Hunting - A Bear Necessity?

A nasty note on which to start the new year, but the US Fish and Wildlife Service (FWS) has announced that their intend to remove protection from Yellowstone's grizzly bear population in the coming year. As someone who has had a grizzly bear themed calender for the last two years, my immediate reaction to this is one of shock and disgust. For a moment, however I will attempt to step back from my bear loving self and take a look at the reasons behind this decision.

Adorable animal which should clearly not be hunted; Source.

For the past 40 years, the bears of Yellowstone have been protected by hunting and have enjoyed population increases and range expansion under this protection from the Endangered Species Act (ESA). This protection was not undue, the grizzly population suffered huge losses from excessive hunting during the 1900s which earned them a place on the IUCN red list. The recovery of their population, however, has put pressure of the US FWS to revoke their special status, from state officials. The proposed new system would involve handing over the management of bear population to state level, after the delisting would remove federal protection. The agreement places no limit on the hunting of bears outside of the central Yellowstone management area, and within that splits the bears between the three states which share the region - Wyoming, Montana and Idaho. There are some loose pledges to maintain the bear population in the management area above 600, but nothing concrete except an apparent need to shoot at things.

Arguably, the new laws would promote, rather than limit the killing of bears. There are underlying societal and economic reasons why there is such animosity towards bears, and other large carnivores. Whilst states would plead that bears area threat to humans, the reasoning is more likely to do with their role as competitors for big game. However, the problems of hunting these animals also have multiple dimensions. Culturally, they hold high significance for many native people who also live in the Yellowstone management area and have not been consulted in the decision to delist bears. Ecologically, there are many issues in play. Bears are, arguably, still in a very vulnerable position in Yellowstone and are dying in disproportionate numbers each year even with the protection of the ESA. For example, climate change induced drought and invasive species have extirpated one of the bears main food sources, the cutthroat trout, as well as damaging other food sources including Whitebark pines and elk. Grizzlys have very low reproductive rates, with huge amounts of parental investment, meaning that they are very slow to react to changes in the environment and colonise new territories. This means that they will feel the pressures of climate change more than most, causing their population to suffer alongside hunting.

My personal bias aside, I feel that there is not a great case for delisting the grizzly bear from the ESA protection. There is a very real chance that hunting would lead to extirpation outside of the Yellowstone management area, where there are no limits in place. Isolating the population within Yellowstone, whilst hunting them as well, could have disastrous impacts on then stability of the population as their numbers dwindle and their genetic diversity lessens. Let me know your thoughts below, but I feel that there is no necessity behind this law change, simply a demand for blood.

Could the removal of the 'ESA Safety Net' mean extirpation for Yellowstone's grizzlys?; Source.

Merry Christmas from the "Santa Spider"

Merry Christmas to all my readers! I hope you're all enjoying a good festive break from work, university and life. Whilst I'm sure you all have better things to do today than read my blog, I thought I would bring some ecology in to your day if you're up to it! The spider below is colloquially known as the ladybird spider or 'Father Christmas' spider, which as you can probably guess, is due to the bright red, white and black markings found on the males. It's one of the UK's rarest and smallest spiders and suffered from habitat degradation throughout the 20th Century.

Eresus sandaliatus, apparently trying to sniff out a female with organs on his legs; Source.

The spider is somewhat of a conservation "Christmas miracle" and has been brought back from the brink of extirpation in the UK to a now thriving population. The spider went from an estimated 50 individuals remaining in Britain in 1993 to well over 600 in 2000. The spider makes its home in heathland, which is one of the UKs most threatened habitats, and over 90% of it has been lost to development and agriculture since 1800. In Dorset, there has been concerted conservation efforts to restore the spider populations as well as protect heathland habitats. At one site there were only 7 spiders left, but there are now thriving and have been released from this site into other areas, where they have successfully colonised. Workers from the RSPB used plastic water battles filled with moss and heather to create houses for the spiders where they could breed safely.

A cute and inspiring conservation story - I try not to be too pessimistic on this blog!

