ecology Archives - Page 7 of 10

22/04/201305/04/2019

School of Natural Sciences Postgraduate Symposium: Part 2/4

On the 15^th and 16^th April we had one of my favourite events at Trinity College Dublin: the annual School of Natural Sciences Postgraduate Symposium. Over the course of two days many of our PhD students presented their work to the School. We also had two amazing plenary talks from Dr Nick Isaac (CEH) and Professor Jennifer McElwain (UCD). For those of you who are interested in exactly what we work on here at EcoEvo@TCD, here are the abstracts from the PhD student presentations. Check out the TCD website for more details! Continue reading “School of Natural Sciences Postgraduate Symposium: Part 2/4”

19/04/201305/04/2019

School of Natural Sciences Postgraduate Symposium: Part 1/4

Postgraduate students from Trinity College Dublin's School of Natural Sciences — Postgraduate students from Trinity College Dublin’s School of Natural Sciences

15/04/2013

Disney Ecology

In light of the current stresses of exam season, I have been contemplating my parallel educational history. Of equal, if not superior, importance to any stage of my conventional academic life, I have had a Disney education. If I visit medieval castles or forts rich in feudal history I can’t help but mentally locate Rapunzel’s tower and contemplate the prince’s access route. My Greek mythological references are entirely based upon Disney’s Hercules and any mention of Rudyard Kipling is incomplete without at least one verse of the Bare Necessities. Zoological education is no exception. Early Disney films were rather loosely based on real zoological principles – I don’t remember Snow White using any Pavlovian theory to behaviourally condition her furry friends to help with the housework. Similarly, Mary Poppins serenaded an American robin from her London home because studio executives thought the sight of a European robin would be too confusing for their target audience. However, some recent Disney tomes are more grounded in realistic ecology. Disney was my first introduction to fundamental ecological and behavioural concepts as varied as breeding coalitions, mutualistic relationships and inter-specific communication.

Responsible for introducing Swahili phrases to a generation of Timon and Pumbaa fans, the Lion King is a Disney classic, both as a film and more recently as a highly popular stage musical (which is coming to Dublin soon – even if you don’t normally like musicals you must go to this show for the most incredible stagecraft you will ever see). The film marked one of the first times that animators made a specific effort to study their animal subjects to make their movements and behaviours as realistic as possible. Prior to the release of this film, my four-year old self didn’t know that male lions, often brothers, form coalitions to take over prides or that female lions take a cooperative, crèche approach to raising their offspring. Cooperative behaviour in lions continues to spark interest and research to understand why lions are unique among big cats in exhibiting these social tendencies. Of course, some creative licence remained in Disney’s depiction of their feline heroes – the voice of Darth Vader is sadly absent from the Serengeti and male lions don’t lead a troupe of goose-stepping hyenas in a song of revolution. Similarly, rather than a “king and queen”, there’s an equal dominance status within male members of a coalition and within adult females in a pride (unfortunately socially equal characters don’t lend themselves easily to a re-telling of Hamlet). Despite the sprinkle of Disney magic however, the basic ecological premise of Simba’s pride remains grounded in fact.

My ecological horizons were further expanded by Finding Nemo’s depiction of the mutualistic relationship between clownfish and the anemones they call home. It’s a deceptively simple relationship – the anemone’s sting provides the fish with a predator-free habitat while Nemo and his friends help keep the anemone free from parasites. However, many of the finer details underlying this interaction continue to spark research interest (and I’m obviously not the only one to have experienced a parallel Disney education). Nemo has provided evidence that mutualistic interactions tend towards a nested structure. More recently, the way clownfish move their fins has been identified as helping to increase anemones’ oxygen consumption at night – although, hampered by a malformed fin, I wonder whether Nemo’s personal anemone is gasping for breath a bit more than the other anemones? Furthermore, Finding Nemo did not neglect my geographical education – I now know that to get from the Great Barrier Reef to Sydney it’s just a short ride on the East Australia Current – and if I meet a turtle on the way, just call him “Dude”, Mr Dude is his father.

