1,720,983 research outputs found
Comparative Assessment of Amphibian Abnormalities Associated with the Lentic Water Bodies of Montane Forests
Get PDFAmphibian abnormalities are good ecological screening tool to assess the ecosystem health. Abnormalities are governed by both biotic and abiotic factors. Since most of the worldwide abnormality studies have been focused on laboratory studies rather than field surveys, the actual threat of amphibians can’t be determined. Amphibian abnormalities were studied in three lentic water bodies of Horton Plains National Park (HPNP) and two lentic bodies outside the park (OHPNP) from January 2017 to November 2017 for three consecutive days per month. Abnormalities were identified through gross visual inspections, utilizing six quadrates of 1×2 m in each sampling site with the purpose of providing precise information to support conservation and management of amphibians. A total of 694 amphibians belonging to 4 families and 11 species were recorded during the study in the five lentic water bodies studied. 511 individuals were examined inside the HPNP and 183 individuals were examined outside the HPNP. Out of the 183 individuals examined outside the HPNP, 148 (81%) had abnormalities. Of the 511 amphibians within the HPNP, 0.59% suffered from ectromelia and 3.91% had cysts. Of the 183 amphibians examined outside the HPNP, 80.33% had cysts and 0.55% had femoral projections. Cysts accounted for most of the abnormalities in both environments. Most of the abnormalities were observed in hind limbs of amphibians in both locality types. Inside the HPNP hindlimb abnormalities accounted for 91.3% and OHPNP they accounted for 100% of the abnormalities. Forelimb abnormalities were recorded only inside the HPNP. These accounted for 8.7% of the abnormalities. Abnormalities in the abdominal region accounted for 4.35% of abnormalities. 100% of the endangered amphibians found OHPNP had abnormalities. Inside the HPNP only 4.55% of the endangered amphibians had abnormalities. 3.57% of amphibians categorized under the least concerned status had abnormalities. Extensive further studies are warranted to find out the reasons for these abnormalities observed.Keywords: Abnormalities, Amphibians, Horton Plains National Par
Breeding Biology of Dull-blue Flycatcher (Eumyias sordidus) in Tropical Montane Cloud Forests of Sri Lanka
Get PDFBreeding biology of Dull-blue flycatcher (Eumyias sordidus) was studied in tropical montane cloud forests of Horton Plains National Park. The study was conducted from March 2016 to December 2018 during the breeding season and each visit five to ten days observations were made. Nests were searched using pole and mirror method. Binocular (NikonTM-Monarch, 10×42) was used to study bird behaviours. Incubation patterns such as on-bout and off-bout duration, nest trips rate and nest attentiveness were studied. Nestling diet was observed using a spotting scope (Nikon MonarchTM, 20-60×82 ED), hidden camera (SJCAM, M20) and faecal sample analysis. Total of 32 breeding pairs were observed during the study period. They laid a single egg 2 to 3 days after completing the nest construction, and another egg was laid within 24 hrs. The mean clutch size was 2±0.54 eggs (n=32), mean egg mass was 2.51±0.04 g (n=15), mean egg length was 21.29±0.32 mm (n=15) and mean egg width was 15.20±0.39 mm (n=15). The average incubation period was 20.1±2.2 days (n=16) and the average nestling period was 14±3.1 days (n=15). During the incubation period, onbout duration (18.38±6.38 min) and nest attentiveness (78.02±7.51%) was higher in the evening period. Off-bout duration (36.54±6.52 min) was higher in the dawn period. Nest trips rate (6.02±0.67 h-1 ) was higher in the mid-day. During the nestling period, on-bout duration (4.13±2.08 min) and nest attentiveness (70.83±12.42%) was higher in the morning period. Off-bout duration (3.56±1.42 min) and feeding trips rate (9.47±1.19 h-1 ) was higher during the mid-day. They have selected ten Orders of invertebrates, one amphibian and two plant species to feed their nestlings. Both sexes participated in incubation and brood rearing. E. sordidus were monogamous and singlebrooded although some pairs made re-nesting attempts after first nests failed. The overall nest success was 90.62%. Jungle crows were the main nest predators of E. sordidus. Therefore, control measures need to be conducted to minimise the disturbances to warrant the protection of future generations of E. sordidus.Keywords: Breeding biology, Conservation, Tropical Montane Cloud Forests, Eumyias sordidu
Habitat Utilization and Behavioral Patterns of the Endemic Sri Lankan Green Pit Viper (Craspedocephalus trigonocephalus) in the Wet Zone of Sri Lanka
