On the Trail of Giants: Population Ecology of Giraffes in Tanzania

“Kuna twiga pale,” I say in Swahili to our driver Meshak. There are giraffes over there. My partner Dr. Derek Lee and I stand side-by-side in the back of our Land Cruiser, its top opened, and peer through our binoculars at a herd of Masai giraffes (Giraffa camelopardalis tippelskirchi) feeding on umbrella-shaped Acacia tortillis trees several hundred meters away. We are deep in the heart of Tarangire National Park in northern Tanzania, East Africa. “I see at least 12 giraffes,” Derek says. “Let’s head over there.” As our vehicle bumps across the savanna towards the herd, some individuals continue eating and milling around, while some lift their heads and watch our approach, serenely chewing their wads of cud. As long as we advance slowly and do not drive directly towards them, they are unconcerned.

A group of young male giraffes in Tarangire National Park

We carefully scan the ground for aardvark holes and logs hidden in the grass as we proceed forward. The closer we get to the giraffes, it strikes me how absurdly tall and oddly shaped, yet wonderfully elegant these majestic creatures are, the world’s tallest of animals. When we are about 70 meters from the closest giraffe, we swing the vehicle around to see her right side. Derek photographs her with our camera. I measure her exact distance away from the camera using a laser rangefinder, and record the photograph number, her distance from camera, and her sex and age class in our field notebook. Moving on to the other giraffes, we weave in and out of the trees and bushes, constantly adjusting our angle to get photos perpendicular to the animal. If we witness a nursing calf, we make a note connecting the cow-calf pair. We also record anything unusual such as signs of disease or injury. After everyone has been photographed, we mark a GPS location in the approximate center of the group, make a final count of all the giraffes, and follow our original tracks back to the road. As we drive off, the giraffes stare after us with their big, long-lashed eyes, chewing intermittently, but otherwise completely unfazed as we depart with more data points in our growing set of thousands of photographic giraffe ‘captures.’

A male giraffe in Tarangire National Park

Derek and I are implementing the world’s largest individual-based demographic study of giraffes in terms of sample size and area sampled. We conduct six surveys per year towards the end of each of Tanzania’s three precipitation seasons, with every survey lasting about 10 days. We are investigating births, deaths and movements of giraffes in the Tarangire ecosystem—a region undergoing rapid anthropogenic land-use changes—to understand where they are doing well and why, and using that information to conserve declining giraffe populations. For my PhD in the Program Ecology at the University of Zürich, I will be using our photographic capture-recapture data to study giraffe natal dispersal patterns and to quantify the fitness consequences of their social dynamics. I am part of both the ‘Population Ecology’ and the ‘Cooperation and Social Structuring in Mammals’ research groups.

Monica Bond holds a giraffe skull
Dr. Derek Lee photographs a giraffe for identification in Tarangire National Park

Despite being an African icon and one of the planet’s last mega-herbivore species, giraffes remain understudied in the wild. In part, this is because giraffes were not intensively hunted until recently in some areas: they don’t produce tusks or horns that are coveted as trophies or medicine and they are not an aggressive species. Sadly, however, giraffes are becoming increasingly endangered throughout their range in sub-Saharan Africa due to conversion of savanna woodland habitat to agriculture, deforestation for charcoal, and bushmeat poaching.

A giraffe browses on Acacia

Giraffe numbers have plummeted across Africa by an estimated 40 percent in the last few decades, to the point where they now number far fewer than African elephants. The IUCN recently upgraded the species Giraffa camelopardis to “vulnerable” on the Red List (while scientists are debating the number of species, all giraffes are currently still considered to be one species). Most giraffe populations are now largely restricted to lands in and around national parks. Predation by lions and hyenas also can negatively affect giraffe survival—a natural phenomenon that becomes a problem as wildlife are squeezed into small protected areas.

Lions prey upon giraffe calves and sometimes adults

After decades of little research on the wild giraffes, scientists are showing renewed interest in these gentle giants because of their declining numbers. Derek and I began photographing individual giraffes in 2011 to build a database of demographic information on giraffes across the Tarangire ecosystem. This region, which contains two national parks and a large private ranch embedded within a matrix of village lands, is known for its extraordinary diversity and abundance of large mammals including giraffes, elephants, zebras, antelopes, lions, and leopards, but these magnificent animals exist in a landscape undergoing rapid changes.

Drinking can be awkward for a giraffe

The Tarangire ecosystem is second in giraffe density only to the nearby world-famous Serengeti ecosystem, but unlike the Serengeti, land in Tarangire is largely unprotected. Since the 1940s, human population and agricultural expansion in Tarangire have increased fivefold, causing substantial habitat loss and fragmentation. Bushmeat poaching is also a serious problem—recent research suggests that each year poachers kill about 90 giraffes in just one small part of the Tarangire ecosystem. Giraffes are hunted at night, dazed by spotlights or confused by loud horns and killed with machetes or spears; giraffes are also targeted with wire neck snares set high in the tree canopy.

