Pangolins, unique scale-covered mammals, are drastically declining in numbers across Asia and Africa, largely due to illegal trade. Part of the trade, both legal and illegal, supports the traditional Chinese medicine market, which has attracted conservation attention. The level of demand for pangolins and other animals in traditional Chinese medicine, however, hasn’t been thoroughly studied.
In a new study published in the journal Nature Conservation, Dr Yifu Wang, currently a postdoc researcher at the University of Hong Kong, investigated pangolin scale trade in China, interviewing staff in hospitals and pharmaceutical shops in two provinces (Henan and Hainan). Between October 2016 and April 2017, she and her team talked to doctors from 41 hospitals and shop owners and assistants from 134 pharmaceutical shops.
The research found pangolin scales and their derivatives were widely available in hospitals and pharmaceutical shops across Henan and Hainan Provinces. The legislation in place, however, has not been able to prevent ongoing illegal trade in pangolin products. Her team found that 46% of surveyed hospitals and 34% of surveyed pharmaceutical shops were selling pangolin scale products illegally.
“Existing legal trade allows 711 hospitals to sell pangolin products as medicine with regulations on manufacturer, package, and national annual sale quantity,” explains Dr Yifu Wang. “However, we show that pangolin scales are under heavy demand and unpermitted sellers are commonly found illegally selling pangolin products.”
“Quantities of products traded by permitted legal sellers are estimated to greatly exceed the supply capacity of legal sources,” she continues.
This widespread illegal trade, coupled with the very limited legal supply capacity compared to market demand, is concerning. The researchers point to the urgent need to reduce demand from traditional Chinese medicine on pangolin scales and revise the current legal pangolin scale trade system.
“We also highlight the importance of incorporating the traditional Chinese medicine sector into combating illegal wildlife trade and species conservation beyond pangolins,” they conclude.
The researchers plan to continue investigating the pangolin scale market in China to understand the trade after COVID-19.
But gene drives are not a one-size-fits-all solution
Invasive alien mammals can have catastrophic impacts on native flora and fauna, causing species extinctions and driving profound environmental change. Classical control methods such as poison baiting, trapping, or hunting are currently not feasible on a large scale, which is why researchers are looking for alternatives.
CRISPR-based genome engineering is often seen as a “silver bullet” for pest control. Despite the increasing interest in the development of this technology for invasive mammals like mice, rats, rabbits, feral cats, and foxes, studies have so far only focused on mice.
Scientists have been pondering whether genome editing technologies could help eradicate larger mammals, and if so, how long it would take.
In order to address these questions, a team of researchers from the University of Adelaide developed a mathematical model able to simulate the impact of gene drives on mammal populations at a landscape scale. Published in the open-access NeoBiotajournal, their study is the first to estimate the time it would take to eradicate long-lived alien mammals.
Using CRISPR-Cas9 technology, the simulated gene drive relies on “molecular scissors” inserted into the Y-chromosome that target and slice up the X-chromosome at the right time during meiosis, so that only Y-chromosome carrying sperms are functional and can successfully fertilize the egg. In this way, the drive carrying males should only produce sons that also carry the molecular scissors on their Y-chromosome. Over multiple generations, females will become rarer and produce fewer offspring; as a result, the population size will fall.
This “X-shredder” drive has been successfully developed and demonstrated to suppress cage populations of malaria-carrying mosquitos, but has not yet been developed in mammals. The model shows that the X-shredder drive could potentially achieve landscape-scale eradication of mice, rats, rabbits, feral cats, and red foxes, but the probability of success and the time it would take to eradicate them vary greatly.
The researchers investigated the ability of the X-shredder drive to eradicate a population of 200,000 individuals of each species. “CRISPR-based gene drives offer novel solutions for controlling invasive alien species, which could ultimately extend eradication efforts to continental scales,” they concluded.
The method could be effective in small-sized pests, such as rodents and rabbits. The expected time to eradication is 18 years for mice, 19 years for rats, and 48 years for rabbits, with 90% population suppression achieved in around half those times.
However, the results suggest that gene drives are not a one-size-fits-all solution: they might not be so useful in larger species like cats and foxes.
“The probability of eradicating feral cats with gene drives is identical to flipping a coin, 50/50; and provided that the coin lands on the right side, it would take about 140 years to get rid of them,” says Dr. Aysegul Birand, part of the research team. “The probability of eradication is higher for foxes, but the wait is even longer.”
