Birds and Climate in Space and Time: Separating Spatial and Temporal Effects of Climate Change on Wildlife

Post provided by Cornelia Oedekoven

The Standard Method

When trying to understand how wildlife, for example a bird species, may react to climate change scientists generally study how species numbers vary in relation to climatic or weather variables (e.g. Renwick et al. 2012, Johnston et al. 2013). The way this tends to be done is by gathering information (data!) about bird numbers as well as the weather variables (for example temperature) in several locations (i.e. in space) and fitting a regression model to these data to detect and illustrate how bird numbers go up or down with temperature.

Data on bird numbers and temperatures in several locations lets researchers see the relationship between the two.

Data on bird numbers and temperatures in several locations lets researchers see the relationship between the two.

This relationship is then used to forecast how bird numbers may change along with potential temperature changes in the future (i.e. in time), for example due to climate change.

Relationships between bird numbers and temperature in a given location are often used to forecast changes in bird numbers with expected changes in temperatures over time.

Relationships between bird numbers and temperature in a given location are often used to forecast changes in bird numbers with expected changes in temperatures over time.

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Microphone Backpacks for Individual-level Acoustic Recordings

To understand the factors shaping vocal communication, we need reliable information about the communicating individuals on different levels. First, vocal behaviour should be recorded from undisturbed animals in meaningful settings. Then we have to separate and assign the individuals’ vocalisations. Finally, the precise timing of vocal events needs to be stored.

Microphone backpacks allow researchers to record the vocal behaviour of individual animals in naturalistic settings – even in acoustically challenging environments! In the video below, Lisa Gill, Nico Adreani and Pietro D’Amelio demonstrate the lightweight radio-transmitter microphone backpacks that have been developed and built at the Max Planck Institute for Ornithology, Seewiesen, Department of Behavioural Neurobiology. They show the attachment and setup of this system in detail, evaluate its behavioural effects, and discuss what makes it so useful for studying vocal communication, especially in small animals.

This video is based on the article ‘A minimum-impact, flexible tool to study vocal communication of small animals with precise individual-level resolution‘ by Gill et al.


Biomonitoring Pollution in Wetlands: A New Method for More Reliable Interpretation of Chemical Data

Post provided by Mark Gillingham and Fabrizio Borghesi

Wetlands tend to accumulate considerable anthropogenic pollution.

Wetlands tend to accumulate considerable anthropogenic pollution.

All living organisms are dependent on trace elements (TEs), including metals, that are acquired in very small quantities through their environment or diet. Most TEs are essential for growth, development and physiology of the organism, but excessive intake can be detrimental for animals and plants.  Some TEs – especially heavy metals such as mercury, cadmium, lead and others – are generally toxic though. This toxicity occurs because species’ natural mechanisms fail to excrete excess TEs quickly enough for their metabolism to cope. TEs are present in the environment at different concentrations, either through natural processes or anthropogenic processes (i.e. pollution).

Since the industrial revolution, pollution from human activities has dramatically increased the concentrations of TEs in the natural environment. TEs from pollution tend to persist for a long time on the top layer of soils and sediments, because they do not undergo microbial degradation. As a consequence they tend to enter the food web quicker than the same elements of natural origin.

Some natural environments are more vulnerable to toxic effects of TEs. For instance, wetlands are geochemical endpoints of large river systems that often flow near or through cities, roads, factories, industries, cultivated lands, and/or mines, so they tend to accumulate considerable anthropogenic pollution. Vulnerable habitats like wetlands need to be closely monitored in order to assess the environmental health of these ecosystems. For this kind of monitoring we need reliable methods to measure TEs exposure, intake and bioaccumulation. Continue reading

High-Res Camera Surveys of Wildlife Colonies: The advantages over traditional approaches

Post provided by ALISTAIR HOBDAY (senior principal research scientist, CSIRO Australia), Tim Lynch (senior research scientist, CSIRO, Australia) and Rachael Alderman (wildlife biologist, Tasmanian Department of Primary Industry, Parks, Water and Environment, Australia).

Cameras and wildlife monitoring

A Gigapan camera setup to record images of an albatross colony. ©Alistair Hobday

A Gigapan camera setup to record images of an albatross colony. ©Alistair Hobday

Behavioural and ecological research and monitoring of wildlife populations are based on collection of field data. Demographic data, such as breeding frequency, birth rates and juvenile survival, have been critical in understanding population trends for a wide range of species.

Photography has been extensively used by field biologists and ecologists to gather these data and they have been quick to take up improvements in this technology. Many field programmes today use photography either for primary data collection or the communication of results. Advances in digital photography, image storage and transmission, image processing software and web-based dissemination of images have been extremely rapid in recent years, offering ecologists and biologists a range of powerful tools.

Digital imagery has been captured from a wide range of platforms, each of which has various advantages and limitations for biological study. The most remote images are captured from satellite-based sensors, which have been used to assess population abundance of large animals, such as elephant seals, or locate colonies of emperor penguins. Cameras mounted on aircraft can also provide large-scale perspectives but both of these platforms suffer from high cost, operational limitations due to weather, and limited temporal replication. Recent use of drones, while cheaper, still requires a person to be close to the survey location and can only be used in short bursts, typically lasting less than 20 minutes.

Land-based cameras – or those fixed onto animals – can track behaviour closely, but have low sample size as data tends to be collected at the scale of individual or small groups. To improve replication, fleets of remote cameras can be used or multiple images stitched together post hoc to form a montage. However, this increases cost, either for hardware or labour to manually construct panoramas. To date all these camera systems have had limits to their spatial and/or temporal resolution and, therefore, to the number of individuals covered. This restricts biological study at the population level. Continue reading

Making the Most of Volunteer Data: Counting the birds and more…

Post provided by Rob Robinson

It’s 6am on a warm spring morning and I’m about to visit the second of my Breeding Bird Survey1 sites. Like 2,500 other volunteers in the UK, twice a year I get up early to record all the birds I see or hear on the two transects in my randomly selected 1km square. Each year I look forward to these mornings almost as much for the comparisons as the actual sightings. Will there be more or fewer sightings of our summer migrants this year? How will numbers in this rolling Norfolk farmland stack up against those I see in urban, central Norwich?

Dawn bird survey in arable farmland. © Rob Robinson/BTO

Dawn bird survey in arable farmland. © Rob Robinson/British Trust for Ornithology (BTO)

The importance of demography

But simply recording these changes is not enough; we need to understand why they occur if action is to be taken. This requires us to quantify the demographic rates (survival, productivity and movements) that underlie them, which in turn requires samples of marked individuals. Simply counting individuals is not enough. Continue reading