Blog Extinction: a New and Tragic Phenomena

From animals.nationalgeographic.com

So this is my last post for a while, at least while I get through the last half of third year! Thanks to those of you have been reading along. But I wanted to end on a concluding point. While rewilding is an enticing idea the extinct megafauna are for now, gone. So can they help us save the wildness, particularly the megafauna, we have left?

The assessment of species vulnerability needs to be stepped up (Pearson et al., 2014), particularly in the face of climate change combined with increasing human populations and material wealth in the regions currently preserving much of the world's wildlife. These new &/ or increasing  (depending on how you see it) threats means that the IUCN Red List may need reviewing (Pearson et al., 2014). Looking at the megafauna we've lost, can future extinction be better predicted (and therefore mitigated)? The Ice Age megafauna were subject to increasing human populations and a shifting climate, with relative contributions of these factors in different regions (Stuart, 2014), much the same as today. Pearson et al. (2014) analysed the attributes that cause species to be at high risk of extinction specifically due to climate change. They found that occupied area and population size, actually already used in conservation assessments, were particularly important for predicting extinction risk. Other variables considered in this review included generation length, landscape connectivity and niche breadth (i.e., what ranges of temperatures and precipitation did their habitats include).

From Pearson et al. (2014). Variables were estimated for the year 2000. Y axes are scaled so that 0.0 is the mean value of the response

So essentially, it's pretty complicated even with modern species! And interactions between these variables can throw the whole thing off. For example, although extinction risk under climate change is highest when occupied area is small, the risk is lower when the species has a long generation time (i.e., a longer period between new generations) (Pearson et al., 2014). The papers that consider differential megafaunal extinction risk factors seem to do so as a side note, or as the last line of an otherwise largely incomprehensible (at least to me) sea of mathematical models (for example see Zuo et al., 2013). So this seems to be an area that warrants more research. Indeed, so is the topic of megafauna extinctions itself. A recent review of the current understanding of the extinctions concluded that assertions that we have resolved the debate are definitely premature (Stuart, 2014).

In the meantime, there are areas which have been sorely neglected in terms of data collection. For example Southern Asia, which has been studied much less than North America, Europe and Australia. However, Southern Asia contains an astonishing quantity and diversity of surviving megafauna, most of which is threatened to varying degrees.

The megafauna found here includes the Javan and Sumatran rhinos, Asian elephant, Malayan tapir, Indian water buffalo, banteng, gaur, Bornean orangutan, Sumatran orangutan, leopard, tiger, Asiatic lion, giant panda, sloth bear, saltwater crocodile and reticulated python. Both rhino species and the Sumatran orangutan are 'critically endangered' on the IUCN Red List. The Asian elephant, Indian water buffalo, banteng, Malayan tapir, Bornean orangutan, tiger and giant panda are 'endangered' (Stuart, 2014). That's the worst and second worst ratings. The Asiatic lion has been the focus of the Zoological Society of London's campaign Lions400 which is attempting to raise awareness of this little known species before the last 400 individuals disappear from the wild. A similar story can be told about the African continent, famous for it's megafauna.

In the face of so many megafaunal species predicted as likely to become extinct, it may be useful to look at the species that did not make it at the end of the Ice Age, and what set these survivors apart, if anything.

Overall, there is a need to focus on collecting reliable radiocarbon dates on megafaunal remains,
and lots of them (Stuart, 2014). In the case of Australia, the extinctions occurred beyond radiocarbon dating range. New dating methods will undoubtedly help to clear up uncertainties surrounding the mechanisms behind the megafauna extinctions here (Stuart, 2014).

Lutz like one Heck of a mistake

An interesting bit of news caught my eye today. The article itself can be found here. It relates nicely to my Conservation Cow post yesterday.

The Heck cattle have been adopted by European conservationists as a stand-in for the lost auroch megafauna. Heck cattle have a complicated history. However, this history seems to have been overly stressed compared to the disregard for life that the man in this interview has shown (in my humble opinion).

