3 months on...

I've been writing this blog for about three months now, and looked at a few different aspects of the biodiversity/extinction crisis. So I think it would be good to sum up my thoughts so far, and maybe look back at the first post and see if I’m able to answer the questions I asked all that time ago in October.

• How likely is it that we can slow down the rate of biodiversity loss and extinction?
• What exactly will the consequences be if we don’t?

And whilst I feel like I've learnt a lot from the research I've been doing, I don’t think I’ve found any concrete answers to the issues I was looking at (oops). In fact, my main conclusion is that the whole issue of biodiversity loss is a lot more complicated than I had thought, but that seems to be a running theme in most of my studies. It is precisely this reason that I remain sceptical of our ability to meet the CBD’s Aichi biodiversity targets and similar measures, as the solutions, like the problem, are extremely complex.

What has become clear to me about biodiversity loss is that there’s still so much that we don’t know about the biotic response to climate change. As I discussed when looking into paleoenvironmental studies, past extinction records show us that the survival of species is hard to predict, as is the response of ecosystems to climate change. Whilst we can look to the past to inform us on potential responses, we will always be somewhat in the dark due to the unprecedented nature of the speed of anthropogenic climate change. Like with coral reefs, we don't necessarily know if ecosystems will collapse or if they will change into a different structure, how much damage they can withstand, or even if technology will advance to be able to protect them in ways that we haven't even thought of. 

In terms of society slowing down (or even stopping) the rate of biodiversity loss, there seems to be two sides to what I’ve read. On the one hand, there is much research on the loss that we will experience, with the Living Planet Report predicting massive losses in the not-too-distant future. And as I recently wrote about, climate change is already causing localised extinctions in many parts of the world. On the other hand, there is a lot of positive work being done on stemming losses and improving the prospects for biodiversity, like the reintroduction of beavers to Scotland, and the recognition of the importance of creating connected protected areas to boost wildlife. Whilst the media portrays the prospects for wildlife as constantly dire, and this is often right, there are themes of resilience and hope coming through from many species.

So I come away from this a bit more confused about what's going to happen to the world's biodiversity under climate change, perhaps rightly so - it's always hard to know exactly how the Earth system will react to changes. And even if we could comprehensively predict the biotic response to climate change, it is crucial that we do not ignore the numerous other threats to species around the world.

At the same time, I'm inspired by the progress that science is making in both recognising the importance of this issue (I struggle to remember much that I've read whilst putting together these posts that didn't outline biodiversity loss as one of the major threats of the current period), and working towards proactive strategies that can maintain biodiversity. I think that one of the important things to consider with what we know about the risk to biodiversity is that it should be a reminder that climate change will not only impact our species, but will affect all ecosystems which in turn, will affect us. 

The climate change scapegoat…getting lost in the big picture?

I started off this blog with the (I guess mostly internal) assumption of climate change being the biggest risk to biodiversity loss in the long term - the thing that would tip us over the edge into the 6th mass extinction. And I think this is something that instinctively a lot of people would agree with. It's easier to pin the great losses predicted on some large, intangible process rather than face up to the smaller more actionable causes, and climate change has been frequently stated as the biggest threat to the planet (see countless articles along the lines of “22 times the Obama administration declared climate change a bigger threat than terrorism”).

Perhaps this is why I started off thinking I would be investigating whether climate change was costing us our biodiversity, but found myself from week to week looking at individual species or ecosystems a lot of the time. Maybe it's because in one of my other modules I've been looking at large-scale remote sensing monitoring techniques as a conservation method, and I'm getting too caught up in the bigger picture. 

In a recent study by Moran and Kanemoto, researchers identified ‘hotspots’ of threat to biodiversity, stemming from consumption in the United States. The resulting images created show a great impact on species in North America and Eurasia, caused by the production of goods for exportation.  And this is only one of the major developed economies.

Moran and Kanemoto (2017) - Darker areas show higher threat from US consumption

A recent analysis of IUCN Red List data (which for many conservationists sets out the state of threat to different species) carried out by Maxwell et al reveals that in the present day, climate change is not yet the major threat to biodiversity that it is made out to be. In fact, their analysis showed that climate change only directly threatens 1,688  out of over 82,000 species studied, falling behind system modification, pollution, invasion and disease, urban development and lastly, agricultural activity (with livestock farming as the second most threatening individual activity, as per last week’s post). At this rate, it doesn’t look like many species will survive long enough to see the effects of climate change.