Monica Bond speaks with local Masai tribal members

We study wild giraffes using two technologies, digital photography and pattern-recognition software, to identify and track individuals by their coat patterns. Every giraffe has unique and unchanging spot patterns, much like the human fingerprint. These patterns enable us to identify and monitor individual giraffes with the aid of a computer algorithm that matches the thousands of photographs we collect during our surveys. We can determine where and when we last saw the animal, whether a female was pregnant or nursing, and who else was in the herd. Demographic studies of uniquely patterned species using the non-invasive photographic method have grown in popularity as digital cameras and pattern-recognition software have improved. These technologies allow us to compile demographic data on thousands of giraffes—sample sizes unheard of in the days before computers. The method is also much less expensive than physical captures for marking of large mammals, and is entirely non-invasive and non-traumatic. Other recent demographic studies using pattern-recognition software with digital photographs have been conducted on wild dogs, wildebeests, and even toads (my UZH colleagues Sam Cruickshanck and Benedict Schmidt just published a study on yellow-bellied toads in Switzerland using the same pattern-recognition software that we use).

Wild ID pattern-matching computer software

To date we have identified and are monitoring over 3,100 individual giraffes. We aim to understand factors affecting survival and reproduction in landscapes subjected to different human uses, including parks and village lands, and also to identify important calving grounds and critical movement pathways. My PhD research will help ascertain how human and natural factors influence sociality and fitness, and how these mega-herbivores move around the ecosystem, which will provide insights into what may be the most effective conservation measures. The ultimate goal is to enable healthy populations of giraffes to continue roaming across this ecosystem as they have for eons, fulfilling their important ecological functions and delighting humans for generations to come. The Masai Giraffe Conservation Demography Project is being conducted by the Wild Nature Institute. Visit their website to learn more.

Giraffe calves in Lake Manyara National Park

The Sixth Bio-Logging Symposium, Konstanz – Through the Eyes of an Engineer II

A personal account of #BLS6 by Pritish Chakravarty

(who is also the recipient of the most exciting award ever!)

The work field biologists do and the places they do it in blow my mind. The first time I wrote a “Through the Eyes of an Engineer” article was when I went to the Kalahari for the first time, and I thought I had seen all the amazing things that I would ever see in this life. I was happy and ready to settle down and tell my grandchildren these stories while they pulled my contentedly whitening hair. Well, being in Konstanz this past week for the Sixth Bio-Logging Symposium changed all that. With an enigmatic smile, Life brushed away the curtains in front of one of the rooms I hadn’t yet set eyes upon, and streaming rays of awe poured in and filled my consciousness.

The Bio-Logging Symposium is an international conference held every three years where people present findings and techniques related to data obtained through sensors put on/in animals. I’m writing this little piece as a memory of the unbelievable things I saw during this conference and the inspiring people I had the good fortune of meeting and talking to.

Coming from an engineering background, I’ve been conditioned to a world of buildings, shops, computers, graphs, apps and algorithms. This was the world my daily consciousness resided in and took for granted. This conference took this world and compressed it to a pixel in one of the frames of the feature films that is the biological planet we live on, and that’s hidden (fortunately, perhaps) from the eyes of city-dwellers like myself.

I have seen things during this conference that I did not even think about dreaming of. A map of the globe centered around Antarctica was shown in the very first keynote talk by the legendary Gerry Kooyman, who’d spent his entire life working with various animals in the white desert that is the Antarctic. Imagine if you got lost near the South Pole and came across a friendly seal and asked it for directions. Whatever place you’d ask for, the seal would just say, “Oh, it’s up north”, and it would always be right! Talking to Gerry Kooyman a few days later made me rethink the physical references we always take for granted. I asked him how people in the Antarctic managed to avoid crevasses hidden by deceptive, flimsy layers of superficial snow. In response, he told me how broad the issue really was. They could, in fact, not even pinpoint where the horizon was – where the ice ended and where the sky started was anybody’s guess. Even entire hummocks (ice “hills”) would be rendered invisible by the near-complete lack of contrast! Recounting one such episode, he said that once, while driving around in his snow-mobile, he noticed that the engine started straining, and despite going full-throttle, the speed was just not as high anymore. Steeling himself against a slowly sinking heart, fearing a vehicle malfunction, he kept going, and noticed after a while that the engine was back to normal. Curious, he said to himself. He later realised that he’d ridden over a hummock without even seeing it! Recounting a second other-worldly phenomenon, he said he would often chase the green lights of the Aurora Australis on his trusty snow-mobile as they passed over the Antarctic over several minutes.

