Category: Research

Ponds are dynamic habitats, which makes it tough to conserve biodiversity…

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Background:  When an area is designated as a site for conservation or special scientific interest that is usually because one or more species of interest have been found or the community as a whole is unique or exceptional. However, the implicit assumption in this approach is that if you come back tomorrow then those species or that community will still be present. If the habitat is dynamic, with frequent population-level extinctions and colonisations, then it may be that this assumption does not hold. Pond ecosystems represent one case where the habitats are small and relatively easily affected by external variables and which may, as a result, vary in their conservation value over time.

What we did: Andrew Hull and Jim Hollinshead have been monitoring ponds in Cheshire (northwest England) for almost 20 years. A set of 51 ponds were surveyed in 1995/6 and again in 2005, meaning that we can test whether or not over this 10-year period there was any change in the conservation value of the ponds. Pond surveys recorded all plant and macroinvertebrate (i.e. invertebrates larger than about 1mm, which was the size of the mesh of the net) species in the ponds and we compared (i) the diversity, and (ii) the conservation value of the ponds between the two surveys. Plants showed similar levels of diversity in both surveys, so highly-diverse ponds in the first survey remained that way in the second. However, invertebrate diversity was not correlated between surveys, meaning that species rich ponds in the first survey did not necessarily remain that way. For both groups there was not correlation between conservation value (calculated based on the rarity of the species in the community) in survey 1 compared to survey 2.

Importance: Ponds are highly variable ecosystems and that is one of the reasons that they support such a wide range of species on a landscape scale. However, it seems that this variability may make it difficult to conserve them adequately, since conservation value is changing over time. This finding supports the conservation of pond clusters, rather than individual sites, which are more likely to contain a stable species pool.

This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Temporal dynamics of aquatic communities and implications for pond conservation”, was published in the journal Biodiversity and Conservation in 2012. You can find this paper online at the publisher, or on Figshare.

Image credit: Alison Benbow, CC BY 2.0, http://bit.ly/1l35Tdu

Drones and quadcopters in conservation

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I’ve had a bit of a go at using unmanned aerial vehicles (UAVs) in the past (see this little write-up) but with mixed success. Part of the problem is that there has not been any consistent attempt to develop a technology that can be used for environmental or ecological research – just a bunch of scientists trying to MacGyver existing equipment. Now there’s Conservation Drones, who seem to be taking a slight more systematic approach, designing their own drone, spreading the knowledge around, and starting up PhD research projects to develop the tech further. Here’s an early demo of one of their models:

Less common species tend to have more parasites

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Background:  Parasites and the individuals that they attack (called “hosts”) often have a long evolutionary history of interaction. This history often plays-out as an “arms race” where the parasite finds a new way of attacking the host and the host then evolves a defence against that attack, followed by subsequent evolution by the parasite. Not only this, but species of parasites (such as the aquatic mites and protozoa that I work on) that exploit many host species can differentially affect those different hosts. In this study, we were interested in how parasitic protozoa affect closely related damselfly species that differed in their distributions.

What we did: Julia Mlynarek, a PhD student at Carleton University, collected a large number of damselflies from a number of sites around eastern Ontario. The species were grouped into pairs so that we could compare between species from the same genus.  She dissected these to find the number of protozoa (like the one shown above) in guts of each animal. We found that species with smaller geographical distributions tended to have more protozoan parasites than closely related species with larger distributions.

Importance: Explaining how parasites affect their hosts is a big question spanning ecology and evolutionary biology. These results suggest that there might be a combined effect of (i) shared parasites due to evolutionary history, and (ii) varying resistance due to different exposure across geographical ranges.

This is part of a series of short lay summaries that describe the technical publications I have authored.  This paper, entitled “Higher gregarine parasitism often in sibling species of host damselflies with smaller geographical distributions”, was published in the journal Ecological Entomology in 2012. You can find this paper online at the publisher, or on Figshare.

Image credit: Christophe Laumer, CC BY 2.0, http://bit.ly/1rrvyzt

Yet another post about gender and academic conferences

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genderThis is becoming something of a cottage industry recently – it is fairly straightforward to calculate the gender ratio of presenters at academic conferences and to evaluate that ratio against some theoretical baseline. However, these sorts of questions are important to look at because the work is highly complex and so requires a large number of people looking at the diverse kinds of conferences to provide a bigger picture. A number of previous studies have shown a range of different patterns in gender and academic conferences (references at the bottom):Read More »

British dragonflies are emerging earlier in the year under climate change

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Background: A variety of responses to climate change have been detected in a variety of taxa.  Among these is a change in phenology – the timing of the life cycle (like the emergence of an adult dragonfly from its larval case as shown on the right). Since some species use temperature as a cue for when to develop, as the environment warms there is a signal of earlier development in these species.

What we did: I analysed an extensive dataset of sightings of dragonflies and damselflies (Odonata) over a 50-year period in the UK.  These 450,000 sightings were of around 40 species and provided a detailed record of dates on which different Odonata species were emerging from their aquatic habitats.  I found that there was a significant shift towards earlier emergence which was consistent with that observed in terrestrial species.  I further demonstrated that there was a difference between two groups of species that varied in what stage they over-wintered.  Those species that sat in the water over winter as eggs did not show a response to climate change while those that were larvae over winter did show a response.  I infer from this that the response to climate change is caused by a decline in mortality associated with cooler temperatures in the more vulnerable larval stages.