That fact that Lutz Heck, (a member of the Nazi elite, thoroughly bad person and a terrible scientist at that) created the Heck cattle breed should be in my opinion disregarded. They exist, and despite his blundering method and less than pure motives Heck created a hardy and less docile breed of cattle, one that stands a chance of standing in for the lost aurochsen and contributing to restoring European ecosystems. So when you see something like this, off the back of the high spirits I had raised yesterday for the Conservation Cow, it’s a bit disheartening.

The farmer has bought around 30 Heck cattle, to add to his collection of rare cattle breeds. ‘Collection’ right away has me on edge. Animals, especially fierce ones like the Heck cattle, should not be collected. The only one who stands to benefit there is him if he makes a tidy profit on what I think of as the current ‘indie food’ market. If you haven’t noticed already, you will probably see some purple carrots or lumpy potatoes soon. Lidl has even brought out kangaroo steaks. It smacks of the Victorian zoophagy obsession. The rarer it was, the better. Costly signalling anyone? 

The reason Heck cattle have a chance of being a conservation cow for is that they may have some of the wits that the aurochsen possessed. Cows were not always the blundering, slightly dim animals we see today. We made them that way in our selection for meek, placid animals that gave us no trouble (Levy, 2011). So was purchasing a breed of cattle designed to not be kept domestically, to live on a farm, really a great idea? No. It wasn't. Predictably, the animals paid the price and the man profited. He killed 20 of the most aggressive bulls because they would happy have “wiped [him] from the face of this earth”. The 6 that remain are the ones that gave him least trouble. The 20 dead have been turned into burgers. Yet still the main focus seems to be on the word ‘Nazi’.

The video also features a man giving his professional opinion of the Nazi party’s use for the Heck Cattle. While I agree with what he says, I feel he has left out a large part of their story. 

Lutz Heck was obsessed with lost beasts and believed they could be brought back to life. He assumed that the biological legacy of aurochs lived on, divided up among domestic breeds. He thought that by crossing various breeds of domestic cattle, he could recreate the aurochsen (see, I told you about the bad science). Obviously, he was completely wrong. He created a new breed of domestic cattle. aurochsen were giants compared to Heck cattle, standing 6.5 feet at the shoulder (Levy, 2011). They were smarter, faster, more graceful and fearless than domestic cattle. A few years of breeding by Heck couldn't undo thousands of years of selection for docile, meat-heavy cows (Levy, 2011).

For Nazi officials, the goal of purging people they deemed inferior from society went hand in hand with resurrecting Europe’s megafauna. They wanted an imagined ‘pristine’ state of nature (Levy, 2011). In fact, this is an issue for modern conservationists. This ideology is a myth, there is no one ideal state, and in any case, humans have been altering our world for thousands of years before we came to decide what was pristine and what was not.

Phew, thank goodness for science blogs, or it would have taken me weeks to find someone who would listen to that rant! 

The Conservation Cow

From carbonsoultionsglobal,com

Cows get a lot of bad press. Many people have heard that cows produce greenhouse gasses, including methane. According to a report in 2006 by the United Nations Food and Argiculture Organisation (FAO) our diets, and the meat in them release more carbon into the atmosphere than transportation or industry (Scientific American: The Greenhouse Hamburger, 2009). Methane is responsible for 20% of the warming created by long-lived green house gasses since pre-industrial times (Kirschke et al., 2013).

From autonomousmind.wordpress

Garnett (2009), and many other scientists, seem to agree that domestic livestock are a problem for both atmospheric carbon and valued ecosystems such as rainforest, which is cleared to make way for cattle ranches. In fact the post on Conservation by George Monbiot that I discussed in my last post, he mentions that domestic livestock are a major cause of global warming. He also points out that, in human-impacted systems, wild herbivores can be as well.

