Habitat restoration is the greatest challenge for population recovery of Hainan gibbons (Nomascus hainanus)

Abstract

Hainan gibbons are among the world's most critically endangered primates, with a remaining population of only 35 individuals distributed across 5 social groups in the Bawangling Branch of the Hainan Tropical Rainforest National Park, China. Habitat conversion and forest fragmentation over the past 40 years have reduced their geographical distribution by 95%. In the absence of a quantitative assessment of the availability of remaining suitable habitat, it is unclear whether this species can survive to the end of this century. We used behavioral observations, ArcGIS, remote sensing, stereo optical imagery, and MaxEnt modeling to identify patterns of Hainan gibbon range use and compare changes in the distribution of suitable forest types and areas of forest fragmentation over the past 20 years (2000–2020). The results indicate that the combined range of the 5 extant Hainan gibbon groups totaled 14.89 km2. The home range of the smallest group (Group E, 3 individuals) was 1.51 km2, which likely represents the minimum home range size for this species. The remaining area of highly suitable and moderately suitable habitat totals 26.9 km2. However, habitat connectivity across the gibbon range is very low (less than 0.5), limiting the ability of Hainan gibbons to move between forest patches. The results of this study indicate that the availability of suitable habitat in Bawangling is insufficient to allow for future Hainan gibbon population growth. Therefore, immediate action must be taken to restore, reforest, and establish ecological corridors to reconnect areas of suitable habitat for these critically endangered gibbons.

Scientific activism to protect the world's primates and their environments from extinction: Introduction to the special issue

“…And it is unimaginable to contemplate the state of primate conservation in the absence of the numerous NGOs, local and national governmental officials, granting agencies, Strategic Action Plans, and dedicated primatologists who have contributed to protecting primate populations (Strier et al, 2021). In the case of individual primate species, forest communities, and local regions, there have been many successes (Chapman et al, 2018; He et al, 2023; Horwich et al, 2015; Robbins et al, 2011; Schwitzer et al, 2014; Strier et al, 2021). That said, primatologists have been advocating for primate conservation and warning of a primate extinction crisis for at least the past 60 years (Bourlière, 1962; Mittermeier, 1977), and despite these efforts, advocacy has had only a limited effect in reducing deforestation and the number of threatened and declining primate populations.…”

Improving landscape connectivity through habitat restoration: application for Asian elephant conservation in Xishuangbanna Prefecture, China

“…Thus, it can be used to evaluate the connectivity of an entire graph at the global level as well as to evaluate individual nodes and links at the local level (Galpern et al 2011). To date, many studies have applied graph theory to identify priority protection zones (Bodin & Saura 2010;Clauzel et al 2013;Serret et al 2014;He et al 2022), analyze the impact and the importance of connectivity in species distribution (Foltête et al 2012a;Tournant et al 2013), and test different vegetation restoration scenarios to improve connectivity (Clauzel et al 2015;Li et al 2017).…”

“…2014; He et al. 2022), analyze the impact and the importance of connectivity in species distribution (Foltête et al. 2012a; Tournant et al.…”

Will the new Chinese National Parks system save the world's rarest primate, the Hainan gibbon?

“…Although gibbons were previously widespread over Hainan Island, the current population is estimated at 36 individuals (as of April 2022) divided into five family groups (CGTN, 2022). Hainan gibbons once lived across the island, but now they are only found in the Bawangling section of the newly established HTRNP (He et al, 2022). As one of China's national class-one protected animals, Hainan gibbons are the jewel of the national park, and hence their survival is a key indicator of the effectiveness of HTRNP conservation management programmes.…”

“…An expert research team is focusing on the protection of Hainan gibbons, the restoration of their habitat and the development of surrounding areas. Among the critical conservation measures are vegetation restoration and the creation of corridors to connect the habitats of different gibbon groups (Li, 2020;He et al, 2022). Furthermore, a new approach to conserving Hainan gibbons relies on innovative technologies (including acoustic monitoring, data transmission, cloud storage and AI analytics for real-time data collection) to help survey and understand the primates' behaviour and monitor their movement (IUCN, 2022).…”