Assessing Sea Turtle Populations: Can We Get a Hand From Drones and Deep Learning?

Posted on May 23, 2019 by Chris Grieves

Post provided by PATRICK GRAY

An olive ridley sea turtle in Ostional, Costa Rica. ©Vanessa Bézy.

Understanding animal movement and population size is a challenge for researchers studying any megafauna species. Sea turtles though, add a whole additional level of complexity. These wide-ranging, swift, charismatic animals spend much of their time underwater and in remote places. When trying to track down and count turtles, this obstacle to understanding population size becomes a full-on barricade.

Censusing these animals doesn’t just satisfy our scientific curiosity. It’s critical for understanding the consequences of unsound fishing practices, the benefits of conservation policy, and overall trends in population health for sea turtles, of which, six out of seven species range from vulnerable to critically endangered. Continue reading →

Where do Animals Spend Their Time and Energy? Theory, Simulations and GPS Trackers Can Help Us Find Out

Posted on May 22, 2019 by Chris Grieves

Post provided by MATT MALISHEV (@DARWINANDDAVIS)

An adult sleepy lizard with a GPS tracker and body temperature logger strapped to her tail. ©Mike Bull.

Changes in temperature and available food determine where and when animals move, reproduce, and survive. Our understanding of how environmental change impacts biodiversity and species survival is well-established at the landscape, country and global scales. But, we know less about what could happen at finer space and time scales, such as within habitats, where behavioural responses by animals are crucial for daily survival.

Simulating Movement and Daily Survival with Individual-Based Movement Models

Key questions at these scales are how the states of individuals (things like body temperature and nutritional condition) influence movement decisions in response to habitat change, and how these decisions relate to patchiness in microclimates and food. So we need tools to make reliable forecasts of how fine-scale habitat use will change under future environments. Individual-based movement simulation models are powerful tools for these kinds of studies. They let you construct habitats that vary in temperature and food conditions in both space and time and ask ‘what if’ questions. By populating these models with activity, behaviour, and movement data of animals, we can simulate different habitat conditions and predict how animals will respond to future change. Continue reading →

Early Spring: Predicting Budburst with Genetics

Posted on May 17, 2019 by Chris Grieves

Below is a press release about the Methods in Ecology and Evolution article ‘On the importance of accounting for intraspecific genomic relatedness in multi‐species studies‘ taken from the Université de Montréal.

Bud of American beech (Fagus grandifolia). ©Tim Savas

Researchers from Canada and the USA found that tree and shrub genetics can be used to produce more accurate predictions of when leaves will burst bud in the spring. Their study was published in Methods in Ecology and Evolution.

Although climate sceptics might find it hard to believe with this year’s endless snow and freezing temperatures, climate change is making warm, sunny early springs increasingly common. And that affects when trees start to leaf out. But how much?

Simon Joly, biology professor at Université de Montréal and Elizabeth Wolkovich, an ecology professor at University of British Columbia, showed that a plant’s genetics can be used to produce more accurate predictions of when its leaves will burst bud in spring. Continue reading →

Scant Amounts of DNA Reveal Conservation Clues

Posted on May 9, 2019 by Chris Grieves

Below is a press release about the Methods in Ecology and Evolution article ‘Empowering conservation practice with efficient and economical genotyping from poor quality samples‘ taken from the Stanford Woods Institute for the Environment.

Wild tiger in India. ©Prasenjeet Yadav

The challenges of collecting DNA samples directly from endangered species makes understanding and protecting them harder. A new approach promises cheap, rapid analysis of genetic clues in degraded and left-behind material, such as hair and commercial food products.

The key to solving a mystery is finding the right clues. Wildlife detectives aiming to protect endangered species have long been hobbled by the near impossibility of collecting DNA samples from rare and elusive animals. Continue reading →

Volunteer Ornithological Survey Shows Effects of Temperatures on Eurasian Jay Population

Posted on April 26, 2019 by Chris Grieves

Below is a press release about the Methods in Ecology and Evolution article ‘Incorporating fine‐scale environmental heterogeneity into broad‐extent models‘ taken from the University of Southampton.

A study led by researchers at the University of Southampton has used data collected by volunteer bird watchers to study how the importance of wildlife habitat management depends on changing temperatures for British birds.

The team studied data from the British Trust for Ornithology’s Bird Atlas 2007 – 11 on the abundance of the Eurasian jay over the whole of Great Britain. The University of Southampton researchers focused on jays for this trial as they are a species of bird known to frequent a mixture of different natural environments. Continue reading →

Studying Wild Bats with Small On-Board Sound and Movement Recorders

Posted on April 17, 2019 by Chris Grieves

Post provided by LAURA STIDSHOLT

Releasing a female Greater mouse-eared bat with the tag in collaboration with Holger Goerlitz, Stefan Greif and Yossi Yovel. ©Stefan Greif

The way that bats acrobatically navigate and forage in complete darkness has grasped the interest of scientists since the 18^th century. These seemingly exotic animals make up one in four mammalian species and play important roles in many ecosystems across the globe from rainforests to deserts. Yet, their elusive ways continue to fascinate and frighten people even today. Over the last 200 years, dedicated scientists have worked to uncover how bats hunt and navigate using only their voice and ears while flying at high speed in complete darkness. Still, the inaccessible lifestyle of these small, nocturnal fliers continues to challenge what we know about their activities in the wild.