Thanks to Disney, Nemo’s pal Dory is another star of every aquarium. Forgetful but lovable, Dory was my first introduction to the realms of interspecific communication. While Dory speaks whale, it appears that some whales can learn to talk back. A captive beluga whale in San Diego seems to modify its call to mimic human speech. Neither of these examples are true interspecific communication; Dory’s valiant efforts to converse were unsuccessful and the Californian beluga’s “human” vocalisations appear to be relicts of an ability to mimic other whale species. In both cases, information is not passing between fish and whale or whale and human. Though who knows, perhaps Finding Nemo 3 will be a story of the quest to discover the Rosetta Stone for interpreting whale speech…

So through the talking animals, improbable alliances (why a meerkat and warthog??) and heart-warming moral tales, look out for the ecology in your next Disney film. Combining their subliminal ecological messages with the excellent work of the Disney conservation fund hopefully many more generations will experience a Disney ecological education.

Author

Sive Finlay: sfinlay[at]tcd.ie

Photo credit

wikimedia commons

27/03/201327/03/2013

Tyre Pressure

I’ve recently been spending a lot of time working with undergraduate students and marking their work and much of it has been on the subject of evolution and natural selection. This can be a difficult topic to clarify in the mind of younger students and it’s often difficult to recall specific examples which can be easily explained. Usually you have to come up with some hypothetical situation whereby some selection pressure drives a population towards evolutionary change. A newly published study in Current Biology by Brown and Brown however provides a beautiful (and more importantly brief) example of evolution and natural selection at work.

They have been studying populations of cliff swallows (Petrochelidon pyrrhonota) in Nebraska for almost thirty years, attempting to evaluate the costs and benefits of group living in these highly social birds. In an interview with John Dankosky lead author Charles brown explains how his habit of checking road killed birds for rings (or bands, as they are called in the US) led to an intriguing discovery. Firstly they noticed that over the years fewer and fewer birds were being killed on the roads (Figure 1), but also that these road killed birds tended to have longer wing lengths compared to individuals of the general population.

Figure 1. Change in wing length and number of road killed swallows (From Brown and Brown 2013).

So if you are a cliff swallow why does having a longer wing make you more likely to be run over by a car? Well it all comes down to the angle of escape. Birds with shorter more rounded wings are able to take off more vertically compared to individuals with longer more pointed wings, essentially shorter winged birds can get out of the way of oncoming traffic more quickly. It seems that this selection pressure from vehicles has been driving (I make no apology for the pun) the evolution of shorter wings in this population of cliff swallows.

Cliff swallows are migratory birds, travelling from South to North America annually and longer more pointed wings are generally seen as an advantage when it comes to long distance flight. Therefore it seems that the shorter winged individuals may pay an energetic cost compared to their longer winged conspecifics, but this cost may be outweighed by the benefit of being able to avoid traffic. Whatever the case may be I think this study provides a nice example of selection pressures steering morphological adaptations along the road to survival. Next time a student needs clarification on this I’ll remember, tyre pressure.

Author

Keith McMahon: mcmahok[at]tcd.ie

Photo credit

Tommie Kelly (www.tommiekelly.com)

25/03/201325/03/2013

Bees and biofuels….what’s the buzz?

As oil prices sore and the future of world energy is uncertain, there is rising demand for alternatives to fossil fuels. From solar energy to wind to algae fuel and biodigestion, the alternatives are numerous. One alternative that has received substantial media attention is the use of bioenergy which involves the production of energy from crops including maize, sugarcane, elephant grass and oilseed rape which are grown specifically for energy purposes.

However, the debate over bioenergy crops is often heated. Do they compete with food crops and therefore increase prices in an already stretched market? Do bioenergy crops result in the destruction of tropical rainforest to clear new areas for farmland? And are bioenergy crops even carbon neutral to begin with?

One debate that has been investigated by researchers in Trinity as part of the Simbiosys project is whether bioenergy crops can have impacts on biodiversity – the animals and plants that live on and in farmland. Not only are these animals and plants an important part of our heritage, but they are the pollinators of our food crops, the insects that control agricultural pests and the organisms that help provide us with clean water and air. With two-thirds of Irelands land area used for farming, any changes in farming practice are likely to have knock-on impacts on biodiversity.

