Pyramids of species richness

This post is written by PhD student Shaun Turney, and highlights a recent publication from the lab.

Two years ago, I was finishing my MSc and considering whether I’d like to do a PhD, and if so, with whom. I met with Chris and we threw around a few ideas for PhD projects. It was when he brought up a certain mystery that my decision to do a PhD in his lab was cemented. The mystery? Chris and his former PhD student Crystal Ernst were puzzled why there seem to be so many carnivores on the Arctic tundra, and relatively few herbivores to feed them.

How could it be possible? Is there a high level of cannibalism? (But then it would be like pulling oneself up by ones bootstraps — how does the energy and biomass enter the carnivore population in the first place?) Are the carnivores really omnivores? Is our methodology for sampling the tundra biota biased towards carnivores? Is the transfer of energy from herbivores to carnivores somehow more efficient (less energy loss) than in other ecosystems? These sorts of questions touch on some fundamental questions in ecology and I was hooked.

Shaun Turney, vacuuming the Tundra.

Shaun Turney, vacuuming the Tundra.

It seemed to me the logical first step would be to find out what is a typical predator-prey ratio. In what proportions are the organisms in an ecosystem divided up from plant (lowest trophic level) to top predator (highest trophic level)? The answer to that questions has already been very much explored when it comes to biomass and abundance. Charles Elton explained about 80 years ago that typically the mass and number of organisms form “pyramids”: They decrease with trophic level because energy is lost with each transfer from resource to consumer. But what about diversity? How does the number of species change with trophic level?

I decided to look at the food webs in the data base GlobalWeb to answer this question, and we just published a paper in Oikos on this topic. I found that typically ecosystems form “pyramids of species richness”, just like the pyramid of numbers and pyramid of biomass described by Elton. But some types of ecosystems, notably in terrestrial ecosystems, we can consistently observe a uniform distribution or even an “upside-down pyramid” rather than a pyramid like Elton described. That is, there are consistently cases where there more carnivore species than herbivore species in an ecosystem.

An example of aquatic compared to terrestrial food-web structure (from Turney and Buddle)

An example of aquatic compared to terrestrial food-web structure (from Turney and Buddle)

So evidently, at least when it comes to diversity, the pattern that Chris has observed in the tundra is not so unusual! The next step for me is to try to figure out why. Stay tuned!

Reference:

Turney S and CM Buddle. Pyramids of species richness: the determinants and distribution of species diversity across trophic levels. Oikos. DOI: 10.1111/oik.03404

 

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Insect herbivory in fragmented forests: it’s complicated

I’m excited to announce a recent paper to come out of the lab, by former PhD student Dorothy Maguire, and with Dr. Elena Bennett. In this work, we studied the amount of insect herbivory in forest patches in southern Quebec: the patches themselves varied by degree of fragmentation (ie, small versus large patches) and by connectivity (ie, isolated patches, or connected to other forest patches). We studied herbivory on sugar maple trees, both in the understory and canopy, and at the edges of the patches. Our research is framed in the context of “ecosystem services” given that leaf damage by insects is a key ecological process in deciduous forests, and can affect the broader services that forest patches provide, from supporting biodiversity through to aesthetic value. Dorothy’s research was part of a larger project about ecosystem services and management in the Montérégie region of Quebec.

 

Maguire_Canopy.JPG

Dorothy Maguire sampling insects in the tree canopy (Photo by Alex Tran)

The work was tremendously demanding, as Dorothy had to select sites, and within each site sample herbivory at multiple locations, including the forest canopy (done with the “single rope technique). Dorothy returned to sites many times over the entire summer to be able to assess trends over time. Herbivory itself was estimated as damage to leaves, so after the field season was completed, thousands of leaves were assessed for damage. The entire process was repeated over two years. Yup: doing a PhD requires a suite of skills in the field and lab, and there is no shortage of mind-numbing work… Dedication is key!

