Tag: conservation

Posted on

Bird Feeders

AWBVDSC_2691.jpeg-p194p512d2km1im218hp1hk2sjt-0It’s coming up to winter so people will be conscious that our garden birds need a helping hand to get through the cold months. Bird feeders will be stocked, bread served up and water dished out. In the UK alone, almost half of households provide supplementary food for birds throughout the year. And although songbirds are usually the species that come to mind when we think of provisioning food the same principle can apply to more exotic birds, notably vultures. Indeed conservationists have supplied extra food to these scavengers for decades. Instead of bread or berries, a carcass is left out for the vultures to feed on. A recent paper of ours advocates this technique for a population of African White-backed Vultures in Swaziland.

This country is home to the densest breeding population of this species so we should do our best to conserve them given the huge declines suffered by vultures throughout the Old World. In the paper we showed times when there isn’t enough food in Swaziland to feed the whole population which means the birds are forced to forage farther afield, most likely in South Africa. On the face of it this doesn’t seem problematic because South Africa has huge populations of herbivores which could supply carcasses to vultures. But the birds must fly over unprotected areas as well. This increases their chances that they’ll encounter a poisoned carcass, perhaps set out by a farmer to kill the terrestrial carnivores harassing his livestock.

It’s well known that vultures are particularly sensitive to poisons, especially NSAIDs. Their group foraging behaviour makes them even more susceptible too, the discovery of a carcass by one individual will bring in the rest of the soaring birds in visual range. The hope with creating vulture restaurants is the birds will focus on foraging for carrion in Swaziland, minimising the risk of poisoning.

Yet there are well known problems with supplying supplementary food for animals in general. They may act as an ecological trap for instance, drawing the birds into an area only for the fickle humans to stop the supply of food. Carrion is an unpredictable resource so vultures forage in a characteristic way to improve their chance of encountering it. If food is supplied in a predicable way there is a fear we may disrupt these behaviours. Another recently realised danger in providing supplementary food is that it can attract unwanted guests. Sites tailor made for vultures in South Africa were shown to draw in jackals and hyenas.

Given these issues practitioners need to think carefully about how they provide food. Perhaps the best approach is a series of sites supplying food at random which would best represent the distribution of naturally occurring carrion.

Author: Adam Kane, @P1zPalu, kanead[at]tcd.ie

Photo credit: Munir Virani

Posted on

A tern-up for the books

Little Tern taking off from nest © Andrew Power and Peter Cutler
Little Tern taking off from nest © Andrew Power and Peter Cutler

The last two years have seen successive record breeding seasons for Little Terns (Sternula albifrons) on the Irish east coast, with over 350 pairs breeding in 2013 and over 400 pairs in 2014. These record years are the result of 30 years of dedicated efforts to rescue Little Terns as an Irish breeding species, after population collapses in the 1980s and 1990s. As part of the BirdWatch Ireland team involved in these two exceptional years, we reflect on the conservation success story which has led to this remarkable tern-around in fortunes. Continue reading “A tern-up for the books”

Posted on

The Wakatobi Flowerpecker: the reclassification of a bird species and why it matters

Wakatobi Flowerpecker - Male

I posted previously about my PhD research studying bird populations from the tropical and biodiversity-rich region of Sulawesi, Indonesia. I am happy to announce that the first paper as part of this research has just been published in the open access journal PLOS ONE. To read the full paper for free, click here. This work is a collaborative effort from staff in the Department of Zoology in Trinity College Dublin and Haluoleo University in Sulawesi. Here, I’d like to discuss the wider importance of the findings of this study.

My current research focuses on bird populations from peninsular South-east Sulawesi and the nearby Wakatobi Islands. The main focus of this paper was to reassess the taxonomic status of a population of birds from the Wakatobi Islands (i.e. whether these birds represent a species or subspecies). The birds in question belong to the flowerpecker family (Dicaeidae); a group of small and colourful, arboreal passerines found from Southeast Asia to Australia. The Wakatobi birds were originally described as a separate species (Dicaeum kuehni) from those on mainland Sulawesi by the renowned avian taxonomist Ernst J. Hartert. However, for reasons that remain unclear in the literature, the Wakatobi birds were later reclassified as a subspecies of the Grey-sided Flowerpecker (Dicaeum celebicum) from mainland Sulawesi. Therefore we decided the Wakatobi populations were deserving of reassessment. From comparisons of plumage and morphology (that is, the measurement of various features such as a bird’s wing and bill), as well as estimates of genetic divergence and phylogenetic relationships between Wakatobi and Sulawesi populations, our results suggest the Wakatobi birds deserve to be recognised as a distinct species. We have therefore recommended the Wakatobi populations be reclassified as Dicaeum kuehni, a species found only on the Wakatobi archipelago and put forward the common name ‘Wakatobi Flowerpecker’.  For more detailed methods and results check out the paper.

