Northern White Rhinoceros – On the Brink of Extinction

*Guest post by Monica Choy -one of several posts selected from the graduate EES3001 Scientific Literacy course at University of Toronto-Scarborough.

Photo credit: Elodie A. Sampere, Getty Images

Suni, a 34 year old male northern white rhinoceros, died on October 17, 2014 of natural causes. His death reduced the total number of known northern white rhinos to an alarming six individuals, which has brought his species one step closer to extinction.¹

Suni was born in a zoo in the Czech Republic and was the first of his kind to be born in captivity. Unfortunately, northern rhinos are a finicky species when it comes to breeding and with increasing pressures from poaching, it became critical to provide the animals with a natural, comfortable space.

As a result in 2009, Suni and three others were transported to the Ol Pejeta Conservancy in East Africa.  It was believed this change in scenery would most accurately imitate their natural environment.² Rhino conservationists anticipated that the rhinos would then breed naturally and provide a healthy calf that would bring new hope for the waning species.

Even before these desperate attempts to keep the species going however, the history of the northern rhino has been a sad one. At the time of Suni’s birth, his species was on a very slow rebound. Northern white rhinos had been excessively poached for their horns, and their initial population of over 2,000 animals declined to a shocking 15 rhinos by the late ’80s. Conservation efforts were ramped up in the ’90s and it looked as though the animals were making a gradual comeback. Unbelievably, poachers also increased their efforts and knocked the numbers back down to below 10 individuals by the mid-2000s.³

Northern white rhinos were declared extinct in the wild by 2008.

The likelihood that Suni’s species will become extinct in our lifetime has increased significantly with his death. And although the Ol Pejeta Conservancy will continue trying until the bitter end with the use of techniques such as artificial insemination, the precarious position the northern white rhino is in, as stated in their press release, is “a sorry testament to the greed of the human race.” ¹

The extinction of such a charismatic species is a tragedy and should bring awareness to how heavily humans really affect our environments. Although the northern white rhino may be on the brink of extinction, there are still a countless number of other species out there that need our help. It is up to us to work together in order to keep other species as far from the fate of the northern rhino as possible.

More information

¹Ol Pejeta Conservancy press release  - http://www.olpejetaconservancy.org/about/news/breaking-news-ol-pejeta-conservancy-loses-one-its-northern-white-rhinos

²Northern white rhino conservation project - http://www.olpejetaconservancy.org/sites/default/files/NWR_FAQ_FINAL.pdf

³WWF profile of the northern white rhinoceros - http://wwf.panda.org/what_we_do/endangered_species/rhinoceros/african_rhinos/white_rhinoceros/

Waste not, want not? How human food waste changes ecosystems

Daniel Oro, Meritxell Genovart, Giacomo Tavecchia, Mike S. Fowler and Alejandro Martínez-Abraín. 2013. Ecological and evolutionary implications of food subsidies from humans. Ecology Letters. Volume 16, Issue 12, pp 1501–1514. DOI: 10.1111/ele.12187

Humans have always been connected to their environment, directly and indirectly. Ecologists in particular, and people in general, have been thinking about the causes and consequences of these connections for hundreds of years. One form of interaction results when human food resources become available to other animals – for example, through waste dumps, crop waste, fishery by-catches, bird feeders, or road kill. Starting with middens and waste piles in early human settlements, our food waste has always passed t

Garbage dump in India.

o other species. And while rarely considered compared to human impacts like habitat destruction and climate change, a new review by Daniel Oro and colleagues argues that these subsidies have shaped ecosystems around the globe.

Human food waste (aka subsidies) may come from a variety of human activities, with the three most prominent being crop residuals (remnants of harvest remaining on fields), waste dumps, and fishery discards (by-catch thrown overboard). Each of these forms of subsidy occurs globally and large numbers of species rely partially or completely on them for food. For example, dumps are global in distribution, and contain enough edible waste to attract 20-30% of all mammal and bird in a region (particularly omnivorous and carnivorous species). Crop residues usually attract herbivorous or granivorous species (particularly birds), while fisheries’ waste alter marine ecosystems. Eight percent of all catch (~7 million tonnes!) is simply released back into the ocean, and this supplements species across the food web, including half of all seabirds.

Food waste from human activities may not seem so terrible – after all, they are predictably available, easy to access, fast to forage, and can lead to increased condition and fertility among species that take advantage of them. For example, seabirds foraging among fishing boats for by-catch take advantage of the predictability of boat (and food) appearances and as a result have decreased foraging time and areas, higher individual fitness and reproductive success, and ultimately increased population growth. But the authors suggest that these benefits must be considered in a more complicated web of interactions. After all, human food subsidies tend to be much more predictable than natural sources of food and quickly have large effects spanning from individuals, communities, ecosystems, and evolutionary pressures.

Individuals often, though not always, experience positive effects from subsidies – increased biomass, fertility, and survival, accompanied by changes in dispersal and ranges. If food waste draws in high densities of individuals, it may be associated with greater disease occurrence, or draw in predators attracted to easy pickings. Populations also often respond positively to food subsidies, and become larger and more stable as food waste availability increases. But this boon for one species can cascade through the food web, and have large negative effects in communities and ecosystems. For example, yellow-legged gulls are found around dumps and fishing trawlers, taking advantage of the quantities of food available there, and as a result have increased greatly in population. The downside is that in turn these larger populations increase predation pressure on other vulnerable seabird species. Seabirds in particular can create complicated interactions between human food waste and far-flung ecosystems, connecting as they do both terrestrial and marine systems, moving nutrients, pollution, and calories between systems and through trophic levels.

