Have you heard of the Kihansi spray toad? I’ve got a trip to New York planned this summer, and seeing these cute little guys is now at the top of my list of things to do.

…And New York is pretty much the only place in the world you can see them now, sadly. They’re extinct in the wild, which is unsurprising considering their native habitat is made up of just two hectares along the Kihansi Gorge in Tanzania. When a dam blocked 90% of the water flow to their waterfall habitat, the Kihansi toad population crashed. An outbreak of the amphibian dread-disease chytrid fungus cut the remaining population down to critical numbers, prompting the Wildlife Conservation Society to swoop in and rescue 499 of the tiny toads and whisk them back to the Bronx.

Although some of the toads were sent to five different zoos in the US, only the Bronx Zoo and the Toledo Zoo managed to keep them alive. As it turns out, evolving in such a specific area left the toads with very specialized needs, and the zoo has set up pure mist sprayers from filtered water, halogen lamps, and disease-free specially-bred insects for food. Now that they’re able to keep the toads alive and breed them successfully in captivity, WCS is working towards a re-introduction plan that involves an artificial mist system and the eradication of invasive plant species.

For now though, you can see them at the new World of Reptiles exhibit at the Bronx Zoo. Kihansi spray toads are unusual, charismatic amphibians — mustard yellow in color, and tiny enough to sit on the face of a dime. Unlike most amphibians, they also give birth to tiny, purple-ish live young, small enough to sit on the head of a pin.

If that’s not a poster child of cuteness for conservation, I don’t know what is.

Four of the world’s remaining eight Northern white rhinos (Ceratotherium simum cottoni) are settling in to their new home in the Ol Pejeta reserve in Kenya. They were shipped to the reserve from Dvůr Králové zoo in the Czech Republic, where they’ve been for the past 30 years. The two remaining Czech Northern white rhinos and two Northern white rhinos at the Wild Animal Park, in San Diego, aren’t reproductively viable, so the four now in Kenya are the last hope of continuing the genetic line.

The Northern white rhino has a sad history. From the 1970s to the 1980s, their population was reduced to 15 due to poaching. Earlier in this decade, that population had doubled and seemed to be on the slow road to recovery. Since 2003, though, the last remaining Northern whites were killed and the species has been extinct in the wild until this week’s transfer. At this point, the goal is merely to pass on as much of the subspecies’ lineage as possible. Rob Brett, director of Flora and Fauna International, acknowledges that inter-breeding with Southern white rhinos in Kenya is “inevitable”.

Northern white rhino

Whether or not they will even be able to breed is still up for debate. San Diego Wild Animal Park mammal curator Randy Rieches contends that there is no chance of breeding in the herd, due to reproductive pathologies that set in after a period of reproductive dormancy. On the other hand, Dana Holeckova, director of the Dvůr Králové zoo, said at the time of the transfer, “I feel so happy. It’s my birthday today and this is like a gift to Africa. There is a 90 percent chance they will reproduce and I hope that we will start a new group of Northern White rhinos in Africa.” Clearly, the jury is still out on the rhinos’ fate, and only time will tell.

Northern white rhino

The money for the transfer was supplied by Alastair Lucas, vice chairman of Goldman Sachs in Australia, explicitly for the purpose of relocating these rhinos.

A new scientific survey has identified a huge nesting population of leatherback sea turtles in Gabon, West Africa. Science Daily reports on the article in press in this month’s issue of Biological Conservation, the new population may include as many as 41,000 female leatherbacks.

Leatherback sea turtles are classified as critically endangered, and the most recent survey in 1996 found only an estimated 20,000 to 30,000 adult females. The Gabon population could nearly double current population estimates, and may change the turtles’ IUCN listing.

Unlike other sea turtles, leatherbacks have a soft outer shell made from numerous small bones covered with leathery skin, rather than a hard outer shell. They can weigh up to a ton, measuring eight feet in length. Leatherback populations have been found all over the world, in the Atlantic, Pacific, and Indian oceans as far north as British Columbia, and as far south as the Cape of Good Hope. The Gabon population is by far the largest currently identified. 79% of the nesting sites in the study are located in protected areas, and one of the authors, Dr. Angela Formia of the Wildlife Conservation Society, said:

These findings show the critical importance of protected areas to maintain populations of sea turtles. Gabon should be commended for creating a network of National Parks in 2002 that have provided a sanctuary for this endangered species as well as other rare wildlife.

Matthew J. Witt, Bruno Baert, Annette C. Broderick, Angela Formia, Jacques Fretey, Alain Gibudi, Carine Moussounda, Gil Avery Mounguengui Mounguengui, Solange Ngouessono, Richard J. Parnell, Dominique Roumet, Guy-Philippe Sounguet, Bas Verhage, Alex Zogo, Brendan J. Godley. Aerial surveying of the world’s largest leatherback turtle rookery: A more effective methodology for large-scale monitoring. Biological Conservation, 2009; DOI: 10.1016/j.biocon.2009.03.009

Science Daily: World’s Largest Leatherback Turtle Population Found.

The latest survey of bird species has been completed by BirdLife International for the IUCN Red List, and despite worldwide conservation efforts, more birds are endangered now than ever before. According to their survey, 1,227 species (12 percent) are classified as globally threatened with extinction. The IUCN Red List now lists 192 species of bird as Critically Endangered, which is the highest threat category.

