A checklist of land snails from the west coast islands of Sabah, Borneo (Mollusca, Gastropoda)

Sabah, situated in one of the world’s biodiversity hotspots, has the largest number of islands in Malaysia with more than 500 of various sizes and degrees of isolation. However, information on the islands’ biodiversity is limited. This study provides an up-to-date checklist of land snail species found on 24 west coast islands in Sabah. A total of 67 species (nearly 20% of the total number of land snail species in the state) representing 37 genera and 19 families is enumerated based on systematic field surveys of 133 sampling plots, BORNEENSIS database records and species checklists published between 2000 and 2016. The number of species on the islands ranges from four to 29. Labuan Island has the highest number of species (29), followed by Tiga Island (25), Mantanani Besar Island (24) and Gaya Island (23). However, the populations of some land snail species may have declined as several previously recorded species on the islands were not found in a recent systematic field sampling. This checklist is provided as a baseline inventory for future island land snail studies and to better inform biodiversity conservation plans of marine parks and other islands on the Sabah west coast

Sexual dimorphism in shell size of the land snail Leptopoma perlucidum (Caenogastropoda: Cyclophoridae)

Sexual dimorphism in the shell size and shape of land snails has been less explored compared to that of other marine and freshwater snail taxa. This study examined the differences in shell size and shape across both sexes of Leptopoma perlucidum land snails. We collected 84 land snails of both sexes from two isolated populations on two islands off Borneo. A total of five shell size variables were measured: (1) shell height, (2) shell width, (3) shell spire height, (4) aperture height, and (5) aperture width. We performed frequentist and Bayesian t-tests to determine if there was a significant difference between the two sexes of L. perlucidum on each of the five shell measurements. Additionally, the shell shape was quantified based on nine landmark points using the geometric morphometric approach. We used generalised Procrustes and principal component analyses to test the effects of sex and location on shell shape. The results showed that female shells were larger than male shells across all five measurements (all with p-values < 0.05), but particularly in regards to shell height and shell width. Future taxonomic studies looking to resolve the Leptopoma species’ status should consider the variability of shell size caused by sexual dimorphism

Microbiome and environment explain the absence of correlations between consumers and their diet in Bornean microsnails

Classical ecological theory posits that species partition resources such that each species occupies a unique resource niche. In general, the availability of more resources allows more species to co‐occur. Thus, a strong relationship between communities of consumers and their resources is expected. However, correlations may be influenced by other layers in the food web, or by the environment. Here we show, by studying the relationship between communities of consumers (land snails) and individual diets (from seed plants), that there is in fact no direct, or at most a weak but negative, relationship. However, we found that the diversity of the individual microbiome positively correlates with both consumer community diversity and individual diet diversity in three target species. Moreover, these correlations were affected by various environmental variables, such as anthropogenic activity, habitat island size, and a possibly important nutrient source, guano runoff from nearby caves. Our results suggest that the microbiome and the environment explain the absence of correlations between diet and consumer community diversity. Hence, we advocate that microbiome inventories are routinely added to any community dietary analysis, which our study shows can be done with relatively little extra effort. Our approach presents the tools to quickly obtain an overview of the relationships between consumers and their resources. We anticipate our approach to be useful for ecologists and environmentalist studying different communities in a local food web

Using a crime prevention framework to evaluate tiger counter-poaching in a Southeast Asian rainforest

Tigers are a conservation-reliant species, as multiple populations face the risk of local extinction due to poaching arising from the continued demand for their body parts. Preventing tiger poaching poses a challenge for the rangers responsible for their protection, particularly in Southeast Asia, where the protected areas are typically large, mountainous tropical forests guarded by small teams of rangers. Improving counter-wildlife crime tactics is hindered without robust evaluations, and inefficient approaches are perpetuated. We evaluate an eight-year project aiming to recover a tiger population in Peninsular Malaysia. Three distinct poaching problems by Vietnamese, Thai and Cambodian groups, differing by organisation, target species and tactics, were prioritised, and ranger counter-poaching tactics were tailored to reduce these. Applying a framework developed to evaluate crime prevention known by the acronym EMMIE, here we: (1) examine evidence our intervention was Effective in reducing the poaching threat; (2) resolve the Mechanisms by which our intervention caused a reduction in harm from poaching and how intervention effectiveness is Moderated by the three poaching types; (3) define the elements necessary for Implementation and the Economic costs involved. We found poaching incursion frequency fell 40% from baseline years to treatment years across all poaching types while poaching incursion depth declined, with disrupted incursions on average, 2.6 km (Thai) and 9.1 km (Cambodian) closer to the forest edge. However, wire snares increased from baseline to treatment years as Vietnamese poachers increased the number of snares per incursion eightfold. No poaching incursions were observed during the Covid-19 pandemic. Tiger density remained below recovery potential (0.48/100km2 in 2014 to 0.53/100 km2 in 2021) but stabilised as key females survived and were detected breeding. Leopard, sun bear, muntjac and wild boar densities remained stable. Disarming active snares and seizing an increased proportion of snares before being deployed directly reduced the potential risk of mortality to medium-large mammals once a poaching incursion began. Attributing the decline in poaching attempts to our intervention is supported for Cambodian poachers via three plausible mechanisms: increased cost of reoffending by repatriated poaching team leaders; reduction of detailed knowledge sharing and imitation by peers; general deterrence at community level from increased awareness of the elevated risk of arrest and low likelihood of enjoying rewards. We found ranger performance enhancements at three critical stages of counter-poaching were instrumental in increasing arrest certainty, this was made possible by institutionalising a learn-and-adapt cycle underpinned by a dedicated site analyst. This study highlights how investing in problem analysis and going beyond simple assumptions of deterrence can greatly enhance the effectiveness and efficiency of small wildlife protection teams

