LAGOMORPH CONSERVATION IMPLEMENTATION
RABBIT HEMORRHAGIC DISEASE VIRUS TYPE 2 (RHDV-2) INFECTS WILD LAGOMORPHS IN WESTERN NORTH AMERICA
Rabbit Hemorrhagic Disease Virus type 2 (RHDV-2) has been diagnosed in both wild jackrabbits and cottontail rabbits in the southwestern United States (Texas, New Mexico, Arizona, Colorado, Utah and California) and northern Mexico (including the Baja California Peninsula) beginning in spring 2020. The virus has also been found in captive populations of domestic lagomorphs throughout this range. Massive die-offs of lagomorphs have been recorded in some locations, although many populations have not yet been affected (we fear that this may just be a matter of time). Infected lagomorphs may experience lethargy, a high fever, or difficulty breathing – or they may exhibit no symptoms at all. However, mortality rate can reach 100 percent.
Origin of the RHDV strain is unclear – it was first detected in domestic rabbits in China, although most consider it to be native to Europe. RHDV was introduced into Australia (1995) and New Zealand (1997) to control invasive rabbits. Subsequently the variant RHDV-2 appeared in France in 2010, after which it became the prevalent strain in Europe where it spread rapidly and caused significant losses in wild and farmed rabbits. In North America RHDV-2 first appeared in domestic rabbits in British Columbia, then in Washington State and New York. Since the first detection of RHDV-2 in the United States, it took only two years to jump into wild American lagomorph species. There is no evidence of any intentional releases of RHDV-2, and its rapid spread appears to be due to the movement of farmed or other domesticated rabbits.
Lagomorphs represent a key component of native ecosystems, and the potential widespread loss of lagomorphs in a region is cause for serious concern about the knock-on effects on their predators. Additionally, several species and subspecies of lagomorphs in North America (Sylvilagus transitionalis, S. bachmani riparius, Lepus insularis, etc.) are of conservation concern – and the virus could lead to their extinction.
IUCN SSC LEADER'S MEETING
LSG Co-chairs Hayley Lanier and Andrew Smith were honored to attend the 4th IUCN SSC Leaders’ Meeting in Abu Dhabi in early October. This event, sponsored by the Environment Agency of Abu Dhabi, represents an opportunity for all leaders across the Species Survival Commission to liaise, compare notes, and plan to make the commission stronger and to better conserve our world’s biological diversity. The meeting was led by SSC Chair Jon Paul Rodriguez, and bought together more than 300 chairs and co-chairs of SSC specialist groups, specialist group Red List Authority coordinators, and staff from the SSC Chair’s office, the IUCN Global Species Program, and the IUCN/SSC Red List office.
With over 9000 volunteer members in over 130 specialist groups, the Species Survival Commission is the largest in the commission portfolio of IUCN. With its size come incredible challenges including how to manage such a large volunteer conservation force, how to fund activities, how to coordinate activities within and among specialist groups, and how to coordinate our collective efforts with the mission and goals of IUCN. Because specialist group chairs (and the members of specialist groups) are spread around the earth, understanding and overcoming these challenges is not easy – even in a world with enhanced electronic communication ability. Meeting in person with the opportunity for open discussion and give-and-take is essential, and thus the need for such a meeting. The daily plenary sessions and afternoon thematic and taxonomic break-out sessions allowed for productive interactions. Andrew was given the opportunity in the initial plenary session to highlight some of the terrific conservation projects undertaken by LSG members, and in the concluding awards ceremony – as a tribute to all the great work that each member has contributed – the LSG was presented one of the SSC Chair’s Citation of Excellence.
The meeting concluded with the roll-out of the Abu Dhabi Call for Global Species Conservation Action.
NORTH AMERICAN LAGOMORPHS
LSG member David Brown has been very active recently investigating the status of rabbits and hares, primarily across western North America. Along with LSG co-chair Andrew Smith, Brown has determined that both cottontail and jackrabbit numbers appear to have declined in most areas in the western US during the past 50 years, with the largest decreases in California, the Great Basin, and mid-central plains states. A detailed examination of the distribution and abundance of white-tailed jackrabbits (Lepus townsendii), currently in review, shows a similar trend of decline since 1950. The white-tailed jackrabbit is now thought to be extirpated in British Columbia, Illinois, Kansas, Missouri, Oklahoma and Wisconsin, and close to extirpation in Iowa. It is greatly reduced in distribution and abundance in Minnesota, Nebraska, Washington, and Ontario. Its numbers are in a downward trend in California, Colorado, Nevada, and South Dakota. The only populations that have not generated concern occur in the northern states of Idaho, Montana, and North Dakota along with the provinces of Alberta, Manitoba, and Saskatchewan.