A recently discovered species from Colombia, the Gorgeted Puffleg (Eriocnemis isabellae), appears for the first time on the IUCN Red List, classified as Critically Endangered. The puffleg, a flamboyantly coloured hummingbird, only has 1,200 hectares of habitat remaining in the cloud forests of the Pinche mountain range in south-west Colombia and eight percent of this is being damaged every year to grow coca.

That’s a photo of the Gorgeted Puffleg. Sadly, that’s probably all most of us will ever see of them, unless part of the population is brought in for a captive breeding program. I’ll try not to be too much of a downer, though. There’s some good news!

In Brazil, Lear’s Macaw (Anodorhynchus leari) has been moved from Critically Endangered to Endangered. Named after the English poet, this spectacular blue parrot has increased four-fold in numbers as a result of a joint effort of many national and international non-governmental organizations, the Brazilian government and local landowners

Beautiful, aren’t they? These Lear’s macaws are at risk of smuggling and poaching, but international protections and careful surveillance of their nesting areas have helped to reduce threats. Other species, such as the Chatham Petrel (Pterodroma axillaris) and Mauritius Fody (Foudia rubra) have also been rescued from the brink of extinction by conservation efforts. No new extinctions were reported.

IUCN – More Critically Endangered birds on IUCN Red List than ever.

This article came out last month, but it’s taken me this long to find time to read it, and to do the necessary background reading to write up a post about it. This article in PLoS ONE describes a study done in 2006 by French scientists to determine whether or not people actually value rare things more than common things. The study was intended as a follow-up to an earlier article in PLoS Biology about the anthropogenic Allee effect, which accepted the theory that humans do value rare things, and as a result participate in various activities based on perceived rarity that contribute to population declines.

Over on the Guilty Planet blog, two of these “do people value rare things” studies, including the PLoS One study, are described. In one study, people at upscale hotels and suburban grocery stores chose between “rare” and “common” sturgeon caviar, which were actually identical species of farmed sturgeon. The “rare” sample was overwhelmingly preferred. The other study measured clicks on a website for slide shows of rare species and common species, the duration of time people were willing to wait for the slide shows to load, and the number of times they tried to re-load them. The study found that people attempted to access the rare species slide show by a significant majority, and were willing to wait longer for it to load.

Personally, I don’t find this terribly interesting. It’s nice to have an empirical basis for the assumption that people value rare things, I suppose, but it seems obvious enough that empirical study wasn’t actually necessary. However, I did find the initial study defining the anthropogenic Allee effect to be fascinating.

The Allee effect is an established effect important to ecology and applied conservation biology which describes the relationship between reproduction capability and population sustainability as population density of species declines. The authors of the PLoS Biology study coined the term “anthropogenic Allee effect” (AAE) to describe a purely artificial Allee effect generated by human activity relating to the “paradox of value” of supposedly rare species of plants and animals. As rarity increases, so does the price people are willing to pay for access to these rare species.

Human activities that can cause an AAE are:

  • Collections, where naturalists, collectors, scientists all work harder and pay more for specimens of increasingly rare species in an attempt to find them before they become extinct;
  • Trophy hunting, as hunters will pay more for the prestige of trophies of rare and restricted species, which may in turn drive up illegal poaching;
  • Luxury items, such as caviar and abalone, which have inflated prices for rare species;
  • Exotic pets, which includes both illegal trading and smuggling, as well as the extreme, exponential increase in prices for some species when endangered species protection is under consideration, before such protections are actually in place — one striking example is that of the turtle Chelodina mccordi , which gained recognition in the pet trade after being described in scientific literature and is now nearly extinct in the wild;
  • Traditional medicine, which prefers rare species over common ones, and is a driving force behind poaching of many species such as tigers and rhinos, and;
  • Ecotourism, when the influx of tourists to an area of significance for species can exert enough stress to cause declines in populations, thus increasing scarcity and driving still more tourism, in a feedback loop sure to spell disaster unless tourism is curbed or capped (such as tourist limitations imposed in the Galapagos).
24 hour armed guard over rhinos in a Zambian park

24 hour armed guard over rhinos in a Zambian park

Such human activities can have extensive impacts on rare and endangered species, even when they’re driven by concern and compassion for biodiversity, as in the case of ecotourism. Decisions to list species as endangered and to supply them with legal protection need to be carefully weighed against our ability to enforce these protections and suppress illegal trade driven by a renewed awareness of their rarity outside the conservation community. While conservationists can play to humans’ love of rare things as a way to generate interest in their plight, that must be carefully weighed against the possibility of creating an AAE and risking further exploitation.

Humans Love Rare Things; Albinos Safe, Endangered Species Screwed : Guilty Planet.

PLoS ONE: Rare Species Are Valued Big Time.

PLoS Biology: Rarity Value and Species Extinction: The Anthropogenic Allee Effect.

EcoWorldy has a great article listing 11 extinct animals that were, amazingly, photographed before they went extinct. Some of the photographs are notably better than others, but they’re all wonderful and heartbreaking. I’m struck by how many of these animals were killed at the hands of humans, either through ruthless hunting, habitat destruction, or global warming.

My favorite of this list is the Tasmanian tiger, or Thylacine. You can see a taxidermied Thylacine at the Natural History Museum in London, but it definitely lacks the sort of charisma I imagine they had.

Isnt he a cutie?

Isn't he a cutie?