 2014–2016. Dalli-type animals were discriminated from truei-type by logistic discriminant functions constructed based on previous sighting data, and the abundance of the dalli-type porpoise was estimated using a line-transect methodology. The estimated abundance of dalli-type Dall’s porpoises migrating into the main study area (S-block) was 134 (coefficient of variation = 0.91) in 2014, 766 (0.77) in 2015, and 720 (0.87) in 2016. For these estimates, correction of availability bias was performed using data from archival tags attached to Dall’s porpoises. Those estimates were 239 (0.96) in 2014, 1363 (0.83) in 2015, and 1281 (0.91) in 2016. Sightings of porpoises were concentrated in shallow coastal waters in 2015 and 2016, while porpoise schools tended to be distributed offshore in 2014. Cold and high-productivity waters shrank to the coastal region in 2015 and 2016, corresponding well with high-density concentration of porpoises in coastal waters in these years.

The Bornean orangutan (Pongo pygmaeus wurmbii) density in a logging concession of Hulu Belantikan, Central Kalimantan, Indonesia

Abstract. Sapari I, Perwitasari-Farajallah D, Utami Atmoko SS. 2019. The Bornean orangutan (Pongo pygmaeus wurmbii) density in a logging concession of Hulu Belantikan, Central Kalimantan, Indonesia. Biodiversitas 20: 878-883. The Bornean orangutan is currently categorized as a critically endangered species. It is found in natural forests in Borneo, where about 78% of the total population is found outside protected areas, of which 29% is in logging concessions. This study aimed to analyze the density of the orangutan population and the abundance of fruiting plants in a logging concession and Protection Forest (Hutan Lindung) in the Hulu Belantikan forests in Lamandau District, Central Kalimantan, Indonesia. Research and data collection was conducted between December 2013 to October 2014. Orangutan population density was calculated using line transect methodology based on nest counts. Abundance of fruit plants was calculated using the fruit trail method. The highest orangutan density, 4.8 individuals/km2, was found in Protection Forest; and the lowest density, 0.4 individuals/km2, was in [Sopanan] the 2013 logging block. Observations in the logging area indicated that selective logging could alter the structure and gap of the canopy and reduce the proportion of large trees. Changes in forest structure resulted in negative effects on the density of the orangutan population. The remaining degraded forests can still be a valuable resource for the orangutan. As long as the disturbance is not intensive, orangutans will retain access to the less disturbed forest nearby and to forests that are still connected to primary forests. The existence of Protection Forest and old logged-over forests around logging blocks are very important for conservation, providing refugia for orangutans and other species when logging occurs.

English

Distance sampling with line transect method has been applied by many researchers to monitor and observe varied animals and plants with the aim to estimating population density and/or abundance. The detection and detectabilities of plants and animals with line transect methodology appear to be described as seen in the application software DISTANCE by some four specific models or mathematical functions. This study has established the need for an expansion of the functional space of the application software of the distance sampling with line transect application to cater for differences in species with different biological characteristics, and revealed that the detection of plants and animals of all species of different kinds can be described differently with distinct functions, as differences in biological characteristics of different species can be manifested in their detections and detectabilities. Key words: DISTANCE, distance sampling, detectability, line transect method, Mole National Park (MNP).