“So what?”, you might say. Well, despite centuries of work from naturalists aiming to estimate the number of different species that exist or have existed on Earth (be they animal, plant, fungus, bacteria, etc) and further understand their evolutionary relationships, we still have a lot to learn! Therefore, this research adds another tiny piece to this enormous and incomplete jigsaw. Through a greater understanding of life on Earth we can attempt to answer some of the great philosophical questions, such as ‘Where and how did life start?’; ‘How and why do new species appear?’;  ‘Why has life evolved to become as it is today?’; and ‘How have we, as humans, come to be?’. Anyway, let’s be honest, who doesn’t enjoy learning of a recently discovered species or simply one they haven’t heard of before (be they as cute as the recently discovered olinguito or as frighteningly ugly as the goblin shark)? But the endeavour to discover species and classify and quantify the diversity on life on Earth brings us much more than entertainment and endless fascination, it also has very practical applications. Data on the distribution and conservation status of species are one of the major sources of information used to inform conservation policy. Therefore, as we are in the midst of an extinction crisis, it is vital that these data are accurate.

In order to maximise our understanding biodiversity, particularly in the remote and poorly known Sulawesi region of Indonesia, we require multi-disciplinary research. For example, take a look at Figure 1 below. On the left are a male (above) and a female (below) Grey-sided Flowerpecker from mainland Sulawesi. On the right are a male (above) and a female (below) Wakatobi Flowerpecker. They look very similar, right? This is true. However there are subtle but consistent differences in plumage between the species (again, see the paper for more info on this). Without the collection of detailed morphological data and the generation of genetic sequences, we may have incorrectly concluded that these make up just one species, when in fact they are morphologically distinct, reproductively isolated and genetically very different. This demonstrates the need for modern research, not just in Sulawesi, but globally, to employ integrative research, combining traditional comparisons of colour, size and shape with modern genetic and phylogenetic analyses.

Figure 1. Plumage comparisons-p18pjcggcs1dgo1ulm1sor9s214bc
Figure 1. A comparison of plumage characteristics between male (top row) and female (bottom row) Grey-sided Flowerpeckers (left) and Wakatobi Flowerpeckers (right).

Despite the knowledge that the Sulawesi region is home to a large number of remarkable birds that are found nowhere else in the world, it has remained relatively poorly studied. Furthermore, there has been a lack of integrative ornithological research in the area and very little genetic sampling. Therefore, it is likely that avian species richness for the Sulawesi region is underestimated and that numerous bird species are awaiting description. On top of this, Sulawesi’s biodiversity is facing major threats from a rapidly expanding human population and mass habitat destruction, among other things. Unless we can encourage more multi-disciplinary research within the region, we will likely fail to recognise evolutionarily distinct lineages and run the risk of losing them forever.

Our current findings inspire many further questions. For example, why have the flowerpeckers on the Wakatobi islands become so different to their close relatives on mainland Sulawesi? In other words, what are the evolutionary pressures that have driven the divergence of the Wakatobi Flowerpeckers? By investigating these questions, we hope to learn more about the evolutionary processes of speciation and adaptation to living on islands. As the Wakatobi Flowerpecker is found only on the Wakatobi Islands, the protection status afforded to the islands may require reassessment. Furthermore, considering one unique bird species has evolved on the Wakatobi, could there be more? Watch this space.

Author and Images:  Seán Kelly, kellys17[at]tcd.ie, @seankelly999

Posted on

Kakapo Conservation

In centuries past, if you were to go into the hills of New Zealand on a summer’s night you may have heard a strange noise; a honking boom that resonated all around you. After 20 or 30 cycles of this boom you’d hear a high-pitched rasping ‘ching’ sound. This boom and rasp would come from all around you and would be heard all night, night after night for at least two months. This is the sound of kakapo males trying to attract a mate.

Kakapo 1

Kakapos, (Strigops habroptilus) are nocturnal, flightless parrots. They are found exclusively in New Zealand and while they were once common across all three main islands of New Zealand, they are now restricted a few small offshore islands. They are unique birds in a number of ways. They are the only flightless parrot and, probably as a result of this, are also the world’s heaviest parrot. They are also the only parrot to chose mates using the lek mating system.