I saw videos from cameras attached to the backs of elephant seals! Using these cameras, researchers working with National Geographic found that elephant seals would go down to the ocean floor, much lower than they’d earlier expected, to hunt for lobsters scurrying around. This was the first solid proof that protected areas defined for the seals by neighbouring countries needed to extend all the way down to the ocean floor, since the seals will anyway go there to forage, and the protection would only mean something if the entire area traversed by these seals was covered.

As if watching the ocean floor from an elephant seal’s point of view wasn’t spectacular enough, I also met someone from a group in California who put cameras on the back of a blue whale. A blue whale, can you imagine?! For the first time, I got a faint semblance of just how big it really was, and how surprisingly mobile it was for its size. It reminded me of how one has a brief moment of surprise when a plump person turns out to be an excellent dancer. In the video, the blue whale, which one often forgets is actually a predator, made its way determinedly towards a school of fish that had arranged itself into a spherical shape. Approaching the fish, I watched with a quickly dropping jaw as the blue whale reared its head up and opened its gargantuan jaws and swam right through the centre of that school of fish, gobbling up several of them in a single go! This group of researchers had also put gyroscopes and accelerometers on the blue whale along with the camera and saw how these beautiful, massive beasts made banked turns (where they not only turned their head to turn, but also rotated their body around the head-tail axis to make the turn at high speed) during hunting, and slower turns when they were simply sauntering along. What was quite surprising for me was that they actually used the accelerometer and gyroscope to understand what they saw in the videos! In any usual scenario, like with my study with the meerkats, one looks at the video first, observes the activity being carried out by the animal, and then tries to understand the signals recorded by the accelerometer. Puzzled, I asked them what required them to trust the accelerometer and gyroscope more than the video, and they then showed me a video that blew my understanding of deep underwater environments to smithereens. When you are a hundred metres underwater, it is extremely difficult, if not impossible, to gauge just from a picture of the water (from the camera attached to the blue whale) which way is up and which is down! How surprising! Only in some videos, the Sun shone through, and the top part of the video was slightly brighter than the bottom part, and so we could tell which direction was which. The sensors (the camera, inertial measurement units, pressure, temperature and light intensity recorders) were arranged in a cuboidal device with four suction cups on the bottom surface. These suction cups would be attached to the whale’s body. Sometimes, they said that the whale’s skin was as smooth as glass, and the unit would just slip down because the suction cups would just not hold. Other times, the blue whale would just shed a lot of its outer skin, and the cups would get detached along with the shed skin. So many practical challenges! How cool, how awesome! Phffff, I still can’t come to terms with watching the ocean from a blue whale’s perspective!

I learned that polar bears were great swimmers, and that they were truly ‘marine’ mammals. A study in the Arctic waters found a polar bear that swam for seven hundred kilometres straight, continuously over several days! They also showed a rather endearing picture of a little polar bear cub perched atop its mother’s back as it piggy-backed across the frigid waters with its mother swimming at the surface. Since the cubs were smaller and had lesser fat reserves than adults, they couldn’t venture out into the water alone at such an early age – they would just freeze to death otherwise!

Another talk gave, apart from other cool information on Arctic foxes, anecdotal evidence of just how powerful their olfactory senses might be. A truck transporting salmon in Norway had an accident and all the salmon fell in a heap on the ground. The next day, trotting over from more than a hundred kilometres away, a small group of Arctic foxes starting from Sweden had found their way to this site, and happily feasted on this lucky find. Comparing that to human olfactory abilities, I’m generally quite relieved when I realise I need deodorant before others around me start to agree.

Another professor told us about how adult vultures were experts at climbing thermals (to gain altitude in the most energetically efficient way), and how juvenile vultures tended to not do so well, as they would flap their wings at the wrong moment during the ascent and consequently be left far below the adults who were climbing the very same thermal with consummate ease. The adults were apparently very adept at choosing just the right moment to turn their body (approximately every 7 seconds) as they moved upwards in spirals, and the timing of the juveniles was probably off. In fact, that professor actually went on a sabbatical to Australia (or was it New Zealand? I forget) to learn how to fly a glider, and said that the world champions training at the same club he was taking lessons at had independently (probably) figured out that the ideal way to climb the thermals in that part of the world was also to twist the glider around in a spiral and wait for the right moment to turn! Amazing how these vultures had perfected this technique, and that nature had figured out the perfect way to do it all by itself!