 Merry Christmas!

Tiny spider is tiny; Source.

Plastic water bottle houses, Source.

Look Deeper: Extinction Risks to Soil Biota

Earlier this week, we celebrated World Soil Day (4th Dec). One of the key themes in this years festivities was to highlight the need to increase research into soil ecology and underground ecosystems. In particular, to warn of the potential underground extinction risks that we have an very limited understanding of. A new collection of papers has been published in Nature as part of World Soil Day to highlight these issues among other soil related discussions. So, in accordance, I will be bringing these issues to my blog to give us all an education about soil ecology, as despite the relative neglect compared other areas of ecology, the soil and its biota are fundamental components of all terrestrial ecosystems.

In order to form conservation approaches for underground ecosystems, we need a clearer understanding of the diversity and functionality of them. We know that soils provide vital ecosystem services, particularly for agriculture, so there is clear motive for conservation action - regardless of a lack of moral motive, as concern for things small and dirty tends to be less. The extent of biodiversity below ground is hugely unknown, partially due to the impracticalities of studying these organisms due to their size and inaccessible habitat.  As shown in the graph below, taken from one of the new papers, the vast majority of what lives in the soil is under 1mm in size. What the graphs also shows, however, is the extreme abundance of these organisms - over 1kg of bacteria per meter squared is an insane amount of individuals! Aside from our poor understanding of the diversity, other challenges for understanding potential extinction risks include the lack of suitable models, the complexity and density of microhabitats within the soil and uncertainty about temporal and spatial scales. I'm not going into these here, but they are all detailed here if you're interested!

Soil biota, shown by coloured crosses, are generally very small and very abundant ; Source. 

The most important extinction risk factors for soil organisms are not dissimilar to those faced by their terrestrial counterparts. Habitat loss, a concept we are all familiar with in relation to aboveground organisms, can cause equal disruption for soil ecosystems, for example through the fragmentation of the soil surface via urbanisation. This has been shown to link to declines in abundance of nematodes and other soil biota. Equally, climate change and global warming pose a threat just as they do to terrestrial and marine biomes. Extreme drought events can cause devastation of soil based habitats, for example. Climate change is also thought to have some more complex impacts on soils which can be equated to habitat loss, due to the degree to which the soils are changed. It has been shown that the increased atmospheric CO2 concentrations lead to a reduction of nematode diversity due to the loss of pore spaces in the soil which are required by the organisms. Soil habitats are also impacted by agricultural practices, such as tilling, irrigation and fertilization which impact both soil structure and composition. It is thought that these factors drive constant habitat loss for components of the subterranean community. Although it is difficult, as mentioned above, to know the extent of these impacts, we do know that many of the susceptible species, such as earthworms and mycorrhizas, are of major functional importance to their own ecosystems and ours. There are also potential risks from invasive species, but at a microbial level more than invertebrate, which have likely been spread as a result of travel and tourism. Many of the soil biota are highly specialized in their niche, which is commonly considered to make them more vulnerable to both invasions and extinctions.

So there are considerable risk factors stacked up against soil ecosystems, much as there are against the terrestrial. There has, unfortunately, been very little conservation action in comparison. Some studies have already documented local extinctions of earthworms and various fungi due to the factors discussed above. So perhaps we should start taking some action? This, if any, is a good time to start. 2015 is the International Year of Soils, as declared by the UN General Assembly, after-all. This declaration was made with the intent to raise awareness of the life-supporting functions of soils and to promote the importance of soils in achieving a number of the new 17 Sustainable Development Goals. I hope that you've learned something about the oft-neglected but important goings on beneath our feet, and that in future you might give them a thought in conservation discussions.

Happy World Soil Day! 

