Line Transect Method Research Articles

How to Count Parrots: Comparing the Performance of Point and Transect Counts for Surveying Tasman Parakeets (Cyanoramphus cookii)

Obtaining precise estimates of population size and trends through time is important for the effective management and conservation of threatened species. For parrots (Psittaciformes: Psittacidae), obtaining such estimates can be challenging, particularly for cryptic species that occur in low densities in complex and/or fragmented habitats. We used a statistical resampling approach with the aim to compare the reliability and precision of counts for the critically endangered Tasman parakeet (Cyanoramphus cookii) that were taken using two methods on Norfolk Island (Pacific Ocean), namely, fixed-point counts and line transect counts. The detections obtained during fixed-point counts had better estimated precision (0.274) than line transect counts (0.476). The fixed-point method was also more efficient, yielding 1.338 parakeet detections per count compared to the 0.642 parakeet detections per count obtained by the line transect method. Although Tasman parakeets can be detected by either of these methods, our research demonstrates that the fixed-point method is more precise and reliable. These findings can help prioritise resources for the long-term monitoring of recovering populations of this species and similar island species.

Effects of human disturbance on the distribution and abundance of large mammals in Abijata-Shalla Lakes National Park, Ethiopia

The increasing human pressure has threatened wildlife conservation, even in protected areas. However, findings reporting the effects of human on wildlife conservation are not consistent. This study aimed to investigate the effect of human disturbance on the distribution and abundance of mammals in Abijata-Shalla Lakes National Park considering the consumptive and non-consumptive modes of human activities. The study was conducted from September 2017 to February 2018 in three selected sites, which were stratified based on human disturbance as nature conserved areas, sites engaged in consumptive livelihood, and ecotourism sites. Data were collected using a line transect method. The distribution and abundance data were analyzed using Chi-square tests and one-way ANOVA, respectively. There was a significant difference on the distribution of target wild animals in the selected sites; greater kudu (P < 0.001), warthog (P < 0.01), and bohor reedbuck (P = 0.03) were highest in the “nature conserved” site. Human disturbance also significantly affected the abundance of warthog (P = 0.028), greater kudu (P < 0.001), and bohor reedbuck (P = 0.024). Greater kudu distribution was limited in nature conserved site. However, Warthog and Bohor Reedbuck were distributed in all sampling sites; nature conserved sites hold the highest population abundance. The results indicate that consumptive local livelihood and ecotourism disturbances adversely affected the distribution and abundance of mammals relative to the nature reserved site. However, ecotourism favored some mammal species from the consumptive local people’s livelihood activities. Thus, to reduce the impact of human disturbances on wildlife conservation, monitoring and controlling the level of human disturbance is urgent. Sustainable practices such as community engagement, awareness creation and alternative livelihood options should be proposed.

KERAGAMAN JENIS BURUNG DI KAWASAN PENGAMATAN BURUNG BIDADARI KALI BATU PUTIH, HALMAHERA BARAT, MALUKU UTARA

Kali Batu Putih ‘Standardwing Bird of Paradise Observation Area’ is located in West Halmahera, North Maluku. The forest in this area is a habitat for various species of birds, such as the Standardwing Bird of Paradise which is the icon of this location. This research was conducted with the aim of analyzing the diversity of bird species in the Kali Batu Putih ‘Standardwing Bird of Paradise Observation Area’. Bird species observations were carried out using a combination of line transect and point count methods. Bird species data collection was also carried out using the MacKinnon species list method. The forest conditions at the research location are secondary lowland forests at an altitude of 100-200 m asl. A total of 32 species of birds from 22 families were found in the research location. The Psittacidae family, the parrot group, has the largest number of species. Based on the feeding guild, insectivorous and frugivorous species are more dominant. There are three bird species categorized as near threatened on the IUCN red list and 11 species are protected by law in Indonesia. The number of endemic bird species is quite abundant, as many as 14 species or 44% of all species found. The large number of endangered, protected, and endemic bird species needs to be a concern by area managers in increasing bird conservation efforts in the Kali Batu Putih area. Conservation steps can be taken through habitat management activities, periodic monitoring, increasing biodiversity research, and developing ecotourism governance by involving communities around the forest.

