The new blog!

To all followers, thanks very much for reading my stuff this far. I’ve managed to organise a group blog now over at www.forstarsandbeetles.com where all new posts will be located, along with various associates from other environmental/biological disciplines (for some reason although the url is correct, the link doesn’t seem to work, sorry! Damned wordpress: copy and paste it, that works fine) Hopefully we’ll give a good variety of material, often enough to keep you entertained and interested.

So stop reading this boring explanatory post, go over and get reading 🙂

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A Mada who-hah

Deforestation currently seems to be an inevitable consequence of increases in human population. As the number of people goes up, so does the area of land humanity requires to live on.

This is particularly true of places where people live at a high density: crowded areas need more food, fuel and timber to sustain the population within it. As in many tropical regions the transition from the traditional high birth and death rate to a lower one is not complete, and they are seeing a wonderful decline in infant mortality combined with a relatively high birth rate. This is contributing to the alarming increase in deforestation worldwide, being estimated at 13 million hectares annually.

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Death from below, 2013

Bats. You know what bats are right? The little weird creatures that live in your roof, and fly around at night? Harmless beings, that just feed on mosquitoes, moths and other invertebrates that people generally (sadly) don’t like.

Well, that’s not strictly true. Latin America’s vampire bats are likely the most infamous exception, landing on mammals and birds, and then sucking the sleeping animals’ blood. Awesome, fascinating creatures; but certainly a little creepy.

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Some species of bats manage to fish. Using echolocation they are able to detect ripples being formed on the water’s surface to alert them to their prey’s presence, before swooping down and catching them with a specialised pouch between their legs. And so a creature from an entirely different habitat is caught unawares, and dragged into the air to die.

More pleasant are the fruit bats, or ‘flying foxes’, which can have wingspans of up to 1.7m wide. Rather than catching prey they feed instead on fruit and nectar, flying around forests pollinating and dispersing seeds. In some old-world forests, they are considered vital for the overall ecosystem’s health through offering these services.

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Perhaps less known is the Greater Noctule, a rare bat species found around the Mediterranean. Quite large for a bat species found outside of the tropics; adults have wingspans of up to around 45cm across-considerably larger than the ones commonly seen flitting about in British summers. The wing’s physiology suggests that they hunt by chasing down prey on the wing.

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Unusually, it seems that this prey is not invertebrates, but birds. There are some bat species that specialise in catching their prey (mostly invertebrates) by ‘gleaning’-pulling them off of leaves. Some of the larger gleaning species have been found to occasionally take small birds when they sleep in sufficiently exposed positions.

But the Greater Noctule is different. Found in areas which act as corridors for migratory birds, they receive a food bonanza in spring and autumn every year. Huge quantities of small birds fly over their habitats at night, and no other nocturnal predators have the necessary adaptations to catch them.Image

It seems that they feed primarily on birds; particularly Robins and Wood Warblers whilst on the wing, by chasing them down. Similarly when feeding on invertebrates, the bats don’t even need to land to feed on their feathered prey but eat it whilst in flight; all the better to catch more.

As the bats hunt at night and their prey are species that depend on sight as their primary sense, they are thus able to ambush them with ease, bursting out of the gloom. The sound the bats emit in their echolocation is outside of the birds’ hearing range, so it is likely they have no knowledge of their danger until they are caught.

During migratory periods birds may make up 78% of the bat’s diet, a phenomenal switch from the summer periods when there are no migratory birds, leaving them to feed on invertebrates instead.

This may sound an exotic phenomenon, but whilst the bats themselves live outside of the UK, the birds affected do not. One of the main species found to be affected, the Wood Warbler, migrates to the UK from northern Africa every spring, and then returning in autumn. Birds that we see in the summer may have run a gauntlet of carnivorous bats. Britain’s Robins are not migratory, but ones from Scandinavia do migrate, and so the cousins of the Robins you see in your back garden may meet a bizarre end in the jaws of a bat.

Let it not be said that nature doesn’t have a sense of irony, however. As with other bat species, many Greater Noctules in turn meet their end at the talons of a Tawny Owl.

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References :

Dondini, G. & Vergari, S., 2004. Bats: Bird eaters or feather eaters? A contribution to debate on Great Noctule carnivory. Hystrix It. J. Mamm, 15(2), pp. 86-88.