Worrying Predictions for the Amazon

Earlier in the week, a massive review paper was published by 170 authors from 102 affiliated institutions. The paper estimates and assesses the extinction risk of over 15,000 Amazonian tree species and produced the fairly alarming figure that 57% of them qualify as globally threatened under IUCN Red List criteria. Furthermore, they predict that the trends observed in Amazonia apply to tree throughout all tropical biomes and that likely over 40,000 tropical tree species worldwide would  qualify as globally threatened on the same criteria. The study has gained quite a bit of media attention for its 'shocking' claims that over half of Amazon tree species are going extinct, including coverage in mainstream news outlets such as the BBC and The Guardian. As we discussed in Part 3 of the 6th Mass Extinction, this can be an important way of communicating the severity of anthropogenic extinctions to the public.

Closer examination of the paper, however, reveals that some of its claims are not quite as dramatic or eye-catching as the media would make out. The 57% figure comes from Business as Usual (BAU) scenario which estimates that by 2050 40% of the original Amazon forest will be destroyed. BAU is commonly considered "worst-case-scenario" in environmental models, so we cannot take this as what will happen. An improved governance scenario (IGS), which estimates forest loss by 2050 at 21%, suggests that only 36% of species will be threatened. This is perhaps a more realistic (hopefully) estimation, as we know that governments and international bodies are working towards improving management and conservation of tropical ecosystems.

Results of the new study, showing the severity of a BAU scenario; Source.

Importantly, the paper highlights the urgency with which we need to address these projected losses in order for them to be prevented. It shows that protected areas in the Amazon are likely to be a successful way to protect populations if these areas to do not suffer further degradation. Clearly, improved governance has the potential to reduce species loss dramatically within the next 35 years, and this paper and the message it carries has come just in time to help highlight this at the COP21 later this week.

Are We Mass Murderers? Earth's 6th Mass Extinction - Part 3: Implications

The third and final entry in my discussion on whether or not we are entering a 6th mass extinction event. In this post, having got all the complicated stuff out the way, I will be discussing the societal implications of the 6th Mass Extinction as a concept and also the message we need to be taking away from this research, regardless of a definitive 'yes' or 'no' answer to the question. I hope you've enjoyed the journey and I would be really interested to know if your opinion on the 6th MEE has changed throughout it, let me know in the comments :)

If you missed them, check out Part 1 and Part 2!

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The results of the poll that you, my lovely readers, have been partaking in over the last few weeks show that really, we're all a bit confused about what's going on but we know it's something significant. To be fair, I think that quite adequately sums up how the academic community feel as well. There are a lot of big unknowns and uncertainties in the data, as discussed in the previous post, which have led to a lack of definite answers about extinction rates and extinction magnitude. Some of this can be improved by collecting more data on currently understudied groups, especially invertebrates - reminder that only 1% of bivalves have been assessed by the IUCN! However, there are many, many unsolvable issues with fossil data as every good palaeontologist knows, we can extrapolate and model and adjust for bias to our hearts content, but there are some species we will never know about and we will never know exactly what happened to them and their relatives. There are inherent problems with comparing data gathered in completely different ways and from animals in different states of existence, so perhaps the question is simply one we cannot easily answer. I pose a new question to you - does this actually matter? Does it matter that current extinction rates don't quite fit with the technical definitions of a mass extinction? We are well aware from the data of the abnormality of current extinction rates in comparison to natural variability through time, and well aware that we hold the majority of the blame for this. Do we need a dramatic title for it?

Your votes! Homegrown data.

In some ways, the answer is yes. It's a kind of depressing yes. If you Google "6th Mass Extinction", you will be greeted by a plethora of sensationalist news articles claiming that the 6th MEE has begun , and more importantly, will humans survive it?! Humans tend to care more about things when humans are involved, as we have demonstrated time and time again throughout history. If we look in the comments on some of these articles, readers actually don't seem to be getting the message that we need to change our collective behaviours. See the enlightened comment below from a Daily Mail reader, sporting the 2nd highest amount of up votes on the article:

"Whatever changes the climate may experience, the consequences will pale into insignificance compared to the catastrophe resulting from massive unrestrained population growth in the developing world. Open borders will make this our problem too"