Maize crop residue cover mapping using Sentinel-2 MSI data and random forest algorithms

The return of crop residues to cultivated fields has numerous agronomic and soil quality benefits and, therefore, the areal extent of crop residue cover (CRC) could provide a rapid measure of the sustainability of agricultural production systems in a region. Recognizing the limitations of traditional CRC methods, a new method is proposed for estimating the spatial and temporal distribution of maize residue cover (MRC) in the Jilin Province, NE China. The method used random forest (RF) algorithms, 13 tillage indices and 9 textural feature indicators derived from Sentinel-2 data. The tillage indices with the best predictive performance were STI and NDTI (R2 of 0.85 and 0.84, respectively). Among the texture features, the best-fitting was Band8AMean-5*5 (R2 of 0.56 and 0.54 for the line-transect and photographic methods, respectively). Based on MSE and InNodePurity, the optimal combination of RF algorithm for the line-transect method was STI, NDTI, NDI7, NDRI5, SRNDI, NDRI6, NDRI7 and Band3Mean-3*3. Likewise, the optimal combination of RF algorithm for the photographic method was STI, NDTI, NDI7, SRNDI, NDRI6, NDRI5, NDRI9 and Band3Mean-3*3. Regional distribution of MRC in the Jilin Province, estimated using the RF prediction model, was higher in the central and southeast sections than in the northwest. That distribution was in line with the spatial heterogeneity of maize yield in the region. These findings showed that the RF algorithm can be used to map regional MRC and, therefore, represents a useful tool for monitoring regional-scale adoption of conservation agricultural practices.

Assessment of mangrove structures and biomass on islands along the Java Sea: a case study on Bawean Islands and Karimunjawa Islands

Mangroves on the islands along the Java Sea play a crucial role in supporting biodiversity, protecting coastlines, and sequestering carbon. However, there is a lack of information on mangrove structure and biomass in the area. This study aimed to assess the mangrove structures and biomass on Desa Daun, located on the Bawean Islands, and Kemujan Island, located on the Karimunjawa Islands, respectively. The study utilized a combination of line transect and quadrant plot methods with a size plot of 10x10 m. We established 7 line transects and 28 quadrant plots in the mangrove forest of Desa Daun and similarly set up 7 line transects and 21 quadrant plots on Kemujan Island. Within each quadrant, the mangrove species were identified, and their diameters at breast height (DBH) were recorded. To assess the relative significance of each species, the importance value index (IVI) was calculated, and allometric equations were applied to estimate biomass and carbon storage in the trees. PlanetScope imagery was also used to quantify the carbon stock of mangroves on those islands. In Desa Daun, 13 mangrove species were identified, while 12 species were recorded on Kemujan Island. The species Nypa fruticans and Excoecaria agallocha exhibited the highest IVI in Desa Daun and Kemujan Island, respectively. Notably, Rhizophora apiculata demonstrated the greatest biomass in both locations, with measurements of 43.08 Mg B/ha in Desa Daun and 102.22 Mg B/ha in Kemujan Island. Overall, mangrove stands on Desa Daun stored biomass of 113.60 Mg B/ha and carbon of 50.98 Mg C/ha, whereas mangrove stands on Kemujan Island stored biomass of 295.04 Mg B/ha and carbon of 131.95 Mg C/ha. Mangrove stands of the whole Bawean Islands sequestered 22,941 Mg C, while Karimunjawa Islands hold much higher C stocks, 79,451 Mg C. Despite being smaller in size, the Karimunjawa Islands have more extensive mangrove coverage compared to the Bawean Islands due to their geomorphological characteristics, which in turn influence their mangrove structures and carbon stocks. However, the loss of mangroves in the Karimunjawa Islands due to aquaculture expansions could increase carbon loss in the islands.