Lek mating involves males displaying for the females and the female picking “the best” male. It’s a winner-take-all scenario as different females usually chose the same male. If you’re the chosen male then it’s a successful breeding season but if you’re not then you go home empty-handed. Males in lek systems typically take no part in the rearing of offspring and kakapo are no different.

Kakapo use an ‘exploded’ lek system, where males are generally out of sight of each other (the more traditional system has all males within eyeshot). During the summer months they go to hilltops and ridges and create a bowl in the earth in which they sit. These bowls are thought to help amplify their booms. They may have several bowls which are linked by tracks created by removing vegetation [1]. They then inflate a sac in their thorax and create the booms and chings. The booms are to attract a female and the ‘chings’ help her to find him as the booms can travel up to 5km while the ‘chings’ are more locatable due to their high frequency. Once a female has been attracted to a particular male and enters his view he performs a dance for her after which they mate

The female lays between one and four eggs in a makeshift burrow, either in cavities such as in those in trees or under vegetation. The eggs hatch within a month and she then has to look after the chicks for up to six months, though they leave the nest after about three months.

Kakapo 2

Kakapo only reach maturity after the age of about 5 and females only start breeding around the age of 10 [2]. Females reproduce every few years after a masting event. Masts are where plants, in this case the rimu tree, produce large amounts of fruit simultaneously, overwhelming the local wildlife with food. Even with the increased food not every female is able to get fit enough to exert the energetic costs associated with reproduction  and so not all females will breed in a given year [3].

As I explained in a previous blogpost, New Zealand avifauna has been threatened by the introduction of predators. Given their slow reproductive rate and terrestrial lifestyle they are particularly vulnerable to predation and have been pushed to the edge of extinction. By the 1970s less than 20 were known to exist and all were males. It seemed that the kakapo were doomed. But in 1977 a female was found on Stewart Island and from that one female a miracle has occurred and the population currently stands at 130 birds.

This success has been hard won. Part of the problem is that so little is known about the birds that trying to get them to breed successfully has been challenging. Added to that the long life-span (it’s not known how long the birds live but it appears to be decades) and the slow reproductive rate means that conservation efforts are going to take decades if not centuries before it is known whether or not they have been successful.

One stumbling block that was hit was an unintended consequence of trying to increase the number of breeding females. Females only breed when they reach a minimum weight. In order to increase the number of breeding females in a given year they were given additional, or supplementary, food. The unintended consequence was that this resulted in more males than females being reared.

Kakapo 3

The Trivers-Willard hypothesis predicts that females will produce more males when they are in good condition and more females when they are in poor condition. The idea is based on the costs and benefits of each offspring in terms of her ability to transmit her genes to future generations. In polygynous systems a female will be able to mate with a male regardless of her fitness: the males don’t care whether the females are only just fit enough to reproduce or are at peak condition. But in the same system only the fittest males can beat their rivals and gain access to females. The fitness of a female will affect the fitness of her offspring so if she’s not particularly fit it is in her interests to produce females whose future fitness will not significantly affect their reproductive potential. If she’s at peak fitness, however, it’s in her interests to produce males who are more likely to be the dominant male and be able to beat rivals to females.

You may be able to see the unintended consequences already. The supplementary food pushed all the females into top condition and they all produced males. Experimental supplementary feeding at different levels was used to confirm the hypothesis and found to be true [3]. As a result, the supplementary feeding program was adjusted so that females at fed to a level of fitness where they could successfully reproduce but are not so fit that they produce only males. It has been so successful that from the highly skewed sex ratio at the start of the programme it is now approaching parity with 70 males and 60 females.

The conservation program still has a long way to go before kakapo can be considered to be saved. It may be that disease (highly possible given the low genetic diversity) or a series of unfortunate events reduces the population to a level from which it cannot recover. In some sense the birds are living on borrowed time, but despite the uncertainty of success, the effort is well worth it. These birds are unique in the world and are worthy of our care and conservation. Long may their ‘borrowed time’ continue.

Kakapo 4
Don Merton, saviour of the kakapo, with Richard Henry, one of the more famous kakapo

 

Author: Sarah Hearne, hearnes[at]tcd.ie, @SarahVHearne

Image Sources: Wikicommons

References:

1) Merton, D. V et al. (1984)

2) Eason, D. K. et al. (2006)

3) Clout, M. N. et al. (2002)

 

Posted on

Kapapo, Kereru and Kaka, Oh My!

