Snapshot Rhinos

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One of the animals that continue to be a rarity on snapshot Serengeti is the rhino. We have had a handful of capture events over the years.

There are two species of rhino found in Africa; the white or square lipped and the black or hook lipped. The Serengeti is home to the latter. It is a large bulky mammal and as such many a hopeful #Rhino has turned out to be a blurry image of an elephant or buffalo.  Things can get confusing with some of the images but isn’t that half the challenge trying to guess those indescribable blobs? Surely it wouldn’t be the same if everything was easy to id?

Anyway back to Serengeti rhinos.

Just 50 years ago between 500 and 700 Eastern Black Rhino (Diceros bicornis michaeli) roamed the Serengeti-Mara ecosystem but during the seventies the population was decimated by poaching to around 10 or so individuals.

A huge effort is being made by various conservation and government bodies with enormous donations by private individuals to save the population from total extinction. Notably a remnant population in the park was highly protected and slowly, over the next few decades the population made some recovery. In 2010 it was decided that the Serengeti area was being protected well enough to try and bolster the resident rhinos with new genetic stock. It just so happened that a private owner in South Africa had a breeding herd of Eastern black rhino that had been part of the attempt to safe guard the subspecies back in the 60’s, these animals had originated from Kenya. With strict controls by IUCN officials it was deemed these animals were of the right genetic stock to be reintroduced to the Serengeti.

The plan was to translocate 32 rhinos over the next few years and release them in a new site close enough to allow some overlap with the resident 30 or so rhino. Unfortunately the project has been affected by the recent escalation in rhino poaching and it is difficult to find how many rhino have been successfully translocated to date let alone the current Serengeti total population but you can bet it is still small. The IUCN red data list states Tanzania as having 88 Eastern Black Rhino in 2011.

If you are lucky enough to stumble across a rhino capture on Snapshot Serengeti you should definitely celebrate … and don’t forget to # it.

The Challenges of Field Work

 

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Hazard of the job; catching myself on camera-trap

 

If you have clicked through the seemingly endless captures on Snapshot Serengeti then you must have realized just how many cameras are snapping away out there in the Serengeti. Have you ever wondered who looks after those cameras?

Researchers sometimes go to extreme lengths to collect their data and not much deters them from their goal.

On a recent assignment working in Central African Republic I was tasked by our biologist to collect in an array of 40 camera-traps. The park was very large, the size of Wales and very remote, the nearest village was a 12 hours 4×4 drive away. It was also newly proclaimed and had little in the way of infrastructure like roads. Of course, Thierry wanted to survey the areas we didn’t yet know so obviously the cameras were nowhere near any of the smatterings of roads.

He presented me with a mobile phone resplendent with a mapping app which showed the camera trap locations overlaid with our rudimentary road network. I should really say temporal track system as these so called roads consisted of two tire tracks driven through the elephant grass and mud soon to grow over again in the coming wet season. The park consists of a mosaic of wooded savannah and tropical lowland rainforest so you are either struggling through 2 meter high elephant grass or deeply tangled riverine forest growth. Added to the physical challenges of working in the park was the fact of it harboring armed Sudanese cattle herders, poachers and Lord’s Resistance Army militia.

So equipped with the mobile phone, two trackers and 5 armed rangers off we went to collect the cameras. After three hours bumpy ride plagued with biting tsetse fly we got as close to the first camera as any road was going to take us. Using the phone to navigate I pointed us in the general direction praying that the battery would last. If it failed we would be completely lost with no landmarks. Two kilometers later we had narrowed down the camera location to about 20 meters and under the vigilant eye of the rangers myself and the two trackers began searching for the camera in the thick jungle tangle.

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Rangers caught on camera-trap whilst on patrol 

 

Once the camera was reclaimed it was bagged up and we set out for the walk to the next camera another kilometer or so away. The whole day was spent battling foliage and insects in the 40o c temperatures for a total of 8 cameras. We made camp for the night; the journey back to base was just too far with so many cameras still to collect. It took 4 days to collect half the array and it was with some relief that we trundled back into base camp having had no encounter with armed men.  A hot shower, something other than sardines to eat and the excitement of examining the camera-trap pictures was a just reward for all our foot work

The cameras were being used to assess what species were present in the park and as such were left up for short periods in small arrays. In the Serengeti however, there are 225 camera traps permanently running in an area of 1125 km2. Just think of the logistics involved with changing batteries, keeping vegetation trimmed back and changing SD cards. Our researchers work tirelessly to keep the project on its toes and over the next few months I will try to bring you their stories about the work we support from the comfort of our homes. We each have our part to play but together we are a team dedicated to furthering a scientific cause.