Bringing it back to humans, with a hint of UKIP. Daily Mail readers aside, if you ask anyone in the street, they would probably say that of course they are aware of humans causing extinctions, but do they understand the extent of the problem? Probably not. Education, if you can call it that, through sensationalism is one way to get the message to the wider public. However, as the above shows, we need to be doing this in a more effective way. If scientists did agree on a technically defined or supported 6th MEE, then perhaps it could be something that got more serious journalistic attention and much needed political attention. Social scientists have suggested that "inadvertant envrionmentalism" is the way forward, as often there is a gap between our values, however sincere, and our actions. They advocate that government policies, such as limiting deforestation in this instance, as they have the power to change behaviours without the need for values. This is one way in which mainstream attention to a dramatically definite 6th MEE has the power to help. If we want to be more optimistic and think about changing values via awareness, Racing Extinction and the #StartWith1Thing campaign is great example that again relies on the sensationalism associated with the 6th MME (The working title of the film was 6!).

Sensationalist and melodramatic representation of the 6th MEE, could it be useful?; Source.

In others, the answer is no. In light of the sheer numbers of species lost, and the potential there is for that to increase in coming years, what we need to be thinking about are urgent conservation measures. As multiple papers have highlighted, the extinction rates and magnitude is likely to increase as years, and harmful anthropogenic practices, continue. In particular, Barnosky et al. highlight the destructive potential  for synergy between co-occurring environmental factors such as atmospheric composition and unusual climate dynamics, similar to how co-occurrences of bolide impacts and flood basalt volcanism have interacted dangerously in the past. Without mitigation of these unnatural factors, particuarly pollution and CO2 levels, extreme ecological stresses will be placed upon most living species, especially given the feedback of individual stressors. Ceballos et al. point out that, in human timescales, the loss of these species and the ecosystems services they provide would be effectively permanent. They argue, as do Barnosky et al, that avoiding a biodiversity crisis (regardless of what it may be called) requires rapid and greatly intensified efforts to alleviate pressures on endangered species and protect them from exploitation. Many of the pressures are intrinsicly related to population growth and economic inequalities, and have the potential to threaten humans alongside other species.

Are we going to run ourselves into the ground? Let me know your thoughts in the comments!; Source.

In summary, it is debatable whether or not the 6th Mass Extinction being confirmed matters, but there is one thing that isn't debatable, and I will leave this as a closing thought for you:

The window of opportunity to act is rapidly closing and with the COP21 talks starting in under a week, it is imperative that we are mindful of the extent to which we have affected global biodiversity and will continue do whilst CO2 levels continue to rise and corporate greed is placed above moral concerns.

A sad loss and a straw in a nose

Earlier this week, an 813-pound sea turtle was found dead off the coast of Massachusetts, which likely died from injuries caused by marine fishing gear, despite the use of turtle exclusion devices in many commercial fisheries.  The turtle was a leatherback sea turtle (Dermochelys coriacea), which is both the largest living turtle and a spectacular animal that we have reduced the population of, to the point where it is classified as Vulnerable by the IUCN. There is, however, a definite potential for the decline of this and other turtles if we do not step up to the mark in terms of conservation practices and multi-disciplinary approaches.

Aforementioned turtle :(, Source

The leatherback sea turtle provides a perfect platform to discuss a variety of human impacts on marine ecosystems.  One of the biggest threats is the commercial fishing industry, many turtles are caught as bycatch, approximately 1500 mature females alone in the eastern Pacific in the 1990s. Turtle excluder devices are ineffective with mature adults, as they are actually too big to get through the holes intended for their escape. Their pelagic lifestyle makes them common bycatch for vessels fishing for tuna swordfish and sharks, as the congregate in the same areas of upwelling that the leatherbacks use to feed. The turtles, being marine reptiles and not true fish (But seriously, let's not go there about what type of reptile they are - I had to write a paper on that last year. If you're interested, see a variety of papers with awful, awful names), need to return to the surface to breathe and often drown as a result of being caught up in the nets.

