ecology Archives - Page 8 of 10

06/02/201306/02/2013

The Flora of the Future

It’s the year 2050. Several billion more humans occupy the world, and species translocations are by now the norm to mitigate against increased urban sprawl, climatic instability and a sea level now a third of a metre higher. In spite of unprecedented demands on the natural environment, governments have slowly developed capacity for conservation of wilderness and semi-natural habitat. Beyond this even, with the vast majority of the human race by now living in cities and the continued trend of rural land abandonment; restoration ecology has come to the fore at entire landscape and regional scales. The concept of ‘rewilding’ is debated openly amongst politicians and the public – no longer the mere theoretical exercise of academics. The monetary value of ecosystem services is also by now a very real and tangible concept within economic circles, embedded within highly developed metrics such as green-GDP. Despite such positive developments, however, problematic legacies of the past remain. Intensification of agriculture has been unrelenting globally, notwithstanding inroads into adoption of agroecosystem approaches. A transition to truly renewable energy sources is still incomplete and of utmost urgency. One of the most critical questions of all most likely still looms – have we yet done enough to put a cap in the peak of this, the sixth great mass-extinction of life on the planet?

And so, it is within this future and none-the-less challenging world we find the modern ecologist and biodiversity practitioner at work.

What kind of new and useful technologies may exist to help tackle such problems and challenges of the not so distant future? It is interesting to deliberate on one low-tech tool in particular (the so-called bread and butter of biodiversity), which has been with us already for centuries – and that is the humble species checklist. Specifically we take a look at the Flora – and although coverage here is rather phyto-centric, it should be easy to draw equivalents to all forms of taxa, without (too) much stretch of the imagination.

So what is a Flora in the traditional sense, why is this changing, and how will the Flora of the Future look and function? To briefly tackle these first two questions, a Flora is primarily a list of plant biodiversity (either with or without diagnostic characters and keys) within a specified geographic range, be it local, national or at larger scales. Outside of this basic function there are the ‘added-extras’, which may include notes on distribution, ecology, synonymy, conservation status and even ethnobotanical use. Often the assemblage of national-level Floras has proven quite a mammoth task; logistically challenging, fraught with funding difficulties, and above all time-consuming – with efforts spanning over several decades for particularly biodiverse countries. This is all very well, and such traditional Floras have and will continue to serve as invaluable tools. In this modern age, however, change is called for to tackle some common short-comings of the Flora. A considerable amount of valuable information collected by taxonomists and other experts in the production process is typically lost, never making its way into the public realm – and when such publications can easily run to over 20 volumes, it is clear to see the major constraints involved. Another key drawback is the sheer speed at which redundancy can occur. Even before the final volume of a Flora is published, taxa (species/genera/families) covered within the first volumes may have long been ripe for new taxonomic treatment.

The revolution in how biological information is collected, stored and disseminated is already greatly influencing the Flora. One of the most recently initiated national-level projects is the Flora of Nepal project, for which advances in biodiversity informatics have permeated the entire process from preparation to publication. Although the Flora of Nepal will still be published in printed format, a (if not the) main focus will be an E-Flora freely accessible online, which will also greatly expand the availability of information assembled by experts. A simple yet very significant feature will be the ease of portability of numerous volumes to the field in digital format. Though perhaps most critically, the Flora of Nepal will be maintained and updated to reflect new findings – creating for the first time, in essence, an evolving Flora.

Before we really begin to speculate on the form and function of our Flora of the Future, we must first take a look to the current cutting edge of biodiversity informatics. In what must be one of the most significant advances in decades, the cooperative development of the Global Biodiversity Information Facility (GBIF) by many governments and organisations has promoted and facilitated the “mobilization, access, discovery and use of information about the occurrence of organisms”. This centralized repository of earth’s biodiversity is fast set to reach one billion indexed records within a few years from now, fed from diverse sources ranging from individuals to national biodiversity data centres. It is difficult to envisage how the Flora of the Future could in any plausible way side-step such a global network. Whereas floras have traditionally featured a top-down, expert driven synthesis – the Flora of the Future will also no doubt integrate the emergent trend of bottom-up assembly of knowledge – a good example of which is currently purveyed by the Encyclopaedia of Life.

