Latest issue and other articles

A dragonfly

Cover image for issue 3.4 © Dennis Paulson.

Issue 3.4

Our latest issue covers an impressive array of subjects: from metabarcoding (with associated presentation), to population genetics and population monitoring (with video explaining a microphone array system). Modelling and monitoring dispersal also features heavily with four articles, one of which is accompanied by a video for a novel telemetry system to track wild animals. Articles also include topics such as transient dynamics, a review on hormone assay, phylogenetic comparative analysis, stable isotopes (featuring our cover article), plant physiology and finally, statistical methods.

About the cover

Stable-isotope ratios measured in migrating animals have proven to be of great value in understanding migration. For example, when a dragonfly emerges from the water, the isotope signature in that water body is fixed in its wing tissues, which thus provide information about its geographic origin. In A dragonfly (δ2H) isoscape for North America: a new tool for determining natal origins of migratory aquatic emergent insects,  Keith Hobson, David Soto, Dennis Paulson, Leonard Wassenaar and John Matthews compared the isotope value from dragonfly wings of known origin with spatially explicit isoscapes based on water isotopes in precipitation. The relationship was strong, confirming the value of the method to study dragonfly migration.

One of the species used in the analysis was Pachydiplax longipennis. This individual was photographed at Red Slough Wildlife Management Area, Oklahoma. Photo © Dennis Paulson.

Early View articles

Also, these recently accepted articles have appeared on Early View:

Rapid determination of comparative drought tolerance traits: using an osmometer to predict turgor loss point by Megan K. Bartlett, Christine Scoffoni, Rico Ardy, Ya Zhang, Shanwen Sun, Kunfang Cao and Lawren Sack

Free application: taxonstand: An r package for species names standardisation in vegetation databases by Luis Cayuela, Íñigo Granzow-de la Cerda, Fabio S. Albuquerque and Duncan J. Golicher

Projecting species’ range expansion dynamics: sources of systematic biases when scaling up patterns and processes by Greta Bocedi, Guy Pe’er, Risto K. Heikkinen, Yiannis Matsinos and Justin M. J. Travis

Review: Temporal dynamics and network analysis by Benjamin Blonder, Tina W. Wey, Anna Dornhaus, Richard James and Andrew Sih

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Issue 3.3

Rosefinch with geolocator tag

Cover image for issue 3.3
© Germán Garcia – CC Attribution 2.0 Generic

About the issue

Issue 3.3 contains an amazing number of extra features: three videos, one podcast and one Powerpoint presentation. The topics in the issue range from DNA barcoding, surveys, measuring diversity, population and movement modelling and includes five free applications.

About the cover

Recently developed light-weighed tracking devices for positioning through light intensity pattern (‘geolocation’) have begun to greatly improve our knowledge of animal migration. However, the analysis of geolocator data is impeded by many factors potentially affecting light levels and thus, ultimately the determination of positions. Herein, weather and vegetation are major factors altering the light regime experienced by the animals. The picture shows a Common Rosefinch (Carpodactus erythrinus) featured with a 0.5 gram geolocator device.

In Geolocation by light: accuracy and precision affected by environmental factors Simeon Lisovski and colleagues demonstrated the effect of weather, topography and vegetation on the measurement of day/night length, time of solar midnight/noon and the resulting position estimates using light measurements from stationary geolocators at known places and from geolocators mounted on birds.

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Issue 3.2

Aerial photograph of a forest

Cover image for issue 3.2
© Getzin & Wiegand – Biodiversity Exploratories

About the issue

With topics ranging from phylogenetic analysis to statistics and distribution modelling, conservation, citizen science, surveys, genetic and demographic models to avian biology, our issue 3.2 should be of interest to most ecologists and evolutionary biologists. The issue also contains 5 free applications.

About the cover

This very high-resolution image of a beech-dominated forest in central Germany was taken by an unmanned aerial vehicle (UAV) at 250 meter above ground. In this photograph one can clearly recognize individual tree crowns and even smallest gaps. UAVs are increasingly used for ecological surveys because they provide extremely fine resolutions and thus allow the identification of previously undetected object details. Furthermore, UAVs can be considered as very cost-effective tools for the acquisition of data that can be used also very flexibly.