Some other examples of the amazing abilities of diverse animals – a researcher using a barometer attached to the back of a sperm whale (I’m going to stop saying just how unbelievable it is that people actually get to interact with such creatures as part of their daily job! “Hey, how was your day?”. “Oh well, you know, the usual. Woke up at 7 am, had some breakfast, popped into the ocean to tag a sperm whale. You?”. “Uh, never mind…”) measured a dive-depth of 3526 m below sea-level (I’m sure about the 3 and 5, but perhaps not about the 2 and 6), which is the deepest dive-depth of a sperm whale measured till date. Three-and-a-half kilometres below sea-level – I’ll probably not be able to hike that distance in an entire day! That’s just unfathomable! Quite literally, I suppose. She did caution us about the precision of this number, since the barometer was close to the maximum amount of pressure that it could measure. Awe is oozing through my nostrils, and I don’t even have the flu.

Another story from a professor from Switzerland tells of a ‘plain, old’ hoopoe flying at a height of 6000 m! Six kilometres above sea-level! That’s as high as mountains in the Himalayas! It must have climbed a (or multiple) thermals on its skyward journey, the professor said.

I learned something else that turned my understanding of the world on its head. Magnetic fields affect the photoreceptors (rods) in our retina, and that modifies the images we see. It could, for instance, introduce a pattern of two broad intersecting lines superimposed on our ‘normal’ field-of-view. The Earth’s magnetic field does this to some animals, and the images that they see when they’re oriented in the north-south direction are apparently slightly different from those they see when they’re oriented in the east-west direction. However, there seemed to be much debate about whether animals actually use these directional differences, and how much of an impact this actually had on animal behaviour, and about how much we could really conclude from the experiments that were done to explore this in foxes.

Experiencing these hitherto hidden corners of the world vicariously through cameras installed in unlikely places has changed my understanding of the world, and the way I felt about this field. I thought I really enjoyed signal processing, and that understanding meerkat behaviour from acceleration data was a beautiful application of it. But this past week made me realise that actually seeing these beings as they go about their daily lives gives birth to a simple, pure feeling of empathy that does not have any logical reason or goal behind it. So many times we hear about heroic animal conservation efforts in articles and interviews, and it does leave us with a warm and fuzzy feeling about the good in humanity, but doesn’t really touch us. Seeing these animals myself over this last week, and actually coming into contact with the people studying with them and hearing them talk about it sort of cracked an outer shell I had in my mind about bio-logging and animal conservation. It is not something separate from our daily lives, not something that happens far away in an unseen corner of a world that doesn’t concern us. People are not unfeeling or self-centered either – they have just not seen! If we could all just simply see the marvel of life around the planet, just simply observe these beautiful beings going about their daily business, we would all just sit with tears streaming down our faces – tears that come from places beyond reason and logic and goals and structure. And empathy would awaken… just like that.

I realised that this was an extension of what the mystic masters say about human life as well – we only feel a need to protect ourselves at all costs (which gets manifested as fear, aggression, comfort- and power-seeking) because we believe in a false sense of identity (our body, our country, our religion) that separates us from the rest of existence. What if all of us were Existence itself? Carl Sagan’s quote comes to mind: “We are a way for the cosmos to know itself”. We are the cosmos itself, and keeping it in good health (as far as our influence extends) is just as natural as perhaps brushing our teeth or taking a bath!

I did not add photos to this post because of two important reasons. First, it’s the difference between watching a film and reading a book – the film feeds you images and doesn’t give you the opportunity or the time to imagine stuff on your own. When you read, however, you stop and visualise, and the work your neurons do to create these inner images opens the doors to memory and emotion (that’s my own opinion, of course). The second important reason why this post doesn’t have any pictures is because I didn’t click any. 🙂

PS: Here’s a brief description of the keynote speakers, and here’s the book of all the abstracts from the conference. And here’s a huge wave of gratitude to the organisers for making this event possible, and for giving me the opportunity to be a part of it.

Tracking down an African wild dog den

The winter months of June, July, and August mark the coldest period of the year in Northern Botswana. It is this cool period that African wild dogs choose for whelping, as pup rearing is energetically costly for a pack. Typically, the dominant female looks for a suitable den site, such as an abandoned aardvark hole, where she will give birth. As the mother is obliged to stay at the den to nurse and protect the pups, so the survival of both the mother and pups is fully dependent on the other pack members during this critical period. The rest of the pack all leaves the den site once or twice per day to go hunt, and upon returning, they regurgitate part of their freshly caught meal to feed both mother and pups.