Let’s get back now to our future ecologists and biodiversity practitioners, and take a little look in as they go about conducting their fieldwork. No matter what habitat or location they study in worldwide, they will each possess a small handheld device connected to the Flora of the Future. Automation of species identification by means of this device will have removed a large bottleneck in their work – leaving ecologists to focus on actual ecology. No longer will they be bound to a particular geographic territory due to limited floristic familiarity – we will witness a complete opening of boundaries, and greater migration of ‘western’ ecologists to the frontline of areas of global biodiversity importance.

But just how exactly could such a device work? A potential basis could feature a combination of machine-learning morphometrics and DNA barcoding – two presently very promising tools. For the former, development of algorithms for auto-identification of plant species is already well underway (see for example the Leafsnap mobile app). These function much like facial recognition technology, and through input of a digital scan/photo can pinpoint unique morphological characteristics required for successful classification. A key aspect of machine learning is removal of subjectivity by conversion of shapes into numerical descriptions – no need for argument any longer on just how ‘subglobose’ a feature is; the ball is already in motion towards a predictive and integrative taxonomy. Upon scanning a specimen in the field, an image will be broken down into key morphometric characteristics, and referenced against a large central database within the Flora of the Future. The Flora will prioritize this procedure by first referencing against species known to occur within a certain radius from where the user currently stands (a useful feature in itself!). The ecologist, on the spot, may learn that the specimen has a confirmed match, and proceed to download key local statistics of importance. On the other hand, this specimen may in fact represent an extension of the species known distributional range. The finding, however, of no known match in the database could spell discovery of a new species, whereas a positive match with notably low morphometric agreement may indicate new subspecific taxa or otherwise interesting findings (for which DNA barcoding could be employed for further verification in both cases).

Regardless of outcome, the above three scenarios will have allowed for a real-time and in situ solution to identification of species. The exact significance of this process will not only lie in the freeing up of both ecologists’ and taxonomists’ resources, but in the real-time flagging of new discoveries. As it stands, it is expected that discovery of remaining undescribed plant species will be an incredibly inefficient process (given that 50% of the world’s plant species have been discovered by only 2% of plant collectors), despite the vast number of these thought to exist. A recent study examining the exact inefficiency of the production chain from collection to publication uncovered that “on average, more than two decades pass between the first collection of samples of a new species and the publication of the species’ description in scientific literature”. In other words, a specimen of a new species has physically passed through the hands of many people before the simple ‘discovery’ (perhaps after many, many years in a herbarium) that it is something new to science. In this sense, an important function of the Flora of the Future will be instant recognition (perhaps even while standing in the field!) of a new discovery as just that – which can drastically reduce this presently overblown timeframe and waste of resources.

Getting back to the future for now, we see our biodiversity practitioners and ecologists as key players in the advancement of ecological as well as taxonomic discovery, with a highly efficient yet passive ability for discovery embedded within the commonplace tools they use, as they go about their work. With an entirely streamlined approach to field research, and identification no longer a daunting prospect in the study and documentation of biodiversity, we will eventually see the peak of mass extinction pass, looking back behind us. The challenges of tomorrow are no doubt great, and a renewed vigour for the taxonomic process will be critical for progress on these fronts. The Flora of the Future will for the first time sew a seamless line between ecologists and taxonomy; the essential currency of biodiversity.

Author

Paul Egan: eganp5[at]tcd.ie

Photo Credit

Paul Egan

16/01/201318/02/2019

Another piece in the trophic puzzle

The food chain is a concept that many non-biologists are familiar with. Ecologically-speaking, this should be referred to as a food web, because there is rarely one prey species for a given predator or one predator of any given species.