As with most research, we had high hopes that the results would be clear, convincing, and support our initial predictions – we certainly expected that forest fragmentation and isolation in our study landscape would have a strong effect on herbivory – after all, our study forests varied dramatically in size and isolation, and herbivory is a common and important ecological process, and insect herbivores are known (from the literature) to be affected by fragmentation.

 

QuebecLandscape

The landscape of southern Quebec. Lots of agriculture, some patches of forest.

 

However, as with so much of ecological research, the results were not straightforward! “It’s complicated” become part of the message: patterns in herbivory were not consistent across years, and there were interactions between some of the landscape features and location within each patch. For example, canopies showed lower levels of herbivory compared to the understory, but only in isolated patches, and only in one of the study years! We also found that edges had less herbivory in connected patches, but only in the first year of the study. Herbivory also increased as the season progressed, which certainly makes biological sense.

So yes, it’s complicated. At first glance, the results may appear somewhat underwhelming, and the lack of a strong signal could be viewed as disappointing. However, we see it differently: we see it as more evidence that “context matters” a great deal in ecology. It’s important not to generalize about insect herbivory based on sampling a single season, or in only one part of a forest fragment. The story of insect herbivory in forest fragments can only be told if researchers look up to the canopy and out to the edges; the story is incomplete when viewed over a narrow time window. In the broader context of forest management and ecosystem services, we certainly have evidence to support the notion that herbivory is affected by the configuration of the landscape. But, when thinking about spatial scale and ecosystem processes, careful attention to patterns these processes “within” forest patches is certainly required.

We hope this work will inspire others to think a little differently about insect herbivory in forest fragments. Dorothy’s hard work certainly paid off, and although the story is complicated, it’s also immensely informative and interesting, and sheds light on how big landscapes relate to small insects eating sugar maple leaves.

Reference:

Maguire et al. 2016: Within and among patch variability in patterns of insect herbivory across a fragmented forest landscape. PlosOne DOI: 10.1371/journal.pone.0150843

 

Monitoring northern biodiversity: picking the right trap for collecting beetles and spiders

Ecological monitoring is an important endeavour as we seek to understand the effects of environmental change on biodiversity. We need to benchmark the status of our fauna, and check-in on that fauna on a regular basis: in this way we can, for example, better understand how climate change might alter our earth systems. That’s kind of important.

A northern ground beetle, Elaphrus lapponicus. Photo by C. Ernst.

A northern ground beetle, Elaphrus lapponicus. Photo by C. Ernst.

With that backdrop, my lab was involved with a Northern Biodiversity Program a few years ago (a couple of related papers can be found here and here), with a goal of understanding the ecological structure of Arthropods of northern Canada. The project was meant to benchmark where we are now, and one outcome of the work is that we are able to think about a solid framework for ecological monitoring into the future.

A few weeks ago our group published a paper* on how to best monitor ground-dwelling beetles and spiders in northern Canada. The project resulted in over 30,000 beetles and spiders being collected, representing close to 800 species (that’s a LOT of diversity!). My former PhD student Crystal Ernst and MSc student Sarah Loboda looked at the relationship between the different traps we used for collecting these two taxa, to help provide guidelines for future ecological monitoring. For the project, we used both a traditional pitfall trap (essentially a white yogurt container stuck in the ground, with a roof/cover perched above it) and a yellow pan trap (a shallow yellow bowl, also sunk into the ground, but without a cover). Traps were placed in grids, in two different habitats (wet and “more wet”), across 12 sites spanning northern Canada, and in three major biomes (northern boreal, sub-Arctic, and Arctic).

Here’s a video showing pan traps being used in the tundra:

Both of the trap types we used are known to be great at collecting a range of taxa (including beetles and spiders), and since the project was meant to capture a wide array of critters, we used them both. Crystal, Sarah and I were curious whether, in retrospect, both traps were really necessary for beetles and spiders. Practically speaking, it was a lot of work to use multiple traps (and to process the samples afterwards), and we wanted to make recommendations for other researchers looking to monitor beetles and spiders in the north.