You may assume that metropolitan areas are devoid of wildlife, but that is very far from the truth. The remaining green spaces within the urban matrices of large cities can serve as corridors or stepping stones for wild animals. Sometimes, even threatened mammal species end up using them.
On August 12, 2020, a research team from Brazil recorded a South American coati in Canoas, the fourth most populous and densely urbanized city in the southernmost state of Brazil, Rio Grande do Sul. The animal was detected with a camera trap during a Masters research project conducted at the Canoas Airbase, one of the last green spaces remaining in the municipality.
Widely distributed throughout the continent, the South American coati is a medium-sized carnivore living on trees and feeding mainly on small invertebrates and fruits. The species is classified as Vulnerable in Rio Grande do Sul, and it’s considered threatened mainly because of the loss of its forest habitats.
The study that recorded an individual in the urban area was conducted as part of a partnership between the Canoas Airbase and La Salle University. Led by Dr Cristina Vargas Cademartori from La Salle University, the research team was made up of Diego Floriano da Rocha (Doctoral student), Thaís Brauner do Rosario (Masters student), Ana Carolina Pontes Maciel (biologist at the Canoas Airbase), and Duana Suelem Alves (undergraduate student). They described in detail the record and the study area in a paper in the open-access journal Neotropical Biology and Conservation.
The researchers were surprised to find the coati in the midst of a dense urban area. Although the species is not considered threatened in the majority of its area of distribution, its populations have been in decline because of habitat loss and hunting.
“This record confirms the capacity of this species to use environments that have been changed by anthropic activity,” the researchers write in their paper, adding that, because of all the food that humans leave behind, urban environments can in fact favor the establishment of more adaptable species like the coati.
The discovery highlights the importance of urban green spaces for wildlife conservation. “This is very important for defining appropriate conservation measurements for endangered species, especially beyond protected areas,” the authors conclude.
Research article: da Rocha DF, do Rosario TB, Maciel ACP, Alves DS, Cademartori CV (2022) Record of occurrence of Nasua nasua (Linnaeus, 1766) (Carnivora, Procyonidae) in a densely urbanized area of the city of Canoas, southern Brazil. Neotropical Biology and Conservation 17(2): 111-116. https://doi.org/10.3897/neotropical.17.e81824
Lowland tapir populations in the Atlantic Forest in South America are at risk of almost complete disappearance, scientists have estimated. The main long-term threat to their well-being is population isolation, as hunting and highways keep populations away from each other. Urgent measures need to be taken to connect isolated populations and ensure the long-term conservation of tapirs, warn the authors of a new study published in the open-access journal Neotropical Biology and Conservation.
Lowland tapir populations in the Atlantic Forest in South America are at risk of almost complete disappearance, scientists have estimated. Weighing up to 250 kg, the animal can adapt to most habitats in South America—but its populations continue to decline across its range.
Today, its survival is seriously threatened: it can be found in just 1.78% of its original distributional range in the Atlantic Forest biome, which covers parts of Brazil, Argentina and Paraguay. The main long-term threat to its well-being is population isolation, as hunting and highways keep populations away from each other.
Urgent measures need to be taken to connect isolated populations and ensure the long-term conservation of tapirs, warn the authors of a new study on the distribution and conservation status of lowland tapirsin the South American Atlantic Forest, published in the open-access journal Neotropical Biology and Conservation.
“Of the 48 tapir populations identified during the study, between 31.3% and 68.8% are demographically unviable (low number of individuals), and between 70.8% and 93.8% of the populations are genetically unviable (low gene flow). Only 3-14 populations are still viable in the long run when both criteria are considered. The evidence suggests that with the appropriate conservation actions, the lowland tapir could be broadly distributed throughout the Atlantic Forest,” says Kevin Flesher.
“Tapirs have low reproductive potential, including a long reproductive cycle with the birth of just one young after a gestation period of 13-14 months and intervals of up to three years between births. Our populational simulations clearly show how, in the case of small populations, even the loss of a single individual per year can result in rapid extinction of an entire local population,” adds Medici.
Kevin Flesher dedicated 15 years to visiting 93 reserves in the Atlantic Forest, talking to people and analyzing 217 datasets, before he compiled the necessary data to design conservation actions that can ensure the survival of tapirs in the area.