Insights into Population Status and Habitat Patches of Conservation Concern for the Endangered Indian Pangolin (Manis crassicaudata) in Nowshera District, Northwestern Pakistan.

The Indian pangolin (Manis crassicaudata) stands out among the four surviving species of Asian pangolins, being the sole species present in Pakistan and listed as endangered owing to trafficking and illicit commerce. In the present study, we explored the population status of the Indian pangolin and the existing suitable habitats in Nowshera district, Pakistan. We employed the line transect method to confirm the species presence and subsequent population estimation. In a survey effort of 156 km2, a total of 56 signs of Indian pangolin were recorded within the research area. Amongst the 56 signs, 46 were burrows (living burrows (53.57%) and feeding burrows (28.57%)). Digging was observed nine (16.07%) times, along with one direct sighting (1.7%). Our results revealed a population estimate of only 29 pangolins in the Nowshera district, with a population density of 0.013 individuals/km2. Later, MaxEnt was applied to the species' presence points, along with climatic and topographical variables. The MaxEnt model accuracy was good (AUC = 0.811). Of the total area studied, 210 km2 (12.01%) were highly suitable and 238 km2 (13.61%) were moderately suitable habitat for the Indian pangolin. To safeguard the fragile population and habitat of the Indian pangolin, we highly suggest strengthening watch and ward and law enforcement in the study area. By adopting a comprehensive approach that addresses both the direct threats to Indian pangolins and the underlying factors driving their decline, we can effectively protect this endangered species and ensure the preservation of its essential habitats for robust conservation.

Seasonal variations in the structure of avian community in Zambezi riparian forest

Among the different biomes in southern Africa, tropical riparian forests appear to be especially rich in terms of biodiversity, but little is known about avian communities occupying these forests. In this paper, bird counts were conducted in May, July–August, and October–November in 2013 and 2014. The line transect method was used. A transect 16.6 km long was designed along the Zambezi River between S 17.4975 E 24.3478 and S 17.4874 E 24.447. In total, 146 bird species were recorded. The number of species detected each season varied from 95 to 100. The number of dominant species was consistently low, varying between 2 and 3 depending on the month. However, the cumulative dominance and the dominance index were much higher in the dry season (May–August) than in the wet season (October–November). Two species were dominant each month: Euplectes axillaris and Pycnonotus tricolor. Vidua macroura and Estrilda astrild were dominant only in October, while Streptopelia capicola was dominant only in May. The group of subdominants was much more diverse than dominants and included 13 species. The Shannon diversity index increased between July and November from 3.45 to 4.05 but Simpson's diversity index did not show any seasonal trend. Pielou's evenness index was higher in the wet season (0.82–0.88) than in the dry season (0.76–0.79). The proportions of the main feeding guilds were much the same throughout the year, except for November, when the proportion of insectivores markedly increased, while that of granivores decreased. Riparian forest corridors in urbanized environments may be viewed as main instruments for offsetting the negative effects of habitat loss and fragmentation. Dataset published through GBIF (DOI: 10.15470/0ssr1v)

Estimating the Inbreeding Rate in Natural Populations of The Black-Naped Fruit Dove (Ptilinopus melanasphila)

This research aimed to determine the population of the Black-Naped Fruit Dove (Ptilinopus melanasphila) by estimating population size, sex ratio, effective population, and inbreeding rate, providing a basis for ex-situ design considerations. Data collection employed survey techniques such as the line transect and concentration count point methods. Data analysis focused on determining population size, sex ratio, effective population, and inbreeding rate. The research was conducted in the Sula Islands, North Maluku. Observations and discussions were conducted separately for each location to obtain empirical and comprehensive data serving as a reference for further research. Results revealed the inbreeding rates at the research locations were observed as follows: Soamole village (1.42%), Wai Ipa village (1.56%), and Bega village (1.60%). Sex ratios were observed as follows: Soamole village (male : female ratio of 22.17 : 85.38), Wai Ipa village (male : female ratio of 19.48 : 73.78), and Bega village (male : female ratio of 19.61:80.39). Effective populations were observed as follows: Soamole village (22.39 heads), Wai Ipa village (16.48 heads), and Bega village (16.08 heads). The inbreeding rate is in the good category, while the population number, sex ratio and effective population are in the medium category, however habitat destruction and continuous excessive hunting can result in decline and extinction.