Before I moved to New Zealand birds were, well, birds. They were nice to see but I didn’t pay them much attention. But New Zealand is a bird paradise and as a biology student (I studied for my undergraduate degree at the University of Auckland) birds were the go-to exemplar of many biological concepts. With understanding often comes interest and I found myself increasingly interested in our avian friends, an interest which has stayed with me to this day. Continue reading “Kapapo, Kereru and Kaka, Oh My!”

Posted on

Rewilding

wolf

Rewilding is the mass restoration of ecosystems by reintroducing (often long) lost animal and plant species which are then left to develop without human interference. It’s a topic explored by journalist George Monbiot in his latest book, Feral [1]. Monbiot captures the controversy surrounding rewilding with typical understatement, “Reintroducing elephants to Europe would first require a certain amount of public persuasion.” And “The clamour for the lion’s reintroduction to Britain, has, so far, been muted.” So why should we do it? He argues, and I agree, that people would value a biologically rich world over the desolate sheep-scapes that are common to the UK and Ireland. We live in a shadow world where we can see evidence of species that once surrounded us. One of the more striking examples of this shadow world are the putative elephant-resistant adaptations seen in Temperate trees. So, over and above the ecosystem services that would be realised and the potential financial gains resulting from such an endeavour, the primary motivation here is to nurture the existence value we draw from biodiversity.

The wolf reintroduction to Yellowstone is a great example of a successful reintroduction whose effect was felt throughout the trophic web. The wolves created zones of fear, areas where their prey no longer dared to venture which allowed vegetation to reestablish. This, in turn, gave habitat for animals like beavers to occupy. This in turn had a massive knock-on effect on the entire ecosystem and the other habitats of the park, all of which illustrates the profound influence predatory megafauna can have and the disastrous and unrectifiable trophic cascade which can occur where they are excluded.

Naturally, there are some serious obstacles to advancing this goal. It’s not a simple matter of dumping a pride of lions into the woods and hoping for the best. There will have to be some priming of the area if we want the animals to flourish. The Irish countryside isn’t as well suited to wolf packs as Yellowstone. This is especially the case if Pleistocene rewilding is taken seriously. Monbiot explains, “People who call themselves Pleistocene rewilders seek to recapitulate the prehuman fauna of the Americas.” This could be achieved through DeExtinction of long-lost species or by reintroducing proxies which would serve the function of the missing animals or plants. In the US where there are extensive wildlife areas that we Europeans could only dream about, reintroducing long disappeared animals or proxies doesn’t seem quite so ridiculous. For us, with so little unmodified habitat it almost seems like a non-argument when we don’t even have mundane megafauna or any land on which to put them. To take one example, the African species of cheetah could fill in for the American species (Miracinonyx), preying on the fleet-footed pronghorn, whose speed is another instance of an adaptation to a long-lost predator. But the issue here is the time that has elapsed since these species went extinct. Perhaps the ecosystem has changed too much for the species, proxy or not, to settle back in. Modern day North America is a very different place to the one of 12,000 years ago.

There is ample opportunity and, more importantly, land, to proceed with rewilding plans outside of traditional protected areas. Agricultural property is being abandoned all over Europe and North America as people move to cities. Rather than keep it fallow, why not restore the landscape to something of value?

This would represent an excellent opportunity for scientists and policy makers to engage with the public and highlight the benefits of rewilding or at least get it into the public consciousness. Of course there will be detractors, but the arguments for could be framed in such a way as to convince most reasonable people that wolves won’t be stalking their estates. I think rewilding is an exciting way to develop conservation; it is dynamic which is in contrast to the passive, ‘protect what we’ve got’ ethos, common to conservancy. It also brings some much needed positivity, opposed to the negative, guilt-laden, reactionary aspect of much of nature conservation.

Authors:  Adam Kane: kanead[at]tcd.ie, @P1zPalu

John Kirwan, @JohnDKirwan

References

1. Monbiot, G., Feral: searching for enchantment on the frontiers of rewilding. Allen Lane, London, 2013.

Image Source: Wikicommons

Posted on

Killing in the Name of Science – Dying for Conservation

Conservation. Noun. From the Latin verb conservare, to protect from harm or destruction.

Dallas safari club auctions off permit to hunt rare rhino.

Giraffe unsuitable for breeding killed at Copenhagen zoo .

Six Lions at Longleat safari park destroyed due to excessive population increases.

What on earth is going on?

