A reflection

I’m afraid to say that this post marks the end of my blogging adventure. When I look back at my first post, I realised that when I started I had visions of adhering to some sort of structure, and I had laid out in my head the order that my blog would follow. However, as I have discovered since then, that’s not really what this has been about. Instead, this blog has given me the opportunity to explore issues relating to biodiversity change. I don’t think I can say I’ve ever truly been granted this opportunity through work before, there have been no constraints and I have really free to explore a topic that I am familiar with but in a way that I was totally new and refreshing!

I have explored biodiversity changes in the context of global environmental change, writing about topics such as transformation of the biosphere, and have discovered a whole new biome I never knew existed in glaciers and ice sheets! I have shared with you my passion for hedgerows which was a particular highlight of mine.

My opinion on issues of biodiversity certainly has changed, as I have become more engaged on a personal level. The anthropogenic threats that we have lumbered upon the other organisms that we share this planet with are serious, and I think there is a need for us all to engage. I really do believe that a lack of engagement and a sense of 'this does not affect me' is what is preventing collective and powerful action. This blog has shunned me of my 'textbook' attitude that I had been guilty of viewing real-life issues with, I have been forced to engage and I am very grateful!

Like never before, it's in our hands

The ecological role of large carnivores

Following on from my last post in which I explored the status of lions in West Africa, I thought it would be useful to discuss more generally the status of large carnivores. To do this I’ll refer to a paper that was recently published in Science magazine, that reports the current understanding of the ecological roles large-carnivore species play in ecosystems, and explores the implications of their decline across the world.

The science bit

The order ‘Carnivora’ consists of 245 terrestrial species, that can be found in most of the earth’s major habitats. Carnivores are naturally rare because of their position at the top of the food web however, this paper reports that during the previous two centuries, many carnivores have experienced substantial population declines, geographical range contracts and serious habitat fragmentation. In fact, 61% of large carnivores are listed by the International Union for the Conservation of Nature (IUCN) are threatened – with 77% classified as undergoing continuing population declines.

The ecological role of large carnivores

There is plenty of evidence to show that large carnivores, such as lions as leopards, have substantial effects on the structure and function of some of the world’s most diverse ecosystems. Because these animals are at the top of the food chain, any changes to their populations will affect all other animals in the ecosystem, in a process of trophic cascade. This makes the conservation of these animals even more crucial because if they disappear then there could be severe consequences, spanning entire ecosystems!

This man talks about the importance of large animals - basically the same as I've been saying here, but just on a whole new level of enthusiasm. Watch and you'll see what I mean! Note the hands (difficult to ignore)

The paper states that our tolerance to these large carnivores needs to be increased if their populations are to be maintained. Human society needs to learn to coexist with these animals, but this will be a huge societal challenge. I wonder whether humans are guilty of competition? We too occupy a position at the top of the food chain and perhaps it is in our instinct to defend ourselves against these large carnivores or competitors. Irrespective we need to take responsibility for large carnivore populations to ensue that potentially devastating effects are not felt across whole ecosystems. We need to come up with creative solutions to maintain viable populations whilst also managing the need for increasing stock production to feed our increasing population. Perhaps allocation of protected areas (PAs) is the answer however in my opinion this doesn't seem very sustainable - after all, we can't do this forever and surely there are moral and ethical implications involved with confining these creatures in captivity? Humans need to learn to live alongside, or coexist with large carnivores, but first we need to deal with our fear!

Lions 'facing extinction'

If you haven’t yet watched the video I posted in my last post, then click here! We see lion-hearted Kevin Richardson, a zoologist and animal behaviouralist from Johannesburg, cuddling lions. The man, known as the ‘lion whisperer’, has been working in a South African game park for 16 years and has been accepted into several lion prides.  His secret? He maintains that all that is required to develop such personal bonds is three simple ingredients: love, trust and understanding – it sounds to me like this man could apply himself quite successfully to marriage counselling!

Kevin’s unique relationship with lions has captivated the imagination of many people and he has produced several documentaries that detail the struggle lions face both in captivity and in the wild. It’s this I want to explore a bit more today because after watching that video I came across a news article published on the BBC website that was also about lions but this had a more serious tone.

Through his unique relationship with lions, Kevin is able to increase people's awareness of the threats that they face. Source: The Lion Whisperer

I’m going to review this news article today and then I also want to talk a bit about a paper I have read which talks more generally about the status of some of the world’s largest carnivores, lions included.

