When it’s Gone: The Human Island (Chapter 8)

“Oh, and spare me your huffing about biodiversity, sustainability and my children’s children’s children.

“You see, I’ve seen the dodo…

“… looking at the goofy thing, I felt serenely confident that there was not the slightest gap left in my life by its passing, just as I have no reason at all to regret never being able to see a herd of tyrannosaurus rex in my front garden.”

“Shouldn’t we just harden up about this whole “endangered” racket?”

– Andrew Bolt, July 14th 2010, Why save an animal just begging for extinction?

Few others could better sum up the nonsensically extrinsic and apathetically self-serving attitude that I wish to address in this series better than this journalist. Such an attitude would sell out long term prosperity, for a quick dollar on the premise that both the Dodo and the T-rex were unessential for local environments. It is an openly flawed and terribly weak rhetorical argument, but is widespread and something I too often hear.

By such logic, we could condone the eradication of all known pollinators of foreign continents as we would be unlikely to be affected, at least in the short term, by their absence. As discussed in the previous chapter, pollinators are important field-hands in agriculture, however, if we were to lose them elsewhere, we may feel confident that the worst that could happen to us personally is the loss of some exotic imported fresh produce.

In chapter 3, Biological Diversity, I compared an ecosystem to the crew and workings of a submarine. In chapter 5, Nothing is Wasted, I made the point that any subtraction from an ecosystem is a trade off. It is not always a clear and easy decision to decide what species is important and which isn’t, or to what degree of abundance is required to fulfil the effort required for a certain service. Likewise, diverting resources and ecological services may have ramifications that take a long time to be noticeable or may occur many hundreds of kilometres away.

To firstly use Andrew’s example species; tyrannosaurus rex and the Dodo, we have two very different situations.

T-rex is undoubtedly one of the best known species of dinosaurs to have been alive to witness the end of the era of reptilian giants. This occurred of course, around 65 and a half million years ago. In the wake of a mass extinction event, ending the Cretaceous period, the world was a far less biologically diverse place. There was room to move, so to speak – new niches where opening and with it, new species began to emerge. With the large animals no longer around to utilise much of the available resources, new types of ecosystems were able to form; the rules of the playground had changed. To reintroduce T-rex (they were unlike to move in herds by the way), would cause a dramatic pressure to ecosystems that simply had not developed to support it. Being a top-predator, they would be very unlikely find enough meat to persist. If we were talking about an herbivorous giant of the Cretaceous, we may see it literally eat itself out of house and home. In essence, what we’re talking about here is something that we’re all too familiar with (especially in Australia) – introduced species, but on a massive scale. Clearly, foxes, rabbits and cats have been good for Australian ecology, right?

The poor Dodo, being Andrew’s main target for mudslinging, has been the endless ecological joke, which quite obviously undermines this unique species.

As with the chef of chapter 3, the absence of the Dodo didn’t really have a noticeable effect on the ecosystem of Mauritius until the mid twentieth century, when it was realised that only 13 Tambalacoque Trees (Sideroxylon grandiforum) remained; all of which were over 300 years old, although these trees seem to produce fertile fruit [13]. Temple (1997) suggested that it was essential for the fruit to pass through the dodo’s gizzard to remove the thick protective seed coat. Since Temple’s paper, there has been some debate as to whether the relationship between the Tambalacoque tree and the dodo was really significant, as there remains insufficient evidence – for instance, numerous other species on the island became extinct around the same time who may have also treated the seeds – however, such relationships are not rare (whether it’s digestive treatment or simply pulp removal or seed transfer) [3].

Less ambiguity remains in the wake of the lost Passenger pigeon, which overharvest and landscape use change successfully irradiated by 1914. Flocks of this species numbered in the many millions, meaning that their presence and ecological perturbation was immense. There is little question that these flocks were able to alter environments, both through seed dispersal and urea fertilisation [3].

It has been suggested, for instance, that both the Sand cherry (Prunus pumila) and American Beech trees (Fagus grandifolia) at least partially owe their previous distribution to the Passenger pigeon, which has been on the decline in range for both species in recent decades [3].

Understandably, the loss of the Passenger pigeon, regardless of its importance to the historical ecosystem of eastern North America, is yet another species the Andrew Bolts’ of the world would simply shrug their shoulders at. However, what if the declining or absent species was an important regional pollinator or pest controlling species on agricultural land?

Current agricultural methodology is leading to a slow decline in remnant tree abundance which in turn is likely to reduce the abundance of numerous animal species, such as birds and bats, that rely on them to move among fragmented woodland patches that remain [9].

Clearly, when species become locally extinct, so do the services that they previously provided. As these services tend to make other processes possible, or assist in recruitment of other species, ultimately the entire function of the local ecosystem is changed. Once an ecosystem is significantly degraded it will be defined by different processes and thus will no longer provide the same benefits as previously. For example, without suitable habitats for pest controlling species, such as birds, bats and certain invertebrates, pesticide is the only option. Pesticide is likely to reduce soil ecology as well, meaning that the effort of soil treatment is also included work for the farmer (raising costs, lowing quality). It’s a negative feedback process of poor agricultural practices and increasingly evidence in large scale monoculture. This is likely to be the future of agriculture where woodlands are eventually lost, due to current land management [9].

Far from being an “endangered racket”, species conservation is quite literally conserving an easier life. You don’t feed more people by creating a genetic waste land, but by stimulating life and opportunity – increasing activity. You don’t make your work easier by removing all the species able to provide effort and thus work, but by making the environment more suitable for more hands, that is to say, increasing biodiversity.

The Andrew Bolts’ of the world might feel serenely confident as they watch yet another species move down the one-way road of extinction. However I’m not confident that a biological wasteland can adequately provide the standard of living that we are currently able to enjoy.

Reference
[13] Temple, S. A. (1977) Plant-Animal Mutualism: Coevolution with Dodo Leads to Near Extinction of Plant. Science. 197(4306): 885-886.
[3] Catling, P. M. (2001) Extinction and the importance of history and dependence in conservation. Biodiversity. 2(3): 2-13
[9] Fischer, J., Zerger, A., Gibbons, P., Scott, J., and, Law, B. S. (2010) Tree decline and he future of Australia farmland biodiversity. PNAS. 107(45): 19597-19602. doi:1008476107.

This is chapter seven of the series The Human Island: A Place of Ecological Ruin. To see the previous chapter, click here. As the series grows, the complete work can be found here.

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