Second on the list is habitat loss. Sea turtles are hugely dependent on beaches for nesting, and although not as often as other turtles, tend to return to their own hatching beach. A variety of typical anthropogenic crimes on the environment: sea level rise, mass tourism and unconstrained coastal development, litter and pollution and others have disturbed and even completely destroyed some crucial turtle nesting beaches around the world. It is unfortunate that many of the areas where the turtles nest (Malaysia, Brazil, Costa Rica, Carrbiean Islands, etc) are all popular tourist destinations for the very beaches the turtles need. The coral reefs as well,  which are important feeding grounds, are suffering extensively as a result of bad tourism practices in many Caribbean countries. Many of the beaches also experience widespread illegal egg take, which seriously hampers leatherback numbers and distorts the natural sex ratio. A recent study  by Ohiana et al. discuss the viability of conservation options in regards to protecting the the nests of leatherbacks in the Dominican Republic. In the Dominican Republic there have been protection measures in place since 1974, but there is still an on going battle to protect the turtles. At one beach, clutch relocation has been in place since 1974 and is still assessed as the only viable option for the area, due to the sheer scale of the illegal poaching. Other beaches have had to implement less drastic measures, such as artificial incubation, but as the paper summises, community engagement and enforcement is needed in order to improve conservation measures. If we want to move towards more sustainable intervention tactics, the locals need to work with the scientists.

The final threat I will mention (but trust me, there are plenty more) is the often fatal impacts of pollution, both chemical and physical. Many turtles die from internal injuries and blockages caused by the ingestion of non-digestable material, such as a plastic bag which the turtle mistook for a jelly fish. Chemical pollution as well, impacts the viability of leatherback eggs, with high levels of the plastic compounds being measured in the yolks of their eggs. 83% of all sea turtles sampled in a recent study had ingested anthropogenic debris, of which plastic was the most prominent component, accounting for 95% of the dry weight of the total ingested material. This study highlighted out lack of understanding about the mechanisms which affect the dispersal of anthropogenic debris around the oceans and how these turtles end up ingesting it. To really ram the point home, and make you feel a bit bad for every McDonalds straw you've ever discarded carelessly, please take a look at the video below - a very real example of what can happen as a result of our carelessness.

EDIT: Here is a link to the GoFundMe page of the PhD Researcher who narrates in the above video, if you're interested in her work, take a look!

Invaders: A Response to Thomas and Palmer, 2015

Recently, a number of studies have highlighted that whilst we are suffering global biodiversity losses, local diversity is actually relatively stable, or in some cases increasing. This is due to a number of reasons, including increasing habitat heterogeneity and crucially the spread of strong generalist competitors. In the analysis conducted by Vellend et al., they found that whilst post disturbance was the only truly positive driver of vegetation change (as we would expect in accordance with the intermediate disturbance hypothesis, on which much of our conservation practice is based), invasion was the only factor which stood out as driving a decline in diversity.

Postdisturbance promotes diversity, whilst invasion seems to limit it. Source: Vellend et al., 2014

However, it is arguable that as the error margins cross zero, it is weak evidence for the derogatory effect of invasive species. Indeed, recent thinking has been that the impacts of invasions are not as significant as we have traditionally thought. Often primary production can be enhanced, and resident species do not always decline, overall less than half of the impacts were found to be statistically significant.  The study which this post focuses on, published earlier this year, focuses on the impact of invasive plant species in Great Britain. Across 479, sites, Thomas and Palmer found that diversity had actually increased, and that the negative impacts of invasive plants on British biodiversity had arguably been exaggerated.

Increased diversity of native species with non-natives, Source: Thomas and Palmer, 2015

Whilst their data is sound, I am inclined to disagree with their sentiment. Invasive species, particularly fauna but some flora as well, have had well documented negative impacts on native British ecosystems. Overall diversity can be a very crude measure of the health or success of an ecosystem, the composition is far more important - particularly if we are looking to safeguard our native biota. Yes, there may have been an increase in biodiversity, but is it the biodiversity we want? These patterns are not unexpected, invaders are particularly successful in frequently disturbed areas, which are also likely to be diverse areas due to the variety of niches to be exploited by fast growing colonisers. Indeed, if these areas are regularly disturbed, it will likely prevent competitive exclusion by the invaders and maintain diversity. This kind of ecosystem is far removed from our native climatic community of oak woodland. Perhaps I'm old fashioned, but I believe that our goals in conservation should be to maintain these native conditions as much as possible, rather than simply to maximise diversity.