A study recently published in the Journal of Applied Ecology investigated how growing bioenergy crops impacts the bees and other pollinating insects that pollinate wild flowers, apples, berries, oilseed rape, clover and many other crops here in Ireland (in fact pollinators are required for approximately 1/3 of all the food we eat). It was found that although different types of insect responded differently, there were no decreases of pollinators in bioenergy crop fields in comparison to their conventional farming alternative. And for some pollinator groups such as the small solitary bees, the introduction of small amounts of different crops into agricultural areas may actually be beneficial.

However, bioenergy crops did not provide the stable nesting conditions needed for pollinators; almost all bumblebees chose to nest in the field margins and hedgerows surrounding the fields. Field margins and hedgerows also provided habitat for large numbers of other insects. The study concluded that small amounts of bioenergy production on existing farmland may provide a diversity of habitats for pollinating insects, but that changes in levels of production in the future may have different effects. Hedgerows and field margins should also be maintained during bioenergy production as they are important nesting and forage sites for pollinating insects.

Although bioenergy crops in their current form seem like good news for bees, the future may be less certain. Growing these crops over larger areas rather than in individual fields, or the replacement of forests or meadows rather than existing arable (tilled) land, may have very different effects. With EU targets of 20% energy from renewable sources by 2020, and bioenergy incentives for farmers, we can expect further changes in this developing sector over the next few years.

Author

stanleyd[at]@tcd.ie

Photo credit

Dara Stanley

13/03/2013

Geese vs. Cyclists

From October onwards, when most of our resident wildlife is battening down the hatches to endure the impending bleak winter months, flocks of Brent Geese are very welcome visitors to Ireland. Their arduous journey to our shores is impressive for both its distance (approximately 3,000km from Arctic Canada) and the route taken: long-distance sea voyages punctuated by stop-overs in Greenland and Iceland before they reach Ireland. The necessity to escape harsh Arctic winters is very understandable. What’s not clear is why Brent geese undertake Atlantic crossings instead of following other geese species that journey south across the American continent. Whatever twist of evolutionary fate is responsible, there’s no doubt that we are lucky to receive annual visits from such intrepid voyagers.

I’m sure many Dublin residents would agree that sharing seaside walks with companiable small family groups of geese or witnessing one of the chattering fly-overs of a large flock undoubtedly brighten up an otherwise bleak winter’s day. However, a recent Irish Times article identified Brent Geese as the enemies of an unlikely foe; urban cyclists.

For more than 10 years, the S2S group has campaigned to create a continuous cycleway for 22km around Dublin Bay, running from Sandycove on the south side to Sutton on the north side which, if completed, would be Europe’s longest seafront promenade and urban cycle-path. The plan would be a great amenity for both recreational and commuter cyclists – you only have to travel along the coast road from Fairview to Howth to witness the popularity of the existing cycle path along the black banks. Just 8 km of the route remain to be completed, mostly on the south side and a single 4km stretch from Sandymount to Blackrock is particularly controversial.

The proposed route would cut through EU protected bird habitats and, in particular, affect an area of eel grass consumed by Brent Geese. The National Parks and Wildlife Service (NPWS) is also concerned about the impact of the cycle way on other bird species which reside in protected areas in Booterstown.

While I’m often wary of articles alluding to stereotypical views of “conservation hippies” thwarting sensible developments, in this case I have to agree with councillor Barry Ward that there must be a solution which “inconveniences rather than displaces” the geese. No development affecting protected habitats should be undertaken lightly. In particular, since the majority of Brent geese overwinter at just 10 sites, Birdwatch Ireland lists their conservation status as “medium concern”. However, with their current population seemingly in good health and the plethora of suitable habitat which Dublin Bay has to offer, it seems unlikely that an 8 metre wide seafront path would have a major impact on the goose population.

I’m well aware that if every development took the attitude of “there’s plenty of habitat elsewhere” then there would be no protected areas left. In addition, I must admit my vested interest in seeing the cyclepath completed – I’m a recreational (i.e. fair weather!) cyclist and live in Sutton so the availability of 22km of off-road cycling on my doorstep is a very attractive prospect. However, if you observe the behaviour of geese along the existing cycleway they seem to be remarkably unperturbed by adjacent human activity and continue to forage just below the boundary wall. Surely the same coexistent relationship between cyclists and geese could be forged south of the Liffey?