 

Why we do it

Congratulations, your time classifying images on Snapshot Serengeti has resulted in yet another scientific paper. Over 70,000 of you have contributed to analysing the millions of images produced by the 225 Snapshot Serengeti cameras over the last few years. Thanks to all your effort the cameras are still rolling, creating one of the longest running cameratrap studies going.  This data set is so important to scientists because of the size of the area it covers as well as the length of time it has been recording for. It allows them to ask many and varied questions about a naturally functioning healthy ecosystem and in today’s changing world it has never been so important to figure out what makes this planet tick.

The paper ‘The spatial distribution of African Savannah herbivores: species associations and habitat occupancy in a landscape context’ was published last year in Philosophical Transactions B. Visit here to read the article.

http://rstb.royalsocietypublishing.org/content/371/1703/20150314

The Snapshot Serengeti team argue that if we want to predict the impact of changes/ losses of large mammals in the future we need to have a quantitative understanding of a currently functioning ecosystem. It just so happens that the Snapshot data set is perfect for this. The Serengeti National Park is representative of the grass dominated Savannahs of East Africa which are home to the world’s greatest diversity of ungulate (hoofed animals) grazers.

The team present a neat graphic that shows how the various elements interact to affect herbivore habitat occupancy.

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Predators, herbivores, termites, fire, grasses and trees all play a role in determining where different herbivores choose to roam.

It seems that herbivore body size is also important to habitat selection. For example large herbivores survive by bulk grazing whereas small herbivores concentrate on grazing quality over quantity. Recently burned ground results in new vegetation growth. This growth is relatively high in nutrients compared with unburned patches and the same can be found on and around termite mounds. Small herbivores were found to occupy these areas but the sparse coverage does not favour large herbivores that must eat more volume.

The paper highlights the complex relationship between predators, herbivores, vegetation and disturbance and is well worth a read. Next time you are classifying images see if you agree. Do you see many herds of zebra or wildebeest on burnt areas or is it mostly Thompson’s gazelle? It’s another way to look at the images you classify.

Serengeti Science-ing!

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We’re thrilled to announce another scientific paper from the Snapshot Serengeti team! This is one that has been a long time in the coming. It’s the revised third chapter of my dissertation, so you’ve heard me blog about these ideas time and time again. What’s especially exciting is that after several years of publishing methodological research about how camera traps and citizen science works, we’re finally turning your classifications into real ecological research, answering the fundamental questions about how species coexist.

“In the absence of a landscape of fear” has just been published in the Journal of Ecology and Evolution: you can check it out here. It’s an open access journal, which means you don’t need an academic library account to see the paper.

The short of the long is that we used camera traps to study how lions, hyenas, and cheetahs divided up the landscape in very fine scales. Our research before Snapshot Serengeti had indicated that lions exclude wild dogs from large areas of the landscape, so they lose out on access to the resources in these large areas and their populations suffer. Surprisingly, we found that cheetahs weren’t excluded from large areas nor did their numbers suffer in the same way.

We had suspected that this was because cheetahs were able to avoid lions on a moment-to-moment basis, but it was only with the camera trap data from Snapshot Serengeti that we’ve finally been able to test that!

Using Snapshot Serengeti data, we found that cheetahs actually show up more often in areas with more lions. This is probably because cameras reflect really desirable real estate — nice shady trees that attract prey and are near water sources. Instead of always avoiding those habitat hotspots because they have lots of lions (and lions are dangerous), cheetahs appear to just avoid those areas in the 12 hours immediately after a lion appears. So this means they’re able to get access to all the resources – shade, water, and prey – but still minimize the risk of actually running into a lion and getting chased or killed.

You can read more about the research here: http://onlinelibrary.wiley.com/doi/10.1002/ece3.2569/full

In other news, I wanted to let you all know that I’m transitioning into a new position through the American Association for the Advancement of Science (AAAS). AAAS administers a big fellowship every year that places scientists into government agencies. I’ll be joining the US Department of State in the Bureau of Oceans, Environment, and Science, to work on international environmental issues. It means I’ll be taking another step away from the academic research, but I hope to stay involved on Snapshot Serengeti in some way. The camera traps are still going strong – now maintained by Meredith and our new collaborators Tom and Michael, and there’s a whole bunch more exciting ecological research in the pipelines.

While we’re busy prepping the next NEXT PHASE of the Snapshot project (details coming soon!), we’ll be having guest posts from some of our invaluable undergraduate volunteers here in the University of Minnesota Lion Lab. They are writing a series on some of the lesser-known small animals which inhabit the Serengeti Park. Today, Lexi Vogler shares some information about the minuscule Klipspringer antelope: 

The Klipspringer, or Oreotragus oreotragus, is a small antelope that lives on cliffs and rock outcrops in mid-eastern and southern Africa. This mammal weighs up to 18kg and can reach a height of 60cm. It stands on the tips of its hooves, which are adapted for steep and rocky terrains (such as kopjes). In this type of terrain and with their climbing and jumping abilities, the klipspringer can stray away from predators and can obtain an adequate food supply. These animals stand on the ends of their hooves, so they can easily stand with all four hooves close together, easily adapting to the rocky landscape.