The story ends up being a bit complicated… In the high Arctic, if the goal is to best capture the diversity of beetles and spiders, sampling in multiple habitats is more important than using the two trap types. However, the results are different in the northern boreal sites: here, it’s important to have multiple trap types (i.e., the differences among traps were more noticeable) and the differences by habitat were less pronounced. Neither factor (trap type or habitat) was more important than the other when sampling in the subarctic. So, in hindsight, we can be very glad to have used both trap types! It was worth the effort, as characterizing the diversity of beetles and spiders depended on both sampling multiple habitats, and sampling with two trap types. There were enough differences to justify using two trap types, especially when sampling different habitats in different biomes. The interactions between trap types, habitats, and biomes was an unexpected yet important result.

Our results, however, are a little frustrating when thinking about recommendations for future monitoring. Using more than one trap type increases efforts, costs, and time, and these are always limited resources. We therefore recommend that future monitoring in the north, for beetles and spiders, could possibly be done with a trap that’s a mix between the two that we used: a yellow, roof-less pitfall trap. These traps would provide the best of both options: they are deeper than a pan trap (likely a good for collecting some Arthropods), but are yellow and without a cover (other features that are good for capturing many flying insects). These are actually very similar to a design that is already being used with a long-term ecological monitoring program in Greenland. We think they have it right**.

A yellow pitfall trap - the kind used in Greenland, and the one we recommend for future monitoring in Canada's Arctic.

A yellow pitfall trap – the kind used in Greenland, and the one we recommend for future monitoring in Canada’s Arctic.

In sum, this work is really a “methodological” study, which when viewed narrowly may not be that sexy. However, we are optimistic that this work will help guide future ecological monitoring programs in the north. We are faced with increased pressures on our environment, and a pressing need to effectively track these effects on our biodiversity. This requires sound methods that are feasible and provide us with a true picture of faunal diversity and community structure.

It looks to me like we can capture northern beetles and spiders quite efficiently with, um, yellow plastic beer cups. Cheers to that!

Reference

Ernst, C, S. Loboda and CM Buddle. 2015. Capturing Northern Biodiversity: diversity of arctic, subarctic and northern boreal beetles and spiders are affected by trap type and habitat. Insect Conservation and Diversity DOI: 10.1111/icad.12143

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* The paper isn’t open access. One of the goals of this blog post is to share the results of this work even if everyone can’t access the paper directly. If you want a copy of the paper, please let me know and I’ll be happy to send it to you. I’m afraid I can’t publish all of our work in open access journals because I don’t have enough $ to afford high quality OA journals.

** The big caveat here is that a proper quantitative study that compares pan and and pitfall traps to the “yellow roof-less pitfall” traps is required. We believe it will be the best design, but belief does need to be backed up with data. Unfortunately these kind of trap-comparison papers aren’t usually high on the priority list.

Ecology from geology

I recently asked a geologist* to come to speak to my field biology class. The course is about the “St Lawrence Lowlands“, and throughout the term we visit farms, forests, lakes and streams, and we do natural history research.

Why then, do I have a geologist come and speak to us?

A result of glacial till: it's now supporting biodiversity.

A result of glacial till: it’s now supporting biodiversity.

Ecology is built upon geology. This may seem obvious, but requires a deeper discussion: after hearing this guest lecture year after year, I no longer see my local landscape as some farm fields, patches of forests, and some big bodies of water**. I see lands and waters shaped by a history before our time. The local landscape is a product of past geological events. We have farm fields around the Montérégie because the Champlain Sea deposited its sediments and after it departed; what remained is a flat expanse, perfect for farming. As the sea departed, it left behind remnants of beaches still visible today, as the Plateau district of Montreal, or where apple orchards grow next to Mont St Hilaire. We have some slight elevation here and there because of sandy deposits left by the departure of the last great glacier that covered our land in the very recent past. That’s where we find great white pines, stretching up above the canopies of the deciduous trees. We have Mount Rigaud because of processes hundreds of millions of years ago: an igneous intrusion that happened long, long before the age of dinosaurs. More recent igneous intrusions created the Lachine rapids, historically important as this became a key place where First Nations people, and later Europeans, set up camp along their journey up or down the big river. This was the one of the birthplaces of Montreal.