Molecular phylogeny of land snail leptopoma (gastropod: cyclophoridae) in Sabah, Malaysia

Arboreal land snail genus Leptopoma has extraordinary high distribution in Sabah, Malaysia. Despite their wide distribution, taxonomy of genus Leptopoma still largely depended on traditional morphological classification. The reliability of morphology-based classification is controversial because snail's morphology is highly influence by environmental factors due to land snail's low mobility. As a contribution solving these problem, I reconstructed the phylogeny of genus Leptopoma using molecular approach. Two mitochondrial genes (COI and 16S) were obtained from Leptopoma specimens and the phylogenetic trees were revealed by performing maximum likelihood and bayesian inference analysis. Besides, shell morphometric also investigated and mapped onto phylogenetic trees to test phylogenetic signal. All the DNA sequences and specimens details were established to Barcoding of Life Data Systems (BOLD), at the same time barcode gap within Leptopoma also investigated. A total of 17 Leptopoma specimens, which representing three nominal species and one related-outgroup species were included in this study. All phylogenetic trees strongly supported the monophyly of L. sericatum and L. perlucidum from Sabah. This results congruent with their morphological classification. Among the nine shell morphometrics, presence of inner ring in aperture exhibited significant phylogenetic signal. This suggested that presence of inner ring can be the reliable diagnostic character in delimitating Leptopoma species. Based on Kimura- 2-parameter distance model, barcode gap is present within genus where intra-specific distance is below 10% while inter-specific distance is above 10%. In overall, this study has contributed 38% of all the Leptopoma records in BOLD which enable others to access and make use of in other related research. Further study which include more specimens from every distribution range in Sabah is needed to elucidate a comprehensive taxonomic status of Leptopom

Species list and identification reference

An excel spreadsheet which provided following information: list of species, references for the species identification, occurrence of each species on every island and species richness of each island

Land snails of Leptopoma Pfeiffer, 1847 in Sabah, Northern Borneo (Caenogastropoda: Cyclophoridae): an analysis of molecular phylogeny and geographical variations in shell form

<p>SUPPLEMENTARY FILE 1. Raw data for shell morphological analysis.</p> <p>SUPPLEMENTARY FILE 2. Table S1. Specimens information; Table S2. Shell colour patterns description, Table S3 & S4. Results normality tests and homogeneity of variances tests prior to ANOVA; Table S5 & S6. Frequency data of shell qualitative characters used for chi-square tests.</p> <p>SUPPLEMENTARY FILE 3. R script for shell morphological data and phylogenetic signal analysis.</p> <p>SUPPLEMENTARY FILE 4. FASTA file for DNA sequences alignments for concatenated data of COI, 16S, and ITS-1.</p

Land snails of Leptopoma Pfeiffer, 1847 in Sabah, Northern Borneo (Caenogastropoda: Cyclophoridae): an analysis of molecular phylogeny and geographical variations in shell form

Leptopoma is a species rich genus with approximately 100 species documented. Species-level identification in this group has been based on shell morphology and colouration, as well as some anatomical features based on small sample sizes. However, the implications of the inter- and intra-species variations in shell form to the taxonomy of Leptopoma species and the congruency of its current shell based taxonomy with its molecular phylogeny are still unclear. There are four Leptopoma species found in Sabah, Borneo, and their taxonomy status remains uncertain due to substantial variation in shell forms. This study focuses on the phylogenetic relationships and geographical variation in shell form of three Leptopoma species from Sabah. The phylogenetic relationship of these species was first estimated by performing Maximum Likelihood and Bayesian analysis based on mitochondrial genes (16S rDNA and COI) and nuclear gene (ITS-1). Then, a total of six quantitative shell characters (i.e., shell height, shell width, aperture height, aperture width, shell spire height, and ratio of shell height to width) and three qualitative shell characters (i.e., shell colour patterns, spiral ridges, and dark apertural band) of the specimens were mapped across the phylogenetic tree and tested for phylogenetic signals. Data on shell characters of Leptopoma sericatum and Leptopoma pellucidum from two different locations (i.e., Balambangan Island and Kinabatangan) where both species occurred sympatrically were then obtained to examine the geographical variations in shell form. The molecular phylogenetic analyses suggested that each of the three Leptopoma species was monophyletic and indicated congruence with only one of the shell characters (i.e., shell spiral ridges) in the current morphological-based classification. Although the geographical variation analyses suggested some of the shell characters indicating inter-species differences between the two Leptopoma species, these also pointed to intra-species differences between populations from different locations. This study on Leptopoma species is based on small sample size and the findings appear only applicable to Leptopoma species in Sabah. Nevertheless, we anticipate this study to be a starting point for more detailed investigations to include the other still little-known (ca. 100) Leptopoma species and highlights a need to assess variations in shell characters before they could be used in species classification

Land snail fauna in Gunung Kuang Limestone Hill, Perak, Malaysia and its conservation implications (Mollusca, Gastropoda)

This paper presents the first land snail species checklist for Gunung Kuang (Kuang Hill), a limestone hill located next to Gunung Kanthan that is recognised as one of the most important limestone hills for its diverse land snail fauna in Kinta Valley. Samplings were carried out at five plots in Gunung Kuang. This survey documented 47 land snail species, in which six species were identified as unique to Gunung Kuang. Approximately half of the land snails from Gunung Kanthan were found in Gunung Kuang. In addition, one of six unique species from Gunung Kanthan was also found in Gunung Kuang. These rich land snail species in Gunung Kuang are similar to other hills in Kinta Valley, but it is relatively lesser than the adjacent Gunung Kanthan. In view of Gunung Kuang’s unique land snail species, and its location closest to disturbed Gunung Kanthan, Gunung Kuang should be considered in the conservation management plan for Gunung Kanthan