Ibáñez, C., Juste, J., García-Mudarra, J. L. & Agirre-Mendi, P. T., 2001. Bat predation on nocturnally migrating birds. PNAS, 98(17), p. 9700–9702.

Popa-Lisseanu, A. G. et al., 2007. Bats’ Conquest of a Formidable Foraging Niche: The Myriads of Nocturnally Migrating Songbirds. PLoS One, Volume 2.

Photos (in order) by myself, littleREDelf, two by Wikimedia commons, and DarrelBirkett

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The future conservation value of organic and GM agriculture

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Organic food seems to have an overwhelmingly positive reputation in the west. Better for wildlife, better for those eating it, other than a slightly higher price what could you possibly find not to like? On the very face of it, nothing. But begin to use some joined-up thinking, and they’re not quite as benign as may be first thought. There have been a few reviews of intensive, GM and organic agriculture coming online recently, here I’m going to give a biodiversity and conservation perspective, as this is my main background.

Organic and traditional-style farming are known to be at their most beneficial for wildlife in areas where agriculture has been occurring for thousands of years (I.E. most of Europe, parts of Africa and Asia, and I believe some areas of the Americas). Local flora and fauna have had time to adapt the predictable seasonal cycles and environmental conditions that these systems entail, and so thrive with them as a result.  Otherwise, they are greatly reduced in numbers by the heavy use of pesticides, herbicides and fertilizers that are used in ‘intensive’ agriculture.

In areas where agriculture is a much more recent development (for example, New Zealand) the benefit from organic is less, as the local wildlife is less adapted to agricultural conditions, and so it is inevitably harmed when farming takes place-though of course not to the same extent as whilst being blasted by agricultural chemicals on the side.

But as the reader is likely to be from areas where agriculture has a long history, and so as organic food is in your eyes clearly superior for conservation, why should you care about this non-issue?

It’s been predicted that between 2005 and 2050 global crop demand will have increased by 100-110%. I know, I know, if we all reduce our meat consumption then this figure will plummet, but the simple fact is that there is no sign of this happening-in fact global meat consumption is increasing.

In light of this rise, the fact that organic has been shown to be around 54% less productive than intensive agriculture is a real problem. To use ballpark figures, to have a world fed by organic agriculture in its current state requires twice as much land devoted to agriculture. That’s a real problem when in recent decades roughly 80% of new cropland was claimed at the expense of tropical forests, one of the habitats conservationists are rightly particularly keen to protect. To meet the world’s projected food demand by 2050 without intensifying agriculture will require humanity to clear around 1 billion hectares. With intensification of our food supply, this could be reduced to 0.2 billion. That’s a lot of high-quality habitat conserved at a stroke

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With this in mind the simple ‘organic=good for wildlife, intensive=bad’ mindset is exposed as misleading. Whilst in western countries it causes local rises in biodiversity, this can be viewed as being to the detriment of tropical ecosystems, an effect which is accelerating annually with population rises in tropical regions.

The issue is of course not a simple one, however. Agricultural chemicals can have many severe environmental effects, both on wildlife and people. Though of course we need to feed the world, and do it in an informed manner, doing so in an environmentally degrading way is unwise.

This is why I favour a shift to the use of genetically modified crops-GMOs (GM livestock is an issue that I’m not going to go into here). Many GM crops require far less fertilizer, pesticides and herbicides, and so would have a lower environmental impact than our current agrichemical-heavy system, whilst maintaining that all-important high crop yield.

This is controversial for many environmentalists, but why exactly? After many decades of use worldwide, there remains no sound scientific reason for believing that GMOs have any impact on human health, and why should they? Small changes in a plant’s DNA simply alter it’s physical form very slightly. Mildly altered DNA is broken down in your body just the same as unaltered DNA. As a lot of GMOs are the result of inserting a gene from edible plant A into edible plant B, suggesting that they will be harmful is akin to saying that it’s perfectly healthy to eat a horse, and a donkey, but the DNA of a mule is somehow dangerous.

Mostly these fears seem to be simply a result of a lack of the understanding of science, and play on fears that humanity is ‘playing god’. I’m sure people once thought that vaccinations were ‘playing god’ too, as they are indeed ‘unnatural’. But lives saved with negligible side effects are really not something to be sniffed at, regardless of any misplaced distrust in your notion of ‘scientists’. (I’d like to point out that Mark Lynas recently gave a talk on this matter, which is well worth checking out if you have the time).

