FINAL REPORT Biodiversity Monitoring: Batang Toru river area, PT. North Sumatra Hydro Energy Target Area South Tapanuli, North Sumatra A new species to science of Thismia sp. nov. encountered in the Northern survey area. © Ronald Siagian; A Rafflesia sp. bud encountered in the target area, and a White-crowned hornbill caught on camera trap. 31st of August 2015 Prepared by PanEco/Yayasan Ekosistem Lestari requested by ERM/ PT. North Sumatra Hydro Energy Executive Summary As part of a planned construction of a hydropower dam and associated facilities with an operational capacity of 500 MW on the Batang Toru River, South Tapanuli Regency, North Sumatra Province, to be implemented by PT. North Sumatra Hydro Energy (NSHE), a comprehensive baseline biodiversity assessment has been requested in order to seek international finance and comply with international standards. In order to assess the biodiversity values with the project area, a detailed aquatic and terrestrial biodiversity baseline is required to be undertaken. The Environmental Impact Assessment (AMDAL, 2014) identified major environmental impacts from the proposed project, including: loss of 360 ha natural vegetation; change in habitats; reduced of water flow and others. The target area is an integral part of the Batang Toru Ecosystem, renowned for its recently discovered genetically unique orangutan population and rich biodiversity. These biodiversity surveys are intended to provide biodiversity baseline data in the target area prior to disturbance activities and are aimed to cover a combination of habitat types, locations, and seasons within the forest areas west and east of the Batang Toru river. The current surveys will cover several locations along the west (Southern, Middle, Northern) and east side of the Batang Toru river (Corridor and several river tributaries), and will be carried out in both the wet and dry season (February 2015 till end of July 2015). The surveys consist of camera trapping for terrestrial mammals, orangutan nest surveys, specific siamang/gibbon vocal surveys, sun bear sign surveys, other ad-hoc mammal records and records of their sign, botanical surveys, bird diversity surveys, reptile/amphibian surveys, freshwater fish and other aquatic fauna (plankton/benthos). Here we report on the wet season findings of these surveys carried out between 7th February-1st August 2015. Unfortunately intense land speculation related to the planned PLTA activities had commenced prior to these surveys and some land-clearing activities were ongoing during the surveys. The land speculation and clearing activities, as well as increased human presence, and the sound of chainsaws from various angles might have affected various mammal species living in the area. For instance, species not living in strict territories are likely to have moved away from the disturbance. Other taxa (birds, reptiles/amphibians) might have been affected by intensive clearing of undergrowth for land speculation, and/or catching for trade. ii Objectives The biodiversity baseline assessment is carried out in order to: 1. Provide an updated biodiversity study for the Project Area, being the NSHP areas covering inundation area, power house, downstream water outlet, access road and river area, and the Area of Influence of the project, being the surrounding area that has a direct relationship with the project location (defined as within 10 kilometers of the project or defined natural boundaries such as watershed boundaries or mountain ranges). 2. Determine the presence or likely presence of aquatic and terrestrial Modified and Natural habitats and species of conservation significance; 3. Provide an assessment of orangutan ecology in the Project Area and Area of Influence, covering population prediction, distribution, key habitat areas and food trees present, and other ecological data. 5. Conduct an assessment of the condition (quality) of terrestrial and aquatic habitats within the Project Area and Area of Influence against a habitat baseline condition (what it would naturally be like without anthropogenic influence). One of many small waterfalls encountered in the survey area © Ronald Siagian iii Key findings: Key Mammal survey findings: A total of 47 mammal species [including Pteropus vampyrus, Giant fruit bat] were encountered during the biodiversity surveys on both the west and east side of the Batang Toru river [South-Middle-North survey locations on the West side of the Batang Toru river; Corridor location on the East side of the Batang Toru river] between February- August 2015. 