Integrated assessments call for establishing a sustainable meta-population of Amur tigers in northeast Asia

Abstract

With most large carnivore populations and habitats suffering massive declines across the world, efforts to restore their populations in the wild are of high conservation priority. China attaches great importance to protecting Amur tigers and has made considerable progress towards this goal, but most efforts have been focused on the single Laoyeling landscape. Here we assess all four major forested landscapes (including Laoyeling, Zhangguangcailing, Wandashan and Lesser Khinghan Mountains) that may be suitable for tigers in northeast China. Between 2013 and 2018, in total 55 wild Amur tigers were recorded through camera trap surveys and 30 individuals were identified through genetic analyses. The finite rate of increase of the population in the Laoyeling landscape, the only landscape with a breeding population, fluctuated greatly, but averaged 1.51. Total habitat used by Amur tigers during this period amounted to 47,813 km². We estimated that based on density and home range sizes in nearby Russia, these landscapes could support 310 tigers, including 119 resident breeding females. However, prey density, especially of preferred prey, was extremely low, and likely a primary constraint to population recovery in landscapes other than Laoyeling, especially the Wandashan and Lesser Khingan Mountains landscapes. To achieve the goal of a large meta-population of Amur tigers across northeast Asia, in addition to prey restoration, we recommend extensive landuse planning, reducing anthropogenic impacts, improving ecology connectivity, and extensive international cooperation, as well as a feasibility assessment for introducing orphaned cubs as a means of speeding recovery in landscapes without breeding females.

Introduction

Currently, most of the world's large carnivores are listed as threatened by the International Union for Conservation of Nature (IUCN) and are still suffering population declines and habitat loss (Ripple et al., 2014). The tiger (Panthera tigris) is the most endangered of the large cats (Goodrich et al., 2015), with a total population which has declined from an estimated 100,000 individuals at the beginning of the 20th century to no more than 3500 tigers at the beginning of the 21st century (Seidensticker, 2010). Furthermore, about 93% of their historical habitat has been lost, with rapid land clearing continuing in the new century (Goodrich et al., 2015). In 2010, 13 tiger range countries agreed to double the world's wild tiger population by 2022, a commitment which has received worldwide attention (Global Tiger Recovery Program, 2010). Although countries like India claim progress towards recovery (Sharma, 2019), estimates are confounded by methodological issues (Harihar et al., 2017; Gopalaswamy et al., 2019) and are far from sufficient in achieving the goal of doubling tigers across the range. More ambitious conservation plans are needed.

Four subspecies of tigers occurred in China at the beginning of the 20th century, including Amur tigers (Panthera tigris altaica) with about 500 individuals (He et al., 1997; Meng et al., 1995). Although the Chinese government banned tiger hunting in the 1950s and listed this species as a protected species in 1977 (Meng et al., 1995), tiger populations continued to shrink. By 1976 there were an estimated 151 individuals remaining (He et al., 1997), and by 2000, the only remaining population was an estimated 12–16 individual Amur tigers found along the border with Russia (Ma and Zhang, 2009). Since then, the national Natural Forest Protection Project (NFPP) (Jiang et al., 2017) has led to the relocation of forest workers and the recovery of forests. Assessments of how tigers might recover in northeast China have also been developed, which have mostly focused on the Changbai Mountains of eastern Jilin and southeastern Heilongjiang Provinces (Luan et al., 2011; Hebblewhite et al., 2012; Wang et al., 2016a).

The creation of Hunchun Amur Tiger National Nature Reserve, among others (Shevtsova et al., 2018), improved anti-poaching efforts, and compensation for human-tiger conflicts have further helped to ease the pressures facing tigers in northeast China (Jiang et al., 2017). Consequently, camera trap surveys from August 2012 to July 2014 detected 26 individual tigers in the Laoyeling (LYL) forest landscape in north of Changbai Mountains (Wang et al., 2016b) and the presence of breeding females was also confirmed in 2013 (Jiang and Qi, 2014; Jiang et al., 2017). With indications of recovery underway, the Chinese government created the Northeast Tiger Leopard National Park (NTLNP) in 2016 in the eastern LYL forests, abutting the border with Russia (Northeast Tiger Leopard National Park, 2016). At 14,600 km², this park includes most of the current Amur tiger habitat in LYL, including Hunchun Amur Tiger National Nature Reserve, and represents the largest protected area for tigers in the world.

Currently, the Chinese government and the public both focus their main attention devoted to Amur tiger conservation on the NTLNP or the extent of the Changbai Mountains (McLaughlin, 2016; Northeast Tiger Leopard National Park, 2016). Meanwhile, there are at least three other landscapes in northeast China which have conservation potential, yet have been only been partially assessed for their capacity to support tigers (Zhang et al., 2013; Li et al., 2016) (Fig. 1). A viable population of tigers is thought to require at least 83 breeding females (Chapron et al., 2008), which is more than twice the capacity of NTLNP based on the average home range size of tigresses in Russia (Goodrich et al., 2010; Hernandez-Blanco et al., 2015). Therefore, it is crucial to assess the potential for connectivity and the recovery of tigers across multiple landscapes in order to achieve a meta-population of sufficient size and long-term viability. Presently in Russia, tigers occur along the boundaries of three of the four landscapes in China, representing a source for recovery (Fig. 1), and tigers have been reported in each of these four forested landscapes in China. However, the area of potential habitat, existing prey densities, and the possibility of connectivity between all four landscapes will ultimately be key determinants in the recovery process and feasibility across a much larger region, and hence, also aid the prioritization of conservation resources.

In this study, information of wild Amur tigers and their ungulate prey were continuously collected throughout all potential tiger landscapes across northeast China since January 2013 through a comprehensive survey method including camera traps, transects survey, snow-tracking and telephone hotline. On the basis of these data, we attempt to ascertain the status of tigers in China, to evaluate prey populations, potential tiger populations, and the needed linkages to Russian landscapes for the creation of a meta-population of tigers across northeast Asia. Following this comprehensive synthesis, we provide clear recommendations for the continued recovery and persistence of the Amur tiger in northeast Asia, especially in China.