Despite including the S2S cycleway as part of their development plan councillor Barry Ward argues that management of the Dún Laoghaire Rathdown county council seems to be reluctant to develop the cycleway. Beyond the legitimate concern that the proposed cycleway would pass through a protected area, there seems to be no specific predictions or estimations that the development would have an adverse effect on the geese. Rather than an issue of cyclist vs. geese, perhaps this story is really a case of scape geese taking the blame for a council’s reluctance or inability to fund and implement a new development?

Author

Sive Finlay sfinlay[at]tcd.ie

Photo credit

wikimedia commons

08/03/2013

Fly Away Home

The University of Exeter team visited Ireland this week as part of their ongoing investigation into the biology of the Brent Goose. This species has a remarkable migration, spanning from Northern Canada to Western Europe. The team collects DNA samples, blood for stable isotope analysis and various morphometric and behavioural data. We joined them on Wednesday to help out.

Author

Adam Kane: kanead[at]tcd.ie

Photo credit

Adam Kane

06/03/201306/03/2013

Brown Bears and Shit Science

In my on-going attempt to improve myself I recently attended a lecture by Paul Eric Aspholm on brown bear tracking. This was a much more enjoyable and informative lecture than the last one attended and full of such interesting facts that I just had to share them!

Though the brown bear (Ursos arctos) is found throughout Eurasia and North America the talk focussed on those living in Scandinavia (Norway, Sweden, Finland) and Russia west of the Ural Mountains. In the first half of the 19^th century Scandinavia implemented a cull with the intention of wiping bears out. This cull was halted in the 1930s and since then populations have rebounded. Much of the work by Mr Aspholm involved tracking bears to determine population size and movements across the region.

The focus of the talk was shit. Lots and lots of shit. Spring shit, which is mostly grass. Summer shit, which is mostly meat and bones (growing bears need calcium!) and autumn shit, which is mostly berries. The bears are so dextrous that they can pick and eat individual berries and can get through tens of kilos of blueberries in a day! Female bears are quite careful about where they defecate but the males are much more casual in their toilet habits, to the extent that they sometimes accidently walk in a previous bear’s deposit!

The shit is gathered by helpful hunters (who sometimes collect human shit by accident!) and is sequenced to obtain genetic information about the depositor which can be used to track individual bears. Other tracking methods involve collecting hair in hair traps (a line of barbed wire set in a square with a delicious – to bears – smelling lure in the middle) and collecting footprints in snow. This last method was the most innovative (to me, at least). Bears walking over snow will leave skin cells in their footprints. All the scientists have to do is collect a few footprints (around 5-7), melt the snow, get the cells and then sequence the DNA to get a complete genetic profile.

These methods enable researchers to track the habits of individual bears over many years and sometimes several countries. They have been able to show that the bear populations have rebounded well since the end of the cull, with around 8 females reproducing each year in Norway. The hope is to get that to around 15 females a year, still significantly lower than the estimated pre-cull population but a healthy size considering the amount of habitat currently available to them. Most surprisingly of all, the populations show no evidence of genetic bottlenecking or reduced even genetic diversity despite little movement between populations.

As a public service we were given some tips in case we ever come across a brown bear. The traditional advice is to sing. This is, surprisingly, true as it is a sound that only humans can really make. If you scream, you sound like a frightened animal and a perfect chance for a snack. If you shout, you sound like an aggressive animal looking for a fight and the bear is likely to oblige. We were advised not look into their eyes, and most importantly of all – don’t turn your back on it. This is apparently an invitation to play and bears play rough!!

It was an absolutely fascinating talk and I learned so much. Many thanks to Mr Aspholm for such an interesting lecture.

Author

Sarah Hearne: hearnes[at]tcd.ie

Photo credit

wikimedia commons

04/03/2013

Could the ‘drone’ be a new technology to survey African wildlife?

Nazinga Game Ranch is a protected area in southern Burkina Faso, dominated by clear shrub and woody savannah and home to one of the most important elephant populations of the Western Africa.

Researchers from the University of Gembloux Agrobiotech in Belgium tested one of the first unmanned aerial surveys to study the wildlife of Nazinga. They achieved this study using ‘drone’ technology i.e. a small Unmanned Aircraft System (UAS) (pictured). This technology was shown to have the potential to be a valuable alternative to current walk and light aircraft survey techniques.

