Tag Archives: Demography

Demography Beyond the Population Webinar: Register for Free Now

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Webinar logoRegister for FREE for the first ever BES Publishing webinar based on our forthcoming Demography Beyond the Population Special Feature.

This hour long webinar will begin at 1pm (GMT) on Tuesday 1 March. It highlights some of the excellent articles soon to be published in the British Ecological Society journals Special Feature entitled “Demography Beyond the Population”. The Special Feature is a collaborative effort including articles in all six BES journals. This is the first time such a large ecological collaboration has been attempted worldwide. Using a cross-journal approach has allowed us to highlight the strongly interdisciplinary nature of the field of demography to its fullest potential as well as to lay down the foundations for future directions at the interface of ecology, evolution, conservation biology and human welfare. The webinar has several international speakers and will discuss the articles in the Special Feature and the implications for demography research going forward. Continue reading →

Models, Practical Management and Invasive Critters

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POST PROVIDED BY NICK BEETON

How Simple Should a Model Be?

Should scientists make simplifying assumptions in complex models? This is a debate as old as the hills, and one that everyone seems to have strong opinions about. Some argue that because even the most simplistic model based on the best available estimates is objective, it is better than relying solely on “gut feelings”. In such a model, estimates based on expert opinion or simplifying assumptions can at least be included in a transparent fashion. Others argue that such an approach can miss important emergent properties as a result of missed complexity, making any results misleading and potentially even worse than not using a model at all.

Models to Support Management: Invasive Horses, Cats and Deer

Wild horses in the Australian alps. © Regina Magierowski

Wild horses in the Australian Alps. © Regina Magierowski

Both sides are right in their own way, of course, but perhaps unusually (as an applied mathematics graduate working in ecology), I’ve found myself leaning towards the former view as my career progresses. During my last postdoc, I was confronted with a large, vexing problem: the incursion of wild horses in the Australian Alps. The species was already impacting bogs and wetlands, overpopulated in some places to the point of starvation, and spreading to previously pristine areas of National Park. The issue was (and still is) highly contentious, with activists applying considerable political pressure against lethal forms of control. Knowledge of population densities across the horses’ range was patchy and ability to predict their likely movements equally unreliable. Even predicting their demographics was difficult, with most values for population growth rates conflicting and spatially variable. Continue reading →

Issue 6.12

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Issue 6.12 is now online!

The December issue of Methods is now online! 

Our final issue of 2015 contains one Applications article and two Open Access articles, all of which are freely available.

– stagePOP: A tool for predicting the deterministic dynamics and interactions of stage-structured populations (i.e. where the life cycle consists of distinct stages, for example eggs, juveniles and reproductive adults). The continuous-time formulation enables stagePop to easily simulate time-varying stage durations, overlapping generations and density-dependent vital rates.

Julia Cherry et al. provide one of this month’s Open Access articles. In ‘Testing sea-level rise impacts in tidal wetlands: a novel in situ approach‘ the authors describe the use of experimental weirs that manipulate water levels to test sea-level rise impacts in situ and at larger spatial scales. This new method can provide more robust estimates of sea-level rise impacts on tidal wetland processes. This article was accompanied by a press release when it was published in Early View. You can read more about this article here.

Our September issue also features articles on Biodiversity, Demography, Predator-Prey Interactions, Animal Communication and much more. Continue reading →

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

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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 →

BES 2015 Annual Symposium: Demography Beyond the Population

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Demographic methods and population modeling have been popular tools amongst ecologists for a long time. Recent advances, some of which have been written about in the pages of Methods, have allowed these approaches to be applied to a wide range of questions, helping to integrate population-level processes more broadly into ecological research.

Continue reading →

Issue 6.1

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Issue 6.1 is now online!

Our first issue of 2015 is now online!

This month we include one freely available Applications article:

– A biochemical approach for identifying plastics exposure in live wildlife

We also have two wonderful Open Access papers, ‘Evaluation and management implications of uncertainty in a multispecies size-structured model of population and community responses to fishing‘ by Robert B. Thorpe, Will J. F. Le Quesne, Fay Luxford, Jeremy S. Collie and Simon Jennings and ‘Split diversity in constrained conservation prioritization using integer linear programming‘ by Olga Chernomor, Bui Quang Minh, Félix Forest, Steffen Klaere, Travis Ingram, Monika Henzinger and Arndt von Haeseler.

This month’s cover image shows more than 170 plastic pieces that were found in the digestive system of a single deceased seabird. Plastic items this seabird ate included industrial pellets (‘nurdles’) that are just a few millimeters long, drink bottle lids, ties used for helium balloons, a plastic doll’s arm and numerous other plastic pieces, some more than 55 mm in length. We can necropsy deceased birds to find out what they have eaten as they forage in the open ocean. However, to understand the pervasiveness of plastics in the marine environment and the potential impacts to wildlife, non-destructive sampling is key.

There is a new method to assess the ubiquity of plastics ingestion in seabirds. A simple swabbing technique, coupled with gas-chromatography/mass spectrometry, can be used to identify phthalate plasticizers that have been adsorbed into the preening oil of seabirds.The approach is quick, simple and can be used on live, wild-caught individuals without harm, serving as an effective tool to help manage declining, threatened or endangered species.

You can read more about this swabbing technique in Hardesty et al.’s ‘A biochemical approach for identifying plastics exposure in live wildlife‘, which is available free of charge.
Photo © Britta Denise Hardesty, CSIRO.

To keep up to date with Methods newest content, have a look at our Accepted Articles and Early View articles, which will be included in forthcoming issues.