During the denning period, the normal ranging radius of a pack is drastically reduced. Consequently, denning season is the optimal time of the year to locate the study area packs and for pack monitoring. This July we tried our luck to locate the den site of the missing ‘Mula’ pack. This pack was formed in February 2016 by the joining of a male dispersing group with a female group, each of which we had monitored with satellite collars as part of our ongoing research project on African wild dog dispersal. However, these satellite collars both had dropped off by now. As we are also interested in the settlement and reproductive success of recently formed packs, it was critical to catch up with this pack again.

Having no working radio telemetry collars on the pack we were left with no other option than to track down the pack on the ground the old-fashioned way. We already knew that the new Mula pack’s home range extended from Xakanaxa all the way east along the Khwai river to North Gate of Moremi Game Reserve. This meant they could theoretically have been denning anywhere within about 400 km2 and along a stretch of about 50 km. We decided to start our search mission in Xakanaxa where frequent sightings of 12 wild dogs had been reported on the sightings board at Moremi South Gate. The last time we saw ‘Mula’ pack, at the end of 2016, they were ten adults plus two pups. Therefore, these reports sounded promising.

With enough supplies to spend a couple of days away from our research camp, Ed, a Research Technician at Botswana Predator Conservation Trust (BPCT), and I set out for the 50 km drive to Xakanaxa. Upon arrival, we bumped into some safari guides who told us that they had regularly seen a pack of 10 wild dogs and one male was wearing one of our radio collars. Luckily, one of the guides had just seen the pack earlier that morning. Using this information, we started looking for fresh tracks on the main road and soon found some. The prints were following the road for roughly 3km but eventually they left the road and we lost their tracks. We decided to park our LandRover close to a crossroad to see if the pack would use the same road on their way out of the presumed den site for the evening hunt.

Our car parked next to the road in anticipation of the ‘Mula’ pack coming along on their way out of the presumed den site.

Being impatient, we left our lookout before sunset and looped around to the North the nearby Paradise Pools to search there. With no success, we drove back to the crossroad to find out that the pack had just come by, as indicated by the many fresh tracks on the road. We rushed following the tracks and caught up with the pack shortly after. They were spaced apart and due to the progressing darkness, we were not able to count more than eight individuals. As we were taking photos of them for identification, one of the dogs who was lagging behind suddenly turned back and sprinted down the road toward where they just came from. We followed him as we guessed he might have changed his mind and decided to return to the den. He ran down the road at full speed, coming by our stake out place at the crossroad and then continued heading further south. Then suddenly, he turned east into the thick mopane bushes. It was too dark for us to try to follow him through the thick vegetation, we took a GPS fix of where he turned off and went off to find a suitable spot to spend the night. Later that evening we confirmed by examining our photos, that these were indeed the remaining members of ‘Mula’ pack.

Our first encounter of ‘Mula’ pack as they were trotting along to road for an evening hunt.

Early the next morning, we positioned the vehicle again at the crossroad in hopes that the pack would come by again. Unfortunately, no dogs appeared and we had to conclude they must have chosen a different route. Just as we were about to leave, another game drive vehicle pulled up and told us they had just seen the dogs back on the airstrip again heading east – which meant towards where we saw them last night. In anticipation that the dogs would continue running in a straight line, we drove south on the main road and parked close to where the extension of the airstrip would intersect the road. Luckily, we were at the right spot as a group of six of them came out of the thicket and crossed the road. We immediately followed them into the bush. Despite many obstacles, we managed to stick with the dogs for roughly 300m. But then, suddenly, we lost them in a relatively open area. We got out of the car and started looking for fresh tracks. There were quite a few prints on a small game trail. By following them, we ended up in a sandy rift with spaced out apple-leaf trees. Unfortunately, the sand was very deep which made it hard to surely identify any of the many tracks as being from wild dogs.

A subgroup of ‘Mula’ pack crossing the road on their way back to the den site

For the next three days, we continued our search but never managed to close in further to the potential den site. We usually lost track of the dogs in deep sand. As we were running low on supplies, we eventually decided to head back to our research camp. But this didn’t mean that we were giving up. Too close were we in finding the den site to call our mission a failure.

One of the identification photos we took of the ‘Mula’ pack dogs after we bumped into them early one morning.

A few days later we drove back to Xakanaxa early in the morning accompanied by ‘Tico’ McNutt, founder and director of BPCT, who has decades of experience in tracking wild dogs. He seemed quite confident in finding their den based on our preliminary efforts in narrowing down the search area. As we approached Xakanaxa, we drove to the spot where Ed and I lost sight of ‘Mula’ pack previously. Tico got out of the car with Ed and me following. He first circled around the spot in a wide loop in search of any fresh tracks. Once we closed the loop he headed for the direction where he must have seen the most promising tracks. Shortly after, he showed us fresh dog tracks and pointed towards the direction they were leading. After about 1.5 km we approached an open sand ridge. Tico told us to stick close together as he was confident of the den being nearby. We followed the fresh tracks in deep sand, and as we were approaching a few apple-leaf trees we suddenly heard the alarm bark of a wild dog. This was undoubtedly the den site we had been looking for. We crouched down but weren’t able to get a visual of the dog as the trees were quite dense. We decided to take a GPS fix and return with the vehicle.