Understanding the impact bats have on their ecosystems – for example how many insects a bat catches per night – has still not been directly measured. Most of our knowledge on the natural behaviour and foraging ecology is based on elaborate, but ground-based experiments carried out in the wild. These experiments generally track their behaviour using radio-telemetry, record snapshots of their emitted echolocation calls with microphones, or involve extensive observations. Continue reading →

What Biases Could Your Sampling Methods Add to Your Data?

Posted on April 12, 2019 by Chris Grieves

Post provided by ROGER HO LEE

這篇博客文章也有中文版

Have you ever gone fishing? If so, you may have had the experience of not catching any fish, while the person next to you got plenty. If you walked along the pier or bank, you may have seen that other fishermen and -women caught fish of various shapes and sizes. You’d soon realise that each person was using a different set of equipment and baits, and of course, that the anglers differed in their skills and experience. Beneath the water were many fish, but whether you could catch them, or which species could even be caught, all depended on your fishing method, as well as where and how the fish you were targeting lived.

Designing Sampling Protocols

Head view of different ant species found in Hong Kong and further in SE Asia.

Head view of different ant species found in Hong Kong and further in South East Asia.

This is a lot like the situation that ecologists often face when designing sampling protocols for field surveys. While a comprehensive survey will yield the most complete information, few of us have the resources to capture every member of the community we’re studying. So, we take representative samples instead. But the method(s) used for sampling will only allow us to collect a subset of the species which are present. This selection of the species is not random per se – it’s dependent on species’ life history. Continue reading →

採樣方法會帶來怎樣的數據偏差?

Posted on April 12, 2019 by Chris Grieves

作者：李灝

This blog post is also available in English

你有釣魚的經驗嗎？若有的話，以下的經歷對你應該不會陌生。自己釣了大半天，魚杆動也沒動過，但身旁的釣手卻滿載而歸。感到灰心時，你沿著碼頭或岸邊巡視，你看到其他人的魚獲大大小小的也有﹑形態不同的的也有。心裡被疑惑與不甘的思緒纏繞著的一刻，你突然意識到每個人都在使用不同的釣具和魚餌（當然每位垂釣者的技能和經驗也不同）。在水中有各種各樣的魚，但你能否釣到牠們，或者釣到那一些品種，都取決於你釣魚的方法，以及你目標魚種的活動範圍和生活方式。

採樣方案的設計

香港和東南亞地區的螞蟻品種。

上述的經歷與生態學家在設計野外調查時所遇到的情況非常相似。雖然全面的調查能取得最完整的資料，但我們很少會有充足的資源去完整地採集整個物種群落。取而代之的是我們只能採集一部份的物種來作寫照。值得我們留意的是每種採樣方法只允許我們收集到群落中的某些物種；這些物種不是隨機地被選中，而是取決於物種的生活史。 Continue reading →

How Can Understanding Animal Behaviour Help Support Wildlife Conservation?

Posted on April 10, 2019 by Chris Grieves

Below is a press release about the Methods in Ecology and Evolution article ‘A novel biomechanical approach for animal behaviour recognition using accelerometers‘ taken from the EPFL.

Researchers from EPFL and the University of Zurich have developed a model that uses data from sensors worn by meerkats to gain a more detailed picture of how animals behave in the wild.

Advancement in sensor technologies has meant that field biologists are now collecting a growing mass of ever more precise data on animal behaviour. Yet there is currently no standardised method for determining exactly how to interpret these signals. Take meerkats, for instance. A signal that the animal is active could mean that it is moving; alternatively, it could indicate that it is digging in search of its favourite prey, scorpions. Likewise, an immobile meerkat could be resting – or keeping watch.

In an effort to answer these questions, researchers from EPFL’s School of Engineering Laboratory of Movement Analysis and Measurement (LMAM) teamed up with colleagues from the University of Zurich’s Population Ecology Research Group to develop a behavior recognition model. The research was conducted in affiliation with the Kalahari Research Centre. Continue reading →

Phylogenetic Tip Rates: How Well Can We Estimate Diversification?

Posted on March 29, 2019 by Chris Grieves

Post provided by Pascal Title and Dan Rabosky

Analyzing diversification rate heterogeneity across phylogenies allows us to explore all manner of questions, including why Australia has such an incredible diversity of lizards and snakes.

Within the tree of life there are differences in speciation and extinction rates over time and across lineages. Biologists have long been interested in how speciation rates change as a function of ecological opportunity or whether key innovations lead to increases in the rate of speciation. Exploring this rate variation and examining how clades differ in terms of their diversification dynamics can help us to understand why species diversity varies so dramatically in time and space. Learning more about the relationship between traits and diversification rates is especially important because it has the potential to reveal the causes of pervasive variation in species richness among clades and across geographic regions.

Several different classes of methods are available for studying the effects of species traits on lineage diversification rates. These include state-dependent diversification models (e.g., BiSSE, QuaSSE, HiSSE) and several non-model-based approaches. In our article – ‘Tip rates, phylogenies and diversification: What are we estimating, and how good are the estimates?’ – we assessed the accuracy of a number of model-free metrics (the DR statistic, node density metric, inverse of terminal branch lengths) and model-based approaches (Bayesian Analysis of Macroevolutionary Mixtures, BAMM) to determine how they perform under a variety of different types of rate heterogeneity. The “tip rates” using these approaches have become widely used for a few reasons, including ease of computation and how easy it is to pair them with other types of data. Continue reading →

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