Suitable Habitat Distribution and Niche Overlap of the Sable (Martes zibellina) and Yellow-Throated Marten (Martes flavigula) in Taipinggou National Nature Reserve, Heilongjiang Province, China.

The global focus on fostering harmonious interactions and promoting rational coexistence among wildlife species to uphold or reinstate biodiversity remains a prominent area of interest. We conducted a study on the sable and yellow-throated marten in Taipinggou National Nature Reserve, Heilongjiang, China, using the line transect method and infrared camera traps from 2022 to 2023. We then analyzed the overlap of their suitable habitats and niches with the aim of gaining insight into the interspecific competition between these two species. We found that the suitable habitat areas for the sable and yellow-throated marten were 55.20 km2 and 23.28 km2, accounting for 24.86% and 10.48% of the total area of this study, respectively. The overlap between the suitable habitats for the sable and yellow-throated marten was 15.73 km2, accounting for 28.5% and 67.6% of their suitable habitat, supporting our Hypothesis 1. The first principal component (Dim1) of the niche explained 35.4% of the overall variability, which is mainly related to the environmental variables "Distance from Settlements" and "Distance from Roads". Overall, 25.5% of the total variability was explained by the second principal component (Dim2), associated with "Slope" and "Distance from Coniferous and Broadleaved Mixed Forest". The niches occupied by the sable and yellow-throated marten were both off-center of the environmental background space, with the niches of the sable being larger than those of the yellow-throated marten. Schoener's D index was 0.56, indicating a high degree of niche overlap between the sable and yellow-throated marten, supporting our Hypothesis 2. Our study is helpful in terms of formulating conservation and management policies for the sable and yellow-throated marten.

Contributions of Corporate Green Space In Conserving Plant Diversity and Its Potential Usefulness: Case Study Wikasatrian Pusat Kepemimpinan

Abstract Wikasatrian Pusat Kepemimpinan, under the PT Wijaya Karya Persero Tbk management, applies sustainability principles in managing its landscape. Wikasatrian Forest is a green-forested space in the Wikasatrian that is allowed to grow and develop naturally with no or lesser management. A study on plant diversity was conducted to strengthen its conservation value. The study aimed to identify the plant variety of the Wikasatrian Forest, assess the population, and its potential usefulness for people and nature in the landscape and other needs. Data were collected using the line transect method and quadrats analysis of 10 x 10 m squares for trees, 5 x 5 m squares for saplings, and 1 x 1 m squares for ground covers, with six plots of 10 x 100 m squares, in line with the forest track. Results showed that 26 tree species from 20 families were found. On all structure levels, the Shannon’s diversity index (H) was moderate (2.53 – 2.78), and the species evenness index (E) was high (0.7 – 0.82). These showed that this area has a good ecosystem balance with diverse plant species. Most species have multiple potential uses, which are used for medicinal purposes (14) and food sources (10). Some are for materials (9) and environmental improvement (6).

Production and decomposition of mangrove litter in Dompak estuary waters, Tanjungpinang

Levels of density, production and decomposition of litter in Dompak Estuary Waters. The aim of this research is to determine the level of density, production and decomposition of Mangrove litter in the Dompak Estuary Waters of Tanjungpinang City. This research was carried out in February - March 2024. In determining the sampling points the researchers used the Purposive Sampling method. Sampling in this research used the line transect method. The results of the research show that the level of mangrove density at station 1 is 1,299 ind/ha in the medium category, station 2 is 599 ind/ha in the rare category and station 3 is 1,666 ind/ha in the dense category. Mangrove cover at station 1. Amounted to 73.83% with medium criteria in the medium category. Station 2. Amounting to 65.60% with medium criteria in the medium category and station 3 amounting to 79.93 with solid criteria in the good category and the production of mangrove litter in Dompak Estuary Waters is 3.09 gbk/m2. With a leaf composition of 7.10 gbk/m2, twigs of 0.48 gbk/m2 and flowers/leaves of 1.69 gbk/m2. Mangrove decomposition at station 1 was 21.74%, station 2 was 29.88% and station 3 was 21.14%.