15 mammal species encountered throughout the target area are listed under the IUCN Red List as Critically Endangered, Endangered or Vulnerable: 1) Sumatran tiger Panthera tigris sumatrae CE 2) Sumtatran orangutan Pongo abelii CE 3) Pangolin Manis javanica CE 4) Asian Tapir Tapirus indicus EN 5) Mitred leaf monkey Presbytis melalophos EN 6) Agile gibbon Hylobates agilis EN 7) Siamang Symphalangus syndactylus EN 8) Sambar deer Cervus unicolor VU 9) Serow Capricornis sumatraensis VU 10) Binturong Arctictis binturong VU 11) Banded Palm Civet Hemigalus derbyanus VU 12) Marbled cat Pardofelis marmorata VU 13) Malayan sun bear Helarctos malayanus VU 14) Pig tailed macaque Macaca nemestrina VU 15) Slow loris Nycticebus coucang VU 21 mammal species encountered during the surveys are protected under Indonesian law; A combined 25 mammal species encountered during the surveys are either IUCN Red Listed or protected under Indonesian law; Sumatran orangutan (Pongo abelii, IUCN Critically Endangered, CR) nests were found throughout the 4 survey locations [North-Middle-South on the west side of the Batang Toru river; Corridor on the east of the Batang Toru river] along 48 transects (total length 23.775 km). A total of 213 nests were encountered along the transects [South, Middle, North, Corridor locations] with an additional 62 nest encountered randomly outside of the transects; Orangutan densities in the target area were calculated as 0.7 individuals/ km2 on average. Densities were found highest in the Southern survey location 0.95 ind/ km2 (95% CI: 0.54 – 1.68 ind/ km2) and are 26-57 % times higher in the PLTA target area than in other areas previously surveyed in the Batang Toru forest ecosystem; Direct observations were made of 11 orangutans (a party of 3 animals consisting of a mother and infant and a sub-adult male foraging in a large fig tree in the Southern survey location; and one sub-adult individual encountered towards the Middle survey location; a party of 5 animals in the Northern survey location consisting of 2 adult flanged males, a female with baby and a juvenile; and two separate observations of single individuals in the North); iv Long calls of adult male orangutans were heard on 27 occasions; A Sumatran tiger (Panthera tigris sumatrae, IUCN Critically Endangered, CE) was heard calling on the 16th of March 2015 in the southern survey location with a subsequently footprint found, and another observation of a footprint on the 25th of March; Pangolins (Manis javanica, IUCN Critically Endangered, CE) were caught on camera trap on 13 independent events, in three of the four key survey locations; Density of resident Agile gibbon (Hylobates agilis, IUCN Endangered, EN) groups was found to be high throughout the survey area (15.5 ind/ km2), with highest densities found in the Southern survey area (16.5 ind/ km2); Siamangs (Symphalangus syndactylus, IUCN Endangered, EN) were heard daily throughout all survey areas and frequently observed, with overall densities calculated as 8.7 ind/ km2, and highest densities found in the Southern area (11.7 ind/ km2); Mitred leaf monkeys (Presbytis melalophos, IUCN Endangered, EN) were observed almost daily throughout the survey area with a total of 76 direct observations made throughout the survey period, with another 13 events of leaf monkeys caught on camera traps; A total of 104 camera trap sessions were carried out in the Southern, Middle, Northern and Corridor surveys areas. Data from 2972 trap nights have been entered, covering 2153 independent photographic events of wildlife; Tapir (Tapirus indicus, IUCN Endangered, EN) scats and footprints was encountered throughout the survey area [12 events of scats and/or footprints], as well as 2 camera trap events of tapir were obtained in the Middle survey location; Serow (Capricornis sumatraensis, IUCN Vulnerable, VU) was caught at several camera trap locations in the Middle survey location on 6 separate events location, with 4 additional sign recorded (footprints/scat); Marbled cat (Pardofelis marmorata, IUCN Vulnerable, VU) was caught on camera trap on 6 separate occasions in two survey area [both east and west of the Batang Toru river]; Pig-tailed macaques (Macaca nemestrina, IUCN Vulnerable, VU) are one of the most common species caught on camera traps with a total of 458 individual events; Sun bear (Helarctos malayanus, IUCN Vulnerable, VU) sign (claw marks and feeding sign) was encountered throughout the southern target area and 5 camera trap pictures was obtained in the three of the four survey area; Sambar deer (Cervus unicolor, IUCN Vulnerable, VU), including female with young were caught on camera trap on 45 independent events, with an additional 43 events of footprints/faeces; Two direct observations were made of the Binturong (Arctictis binturong, IUCN Vulnerable, VU) and 6 camera trap pictures were obtained; Tiger prey species (sambar, barking deer, pigs, and pig-tailed macaques) were among the most common mammal species caught on camera traps in the area (combined 738 independent camera trapping events); Two direct observations were made of the slow loris, Nycticebus coucang, (IUCN Vulnerable, VU); Three direct observations were made of the flying lemur, Galeopterus variegatus; v Photographs were taken of Exilisciurus exilis the Least Pygmy Squirrel, considered a Bornean endemic, though collected in Sumatra some 170 years ago; further photographic evidence is sought; Several roosting trees of Pteropus vampyrus (giant fruit bats) were encountered near the Batang Toru river near the middle survey area, and fruit bats were seen at dusk to fly over the southern survey area in large flocks.