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https://en.wikipedia.org/wiki/Klipspringer

Klipspringers have a specially insulated coat that can withstand freezing or extremely hot temperatures. They are extremely adaptable animals, including within their diet. They will feed on the vegetation that grows in between rocks in a kopje, as well as on leaves, shoots, succulents, berries, fruits, seedpods, and green grass. Klipspringers can typically obtain most of their moisture need through their food. They will travel up to 0.5km away from their shelter to forage for food during the dry season.

Socially, the klipspringer typically stays with one mate, and they share a permanent home or territory. They care and guard their offspring together, but it is rare to see two klipspringers make contact with one another. Instead, klipspringers will communicate through scent, sound and sight.  They typically move and feed during the nighttime, and will lie in the shade in the afternoon when it starts to become hot.

Stay tuned to discover more interesting facts about these creatures and share in the comments if there are any animals you are particularly curious and would like to know more about! 

The Secret Life of Trees

This is another guest post by Drs. Tom Morrison and Michael Anderson  about the Snapshot Serengeti Special Edition and what their research hopes to uncover.

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Seeing the forest for the trees

First, a big THANK YOU to everyone who has helped classified images at Snapshot Serengeti, both past and present. Without the continued help of this great online community, our research would come to a grinding halt! So thank you. A number of folks (and at least one giraffe) have asked about the new study currently up on Snapshot Serengeti, so here’s a fuller explanation of this work.

Photos from our newest Snapshot Serengeti Special Season come from a camera trap experiment in Serengeti involving friends and collaborators based at Wake Forest University (US), University of Georgia (US) and University of Glasgow (UK).

One of the exciting things about these new images is that they come from some of the more remote corners of the park, far beyond where past photos (Season 1-9) were (and continue to be) collected. So, keep an eye out for different species than past surveys. For instance in the north, you might see oribi, a small and elegant ungulate with a large dark scent gland below its eye. In the south, our cameras overlap the home ranges of some of the few black rhinoceros still living in the park, and we already know there are at least a few rhino images in our pile, like this:

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We set these cameras at a slightly higher height (1.5 meters in most cases), which allows us to see species from new wider angles. Admittedly, this new experimental design makes animal classifications a bit harder because we can often see far into the distance. Our advice is to simply do your best, but don’t sweat it too much if you can’t figure it out. Better to see the forest than the trees.

Back to the research…

Speaking of trees, this new study is trying to unravel the secret lives of trees. We monitor hundreds of individually marked trees around the ecosystem and revisit them each year to measure growth, survival, disease and few other things. You may have noticed little cages in some of the camera trap photos (see giraffe above). These are part of our experiment and enclose four small native tree seedlings which we transplanted to the plots after growing them in a nursery for 6 weeks. In fact we planted over 800 seedlings around the ecosystem to study the relative importance of herbivory, fire and rainfall on seedling growth and survival. So, we need camera traps to monitor things when we’re not there.

For example, check out the following sequence captured on one of our game cameras in southern Serengeti involving one of our marked trees:

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What’s amazing about this is that not only does an elephant kill an adult tree, he does it under 60 seconds. This tree is an Acacia tortilis, or the “umbrella acacia,” named for its characteristic flat top. Umbrella acacias are one of the most common trees in Serengeti and one of our main study species. Images like these help inform our study of trees, telling us how they died, or at least how many large herbivores were in the area to potentially kill and eat them. But this begs the question: if a tree falls in the Serengeti, will anyone hear it? At least we know that there’s a small chance that one of our cameras might see it.

Just where are we, anyway?

If you’ve been clicking through our new “extended survey” season, you might have noticed some new critters — particularly lots of cattle, sheep, goats, even donkeys! This is because the extended survey reaches much farther north, west, south, and east than the long-term camera study area. You can see all of Tom’s and Michael’s cameras on the map below in the black and gray circles. Two sites are at the edge of the park, where we might expect to see  the occasional pastoralist passing by  (even if they’re not supposed to) — and one site is *all* the way down deep in the Ngorongoro Conservation Area, where pastoralists live permanently.  If you see any livestock in the images, go ahead and mark them as “cattle” — we’ll be able to figure it out from there!

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A Snapshot Serengeti Special Edition!

Join us for a special edition of Snapshot Serengeti! Hot on the heels of Season 9, we’re launching the Snapshot Serengeti Extended Survey – a season loaded with photos from new locations in the Serengeti Ecosystem.

The original Snapshot Serengeti team has joined up with Prof. Michael Anderson (from Wake Forest University), Prof. Rico Holdo (from University of Georgia) and Dr. Tom Morrison (from University of Glasgow, UK) to understand how wildebeest, zebra and other herbivores impact vegetation dynamics in Serengeti.