Bird-Ecosystem Relationship in an Urbanizing Habitat: Implications for Conservation and Ecosystem Stability

This study explores the association between birds and their urbanizing ecosystems. The study area was divided into 4 quadrats of area 2700 m2 each. Bird species as well as number of individuals of each species were counted using the Line Transect Method. Statistical analysis of the data was performed using Windows Microsoft Excel and SPSS v.28. The investigation revealed a significant correlation (P &lt; 0.05) between bird species and the four distinct sites within the study area. These sites exhibit variations in vegetation composition and include notable features like water bodies. The findings underscore the heavy reliance of certain bird species in this region on specific types of vegetation for their survival and well-being. Removing even a single plant species could potentially disrupt the entire ecosystem. The study documented the presence of 42 bird species across 30 families, including one vulnerable species. Both local and seasonal migratory birds were observed during the research. Although the study identified a decline in bird diversity within the study area, it remains species-rich, displaying moderate to high diversity (Simpson’s Dominance Index: 0.0319; Margalef’s Richness Index: 4.0754). This research emphasizes the critical importance of conserving bird species and their associated vegetation to maintain ecosystem integrity. Strategic sustainable development practices along with habitat enrichment for birds is recommended to maintain the valuable avifaunal diversity of the study area. By highlighting the intricate relationship between birds and their habitat, the study highlights the significance of conservation efforts in safeguarding the overall health of the ecosystem.

KEANEKARAGAMAN VEGETASI ULTRABASA DI HUTAN LINDUNG NANGA-NANGA PAPALIA KOTA KENDARI

This research aimed to determine the ultra-basic vegetation diversity in the Nanga-Nanga Papalia Protected Forest, Kendari City, Southeast Sulawesi. The study was conducted in May to June 2023, covering an area of 42 hectares within the Nanga-Nanga Papalia Protected Forest. The sampling intensity was set at 5% over a study area of 2.1 hectares, resulting in 52 sampling plots arranged using the Line Transect method. The findings revealed that the ultra-basic vegetation diversity across all vegetation levels in the protected forest was classified as low, with values of 1.25 for trees, 1.22 for saplings, 1.27 for poles, and 1.13 for seedlings

(FA) Fly Ash And (CAD) Coal Ash Dams: A Potential Hotspot For Environmental Pollution Study Of Resources Emission And TheirConsequences Among Humans Inhabiting In Developmental Areas Of Over Bridges Across National Highway India

FA (FA) is a major output of Thermal Power Plants (TPP) formed when coal is burnt it produces Fly Ash (FA) trapped in Electrostatic Precipitator termed as EPA and left over at bottom of power plants. As per Government of India, this Fly ash can be directly used as better option for landfill material during any construction of Overbridges and Underpass in and around Maharashtra State. During our study, we do find apart of its major use as Land filler option it create havoc in environment. Study comprises two distinct methods Direct Observation and Line Transect Methods. To accomplish objective overall six villages were selected in and around site of construction. Our result suggest chemical contents of FA are extremely hazardous for local villagers it contains mercury,antimony , silica, aluminum oxide , ferric oxide and other oxides material acting as passive contributing factor in physical environment causing all three major types of pollution viz. air pollution ,water pollution , and soil pollution resultant consequences of human health problems .residing nearby construction highway areas .For sustainable power production there are recommended package and practices as measure to be adapted by Government of India .