The Effect of Quail Feeders on Northern Bobwhite Density in Western Oklahoma

We investigated the effect of quail feeders on northern bobwhite (Colinu s virginianus) covey size and density from I October 1991 to 1 October 1996 on the Packsaddle Wildlife Management Area (WMA ) in western Oklahoma. Thirty-two quail feeders tilled with milo were located near the center of every 8. 1 ha on a 283.3-ha treatment area. An adjacent 283.3-ha control area contained no quail feeders. Line-transect methodology was used to seasonally determine covey size and density on each area. Transects were traversed on horseback during October and March of each year. Mean fall covey size was similar (t = 0.19, df = 1, P = 0.8525) between the control (14.0 ± 1.2 birds/covey ) and treatment (14 .2 ± 1.1 birds/covey) areas, pooled over years . Mean spring covey size was similar (t = 10.18, df = 1, P = 0.9999 ) between the control (9.4 ± 1.9 birds/covey) and treatment (6.6 ± 1.5 birds/covey) areas, pooled over years . Pooled over treatments, mean covey size was similar (F = 1.30, df = 4, P = 0.2798) among years. but differed (F = 40.56, df = 1, P = 0.0001) between spring (7.6 ± 1.2 birds/covey) and fall (14.1 ± 0.8 birds/ covey). Mean bobwhite density, pooled over seasons and years was similar (t = -3.55, df = 1, P = 0.9125 ) between control ( 1.28 ± 0.43 birds/ha) and treatment (1.38 ± 0.44 birds/ha) areas. We concluded that quail feeders had no effect on mean covey size or density of bobwhite populations on our study area in western Oklahoma.

Purse-seine vessels as platforms for monitoring the population status of dolphin species in the eastern tropical Pacific Ocean

In the eastern tropical Pacific Ocean, yellowfin tuna (Thunnus albacares) are often found in association with spotted (Stenella attenuata) and spinner (Stenella longirostris) dolphins. Purse-seine vessels use this co-occurrence to locate the tuna by searching for dolphins and associated birds. Data collected by onboard observers since the late 1970s were used to develop indices of relative abundance for dolphins, based on line-transect methodology, when the primary method of detection of dolphin herds was with binoculars. However, trend estimation was subsequently discontinued in 2000 due to concerns about changes in reporting rates of dolphin herd detections with increased use of helicopter and radar search. At present, as a result of a hiatus in fishery-independent surveys since 2006, fisheries observer data are the only source of information with which to monitor the status of eastern tropical Pacific Ocean dolphin populations. In this paper, trend estimation with the onboard observer data is revisited using a sightings-per-unit-effort approach. Despite different assumptions and model structure, the results indicate a lack of independence between the distribution of search effort and the search methods used, and the abundance of dolphin herds associated with tunas, on several spatial and temporal scales. This lack of independence poses a considerable challenge to the development of a reliable index of relative abundance for dolphins with these data. Given these results, alternatives for dolphin abundance estimation are discussed. One alternative is the use of purse-seine vessels for line-transect surveys during fishery closure periods. Another alternative is the use of purse-seine vessels during normal fishing operations as platforms for the collection of mark-recapture data (e.g., passive integrated transponder tags or genetics sampling). Life-history data collection, as a supplement to the collection of other data types, is also discussed. Further research and development is needed to assess whether these alternative methods will be useful.

Welfare assessment in broiler farms: Transect walks versus individual scoring

Current scientific approaches to welfare assessment in broilers are based on individual sampling that can be time consuming under field conditions. On the other hand, farmers conduct routine checks based on walks through the house to screen birds' health condition. We adapted the walks through following line transect methodology used in wildlife studies to explore their feasibility as a welfare assessment tool. The aim of this study was to compare broiler welfare assessed by individual sampling and transect walks. We evaluated 6 identically managed flocks. For individual sampling, we collected measures on 150 birds, including weight, breast dirtiness, hock and footpad dermatitis, lameness, and immobility. Transect observations were conducted by slowly walking on randomized paths within each house recording: immobility, lameness, back dirtiness, sickness, agony, and dead. Transect walks allowed detection of small variations (P < 0.003) in the prevalence of most welfare indicators considered with consistency in interobserver reliability (P ≥ 0.05). In addition, assessments across transects were highly consistent (P ≥ 0.05). Individual sampling was also sensitive to differences across houses (P < 0.01) with the exception of immobility (P = 0.783). No differences were found across sampling locations (P ≥ 0.05). However, both methods differed greatly in the frequency of the incidence of the parameters considered. For example, immobility varied from 0.2 ± 0.02% for transect walks to 4 ± 2.3% for individual sampling, whereas lameness varied between 0.8 ± 0.07% and 24.2 ± 4.7% for transect and samplings, respectively. It is possible that the transect approach may have overlooked walking deficiencies because a large number of birds were scored, although if this was the case, the consistency obtained in the scoring across observers and transects would be surprising. Differences may also be related to possibly biased individual sampling procedures, where less mobile and passive individuals may be more likely to be caught. Furthermore the procedure may cause fatigue and fear reactions reducing mobility. Current study provides new insights into constraints and advantages of broiler on-farm assessment methods, which should be considered for designing on-farm welfare assessment protocols.