The biochemistry of metabolism and digestion means we can reconstruct the diet of a member of a given food web with some basic information about the stable isotopes in its tissues and the stable isotope values of the available prey. Simply put, “you are what you eat”. Carbon isotopes generally reflect the “where” of the diet and nitrogen isotopes generally indicate the “what”.

This overview omits several complications. Firstly, the calculation of diet requires a “conversion factor” (trophic enrichment factor or TEF) for any given tissue of an animal. Animal metabolisms tend to retain ¹⁵N, so consumers have greater ¹⁵N:¹⁴N ratios than their prey. Secondly, each tissue is likely to have a different TEF, as it is made to perform a different job in the animal. Thirdly, TEFs can only be derived by feeding animals highly controlled diets, ideally a single food for the length of time it takes for the study tissue to be fully replaced. In the case of teeth and bone, this can be months or even years.

As there are relatively few TEFs available for animal species, many ecologists “borrow” TEFs from other species for their calculations. Having derived TEFs for carbon and nitrogen in badger blood serum, a tissue that is completely replaced several times a month, we demonstrated that badger TEFs differ from fox TEFs. This is important, as foxes are similar in size to badgers and have a similar feeding ecology, and ecologists might be tempted to “borrow” fox TEFs to use in badger studies.

So knowing more about the biochemistry of badgers (in the form of TEFs) will allow us to learn more about their diets. This may be of importance to farmers planning biosecurity measures for their farms, as they will be able to learn if badgers are raiding their crops (in the field or in the barn). It will also help identify when badgers are specialising on different foods and potentially allow farmers to minimise contact between badgers and livestock.

Authors

David Kelly: djkelly[at]tcd.ie

Nicola Marples

Photo credit

wikimedia commons

07/01/2013

City slickers

Typically, when humans and wildlife meet it’s curtains for the latter. Think of all the megafaunal extinctions in the past and the mounting evidence that we’re responsible for an ongoing sixth mass extinction event. Aside from directed extermination we can change the environment over a very short time-scale to suit our needs and other lifeforms are often left playing catchup. This is especially true for plants and animals (microorganisms have such short turnovers that we don’t really impact them in this way); the plight of the blue swallow isn’t top of an industrialist’s list of priorities.

Despite these radical changes, some species have adapted to living in our towns and cities. This has piqued the interest of scientists and we’re now seeing the burgeoning field of urban ecology populated by urban ecologists. The amount of urban biodiversity is quite surprising and the adaptations of the flora and fauna comprising it equally so. Look at the previous post talking about birds lining their nests with material from discarded cigarette butts.

As civilization has developed we’ve become more aware of the value of nature, be it an intrinsic worth or a more practical value. So we can actively change our urban centres to accommodate more species if and when we choose. Sushinsky and colleagues asked how we should grow our cities in order to minimise their biodiversity impacts. Their conclusion was a more concentrated city plan would be better suited to avian diversity than a sprawling one. Certainly, it seems better for our cities to grow vertically rather than horizontally if we are to minimise humanity’s footprint. So, more New Yorks and fewer Los Angeles.

We can even provide supplementary food to animals. Fuller et al. showed that bird feeders can increase the abundance of birds and pointed out that up to a third of households in Australia, Europe and North America supply food for birds.

Then there are species that can prosper on our discards when it hasn’t been our intention to feed them in the first place. Badgers, foxes, raccoons, bears, the list goes on. All of them can make a living in an urban setting.

With more and more of us cramming ourselves into cities we should be aware that there are real benefits to interacting with nature. We feel psychologically better when there is more of the natural world around us.

To butcher Gordon Gecko, green is good.

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

wikimedia commons

31/12/2012

No animal is an island

No man is an island; the same could be said for the millions of life forms that populate our planet. Think of all the ways in which organisms interact with each other through predation, parasitism and the countless symbioses. Sometimes a pair of interacting partners can become inextricably linked such is their mutual dependence. Each one may provide the other with a resource it’s unable to obtain on its own.