The states of São Paulo and Paraná in Brazil have the largest number of remaining populations: 14 and 10, respectively. The two largest populations are in Misiones, Argentina, and in the neighboring Iguaçu and Turvo reserves, in Paraná and Rio Grande do Sul, Brazil.
“As far as our knowledge goes, there is no evidence of movement of tapirs between these populations,” points out Medici.
The distance between population fragments, however, is not what is stopping them.
“The central problem is the multiple threats they face while crossing the habitat,” explains Flesher. Highways are one major obstacle that limits the access of tapirs to forests with adequate habitat. “For example, the heavy traffic on highway BR-101 (which cuts the Brazilian Atlantic Forest from North to South) is a death trap to wildlife. Tapirs often die when attempting to cross it,” explains Medici.
The construction of highways and expansion of traffic in and around natural areas is a serious threat to large tapir populations that might otherwise have the chance to thrive, like those in Misiones, Argentina, and Serra do Mar, Brazil.
“Roadkill is a significant cause of death in six of the eight reservations in which highways cross tapir populations, and the expansion of the roadway grid in the country threatens to cause population fragmentation in at least four populations,” points out Flesher. This is why finding ways to allow tapirs to cross highways safely is an urgent conservation priority.
The results of the study, however, give cause for “cautious optimism” for the future of tapirs in the area: after decades of dedicated conservation efforts, the situation is starting to improve.
“Despite these continuing challenges for tapir conservation, most populations appear to be stable or increasing and the conservation outlook for the species is better than several decades ago, when the first efforts to protect the species began,” Kevin Flesher concludes.
Flesher KM, Medici EP (2022) The distribution and conservation status of Tapirus terrestris in the South American Atlantic Forest. Neotropical Biology and Conservation 17(1): 1-19.https://doi.org/10.3897/neotropical.17.e71867
Genetic assessment of captive gibbons to identify their species and subspecies is an important step before any conservation actions. A group of wildlife researchers recently discovered a previously unknown population of white-handed gibbons (subspecies lar) from Peninsular Malaysia. Their findings are now published in the open-access journal ZooKeys. Betsy and Lola are among the captive white-handed gibbons undergoing a strict rehabilitation process before being released back to the wild.
Many captive gibbons kept in zoos and rescue centres have been seized from illegal pet trade, private collectors, and plantations where their natural habitats are getting destroyed.
In 2013, the National Wildlife Rescue Centre (NWRC) of the Department of Wildlife and National Parks (PERHILITAN) was established in Peninsular Malaysia to help with the rehabilitation of wildlife species – including gibbons – before they are reintroduced or translocated back to the wild. Under the Primate Rehabilitation Programme initiated by PERHILITAN, captive gibbons have to go through a number of procedures and assessments, where their taxonomy and genetics might be examined, before they can go back to living in the wild.
In a research paper published in the open-access journal ZooKeys, the team describes a previously unknown southern population of the white-handed gibbon subspecies lar living in Peninsular Malaysia. In what started as a straightforward species and subspecies identification process using DNA technology, the researchers discovered unusual mutations in the DNA of the studied gibbons. This is how the researchers found themselves before a distinct population, which they concluded must have been evolving in isolation.
“Given the prolonged isolation, it is likely that the southern population has undergone some local speciation, but this finding should be regarded as preliminary and requires further investigation,” explained Dr Jeffrine. Furthermore, the researchers suggest there might be a northern population inhabiting Southern Thailand.
Still going through rehabilitation, the gibbons from the study have been pre-released into a semi-wild enclosure known as Pulau Ungka (Gibbon Island), where their recovery is closely monitored by primate experts of PERHILITAN.
Gani M, Rovie-Ryan JJ, Sitam FT, Mohd Kulaimi, NA, Zheng, CC, Atiqah AN, Abd Rahim, NM, Mohammed AA (2021) Taxonomic and genetic assessment of captive White-Handed Gibbons (Hylobates lar) in Peninsular Malaysia with implications towards conservation translocation and reintroduction programme. ZooKeys 1076: 25–41 (2021), doi: 10.3897/zookeys.1076.73262
Revolutionary environmental DNA analysis holds great potential for the future of biodiversity monitoring, concludes a new study
In times of exacerbating biodiversity loss, reliable data on species occurrence are essential, in order for prompt and adequate conservation actions to be initiated. This is especially true for freshwater ecosystems, which are particularly vulnerable and threatened by anthropogenic impacts. Their ecological status has already been highlighted as a top priority by multiple national and international directives, such as the European Water Framework Directive.