Impressed by the way Tico tracked down the den in no time, we started heading back. After a few steps, he stopped and showed us animal tracks in deep sand. What seemed like it could have been any track to Ed and me, was definitely the spoor of a wild dog according to Tico. He pointed out that he could detect wild dogs in deep sand based on their gait. Two feet are always placed close together with a bigger gap between the next set of pads whereas the step lengths of hyena prints are generally more regularly spaced. This was an important lesson for us and definitely made the difference as Ed and I were constantly losing the dogs in soft substrate during our previous search efforts.

Wild dog tracks (left) are not always as distinguishable from hyena tracks (right). As the substrate gets softer, details of the paw vanish quickly. We learned from ‘Tico’ that it comes down to look for gait patterns such as spacing between the footprints in deep sand.

On our drive to the newly-discovered den site we were not able to see more than half a dozen of the adult dogs nor to get a visual of any pups. But when Ed and I drove back to the den a few days later, we managed to identify all ten adults, the two yearlings, and watch twelve new-born pups play youthfully outside the den. It was well worth the effort:  No dogs had died since our last detailed encounter with the pack seven months ago and a promising number of pups was about to grow up.


Watch the ‘Mula’ pups as they emerge from the den:

 

Find out more about this project by visiting our research page:
African wild dog dispersal and demography

Amphibian Conservation Research Symposium

Last week, I headed off to the University of Canterbury in the UK to present at the Amphibian Conservation Research Symposium. This is the fourth year that I’ve attended this meeting ,which aims to bring together researchers from all around the world working on all facets of amphibian conservation.

 

 

 

The attendees in Canterbury
Photo credit: @AmphibianCon

 

For me, the meeting is always one of the major highlights of the year; an opportunity to get out of the office and network with a crowd of incredibly diverse people united with an infectious passion for amphibian conservation. As I’m in the final months of my PhD (and am therefore chained to my computer frantically writing up my thesis) this year was particularly rejuvenating- giving me a chance to live vicariously through the experiences shared by my fellow attendees. I may not have the time to do any fieldwork this year, but hearing about people scuba diving to discover the breeding ecology of critically endangered frogs, or using drones to survey bromeliads for cryptic amphibian species, cannot fail to inspire.

 

 

Undoubtedly a new life-goal for me: Arturo Muñoz Saravia surveying breeding behaviour of the Titicaca Water Frog through high-altitude scuba diving
Photo credit: @TetZoo

 

ACRS always aims for a very broad mixture of talks, and this year was no exception. Topics spanned research into animal husbandry, infectious diseases (always necessarily a major topic in amphibian research, sadly), monitoring for cryptic species, and species’ reintroductions, to name just a few. These were complemented by a great set of keynote speakers. This year the key message I took from these talks is just how large and co-ordinated the amphibian conservation community is. Keynote talks from Anne Baker and Phil Bishop reminded me that although applied conservation often seems like working in a small-scale bubble, there is a whole alphabet soup of organisations (ASA, AArc, IUCN SSC ASG….the list is as endless as it is bewildering) co-ordinating across the globe to improve the fate of amphibians.

 

 

 

Penultimate talk of the conference: when can we rely on analysis of amphibian count data?
Photo credit: @AmphibianCon

One great aspect of ACRS is their Future Leaders programme: each year, the committee funds the attendance costs of several early-career researchers who have made substantial achievements in amphibian conservation in their host country. This years’ leaders hailed from Nepal, Brazil, India and South Africa, and each gave great presentations and insight into working in countries where things operate very differently to Europe! Particularly notable was Sethu Parvathy’s impressive and hilarious one-woman theatre performance of the persecution of frogs in cardamom farms in India (simultaneously from the perspective of farmers, frogs and rats), and the inspirational work of Luis Marin da Fonte. His involvement in discovering the only known population of a species new to science (the aptly named Admirable Red-belly toad) and securing protection of this site by successfully campaigning against the building of a hydroelectric plant upstream from the population, drew a spontaneous round of applause from the audience.

