Stress tests and drones: the new playbook to protect the endangered western hoolock gibbon

In the Hollongapar Gibbon Sanctuary successful Jorhat, Assam, the endangered occidental hoolock gibbon, the lone non-human ape taxon successful India, vie to beryllium heard implicit the thundering roar of a rider bid that passes done the reserve forest.

Walking done the 2,100 hectare sanctuary, visitors perceive intently for the cacophonous vocalisations of the gibbon from the precocious canopy portion our usher points to a gangly hollong histrion that this wood is celebrated for and named after.

Soon afterwards, we perceive a rustle arsenic a household of gibbons, including 2 offspring, plaything majestically overhead. Even arsenic we ticker successful awe, a faint, much threatening rumble grows louder. The gibbons scamper done the trees, and the full wood resonates with the deafening sound of a bid connected the British-era Northeast Frontier Railway enactment that splits the wood into 2 unequal parts.

The bid typifies the aggregate anthropogenic pressures, including situation loss, fragmentation and hunting, that affects the occidental hoolock gibbon crossed its situation successful the northeast Indian states of Assam, Meghalaya, Arunachal Pradesh, Manipur, Nagaland and Mizoram. Such has been its diminution implicit the past fractional a period that, according to estimates, the gibbon colonisation has plummeted from implicit an estimated 100,000 individuals to little than 5,000.

Easy people for hunters

Like successful astir of their geographical range, the gibbon’s beingness successful Assam excessively has go severely restricted owed to situation nonaccomplishment and fragmentation. Additionally, threats similar hunting person led to the taxon being listed arsenic among the astir endangered of primates successful the world. The enlargement of settled agriculture and deforestation excessively person eaten into the gibbon’s domain, accidental researchers.

While experts judge that 9 retired of 10 gibbons person disappeared implicit the past fewer decades, an nonstop colonisation number has been hard to get at, says Divya Vasudev, Co-Founder and Senior Scientist astatine Conservation Initiatives, a non-profit based successful Shillong. Gibbons are besides secondary targets for hunters owed to their large vocalisations that tin spell connected for up to 30 minutes.

The challenges faced by gibbons are emblematic of pressures connected low-lying rainforests successful Northeast India, says Rushikesh Chavan, Director of The Habitats Trust based successful Noida. Chavan adds that changing land-use and jhoom cultivation are cardinal threats to the species. “Previously, these cycles of slashing and burning would past decades, wherever forests would beryllium destroyed and past allowed to regenerate. However, these cycles person present travel down from decades to conscionable 7-10 years owed to pressures connected the section communities themselves,” helium says.

Studying genetics and stress

Despite challenges, initiatives are being undertaken to support the gibbon. Udayan Borthakur, Director and Head of Wildlife Genetics Laboratory (WGL) astatine Aaranyak, a conservation NGO successful Guwahati, says that gibbon populations person go “small and isolated” crossed their range. “We are trying to survey root populations, which could beryllium successful the Garo hills, Dehing Patkai and adjacent Hollongapar.”

Aaranyak is compiling familial information of gibbon populations done faecal substance collected successful forests to recognize whether in-breeding and in-breeding slump are causes for concern. “Through these analyses, we are trying to place the root populations. For instance, successful Hollongapar, our probe volition amusement if this existent colonisation has accrued from a smaller colonisation of a fewer individuals oregon if they are descended from a larger pre-existing population,” helium said.

WGL is besides studying accent levels of gibbon populations successful antithetic areas, to recognize whether hormones specified arsenic cortisol are higher successful populations that are successful person proximity to quality settlements and different anthropogenic pressures.

Tech-based solutions

The Habitats Trust (THT), on with Conservation Initiatives, is moving connected technology-based solutions to place gibbons successful immoderate peculiar habitat. “One of the cardinal challenges researchers face, particularly with arboreal taxon similar the gibbon, is that accepted methods similar camera traps to estimation colonisation are not feasible arsenic the animals are astir ever recovered successful the precocious canopy,” says Santhosh Pavagada, Programme Lead, Technology for Conservation astatine THT.

This necessitates the usage of alternate approaches similar bio-acoustics. Machine-learning models are being developed to place gibbon vocalisation from recorders placed wrong forests. “The exemplary volition assistance researchers by extracting gibbon vocalisations and volition supply time-stamps to rapidly navigate to areas of involvement successful each audio-file wherever a imaginable gibbon-call is being heard,” says Kishore P., an subordinate manager astatine THT.

Thermal drones are besides being explored for the anticipation of detecting gibbons successful a scenery utilizing a machine imaginativeness model. “This exemplary tin analyse 20-40 minutes of formation time, sift done the footage and place gibbons,” says Pavagada.

With a small assistance from the community

Local communities excessively are becoming progressive successful the conservation of the species. “Since overmuch of the gibbon’s situation successful the elevation tracts of Northeast India is owned and managed by nonmigratory populations, it is imperative that these communities are progressive successful conservation efforts,” says Varun Goswami, Co-Founder and Senior Scientist astatine Conservation Initiatives.

Vasudev says determination are implicit a 100 tribes, each with its ain unsocial laws and customs related to wood conservation and hunting. “Some tribes prohibit the hunting of gibbons, but we request to bring much connected committee to guarantee the extortion of the species,” she adds. “The much villages we enactment with and the much radical that amusement conservation enactment and guarantee determination is immoderate wood unafraid connected their lands, the better. The main thrust has to travel from the community.”

rohan.prem@thehindu.co.in