Get PDFBehavioral patterns and habitat utilization of the endemic Green Pit Viper (GPV) Craspedocephalus trigonocephalus were studied in the wet zone of Sri Lanka. The region, which is covered by the wet zone, has no significant dry periods and a moderately high mean annual rainfall of over 2,500 mm. Data collection occurred between April 2021 and March 2022 with a total of 260 hours of standardized sampling effort distributed throughout the collection period. The method used was an active search which consists of a visual search of up to six meters from the central line along each side of the quadrate. Quadrats were placed in habitats, taking each GPV sighting as the center of a quadrate. At each GPV-occupied quadrat, ambient temperature, body surface temperature, prey availability, perch position and perch light level were recorded. The day was divided into six-time periods as; early morning, morning, mid-day, evening, late evening, and night. Activity level was determined considering the number of GPV that could be visually observed. A total of 49 GPV were examined during the study. Focal animal sampling was conducted, and an ethogram was developed. A strong positive relationship was observed between ambient temperature (Ta) and body surface temperature (Ts) of GPVs (Pearson correlation r=0.936). The highest number of individuals preferred filtered sun light (57.14%). C. trigonocephalus mostly preferred distal position on the branches followed by middle and apical. There was a significant difference in the percentage of individuals with different behaviors [ANOVA, F=3.64, p<0.05]. Behavioral pattern of GPV varied in the temporal scale during the day. During the morning time slot, C. trigonocephalus spent most of the time ambushing (16.12%) and basking (6.42%) respectively. During the mid-day they spent most of their time basking (10.57%), followed by resting (7.15%). The evening, late evening, night, and early morning slots were spent mostly on ambushing. The highest average time of 239 min was spent on ambushing behavior. Feeding behavior (9.8 min) had relatively short time on average. Results of this study indicate that C. trigonocephalus is well adapted for the utilization of its preferred habitat in the wet zone, and that, it displayed behavioral patterns that vary within temporal scales, which results in more efficient and effective utilization of resources. Therefore, this study provides important insights for conservation and management of C. trigonocephalus by critically evaluating the requirements of this species.
Keywords: Craspedocephalus trigonocephalus, Behavior, Endemic pit viper, Wet zone 
Structure of Mixed Species Bird Flocks in Montane Forest Habitats of Horton Plains National Park
Get PDFMixed species bird flocks (MSBFs) are distributed worldwide and can be reached their maximum diversity in temperate forests during the non-breeding season and in tropical rainforests year round. The structure of MSBFs can be explained using vertical and horizontal distribution of flocks. MSBFs were observed in the tropical montane cloud forest habitats of Horton Plains National Park (HPNP) from December 2017 to October 2018. As soon as a mixed species flock was met, the vegetation was scanned thoroughly from the canopy layer down to the forest understory to identify the vertical structure of all flock participants. Height which each participant occupied was visually estimated. Horizontal distribution was determined by standing at a fixed point, and recording the order in which each species appeared and disappeared as the flock went past the observation point. The Crossing score values were calculated. Scarlet Minivet utilised the highest canopy height and Sri Lanka Bush Warbler utilised the lowest canopy height. Great Tit occupied a higher range of canopy height than other species. There were nine species who led the MSBFs. Sri Lanka Orange-billed Babbler was the most specific leading species and Scarlet Minivet was in the second place. Sri Lanka Yellow-eared Bulbul had the least possibility to lead a flock. Great Tit, Grey-headed Canary Flycatcher, Sri Lanka White-eye and Sri Lanka Scimitar Babbler had higher chance to lead MSBFs because Sri Lanka Orange-billed Babbler and Scarlet Minivet were not common in MSBFs and they were not frequent flocking species. Sri Lanka Orange-billed Babbler had the least crossing score value (0.18±0.15) and Sri Lanka Bush Warbler had the highest crossing score value (0.89±0.12). Sri Lanka White-eye, Great Tit, Sri Lanka Scimitar Babbler and Velvet-fronted Nuthatch utilised a wide range of crossing score values in the MSBFs. The vertical and horizontal structure of the MSBFs indicates the niche partition between the flocking species. Findings of this study can be utilised for the conservation measures within these habitats.Keywords: Mixed species bird flocks, Vertical structure, Horizontal structure, Crossing scor