Many examples of invaders, outside of the infamous grey squirrel, exist and are key issues in current British conservation.  The American Mink, which has all but wiped out our native Water Voles - diminishing populations by up to 94%. The signal crayfish, larger and more aggressive than to our native white clawed crayfish, are estimated to have reduced native numbers by 95%.  The aptly named Killer Shrimp spreads rapidly throughout freshwater ecosystems and has been shown to drastically decrease invertebrate and fish diversity, leading to simplification of food webs. Plants, as well, have had severe ecological consequences as invaders. Top of the most wanted list is Japanese Knotweed, which overruns fluvial ecosystems as well as much of our urban environment. There is even an invasive mouse which eats the chicks of a critically endangered Albatross species alive, documented in the British Overseas Territory Gough Island. The list goes on. The point is that there are many, many species which have and will have severe impacts on our native biota. The local lens must focus on what is actually happening in these local ecosystems, and we should be aware of what is happening to British wildlife before accepting sweeping generalizations that invaders have "no negative consequences for native diversity".

Purposefully evil looking pictures of invasive species

Habitat Fragmentation 1: The Need for Otter-ly Integrated Aquatic Systems

Habitat fragmentation is among the most blatant and well documented human abuses of our environment. The science behind it is not difficult to get your head around either - ever more isolated populations of both plants and animals are much less able to mingle with other populations and are therefore vulnerable to local extinctions (or extirpations). Simple metapopulation dynamics! There are many stories to tell about which species have suffered from this, and in a series of posts I plan to share a few of them, perhaps those which are not as immediately obvious.

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Eurasian Otters (Lutra lutra) are among Britain's cutest and most loved species. They suffered a very well documented and publicized decline throughout the latter half of the 20th Century, largely due to pesticide use, hunting and habitat loss. Thankfully, due to the ban of some of these pesticides and the implementation of conservation policies in the 80s and 90s, Otters have recovered from near extinction in Britain. As of 2011, Natural England announced that they were once again present in all English counties.  Hooray! But what do they have to say about habitat fragmentation?

Otters provide a perfect example to support the argument for landscape scale ecology, and conservation approaches that consider freshwater systems as an integrated whole.  Otters, among other creatures, utilise all components of the freshwater landscape: ponds and rivers, lakes and backwaters. In a study of the River Glaven in Norfolk, a well kept and highly interconnected river, droppings from the recovering otter population were found in a variety of freshwater habitats - showing distinct patterns throughout the year. In the summer, otters primarily fed on fluvial creatures such as the white clawed crayfish, but during the spring and winter, whilst the crayfish were hibernating and amphibians breeding, their diet consisted of >70% of still-water creatures. The study found evidence of otters in ponds over 1km away from the main river, which shows that even seemingly detached bodies of water are indeed integrated.

Map of otters in the River Glaven catchment, source: Sayer 2014

It is arguable that the otter populations in Norfolk would not have recovered as successfully if the habitat had been more fragmented. It is not only the otters themselves, relying on the ponds to feed them in winter, but the myriad of invertebrate and amphibian species that rely on the existence of a metapopulation to stabilise their demographics. Among those pond inhabitats with metapopulations are Great Crested Newts, Crucian Carp, dragonflies, mayflies, caddis flies... anything from a pond which ends in -fly really. All of these animals and the plants they feed on need a highly connected habitat to support their metapopulations and in turn they stabilise the ecosystem and support fluffier and more high profile predators like the otters. This is the case with any habitat, not just the ponds of Norfolk and as we considered the global picture of environmental change, we must not forget the little guys on the front lines that hold everything together. To those who are opposed to landscape scale ecology....

Upset Otter, source: QuickMeme