However, it is important to consider that this is based on a causation logic of 4 factors (storms and flooding, habitat modification, extreme temperatures and drought) and does not take into account the many potential indirect effects that climate change could have. There are other obvious limitations to looking at what ‘threatens’ a species – such things rarely operate in isolation and as I’ve realised in many of my blog posts biodiversity data is very complex and difficult to determine accurately.

So it’s not fair to say that climate change is not a big risk to biodiversity, but as Maxwell et al warn in their paper, it is crucial that action on climate change doesn’t overshadow action to reduce current threats to biodiversity. And it’s been further stated that whilst protecting biodiversity and work to diminish climate change are issues that affect each other, they are ultimately separate.

A comment by Caro and Mulder that I found interesting is “effective efforts to protect trees and reduce climate change may result in conserving only an empty forest”.  I was told in my A-level geography class that the word ‘holistic’ was key in all areas of geography, and indeed I think I put it in every essay I wrote. But I’m reminded again of the importance of a holistic strategy here. For effective management of biodiversity loss, climate action needs to be an involved part of conservation and conservation needs to include a consideration of climate change phenomena. If we’re tackling the big picture, we can’t forget about the individual components that need action. 

New year, new me! Why i'm going to try to make 'flexitarianism' work for me in 2017

It's that weird time of year... the few days between Christmas and the New Year when everything is a bit odd and nothing seems to operate as per usual. A great time for thinking up some new year's resolutions!

I'm met with eye-rolls when I mention 'flexitarianism' and I admit I use it with a fair amount of irony (but hey, it’s had a guardian article written about it, so it must be a thing). But essentially it’s being semi-vegetarian - I'm trying to be realistic with my ability to cut out something I'm so used to having in my diet, whilst also making sure my mum doesn't think I'm going to waste away from lack of meat (I'm sure the veggies I know have tried in vain to argue that point with concerned relatives). I tried going full vegetarian in 2016 and I failed not long after starting - I blame my poor cooking skills for several failures in the cooking vegetable curry area that have made me dread using sweet potatoes. So my aim for 2017 is to eat a higher proportion of vegetarian meals, and if possible to limit myself to 2 portions of meat and 1 portion of fish per week. After being introduced to the wonders of coconut milk chocolate mousse, I’m also motivated to try and use non-dairy alternatives where possible. In terms of the meat I am eating, my intention is to stay far away from water and energy intense beef, the food with the highest environmental impact.

My personal opinion is that including meat in our diets is not an inherently bad thing - my issue with our carnivorous diet is the excess to which society has taken it. The cruelty in the meat industry is a response to demands for enormous amounts of cheap meat, and the environmental costs associated with this are high. As with many things, I believe that small steps taken by many can make a big impact, and from developing a greater understanding of the risks posed to global biodiversity by climate change I am more convinced than ever that society has a responsibility to act on global environmental change.

The environmental argument for cutting down on the meat in our diets is present in literature. Globally, annual meat consumption increased by 23 kg per person from 1950 to 2005 (ref), rising in accordance with many of the other measures of anthropogenic change, and an increased consumption of beef has also been linked to regional and global climate change. According to the Food and Agriculture Organisation of the United Nations (FAO), livestock is responsible for a higher proportion of global greenhouse gas emissions than transport. Yet the majority of environmental activism encourages us to use the bike rather than a car but not to cut down on how much beef we eat.

In terms of freshwater use, meat consumption is known to be a significant contributor to water footprints, accounting for 41-46% of overall water consumption, compared with the 8% consumed for domestic use. Rising irrigation has been linked to increasingly frequent incidences of water scarcity which threatens to leave staggering numbers at risk in the future. With around 34% of agricultural land used to produce feed for livestock there is no doubt that meat consumption has played a large role in this.

Switching to a more plant-based diet would help to reduce these environmental impacts. Westhoek et al found that reducing meat, dairy and egg consumption by half in the European Union would lead to a reduction of 40% in our nitrogen emissions and 25-40% in our greenhouse gas emissions. Furthermore, nitrogen use efficiency of our food production would increase by up to 30%. These are not insignificant figures, and point to a large positive impact from more vegetarian diets.

But it’s not just emissions that are the issue, land degradation that reduces the available habitat for biota is in great part caused by the rearing of livestock for meat. 26% of ice-free land is used for grazing, and FAO outline the increased numbers of livestock as a key factor in deforestation. Even more shocking, they report that almost a third of terrestrial ecoregions consider livestock as a threat to biodiversity. If we want to protect more land for biodiversity and conserve species at risk, then cutting down on the amount we use for livestock is a sensible, and plausible, option.

There’s a lot of evidence stacked against meat consumption, and I’m going to try and keep this in mind every time I do my weekly shop.