Our landscape, and the ecology of our landscape, is built upon slow but incredible processes, and I think biologists don’t consider those processes as dynamic forces that are constantly influencing our current view of the world. Ecologists often think of time in scales of decades or centuries, and we spend considerable time looking at time frames that resonate with our own life spans (in contrast, evolutionary biologists and taxonomists look much further back, and are accustomed to time frames of ‘millions of years’. I think We need to meet in the middle a little more).

As field biologists, knowing the origin of those big rocks in the forest matters a great deal: glacial till from the past creates habitats today. Moss creeps on these ancient boulders; centipedes and spiders crawl underneath. Their ephemeral life depends on much longer time frames. It’s hard to imagine how to consider discussion land management or wildlife conservation in the region without appreciating how past geological events can either help or hinder the process. There’s a geological reason why soil development is slow in some parts of our local ecosystems; why the land may be rocky, and why it’s well-drained in some areas, and wet in others. This affects long-term planning around wildlife preserves, or housing developments. There’s good reason why Mont St Hilaire is a biosphere reserve, and how it’s flora and fauna will be different that what we find elsewhere in the St Lawrence Lowlands.

Hiking at Mont St Hilaire: there are so many reasons why it's a special place, including geology.

Hiking at Mont St Hilaire: there are so many reasons why it’s a special place, including geology.

The longer I spend living here and learning about my region’s natural history, the more I recognize the value of some knowledge about geology, and this is why I have a geologist give a guest lecture. The students also tell me, year after year, that they appreciate and value this perspective, and their understanding of this part of the world is enriched by a deeper discussion about ‘why’ the St Lawrence Lowlands exists as it does.

How often do ecological classes include discussion about geology? Perhaps not often enough.
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*the geologist in question is Dr. George McCourt, who teaches often in the McGill School of Environment. I am immensely thankful for him taking time to teach us about his passion.

**when I commute to work, this is what I see: forests, field and lakes. Others in the St Lawrence Lowlands will have a different story, perhaps one that involves highrises and concrete.

Landscape structure, insect herbivory, and ecosystem services

I’m pleased to announce a new publication to come out of the lab, with lead author Dorothy Maguire and co-authored by Elena Bennett and Patrick James. In this work, Dorothy ponders and writes about the broader implications of insect herbivory. More specifically, how insect herbivory is affected by landscape connectivity (i.e., the degree to which habitats are linked to each other), and how plant-feeding insects may relate to ecosystem services (i.e., the values and services that humans get from our natural systems).

Female (l) and male (r) Gypsy moth, caught in the act.

Important insects when, as caterpillars, eat a lot of foliate: Female (l) and male (r) Gypsy moth, caught in the act.

We certainly know that insects can do all kinds of damage to plants in ecosystems, but do insects in more (or less) connected habitats do more damage? To address this question Dorothy scoured the literature and got the relatively unsatisfactory answer of “sometimes”: 49% of the papers suggest increased connectivity relates to more insect herbivory and 28% of the papers show less herbivory in more connected patches. The lack of a clear answer actually makes quite a bit of sense since every context can be quite different, and not all insects are equal. It is hard to generalize since effects in forests will not be the same as in fields, and insects that are out-breaking (i.e., with major population explosions) may be affected differently than non out-breaking species. Dorothy certainly found these contexts were important. The results were important to illustrate how we need to adapt any management options with close attention to both landscape feature and their interaction with the life-history of the herbivore.

