At a time when much of the world is busy rewilding, some Australia’s conservationists want to kill millions of kangaroos including Red Kangaroo, the country’s largest remaining megafaunaThe largest animals that represent the top of the trophic pyramid. These are the final building blocks in ecosystem structures for maximum entropy production. Megafauna can be measured at any spatial scale. The largest animal that ever lived on Earth is the Blue Whale. In a grassland, spiders could be considered megafauna The term is generally reserved for animals larger More species, an animal that stands 2m high and can weigh 85 kg. Killing kangaroos destroys Australia’s environment. It makes no sense!
Australia likes to wage a war on wildlife. Discontent with living in a megadiversity country, we like to hunt, shoot and “manage” everything from the possums in our gardens, to Saltwater Crocodiles in the NT. Benign creatures like Koalas succumb to neglect, unless they are a hinderance to forestry or developers, at which point they become an inconvenience. We seem to be in (what we’re led to believe) is a struggle to the death with creatures that are out to destroy our lifestyle and a landscape that will kill us, if we allow ourselves to be distracted for even a moment.
Killing of animals for conservation
Killing of animals by conservationists is nothing new but I am particularly alarmed at the intention to short-circuit and manipulate megafauna populations, where there is ample evidence loss of this wildlife is behind many of the environmental problems we face today, including the decline in soil fertility, food security, habitat integrity and ultimately, climate stability.
It’s especially concerning that the conservationists extolling such rash moves as mass-culls, already know that ecosystem malfunction is to blame.
The article that drew my attention most recently, was published in the Guardian Newspaper and titled “How kangaroos could be jeopardising conservation efforts across Australia”.
Scientists interviewed by journalist Graham Readfearn were quoted as saying that historic culling and exclusion of dingoes has seen the kangaroos’ natural predator all but disappear, so that “across vast areas of the country, kangaroos have increased in number” but that “reintroducing the native canine is incompatible with farming”.
Those two statements are part of the story.
Worldwide, the collapse of predators has led to the destabilisation of food chains, with a subsequent increase in disease prevalence, pests and ultimately loss of animal biomassThe weight of living organisms. Biomass can be measured in relation to the amount of carbon, the dry weight (with all moisture removed) or living weight. In general it can be used to describe the volume of energy that is contained inside systems, as the size of animals relates to their metabolism and therefore, how much energy they contain and More, soil fertility and ecosystem integrity.
In Australia, however, dingoes were not the only predator. The forced removal of Aboriginal people from the land by Europeans removed another kangaroo hunter. Ideas like ‘apex predator’ don’t exist in nature, only in our scientific literature. EcosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More are complex interactions between people and animals alike. It’s the shape of the system that matters, not one component of it.
HOT OFF THE PRESS A study just published this month in Landscape Ecology shows the massive impact that Australia's Dingo-proof fence has had on vegetation. The fence is over 5,500km long and crosses three states. On the dingo-less side, there is signficant "suppressed vegetation growth following rainfall, due to high grazing pressure" [3].
If conservationists give up on wildlife, what hope do we have left?
It is disappointing to hear land restoration organisations resorting to the most extreme management methods, especially as they admit, these are likely to be economically unachievable (Australia can’t even meet current kangaroo cull targets on farmland). It means conservationists will end up killing kangaroos on their own patch and the results won’t be scalable–and what is the point in conservationWhy is animal conservation important? Animal conservation is important, because animals are the only mechanism to create biodiversity, which is the mechanism that creates a habitable planet for humans. Without animals, the energy from today’s plants (algae, trees, flowers etc) will eventually reach the atmosphere and ocean, much of it as carbon. The quantity of this plant-based waste is so More if it isn’t scalable?
Australia’s impending crisis is one of land integrity, including farmland and as I wrote the other day, this can’t be addressed without wildlife.
It’s the duty of conservationists to know this and to find a way to restore ecosystem processes that are landscape-scalable, as our food security and future depend on it.
Anyone familiar with my writing on this blog will also know my belief, that we have a global problem when it comes to how we value wildlife.
Animals should never be an after thought
Conservation scientists, ecologists, land managers, farmers, responsible authorities, gardeners and naturalists, all regard animals as an after-thought, like the icing on the cake. Far from it, animals are integral to ecosystem processes and without them, we have no hope of addressing climate change and food security challenges because animals are the driving mechanism behind ecosystem stability–but only if they are in correct proportions, according to their size and energy consumption. This is why we cannot exist on a planet with no animals, because plants massively destabilise ecosystems.
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Australia’s farming future will not be secure long-term, if kangaroo numbers are reduced further and this will obviously mean reintroduction of dingoes. If this is incompatible with farming now, it may not be for long, as there may be few viable farms left in a few decades (except those perhaps, that continue to plough more soil-killing chemicals into the ground). “Business as usual” isn’t protecting food security or livelihoods.
It’s the duty of conservationists to know this and to find a way to restore ecosystem processes that are landscape-scalable, as our food security and future depend on it.
Killing animals increases ecosystem risk
I also suspect, that some of the problem the conservationists face, are caused by external factors and their culls would only be contributing to this, thereby increasing their own risk. The numbers of kangaroos may not be as high as they think but if you create ideal food conditions for wildlife, in an area surrounded by agricultural desert, you’re obviously going to get an influx of animals. Isolated reserves don’t function(Of an ecosystem). A subset of ecosystem processes and structures, where the ecosystem does something that provides an ecosystem service of value to people. More, because their structure and processes are incompatible with their surroundings. QED, you need to get farmers on side to make conservation sustainable. It has to be a whole-landscape approach, or nothing at all.