These stories have gone around the world and caused almost unanimous outrage. This is not surprising. The disparity between the ideals of conservation and the sometimes tricky real-world dilemmas that occur can cause consternation and indignation to many. Given my previous posts you won’t be surprised to learn that it might be a bit more complicated that the headlines have led us to believe. So let’s delve a bit deeper and see whether these animals were justifiably killed or whether there’s something else going on. As always, I’m going to try and leave the ethical considerations to one side as much as possible and focus on analysing the scientific justifications given. So, on with the show . . .

The Rhino

rhino

In early January a permit to shoot an elderly rhino was auctioned off to raise money for rhino conservation. There are arguments on both sides as to whether this was a good idea. The rhino was, according to reports, an old, non-breeding male rhino who had the potential to injure or even kill younger males. Removing him as a threat seems to be a good idea. Culling occurs in many managed populations and is used to maintain healthy, sustainable populations. Removing this animal from the population is, based on our understanding of male rhino dynamics, the best course of action scientifically.

Whether the auction was the best way of achieving this is outside my remit. Culls can, and do, occur with less publicity and spectacle. Given the outrage expressed, it would be interesting to know how many of the people complaining had ever donated to rhino conservation organisations. If the organisations were not so desperate for money would they have ever considered such a headline-grabbing action?

The Giraffe

giraffe

Copenhagen zoo killed a giraffe that was considered useless for breeding . They then publicly dissected it and fed it to their lions. This story is the most interesting as it has two separate components: the killing and the treatment of the animals after death. Here I am extremely split. Captive giraffes are, to some extent, victims of their own success. Breeding programmes across Europe have been very successful and zoos are pretty much at ‘carrying capacity’ with few able to take excess giraffes and genetic inbreeding is becoming a problem. One of the zoos that offered to take the giraffe already has his older brother which was the argument used against the transfer.

The obvious solution would be to prevent the giraffes from breeding in the first place but this isn’t always easy in giraffes. From the BBC article,

“Contraception and castration have been raised as possibilities, but both would require sedation. This is a relatively high-risk procedure in the case of giraffes, as they are liable to break their necks when they fall while sedated.”

There are contraceptives available now that can be used with little risk so the number of ‘excess’ giraffes should reduce in the future. However, Copenhagen Zoo has a policy of allowing their animals to breed naturally, even though this is clearly causing a surfeit of animals.

As to the treatment of the body, I’m in no doubt they did the right thing. One of my favourite TV programmes in recent years was Inside Nature’s Giants where large animals were dissected and their anatomy and evolution was described and shown in all it’s ‘gory’ detail. I am all for increasing the public understanding of how animals work and the crowds that gathered to watch are proof that this interest exists. It is important to demystify biology and this is a great way of doing so. As for feeding the giraffe to the lions, well, what else were they going to do with it? Bury it? Burn it? Either way a waste of meat.

While I’d intended to ignore everything but the science, it’s proving incredibly hard! So my editorial for this story is that I’m not sure that killing the giraffe was the best idea. There were zoos that were offering to take the giraffe and, while it may not be the ideal option in terms of the breeding program, it is up to the zoo taking the giraffe to determine this. If they think the benefits of having another giraffe (and the public goodwill they will receive for offering sanctuary) outweigh the costs then I think this is their decision, not Copenhagen Zoo’s. The zoo needs to consider contraception as another instance like this will not go down well with the public and zoos are reliant on public support for their continued existence. I’ve seen several people say they will never visit the zoo and if they hold true to their word and their example is followed, Copenhagen Zoo is looking at tough times ahead.

Their decision to use the killing as an educational exercise was the best thing they could do, though I do find it strange that a lot of the outrage seems to be directed at the public nature of everything rather than the killing in the first place. The outrage is precisely why this should be done in public, though I do think the attitude of the zoo has been a bit too confrontational and almost designed to cause outrage.

Lions

lion

Finally, the lions. Lions have been synonymous with Longleat for decades so to hear that they have killed six is almost unbelievable. As with all these stories there is public outrage, with people unable to understand how an organisation that has looked after lions for over 50 years can end up with killing an entire litter. As with all these stories, digging a little deeper reveals a more complex story. A statement from Longleat was given to HuffPo where they explained why they felt the litter needed to be destroyed. The cubs had genetic problems due to inbreeding which was could result in brain tumours and was already causing behavioural problems. From their statement,

“. . . all [cubs] individually exhibited adverse neurological signs such as ataxia, incoordination and odd aggressive behaviour that were not considered normal . .  One of the cubs had to be put down because he was attacked by his brother and by Louisa [his mother]. The further lions referred to were put down due to associated and severe health risks.”

