Biodiversity surveys on Gunung Slamet

Posted by Christian Devenish & Stu

After several months of preparation – obtaining permits and local permissions, appointing staff, buying equipment and sorting logistics - we were finally ready to start our mountain surveys to support placement of new protected areas or extensions of existing PAs in the uplands of Java (see previous post). The project, funded by Rainforest Trust, kicked off at Slamet, a large and biologically very important mountain in Central Java. This portion of the fieldwork is also supported by Chester Zoo who have a keen interest in bird species affected by the Asian Songbird Crisis.

Into the field (Photos: Gabby Salazar www.gabbysalazar.com)

The six week stint on Slamet started with some preparations in Purwokerto, a nice town of a quarter of a million folk to the south of the mountain. A visit to the local bird market was interesting – a lot of bird market surveys get done in Java and Sumatra, especially in the huge central markets like Pramuka market in Jakarta, and Bratang market in Surabaya. Perhaps ‘underwatched’ are the small provincial markets and town shops that presumably sell a lot of birds across Java. At Purwokerto, 10-12 shops and stalls had an interesting mix of the exotic and local.

Purwokerto bird market held a variety of birds - exotic lovebirds, the expensive Jalak Putih (Black-winged Myna), as well as locally-caught birds from Slamet (Photos: Gabby Salazar www.gabbysalazar.com)

Lovebirds of all colours made up an encouraging number (as they are captive-bred) of the birds for sale, as did Zebra doves and other columbids. Some of the more expensive species were also present – including a couple of Black-winged Mynas and White-rumped Shamas, and leafbirds both from Java and Sumatra. Other birds of particular conservation concern that were certainly wild-caught included Ruby-throated Bulbul (Vulnerable), Orange-spotted Bulbul (Near-threatened), and Chestnut-capped Thrush (NT). But there was a definite local flavour to the birds on sale – with species such as Mountain Leaf Warblers, tailorbirds, Little Pied and Indigo Flycatchers, and Rufous-tailed Fantail all said to have come locally from Slamet.

Fieldwork on Gunung Slamet (Photos: Gabby Salazar www.gabbysalazar.com)

Our team assembled in a hotel in Purwokerto – Christian and Stu from MMU, field ornithologist, Ridha Junaid, from Burung Indonesia, Rick Stanley and Gabby Salazar, experienced PhD students/wildlife recorders from USA, Ganjar and Arya, students from the local university, and guides Pak Karso, Pak Karbo and his son, and a team of porters – with all the equipment and rice, we were not travelling light. A quick trot through paddies and a waterfall recreational area – and we were at the forest edge, at around 700 m a.s.l. The northern side of the mountain is largely deforested below 2,000 m – hence our keenness to survey the steep southern slopes which have retained much of their forest, and we hope, its wildlife.

Javan Gibbons were recorded several times around 7-800 m (Photo: Gabby Salazar www.gabbysalazar.com)

Even from our camp close to the edge of the forest, we could see and hear both Javan Gibbons and Javan Hawk-eagles. We had several sightings in the local area, boding well for their populations on the mountain. During the first day, an important job was to test both the camera traps and audio recorders. Both sets of tech seemed to be working OK so we deployed all 14 recorders and 20 cameras along two transects ranging from 700 m to over 1,200 m a.s.l. This is quite low in the schemes of things at Slamet – perhaps more of the interesting and target species will be located higher up, perhaps in the 1,500-2,200 m altitudinal range. Nevertheless, some good sightings were had (Javan Trogon; Pin-tailed Parrotfinch), and good mixed flocks encountered which bodes well for fieldwork higher up the mountain. Less encouraging were accounts from local people about the extent of trapping on the mountain – the whole area appears to be peppered with small hunter trails and there seem to be very few places that are inaccessible to trappers.

Above - sonogram of Javan Gibbon caught on one of the recorders; Below - the real thing - audio associated with this record.

We left the team, having finished Site 1 on Mountain 1. The team has been joined by Bas van Balen and Fajar, a research assistant from Burung with experience camera trapping on Sumatra– they head further up the mountain on a different trail, spending around two weeks camping up as high as 2,200 m. The fieldwork on each mountain will be divided up into sites, each taking around a week to complete. After arriving and making camp, the first day will be spent in two teams positioning the audio recorders and cameras. Detailed habitat data will be gathered at each recorder location – details of tree girths, understorey density and presence/absence of a whole range of habitat features (e.g. bamboo, rattans).

The first mammal caught on our cameras - the poorly known Sunda stink badger Mydaus javanensis

 The cameras and recorders will be left out to record constantly for three full days and nights so there will be terabytes of data to be analysed. That leaves around three days before taking the tech back in to search more extensively across the site for the key species of birds, mammals and frogs that we are targeting. We will record the GPS locations of these species and take habitat data from those points to allow us to build a picture of their spatial distribution, habitat requirements, and reaction to human pressures. All this, in turn, will, along with detailed socio-economic data from local stakeholders, feed directly into decisions about where additional protected areas should be ideally located to secure Java's most important montane wildlife populations.