The second part of Dorothy’s work delved deeper into the literature to ask about the effects of out-breaking versus non out-breaking herbivore species on a select suite of forest ecosystem services: effects on timber production, aesthetics, soil formation and Carbon sequestration. There were some interesting results of this and again, any particular effect of herbivory on an ecosystem service was highly sensitive to the outbreak status of the herbivore. For example, the aesthetics of a forest can be positively affected by low levels of herbivory since this may help create pleasant conditions for light infiltration to the forest floor. However, an out-breaking species may defoliate a tree more completely, thus reducing the aesthetic value. Another example is that low levels of herbivory may positively affect timber production because trees may show “compensatory” growth after light feeding by an insect. In contrast, timber production will be negatively affected by high levels of defoliation as this may reduce a tree’s ability to grow. Although some of these results may seem rather logical, Dorothy’s work was unique as it showed how the scientific literature supports the connections between a herbivore’s life-history and key ecosystem services.

Screen Shot 2015-06-11 at 6.55.21 AM

Visual representations of the hypothesized relationships between insect herbivory and ecosystem services. Specifically (a) timber production, (b) aesthetic value of forests. Graphs are divided into four sections representing positive and negative effects of herbivory on ES, during non-outbreak (low) vs. outbreak (high) levels of herbivory. Quadrants are coloured differently based on the hypothesized strength of the effect of herbivory on ES: weak (light grey), moderate (dark grey) and strong (black). Proposed relationships are derived from synthesis of the available literature. From Maguire et al.

The last part of the work was focused on building a conceptual framework – a framework that ties together landscape structure, the process of herbivory, and ecosystem services. This is meant to be a road map for any stakeholders with an interest in any or all of those factors. For example, should a forest manager be tasked with understanding how to increase or support a particular ecosystem service, she or he needs also to recognize how that service is tied to important processes such as herbivory, and the related connections to the broader landscape.

Screen Shot 2015-06-11 at 7.05.34 AM

This work is novel and important because it links the well known process of insect herbivory to concepts of ecosystem services and to the discipline of landscape ecology. The marrying of these areas is critically important as we face increasing pressures on our natural systems, and the complexity of the systems can be overwhelming. We hope this work piques more interest in this topic, and that the framework Dorothy provides is useful to all the stakeholders.

Reference:

Maguire, DY, PMA James, CM Buddle & EM Bennett Landscape connectivity and insect herbivory: A framework for understanding tradeoffs among ecosystem services. Global Ecology and Conservation. doi:10.1016/j.gecco.2015.05.006

 

Expanding boundaries and increasing diversity by teaching with technology

“As teachers, technology encourages us to be more creative, more influential, and more mindful of the implicit and explicit impacts our words have on students, and to explore new ways to make our classrooms more diverse”.

That’s a quote from a paper by Josh Drew, published last week. In this paper, Drew provides some fascinating case studies about how teaching with technology can help break down some strong barriers in higher education, with a focus on STEM disciplines. For example, students from the LGTBQ community, visible minorities, and other marginalized groups are often at a distinct disadvantage in a university context, whether it’s lack of access, finances, support, or mentorship. Drew argues that teaching with attention to this problem, and in a way that embraces diversity, is critically important, but is also a challenge. Technology can be a potential facilitator for this, and help overcome the challenge. To help other instructors, we need creative ideas, approaches and case studies, which is what Drew provides.

In the first case study, Drew gives an example of a marine conservation course that pairs students from a poor neighbourhood of Chicago with students from Fiji and through online resources, student learn content together, and do group projects with their peers. I was most impressed with how the capstone project in this course meant the students needed to problem solve with other students who were from entirely different cultures – something that is very difficult in a more traditional classroom setting. Typical courses in STEM seldom embrace a learning context that literally connects students from around the world.

The second case study focuses on how Drew used Twitter to continue teaching at Columbia University after hurricane Sandy hit New York in 2012, and many students could not get to class. Students were given access to class notes via Figshare, and lectures were delivered in 140 character packets. Given the open format, the tweets could be viewed by anyone in the world, which created an inclusive learning environment for everyone, whether registered in the class, or not. Although this is a more indirect way of teaching with attention to diversity, Drew argues that Twitter is an effective tool to help break down barriers and can be used effectively to increase student engagement. (The Twitter course was, by the way, how I got to know Josh Drew on Twitter, and his example helped me shape my own teaching with Twitter).