Brown has formed a “Jackrabbit Working Group” along with biologists from the Arizona Game and Fish Department, and they have conducted a series of investigations on the antelope jackrabbit (L. alleni) at the north-western edge of its range. They have determined that the antelope jackrabbit undergoes population fluctuations, not in concordance with changes in precipitation, but possibly due to variability in predation levels. Working with LSG member Consuelo Lorenzo, Brown has also published a needed review of the distribution, status, and conservation needs of the poorly-known white-sided jackrabbit (L. callotis).
Brown has also recently reinstated the species status of the Tamaulipas white-sided jackrabbit (L. altimirae) from eastern Mexico, placing it alongside other white-sided jackrabbits (L. favigularis, L. callotis, L. alleni), and removing it as a subspecies of the black-tailed jackrabbit (L. californicus).
THE AMAMI RABBIT – JAPAN
The Endangered (EN) Amami Rabbit (Pentalagus furnessi) occurs only on Amami-oshima Island (712 km2) and on Tokuno-shima Island (248 km2) in the Ryukyu Archipelago in southwestern Japan. It is the only all black rabbit in the world. Conservation of the Amami Rabbit has been led by LSG member Fumio Yamada.
The impact of habitat loss is severe for the Amami Rabbit because extensive logging operations on the two islands have reduced old forest habitat occupied by the rabbit to less than 10% - 30% of their extent in 1980. The rabbit has also been heavily impacted by invasive species such as the Small Indian Mongoose (Herpestes auropunctatus) on Amami-oshima Island. To counteract this threat an eradication program was enacted by the Ministry of the Environment in Japan in 2005. The program has been a success, with the captured number of mongoose declining from 2,600 in 2005 to 10 in 2017, and the estimated mongoose population also declined from 10,000 in 2005 to less than 50 in 2017. The Amami Rabbit as well as other small mammals and amphibians have recovered dramatically.
Now there is another threat facing the Amami Rabbit – predation by feral cats. In response, feral cat control has been implemented on Tokuno-shima Island. Following consensus building of the feral cat control program on Amami-oshima Island, control was re-started in 2018 and the recovery of the rabbits is being monitored.
The Amami Rabbit is an important conservation species, providing value to the nomination by the Japanese government for Amami-oshima and Tokuno-shima islands, along with the northern part of Okinawa Island and Iriomote Island, to achieve World Natural Heritage Site status.
NEW RIVERINE RABBIT POPULATION FOUND IN SOUTH AFRICA
The Endangered Wildlife Trust’s Drylands Conservation Programme was thrilled to confirm the presence of a population of Riverine Rabbits (Bunolagus monticularis - CR Critically Endangered) on the western side of the Baviaanskloof, South Africa, in late May 2019. This population represents a completely new distribution of the species not anticipated by any previous population modelling. According to Bonnie Schumann, EWT Nama Karoo Coordinator, this is an historic find with the closest confirmed sightings of the southern population having been more than 250 km to the west.
The discovery comes after ornithologist and well-known conservation scientist, Alan Lee from Blue Hills Escape Farm in the Western Cape, discovered a dead Riverine Rabbit on a gravel road in December 2018. Fortunately, he realized that the animal in front of him was not a hare or a Rock Rabbit but the Critically Endangered Riverine Rabbit.
EWT team members visited the area and set out 38 camera traps with the aim of capturing live images to confirm the presence of another population. Camera traps are placed in clusters and in such a manner that individuals are not likely to be observed twice by more than one cluster. After 50 days in the field, the cameras were collected by the team and processed.
According to Cobus Theron, EWT Drylands Conservation Programme Manager and member of the IUCN SSC Lagomorph Specialist Group, “while we expected one or two clusters to capture images, we were astounded that eight of our 12 clusters had confirmed images of Riverine Rabbits on them!” This again demonstrates that this species is the true hide-and-seek champion of the Karoo.
“This find is unexpected and redefines our understanding of the distribution of the species. It demonstrates that their elusiveness is part of their survival strategy,” continues Cobus.
CapeNature Executive Director: Biodiversity Capabilities, Coral Birss, added, “CapeNature is delighted about the recent discovery of Riverine Rabbits in the Baviaanskloof area in the Southern Cape. The species, which previously managed to go virtually undetected, has proven to effectively solidify its presence, supported by research on genetic connectivity and distribution in the last decade. This latest discovery is remarkable and bodes well for the future survival of this Critically Endangered species, particularly for its protection within the landscapes of the Western Cape surrounding our nature reserves. CapeNature commends the great work and research being done and facilitated by the Endangered Wildlife Trust and looks forward to further collaboration and tracking the progress of this interesting species.”
The EWT has also obtained a genetic sample from the dead rabbit found by Alan Lee. This will be analyzed to provide insights into the relationship between the Baviaanskloof Riverine Rabbits and Riverine Rabbits from the northern and southern populations.