From this statement it seems that euthanasia was an inevitable and unfortunate consequence of inbreeding in their mother (breeding that did not occur at Longleat). It highlights why breeding programs must be carefully monitored and controlled and why animals like the giraffe should not enter the breeding population.

Conclusions

This has turned into more of an opinion piece than I’d intended which was, I suppose, inevitable considering the contentious nature of the stories. I hope I have shown that there are more to the stories than the headlines and they are more justifiable than they may first appear.

Zoos play an important role in conservation and education. They have to make difficult, unpopular decisions at times and when they do it is vital that they explain clearly their scientific rationale. The public are quick to react without getting all the facts and if you don’t explain your case carefully you risk a backlash that can have significant negative consequences. The science may be sound but the ‘politics’ surrounding the stories is more controversial and must treated with as much care as the scientific decisions that instigated them.

Author: Sarah Hearne, hearnes[at]tcd.ie, @SarahVHearne

Image credits: Wikimedia commons

Posted on

Seminar Series: Nathalie Pettorelli, Institute of Zoology, London

space monitoring

Part of our series of posts by final-year undergraduate students for their Research Comprehension module. Students write blogs inspired by guest lecturers in our Evolutionary Biology and Ecology seminar series in the School of Natural Sciences.

This week, views from Sharon Matthews and Sinead Barrett on Nathalie Pettorelli’s seminar, “Monitoring biodiversity from space: a wealth of opportunities”.

Space, the final frontier for ecology?

Okay, you got me.  I am a trekkie who is fanatical about anything space related. So when I saw that this week’s seminar was to do with conservation biology from space, I was hooked!  Dr. Nathalie Pettorelli from the Institute of Zoology, London spoke with passion and enthusiasm about a new wave of ecology; monitoring species and ecosystems from space.

We were treated to information about remote sensing and how data from satellites can be used to help ecologists in the tasks of assessing population size and habitat condition. Earth observation (EO) data is free and is ripe for the picking.  Satellites are able to “boldy go where no one has gone before” or very few people have (sorry, I will stop with the star trek quotes now!).  They can get information on places that are often inaccessible and inhospitable for the lowly researcher like Antarctica and the Sahara desert.

One of the major tasks ecologists face is estimating the size of a population.  Dr. Pettorelli talked about an ingenious research project that used information from satellites to gain an estimate of the population of emperor penguins (Aptenodytes fosteri) in Antarctica.  Emperor penguin populations may be affected by climate change in the next few decades due to changes in sea-ice distribution and therefore it is important to get an estimate of the extant population.

Frettwell et al. (2012) examined quick-looks from three different very high-resolution satellites.  These have a resolution of ~ 10m and are able to show great detail.  The researchers looked for staining on images and classified it as snow, penguin, shadow or guano.  When areas with penguins were identified, they analysed the penguin pixel area through regression equations.  The statistics gathered from this were used to convert the area of penguins to population numbers.

In this study, the identification of a penguin from a pixel area was done by human interpretation and this led to some error especially in areas of high guano staining.  This could be resolved with future development of higher resolution satellites.  However, there were other issues that arose from using this technology.  Researchers identifying penguins from pixels made an assumption that a pixel constituted one individual when it may in fact have been an individual with a chick close to it.  This can affect the estimated population size.  The kind of error association with using satellites makes me think that this satellite approach should be backed up with other methods such as field study where possible.

Remote sensing can allow research to be undertaken over a broad spatial and temporal scale.  One of Dr. Pettorelli’s projects involved using EO data to assess a game reserve in central Chad for its ability to sustain a reintroduction of the Scimitar-horned Oryx (Oryx dammah).  A vegetation index (an indication of ‘greeness’) and annual mean precipitation, were assessed over a 27-year period for this game reserve. The results showed that precipitation was a main driver of vegetation dynamics and there was an intense greening in the south of the region.  Dr. Pettorelli also found that there was a contraction of the transition zone from north to south. This was an area that was identified as most suitable for the oryx.  This study showed how remote sensing can help inform ecologists about variation in a region over time.  It can greatly enhance the success of reintroducing a species into a suitable area.

There is no doubt in my mind that data from remote sensing can help ecologists in their work but I don’t think it should be used in isolation. Ecosystems involve a complex mix of interactions of many variables. Therefore, this approach could be used alongside other tried and tested (down to earth) methods of studying ecosystems and biodiversity.