Active Learning: Watisoni Lalavanua (l) and Josh Drew (r) [tweeting!] at the Suva Fish Market, identifying species and talking about the best way to manage fisheries based in their life histories.

Active Learning: Watisoni Lalavanua (l) and Josh Drew (r) [tweeting!] at the Suva Fish Market, identifying species and talking about the best way to manage fisheries based in their life histories.

The third case study was a hands-on marine conservation workshop in Fiji, held jointly by Columbia University and the University of the South Pacific. The “real world” aspect of the course was facilitated by simple and inexpensive scientific equipment, and had a focus on open-access data by the participants. Of note, the students in the workshop were from six different countries, brought together to work on conservation priorities of relevance to the South Pacific. This case study certainly resonated with me, as I try to have my students tackle projects in the field (with all its challenges) as this provides a rich learning opportunity for all. However, unlike my course in Montreal, Drew’s example includes a very unique cultural experience for the participants. Teaching and learning in different places certainly embraces diversity in STEM, and although not always practical or feasible, such opportunities should be sought and supported.

In sum, Drew’s paper resonated strongly for a few reasons. The case studies are themselves great examples for all of us involved in teaching in higher education. The technological aspects are relatively straightforward and inexpensive, and many of tools highlighted are accessible. I appreciated his arguments at the end of the paper about ensuring accessibility; instructors must pay attention to ensuring class participants are able to get and use the tools, especially when thinking about students access to computers, smartphones, data plans and WIFI.

Perhaps the part that spoke to me the most was thinking about how technology can be a facilitator for increased diversity and inclusiveness in the classroom. I must be honest in saying that I don’t typically consider my own teaching with technology thought this lens, but I am now starting to look at this differently. Not all students from all communities will face a traditional classroom in the same say, and the “podium style” of teaching and learning in higher education may really marginalize some people more than they already are. Online classrooms, Twitter and active learning in partnership with peers are great examples of ways to open up our universities regardless of potential constraints, whether they be economics, race, culture or gender identification.

Thanks, Josh Drew, for making me pause and reflect, and for giving us all some good ideas.

Reference:

 Drew, J. Using technology to expand the classroom in time, space and diversity. Integr. Comp. Biol. (2015) doi: 10.1093/icb/icv044

Unanswered (Arachnological) research questions

Scientific research produces more questions than answers (at least in my experience!), and a neat paper, project or field season often leaves us with a suite of new directions to take a research program. I wish I had more time to answer some of these questions, but reality sets in: curious questions that arise aren’t always feasible, or perhaps the timing isn’t right, or the ideas aren’t funded(able), or interest from students or collaborators isn’t there. I have come to the realization that perhaps I shouldn’t keep these questions in my head, but instead should write them down, publicly. Perhaps these ideas will generate ideas for others, point me to literature on these topics, or at the very least it will help me to refine and rethink these questions. After all, coming up with a good research question is certainly one of the more challenging parts of the research process, and improving a question starts with taking a stab at formalizing it on paper.

Disclaimers:

1) I did not do any kind of extensive literature search to see whether these questions have been tackled already.

2) I think many of these questions are rather poorly formed, which is perhaps why they have not yet been answered…

Ok, so here goes, and I will start* with a few questions with an Arachnological flare:

Do Linyphiidae spiders *really* show higher diversity at more northern latitudes? This is a classic biogeographic question, and there have been hints and ideas that Linyphiidae spiders (aka “micro sheet-web spiders”, one of the most diverse families of spiders, generally small-bodied, ground-dwellers) show a reverse latitudinal trend, with fewer species in temperate regions compared to the tropics. My own lab’s research certainly supports the claim that Linyphiidae spiders dominate diversity in the North, but are they really less diverse further south?  Although this question has been partially answered at large(ish) spatial scales, I think we need to go BIGGER to truly unravel this one, and it needs to be done with sampling methods that are really comparable (i.e., standardized), along a gradient that runs from the tropics towards the poles.