A recent collaboration explored instances when these interactions lead to the loss of a trait and showed the fragility of this situation. One of the examples the authors use is an ant species that farms fungus. The fungus provides the ants with all the arginine (an amino acid) they need so they have lost the ability to synthesise it themselves. Thus anytime an ecological interaction involves some provision of a resource by one partner to another the evolutionary pressure is removed and the trait can be lost in the species receiving the goods. In other words we end up getting ‘compensated trait loss’ due to the ecological interaction. This can tighten a symbiosis from a facultative to an obligatory one.

But the fragility of compensated trait loss should be obvious now. In the ant example, were the fungus to go extinct the ant would disappear along with it. It’s like the ecological interaction is undermining all the good work done by natural selection in providing the ancestral ants with all the traits they need. The authors reckon that trait loss is “grossly underestimated” which puts many species in a precarious position in this age of mass extinction. Although there have been some instances where the trait was recovered, in flagrant disregard for Dollo’s law. Some of these law breakers include parasitic insects who regained their ability to synthesise lipids once the provision was lost.

A difficulty in studying these systems is how to detect when trait loss is taking place. A decreased expression of some gene in some members of a population would probably be reported as natural variation. But with ever improving molecular techniques we will be able to get a better estimate of the number of compensated trait loss interactions.

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

wikimedia commons

19/12/201203/01/2013

Smoking nests

We all know that cigarettes and smoking are bad for you. However, a recent Biology Letters paper which was featured on BBC Nature suggests that the discarded remains of cigarette butts may help to maintain the health of some urban birds.

Researchers from the National Autonomous University of Mexico found that smoked cigarette butts incorporated into house sparrow and house finch nests may act as parasite repellents. Nests which included high numbers of cigarette butts had fewer parasites. A further experiment involving heat traps to attract parasites indicated that the anti-parasitic properties of the cigarettes seemed to be related to their nicotine content which is only released after the cigarettes have been smoked. This doesn’t necessarily mean that the birds use cigarette butts as an adaptive anti-parasite strategy. Cellulose in the butts is an effective thermal insulator so any anti-parasite effects may be a fortuitous coincidence. The authors suggest that future behavioural choice tests could be used to determine whether birds can distinguish and preferentially include smoked cigarette butts in their constructions.

The paper is an interesting contribution to the growing fields of urban ecological and wildlife research. More than half of the world’s population now lives in urban areas so it is increasingly important to understand the ecological effects of this changing environment. Wildlife and urban areas are not always a happy mix – we have all seen the squished remains of a hedgehog’s attempt to cross a busy road. However, as this paper shows, sometimes urban animals can adopt novel behaviours which appear to have positive consequences.

However, I can’t see the paper being used to counteract anti-cigarette butt litter campaigns any time soon!

Author

Sive Finlay: sfinlay[at]tcd.ie

Photo credit

wikimedia commons

17/12/201217/12/2012

Hippo Critical

Hippopotami have been the talk of the Trinity College Zoology department’s tea room recently. Mainly because a number of staff are about to embark on a field trip to Kenya with some undergraduate students and hippos have featured highly on the list of possible animals which an encounter with might result in death or injury, I therefore decided to investigate, partly to allay fears but mainly to stir them.

In a recent study by Dunham et al. (2010) they investigated human-wildlife conflicts which have resulted in death or injury. The fact that Hippos are one of the most dangerous animals in Africa is common knowledge (in our tea room anyway), but the good news is that crocodiles are far more dangerous. Oh and lions, lions are really dangerous, but mostly crocodiles. In Mozambique crocodiles have killed more people than all other animals combined. More good news for our would-be travellers, only 55% of hippo attacks resulted in death, whereas the figure is close to 80% for crocodiles and alarmingly even higher for elephants. Though chillingly there have been reports of Hippos abandoning herbivory for a more carnivorous lifestyle.

Overall it is good news, hippos are not in fact that dangerous as long as you can manage to keep away from the water. So our intrepid explorers can relax in their campsite in their tents on the shores of lake Naivasha just remember hippos come onto land at night to feed, so perhaps pitch your tent away from the juicy grass.