However, traditional monitoring methods, such as electrofishing, trapping methods, or observation-based assessments, which are the current status-quo in fish monitoring, are often time- and cost-consuming. As a result, over the last decade, scientists progressively agree that we need a more comprehensive and holistic method to assess freshwater biodiversity.
Meanwhile, recent studies have continuously been demonstrating that eDNA metabarcoding analyses, where DNA traces found in the water are used to identify what organisms live there, is an efficient method to capture aquatic biodiversity in a fast, reliable, non-invasive and relatively low-cost manner. In such metabarcoding studies, scientists sample, collect and sequence DNA, so that they can compare it with existing databases and identify the source organisms.
Furthermore, as eDNA metabarcoding assessments use samples from water, often streams, located at the lowest point, one such sample usually contains not only traces of specimens that come into direct contact with water, for example, by swimming or drinking, but also collects traces of terrestrial species indirectly via rainfalls, snowmelt, groundwaters etc.
In standard fish eDNA metabarcoding assessments, these ‘bycatch data’ are typically left aside. Yet, from a viewpoint of a more holistic biodiversity monitoring, they hold immense potential to also detect the presence of terrestrial and semi-terrestrial species in the catchment.
In fact, it took only one day for the team, led by Till-Hendrik Macher, PhD student in the German Federal Environmental Agency-funded GeDNA project, to collect the samples. Using metabarcoding to analyse the DNA from the samples, the researchers identified as much as 50% of the fishes, 22% of the mammal species, and 7.4% of the breeding bird species in the region.
However, the team also concluded that while it would normally take only 10 litres of water to assess the aquatic and semi-terrestrial fauna, terrestrial species required significantly more sampling.
Unlocking data from the increasingly available fish eDNA metabarcoding information enables synergies among terrestrial and aquatic biodiversity monitoring programs, adding further important information on species diversity in space and time.
Macher T-H, Schütz R, Arle J, Beermann AJ, Koschorreck J, Leese F (2021) Beyond fish eDNA metabarcoding: Field replicates disproportionately improve the detection of stream associated vertebrate species. Metabarcoding and Metagenomics 5: e66557. https://doi.org/10.3897/mbmg.5.66557
The recognition of the “Ceguaca, la Mujer de los Juncos” locality comes as a result of research work – published last year in Subterranean Biology – which produced the first checklist of bats for Santa Bárbara
Guest blog post by Eduardo Javier Ordoñez-Trejo and Manfredo Alejandro Turcios-Casco
Bat populations are threatened due to fragmentation and loss of their habitats. Meanwhile, dry forests are some of the least studied and most threatened ecosystems in Honduras, and similarly, so have been the caves.
Caves are important reservoirs of species, as they offer perks no other habitat can provide at once: a refuge from predators, inconstant weather, and a critical venue for social interactions, reproduction, hibernation, roosting and nutrients. In order to protect bat populations, the Latin American and Caribbean Web for Bat Conservation (RELCOM) supports the establishment of Areas of Importance for the Conservation of Bats, abbreviated as AICOMS (Spanish for Areas with Importance for the Conservation of Bats) .
Together with biologists of the National Autonomous University of Honduras (UNAH) and local community members, we provided the first ever checklist of bat species in the Dry Forest of Ceguaca, Santa Barbara (Honduras), and described the importance of two caves in the area for bat conservation based on species richness. We published this study last June in Subterranean Biology.
We found that caves in Ceguaca are inhabited by at least 23 bat species of four families, which represents approximately a fifth of all species known from Honduras. Their inhabitants include several threatened species like the hairy-legged vampire bat (Diphylla ecaudata), one of the three existing vampire bats, and rare species with few official records in the area, such as Schmidts’s big-eared bat (Micronycteris schmidtorum). These caves may also represent a critical site for roosting and nursing. During our study, we managed to record pregnant and lactating females of several species, as well as reproductive males.
“It feels wonderful to see that our work has had great results and that with our efforts, we established an area where bats will be protected and studied. This certification also includes the name of Roberto Castellano, an elder member of the community of Ceguaca, who helped us during the fieldwork as our guide. He was a great conservationist of this area and protector of the caves. Unfortunately, he passed away during the study, however, due to his enormous contribution, we dedicated our article to him and included him as part of this AICOM success.”