The article begins by introducing a recently published study conducted by Phillipp Henschel and colleagues at Panthera, a non-profit organisation that directs and implements conservation strategies for the world’s largest and most endangered cats. The study synthesises expert opinion and field data to investigate the current distribution, status, and potential management deficiencies of specially designated ‘protected areas’ for lions to live in. The study suggests that there has been a ‘catastrophic collapse’ in the number of lions in West Africa, reporting that there may only be around 400 left in the region. This number is shocking. I would never have imagined it to be so low! It really is devastating and something HAS to be done – surely?

Large-scale plantations for cotton and food-crops have contributed significantly to the decline of lions in the last decade. 

The article continues, outlining concerns that the entire population of West African lions could disappear. For me, seeing a face to the threat of extinction is so upsetting. The lion is such an iconic species, one that everyone grows up with and everyone has visions of an open-African savanna, teaming with prides of lions. Clearly this is quite naïve, and unfortunately may be something of the past.

Further to this, the genetic sequence of the lions is unique to lions of this region, and so if they are lost then a unique locally adapted population will become extinct.

West African lions are genetically different from other lions. Source: The Guardian

The report estimates that the lion range is now 49,000km² roam, just 1.1% of their historic range. What has happened to the rest of their range? One word: agriculture. The collapse of lion range in West Africa is reported to be linked to large-scale habitat loss outside of PAs through conversion to agriculture (Bauer & Nowell, 2004). The organisation is calling for the lion to be listed as critically endangered in West Africa. Phillip Henschel says that the conservation of lions in West Africa has been largely neglected in comparison to lions in eastern and southern Africa, where millions of dollars a year are spent.

The report gives two reasons for the increased vulnerability of West African lions:

1. A lack of funding for conservation
2. Increasing human population and impoverished economies 

The International Union for Conservation of Nature (IUCN) urges for international help and Panthera’s President, Luke Hunter says ‘To save the lion will require a massive commitment of resources from the international community’.

In my opinion everyone is responsible for saving the West African lions and certainly it's not something that should be left to national governments. Threats as huge as this one have global consequences and morally we can't just sit back and watch these animals disappear. I have found this discussion particularly hard-hitting. What has shocked me most is the fact that I was previously unaware of the status of these amazing creatures. When it comes to this we all need to be global-citizens and become more aware of issues that are not necessarily on our doorstep - I know I'm certainly guilty of this. 

Habitat loss, habitat, habitat.

Today the African lion occupies only 17% of its historical range and is listed as vulnerable by the IUCN (Ripple et al., 2014). Its abundance has declined dramatically in recent decades because of habitat loss and indiscriminate killing in defence of humans livestock (Ray et al., 2005).

Enjoy this video before things get serious in my next post!

Anthropogenic Transformation of the Terrestrial Biosphere: A Conclusion

Over my last two posts I have investigated the topic of anthropogenic transformation of the terrestrial biosphere. With so much information at hand I want to make sure that I wrap up this topic neatly and so this post will serve hopefully as a summary.

We have seen how humans alter ecosystems both by introducing novel processes (e.g. use of synthetic nitrogen fertilisers to increase productivity) and by altering pre-existing ones (e.g. genetically modifying crops to become resistant to herbicides and pesticides).

However, not all anthromes and biomes are affected equally by humans, as Ellis (2011) explores. It is reported that densely settled anthromes, such as towns and cities and cropland anthromes, incorporate the widest variety of novel ecosystem forms and processes and so are the most intensively transformed (Ellis, 2011). In these places pre-existing ecological patterns and processes have been shifted outside their natural range. Seminatural anthromes (such as hedgerows!) are transformed at lower levels of intensity. As you may have noticed from my previous posts, I have a great interest in seminatural anthromes. I think in this context their ecological importance is made really clear, and their role as refuges for non-agricultural species in increasingly transformed cropland anthromes is brought to light.

So the big question: Have human systems irreversibly transformed the terrestrial biosphere?

Well, if we take the most conservative view, then nearly one-third of the terrestrial biosphere has been transformed into anthromes in which pre-exisiting ecosystem forms and processes have been shifted beyond their natural range and so may now be considered to be novel (Ellis, 2011). 

Ellis (2011) concludes that the terrestrial biosphere is now predominantly anthropogenic. It is believed that it has been this way since the latter half of the twentieth century, when the transition from a terrestrial biosphere controlled by natural and biophysical processes to one that is controlled by human systems, was made. The sad news is (and I find this quite remarkable) if human populations were to disappear now, the global geological record of anthropogenic transformation of the terrestrial biosphere would persist – in other words: the changes are irreversible.