 

 

 

ACRS Future Leaders; Biraj Shretha, Luis Marin da Fonte, Sethu Parvathy and Fortunate Phaka
Photo credit: @AmphibianCon

 

My contribution to the meeting was a talk warning of the pitfalls of analysing count data; as the penultimate speaker on the last day of the conference, giving a talk on population modelling to a tired audience seemed like an uphill battle. However, I was happy to be approached by several people after the talk who were interested in my solution to the issues of non-closure in count data, and I hope that some fruitful collaborations will result from the meeting.

 

The inspirational story of the Admirable Red-belly toad
Photo credit: @AgentAmphibian

 

 

Thanks to the organisers at the University of Canterbury for organising another great conference! And also to Darren Naish of Tetrapod Zoology for writing up this great summary of the conference.

 

Shrinking whales and warning signals

As with, I suspect, an embarrassingly high number of scientific papers this one was conceived over a mug of something warm and caffeinated, but unlike most of my other publications I finally have something charismatic to talk about!

 

Whales are big news (pun intended), and the commercial hunting of whales is a sensitive and emotive topic, with what could probably be described as a collective embarrassment regarding the mass slaughter carried out during the 20th centaury, and subsequent collapse of global whale populations. However a by-product of this generally frowned upon practice – and some frankly anally retentive bookkeeping – is an exceptional and unique record of the whales caught during this period. The International Whaling Commission required a record of all whales hunted, the approximate location of their capture, as well as details on their size to be noted down. The net result is a staggering record of over 2.8 million individual whales harvested from 1900 onwards.

Now the reason I know all of that is because of that caffeinated beverage in a small café in Hobart, during a visit to the University of Tasmania’s Institute of Marine and Antarctic Research. The idea behind the visit was to test the effectiveness of a method for predicting population declines that incorporated classic abundance based early warning signals1,2 along side shifts in trait dynamics3 on data from real-world population collapses. Our original intention was to simulate population collapses due to overharvesting and look for early warning signals (EWSs) before the collapses occurred. However one of the key aims of EWSs is to make them applicable to species of conservation interest, and whilst brainstorming the best way to approach this we realized that data might already exist which would allow us to test these methods – data that describe the dynamics of populations prior to documented collapses, that include information on the body size of individuals. And thus this Nature Ecology & Evolution paper was born – where we identify both abundance based and trait-based EWSs up to 40 years prior to the collapse of whale populations.

For me a few really interesting secondary results came out of this. The first was the sheer scale of the whaling effort during the 20th centaury – at its peak over 30,000 Blue whales were removed in a single year, with similar peaks seen in the other three species we looked at. So perhaps it shouldn’t have been as surprising as it was to see dramatic changes in the body size of these whale populations – a decline of over 4m in Sperm whales caught over a 80 year period. What is fascinating to me is the interaction between the ecology of each species and the techniques developed to hunt whales, and how this impacts the trend in body size over time; Sperm whales decline in size consistently through time, probably because they are relatively slow moving, where as for faster species landed body sizes initially increase (in line with technological advancement4) and then decline as all the large individuals are removed.

This paper felt in many ways cathartic – that we can use this data from a barbaric period of commercial excess to develop and test methods that might be applied to the current diversity crisis feels good. And whilst we are still a long way from making perfect predictions about the fate of biodiversity in the Anthropocene, every step towards this goal helps.

The paper in Nature Ecology & Evolution is here:

http://go.nature.com/2skjWUY

 

This paper was made possible by a Swiss National Science Foundation International Short visits grant, and an ERC Starting grant (#337785) to A.O

 

References

  1. Dakos, V. et al. Methods for detecting early warnings of critical transitions in time series illustrated using simulated ecological data. PLoS One 7, e41010 (2012).
  2. Scheffer, M. et al. Early-warning signals for critical transitions. Nature 461, 53–9 (2009).
  3. Clements, C. F. & Ozgul, A. Including trait-based early warning signals helps predict population collapse. Nat. Commun. 7, 10984 (2016).
  4. Basberg, B. L. Technological change in the Norwegian whaling industry. Res. Policy 11, 163–171 (1982).

 

Movement Ecology Summer School – August 2017

It is our pleasure to announce the 2017 Movement Ecology Summer School (MESS) organised through the Life Science Zurich Graduate School, PhD Ecology Program. The MESS will be held in Faido (Ticino, Switzerland) during 27.8 – 1.9.2017.
The course builds on the expertise and positive feed-backs of the past summer schools. For this year too, we were able to secure the participation of leading scientists in the field of movement ecology and remote sensing:
Dr. Gabriela Schaepman-Strub (Zurich University)
Prof. John Fieberg (University of Minnesota)
Prof. Luca Börger (Swansea University)
Dr. Gabriele Cozzi (Zurich University)
 
