Remote Sensing for Counting Animals: Polar Bears, Sheep and Everything In-Between

Post provided by Tracey Hollings

In an age of rapid technological advances, ecologists need to keep abreast of how we can improve or reinvent the way we do things. Remote sensing technology and image analysis have been developing rapidly and have the potential to revolutionise how we count and estimate animal populations.

Using remotely sensed imagery isn’t new in ecology, but recent innovations mean we can use it for more things. Land use change and vegetation mapping are among the areas of ecology where remote sensing has been used extensively for some time. Estimating animal populations with remotely sensed imagery was also demonstrated more than 40 years ago by detecting indirect signs of an animal with some success: think wombat burrows and penguin poop.

A polar bear from a helicopter

A polar bear from a helicopter

Thanks to improved spatial and spectral resolution (see the text box at the bottom of the post for a definition), accessibility, cost and coverage of remotely sensed data, and software development we have now reached a point where we can detect and count individual animals in imagery. Many of the first studies to demonstrate automated and semi-automated techniques have taken computer algorithms from other disciplines, such as engineering or biomedical sciences, and applied them to automate counting of animals in remotely sensed imagery. It turns out that detecting submarines is not so different to detecting whales! And finding abnormal cells in medical imaging is surprisingly similar to locating polar bears in the arctic! Continue reading


New Associate Editor: Chris Sutherland

Today, we are pleased to welcome the latest new member of the Methods in Ecology and Evolution Associate Editor Board. Chris Sutherland joins us from the University of Massachusetts, USA and you can find out a little more about him below.

Chris Sutherland

“I’m an applied ecologist with a focus on spatial population ecology. I am particularly interested in understanding how spatial processes such as movement, dispersal and connectivity, influence the dynamics of spatially structured populations. Most of my research involves the development and application of spatially realistic hierarchical models for observations of individuals, populations and metapopulations.”

Chris has had a couple of articles published in Methods in Ecology and Evolution in recent years. In his 2015 article ‘Modelling non-Euclidean movement and landscape connectivity in highly structured ecological networks‘ Chris and his co-authors (Angela K. Fuller and J. Andrew Royle) evaluated the consequences of not accounting for movement heterogeneity when estimating abundance in highly structured landscapes, and demonstrated the value of this approach for estimating biologically realistic space-use patterns and landscape connectivity.

A multiregion community model for inference about geographic variation in species richness‘ by Chris, Mattia Brambilla, Paolo Pedrini and Simone Tenan was published in the journal in 2016. This paper reported on a new approach that provided a mechanism for testing hypotheses about why and how species richness varies across space.

Last year, Chris was also involved in ‘Quantifying spatial variation in the size and structure of ecologically stratified communities‘, which was published in the August issue of Methods. In this article, the authors provided a novel hierarchical multi-region community model for direct modelling of trait-based patterns of species richness along environmental gradients by splitting communities into ecologically relevant strata.

Chris currently has a number of ongoing projects including a long term (20 year) metapopulation study on water voles in North West Scotland with the objectives of better understanding the spatial drivers of colonisation-extinction dynamics and persistence of spatially structured populations. He is also working on monitoring and density estimation of a recovering population of American marten using photographic capture-recapture using a novel camera trapping design.

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

How Can We Quantify the Strength of Migratory Connectivity?

Technological advancements in the past 20 years or so have spurred rapid growth in the study of migratory connectivity (the linkage of individuals and populations between seasons of the annual cycle). A new article in Methods in Ecology and Evolution provides methods to help make quantitative comparisons of migratory connectivity across studies, data types, and taxa to better understand the causes and consequences of the seasonal distributions of populations.

In a new video, Emily Cohen, Jeffrey Hostetler and Michael Hallworth explain what migratory connectivity is and how the methods in their new article – ‘Quantifying the strength of migratory connectivity‘ – can help you to study it. They also introduce and give a quick tutorial on their new R package MigConnectivity.

This video is based on the article ‘Quantifying the strength of migratory connectivity by Cohen et al.

Sticking Together or Drifting Apart? Quantifying the Strength of Migratory Connectivity

Post provided by Emily Cohen

Red Knot migratory connectivity is studied with tracking technologies and color band resighting. © Tim Romano

Red Knot migratory connectivity is studied with tracking technologies and colour band resighting. © Tim Romano

The seasonal long-distance migration of all kinds of animals – from whales to dragonflies to amphibians to birds – is as astonishing a feat as it is mysterious and this is an especially exciting time to study migratory animals. In the past 20 years, rapidly advancing technologies  – from tracking devices, to stable isotopes in tissues, to genomics and analytical techniques for the analysis of ring re-encounter databases – mean that it’s now possible to follow many animals throughout the year and solve many of the mysteries of migration.

What is Migratory Connectivity?

One of the many important things we’re now able to measure is migratory connectivity, the connections of migratory individuals and populations between seasons. There are really two components of migratory connectivity:

  1. Linking the geography of where individuals and populations occur between seasons.
  2. The extent, or strength, of co-occurrence of individuals and populations between seasons.