Author

Keith McMahon: mcmahok[at]tcd.ie

Photo credit

Wikimedia commons

07/12/2012

The undiscovered island

Early ecological research relied on adventurous naturalists striking forth into unknown territory and expanding our knowledge of the natural world. This exploratory work is far from complete and many species new to science are still being identified. However, in order to study and investigate the remaining unexplored frontiers, knowing where they are is a fundamental necessity.

Finding our way around has never been so easy. GPS trackers are readily available; Google maps takes the stress out of navigating unfamiliar cities and Google Earth allows us to look down from above on some of the most remote regions of the world. The works of early cartographers with approximations of coastlines and vague “beyond here there are monsters” warnings can be relegated to historical archives. However, a recent discovery by the research vessel Southern Surveyor during its surveys of the seabed off Australia reminds us not to be so trusting of our highfalutin technology.

Sandy Island featured on weather maps and was depicted on Google Earth as lying halfway between Australia and New Caledonia. However, the 24 by 5 kilometre island was not marked on navigation charts. When the Southern Surveyor diverted its course to investigate the supposed island, they found only empty ocean with a depth of about 1.5km. Records of the phantom island seem to trace back to cartographic errors reported by the whaling ship, Velocity, in 1876. The island has now been removed from Google Maps.

From a biodiversity perspective, the non-existent island could have been home to a whole host of unusual and endemic species. The surrounding islands in this region of the South West Pacific are the remaining splinters of Australia’s separation from the ancient super-continent, Gondwana. They have high percentages of endemic species with New Caledonia recognised as one of the 25 global biodiversity hotspots. However, human colonisation of the Pacific islands caused significant biodiversity loss which continues today. If Sandy Island had existed, we can only speculate about the number of weird and wonderful creatures which, in the absence of human threats, could have called the island home.

Inaccurate maps from the 19^th Century aren’t that surprising but it is pretty incredible that in our technologically savvy age an island the size of Manhattan just doesn’t exist! One expedition member commented that the mistake “raises all kinds of conspiracy theories” especially when the CIA is one of the contributing sources to the world coastline database.

I guess this is just a reminder that Google is not omnipotent after all!

Author

Sive Finlay: sfinlay[at]tcd.ie

Photo credit

wikimedia commons

05/12/2012

Global Lakes Observatory Network Meeting

During unseasonably warm, dry and bright weather in mid-October,the Global Lakes Observatory Network (GLEON) held its annual meeting in Mulranny, Co. Mayo.

The meeting was organised by TCD alumni Elvira de Eyto, Eleanor Jennings and Valerie McCarthy, along with their GLEON, Marine Institute and Dundalk IT colleagues. GLEON represents a network of scientists working on lakes with high frequency physico-chemical observations obtained from buoys deployed with sensors. It is a grassroots network of limnologists, ecologists, information technology experts, and engineers who have a common goal of building a scalable, persistent network of lake ecological observatories.

Unlike more traditional conference formats, where attendees sit and listen to research presentations, GLEON members are grouped together to discuss their areas of interest, identify potential for collaborations and to make the decisions that will inform the future path of the GLEON network. Although the program was very full, the open, collaborative and discursive approach ensured the meeting was highly enjoyable.

The current membership of this global organisation currently stands at 351, attendance at the Mulranny meeting at more than 100 and as the photo shows, there was also a strong showing of TCD students and staff, past and present.

