The impact of hunting on tropical mammal and bird populations

Benítez-López et al. (Report, 14 April 2017, p.180) used a meta-analysis to synthesize 176 studies to assess the impact of hunting on tropical mammal and bird populations. We argue that hunting happened is not only for material demand (wild meat) as authors have mentioned, but also for spiritual reasons (like religious wildlife release) which is prevalent in many Asian countries.
 
Benítez-López et al.(1) report that hunting-induced declines of mammal and bird populations is the major driver of biodiversity loss across the tropics. Their findings show that better accessibility to major towns leads to higher hunting pressure due to the wild meat traded there. They call for urgently needed strategies to manage wild meat hunting sustainably. While we agree with most statements, we think their estimate is still an underestimate. That is because they ignored the fact that hunting is not only for food purposes (meat demanding), but often also for religious purposes (spirit demanding) which is especially prevalent in Asia (2-6). In some areas it has become commercialized, leading to large-scale trapping and trans-border trading (2-4, 7, 8).
The release of wild animals for spiritual or religious purposes has been a traditional practice in many East and South-east Asian countries, especially in those with Buddhist influence (2, 4, 6, 9, 10), such as Singapore, Indonesia, Malaysia, Thailand, Cambodia, Vietnam, Nepal, Lao PDR, India and China (China mainland, Hong Kong, Taiwan) (2, 3, 5, 7, 9-11) (Fig. 1). It is also well documented in Australia, Canada, and the United States (5). Wildlife release is known as merit release, prayer release or by theChinese name 'Fang Sheng'. People who practicipatein this practice believe they can accrue merits by freeing captive animals into the wild as a form of prayer to the gods, which will enhance personalkarma and promote advancement towards a state of enlightenment (3, 4) (activity hold as Fig. 2 show). However, in many places, this act of benevolence became twisted and gave rise to acommercial trade of "Release – Purchase; Sell – Capativate" through wildlife that are captured solely for the purpose of release (3, 4, 7, 8, 12). These released wildlife are primarily birds, fishes, frog, turtles, snakes, and mamals (2, 3, 6).