This one-week course covers several aspects of animal movement ecology and includes both theoretical and conceptual and practical sessions. The course builds on analytical complexity and leads the participant through several steps. During day one, the participants will learn to source landscape information through available remote sensing imagery and to import, manipulate and represent geographical data into R. Day two will be dedicated to the decomposition of movement trajectories and characterisation of movement modes and phases. During day three the participants will be exposed to common methods used in the calculation of home ranges and discuss the pros and cons. During the next day we will use presence/absence data to analyze habitat selection. Finally, during the last day, the participants will be exposed to some new tools and methodologies to include data from alternative sensors (e.g. accelerometers) in the study of animal movements. Fundamental aspects such as study design, spatial autocorrelation, sources of error and time varying covariates will be discussed. Data sets will be provided but the participants are encouraged to bring their own data. Active participation during the course is required to obtain 2 ECTS credit points.
 
Please note, this course is organised for PhD students of the Life Science Zurich Graduate School. Priority will be given to students registered in the PhD Program in Ecology, however PhD and MSc students from other universities may attend if there are available places. 
 
Please do not hesitate to contact me (gabriele.cozzi@uzh.ch) for further information

Where can the wild things roam? Combining ecological suitability and human acceptance for the Swiss wolf.

About one third of the Swiss landscape offers suitable wolf habitat. Nonetheless, there is only a small fraction thereof where the wolf is tolerated by local communities. Those regions – characterized by both favourable environmental conditions and a positive attitude towards the wolf – are identified as candidate regions for the successful short to medium-term wolf expansion, according to a study conducted by the population ecology research group at the University of Zurich

©RamiroMarquezPhotos / iStock

The wolf was eradicated in Switzerland and from large parts of continental Europe including France and Germany by the end of the 19th century. Following legal protection, the wolf population started naturally increasing and expanding, and in 1995 its presence was confirmed in Switzerland. Sightings have increased since. Despite 13’800 km2 of Switzerland are characterized by favourable conditions such as large forests with little human pressure and have thus been identified as suitable wolf habitat, wolf expansion in Switzerland has been substantially slower than in other parts of continental Europe. As the wolf is more and more subject to human-dominated landscapes, scientist at the University of Zurich developed a novel method that integrated both ecological and human components to identify regions with favourable environmental conditions and where the wolf was tolerated.

Mapping human acceptance of the wolf to identify suitable socio-ecological areas

socio-ecological suitability model
Combining human acceptance (a, c) and habitat suitability (b, d)
helps identifying socio-ecologically suitable wolf habitats in Switzerland (e).

About one third of 10,000 randomly selected residents in Switzerland participated in the survey. Combining the response from questionnaires with geographical information, Dominik Behr and his team created a nationwide map of human acceptance. Acceptance decreased with increasing altitude of residency and even more so where high numbers of sheep and goats were held. Acceptance increased with increasing distance from confirmed wolf presence and in densely populated areas. People who perceived the wolf as dangerous to humans and harmful to livestock and wildlife mainly opposed the wolf. Younger people, and people who believe that the wolf had a positive influence on the ecosystem had a more positive attitude towards the predator.

“When we overlapped our human acceptance map with a habitat suitability map for the wolf, we realized that only about 6% of Switzerland was characterized by both a positive attitude and favourable environment conditions. This was in contrast to results from the habitat suitability map, which returned one third of the Swiss landscape as being suitable for the wolf” said Dominik Behr. “As wildlife biologists, we are good at understanding the ecological factors determining the suitability of a habitat for a wildlife species. Due to ever-increasing overlap between human and wildlife, however, we are obliged to take into consideration how human acceptance modifies our ecological description of habitat suitability. This study demonstrates one effective way to do this.” stressed Arpat Ozgul, professor of population ecology at the Department of Evolutionary Biology and Environmental Studies at the University of Zurich, and co-author of the study.

A novel framework to manage wolves and people
The socio-ecological map created by Dominik Behr and his co-authors appears to accurately represent the wolf situation in Switzerland of the past years, including identifications of areas of high, moderate or limited conflict. “By capturing areas characterized by both favourable environmental conditions and a positive acceptance towards the wolf, our approach is a valuable tool to identify overall socio-ecological suitable areas for the wolf. Under given conditions, those regions are good candidates for the successful short to medium-term expansion of the wolf. Additionally, this approach allows to identify key regions where proactive and targeted socio-ecological management plans and a constructive dialog among different stakeholders are needed” said Dr. Gabriele Cozzi, who coordinated the study.

Special thanks go to the 3142 people that returned the completed questionnaire – this study would not have been possible without their contribution.

Behr DM, Ozgul A, Cozzi G (2017) Combining human attitude and habitat suitability: a unified socio-ecological suitability model for the wolf in Switzerland. Journal of Applied Ecology