How many countries in the world can boast having a megafauna species more abundant than its human population?
It’s highly likely that kangaroos are increasingly drawn to the most profitable areas of conservation and farmland, due to the constant erosion of land fertility elsewhere. Densities increase in one place and because humans think in terms of short spatial distances, we are led to thinking this is an epidemic, whereas it could equally be a sign of impending collapse caused by ecosystem instability. I wrote about this recently in terms of sharks and reductions in ocean productivityThe power of an ecosystem to process energy. The most productive ecosystems have reached a steady stable-state with maximum entropy production. That’s to say, the number of species has reached an optimum and the functions they fulfil, have translated free surplus energy into nutrients that is either stored inside plants and animals, or is entrained within the biological cycles that More.
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Then there is the question of what is a natural and self-sustaining population? What if more kangaroos would lead to lower pressure on farmland?
What is a natural population of wild animals?
We have a shocking track record of making linear assumptions about ecology e.g. assuming more animals means less grass–what we’re actually observing, in this case, is decline in a steady stable-state(of an ecosystem) where free surplus energy is minimised, where there is maximum entropy production and minimum waste. In such a system, there is expected to be relatively small fluctuations in atmospheric and other chemistry and where disruption or disturbance occurs, the resulting changes can be absorbed quickly by a succession of new plants and animals that enter to fill More ecosystem. We’re measuring a broken system, which leads to gross bias in our experiements. An ecosystem in disrepair will change chaotically, whatever we do, until we can restabilise things. Animals are the only way to do that. I’m not suggesting this will be easy but the more we remove animals, the greater the problem becomes.
Raymond Mjadwesch has attempted a pre-European settlement estimate of kangaroo numbers. While his calculations are basic, his results are is not likely to be far off the mark (as endorsed by Dr Johannes Bauer). Scientists these days use historical climate and environmental data, to modelThe process, either mathematically or in the human brain, of creating an internal version of something that we can refer to, to better understand how it functions and our place within. Scientific modelling is where we take the best knowledge we have and build a version of what will happen, if we assume certain parameters. For example, we might model More ancient megafauna populations [1] and these are just as prone to error but when you can reasonably find an order-of-magnitude (10x) difference from present day, you can conclude a massive biodiversityWhat is the definition of biodiversity? When we ask, what is the definition of biodiversity? It depends on what we want to do with it. The term is widely and commonly misused, leading to significant misinterpretation of the importance of how animals function on Earth and why they matter a great deal, to human survival. Here I will try to More loss.
The Sahara serves as an example of a wider historical neglect of deserts and the human communities who depend on them … approaches must accommodate mobility of both people and wildlife … to halt further degradation of deserts and to improve their status for both biodiversity conservation and human well-being. Only by so-doing will deserts be able to support resilient ecosystems and communities that are best able to adapt to climate change. [2]
Mjadwesch supposes there were about 220 million kangaroos in 1788, compared to about 40 million today. On a side note, isn’t that still amazing? How many countries in the world can boast having a megafauna species more abundant than its human population?
Let’s start thinking in terms of ecosystems
When I hear losses like that, I don’t think in terms of abundance, I think in terms of ecosystem processes and connectivity (biodiversity). If each kangaroo continuously connected with other components of an ecosystem: grasses, nutrientA substance that contains the raw materials for life. At a chemical level, these are contained inside compounds that are absorbed into the body and essential energy-containing molecules are extracted, so that energy can be transformed into other chemical processes that use the energy for living. More cycles, other animals and birds … every action, creating an equal and opposite reaction with the environment, then the losses are geometric–incalculably high. By thinking in terms of numbers and rarity, we ignore the biodiversity principle, that ecosystems operate on a far more complex level. This contributes to linear thinking and poor conservation judgement.
A few percent loss in a species’ abundance can translate into immeasurable losses in nutrient cycling and it’s the rate of fluxIt's not the amount of energy in a system that makes it possible for us to feed ourselves, it's the energy flux (the rate at which energy flows). For example, you can have a full water tank in your house but it's hardly any use to you, unless it's able to flow out of taps. This simple logic, proves why More of nutrientsEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More through soil by kangaroos, for example, that is the major contributor to the land. If there isn’t enough grass, there aren’t enough animals!
This mistake that conservationists make, is endemic in much ecological thinking worldwide. The protagonists of kangaroo culls are thinking about vegetation as separate from wildlife. In this case, it’s led to the ill-informed conclusion that kangaroos are broadly incompatible with conservation and stymies efforts to restore habitat at scale, where long-term stability would be entirely dependent on them. We’ve created an imaginary vendetta against the animals we most need.
Loss of megafauna will become a defining factor in our quest for human survival in years to come and here in Australia, we have a globally-significant, remaining example. That puts us in a unique position in the world but before we can make a difference, we need to make our peace with wildlife.
Spotlight
Scientists have discovered that killing dingos breaks down social structures leading to higher levels of livestock predation, putting pay to arguments that culls are a prudent way to protect livestock. Read more.
References
- Broughton, J.M. and E.M. Weitzel, Population reconstructions for humans and megafauna suggest mixed causes for North American Pleistocene extinctions. Nature Communications, 2018. 9(1): p. 5441.
- Durant, S., et al., Fiddling in biodiversity hotspots while deserts burn? Collapse of the Sahara’s megafauna. Diversity and Distributions, 2014. 20: p. n/a-n/a.
- Fisher, A.G., Mills, C.H., Lyons, M. et al. Remote sensing of trophic cascades: multi‐temporal landsat imagery reveals vegetation change driven by the removal of an apex predator. Landscape Ecol (2021). https://doi.org/10.1007/s10980-021-01206-w