Influence of Recreational Trails on Tertrapod Vertebrates within the Horton Plains National Park
Get PDFInfluence of recreational trailson tetrapod vertebrates was studied within Horton Plains National Park (HPNP) for a period of one year from December 2017 to November 2018. In order to study quantification of visitor disturbance, three main habitats were identified as cloud forest, aquatic habitats and grasslands. Hundred-meter fixed length line transects were marked along the recreational trails in three selected habitat types. Disturbances were quantified under the categories; road kills, photography, animal feeding, trampling, visitor noise level. Visitor noise were measured using sound meter software (mobile app). Road kills were recorded while walking in transects. Visitor activities were recorded, including photography, trampling and animal feeding under number of disturbances. Amphibians and reptiles road kills were higher compared to other tetrapod road kills during vacation periods. Photography and animal feeding were highly recorded in aquatic habitat. Highest average percentage of disturbances were occurred by trampling in the grasslands of recreational trails. Behavioral response of species to visitor disturbances included avoidance, habituation and attraction. When the visitor noise was between (42±1.75) dB to (57±1.75) dB habituation behavior was displayed. When visitor noise range was in the range of (58±2.88) dB to (83±2.88) dB avoidance behavior was displayed. Results of the present study indicate that visitor disturbance interfered to disturb the tetrapod vertebrates within HPNP. Therefore, visitor activities are interfering the natural behavior of tetrapod vertebrates within HPNP. Therefore, it is advisable to educate the visitors to be vigilant when traversing the recreational trails. Awareness posters should be displayed regarding of reducing noise level and prohibition of trampling in the recreational trails. The results of this study can be used to integrate with the future visitor and park management practices.Keywords: Visitor disturbance, HPNP, Behavioral response, Tertrapod vertebrate
Investigating the Assemblage and Activity Patterns of Mesomammals of Order: Canivora in Maduru Oya National Park Using Camera Trap
Get PDFMesomammals of Order: Canivora represent an influential guild of forest vertebrates in the dry zone forests of Sri Lanka. This study was conducted to investigate the carnivorous mesomammal species assemblage and activity patterns in Maduru Oya National Park (MONP). Camera traps are increasingly used to study species activity patterns and temporal overlap among sympatric species as well as other heterospecific groups. In this study, camera trap surveys were conducted from January 2019 to May 2020 using 47 camera stations with a cumulative sampling effort of 1,410 trap days. Camera station locations were spatially arranged in a semi-random approach and camera locations were changed after operating 24 hours for a period of<30 days to increase the spatial coverage. Camera traps were stationed to represent all the habitat types present in MONP. Time stamp data on captured photos/videos were used to analyse mesomammal activity patterns. Nine of the 12 mesomammal carnivores present in the country were recorded in MONP. With a capture frequency of 184 and a recording rate of 13.05 (per 100 camera-trap days) Ruddy mongoose (Herpestes smithii) was the most abundant species recorded followed by Ring-tailed civet (Viverricula indica). Eurasian otter (Lutra lutra) and Rusty-spotted Cat (Prionailurus rubiginosus) were the rarest species with a recording rate of 0.14. Based on the activity pattern analysis, Sri Lankan Jackal (Canis aureus naria) and all mongoose species displayed diurnal activity patterns. Golden palm civet (Paradoxurus zeylonensis) and Ring-tailed civet were highly nocturnal. Fishing cat (Prionailurus viverrinus) with a relatively high recording rate of 4.33 was observed to be displaying some plasticity in its activity patterns being active in both nocturnal and diurnal hours. It would reduce overlapping of activity with other species such as Ring-tailed civet. The study reveals the coexistence of mesomammal carnivores in MONP and the temporal variation in activity patterns of different carnivore species. MONP can be identified as an important protected area for the mesomammal carnivores of the island due to the availability of suitable habitats to provide habitation to a considerable amount of species present in the county.
