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

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 18th 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?

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?

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

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

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?

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.

©Arpat Ozgul, University of Zurich

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

Using Experimental Methodology to Determine Grassland Response to Climate Change

Post provided by Heather Hager

©Hajnal Kovacs

In the second chapter of Grasslands and Climate ChangeMethodology I: Detecting and predicting grassland changeJonathan Newman and I take an in-depth look at the experimental methodology that has been used to determine how grassland ecosystems will respond to climate change. When we set out, we were interested in knowing, for example, the magnitudes and types of treatments applied, plot sizes, replication, study durations, and types of response variables that were measured and by how many studies. For simplicity(!), we focused on three treatment types: changes in atmospheric carbon dioxide levels, changes in temperature (mean, minimum, maximum), and changes in precipitation (increases, decreases, timing).

Using the methods of a formal systematic review, we identified 841 relevant studies, for which we extracted information on study location and experimental methodology. There were some surprises, both good and bad. For instance, mean and median plot sizes were actually larger than we had expected. On the other hand, numbers of true experimental replicates were low. Although many of the study methods were well reported, some areas lacked critical detail such as descriptions of (at least) the dominant plant species in the study area.

Continue reading

New Technologies Could Help Conservationists Keep Better Track of Serengeti Wildebeest Herds

Below is a press release about the Methods in Ecology and Evolution article ‘A comparison of deep learning and citizen science techniques for counting wildlife in aerial survey images‘ taken from the University of Glasgow.

A wildebeest herd in the Serengeti. ©Daniel Rosengren

A wildebeest herd in the Serengeti. ©Daniel Rosengren

Mathematicians and conservationists from the UK, Africa and the United States have used machine-learning and citizen science techniques to accurately count wildebeest in the Serengeti National Park in Tanzania more rapidly than is possible using traditional methods.

Evaluating wildebeest abundance is currently extremely costly and time-intensive, requiring manual counts of animals in thousands of aerial photographs of their habitats. From those counts, which can take months to complete, wildlife researchers use statistical estimates to determine the size of the population. Detecting changes in the population helps wildlife managers make more informed decisions about how best to keep herds healthy and sustainable. Continue reading

‘Eavesdropping’ Technology used to Protect one of New Zealand’s Rarest Birds

Below is a press release about the Methods in Ecology and Evolution article ‘A novel method for using ecoacoustics to monitor post‐translocation behaviour in an endangered passerine‘ taken from the Zoological Society of London.

Juvenile hihi. ©ZSL

Juvenile hihi. ©ZSL

Scientists from international conservation charity ZSL (Zoological Society of London), Imperial College London and conservationists from the Rotokare Scenic Reserve Trust used acoustic monitoring devices to listen in on the ‘conversations’ of New Zealand’s endemic hihi bird, allowing them to assess the success of the reintroduction without impacting the group.

For the first time ZSL scientists were able to use the calls of a species as a proxy for their movement. A happy hihi call sounds like two marbles clanging together in what is known as the ‘stitch’ call. Scientists saw the calls change from an initial random distribution to a more settled home range – marking the hihi reintroduction and the new method a success. Continue reading

Map of Chemicals in Jellyfish Could be the Future to Protecting UK Waters and Marine Life

Below is a press release about the Methods in Ecology and Evolution article ‘Spatial models of carbon, nitrogen and sulphur stable isotope distributions (isoscapes) across a shelf sea: An INLA approach‘ taken from the University of Southampton.

Jellyfish opportunistically caught in UK waters are used to map chemical variations across marine space. ©University of Southampton

Jellyfish opportunistically caught in UK waters are used to map chemical variations across marine space. ©University of Southampton

Scientists at the University of Southampton have developed maps of chemicals found in jellyfish which could offer a new tool for conservation in British waters and fisheries. The maps will also be able to detect fraudulently labelled food in retail outlets by helping to trace the origins of seafood.

The Southampton based research team including Dr Clive Trueman, Dr Katie St. John Glew and Dr Laura Graham, built maps of the chemical variations in jellyfish caught in an area of approximately 1 million km2 of the UK shelf seas. These chemical signals vary according to where the fish has been feeding due to differences in the marine environment’s chemistry, biology and physical processes. Continue reading