In part, I disagree with this view. I think that a change in how we use our livestock could turn them from an ecological nightmare to a key part of healthy ecosystem. A carbon source to a carbon sink. This has been suggested before, often in terms of altering their diets (For example, see Aquerre et al., 2011). But I think it needs to go further than that.

Wild herbivores can turn an ecosystem from a sink to a source of carbon in the presence of human interference. An example of this can be seen in the Serengeti. Pre-1960's, wildebeest numbers there fell from 1.2 million to 300,000 (Monbiot, 2014). The result echoed the hypothesised mechanism behind the loss of Australia's rainforest, which covered much of the country in Pleistocene times (Levy, 2011) (Monbiot, 2014). In the Serengeti, the decline in wildebeest caused dry vegetation to accumulate. This abundance of fuels resulted in wildfires, which burned around 80% of the Serengeti every year. Wildebeest numbers have since increased with conservation efforts, and now more vegetation is eaten, and their dung in incorporated into the soil. This represents a transformation of the Serengeti from a source of carbon to a sink. This shift is equivalent to the entire (current) emissions of carbon dioxide from burning of fossil fuels in the whole of east Africa (Monbiot, 2014).

In the US, cattle ranches occupy huge areas of arid land. They trample and munch up the strips of vegetation, collapse stream banks and drive out native animal populations. The deterioration of these habitats fueled a campaign to remove cattle from federal rangelands (Levy, 2011). Naturally the ranchers were unhappy. But was this the right thing to do?

This land has supported large herds of herbivores since long before the end of the Ice Age (Levy, 2011). These included native horse, camel and bison. The horse and camel went extinct in the end-Pleistocene, but the bison survived up until only a century before the conflict over the rangeland domestic cattle began (Levy, 2011). The bison numbered in the tens of millions. From 1830 to 1880, a deliberate effort to slaughter them reduced their numbers to only a few thousand (Knapp et al., 1999). At the same time, much of their habitat was ploughed up by farmers.

More recently, conservationists working on native prairie land began to experiment with introducing bison back into the mix. The study by Knapp et al. (1999) on bison ecology highlights the way the bison shape the landscape. Their faeces rich in nitrogen increases plant growth while their differential grazing (cattle are picky eaters) creates a diverse plant community (containing more species) in different stages of growth depending on when the bison were last there (Knapp et al., 1999).

From americanprairie.org
A bison herd on american prairie

This diversity increases the habitats available to the native wildlife, particularly the prairie birds (Knapp et al., 1999). For example, the lesser prairie chicken needs tall grass to hide its nest in, but short grass for its courtship displays (Levy, 2011). So bison play an important role in a diverse prairie ecosystem (Knapp et al., 1999). But they way they do so is through behaviours that they share with the domestic cow (Levy, 2011). So then, why do environmentalists dislike the domestic cow? And why are ranchers so afraid of the bison?

Cattle graze during spring and summer. In the autumn they are fenced into paddocks and fed hay. Bison on the other hand are free to roam and aren't supplemented in the winter months (Levy, 2011). The long-term study by Knapp et al. (1999) showed that when managed in the same sustainable way, both cows and bison increase the diversity of native prairie plants. The way the cow is used by people has a greater effect on its environmental impact than any behavioural or other traits (Knapp et al., 1999).

The best ranchers in the US find ways to keep their cattle on the move. In places like the UK, it's more difficult to imagine how this would be achieved, since we have very few large open spaces. Sadly, the open spaces remaining in the US are under threat from being sold to create suburban ranchettes, with far lower potential for sustainable use (Levy, 2011).

During the Pleistocene, grazers wandered wherever the fresh grass was, allowing the soil time to absorb the nutrients and the plants to grow. Dire wolves and other predators helped by creating a landscape where herbivores kept on the move and avoided certain areas out of fear (Levy, 2011). Domestic cows need to be moved by humans, requiring more effort than other methods. But the rewards are healthier grasslands, cattle and wildlife (Levy, 2011).