Keywords: Activity patterns, Dry zone, Camera trapping, Species abundance, Species co-occurrenc
Distribution, Abundance, Activity Patterns and Habitat Characteristics Associated with Family Herpestidae (Mammalia: Carnivora) in Three Protected Areas Representing Three Main Bioclimatic Regions of Sri Lanka
Get PDFFour species of mongooses; Brown mongoose (Herpestes fuscus), Grey mongoose (H. edwardsii), Black-tipped/Ruddy mongoose (H. smithii) and Stripe-necked/Badger mongoose (H. vitticollis) belonging to the family Herpestidae are found in Sri Lanka. The distribution, abundance, activity and habitat characteristics of family Herpestidae was studied using camera traps in three protected areas (Horton Plains National Park-HPNP, MaduruOya National Park-MONP and Sinharaja Forest Reserve-SFR) that represent three of the six main bioclimatic regions of the island. Ruddy mongoose had the highest trap success (9.58, a measure of relative abundance) at MONP which was also the highest among all the species considered for any given study site. Interestingly, Stripe-necked mongoose was the most abundant in SFR with a trap success of 2.95. At each study site, there was a prominent species with a higher trap success followed by the remaining species with lower trap success rates. With a total of 143 mongoose sightings, MONP can be considered to be providing the suitable habitats for these animals with optimum conditions when compared to HPNP and SFR. Ruddy mongoose preferred habitats with higher rock availability while Stripe-necked mongoose preferred aquatic habitats. High leaf litter cover, litter depth and forested habitats with canopy cover were identified as important habitat characteristics that are associated with three observed Herpestids at MONP. Grey mongoose was absent in all camera trap records which suggests that habitat requirements of this species are not met within the study sites of focus. Data generated through this study can be incorporated for effective conservation and management measures in the future.KEYWORDS:Camera trapping, Mongooses, Meso-mammals, Relative abundance, Bioclimatic zone
Diversity and Distribution of Avifauna at the Tropical Montane Cloud Forests of Horton Plains National Park
Get PDFDiversity and distribution of avifauna was studied at the tropical montane cloud forests of Horton Plains National Park, situated in the highland plateau of the Nuwara Eliya district from September 2015 to May 2016. Three main habitats were identified; cloud forest habitat, cloud forest die-back habitat and grassland habitat. Nine, 300 m line transects were marked in each of the habitats. Avifauna was recorded on three consecutive days of each month while travelling along these transects. Seventy eight species of birds were recorded during the study period. This included 66 resident species (with 13 endemic species) and 12 migratory species. The maximum value of the Shannon Wiener Index H' of 2.56 was recorded from the cloud forest habitat. In the cloud forest die-back habitat the H' was 2.49 and in the grassland habitat the H' was 2.31.The Jaccard similarity index, between cloud forest and cloud forest die-back was 0.58, and these two habitats had more common species. Cloud forest is the major habitat to be protected, with other habitats, in HPNP. Hence management of the HPNP should plan more actions to improve long term monitoring plans to warrant the protection of threatened species.Keywords: bird diversity and distribution, endemic birds, Horton Plains, tropical montane cloud fores
Microhabitat Utilisation of Endemic Lizard Calotes nigrilabris in the Grasslands of Horton Plains National Park, Sri Lanka