Snow goose exclosure in northern Canada.
Only the small green rectangle has avoided goose grazing.

A famous example of the unexpected consequences of waste subsidies is the snow goose (Chen chen caerulescens). Snow geese have moved from feeding predominantly on marsh plants to landing en masse in farmers’ fields to feed on grain residues. This new and widespread source of food lead to a population boom, and the high numbers of geese stripped away the vegetation in the arctic habitats where they summer and breed. Agriculture food subsidies in southern habitats were felt far away in the arctic, as migratory snow geese tied these systems and food webs together. Though snow geese are unlikely to lose their new source of food, other animals may face plummeting populations or extinctions if food sources disappear. Until the 1970s, in Yellowstone, grizzly bears fed nearly exclusively at a local dump that then closed: the result was both increased mortality and rapid increases in foraging distances and behaviours.

Finally, and of most concern, food waste subsidies can alter the selective pressures a population faces. Species that become reliant on dumps or fields for food may experience changes in selective pressures, leading to selection for traits necessary to exploit these subsidies, and a loss of genotypic/phenotypic variation from the population. Changes in selective pressure change with the situation, of course. In the case of Yellowstone, the dump closure and loss of food source seemed to have large effects on traits important for sexual attractiveness in males, suggesting potential effects on reproductive success. In the best known (and my favourite) example of the selective effect of human food waste, dogs eventually were domesticated from wolf ancestors. Of course dumps can also relax selective pressures, if they allow individuals in poor condition (juveniles, the elderly) to successfully feed and reproduce.

Though food waste subsidies are clearly important and can have wide ranging effects, it is worth noting that the effect and importance of food subsidies is context-dependent. Studies seem to indicate that effects are greatest when food is low naturally or habitat quality is poor; in high quality systems, food waste may only be used by juveniles or individuals in poor condition. Unfortunately, as humans degrade natural habitats, subsidies are only likely to increase in importance as a food source for species. The extent and effects of human food waste are yet another legacy of the global alterations the human species has made. Unfortunately, like so many of the changes we have made, the issues are complex and transcend political and regional boundaries. Practices in one system or nation are tied to effects in another nation, and this complexity can make it difficult to monitor and measure the effects of subsidies as thoroughly as is necessary. This review from Oro et al. certainly makes a case for why our garbage needs to receive more attention.

One example of the ecosystem wide effects of subsidies: here, fisheries inputs.

Predator-human conflict: the emergence of a primordial fear?

There is something terrifying and at the same time captivating about the idea of a large, wild, mysterious predator. The very idea that a large predator is near by makes us feel vulnerable. Every year, news stories about wild animal attacks appear in numerous publications and on many television shows. Human death at the fangs or claws of a wild beast is at the heart of many legendary stories and probably sown into the fabric of our being by millennia of ever present risk from large predators. This characteristic of our human experience, I think, dictates our response to animal attacks. Stories of animal attacks are usually concluded with statements about having or attempting to track down and destroy the guilty animal.

Such is the case for three recent animal attacks in Canada. In late October, 2009 in Nova Scotia, a raising 19-year old folk singer was killed by a couple of coyotes while hiking. It is difficult to find meaning in such a horrendous death, but the narrative, told by reporters, was essentially to rest assured that one of the coyotes had been killed and the other was being tracked and would be destroyed. There were two cougar attacks in early January, 2010 in British Columbia, that basically ended with the same reassurance. In the first, a boy was attacked and his pet golden retriever courageously saved his life. A police officer arrived a shot the cougar which was mauling the dog -an obviously legitimate response, and the news story again reassures us that the animal was destroyed. And don't worry the hero dog survived. In the second cougar attack, another boy was attacked, and this time his mother saved his life. But again the story narrative ended by reassuring us that the guilty cougar, and another cat for good measure, were destroyed the next day.

After reading these stories, I asked myself two things. Why is our response to destroy predators that attack? And why do we need to be reassured that this has happened? In defence of the predators, they are just doing what their instincts tell them to do, and most often their only mistake is that they selected their prey poorly. But the reality is that there are only 2-4 cougar attacks per year and only 18 fatalities over the past 100 years. Why do we fear such a low probability event? In contrast, automobile accidents are the leading cause of death in children under 12 in North America. Thousands of people die, and millions injured in car accidents every year in North America. Recently, in Toronto, were I live, 10 pedestrians were killed in 10 days, yet my heart doesn't race when I cross a street. If our fears and responses to human injury and death reflected the actual major risks, we would invoke restrictive rules regarding automobile use.

We believe that we can live with nature in our backyard. But when that close contact results in an animal attack, human fear seems to dictate an irrational response. Do we really expect predators to obey our rules? Can we punish them enough to effectively tame them? We cannot, and I hope that our approaches to dealing with human-animal conflict can better deal with animal attacks, in a way that does not subjugate large predators to whims of our fears.