The Belgian researchers tested different aspects of this new technology on the wildlife and more particularly on elephants. Firstly they wanted to know if the animals reacted when the UAS passed over and found no animal flight or warning reactions were recorded when the plane passed over at a height of 100 meters. Secondly they flew the UAS at different heights (from 100 meters to 700 meters) and showed that only elephants are visible at these heights (while the medium and small sized mammals are not). The pictures taken at a height of 100 meters do however allow easy observation of the elephants.

In the light of this information one elephant survey has been completed in Nazinga Game Ranch so far. This UAS aerial survey has revealed several advantages in comparison to the traditional plane based surveying: (1) an easier flight implementation as a very short airfield is needed, (2) low safety risks as there is no pilot on board, (3) higher reliability in rough weather conditions, and (4) a lower global cost. However, to be able to cover hundred kilometres at a time it is important to improve the flight time of the small UAS as for the moment it is quite low.

Technological improvement of some aspects of the drone will make it more efficient and in the future could compete the light aircraft to monitor the wildlife in Africa.

Author

Florence Hecq: fhecq[at]tcd.ie

Photo Credit

Vermeulen C, Lejeune P, Lisein J, Sawadogo P, Bouché P (2013) Unmanned Aerial Survey of Elephants. PLoS ONE 8(2): e54700. doi:10.1371/journal.pone.0054700

01/03/201301/03/2013

Fantastic Mr Fox

At the launch of our recent college Green Week, Trinity College presented the final stages of its bid to secure the Green Flag Award. Part of the assessment comprised a summary of the plants and animals which, along with the rarefied species of Drama studientis and the Lesser Spotted Theoretical Physicist, contribute to campus biodiversity. Foxes were included in this list which surprised me since I had never come across one campus.

Happily though, last Friday evening one made an appearance just in time for the end of Green Week. Displaying the characteristic “boldness” of its habituation to city life and unperturbed by the passing cars, bikes, and rugby players, a large, healthy-looking fox trotted along the road beside me and into a small patch of scrubby bushes outside the Physics building. It must be a member of the den that resides in the Provost’s Garden – which received celebrity status in a recent Irish Times article. It’s intriguing to speculate whether the Trinity foxes cavort on the cricket pitch long after the last reveller has left the Pav on a Friday night? Similarly, I would love to know whether they are exclusive Trinity residents or do they dodge the shoppers on Grafton Street to visit their cousins in St. Stephen’s Green? Perhaps they also visit Merrion Square – pausing along the way to pay homage to some long lost relatives entombed inside display cases within the Natural History Museum.

Urban foxes have received some bad press recently after the rather gruesome story of the fox which bit off a baby’s finger in south east London. The RSPCA was quick to stress that, while truly horrific, this incident was extremely unusual. Despite their reputation for pilfering unguarded bins, foxes are usually quite shy and wary of coming too close to humans. However, in the wake of the London attack, Mayor Boris Johnson, labelled urban foxes as a “pest and a menace” and there were many calls for a large-scale culling operation to be instigated.

These emotive responses to an isolated incident should not be allowed to dictate future policy for dealing with urban foxes. In his recent New Scientist article, Stephen Harris points out that we are more likely to be attacked by pet dogs rather than foxes and culling programs simply don’t work since new animals just move in to fill vacated areas. In his view, it’s human rather than fox behaviours which give cause for concern. He argues that natural history programs which show cavalier presenters coming in to close contact with wild animals encourage people to seek unnatural and sometimes dangerous proximity with urban wildlife. For example, leaving food out in the garden to attract foxes can lead to some great sightings of these beautiful mammals but placing that food close to a house or near open windows or doors is just asking for trouble. Moreover, feeding foxes is a divisive issue in itself – is it akin to leaving food out for birds or does it equate to just attracting unwanted pests into our gardens? Personally, I have no issue with leaving out scraps but buying cat or dog food just for foxes seems excessive, especially when our untidy cities are veritable all you can eat buffets for these city slickers.

Whether you regard them as pest or surrogate pet, foe or friend, foxes are an inescapable feature of urban landscapes. With Trinity’s campus as their playground, who knows what the one I saw gets up to after dark?

Author

Sive Finlay: sfinlay[at]tcd.ie

Photo credit

wikimedia commons