Author

Caroline Wynne: c.wynne[at]epa.ie

Photo credit

Caroline Wynne

03/12/2012

The selfish huddle

As it is December now and the frost is creeping in I thought I’d talk about one of the all time favourite winter animals: the penguin! These happy footed, tuxedoed up cartoon-esque waddlers are among the most charismatic and endearing of creatures. They are favourites in films, books, documentaries, toys and of course a must on Christmas cards. Tales of their romantic dances, lifelong partnerships and working together to get through the winter have long been a part of the ‘nicer side’ of wildlife television and research. But are these loveable, laughable poster birds of cooperation and cuteness really all that genuine? Recent research would suggest not…

It has long been observed that emperor penguins form mass huddles to help prevent heat loss while they incubate their eggs amid Arctic storms. Anybody who has watched March of the Penguins can’t help but feel for the poor mites as they shuffle about with ice crystals covering their faces! Morgan Freeman also gives a heart warming narrative of their struggles during this time and how they “take turns” to be at the centre of these huddles so nobody is left at the edges long enough to freeze entirely. Nice thought, but it seems not quite the reality. A paper published in Plos one last week looked at the mathematics of the famous penguin huddles. What they found was that the shape and movement of these huddles over time was most accurately (although not perfectly) described by individual penguins setting out to minimize their own heat loss, rather than generously taking turns. Penguins at the edges seek to move toward the centre while those in the centre have neither the space nor inclination to move anywhere so remain stationary. The result is a dynamic huddle that actually achieves pretty uniform heat loss from the huddle. So in this case being selfish can benefit the group.

This is not the first account of penguins acting in a less than Disney-like fashion: they have been observed stealing pebbles from neighbours’ nests and waiting to see whether other, more hungry, souls fare okay in orca/seal infested waters before jumping in themselves. There are stories too of them pushing their fellows off ice floats in to swelling seas to check for leopard seals but these are largely dispelled by researchers as misconceptions of the unfortunate results of the hustle and bustle of clumsy penguins perched on cliff edges!

I’m sorry to shatter any illusions of a wholly philanthropist snuggly-for-the-sake-of-it penguin but it is another nice example of how we humans often choose to perceive interactions in the animal world based on our own ideas of moral obligation: we like to see penguins cuddling in the cold to say “see what we can face when we work together?” Don’t worry though, I am sure that none of these findings will do much to shake the penguins off of their happy-go-lucky, cuddly pedestals and they will still be a key player in the Christmas festivities and focus points of many a blockbuster documentary to come. After all, who can resist that waddle!?

Author

Deirdre McClean: mccleadm[at]tcd.ie

Photo credit

www.funnycutepics.com

23/11/2012

A Waxwing winter you say?

The Bohemian Waxwing Bombycilla garrulus might not be a bird you are too familiar with, but this winter might change all that, for it seems we’re heading for a Waxwing winter. Don’t worry; Waxwings are not giant, flesh-eating birds. They are, in fact, a small and very beautiful passerine species that migrate to our lands to feast on fruiting bushes and trees.

The breeding range of the Bohemian Waxwing extends across most of northern Europe, Asia and western North America, and our nearest breeding populations are to be found in northern Sweden and Finland. These exotic-looking birds visit us each winter in small numbers but some years, known as irruption years, when the resources available at their breeding grounds are not enough to meet the demands of the population, there are huge migratory influxes into Ireland and Britain. One such cause of these irruption years is a failure of the berry crop and this is said to have happened across Scandinavia this year.

These birds typically arrive on the north and east coasts and make their way inland as they gorge on our rowan, hawthorn, rose hip and cotoneaster berries. Waxings tend to frequent urban areas as rowan and other trees line many of our gardens, streets and car parks (so next time you’re out shopping stop, listen and have a wee look around). I’ve heard from numerous people this year that the berry crop in Ireland has been very poor and this could spell bad news for the Waxwings. On top of this, we receive huge influxes of winter thrushes such as Redwing, Fieldfare and continental Blackbirds which are also berry fans, making for stiff competition.

So what then for the Waxwings? It seems likely they will keep pushing further west and south in search of more food – some have already shown up in Kerry, Cornwall and the Isles of Scilly! It will be exciting to see reports next year from monitoring programmes such as BirdTrack as to how far south, and in what numbers, the Waxwings were forced to migrate in search of food. You can take part in reporting them too. It will also be very interesting to see how their populations fare over the winter, especially if it’s a severe one. Let’s hope they fare well.

Author

Sean Kelly: kellys17[at]tcd.ie

Photo credit

wikimedia commons