José Alejandro Soler Orellana, co-author of the study.
Using what we learned in Ceguaca’s caves, we approached the Program for Bat Conservation of Honduras (PCMH) and showed them the evidence the locality was indeed a precious place with a spectacular bat diversity. Consequently, thanks to our collaboration with the PCMH, the site was effectively declared as an Area of Importance for the Conservation of Bats by RELCOM on 6th March 2020.
This is an enormous step for bat conservation in the country. Bat conservation efforts should focus on studying and protecting these and other important habitats. We also need to make sure that local people appreciate the important role the bats play in the ecosystem.
Turcios-Casco MA, Mazier DIO, Orellana JAS, Ávila-Palma HD, Trejo EJO (2019) Two caves in western Honduras are important for bat conservation: first checklist of bats in Santa Bárbara. Subterranean Biology 30: 41–55. https://doi.org/10.3897/subtbiol.30.35420
Described in 1981, the genus Biswamoyopterus is regarded as the most mysterious and rarest amongst all flying squirrels. It comprises two large (1.4-1.8 kg) species endemic to southern Asia: the Namdapha flying squirrel (India) and the Laotian giant flying squirrel (Lao PDR). Each is only known from a single specimen discovered in 1981 and 2013, respectively.
However, a closer look at the specimen from KIZ made it clear that the squirrel exhibited a colouration, as well as skull and teeth anatomy, distinct from any of the previously known species in the genus.
Subsequently, joined by his colleagues from China (Xuelong Jiang, Xueyou Li, Fei Li, Ming Jiang, Wei Zhao and Wenyu Song) and Stephen Jackson from Australia, the team of Quan Li conducted a new field survey. Thus, they successfully obtained another specimen and, additionally, recorded observations of two other flying squirrels. As a result, they included a third member to the enigmatic genus: Biswamoyopterus gaoligongensis, also referred to as the Mount Gaoligong flying squirrel. This new to science species was described in a paperpublished in the open-access journal ZooKeys.
“The morphological features of B. gaoligongensis are closer to the critically endangered and missing Namdapha flying squirrel, but is still readily identifiable as a distinct species,” explains Quan Li.
“The new species was discovered in the ‘blank area’ spanning 1,250 km between the isolated habitats of the two known species, which suggests that the genus is much more widespread than previously thought. There is still hope for new Biswamoyopterus populations to be discovered in between or right next to the already known localities,” he says.
As for the conservation status of the newly described species, the researchers note that it inhabits low-altitude forests which are in close proximity to nearby human settlements. Thereby, they are vulnerable to anthropogenic threats, such as agricultural reclamation and poaching.
“Therefore, there is an urgent need to study the ecology, distribution, and conservation status of this rare and very beautiful genus,” concludes the lead author.
Li Q, Li X-Y, Jackson SM, Li F, Jiang M, Zhao W, Song W-Y, Jiang X-Y (2019) Discovery and description of a mysterious Asian flying squirrel (Rodentia, Sciuridae, Biswamoyopterus) from Mount Gaoligong, southwest China. ZooKeys 864: 147-160. https://doi.org/10.3897/zookeys.864.33678
Modern open-source software helped the researchers identify the male that killed a female and her two cubs
Scientists used a technology designed for the purposes of human forensics, to provide the first genetically documented case of infanticide in brown bears, following the murder of a female and her two cubs in Trentino, the Italian Alps, where a small re-introduced population has been genetically monitored for already 20 years.
To secure their own reproduction, males of some social mammalian species, such as lions and bears, exhibit infanticidal behaviour where they kill the offspring of their competitors, so that they can mate with the females which become fertile again soon after they lose their cubs. However, sometimes females are also killed while trying to protect their young, resulting in a survival threat to small populations and endangered species.
“In isolated populations with a small number of reproductive adults, sexually selected infanticide can negatively impact the long-term conservation of the species, especially in the case where the female is killed while protecting her cubs,” point out the researchers.
“Taking this into account, the genetic identification of the perpetrators could give concrete indications for the management of small populations, for example, placing radio-collars on infanticidal males to track them,” they add. “Nevertheless, genetic studies for identifying infanticidal males have received little attention.”
Thanks to a database containing the genotypes of all bears known to inhabit the study site and an open-source software used to analyse human forensic genetic profiles, the scientists were able to solve the case much like in a television crime series.