Importance: As I mention above, a number of studies have demonstrated an effect of climate change on the phenology of animals and plants.  This study showed that the signal was present even for animals that occupy aquatic habitats, suggesting that temperature changes influences aquatic and terrestrial ecosystems in much the same way.

This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Historical changes in the phenology of British Odonata are related to climate”, was published in the journal Global Change Biology in 2007 (my first paper!). You can find this paper online at the publisher, or on Figshare.

Image credit: Sally Crossthwaite, CC BY-NC-ND 2.0, http://bit.ly/1q6HYtH

Who would win in a fight between a rhino and a tiger?

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tigerrhinoI got an email from our university press officer earlier this week asking “whether we have a ‘zoologist who could participate in a light-hearted discussion about who would win in a fight between a tiger and a rhino on Friday morning’.” The request was from the local BBC Radio Leeds team who wanted to break up their coverage of the Leeds Rhinos vs Castleford Tigers rugby league Challenge Cup final preparations with some light-hearted digressions. I have resolved to take a more active part in science communication (including this blog), because I see that as a fundamental part of my job (even if it is little-rewarded…) and so I agreed to do it.Read More »

Why I blog (occasionally!)

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There has been a lot of discussion over the merits of academics blogging (see here, here, here, here, here and here). The positive arguments seem to be that:

  1. It’s good outreach, allowing a flexible platform for communication of science
  2. Blogs allow rapid responses and reporting on research
  3. Online profiles are important and blogs can be a strong foothold in internet-space
  4. Writing for a non-technical audience is good practice for science communication

The negative arguments seem to be that:

  1. It doesn’t count in academic terms (it’s not a paper, a grant, or a lecture)
  2. Sometimes tenure panels might see blogging as a waste of time
  3. There’s the danger of “upsetting” people.

Well I think it counts (even if my colleagues disagree), we don’t have tenure in the UK, and I don’t mind upsetting people, so there’s no good reason for me not to blog! I was letting it drop off a bit, but all this discussion has encouraged me to start up again. One of the problems is that I lacked a blogging strategy, which meant that I only shared what I (A) found interesting, and (B) found time to write about. Most of my problem was that I found interesting topics and spent too much time on too few, too niche issues. That’s going to change. Here’s the plan:

  • I’m going to post lay summaries of each of my publications.  That’s 25 to start with, and I’ll add more as I go along. I see that as a vital part of science communication, and I’ll link them back to my publications page on my website.
  • I have recently been immersing myself in Twitter which has led to my discovering a lot more interesting (and sometimes plain weird) papers and articles. This will be a key (near-bottomless) source for new ideas, but I’ll try to keep to a theme.
  • The main topicsare going to be
    • General science things
    • Entomology news and views
    • Education and technology
    • Specific posts about my research
  • Finally, I’m going to write in short form now – no more monthly long reads. 500 words max, and always with an image or video. It was the length and detail that was killing my productivity, and nobody reads those longreads, anyway!

I am hoping that that is going to provide a sustainable flow of content over the next few months, and I’ll reevaluate at Christmas.  Happy reading!

Image credit: Cortega9, CC-BY-SA 3.0, http://bit.ly/1oiVIwr

Study design and mark recapture estimates of dispersal [paper summary]

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This is part of a series of short lay summaries that describe the technical publications I have authored.  This paper, entitled “Study design and mark recapture estimates of dispersal: A case study with the endangered damselfly Coenagrion mercuriale”, was published in the Journal of Insect Conservation in 2012. You can find this paper online at the publisher, or on Figshare.

9303167014_cdbcb32d61_zBackground:  I have long been interested by movement of animals in the landscape and whether or not this can be accurately quantified in the field.  One of the major issues associated with these field studies (such as mark-release-recapture studies, in which animals are marked with a unique tag then recaptured at a later time) is that you cannot detect dispersal distances that are greater than the size of the study area that you are using.  For example, people have been marking damselflies for decades to try to measure how far they fly.  However, if you only look for them 500m from where you first found them, you won’t find them flying any further than that.

What we did: This study used a large mark-release-recapture dataset and investigated the effect that expanding a study area has on the maximum dispersal distance detected.  We found that the original study (on the endangered southern damselfly, Coenagrion mercuriale) was at a scale sufficient to estimate the maximum distance that the insect is able to fly, around 2km.

Importance: This endangered species has very specific habitat requirements (water meadows and shallow ditch systems) which mean that it has a long distance to move between these rare areas.

Image credit: Paul Ritchie, CC BY-NC-ND 2.0, http://bit.ly/1sZpjCC

My first preprint submission

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My last post was about open access – making sure that your work is freely available after publication. However, I have also been experimenting with preprints – posting articles prior to publication for open peer review. PeerJ is one publishing model that has been gaining traction recently. They also offered free publication for a trial window and have a monkey as their mascot, so how could I resist? My paper, “Continental variation in wing pigmentation in Calopteryx damselflies is related to the presence of heterospecifics” is available now (with all the data used in the paper) at the PeerJ preprint site, while the manuscript is in review at the PeerJ journal. I thought it worthwhile reflecting on the experience and my growing support for this idea.Read More »