Get PDFThe endemic endangered agamid lizard Calotes nigrilabris inhabits the grasslands of Horton Plains National Park (HPNP) and it is restricted to a few localities in the central highlands of Sri Lanka. In this study, the microhabitat utilisation of Calotes nigrilabris was investigated utilising line transects and quadrate method. The comparison of available microhabitat variables with occupied microhabitat variables revealed that there was a significant difference between some of the variables (Man-Whiteney U test, p<0.05) indicating that C. nigrilabris was selective in its microhabitat utilisation. Based on PCA analysis, amount and type of vegetation was the main determining factor of microhabitat preference of this species. Ulex sp. cover (PC1, 0.606) and Rhododendron sp. cover (PC2,-0.603) were significantly affecting the occupied microhabitat structure. Microhabitat utilisation varied in the temporal and spatial scales also indicating clear resource partitioning between different maturity stages. The results of this study indicate that C. nigrilabris actively selects and utilises the most suitable grassland microhabitats of HPNP and provide important insights for the conservation and management of the species as well as its natural habitat
Spatial Resource Partitioning Exhibited by Endemic Agamid Species within Selected Forest Habitats of Sinharaja Forest Reserve
No full textOver the years, lizard ecologists have placed importance on the study of habitat occupancy among agamid species by investigating resource partitioning and interspecific competition within selected habitats. Lizards sharing resources has been proposed as a driving factor for species coexistence and diversity within an ecological niche. Species mainly partition resources in three niche dimensions, namely, food (foraging), time (temporal) and space (microhabitat). The present study was aimed at determining the microhabitat utilization and spatial resource partitioning exhibited by four endemic agamid species namely, Cerataphora aspera, Calotes liolepis, Lyriocephalus scutatus and Otocryptis weigmanni within the unlogged and selectively logged forest habitats of Sinharaja Forest Reserve (SFR). Visual encounter survey and random quadrat sampling methods were used traversing 200 m transects and quadrats of 1×1 m2 area during the study period from January 2020 to March 2021 spending 410 person-hours in the field, to determine the spatial resource partitioning of the species along three microhabitat variables: perch height, perch diameter and leaf litter depth. The spatial niche breadth for each agamid species was computed using the Shannon-Wiener measure of niche breadth (J’) and Pianka index was used to determine the spatial niche overlap among the agamid species. Accordingly, the study revealed mean J’ values narrower than 1.5 for all agamid species concerned, concluding them to become forest habitat specialists along the spatial resource dimension. Mean J’ value of L. scutatus was high (0.74) in comparison to O. weigmanni (0.40), C. liolepis (0.37) and C. aspera (0.08). Furthermore, the Pianka index for niche overlap between the species indicated the highest spatial niche overlap between C. liolepis and L. scutatus (0.552) followed by spatial niche overlap shown between C. aspera and C. liolepis (0.550) and between L. scutatus and O. weigmanni(0.509). Field observations further showed that amidst the existing spatial resource competition, the species ensure coexistence via other resource dimensions. Habitat specialists are considered more susceptible to threats from habitat degradation and human influences compared to generalists. It is necessary to quantify the degree of overlap in the use of resources for the purpose of providing a biological and statistical meaning to determine when and where resources are used disproportionately to their availability and thereafter, enact timely conservation actions to ensure optimum resources to support fitness of the species. Hence, the results of the present study can be implied to support species conservation and in turn aid in better management of the natural world heritage site of SFR.
Keywords: Agamid, Sinharaja forest reserve, Microhabitat, Niche overlap, Conservation and managemen
- …