Update on the terrestrial orchid flora of the Tacana volcano and close area, Chiapas, Mexico

Objective: To assess the number of terrestrial orchid species on the Tacaná volcano, Chiapas, and to empirically observe distribution/elevation patterns and ecological conditions. Design/Methodology/Approach: Random line transect sampling, over two years, for a total of 8 sites, each starting from the vicinity of rural villages. Samples were deposited in the CICY herbarium and analysed using dichotomous keys and field photographs. New records were compared with the GBIF data distribution. Results: 52 different taxa have been identified. 24 species are new records for the Soconusco region, where the Tacaná volcano is located. In this way, the Soconusco region becomes the richest Mexican region for the number of orchid species, joining a total of 351 species. Study Limitations/Implications: Building an accurate prediction model based on environmental and topographic variables could suggest microsites within the Tacaná Park that we have not visited for practical and technical reasons. Findings/Conclusions: The total number of taxa in the Soconusco region increases to 351. Terrestrial orchids are not usually studied in depth in tropical places, but they are also important in the ecological balance of the natural site. A specific inventory could show more richness of tropical ecosystems

Analisis kondisi padang lamun di Gili Balu, Sumbawa Barat

This research is conducted in seagrass meadow communities on Belang Island, Paserang Island, Kenawa Island, and Namo Island which are located in Gili Balu, West Sumbawa. Exploratory data collection was carried out in January 2022 and data processing was carried out from October to December 2022. The data collection procedure used was a training procedure for seagrass conditions using the line transect and square transect methods referring to the LIPI Seagrass Meadow Monitoring Guidebook. Data collection was carried out at each station by spreading the transect line 100 m long and placing the square transect to the right side of the line transect. Monitoring is carried out every 10 m and is carried out up to a point of 100 m. Data collection was repeated 3 times. Data processing was carried out to obtain categories and conditions of seagrass meadow compared to seagrass cover categories by the LIPI Seagrass Monitoring Guidebook and parameters of seagrass conditions by Decree of the Minister of Environment No. 200 of 2004. From the research conducted, it is found that there are 2 stations in the rare category, which are Namo and Kenawa Island, 4 stations with medium category closure of seagrass meadow, which are Paserang Island, Northwestern Belang Island, Southern Belang Island and Eastern Belang Island. The good closing category is obtained by the West Belang Island station. Seagrass meadow communities that are classified as damaged and poor are Namo Island, Kenawa Island, and Northwest Belang Island. Paserang Island and the southern and eastern parts of Belang Island are classified as damaged and unhealthy seagrass meadow. The western part of Belang Island is classified as in good and healthy seagrass condition status.

Komposisi Jenis dan Tutupan Lamun di Perairan Dusun Pandanan, Sekotong, Lombok Barat

Seagrasses can live on muddy, sandy and broken coral or rock substrates. Seagrass ecosystems are often found in areas with thick sandy mud substrates. Seagrass beds are one of the aquatic ecosystems that have high water productivity, and have a vital role for the associated biota that live around them, both as a feeding ground, nursery ground, and spawning ground. The purpose of this study was to see the species composition and cover of seagrass species in the waters of Pandanan Hamlet, Sekotong, West Lombok. Seagrass data collection was carried out at low tide, using the line transect method by making the observation path into three replicates with a length of 100 m each, a distance of 50 m each transect. The 50 cm quadrat frame is placed on the right side of the transect with a distance of 10 m between one quadrant and the other so that the total quadrant on each transect is 11 quadrants. The results showed that the composition of seagrass species found in the waters of Pandanan Hamlet, Sekotong, West Lombok as many as 7 (seven) seagrass species, namely: S. isoetifolium, C. rotundata, E. acoroides, T. hemprichii, H. ovalis, H. uninervis and H. pinifolia with Seagrass Cover in the Waters of Pandanan Hamlet Sekotong, Lombok is included in the category of moderate and rare with the percentage of seagrass species S. isoetifolium (2.78%-9.36%), C. rotundata (1.39%-6.91%), E. acoroides (7.03%-14.75%), Thalassia hemprichii (2.31%-9.66%), H. ovalis (2.5%-0.98%), H. uninervis (0.038%) and H. pinifolia (4.64%). The index of importance at the 2 stations had different values. The type of E. acoroides has the highest INP value at both stations, with values of 61.54% and 62.06% respectively. Ecological Index in the Waters of Pandanan Hamlet, Sekotong, West Lombok includes: Seagrass Diversity Index with the value obtained (1.43 and 1.65). Diversity Index with values (0.8 and 0.92) and Dominance Index with values (0.26 and 0.22).