Wish me luck!

Climate related extinctions - future fear or the present state?

Determining what exactly will happen under climate change scenarios, and whether what is happening currently is attributable to climate change, is extremely difficult but very interesting subject. Pounds et al in 1999 reported a loss of an endemic toad species in Costa Rica (Bufo periglenes) due to an increase in sea surface temperatures, the first species extinction attributed to climate change. Since then great losses in population abundances have been linked to the increased stress anthropogenic activity has placed on the planet.

The exact effects of climate change on species and proposed extinction rates are inherently uncertain and difficult to predict due to the many variables involved, and the attribution of losses to climate change is problematic as all correlation/causation arguments are. One of the most discussed effects of climate change is range shifts leading to declining population abundances, in which species migrate to a different latitude to maintain their environment at the right climate (Thomas et al, 2004). This recent paper from John Wiens indicates that climate-related local extinctions have indeed been happening in a number of species. Through an examination of studies focusing on range shifts as a response to warming climate, Wiens finds climate-related extinctions in 47% of the 976 species studied. Findings also showed more frequent impacts of climate on biodiversity in tropical areas.

Minimum change scenarios for climate change predict extinctions of 18% as a direct impact of climate change with maximum change scenarios leading to extinction of ~35% (Thomas et al 2004), but as discussed the expected losses in species populations are much greater than this. Whilst declines in population abundances does not equal extinctions, it obviously makes them a lot more likely.

Limited physiological tolerances to temperature is perhaps one of the most obvious factors leading to species loss, but according to this paper, very few studies suggest a direct relationship between temperature tolerance and local extinction. So whilst Wiens details a worrying account of current local extinctions, perhaps he is missing the bigger picture. Studies investigated by Cahill et al in 2012 indicate extinctions directly caused by species interactions leading to a loss of prey and disease, and extinctions directly caused by stress of abiotic factors leading to desiccation in trees and oxygen limitation in aquatic species.  As such it appears for these assessments at least to not be a straightforward correlation between temperatures and biodiversity loss as a result of climate change, more a complex chain of events triggered by the alterations in global climate. 4 studies even reported extinctions being the result of ‘natural climatic oscillations’, a phenomenon which occurs anyway without the influence of the human race, but which could also be subject to change through anthropogenic activity.

This range of extinction mechanisms causes only furthers the unpredictability of climate change induced extinctions. The complex nature of species interactions and ecosystem functions results in a wealth of different trajectories for biodiversity. Furthermore, whilst extinctions may be caused by human habitat modification, the presence of climate change as an exacerbating variable can’t be ignored. 

Biodiversity on the TV - Planet Earth II

Like 9.2 million other people over the last 6 weeks, my Sunday evenings consisted of sitting in front of the TV, watching BBC’s Planet Earth II – a look at the Earth’s wildlife, 10 years on from the original series. The series has captured public imagination in a way that very few documentaries manage to, and from regular scans through my twitter feed it’s clear that many others have found themselves becoming as invested in the fate of the species profiled as I have. 

What I found most interesting in the series was the episode on wildlife in cities which presented a startling look at how species have been affected by urban land use encroaching on natural habitats. But rather than just showing animals pushed out of their habitat, the approach of this episode was to show how wildlife had continued to persist in spite of urban development. It included monkeys benefiting from human presence through foraging in fruit markets in India, as well as human activity making life harder for wildlife, in heart-breaking scenes of baby turtles disorientated by lights coming off-shore.

Sir David Attenborough said in an inspirational moment in the closing scenes of the last episode “It is surely our responsibility to do everything in our power to create a planet that provides a home not just for us, but for all life on Earth”. Programmes like this leave us awestruck at the biodiversity of the world, but the real hope would be that they also show people the importance of conserving the species they are watching. Research has shown an increased environmental sensitivity in students watching nature documentaries, but there is doubt that this sensitivity carries on into action. (edit: the view that the importance of conservation often takes a back seat in such documentaries was recently commented on in the guardian here)
Such programmes need to inspire and encourage local environmental action, and an appreciation of the wildlife around us, since in reality, there is no Planet Earth two.

If anyone reading hasn't watched the series yet, i'd whole-heartedly recommend it
Here's a teaser of one of the most memorable moments from this series - an amazingly filmed scene between iguanas and snakes, the first time such activity has been caught on camera.

Some musings on insects...