I really do find this exceptional and maybe that's why I have spent so much time on this topic. To consider the human system as something so powerful that is has strained the geological record is quite extraordinary. The news at the moment is dominated by stories of the flood risk that faces large parts of the UK, and the freezing ‘Arctic’ temperatures that North America is currently experiencing. These are reminders of the huge hold nature still has over us, and so as our ability to engineer the ecosystems increases exponentially, I think it’s important that we don’t forget the power of nature.

Is it really possible that human systems have greater control over ecosystem forms and processes than natural and biophysical processes? Source: The Telegraph

Anthropogenic Transformation of the Terrestrial Biosphere: A Novel Force?

Welcome back!

As promised, in today’s post I will be reviewing the idea that human systems represent a novel force of biospheric change, in other words one that is not duplicated in nature and one that is entirely unique.

In the Ellis paper, human development is organised into three major stages. I introduced these briefly in the last post but to refresh your memory here’s a quick run-through of what we’ve been getting up to over the past 2.5 million years…

Way, way back (around 2.5 million years ago in fact) we were organised into tribes. Stone tools were up-and-coming and fire was all range. We used these new gadgets to improve our hunting and gathering livelihoods. Our population stood at about several million and by 0.1 to 0.15 million years ago we had spread across most of the terrestrial biosphere.

Our palaeolithic ancestors began to use tools in hunting. Source: BBC

This all sounds harmless enough to me, however Koch & Barnosky (2006) suggest that the use of tools and fire to clear vegetation may be responsible (or at least in part responsible) for megafauna decline. Already we’re getting quite serious, and there’s not a fossil fuel in sight!

What we are really interested here is whether or not Palaeolithic human systems transformed ecosystems in ways that were entirely novel. Yes we used fire and yes there were megafaunal extinctions, however, Bowman (2009) says that these are both common effects of climate variation and so these processes were not unprecedented at the time. No evidence of novel transformation in the Palaeolithic era, but let’s move on to something more sophisticated!

Around 0.01Ma, we (Neolithic humans) learned to domesticate plants and animals for food. We were getting really handy with evermore powerful tools (in fact I believe the first B&Q was opened around 0.02Ma) and our ability to engineer the ecosystems was on the increase! Scientists believe that at this point our populations covered the vast majority of the terrestrial biosphere and by 1800 numbers had reached 900 million! (Ellis, 2011).

New research has found that Neolithic farmers used manure as a fertiliser on crops. Source: BBC

Any signs of any novel transformations by the Neolithic human system? Well, in contrast to what Koch & Barnosky(2006) said, Smith (2007) argues that the clearing of native vegetation and herbivores and their replacement by engineered ecosystems populated with domesticated plants and animals, does in fact represent an entirely novel biological process. I suppose when you think about it the evolution of many agricultural species is no longer a natural process, it is something that has come to be entirely controlled by humans.

And finally we progress to the industrial human system where we begin to burn fossil fuels for energy,  and we develop technologies for enhancing human survival rates, such as antibiotics and synthetic nitrogen fertilisers. Ellis(2011) identifies three novel biospheric processes that were introduced by the industrial human system:

1. The use of fossil fuel energy to replace biomass fuel and human and animal labour
2. The industrial synthesis of nitrogen fertilisers to increase productivity
3. The genetic engineering of species to increase productivity and yields

Genetically modified crops account for almost a quarter of all crops grown in the USA. Source: UNEP/GRID-Arendal

All of these novel processes serve to revolutionise our capacity to engineer the ecosystem and transform it.

From this three-stage model, it seems that human transformation of the terrestrial biosphere is consistent with the development of agriculture, which we first see during Neolithic times. Various technological advancements of the industrial era, for example the development of nitrogen fertilisers, certainly act to drive and intensify land-use changes.

However, it would be wrong of me to offer you this model without giving some kind of critique. Of course, anything that tries to explain such a complex process of events over a concise number of stages always runs the risk of oversimplification and I think that this may be the case here. However what it does do is it enables us to make a rough assessment of human systems as a force for transforming the terrestrial biosphere, and this is what I hope I’ve done here!

I think one further post is needed to neatly wrap up this topic so stay posted for my summary of anthropogenic transformation of the terrestrial biosphere.

P.s. I really recommend the Smith paper I mentioned above. It gives a really interesting insight into how early humans first gained the ability to transform the ecosystems and it talks in greater deal about processes of ecosystem engineering.