Short Communication: Diversity, abundance, and utilization of bivalves on the south coast of Pamekasan, Madura Island, Indonesia

Abstract. Kurniawan ER, Ambarwati R, Isnaningsih NR. 2024. Short Communication: Diversity, abundance, and utilization of bivalves on the south coast of Pamekasan, Madura Island, Indonesia. Biodiversitas 25: 2454-2462. Bivalves are a group of mollusks that include clams, oysters, scallops, and mussels. Bivalves have vital roles both economically and ecologically. This study aims to analyze the diversity and abundance of bivalves in the intertidal zone of south coast of Pamekasan, Madura Island, Indonesia. Sampling was carried out at the lowest tide using the line transect method at four research stations located at Talang Siring Beach and its adjacent areas. Identification was conducted based on morphological characteristics. The data were analyzed descriptive-quantitatively. The results showed that in south coast of Pamekasan, there were 21 species of bivalves belonging to 13 genera and 8 families. The value of diversity index was 2.21 which included in the medium category. The results of the bivalve community index stated that the station 3 had the highest diversity value among other sampling stations, which was 2.2. The highest relative abundance value was found in the species Tellinides timorensis Lamarck 1818 which was 35.96%. Among the 21 species found at Talang Siring Beach and its adjacent areas, nine of them are frequently utilized by local people. Although Talang Siring Beach is managed as a tourism area, this beach is a potential habitat for bivalves.

Diversity of Gastropods in The Mangrove Forest Area of Ujung Kulon National Park

Various kinds of reseources in coastal areas are very important for us to maintain sustainability. We can find coastal area with varios kinds of ecosystems in Ujung Kulon National Park. This study aims to determine the diversity of gastropods in the mangrove forest area of Ujung Kulon National Park. Sampling used the line transect method and the purposive sampling method with low tide conditions. Sampling was carried out at three stations which are divided into three transects at each station. The transect line was drawn along 50 m with each transect made 5 plots with a size 1 x 1 m2 with a distance between plots of 10 m. This research was held in May-June 2021. The data analysis includes the index values of diversity, dominance, evenness, and abundance. The results of the gastropod obtained consist of 20 species from 7 different families so that diversity index value were included in the medium category with the highest diversity index value owned by station 1 with a diversity index value of 2,03 and the lowest diversity index value owned by station 3 with a value of 1,56. The gastropod abundance index value has an average value of 273 ind/m2.

Additive partitioning of multispecies distributional aggregation of local assemblages.

The distribution of species is not random in space. At the finest-resolution spatial scale, that is, field sampling locations, distributional aggregation level of different species would be determined by various factors, for example spatial autocorrelation or environmental filtering. However, few studies have quantitatively measured the importance of these factors. In this study, inspired by the statistical properties of a Markov transition model, we propose a novel additive framework to partition local multispecies distributional aggregation levels for sequential sampling-derived field biodiversity data. The framework partitions the spatial distributional aggregation of different species into two independent components: regional abundance variability and the local spatial inertia effect. Empirical studies from field amphibian surveys through line-transect sampling in southwestern China (Minya Konka) and central-southern Vietnam showed that local spatial inertia was always the dominant mechanism structuring the local occurrence and distributional aggregation of amphibians in the two regions with a latitudinal gradient from 1200 to nearly 4000 m. However, regional abundance variability is still nonnegligible in highly diverse tropical regions (i.e. Vietnam) where the altitude is not higher than 2000 m. In summary, we propose a novel framework that shows that the multispecies distributional aggregation level can be structured by two additive components. The two partitioned components could be theoretically independent. These findings are expected to deepen our understanding of the local community structure from the perspective of both spatial distribution and regional diversity patterns. The partitioning framework might have potential applications in field ecology and macroecology research.