Cardamom (Amomum tsaoko) agroforest is important habitat for skywalker hoolock gibbon (Hoolock tianxing) in Mt. Gaoligong, Yunnan, China

Abstract

Understory plantation of cardamom (genus Amomum) is an ancient and widespread agroforestry practice in the eastern Himalayas and Southeast Asia, an area that supports high regional biodiversity. Cardamom provides an important cash income to rural people, and governments encourage cardamom cultivation as a replacement for slash-and-burn agriculture to alleviate poverty, aligning with the principles of the Globally Important Agricultural Heritage Systems (GIAHS) program initiated by the FAO. This program recognizes and supports traditional agricultural practices that contributes to biodiversity conservation and sustainable development. In this context, cardamom agroforestry not only supports local economies but also provides crucial habitat for animals, including the newly described skywalker hoolock gibbon (Hoolock tianxing). Nearly half of the remnant population of the skywalker hoolock gibbon lives in cardamom agroforest. In order to evaluate if gibbons could survive in cardamom agroforest for a relatively long term, we compared foraging behavior of gibbons over a year living in cardamom agroforests (group NA) and well-preserved forests (group BB) in Mt. Gaoligong, Yunnan, China. In response to habitat degradation caused by cardamom plantation, group NA increased feeding time and spent more time feeding on leaves. Notably, they consumed nuts of Castanopsis hystrix which is an unusual food type for gibbons. On the contrary, members of group BB rarely ate nuts though Castanopsis hystrix is abundant within its home range. However, group NA did not occupy a large home range, or travel longer in time or distance than group BB. We also monitored female reproduction of five groups for 5–13 years. Two adult females living in agroforests successfully reared two or three offspring with an inter-birth interval of five years. In addition, we surveyed group size of 16 groups (9 in agroforest vs. 7 in well preserved forests) from 2017 to 2023, and we found no significant difference in group size between habitats. Our results suggested that cardamom agroforest can sustain skywalker hoolock gibbons provided it is not too fragmented and hunting is prohibited.