Artificial canopy bridges improve connectivity in fragmented landscapes: The case of Javan slow lorises in an agroforest environment

Canopy bridges are increasingly used to reduce fragmentation in tropical habitats yet monitoring of their impact on the behavior of primates remains limited. The Javan slow loris (Nycticebus javanicus) is endemic to Java, Indonesia, where the species most often occurs in human-dominated, highly patchy landscapes. Slow lorises cannot leap, are highly arboreally adapted, and are vulnerable on the ground. To increase arboreal connectivity, as part of a long-term conservation project in Cipaganti, West Java, we built and monitored seven slow lorises bridges of two types—waterline or rubber—and monitored their use by seven adult individuals from 2016 to 2017. Motion triggered camera traps collected data for 195 ± standard deviation (SD) 85 days on each bridge. We collected 341.76 hr (179.67 hr before and 162.09 hr after the installation of bridges) of behavioral and home range data via instantaneous sampling every 5 min, and terrestrial behavior (distance and duration of time spent on the ground) via all occurrences sampling. We found that slow lorises used bridges on average 12.9 ± SD 9.7 days after their installment mainly for traveling. Slow lorises showed a trend toward an increase in their home range size (2.57 ha before, 4.11 ha after; p = 0.063) and reduced ground use (5.98 s/hr before, 0.43 s/hr; p = 0.063) after implementation of bridges. Although the number of feeding trees did not change, new feeding trees were included in the home range, and the proportion of data points spent traveling and exploring significantly decreased (p = 0.018). Waterline bridges serve a purpose to irrigate the crops of local farmers who thus help to maintain the bridges, and also ascribe value to the presence of slow lorises. Other endemic mammal species also used the bridges. We advocate the use and monitoring of artificial canopy bridges as an important supplement for habitat connectivity in conservation interventions.     

The sticky tasty: the nutritional content of the exudativorous diet of the Javan slow loris in a lowland forest

Primates - Plant exudates are an important food source for many primates. The Critically Endangered Javan slow loris (Nycticebus javanicus) was previously found to prefer Acacia decurrens exudate...     

Pleistocene isolation and recent gene flow in Haliotis asinina, an Indo-Pacific vetigastropod with limited dispersal capacity

Haliotis asinina is a broadcast-spawning mollusc that inhabits Indo-Pacific coral reefs. This tropical abalone develops through a nonfeeding larval stage that is competent to settle on specific species of coralline algae after 3-4 days in the plankton. Failure to contact an inductive algae within 10 days of hatching usually results in death. These life cycle characteristics suggest a limited capacity for dispersal and thus gene flow. This makes H. asinina particularly suitable for elucidating phylogeographical structure throughout the Indo-Malay Archipelagoes, and eastern Indian and western Pacific Oceans, all regions of biogeographical complexity and high conservation value. We assayed 482 bp of the mitochondrial cytochrome oxidase II gene in 206 abalone collected from 16 geographically discrete sites across the Indian and Pacific Oceans and Indo-Malay Archipelagoes. DNA sequence variation was analysed via population genetics and phylogenetics, and by nested clade analyses (NCA). Our data resolved clear phylogeographical breaks among major biogeographical regions, with sequence divergences ranging from a high of 3.7% and 3.0% between Indian and Pacific sites and Pacific and Indo-Malay sites, respectively, to a low of 1.1% between Indian and Indo-Malay sites. Despite the apparent limited dispersal capacity of H. asinina, no finer scale phylogeographical structure was resolved within the respective biogeographical regions. However, amova and NCA identified several significant associations between haplotypes and geographical distribution, most notably higher gene flow among geographical populations associated with major ocean currents. Our study provides further evidence that larval dispersal capacity alone is not a good predictor of population genetic structure in marine invertebrates. We infer instead that a combination of historical events (long-term barriers followed by range expansion associated with Pleistocene sea level changes) and contemporary processes (gene flow restricted by life history and oceanography) have shaped observed patterns of H. asinina phylogeography.     

The relative influence of diffuse- and point-source disturbances on a small upland stream in East Java,Indonesia: a preliminary investigation

The relative effects of a diffuse disturbance (alteration of land use from forest to plantation) and a point-source disturbance (a village and its associated coffee-processing plant, within the plantation) on longitudinal variation in water chemistry and macroinvertebrate community composition were assessed in Kali Dinoyo, a small upland stream in East Java, Indonesia. Four sites were sampled. The catchments of the two most-upstream sites were covered primarily by rainforest, while the two lower sites fell within a coffee plantation. The lowest site was downstream of a small village and its associated coffee-processing plant. Most of the variance in all water quality variables and in several community composition measures was explained by the difference between plantation and forest sites. Comparatively small differences in total suspended solids and macroinvertebrate community composition were observed downstream of the village. Diffuse disturbances associated with land clearance and plantation agriculture therefore appear to have a larger impact on the ecology of Kali Dinoyo than the point source impacts associated with the village. More robust and powerful study designs to formally test these findings are discussed.