In Assessing biodiversity in forests using very high-resolution images and unmanned aerial vehicles Getzin, Wiegand and Schöning tested the hypothesis that gap-structural information on aerial images can be principally used for the ecological assessment of understorey plant diversity in forests. The authors demonstrate that spatially implicit information on gap shape metrics is indeed sufficient to reveal strong dependency between gap patterns as a filter for incoming light and plant biodiversity. The study highlights that understorey biodiversity can be actively controlled by the spatial quality, and not just quantity, of tree removal. Thus, even under the same quota of tree harvesting, the promotion of complex and irregularly shaped gaps may be beneficial to foster biodiversity in forests.

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Explaining the cover image for issue 3.1

African dwarf crocodiles

Cover image for issue 3.1

The African dwarf crocodile (Osteolaemus tetraspis) is endemic to closed-canopy forests of Central and West Africa and is the smallest of the world’s true crocodiles. The species is difficult to study in the wild and therefore poorly known, but likely plays an important ecological role as a top aquatic predator in cool water forest systems.  The dwarf crocodile is also a major food and economic resource to local people and, as a result, is threatened with overhunting for the bushmeat trade.  The image depicts a collection of young dwarf crocodiles, possibly representing three cohorts, measured in a capture-recapture study in Loango National Park, Gabon.

The article linked to the image is On thinning of chains in MCMC by William Link and Mitchell Eaton. In the article, the authors caution against the routine practice of thinning chains in Markov chain Monte Carlo  (MCMC) simulations. Many analysts, recognizing that MCMC precision decreases as the autocorrelation of the chains increases, routinely thin (sub-sample) their chains. Thinning reduces autocorrelation, but the associated gains in precision are more than offset by the reduction in chain length. Thinning of chains is therefore wasteful, though occasionally justified under circumstances discussed in the article.

To illustrate, the authors refer to a recent application (Eaton and Link 2011, Ecological Applications) in which they applied Bayesian multimodel inference to evaluate two growth models used to estimate individual dwarf crocodile age from capture-recapture data.  They demonstrate analytically that thinning their model-selection chains would have decreased autocorrelation but would also decrease the precision with which posterior model probabilities were approximated.

The young dwarf crocodiles were photographed by Mitchell Eaton in 2004.

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Explaining the cover image for issue 2.6

A lichen crust community

Cover image for issue 2.6

The cover image for the last issue of the year of Methods in Ecology and Evolution is a biological soil crust (BSC), a community which may be composed by mosses, lichens, liveworths fungi and bacteria that are prevalent in drylands worldwide.

Lichen-dominated BSCs (like the one in the image) affect multiple ecosystem functions in those habitats where they are present, including carbon and nitrogen cycling, soil stabilization, and water infiltration and runoff.

The article linked to the image is Randomization tests for quantifying species importance to ecosystem function by Nicholas Gotelli, Werner Ulrich and Fernando Maestre. In the article the authors introduce randomization tests for evaluating the effect of individual species on ecosystem variables measured in multiple plots. This approach is tested using data on ecosystem functioning in lichen-dominated BSC assemblages from central Spain, and further validated using an independent microcosm experiment. The method proposed in this article provides a simple index and statistical test of species importance that can form the basis for additional hypothesis tests and experimental studies of species occurrence and ecosystem functioning.

This BSC-forming lichen community was photographed by Fernando T. Maestre in gypsum outcrops from Sax (South East Spain).

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Explaining the cover image

Wildebeast graze on the cover of MEE 2.5The cover image for Issue 2.5 of Methods in Ecology and Evolution depicts a group of migratory wildebeest, Connochaetes taurinus, photographed in northern Tanzania.

The image was one of two supplied by Thomas Morrison, Dartmouth College, NH, which together excellently convey “the challenging nature of individual wildebeest identification”.

They accompany Estimating survival in photographic capture–recapture studies: overcoming misidentification error by Thomas A. Morrison, Jun Yoshizaki, James D. Nichols and Douglas T. Bolger.

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Explaining the cover image

Our newest issue’s striking cover image is an example of the graphical output of PASSaGE 2, an application providing a broad array of spatial statistical analyses not commonly found in other software packages or GIS software, documented in this edition of Methods in Ecology and Evolution. In this case, the image represents a colour-graded surface map of elevation data.

The citable reference for PASSaGE: Pattern Analysis, Spatial Statistics and Geographic Exegesis. Version 2, by Michael S. Rosenberg and Corey Devin Anderson, is available for free from Wiley Online Library, while the software and user manual are available from the PASSaGE project website.

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