Continue reading

Issue 8.11

Issue 8.11 is now online!

The November issue of Methods is now online!

This extra large issue contains seven Applications articles and three Open Access articles. These five papers are freely available to everyone, no subscription required.

 LSCorridors: LandScape Corridors considers stochastic variation, species perception and landscape influence on organisms in the design of ecological corridors. It lets you simulate corridors for species with different requirements and considers that species perceive the surrounding landscape in different ways.

 HistMapR: HistMapR contains a number of functions that can be used to semi-automatically digitize historical land use according to a map’s colours. Digitization is fast, and agreement with manually digitized maps of around 80–90% meets common targets for image classification. This manuscript has a companion video and was recommended by Associate Editor Sarah Goslee.

 vortexR: An R package to automate the analysis and visualisation of outputs from the population viability modelling software Vortex. vortexR facilitates collating Vortex output files, data visualisation and basic analyses (e.g. pairwise comparisons of scenarios), as well as providing more advanced statistics.

Continue reading

Issue 8.8

Issue 8.8 is now online!

The August issue of Methods is now online!

This issue contains two Applications articles and two Open Access articles. These four papers are freely available to everyone, no subscription required.

 Paco: An R package that assesses the phylogenetic congruence, or evolutionary dependence, of two groups of interacting species using both ecological interaction networks and their phylogenetic history.

 Open MEE: Open Meta-analyst for Ecology and Evolution (Open MEE) addresses the need for advanced, easy-to-use software for meta-analysis and meta-regression.It offers a suite of advanced meta-analysis and meta-regression methods for synthesizing continuous and categorical data, including meta-regression with multiple covariates and their interactions, phylogenetic analyses, and simple missing data imputation.

Continue reading

Tiny Grains, Big Data: The Global Pollen Project

Post Provided by Andrew Martin

A drawer from the Oxford Long-Term Ecology Lab (OxLEL) pollen reference collections, which has been digitised into the Global Pollen Project reference set.

A drawer from the Oxford Long-Term Ecology Lab (OxLEL) pollen reference collections, which has been digitised into the Global Pollen Project reference set.

The Global Pollen Project is a new, online, freely available tool developed to help people identify and disseminate palynological resources. Palynology – the study of pollen grains and other spores – is used across many fields of study modern and fossil vegetation dynamics, forensic sciences, pollination, beekeeping, and much more. This platform helps to facilitate cross/multi-disciplinary integration and discussion, outsourcing identifications, expertise and the sharing of knowledge.

Pollen’s Role in Plant Conservation

Successful conservation of rare, threatened, and valuable plants is dependent on an understanding of the threats that they face. Also, conservationists must prioritise species and populations based on their value to humans, which may be cultural, economic, medicinal, etc. The study of fossil pollen (palaeoecology), deposited through time in sediments from lakes and bogs, can help inform the debate over which species to prioritise: which are native, and when did they arrive? How did humans impact species richness? By establishing such biodiversity baselines, policymakers can make more informed value judgements over which habitats and species to conserve, especially where conservation efforts are weighted in favour of native and/or endemic flora. Continue reading

Estimating the Size of Animal Populations from Camera Trap Surveys

Below is a press release about the Methods paper ‘Distance sampling with camera traps‘ taken from the Max Planck Society.

A Maxwell's duiker photographed using a camera trap. Marie-Lyne Després-Einspenner

A Maxwell’s duiker photographed using a camera trap. ©Marie-Lyne Després-Einspenner

Camera traps are a useful means for researchers to observe the behaviour of animal populations in the wild or to assess biodiversity levels of remote locations like the tropical rain forest. Researchers from the University of St Andrews, the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) and the German Centre for Integrative Biodiversity Research (iDiv) recently extended distance sampling analytical methods to accommodate data from camera traps. This new development allows abundances of multiple species to be estimated from camera trapping data collected over relatively short time intervals – information critical to effective wildlife management and conservation.

Remote motion-sensitive photography, or camera trapping, is revolutionising surveys of wild animal populations. Camera traps are an efficient means of detecting rare species, conducting species inventories and biodiversity assessments, estimating site occupancy, and observing behaviour. If individual animals can be identified from the images obtained, camera trapping data can also be used to estimate animal density and population size – information critical to effective wildlife management and conservation. Continue reading

New Associate Editors

Today we are welcoming four new Associate Editors to Methods in Ecology and Evolution. Graziella Iossa (University of Lincoln) and Theoni Photopoulou (Nelson Mandela Metropolitan University) are joining as regular Associate Editors and Simon Jarman (Unversity of Porto) and Daniele Silvestro (University of Gothenburg) will be working on Applications articles. You can find out more about all of our new Associate Editors below.

Graziella Iossa

“I am an evolutionary ecologist with broad interests in behavioural and population ecology. My research has explored reproductive strategies and the evolution of male and female reproductive traits in mammals and insects and I have used a range of techniques to study the behaviour and welfare of wildlife. I have just started to explore interdisciplinary approaches with the aim to improve our understanding of the value and role of ecosystem services in human health, specifically for antimicrobial resistance.”