Environmentalists (and I count myself as one) rarely discuss GM without quickly bringing up Monsanto. This seems completely disingenuous; rather than a coherent point it’s inevitably just a simple play on many people’s inherent fear of big business. Being your good lefty-type person I’m uncomfortable with how much control companies would gain over our food supply. But this ignores a simple point: agribusiness already has a chokehold over the overwhelming majority of our food, and this seems unlikely to change. We may as well allow them to use this power to feed the world at the least environmental impact possible,.

I feel it seems that thus the only reasons to oppose GM are our own perceptions of the inherent moral goodness of organic and GM, which when balanced against the morals of large-scale deforestation in the next few decades seems frankly absurd. Conservationists and environmentalists are usually the same people, but in actively promoting far-lower agricultural yields for conservation purposes at the expense of huge tracts of rainforest, we seem to be cutting off our nose to spite our face.

Follow me on twitter @goldenmole

Photos by Vampire Bear and markg6

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Don’t feed the birds?

Fisheries discards have become a surprisingly hot topic of late. Thanks to campaigns such as Hugh’s fish fight it is now relatively commonly known that around 8% of all captured fish are thrown overboard again, where they mostly then die. This amounts to perhaps 7 million tonnes of fish worldwide per year, a massive and unsustainable amount. It was recently agreed that discarding edible fish stocks will be banned from January 2014, with discarding ‘white fish’ banned from January 2016. Sadly progress in politics takes time.

Perhaps less known is that fisheries discards have actually become a regularly used food source for seabirds. As fisheries have become more intensive the amount of food available to seabirds has increased, reducing their numbers worldwide. This has been a double edged-sword however, as fishing boats subsequently provide a source of food via the discarding of bycatch, which is comparatively easily found due to the conspicuousness of a boat compared to small (underwater) fish.

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Fisheries discards may have helped to limit the decline of seabird numbers, perhaps even artificially elevating that of some scavenging species, like gulls and skuas, which may actually have higher populations as a consequence of discards than would have been the case in the absence of fishing.

So what are the likely consequences for seabirds of banning the practise of discards? This is the subject of a new paper, in Journal of Applied Ecology, focusing particularly on seabirds that spend at least part of their lives in the waters of the EU.

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For birds that feed entirely on fish, but do not specialise on particular fish species (for example gannets and some shearwaters) the impact will be unclear. The birds may be able to simply change their foraging strategy to catch live fish again; the issue is whether there will be sufficient fish left to sustain the current seabird populations. It seems reasonable to expect that they will suffer some sort of decline, as they simply will simply suffer a reduction in the availability of food.

Perhaps more complex are the generalist seabirds who do not simply rely on discards, or even rely purely on going to sea to obtain food; the generalists and scavengers. A bird of particular interest is the skua-as well as feeding on discarded fish, they also steal food from other birds, and even eat smaller birds. In fact, skuas have been found to consume over 47,000 seabirds around the isle of St Kilda (Scotland) alone. One worry is that as fishing becomes more difficult, skuas will start predating on small seabirds more. These smaller birds will already likely be suffering because of a reduction in their food supply, if this is coupled with an increase in predation their numbers could be hard-hit, as they are damaged from both sides.

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Perhaps the only saving grace for seabirds is that when boats stop throwing dead and dying fish overboard, it is likely that birds will stop seeing them as a source of food, and so will be less likely to associate with them, reducing the numbers drowning in nets. It is currently too early to speculate if the reduction in premature death by drowning will mitigate the loss of food, however.

Please note though, dear reader, this is not a blog defending discards. Throwing away such a high proportion of captured fish, simply for them to die anyways is illogical and damned unsustainable. Global fish stocks are declining on the whole, and we need to learn to better use what we catch. Over 1 billion people currently rely on fish as their main source of protein, so this is a resource that we must manage with care.

This is however a regular theme in ecology-changes in humanity’s policies affect the natural world in numerous ways, many of which are difficult to foresee. There is very little that we do that is without consequence: whether the initial large-scale reduction in fish stocks, or our tweaking of our actions subsequently. It is the place of ecologists to attempt to study these impacts, so that we may better predict the impacts of our actions in the future. It is hoped that other fisheries will enact anti-discards policy in the future, hopefully studies predicting the consequences, and later measuring them, will help any future conservation efforts, and maybe help humanity manage the world that little bit better.