What is the relationship between fang “size” in spider species and their relative venom strength? This seems like an obvious question but has perhaps not been answered. I am curious about this because I know some “small-fanged” spiders (eg, some crab spiders in the family Thomisidse) can really pack a punch, and I have heard that some larger spiders have relativity mild venom, despite the size of their fangs. I am not sure how easy it would be to answer this one: the literature about venom is probably scarce for most species, and I’m not even sure how to test for “venom strength”, or to properly quantify fang size. This question would also have to be addressed with close attention to phylogeny.

 

Check out these fangs! (and venom…). Photo by Alex Wild

In the canopy of temperate, deciduous forests, where do the spiders come from? My lab has done a fair bit of work on canopy spiders, and their dispersal abilities, but I’m just not sure where spiders come from each spring. This is particularly relevant in my region because of the strong seasonality and harsh winters. I see three options: they colonize tree-tops from afar, they climb up the tree trunk each spring from the understory, or they overwinter in the canopy. Some manipulative experiments shows some winter-active birds feed on spiders in trees, suggesting some certainly might overwinter. However, I do wonder if this is commonplace in the systems I know around Montreal. This could be a great project, and would involve perhaps tagging spiders, using population genetics, or doing some good old fashion natural history observations.

What is the relatedness of different populations of synanthropic spider species such as Salticus scenicus (the “zebra jumper“)? Many spiders are “urban” spiders, and occur frequently in association with humans. When did they arrive to these cities? Does the age (and relatedness) of each city’s population of zebra jumpers relate to the age of a city? (Eg, compare a newish city like Calgary to an older city like New York…?). When looking at population genetics, do individuals move around a lot within a city (I suspect not), or between cities (I have no idea…). This would be a neat project, in part because of the attractiveness of the spider and its close association with humans, but also because it would be feasible! I think the methods could be quite straightforward, and would address a really interesting aspect of invasive species ecology.

A cute little zebra jumper! Photo by Alex Wild.

When ballooning, how frequently do spiders take off again after they land? Spiders disperse all the time by releasing strands of silk and “sailing away”, and they certainly aren’t restricted to one flight. There has been fabulous research done about their dispersal potential and habitat suitability at a landscape scale, but I am very curious about how often they land in a location only to depart again soon after. Why would they do this? Perhaps they don’t like their landing spot, perhaps there is a competitor or predator nearby, or perhaps they just feel like it. What clues do they use to leave a spot after they land in a spot? I really have no idea how to answer this kind of question….

Why do Pseudoscorpions tend to exhibit such clumped distributions? These tiny creatures are truly fascinating, and the basic biology and distribution of most species remains unknown. I have spent a lot of time searching for and collecting Pseudoscorpions, and I have found that their local populations are incredibly “clumped”. In general terms this means you can search for a long, long time and never find any individuals and then suddenly happen upon dozens. This alone is not unusual for many animals, but I have found Pseudoscorpions to be more patchy in their distribution compared to other arthropod taxa I have spent time searching for. Why is this? Maybe I am just really unlucky or hopeless when it comes to collecting these arachnids? Perhaps their low dispersal abilities keeps them from expanding their local range (they can’t fly or walk very quickly)?  However, many are phoretic and catch rides on other animals that can disperse effectively. Maybe Pseudoscorpions have very specific niches, and perhaps those niches are relatively rare? I just don’t know.

Ok, that’s it for now…

I do hope someone out there tackles some of the unanswered questions, or corrects me if I’ve missed some key literature on these topics. Please share, comment and provide input! I also urge others to post their unanswered research questions – theses ideas need to be written down and discussed. I think we will all benefit.

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* There will surely be a Part 2, and I think this blog is a good place to throw ideas out there. It can be a type of “research notebook”, which can and should include unanswered (or unanswerable) research questions.

© C.M. Buddle