Issue 8.2

Issue 8.2 is now online!

The February issue of Methods is now online!

This issue contains four(!) Applications articles and two Open Access articles. These six papers are freely available to everyone – no subscription required.

 Earth Mover’s Distance: The Earth Mover’s Distance (or EMD) is a method commonly used in image retrieval applications. The authors of this paper propose its use to calculate similarity in space use in the framework of movement ecology. This will be helpful for many questions regarding behavioural ecology, wildlife management and conservation.

 warbleR: The R package warbleR is a new package for the analysis of animal acoustic signal structure. It offers functions for downloading avian vocalisations from the open-access online repository Xeno-Canto, displaying the geographic extent of the recordings, manipulating sound files, detecting acoustic signals or importing detected signals from other software, and much more.

– meteR: The open-source R package, meteR directly calculates all of Maximum entropy theory of ecology’s (METE’s) predictions from a variety of data formats; automatically handles approximations and other technical details; and provides high-level plotting and model comparison functions to explore and interrogate models.

– Noise Egg: The Noise Egg is a device that can produce a low-frequency sound, which can be used as an experimental source of noise both in aquaria and in the field. It was developed to study the effects of noise on communication and behaviour in small aquatic animals; however, it could be used for other purposes, such as testing the propagation of certain frequencies in shallow-water habitats.

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Issue 7.10

Issue 7.10 is now online!

The October issue of Methods is now online!

This month’s issue contains three Applications articles and two Open Access articles, all of which are freely available.

– CODYN: New analytical tools applied to long-term data demonstrate that ecological communities are highly dynamic over time. The R package, library(“codyn”), helps ecologists implement these tools and gain insi–ghts into ecological community dynamics.

– Geometric Morphometrics: A tool for the R statistical environment that optimises the smoothing procedure for 3D surfaces used in Geometric Morphometrics.

– TRAPPER: Open source, multi-user software that facilitates analysis of videos and images, provides spatial filtering and web-mapping, allows flexible implementation of specific data collection protocols, and supports data re-use and (re)discovery.

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Stage-dependent Demographic Modelling at Your Finger Tips

Post provided by EELKE JONGEJANS and ROB SALGUERO- GÓMEZ

Soay sheep: an organism that can be modelled with two-sex dynamics. ©Julian Paren

Soay sheep: an organism that can be modelled with two-sex dynamics. ©Julian Paren

Typically, ecology courses contain at least a day of matrix population models. So most ecologists are somewhat familiar with how simple life cycles (and complex ones) can be depicted and analysed using matrix models. Briefly, these models represent what happens to individuals over a certain time interval (do they die? do they reproduce? if so, how much?). What individuals do in the context of these models can then be used to study the dynamics of a population.

Often, individuals are classified by size in matrix models, as small individuals tend to have different survival, growth and reproduction rates than large ones. But how many classes do you need to model the dynamics of a size-structured population properly? Instead of choosing arbitrary size class boundaries, Easterling, Ellner and Dixon (2000) came up with the idea of using continuous size variables and integrals to define a population model… and that’s how the first Integral Projection Model (‘IPM’ for us friends) came to be.

Naturally, for the development of a new demographic tool to prove useful to the scientific community, it must be flexible enough to be ‘one-size-fits-all’… and the needs of ecologists, evolutionary biologists and conservation biologists – who have to date used extensively size-based matrix models – are rather variable in size, colour and shape. Continue reading

Issue 7.2: Demography Beyond the Population

Issue 7.2 is now online!

Sagebrush steppe in eastern Idaho, USA

© Brittany J. Teller

The February issue of Methods is now online! As you may have seen already, it includes the BES cross-journal Special Feature: “Demography Beyond the Population“. There are also eight other wonderful articles to read.

We have four articles in the Demography Beyond the Symposium Special Feature. You can read an overview of them by two of the Feature’s Guest Editor Sean McMahon and Jessica Metcalf here (Sean and Jessica are also Associate Editors of Methods).

If you’d like to find out more about each of the individual papers before downloading them, we have blog posts about each one. Daniel Falster and Rich Fitzjohn discuss the development of plant and provide some advice on creating simulation models in Key Technologies Used to Build the plant Package (and Maybe Soon Some Other Big Simulation Models in R). There is a look back at the evolution of Integral Projection Models from Mark Rees and Steve Ellner in How Did We Get Here From There? A Brief History of Evolving Integral Projection Models. In Inverse Modelling and IPMs: Estimating Processes from Incomplete Information Edgar González explains how you can estimate process that you can’t observe. And keep an eye out for Brittany Teller’s blog post coming next week!

Don’t wait too long to get the Demography Beyond the Population Special Feature papers though, they’re freely available for a limited time only

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Inverse Modelling and IPMs: Estimating Processes from Incomplete Information

Post provided by Edgar J. González

In demography, a set of processes (survival, growth, fecundity, etc.) interacts to produce observable patterns (population size, structure, growth rate, etc.) that change over time. With traditional approaches you follow the individuals of a population over some timespan and track all of these processes.

Demographic patterns and processes (Click to expand)

Demographic patterns and processes (Click to expand)

However, depending on the organism, some processes may be very hard to quantify (e.g. mortality or recruitment in animals or plants with long lifespans). You may have observed the patterns for the organism that you’re studying and, even better, measured some, but not all, of the processes. The question is: can we use this limited information to estimate the processes we couldn’t measure? Continue reading

How Did We Get Here From There? A Brief History of Evolving Integral Projection Models

Post provided by MARK REES and Steve Ellner

The Early Days: Illyrian Thistle and IBMs

Illyrian Thistle

Illyrian Thistle

Back in 1997 MR was awarded a travel grant from CSIRO to visit Andy Sheppard in Canberra. CSIRO had been collecting detailed long-term demographic data on several plant species and Andy was keen to develop data-driven models for management.

Andy decided Illyrian thistle (Onopordum Illyricum) would be a good place to start, as this was the most complicated in terms of its demography. The field study provided information on size, age and seed production. The initial goal was to quantify the impact of seed feeders on plant abundance, but after a few weeks of data analysis it became apparent that the annual seed production per quadrat was huge (in the 1000s) but there were always ~20 or so recruits. This meant that effects of seed feeders (if any) occurred outside the range of the data, which wasn’t ideal for quantitative prediction.

So the project developed in a different direction. Onopordum is a monocarpic perennial (it lives for several years then flowers and dies) and Tom de Jong and Peter Klinkhamer had recently developed models to predict at what size or age monocarps should flower, so it seemed reasonable to see if this would work. Continue reading

Methods Beyond the Population

Post Provided by SEAN MCMAHON and JESSICA METCALF

Demography Beyond the Population” is a unique Special Feature being published across the journals of the British Ecological Society.  The effort evolved from a symposium of the same name hosted in Sheffield, UK last March. Both the meeting and the Special Feature were designed to challenge ecologists from a range of fields whose research focuses on populations.

The participants were charged with sharing how they are pushing the work they do beyond the stage where the population is the focus into research where the population is just the beginning and the focus spans scales, systems and tools. This encompasses a broad suite of biological research, including range modelling, disease impacts on communities, biogeochemistry, evolutionary theory, and conservation biology. The meeting was a great success, and this Special Feature should be equally valuable to the broad readership of the BES journals.

Methods in Ecology and Evolution has a special place in the Special Feature, hosting four papers. These papers not only introduce new efforts in population biology, they provide the methods that other scientists can use to implement them. With the tools provided by these four papers, researchers will be able to advance forest modelling, evolutionary theory, climate change biology and statistical inference of hidden population parameters.  Seriously good stuff! Continue reading