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Photos, in order, by Shaylamaedavid.ian.robertsDirk Roorda and Pétur Gauti

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Those firey bodies

Strange beings lurk in the deep sea. Weird life, unlike anything found near the ocean’s surface, and bizarre enough to make anything lucky enough to be dwelling on land spit out its morning coffee in disgust.

A pretty high proportion of this deepwater life glows. In areas of the ocean termed ‘mesopelagic’ (between 500 and 1,000m deep) there are no obstacles to hide behind, no floor to hide on, and yet some weak downwelling sunlight ensuring that complex beings need to retain some level of vision to survive. This combination of characteristics makes bioluminescence a particularly valuable tool, both for concealment, communication and combat (Young 1980). All known bioluminescence is either produced by bacteria housed within the animal in question, or produced by specialised organelles of the animal itself.

My current research involves just this; looking into how Pyrosomes bioluminesce, working out what makes them glow.

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Pyrosomes are a colonial animal, meaning what you see in the image above is a colony of tiny individual animals, all stuck together. Each of these animals is called a zooid.

There are eight known species of Pyrosomes, all of them forming colonies shaped like long tubes, closed at one end. Each individual zooid sucks in water from the outside, at the top of each zooid you see in the image below.

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This water is then passed through the feathery structure you see underneath, where they filter out any food particles, before expelling it into the hollow inner of the colony. The combined force of the water from each zooid being ejected into this cavity and so out of the colony’s rear thus propels it along, in a wonderfully simple coupling of both feeding and movement.

Pyrosomes are known to produce one of the most spectacular bioluminescent displays of any animal; upon seeing them in 1849 the great Thomas Huxley was moved to write “I have just watched the moon set in all her glory, and looked at those lesser moons, the beautiful Pyrosoma, shining like white-hot cylinders in the water.”

Despite the beauty of the blue-green flashes that these animals produce, little is known about how it comes about, perhaps simply due to their obscurity (every time I tell another biologist what I’m studying they inevitably say ‘what? What’re they?!’), and so they are little-studied.

Each zooid has a light organ flanking the siphon on their exterior, but strangely these are not neurally connected to the brain. Instead, when the zooid is stimulated either by light or physical movement, the tiny hairs in its gill basket cease moving. This reduces blood flow to the light organ, which then begins to luminesce in response. As each zooid luminesces in response to light, a wave of light emission quickly travels through the colony, sustained for many seconds.

Because the gills of all the zooids in the colony have now stopped sucking in water, the colony begins to sink. Pyrosome colonies are often found in groups, and so any nearby will begin to luminesce and sink in turn, in a signal passing through the group. This is both incredibly simple and very effective at helping them either avoid areas with lots of sediment in that would clog their gills, or deter predators-your prey suddenly glowing blindingly all around you is enough to scare most away, having been lit up to any larger predators with a flash that may as well sound ‘dinner!’

However we still don’t know how Pyrosome light organs actually work, simply that when given the signal, they light up. This is what my research is looking at-trying to define if they house symbiotic bacteria that bioluminesce, or if the light organs contain organelles that luminesce; as seen in many fish.

The light organs have been found to use enzymes similar to those found in Photobacterium; a common light-emitting bacteria, but they have very different appearance to any known bioluminescent species of bacterium. Attempts to grow these cells outside of the light organs have failed, which may indicate that either they are bacteria so specialised that they can only live inside their host, or that they are in fact organelles.

If they are bacteria, that they look very different to all known bioluminescent bacteria is unsurprising-as they can only live in Pyrosomes they will likely have been isolated from the outside world for a very long time.

Most of my research is looking at the genetics of these cells, using their DNA to identify if they are in fact bacteria, and if so to try and identify them.

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So why am I looking at this subject? Perhaps one of the main answers, as with most science, is sheer curiosity: there’s a mystery to be solved, and it’s interesting discovering how this works for curiosity’s sake alone. The method Pyrosomes use to control bioluminescence is unknown in any other groups of animals, and so to discover just what it is that they are controlling in this way would help fill a tiny part of the great gap that is humanity’s current ignorance of the natural world.