The UCL Conservation Group’s ‘Insect Insights II’ which happened this week got me thinking about the smaller organisms we share the planet with. Whilst I’m not sure they’re any less likely to go out of the window when I come across them in my bedroom (sorry, arachnophiles, learning about their ecological roles has made me appreciate them a bit more. Conservation does seem to focus on characteristic fauna and larger organisms, quite obviously since they provide more visible action to be taken, and also are easier to track in case of loss.

But insects have an important role in global biodiversity, making up a massive proportion of global species - they account for more than 2/3 of terrestrial species. And like other terrestrial species, their decline is significant and concerning – with this study reporting losses in 71 species of more than 30% in the last decade, which would cause them to be considered as ‘threatened’ using IUCN definitions.

Bees are the posterchild of insect conservation, perhaps due to their significant contribution to ecosystem services, but their risk from climate change is very high. Changing phenology of plants and flowers associated with shifts in temperature risks causing difficulties for these crucial pollinators. Despite the speed of climate change, many species around the world have been able to shift their range in an attempt to adapt, but the humble bumblebee (Bombus) has shown an inability to respond to changing temperatures by altering its northern and southern ranges (Kerr et al 2015). Human land use is further damaging their ability to adapt, with the use of pesticides and removal of natural land contributing to species declines. The potential loss of bumblebees is worrying both in terms of their importance as pollinators in symbiotic relationships with plants, and also in terms of their role in ecosystem services that aid agriculture – a role that we take for granted, but is essential with 84% of Europe's crops having some dependence on pollinators.

Furthermore, insects are a key example of one of the caveats to measuring and monitoring biodiversity. It’s difficult to accurately say how many terrestrial mammals we are losing as we can’t be 100% sure how many there are, and with insects this is only magnified, with an estimated 10 quintillion (10,000,000,000,000,000,000) individuals present. Each year 15,000 new species are reported and due to the size of insects it’s likely there are many that we haven’t yet discovered.

We have little quantitative data for insects and so conservation is difficult, with the only practical solutions being to maintain known habitats. Perhaps it’s likely that insect biodiversity loss will be just another consequence of climate change that we underestimate.

Beavers - a biodiversity boost for Britain

credit: animalsadda.com

Beavers may be the new front line troops in the war against biodiversity loss (well, at least they may be in Scotland). 400 years after their extinction in the UK, the species has been formally recognised as nativein Scotland following a five year trial phase of reintroduction. Beavers have existed in small numbers in Scotland for a while through a mixture of legal and illegal introductions, but their official designation as native creates the opportunity for the species to grow in abundance in the UK, now being allowed to expand its range naturally – a development that has generated excitement amongst proponents of rewilding and reintroduction.

It was probably around this time last year that I first heard of the concept of rewilding and reintroduction of species. In a talk by George Monbiot echoing many of the themes in this article, I learned of the dearth of keystone species in the UK and the importance of these “ecological engineers” in creating a dynamic and diverse ecosystem, as well as their potential to conserve current species at risk. The IUCN has proposed reintroduction as a strategy for conservation since 1987 but it is with increasing knowledge of the importance of ecosystem structures that the idea is gaining traction, whereas before the decision to act on reintroduction was more political than scientific (Sarrazin & Barbault 1996). There is increasing consensus that trophic downgrading, suggested by Estes et al 2011 as the process of removing apex predators from nature, can be linked to reduced herbivore populations, influxes of disease, invasions of non-native species and the collapse of biodiversity.  Such is some of the impetus for conserving the large charismatic fauna that are at risk globally.

So this beaver news could be a positive development for biodiversity, with the Scottish Wildlife Trust (SWT) hailing it as a ‘major success story for conservation’, welcoming their constructive role in creating new wetlands that could provide habitat for many other species and coppicing woodland thereby increasing woodland diversity.

The SWT hopes that this will set a precedent for more species reintroductions. In developed countries where popular opinion is becoming increasingly geared towards the protection of nature rather than its continued exploitation, there may well be further opportunities- personally I’d love to see the lynx return to the UK. With the arguments for reintroduction set out as they are, in a time where our future conservation decisions have a lot riding on them, I think there could well be an argument for strengthening and diversifying the ecosystems we can to potentially mitigate loss through future climate change. The addition of keystone species also creates an incentive for creating protected areas, creating both economic benefits in the form of tourism and environmental benefits through the safeguarding of land from urban encroachment.

Despite this potential, research and action on rewilding and reintroduction seems to focus almost completely on the developed regions of the world such as Europe and North America, with little incentive or possibility for the expansion of species reintroduction into habitats in developing countries. Potentially the cost of such action would be too high to justify, especially where apex predators already frequently clash with the interests of agriculture and urban development. But as an action to improve the biodiversity of the United Kingdom at least, the option is there.