Tag Archives: statistics

Stuck between Zero and One: Modelling Non-Count Proportions with Beta and Dirichlet Regression

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Post provided by JAMES WEEDON & BOB DOUMA

Chinese translation provided by Zishen Wang

這篇博客文章也有中文版

Proportion of leaf damage is a type of measurement that can lead to proportional data.

Imagine the scene: you’re presenting your exciting research results at an important international conference. Being conscientious and aware of statistical best-practice and so you’ve included test statistics and confidence intervals on all your result figures. Not just P values! Some of the data you are presenting involves the proportion of leaf surface damaged by an insect herbivore under different treatments. You finish your presentation (on time!) and there’s time for questions. From the audience a polite but insistent colleague asks: “Your confidence interval for that estimate goes from -0.3 to 0.5… how should we interpret a negative proportion of a leaf?”.

Someone chuckles. As you nervously flick back to the slide in question, you mutter something about the difference between confidence intervals and point estimates. You start to feel dizzy. A murmur of confused voices slowly builds amongst the audience members. In the distance, a dog barks.

How can you avoid this?

Proportional Data in Ecology and Evolution

Many kinds of quantities that ecologists and evolutionary biologists routinely measure are most conveniently expressed as proportions. In many cases these proportions are derived from counts. The data are based on discrete entities that can be assigned to two or more classes: success or failure, male or female, invasive or non-invasive. In other cases the proportions are derived from continuous measurements: the proportion of time an animal spends on different activities;  percent cover of a plant functional type in a vegetation survey quadrat; allocation of total plant biomass to different organs and tissues. What these data types have in common is that they can only take values between zero and one. Negative values, or values greater than one, don’t make any sense. Continue reading →

New Associate Editor: Res Altwegg

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Today, we are pleased to be welcoming a new member of the Methods in Ecology and Evolution Associate Editor Board. Res Altwegg joins us from the University of Cape Town, South Africa and you can find out a little more about him below.

Res Altwegg

“My interests lie at the intersection between ecology and statistics, particularly in demography, population ecology, species range dynamics and community ecology. My work addresses questions in conservation biology especially in relation to climate change. I’m particularly excited about the increasing availability of large data sets, such as those collected by citizen scientists, and the opportunities and challenges their analysis brings.”

Res is the founding director of the centre for Statistics in Ecology, Environment and Conservation at the University of Cape Town. The centre brings together ecologists and statisticians with the aim to address some of the most important questions in ecology and conservation using cutting-edge statistical methods. He has reviewed for Methods in Ecology and Evolution a number of times over the past few years and has had one article – ‘A general framework for animal density estimation from acoustic detections across a fixed microphone array‘ – published in the journal. Another of Res’ articles has recently been accepted for publication and will appear in an upcoming Special Feature.

We are thrilled to welcome Res as a new Associate Editor and we look forward to working with him on the journal.

R2ucare: An Interview with Olivier Gimenez

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At the International Statistical Ecology Conference in St Andrews this July (ISEC 2018) David Warton interviewed Olivier Gimenez about R2ucare. R2ucare is an R package for goodness-of-fit tests for capture-recapture models. The full Methods in Ecology and Evolution article on this package – R2ucare: An r package to perform goodness‐of‐fit tests for capture–recapture models – was published in the July 2018 issue of the journal.

David and Olivier also discuss some tips for creating R packages. They mention that if you’re new to writing R packages, there are some excellent resources online. Here’s one of them: A Quickstart Guide for Building Your First R Package

We’ll have more of David’s interviews from the ISEC coming out over the next few weeks. Keep an eye out for them here and on the Methods in Ecology and Evolution YouTube channel.

You can find David’s first ISEC interview (with Kate Jones) here.

Crossing the Palaeontological-Ecological Gap

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Today is the first day of the Crossing the Palaeontological-Ecological Gap (CPEG) conference. The aim of the conference is to open a dialogue between palaeontologists and ecologists who work on similar questions but across vastly different timescales. This splitting of temporal scales tends to make communication, data integration and synthesis in ecology harder. A lot of this comes from the fact that palaeontologists and ecologists tend to publish in different journals and attend different meetings.

Methods in Ecology and Evolution is one of few ecological journals that attracts submissions from both ecologists and palaeontologists. To highlight this, we’ve released a Virtual Issue, also called Crossing the Palaeontological-Ecological Gap. Continue reading →

Bats, Acoustic Methods and Conservation 4.0: An Interview with Kate Jones

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At this year’s International Statistical Ecology Conference (ISEC 2018) David Warton interviewed Kate Jones, Chair in Ecology and Biodiversity at University College, London. Their conversation mainly focused on how to classify bats from acoustic data, with particular reference to ‘Acoustic identification of Mexican bats based on taxonomic and ecological constraints on call design‘ by Veronica Zamora‐Gutierrez et al. They also discuss Conservation 4.0!

We’ll have more of David’s interviews from the ISEC coming out over the next few weeks. Keep an eye out for them here and on the Methods in Ecology and Evolution YouTube channel.

An Interview with Tony Ives

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David Warton interviews Tony Ives, a Keynote speaker at the Statistics in Ecology and Environmental Monitoring (SEEM) conference in Queenstown, NZ. Tony has published a few papers in Methods in Ecology and Evolution over the last couple of years – first we discuss the exchanges on log-transformation of counts (including a paper co-authored with David Warton).