However such faux-noble reasoning aside, bioluminescence is important to humanity. So important that in 2008 a team of researchers was awarded the Nobel Prize for chemistry for their pioneering series of work on a bioluminescent jellyfish. Through their subsequent work on the protein this jellyfish species uses to luminesce, a wide variety of laboratory techniques have been developed, helping scientists to discover many new phenomena, and help develop treatments for many diseases. Though it would be quite optimistic to expect this research to spawn such a grand legacy, this sort of curiosity-driven work is at the root of innumerable scientific advances.

So who knows, perhaps these bizarre creatures from the deep may save us all.

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First photo by Nick Hobgood, all other photos by myself.

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The fate of the Saiga

Saiga are medium-sized antelope, found in the plateaus of central Asia. During the Pleistocene (aka, from about 2.5 million years ago until just 12,000 years ago) they were found all the way from the UK; east until Northwestern Canada. In more recent years as the earth’s climate warmed their range has shrank significantly, as their steppe habitat has shrank.

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The animals take part in colossal migrations, often travelling up to 120km per day when moving between their summer and winter pastures-not bad for an animal only 60-70cm tall at the shoulder. It’s thought that this is why they have their characteristic large, flexible noses: herds of many thousands of animals travelling at this pace across dry plateaus kick up a lot of dust, and so their noses may be specially adapted to prevent them from choking on it.

Like many species of mammal such as the perhaps more familiar Deer etc, Saiga ‘lek’: where a male defends a group of females from rival males, and then fathers their offspring. To defend his harem, the males are equipped with horns, which they keep all year-round. These horns are the main reason why Saiga are currently facing extinction; their numbers down from over 1 million in 1992, to perhaps only 50,000 now.

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In what I fear may become a recurring theme on this blog, these animals are routinely slaughtered for traditional Chinese ‘medicine’. Pre-poaching, males made up roughly 25% of the population, and in the breeding season would be seen defending groups of 12-30 females. Males are now estimated to make up only 2.5% of their tiny populations; so low that females now actually exclude other females from mating with them. As a result, the number of calves born per year has plummeted, and if the trend continues they will likely go extinct. That this is occurring is made even more surprising because unusually among antelope, female Saiga are able to reproduce when they are only a year old. This coupled with the fact that females routinely produce twins means that under normal conditions the animals would be very resilient to extinction, producing huge amounts of offspring every year. As it stands, they are designated ‘critically endangered’ by the IUCN, and as such are of extreme risk of extinction in the wild.

In traditional Chinese-style medicine powdered Saiga horn is thought to have a variety of beneficial health impacts, including the reduction of fever. Though this is known to be medically incorrect the belief persists, with some poor-quality ‘research’ backing up the claims for efficacy.

Clearly the best way to reduce the killing of males for their horns is to reduce demand, perhaps by educating consumers to the inefficacy of such treatments, but too often these attempts become seen as an attempt by ‘westerners’ to alter a component of a culture which we make little attempt to understand. Even with facts spread about the fallacy of these treatments it may be useful to draw parallels with ‘alternative medicine’ used in the west, such as homeopathy: though users are frequently confronted with evidence showing many such treatments do not work, they remain stubbornly committed to their use. People routinely trust anecdotal over clinical evidence.

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Attempts to prevent poaching in the field are sadly very difficult for such nomadic animals, so how to best prevent poaching is a difficult subject. Yesterday calls were made in South Africa for debate to reopen on legalizing trade in Rhino horn, potentially meeting demand by humanely ‘shaving’ the horn off of the animals whilst anaesthetised. Whether a similar technique could work in Saiga remains to be seen, though as they reproduce so frequently it would likely not be viable.

Parallels to the trade in protected wildlife for medicinal use are frequently drawn with the trade in illicit drugs-that prohibition may do little to nothing to reduce demand, whilst simply ensuring that demand is met by the black market, with obviously detrimental conservation effects. It thus seems that the only truly effective way to save the Saiga is to reduce demand through some form of campaign of education amongst those who use it. Such a campaign must be careful to not simply entrench existing views, nor to increase any form of feeling of heritage in using such treatments. The notion of this seems ambitious, to say the least.

With CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) currently meeting in Bangkok to address the protection and status of the many of the worlds endangered species, it will be interesting to see if any new measures are taken for Saiga. Though saving them will certainly be difficult, the world would be diminished without it’s huge herds of weird, nomadic goat-monsters, charging across the steppe.

 

 

Photos by ‘belgianchocolate’ ‘USFWS Headquarters’ and ‘digitalmoneyworld’

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