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Michael measuring soil moisture at a vegetation plot

We are particularly interested in understanding how the many many herbivores in Serengeti (both in terms of total number and the diversity of species) impact the growth, survival and germination of savanna trees. But why study trees? Savannas – like the one found throughout the Serengeti – present a bit of a paradox for ecologists. Most savannas receive sufficient rainfall throughout the year that they “should” become forests. We know that things like fire and herbivory help them maintain a mixture of continuous grasslands interspersed with smaller number of trees. Indeed, Serengeti receives enough rainfall (450mm per year at the driest part of the ecosystem to over 1000mm in the wettest) that it should be chocked full of trees, but yet, for most of the ecosystem, it remains a savanna (and quite a beautiful one).

We’ve designed an experiment understand the fate (the life and death and growth) of small trees at the seedling and sapling stage. During the wet season, we germinated a large number of seedlings in a nursery at the research center in Serengeti (see photo). We selected the two most dominant trees in the ecosystem: Acacia tortilis (commonly known as the umbrella acacia) and Acacia robusta (the stink bark acacia).

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Seedlings in the nursery

After growing 760 seedlings for about 6-8 weeks in the nursery, we transplanted them in the field at 19 different plots across the ecosystem, spanning the large gradient in rainfall mentioned above. Once in the ground, we subject them to various treatments (or mistreatments, if you like) such as fire, herbivory and watering. By using a combination of these different treatments, we hope to understand how important they are in determining the survival of trees at a small stage, which will ultimately inform why they survival into adulthood.

Our camera traps are set up at all of these different plots so we can track how herbivores use these areas differently and the effect that has on the vegetation, and we need your help to classify the photos! So head on over to Snapshot Serengeti  and dive in! You never know what you might find!

 

Hot off the presses – get your “good data” right here!

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It’s finally out! 9 long months ago, we received the good news that our second Snapshot Serengeti paper was accepted for publication in Conservation Biology as part of a special section on citizen science. Patience has never been my strong suit, so I’m overjoyed to announce that that special section is finally published!

The paper takes a pretty detailed look at how we turn your answers into our final dataset (that same one that was published in Nature Scientific Data last June). Remember that you guys are good, and even when you’re not sure about what you’re seeing, those wrong answers help us determine just how difficult an image is. My favourite demonstration of this is the boxplot below:

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Now, I’ve written about this guy (and how to read boxplots) before. The gist of it is that we calculate a measure of disagreement across all of your answers for a given image. The disagreement score (also called evenness) ranges from 0 to 1, with 0 meaning that everyone agreed on what they saw and 1 meaning everyone said something different. You can see from the histogram on the right side of the plot that the vast majority of images were easy: everyone said the same thing! A good number of images are easy-ish, and a very small portion of the images are hard, with high disagreement scores.

When we compare images to experts, and look a the disagreement scores for images that were identified correctly or incorrectly, we see that images that were correct have generally lower disagreement scores (box on the left) than those that were incorrect (box on the right). That means we can use the disagreement score to predict whether images are probably right or wrong. If an image has a high disagreement score, it’s probably wrong or impossible, and we might want to have an expert review it before using it in an analysis.

For example. Across all images with disagreement scores 0-1, we know that 97% of images are correct. But say we want higher accuracy, so we set a threshold of images we accept and target for review. For example, 98.2% of images with a disagreement score of <0.75 are correct, so we could just accept all the ones with scores <0.75 and target all images >0.75 for review. Looking at the histogram to the right, that’s a pretty small percent of images needing a second look.SSblogslides.017

If 98.2% isn’t good enough, we can make that threshold stricter.

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99.7% of images with disagreement scores <0.5 are correct, so we could set that as our threshold, and conduct an expert review of all images with scores above that. It’s still a relatively small number of images we need to look at.

Anyway. I know I’ve written about this before, but I think this really gets at the heart of why the Zooniverse/Snapshot Serengeti approach works for producing useable scientific data. And why your answers, even when you’re not confident in them, are so incredibly valuable. This approach means that ecologists and conservation biologists can engage volunteers like you on other camera trapping projects to tackle their own enormous camera trap datasets – enabling us to do bigger, broader research much faster.

You can check out the paper for more details on this analysis, and more! It’s an open access publication, so you can access it, for free, even without needing a University library account.

As always, this wouldn’t be possible without your help. So thank you, again, for time and your clicks. And I can’t wait to see what you help us discover next!

 

Pre-Dawn in Serengeti

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There are definitely pros to early-morning fieldwork! Heading out to do camera trap experiments often required hitting the road before sun-up, and with the right composition of clouds, you often got to experience beautiful sunrises. Here, you can see the front of my LandRover as we’re about to tackle this swampy stretch of road!