Factors Associated with Detection Probability and Site Occupancy of the Long-Tailed Skink (Eutropis longicaudata) in the Aluoi Area, Central Vietnam

Lizard species are rarely detected with perfect accuracy, regardless of the method employed. Nondetection of a species at a site does not necessarily mean the species was absent unless the detection probability was 100%. We assessed the influence of site covariates (less disturbed habitat and disturbed habitat) and sample covariates (temperature, humidity, rainfall) on the occupancy of Eutropis longicaudata in the Aluoi area, central Vietnam. Based on detection/nondetection data over nine visits at 40 less disturbed sites and 39 sites with disturbed habitats, the distribution of E. longicaudata was estimated using site occupancy models. From the best model, we estimated a site occupancy probability of 0.595, a 12.05% increase over the naive occupancy of 0.531 at which E. longicaudata skinks were actually observed. The site covariate of the less disturbed habitat was an important determinant of site occupancy, which was not associated with the variable of disturbance habitats. In the combined AIC model weight, p(precipitation), p(temperature), and p(humidity) have 92%, 36%, and 21% of the total, respectively; providing evidence that environmental conditions (especially precipitation) were important sample covariates in modelling detection probabilities of E. longicaudata. In terms of occupancy probability, the combined weight for the ψ(less disturbed habitat) model and the ψ(disturbed habitat) model were 60% and 32%, respectively. Our results substantiate the importance of incorporating detection and occupancy probabilities into studies of habitat relationships and suggest that the less disturbed habitat associated with weather conditions influence the occupancy of E. longicaudata in central Vietnam.

Diversity of Amphibians and Reptiles in Various Anthropogenic Disturbance Habitats in Nantu Forest, Sulawesi, Indonesia

The Nantu Forest in Gorontalo Province, Sulawesi, Indonesia holds one of the few remaining pristine habitats in the island. The reserve is surrounded by human habituation which provide opportunity to study the impact of forest lost on biodversity. In addition, data on Nantu mostly focused on big mammals, as there is no previous herpetofauna survey at the area. Sampling of amphibian and reptile was conducted in June 2013 and in May–June 2014 using Visual Encounter Survey method, glue traps and transect sampling in seven different sites at the eastern part of Nantu. We categorized four habitat types based on human disturbances: high disturbed habitat (HDH), moderate disturbed habitat (MDH), low disturbed habitat (LDH) and pristine habitat (PH). A total of 680 individual amphibians (4 families; 17 species) and 119 individual reptiles (9 families; 29 species) were recorded. Species richness and species composition for amphibians and reptiles differs according to the level of human disturbances. Low level disturbances habitat demonstrated the highest diversity of amphibians and reptiles, whereas as expected, high distubed habitat showed the lowest diversity. Anthropogenic pressures in forest will decrease species richness of amphibian and reptiles. Although most amphibian and reptiles will be able to persist in low disturbances habitat, forest-dependent species will be lost when pristine forests are disturbed.

Spatiotemporal dynamics of terrestrial invertebrate assemblages in the riparian zone of the Wewe river, Ashanti region, Ghana

This study assessed invertebrate response to disturbances in the riparian zone of the Wewe river, using geometric series, rarefaction, Renyi diversity, and CCA models. We sampled 2,077 individuals (dry season) and 2,282 (wet season) belonging to 16 invertebrate orders. The severely disturbed habitat registered the highest individuals (n = 1,999), while the least was the moderately disturbed habitat (n = 740). Seasonal assemblages were not significantly different. Fire, farming, tree felling, and erosion explained 66.8% and 60.55% in the dry and wet seasons, respectively, of variations in invertebrate assemblages. This suggests threats to the invertebrate community and the riparian ecosystem health by anthropogenic interventions.

Globally invasive populations of the clonal raider ant are derived from Bangladesh

Identifying the native range of invasive species is useful to understand their evolution and natural history, as well as to develop new methods to control potentially harmful introduced organisms. The clonal raider ant, Ooceraea biroi , is an introduced species and an increasingly important social insect model organism, but its native range remains unknown. Here, we report a new series of O. biroi collections from Bangladesh, Singapore, Vietnam and China. We use a molecular phylogeny constructed with five gene fragments from 27 samples to determine that invasive lineages of O. biroi originated in Bangladesh. These lineages may have spread from Bangladesh via the historically significant Bay of Bengal shipping ports. Ooceraea biroi shares multiple features of its biology with other introduced ants, including parthenogenesis, retention of heterozygosity and presence of multiple egg-layers in the colony. Using laboratory rearing and microsatellite markers, we show that colonies collected from disturbed habitat in Bangladesh have these traits in common with colonies from the invasive range. Ancestral populations with sexual reproduction in primary habitats either remain to be discovered or have gone extinct. Our findings advance our understanding of the global spread of the clonal raider ant and highlight a suite of general traits that make certain ants prone to becoming invasive.

Population structure of Geodorum densiflorum (Orchidaceae) in relation to habitat disturbance and vegetation characteristics

Nurfadilah S. 2020. Population structure of Geodorum densiflorum (Orchidaceae) in relation to habitat disturbance and vegetation characteristics. Biodiversitas 21: 1422-1431. Habitat disturbance can have large impacts on the persistence, survival, and growth of plant populations, particularly for orchids, one of the most threatened plant families. The present study aimed to investigate the impact of habitat disturbance on the population of a terrestrial orchid, Geodorum densiflorum (Lam.) Schltr, in terms of its population structure which is important in determining population viability for the species survival. The species occurred in three habitat types (disturbed habitat i.e. totally converted habitat into cananga plantation, burnt habitat, and undisturbed habitat). Plots of 2 m x 2 m were established in these three habitat types and the population structure of G. densiflorum in these three habitat types was analyzed. After analysis, three population types could be distinguished (i) 'regressive population' in disturbed habitat characterized by the absence of seedlings and dominated by generative adults, (ii) 'dynamic population' in burnt habitat characterized by a large proportion of young individuals (seedlings and juveniles) relative to the adults, and (iii) 'normal population' in undisturbed habitat characterized by the prevalence of adults but a small proportion of young individuals. The variation in the population structure of G. densiflorum appears to be related to the difference in vegetation characteristics of the three habitat types. The absence of seedlings of G. densiflorum in disturbed habitat was related to the grasses dominating vegetation that could inhibit seedling recruitment of G. densiflorum. Grasses were absent and hardly occurred in burnt habitat and undisturbed habitat allowing seedling recruitments of G. densiflorum in these habitat types. The highest seedling proportion and density of G. densiflorum were observed in burnt habitat as burning can remove aboveground biomass and reduce competition with surrounding vegetation providing safe microsites for seedling establishment and recruitment. The present study has implication in the orchid conservation and provide recommendation for the orchid conservation (i) to avoid totally converted habitat as it had consequences on the absence of seedling recruitment (ii) to perform mowing and managed burning to increase seedling recruitment of G. densiflorum which is important for population enlargement, persistence, and survival.

Nowe stanowisko Erechtites hieracifolia (Asteraceae) koło Różana w Puszczy Białej (Polska północno-wschodnia)

A new locality of Erechtites hieracifolia was found near Różan in north-eastern Poland. The species grows in fresh coniferous forest in a strongly disturbed habitat. This is the second known locality of this species in north-eastern Poland.