Author: Sharon Matthews

——————————————————-

Evidence of Global Change is Sky High

As we all know, climate change is affecting the world in which we live. One aim of scientists is to find out the extent of this change. At a seminar given recently in Trinity College Dublin, Dr. Nathalie Pettorelli from the Zoological Society of London informed us about a new method of doing this. With benefits including the cost, its sustainability, reproductivity and standardised information, satellite usage as a way to monitor biodiversity seems like an excellent option.

Dr. Pettorelli mentioned the vast array of options of satellites available for monitoring depending on what you want to find out in the study. For example, very high resolution imagery has been used in order to count penguins in colonies, Landsat has been used to study the gorilla habitat in Virunga and LiDAR satellites which give a 3-D image have been used in the Bavarian forest. But what interested me most was when Dr. Pettorelli mentioned the ability to monitor vegetation indices and how this technique was used in the reintroduction process of the Scimitar-horned Oryx in Ouadi Rimé-Ouadi Achim Game Reserve in central Chad.

The Scimitar-horned Oryx was last found in the wild in the 1970’s. However it has been kept in captivity and there were plans of reintroducing it back into this area in central Chad. In order to do so, a habitat assessment was undertaken to establish whether the area would still be suitable for the species to live in. The primary productivity over the past number of years was viewed using remote sensing (satellite) techniques. It was seen that the vegetation in the north had significantly dried while the area to the south showed intense greening. Because the Oryx lives preferably in sub desert regions, suitable habitat here was declining and it was not advised to reintroduce this animal to the area.

To me, this shows just how important this method of monitoring is. Due to the increased changes that come about as a result of climate change, species are no longer suited to their natural habitat. Although it wasn’t mentioned in detail in the seminar, it struck me that one use of this satellite method of monitoring would be to use it in assisted migration. This is a method of conservation that involves humans undertaking a translocation of an animal or plant species. This is used when a species can no longer survive in their habitat and so must be moved to a more suitable area. This method of conservation is debatable as there are many associated risks involved including the impact on original species in the new habitat. However, with scientists doing research on this to study possible effects, it may save a species from dying out. Suitable habitat needs to be found for assisted migration to work. The methods that Dr. Pettorelli uses in her habitat assessment in central Chad could be the ideal way to find these habitats needed. This highlights the need for this new method of data collection. Because it is done at such a big scale, it seems like an excellent way of finding large habitats suitable for a new species, whether it’s a tree or a large carnivore.

Changes are occurring globally as a result of anthropogenic actions, and species worldwide are dying out as a result of this. It is clear from the numerous examples mentioned at the seminar that there are many uses of satellite imagery in monitoring biodiversity worldwide. After hearing Dr. Pettorelli talk about this subject, I left realising just how important technology such as satellites are in a time when global change is sky high.

Author: Sinead Barrett

 

Posted on

Cape Vulture Conservation

Cape-vulture

Conservationists try their best to stop endangered species sliding to extinction and keep the habitats of these life forms intact. Captive breeding programs, national parks, management of invasives etc. are all common measures in conservancy. But how do we know that these methods work? Perhaps an invasive species is actually serving as a food source for the conservation target, and, by killing off the former, we imperil the latter further still. Fortunately, we can avoid such disasters through experimentation and modeling, in other words, with some good science.

Consider the case of the Cape Vulture (Gyps coprotheres) in Southern Africa. This large scavenger patrols its habitat, often a huge range, foraging for carrion. It’s suffering a decline in numbers for a variety of reasons. Carcasses are often poisoned to kill predators that take farmer’s livestock with the vulture an innocent victim. Their social nature means tens of the birds can be killed by a single toxic carcass. More direct persecution comes in the form of poachers who have taken to poisoning the carcasses of their quarry. The rationale is to wipe out vultures who will identify the location of future crimes. Then there are accidental deaths that arise from bird collisions with electricity pylons and wind turbines. And it will take some time to convince otherwise those who value vulture brains for their clairvoyant properties.

Fortunately, some vultures survive these incidents and that’s where rehabilitation centres come in. People at these facilities nurse the birds back to health and release them into the wild. The problem is some of the injuries suffered may be insidious, leaving a permanent but unnoticeable effect on the animal’s health.

We used resightings data on a population comprised of rehabilitated and wild birds to estimate their chances of survival and found that the rehabs have a significantly lower chance of surviving year on year (90% Vs 72%). By modeling different proportions of rehab and wild birds we showed that a 50:50 mix of the two groups is the threshold beyond which the population will decline.