Fig.1 Geographical location of countries which release wild animals for religious purposes, such as those found in Buddhism. Countries recorded with religious wildlife release in recent or history are shown in red.
Though the trade that provides the animals for this activity are limited, millons of animals are sold every year, based on data collected from overthe past decades in Asia. McClure & Chaiyaphun (1971) (7) estimated already that for time period 1967 to 1968, 300,000 birds representing 370 species were sold annually at the BangkokSunday Market in Thailand (but did not distinguishbirds sold for merit release, as pets, or as food); Layton (1991) (13) recorded the release of 10,000 Java Sparrows (Padda oryzivora) from a temple in Singapore by asingle Chinese man celebrating the birth of his firstborn son; Chen (1995) (14) recorded 128,000 birds captured for release each year and found 28.8% of 73 temples organized prayer animal releasesin Taichung City, Taiwan; Ahmed (1997) (10) found from 64 surveys in 57 trading establishments and trapping areas that a huge variety of birds were sold for release in India; Chan (2006) (3) estimated annualsales of 680,000-1,050,000 birds for release in Hong Kong. Gilbert et al. (2012) (4) observed the annual sale of 688,675 individuals (57 species) for relaese in Phnom Penh, Cambodia from March 2006 to April 2007, and 12,751 individuals were Asian Golden Weavers (Ploceus hypoxanthus) which are classified as globally Near Threatened by IUCN. Religious releases in China mainland are quite widespread from the south to north of China, as reported in newspapers and websites. According to the statistics of Tencent QQ (also known as QQ), the China's largest social network, we found there are 3,458 QQ wildlife release groups including 554,320 users across China (data statistics up to10th May, 2017), except Macao and Taiwan, for which data is lacking. Though some people will join several groups at the same time, these data still offer an insight and trend that the quantatity of participants in the release activity is 'large' in China. Impact can not be ignored!
Fig. 2 Wildlife release practices and the ending of released wildlife. (A) Wildlife release practice in Taibai National Forest Park in Shaanxi Province (Photo by Fengqin Yu, 2011); (B) Birds are waiting for releasing in Jiangxi Province (Photo by Fengqin Yu, 2009); (C) Dead birds after releasing in Qinghuangdao, Heibei Province (Photo by Fengqin Yu, 2009); (D) a released Magpie (Pica pica) is eating a released Siskin (Carduelis spinus) in Yellow River wetland, Henan Province (Photo by Yumin Guo, 2010)
The religious release is akin to "releasing lives" but not "saving lives" (3). An unknown, but likely significant, amount of animals died in the whole trade and release process. Released individuals may die during the trapping process or during the transportation to other provinces or countries. Finally, only a small percentage of animals live to be released (e.g. as few as1 in 20 birds survive (15)), and may yet still die due to predation, poor health condition, unsuitable and/or harsh enviromenal conditions (3, 15) after the release. In addition, infectious diseases may easily spread in a packed and unhygienic housing condition and spread to the wild populations if they are released (3, 4). If these animals survive, this may lead to the establishment of exotic species in new enviroments and threatening of local wildlife abundance.For example, Chinese bulbuls (Pycnonotussinensis) do threaten local Styan's bulbul (Pycnonotustaivanus) in the Taiwan Province (2), as have American bullfrogs (Lithobates catesbeianus) and red-eared slider turtles (Trachemys scripta elegans) been invasive species in China (6).
Having better and more sustainable strategies to manage wild meat hunting is essential to protect global wildlife (1). While it may not be enough in Asia, where wildlife releases a traditional practice and leads to commercialized hunting (2-4). Release or not is a serious question of conservation concern. Wildlife release is spiritually demanding for religious believers, especially Buddhists. However, it is an undeniable fact that millions of animals are traded, killed, transmit diseases and become invasive species due to this practice every year (2-4, 7). This issue occurs on a wide landscape-scale and should be dealt with by both legislation and education with the good participation of government departments, religious, and scientific groups. Legislation is needed for banning 'release wildlife' from trading markets. Religious groups should educate believers not to buy wildlife in the market, and animals health conditions, be it exotic or not, should be assessed by animal experts before any release can happen. Donating money to conservation and animal welfare groups, acting as a volunteer or member in wildlife rescue centers or zoos, releasing rehabilitated animals, and collaborating with conservation and/or scientific bodies should promote good options and alternatives.
REFERENCE AND NOTES
1. A. Benítez-López et al., The impact of hunting on tropical mammal and bird populations. Science 356, 180-183 (2017).
2. L. L. Severinghaus, L. Chi, Prayer animal release in Taiwan. Biological Conservation 89, 301-304 (1999).
3. S. Chan, University of Hong Kong, Pokfulam, Hong Kong (2006).
4. M. Gilbert, C. Sokha, P. H. Joyner, R. L. Thomson, C. Poole, Characterizing the trade of wild birds for merit release in Phnom Penh, Cambodia and associated risks to health and ecology. Biological Conservation 153, 10-16 (2012).
5. X. Liu, M. E. Mcgarrity, Y. Li, The influence of traditional Buddhist wildlife release on biological invasions. Conservation Letters 5, 107–114 (2012).
6. X. Liu, M. E. Mcgarrity, C. Bai, Z. Ke, Y. Li, Ecological knowledge reduces religious release of invasive species. Ecosphere 4, art21 (2013).
7. H. E. McClure, S. Chaiyaphun, The sale of birds at the Bangkok "Sunday Market" Thailand. Natural History Bulletin of the Siam Society 24, 41-78 (1971).
8. S. Schoppe, Science in CITES: The Biology and Ecology of the Southeast Asian Box Turtle (cuora Amboinensis) and it's Uses and Trade in Malaysia. (Petaling Jaya, Selangor, Malaysia, 2008).
9. G. Agoramoorthy, M. J. Hsu, Religious freeing of wildlife promotes alien species invasion. BioScience 55, 6 (2005).
10. A. Ahmed, Live bird trade in Northern India. (TRAFFIC-India, 1997).
11. S. V. Nash, Sold for a song: the trade in southeast Asian non-CITES birds. (TRAFFIC International, Cambridge. 1993).
12. D. S. K. Sharma, Tortoise and Freshwater Turtle Trade and Utilisation in Peninsular Malaysia. ( Petaling Jaya, Selangor, Malaysia, 1999).
13. L. Layton, Songbirds in Singapore: the growth of a pastime. (Oxford University Press, Singapore, 1991).
14. Y. F. Chen, "The practice of releasing prayer animals in Taichung City. Ching-yi Humanity Report " (1995).
15. Y. Xu, B. Zhong, "'Release', why release become kill"in Yangcheng Evening News. (Guangzhou, 2005). http://www.ycwb.com/gb/content/2005-10/10/content_996624.htm (available on 10 May, 2017)