Upon finding the three corpses, the researchers were certain that the animals had not been killed by a human. In the beginning, the suspects were all male brown bears reported from the area in 2015.
Hoping to isolate the DNA of the perpetrator, the researchers collected three samples of hairs and swabbed the female’s wounds in search for saliva. Dealing with a relatively small population, the scientists expected that the animals would share a genotype to an extent, meaning they needed plenty of samples.
However, while the DNA retrieved from the saliva swabs did point to an adult male, at first glance it seemed that it belonged to the cubs’ father. Later, the scientists puzzled out that the attacker must have injured the cubs and the mother alternately, thus spreading blood containing the inherited genetic material from the father bear. Previous knowledge also excluded the father, since there are no known cases of male bears killing their offspring. In fact, they seem to distinguish their own younglings, even though they most likely recognise the mother.
To successfully determine the attacker, the scientists had to use the very small amount of genetic material from the saliva swabs they managed to collect and conduct a highly sophisticated analysis, in order to obtain four genetic profiles largely overlapping with each other. Then, they compared them against each of the males reported from the area that year. Eventually, they narrowed down the options to an individual listed as M7.
“The monitoring of litters is a fundamental tool for the management of bear populations: it has allowed the authors to genetically confirm the existence of cases of infanticide and in the future may facilitate the retrieval of information necessary to assess the impact of SSI on demographic trends,” conclude the researchers.
Davoli F, Cozzo M, Angeli F, Groff C, Randi E (2018) Infanticide in brown bear: a case-study in the Italian Alps – Genetic identification of perpetrator and implications in small populations. Nature Conservation 25: 55-75. https://doi.org/10.3897/natureconservation.25.23776
Much like gym enthusiasts, every year Asiatic black bears seem to be on the lookout for protein-rich food ahead of the summer, so that they can bulk up on lean muscle mass in place of the fat tissue formed last year prior to hibernation. This was concluded in a study by Dr. Shino Furusaka, Tokyo University of Agriculture and Technology and his team, based on direct observations on bears living across an area of about 60 km2 in Japan. The study is published in the open access journal ZooKeys.
In order to determine the bears’ food preferences and habits, the scientists followed a large number of animals in the Ashio area of the Ashio-Nikko Mountains in Japan from April to July in both 2013 and 2014. To avoid unnecessary intrusion, they stayed at a distance of at least 200 metres using video cameras with telescopic lenses to document the sightings. Having documented the plant species the bears consumed, the researchers studied their nutritional content and made conclusions about the nutrients needed for the species after hibernation.
While heavily dependent on food availability, generally the bears were noted to prefer food which is high in protein, but poor in fibre — likely because their stomachs and intestines were unable to efficiently digest the latter. Furthermore, the protein-rich diet ensures that the muscle mass is rebuilt to replace the lost winter fat.
Interestingly, the bears were observed to change their food preferences as spring progressed and that seemed to be linked to the shifts in the nutritional value of the available food.
Starting with their observations at the beginning of April, the scientists did not record any feeding behaviour until the end of the month. As leaf flush was yet to occur, the animals were active and feeding on overwintered grass. However, in early May, the bears began consuming newly emerged leaves, grass and, later in the month, they added flowers to their menu.
A shift in behaviour occurred in the following months. In June and July, the bears were seen to feed mainly on ants, with a small portion of their food intake consisting of grasses, sika deer carcasses and bees. Curiously, when the scientists looked into the nutritional content of the same plants which the animals sought only a few weeks ago, they found out that now they were significantly poorer in protein and richer in fibre.
Another finding showed that the calories in the different items were not related to the choice of food which likely proves that the key factor is none other than the amount of protein, provided that the fibre value is low enough for good digestibility.
Understanding the food preferences and habits of animals, as well as the reasons behind them, is essential for the development and revision of habitat management plans. However, previous knowledge of the feeding behaviour of Asiatic black bears has been based solely on faecal analyses which has not provided sufficient details on which nutritional factors influence the use of particular foods.
Furusaka S, Kozakai C, Nemoto Y, Umemura Y, Naganuma T, Yamazaki K, Koike S (2017) The selection by the Asiatic black bear (Ursus thibetanus) of spring plant food items according to their nutritional values. ZooKeys 672: 121-133. https://doi.org/10.3897/zookeys.672.10078