That’s not to say that we think rehabilitation is a bad idea, it’s obviously better to get the bird back in the wild where it can contribute to the survival of the species than leave it to die from its injuries. Rather we suggest that vulture conservation should be focused on prevention instead. This is achievable. In India, farmers have stopped using drugs on their cattle which poisoned the vulture population en masse. Pylons and turbines can be equipped with signals that alert the birds to their presence.

Conservation practice coupled with a scientific understanding can only better our ability to stop the slide to extinction.

Author: 

Adam Kane, kanead[at]tcd.ie, @P1zPalu

Photo credit;

Phil Perry

Posted on

When Perseverance Pays Off

Takahe_noa

The history of science is, as the name suggests, the study of the historical side of science: the people, the process and the development of the knowledge and techniques that have made science the dominating force it is today. In popular culture the history of science is often told through individuals: the mavericks and geniuses so singular that only they could see the right path to take. The problem with this approach is that it does a mis-service to the hundreds and thousands of people who have worked so tirelessly to make the incremental advances in knowledge that accumulate until the snowball has built into an avalanche and the paradigm is ready to be shifted by whoever is lucky enough to see the pivot first (to hideously mix my metaphors).

Yet there are times when the ‘maverick’ status is not unwarranted. Often the term is used pejoratively to describe someone who will not let go of an idea long-since disproved. But on occasion there are people for whom the inability to give up pays off; and it’s one such person I wish to discuss here today.

The set-up: Otago, South Island, New Zealand, early 1910s. A boy stands in the local museum looking at an old black and white photo of a bird. This bird is unlike any he’s seen. It looks like a pukeko (a large moorhen-like bird) but it is maybe twice the size and three-times the bulk. It has a sharp yet heavy bill that takes up the entire front of the face; a stocky neck and strong bare legs. The legs and bill are the same colour but differ from the dark body. The feathers show signs of different colours on the back and wings though the black and white makes it difficult to be certain. The boy stares, enraptured, and looks at the label: Notornis (Maori: Takahe; Porphyrio hochstetteri): Extinct.

The boy was Geoffrey Orbell, and despite being told (probably repeatedly) that the takahē was extinct and had been since the 1890s, he continued to believe that they were still out there, hiding. Fiordland, the area where takahē were last seen alive, was still relatively unexplored and the mountains and valleys could easily hide a small population, or so Doc (as he was nicknamed due to his medical degree) believed. With a small group of friends he spent his free time tramping through the Murchison Mountains in search of the elusive (and supposedly extinct) bird.

I don’t know how long he searched, how many miles he tramped, how many friends he bored and how many false hopes he had dashed. But I do know that in 1948 he did what no one thought possible: he found a population of living takahē (the name now commonly used).

The discovery caused an immediate reaction and for a while Dr Orbell and his friends were international stars. Scientists hiked to the valley where the takahē had been found and, unusually for the time, recognised the importance of the discovery. Efforts to protect the birds were rapidly put in place. In a news report from 1950 (well worth watching for voice-over and musical accompaniment if nothing else) the population was estimated at 10 breeding pairs, yet this may have been an underestimate as the population was said to reach a low in 1982 of 118 birds.

Until the 1980s the takahē were largely left in peace but a steep decline in population numbers forced the New Zealand Department of Conservation (DOC) to step in. A captive breeding programme combined with translocation to predator-free reserves increased the population to 263 at the beginning of this year. This may not seem impressive for 30 years of active conservation but takahē, in common with many of New Zealand’s endangered birds, are classic K-selected species meaning they live a long time, are slow to reach maturity and have few offspring over the course of their lives.

Predatory rodents that prey on eggs and chicks and inbreeding depression are the main factors that hinder more rapid population growth. Luckily New Zealand has recovery strategies for many of their endangered species which involve the use of predator-free islands and mainland reserves. While little can be done to improve the genetic diversity, strenuous efforts are made to maintain it through closely monitored breeding programmes.

Takahē may not be completely safe from extinction, without active conservation they would almost certainly be extinct. If it were not for Dr Orbell and his passion and determination in the face of almost certain defeat it is highly likely that the takahē would have died out, high up in the mountains and with no one to mourn their loss.

Dr Geoffrey Orbell was an ear, nose, throat and eye doctor whose search for the takahē was just one part of his long and fascinating life. He died in 2007 at the age of 98 and was born on October 7th 1908. Happy Birthday Geoffrey!

Author:

Sarah Hearne; hearnes[at]tcd.ie, @SarahVHearne

Photo Source:

Wikicommons