Presión de caza sobre crácidos (Cracidae: Aves) en concesiones forestales en Perú

The impact of timber exploitation on biodiversity is usually increased by hunting in the exploited area. Proper forest management practices on areas under commercial exploitation minimize hunting and damage to the forest. Large species of Cracidae, the most endangered family of birds in the Neotropics, are among the first to be affected in a Neotropical forest damaged by timber-extraction activities, and where at least moderate hunting occurs. Herein an assessment of cracids is carried out in three areas with selective logging in Peru in 2004 and 2005, is used to evaluate hunting pressure. Tree inventory trails were used as transects, and density was calculated using the line transect methodology. Four species of cracids were evaluated, and density was calculated for three of them. The area with lower hunting pressure, Maderyja, showed higher cracid diversity and was the only with the presence of razor-billed curassows (Mitu tuberosum) and blue-throated pining-guans (Pipile cumanensis), two sought-after prey species. Areas where hunting intensity is higher had lower cracid diversity. The density of the M. tuberosum was high in Maderyja: 11.3 ind/km2 (95% CI: 7.4 – 17.3 ind/km2). In contrast, Spix’s guan (Penelope jacquacu) did not show a marked difference among areas, unless compared to heavily hunted sites. The higher diversity of cracids and the density found for razor-billed curassows suggests Maderyja had low hunting pressure in the past and is properly managed towards wildlife. Currently, the Peruvian Amazon is being opened for forestry concessions and hydrocarbons exploitation and proper management towards wildlife is necessary to guarantee the conservation of susceptible taxa such as cracids.

Population Density Estimates of the Critically Endangered Yellow-tailed Woolly Monkeys (Oreonax flavicauda) at La Esperanza, Northeastern Peru

The critically endangered yellow tailed woolly monkeys (Oreonax flavicauda, Humboldt 1812) are endemic to the cloud forests of northeastern Peru. We surveyed populations of Oreonax flavicauda in the Centro Poblado La Esperanza, Amazonas department between May 2008 and March 2009. We conducted census work in an area comprising disturbed primary cloud forest interspersed with pasture lying between 3 protected areas, all of which are known to contain populations of Oreonax flavicauda. We used standardized line transect methodology to census an area of ca. 700 ha. We also recorded group size and composition. We compared the results of transect width estimation, Krebs’ method, and an ad libitum total group count. We calculated individual densities of 8.27/km2 and 9.26/km², and group densities of 0.93/km2 and 1.04/km² using Krebs’ method and transect width estimation, respectively. Average group size was 8.9, with 1–3 adult males, 1–6 adult females, and 0–6 juveniles and infants. The results from our transect surveys coincided well with our estimated total group count. Our results are similar to those from previous studies, although differences in methodologies and site-specific environmental factors make comparison difficult, and suggest that Oreonax flavicauda is able to survive in disturbed habitat when hunting pressure is low.