Graziella’s most recent paper – Micropyle number is associated with elevated female promiscuity in Lepidoptera – investigates the evolution of the micropyle, a tiny canal which sperm use to fertilise eggs in insects. This is the first study to show that micropylar variation is driven by female promiscuity – the more micropyles her eggs have, the more choice she is likely to have over which male fathers her offspring. Also, Graziella currently holds a NERC Valuing Nature placement which aims to combine perspectives from evolutionary ecology, microbial ecology, epidemiology, ecosystem science and public health to develop a new, holistic way of understanding antimicrobial resistance

Simon Jarman

“Methods employing epigenetics, environmental DNA analysis or bioinformatics for ecological research are improving rapidly and have clear potential for future development. My research focuses on creating new methods in these areas and using them to study population biology and biodiversity. Epigenetic markers for physiological features such as biological age can be used to determine key features of population biology such as age class distribution. Environmental DNA can be used to measure species distributions; biodiversity in environmental samples; and animal diet composition. I am interested in the molecular biology and computational approaches that are required to implement these methods; as well as how they can be used to study specific ecological questions.”

In November 2016, Simon published an Open Access article in Methods in Ecology and Evolution. ‘Optimised scat collection protocols for dietary DNA metabarcoding in vertebrates‘ explains how to collect scat samples to optimise the detection of food DNA in vertebrate scat samples. More recently, Simon was the last author of ‘KrillDB: A de novo transcriptome database for the Antarctic krill (Euphausia superba)‘ – which introduces the most advanced genetic database on Euphausia superba, KrillDB, and includes comprehensive data sets of former and present transcriptome projects.

Theoni Photopoulou

“I am interested in the way biological and ecological phenomena change in space and over time. My special interest is animal movement ecology and the mechanisms behind the patterns of movement we observe. Most of the time I work on ecological questions about how animals use their environment and the resources in it, using data collected remotely with animal-attached instruments. Marine biology was my first love so I will always have a soft spot for marine systems, especially movement of large marine vertebrates, but I work on all sorts of tracking data and also some non-tracking data.”

Theoni has also recently been published in Methods in Ecology and Evolution. Her article ‘Analysis of animal accelerometer data using hidden Markov model‘ appeared in the February issue of the journal (and provided the cover image). In the paper, the authors provide the details necessary to implement and assess a hidden Markov Model in both the supervised and unsupervised learning contexts and discuss the data requirements of each case. Another of Theoni’s articles has just been accepted for publication in Frontiers in Zoology. ‘Evidence for a postreproductive phase in female false killer whales (Pseudorca crassidens)‘ investigates the evidence for postreproductive lifespan (PRLS) in the false killer whale, using a quantitative measure of PRLS and morphological evidence from reproductive tissue.

Daniele Silvestro

“I am a computational biologist and my research focuses on (macro)evolution and the development of new probabilistic models to better understand it. I am interested in the implementation of Bayesian algorithms to model evolutionary processes such as phenotypic trait evolution and species diversification and extinction. I am also interested in historical biogeography and in particular in the estimation of dispersal rates and biotic connectivity between geographic areas. A lot of my work involves developing new models and algorithms and implementing them in computer programs. I have been using both phylogenetic data and fossil occurrences to infer deep time evolutionary dynamics and I am keen to see an improved integration between paleontological and neontological data in evolutionary research.”

In his most recent article – ‘Bayesian estimation of multiple clade competition from fossil data‘ – Daniele and his co-authors explore the properties of the existing Multiple Clade Diversity Dependence implementation, which is based on Bayesian variable selection, and introduce an alternative parameterisation based on the Horseshoe prior. He was also one of the authors of ‘Mammal body size evolution in North America and Europe over 20 Myr: similar trends generated by different processes‘, published in Proceedings of the Royal Society B earlier this year.

We are thrilled to welcome Simon, Graziella, Theoni and Daniele to the Associate Editor Board and we look forward to working with them over the coming years.

Movement Ecology: Stepping into the Mainstream

Post provided by Theoni Photopoulou

“Movement is the glue that ties ecological processes together”
from Francesca Cagnacci et al. 2010

CTD-SRDL telemetry tags being primed for deployment. ©Theoni Photopoulou

CTD-SRDL telemetry tags being primed for deployment. ©Theoni Photopoulou

Movement ecology is a cross-disciplinary field. Its main aim is to quantitatively describe and understand how movement relates to individual and population-level processes for resource acquisition and, ultimately, survival. Today the study of movement ecology hinges on two 21st century advances:

  1. Animal-borne devices/tags (biologging science, Hooker et al., 2007) and/or remote sensing technology to quantify movement and collect data from remote or otherwise challenging environments
  2. Computational power sufficient to manipulate, process and analyse substantial volumes of data

Although datasets often involve small numbers of individuals, each individual can have thousands – sometimes even millions – of data points associated with it. Study species have tended to be large birds and mammals, due to the ease of tag attachment. However, the trend for miniaturisation of tags and the development of remote detection technologies (such as radar, e.g. Capaldi et al., 2000), have allowed researchers to track and study ever smaller animals. Continue reading