The find shows the importance of sightings by members of the public and the value of social media in connecting people. The EWT, along with CapeNature, will now incorporate the findings into their conservation strategy and engage landowners in the Baviaanskloof to ensure that the Riverine Rabbit receives the attention it deserves.
COLUMBIA BASIN PYGMY RABBIT REINTRODUCTION
The LSG team of Lisa Shipley, Penny Becker and Janet Rachlow have engaged in several far-ranging studies on the ecology and behavior of the Pygmy Rabbit (Brachylagus idahoensis). The Pygmy Rabbit is a denizen of high sagebrush habitat throughout the northwestern United States. One isolated and genetically distinct population in the Columbia Basin of central Washington State began declining drastically in range and abundance in the 1990s and was listed as Endangered as a Distinct Population Segment under the US Endangered Species Act in 2001. Captive breeding began in 2001 with 16 adult animals, after which the wild population was extirpated by 2003. Captive breeding produced > 1000 kits, but high levels of mortality from disease and inbreeding failed to produce enough surplus animals for sustained reintroduction. Ultimately, captive-bred rabbits and wild-caught rabbits from the core of the species range were placed in large in situ field enclosures to produce surplus animals for releases beginning in 2012.
As of 2018, Pygmy Rabbits have been re-established in the Columbia Basin in three non-connected locations within suitable deep soil sagebrush habitat in historically occupied sites. The population established in 2012 contains an estimated minimum of 200 rabbits, and two newly-established sites currently support fewer than 10 rabbits each. These populations contain 22% Columbia Basin ancestry, with remaining genetic contributions from other parts of the Pygmy Rabbit’s range. From 2011 – 2016, 1782 juveniles and 165 adults were released from onsite captive pens into the wild, and in 2017, 98% of rabbits detected in the wild were wild born. Ongoing management activities include on-site semi-wild captive breeding, translocation of wild kits with soft-release, annual transects for burrows and scat to document distribution, and non-invasive genetic sampling.
THE PLATEAU PIKA IS AN ECOSYSTEM ENGINEER AND A KEYSTONE SPECIES
LSG Co-Chair Andrew Smith has been investigating the ecology of the Plateau Pika (Ochotona curzoniae) since 1984. His work has helped clarify the important ecological role that this species plays across the Qinghai-Tibetan Plateau (QTP). The Plateau Pika is a burrowing species that occupies open meadow grassland habitat where it lives in highly social family groups. Because it can attain high densities, authorities have branded it as a pest, and for several decades the species has been poisoned across hundreds of thousands of kilometers, including in the Sanjianyuan National Nature Reserve. In opposition to this view, Smith’s research has shown that the Plateau Pika is an important ecosystem engineer and a keystone species for biodiversity on the QTP:
Most of the native small birds on the QTP nest in pika burrows; when pikas are poisoned, their burrows collapse, and these species disappear;
The pika is the primary food source for nearly every predatory bird and mammal on the QTP; when pikas are poisoned they lose this food source and their populations greatly suffer;
The burrowing by pikas cuts through the thick vegetative mat on the plateau, thus is responsible for recycling nutrients to the surface and creating habitat leading to increased plant species richness in non-poisoned areas compared with poisoned areas;
The burrowing by pikas increases infiltration rates of water during the summer monsoon rainstorms, thus minimizing local erosion and even downstream flooding; increased potential for flooding from poisoned areas can contribute to significant damage and loss of life in lowland areas in China.
As a result of Smith’s work, there is now increased attention being paid to the Plateau Pika, and an indication that some of the poisoning has stopped. A recent China Global Television Network story was entitled: “A Late Apology to the Plateau Pika.”
PIKA FAN CLUB – JAPAN
The Pika Fan Club was founded in 1995 by LSG member Toshimi Ichikawa and others to protect the habitat of the northern pika in Hokkaido. The club currently has 3341 members, making it one of the largest green groups in Japan. The goals of the PFC include making the pika a Japanese natural monument (because the habitat of wildlife designated as a national natural monument is protected by law in Japan), protecting the habitat of pikas from development , and educating and enlightening the general public about the natural history and ecology of pikas.
The PFC has been a powerful force leading to the curtailment of several major construction (largely road construction) projects that would have impacted the habitat of pikas (1999: “Shihoro Kogen Doro” in Daisetsuzan National Park; 2003: “Hidaka Odan Doro”; 2010: “Daikibo Rindo”).
Educational outreach by the PFC includes publication of two books: “We want to hear pika calling - a tale of hard struggle of one small NGO” (1999), and “Ezonakiusagi (Ochotona hyperborea yesoensis) - pikas in the rocks” (a photo book; 2017). They also hold frequent public meetings throughout Japan.