Tony and David then talk about a recent paper by Daijiang Li with Tony, on the need to check for phylogenetic structure when looking for associations between species trait and the environment.

We’ll have more of David’s interviews from the SEEM Conference coming out over the next couple of months. Keep an eye out for them here and on the Methods in Ecology and Evolution YouTube channel.

Methods in Ecology and Evolution 2017: The Year in Review

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Happy New Year! We hope that you all had a wonderful Winter Break and that you’re ready to start 2018. We’re beginning the year with a look back at some of our highlights of 2017. Here’s how last year looked at Methods in Ecology and Evolution.

The Articles

We published some amazing articles in 2017, too many to mention them all here. However, we would like to take a moment to thank all of the Authors, Reviewers and Editors who contributed to the journal last year. Your time and effort make the journal what it is and we are incredibly grateful. THANK YOU for all of your hard work!

Technological Advances at the Interface between Ecology and Statistics

Our first Special Feature of the year came in the April issue of the journal. The idea for Technological Advances at the Interface between Ecology and Statistics  came from the 2015 Eco-Stats Symposium at the University of New South Wales and the feature was guest edited by Associate Editor David Warton. It consists of five articles based on talks from that conference and shows how interdisciplinary collaboration help to solve problems around estimating biodiversity and how it changes over space and time.

Continue reading →

Learn to be a Reviewer: Peer Reviewer Mentoring Scheme

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Today is the first day of peer review week. One of the issues that many people bring up about the current system of peer review is that there is very little formal training. There are guidance documents available (including the BES Guide to Peer Review), workshops on peer review can be found at some conferences and some senior academics teach their PhD students or post-docs about the process. In general though, peer review training is fairly hard to come by.

This is something that people have told us (the BES publications team) at conferences and through surveys, so we’re doing something about it. From October 2017 until April 2018 Methods in Ecology and Evolution is going to be partnering with the BES Quantitative Ecology Special Interest Group to run a trial Peer Review Mentoring Scheme.

The trial scheme is going to focus on statistical ecology (as we receive a lot of statistical papers at Methods in Ecology and Evolution), but if it goes well, we’ll be looking at other areas of expertise too.

Applications for Mentor and Mentee positions are now open. If you’re an experienced statistical ecologist or evolutionary biologist or an Early Career Researcher in those fields, we’d love to receive an application from you. Continue reading →

Bottom-up Citizen Science and Biodiversity Statistics

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Post provided by Ditch Townsend and Robert Colwell

Different Paths to Science

Ditch Townsend on Exmoor in Devon, UK

Ditch Townsend on Exmoor in Devon, UK

DITCH: Amateur naturalists from the UK have a distinguished pedigree, from Henry Walter Bates and Marianne North, to Alfred Russel Wallace and Mary Anning. But arguably, the rise of post-war academia in the fifties displaced them from mainstream scientific discourse and discovery. Recently, there has been a resurgence of the ‘citizen scientist’, like me, in the UK and elsewhere – although the term may refer to more than one kind of beast.

To me, the ‘citizen scientist’ label feels a little patronising – conveying an image of people co-opted en masse for top-down, scientist-led, large-scale biological surveys. That said, scientist-led surveys can offer valid contributions to conservation and the documentation of the effects of climate change (among other objectives). They also engage the public (not least children) in science, although volunteers usually have an interest in natural history and science already. For me though, the real excitement comes in following a bottom-up path: making my own discoveries and approaching scientists for assistance with my projects.

Robert Colwell at the Boreas Pass in Colorado, USA

Robert Colwell at the Boreas Pass in Colorado, USA

ROB: I grew up on a working ranch in the Colorado mountains, surrounded on three sides by National Forest and a National Wilderness Area. My mother, an ardent amateur naturalist, taught me and my sister the local native flora and fauna and our father instilled a respect for the land in us. For my doctoral research at the University of Michigan, I studied insect biodiversity in Colorado and Costa Rica at several elevations. The challenges of estimating the number of species (species richness) and understanding why some places are species-rich and others species-poor has fascinated me ever since. Continue reading →

At Last, a Paleobiologist is a Senior Editor for Methods in Ecology and Evolution!

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Post provided by Lee Hsiang Liow

An Asian, female Senior Editor under 45? Progressive! I have loved Methods in Ecology and Evolution since it appeared in 2010 and am thrilled to have been selected to join Rob, Bob and Jana to help with the journal’s continued development.

OK, so you want to know who the new Senior Editor on the MEE block is.  I’m just another scientist, I guess. On the outside, we look different but on the inside, we’re all the same. (OK, perhaps we are a little different, even on the inside, but that makes life and research interesting, right?)

Here’s my academic life history: I did my Bachelors thesis on the systematics/phylogenetics of an obscure group of marine pulmonate slugs with one of the greatest Icelandic biologists I know, Jon Sigurdsson, at the National University of Singapore. I followed this up with an almost-half-year stint at the Museum of Natural Science in Berlin as a “nobody”, digitizing data. Then I won the academic lottery and headed up to Uppsala to do my masters in conservation biology on tropical pollinator diversity, (un)supervised by two amazing supervisors that never met each other, the late Navjot Sodhi (National University of Singapore) and Thomas Elmqvist, now at Stockholm University. Continue reading →