Patterns of diversity, abundance and habitat associations of butterfly communities in heterogeneous landscapes of the department of atomic energy (DAE) campus at Kalpakkam, South India

The diversity of butterflies inhabiting the department of atomic energy campus at Kalpakkam was recorded through a modified line transect methodology by setting a permanent line transect of 300 m and recoding all species of butterflies observed within a five meter distance around the observer. Five habitats within the campus viz., Garden, Scrub jungle, Riparian woods, Sandy area and Casuarina plantation (Monoculture) were evaluated for analysis of the association of the butterfly species with the habitat. A total of 1908 individuals representing 55 species were observed across the five habitat types. Out of these, members belonging to the family Nymphalidae was the most common with 20 species being recorded accounting for 36.3% of total species and 53.6% of total number of individuals collected. The maximum diversity and abundance was observed in the scrub jungle and garden area; these two habitats sharing 29 species among themselves. The species accumulation curve and rarefaction curves computed indicated the likelihood of encountering more number of species in the campus had inventory been more rigorous and extended. The butterfly species viz.,Danaus chrysippus, Castalius rosimon, Tirumala septentrionis, Ariadne merione, Appears libythea and Cepora nerissa preferred scrub jungle and garden habitats than the other habitats. The species profile of butterfly communities associated with different habitat and the importance of avian predation in the campus were also discussed in detail. Key words: Butterfly, species composition, habitat association, DAE campus.

Density and Population Estimation of the Bornean Elephants (Elephas maximus borneensis) in Sabah

Problem statement: In Asia, four elephant subspecies have been identified, Elephas maximus maximus from Sri Lanka, Elephas maximus summatranus from Sumatra, Elephas maximus borneensis (based on recent DNA analysis) from Borneo and Elephas maximus indicus, from mainland Asia. The Bornean elephant has a limited distribution and is found only in the northeastern part of the island, (Malaysian Sabah and Indonesian Kalimantan). Previous estimations for the population in Sabah have ranged between 500-2000 elephants. These estimations have been carried out through a non-systematic approach, either via interview or from direct sightings or extrapolating population count data from limited sites. In order to prepare the conservation plan for this species in Sabah, there is a need to establish reliable information on their density and population size. The main objective of this study was to determine the elephant density and population size in five main elephant managed ranges in Sabah. Approach: In this study, relative distribution and spatial density of the Bornean elephant was developed and established, using a systematic line transect survey and a long term monitoring of dung decay rates. We conducted the elephant population census in Sabah between July 2007 and December 2008. Using a line-transect dung-count methodology, we surveyed 216 line transects; with a total distance of 186.12 km, in five main elephant managed ranges. Namely (i) Tabin Wildlife Reserve, (ii) Lower Kinabatangan, (iii) Central Forest, (iv) North Kinabatangan and (v) Ulu Kalumpang. Results: We presented the elephant density estimate using long term monitoring of dung decay rates. In each range, the elephant’s density varied depending on the size of the suitable habitat. The size of the suitable habitat was derived from WWF’s study report (WWF-Malaysia, 2008). Densities were analyzed following line-transect analysis guidelines and were computed using the software Distance v6.0. Conclusion: Our survey indicated that approximately 2,040 (95% CI: 1,184-3,652) elephants remain in the five main ranges in Sabah, with the largest population being in the unprotected central forests. Elephant density was highest in ranges where habitat has been removed and elephants are concentrated in remaining forest areas. These results provide new baseline data for the elephant population in Sabah.

A note on the distribution and abundance of blue whales (&lt;i&gt;Balaenoptera musculus&lt;/i&gt;) in the Central and Northeast North Atlantic

The distribution and abundance of blue whales (Balaenoptera musculus) was assessed from ship surveys conducted in the Central and Northeast Atlantic in 1987, 1989, 1995 and 2001. Blue whales were most commonly sighted off western Iceland, and to a lesser extent northeast of Iceland. They were very rare or absent in the Northeast Atlantic. Sightings were combined over all surveys to estimate the detection function using standard line transect methodology, with the addition of a covariate to account for differences between surveys. Total abundance was highest in 1995 (979, 95% CI 137-2,542) and lowest in 1987 (222, 95% CI 115-440). Uncertainty in species identity had little effect on estimates of abundance. There was a significant positive trend in abundance northeast of Iceland and in the total survey area.