Summers in the redwood forest

We are excited to welcome Matthew Brousil to the blog today. Matthew is a graduate student at California Polytechnic State University and to find out more about him, check out his bio at the end of the post. 

When I meet someone new, they usually ask me what I do for a living and I tell them that I study redwood disturbance ecology. Their eyes will then open up wide and they will tell me either how they’ve always wanted to see the redwoods, or that when they did visit the redwoods, they couldn’t believe how huge they were. At this point I shift around uncomfortably and admit that while yes I do work in the redwoods, it isn’t in quite the same place as the massive old-growth stands of northern California that they might be imagining. Instead, I have been lucky in a different way. For the last two summers I have worked in the coastal redwood forests of Big Sur, California doing research for my master’s degree program. The redwoods are a bit smaller there, but the location is still incredible.

If the majority of graduate students in the natural sciences are anything like me, then the opportunity to do field or lab work with a unique species or in an interesting location was a big part of their decision to go to grad school. When I saw advertisements for a graduate research position studying the effects of fire disturbances on redwood forests, I jumped at the opportunity and put together my application pretty much overnight. Three years later, I spend most of my summer weekdays hiking from early morning until evening in the redwood forests of Big Sur to measure trees, collect soil samples, or take pictures of the redwood canopy to determine how much light reaches the forest floor where seedlings grow. Big Sur is a huge travel destination for tourists from around the world and my work lets me see many of the same trails and parks that tourists often visit, but in locations that are more ecologically sensitive and so not available for general public access.

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Me at one of Highway 1’s famous pullouts in the Big Sur area.

 

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Kara, a technician, and Devon, a volunteer, collecting soil samples from one of our research areas at Pfeiffer Big Sur State Park.

A hemispherical understory photo used to determine the amount of light reaching the forest floor.

A hemispherical understory photo used to determine the amount of light reaching the forest floor.                    Photo credit: Matt Terzes

 

 

One of the fantastic benefits of seeing Big Sur from *slightly* off the beaten path is that I have come to appreciate how dynamic and changing the forests and other ecosystems are along the coast. Having been a tourist in Big Sur myself, I know that the majestic redwood forests and picturesque scenery like McWay Falls inspire feelings of intense reverence and impermanence among such towering and grand sights.  And so they should.

Looking out over Highway 1 from a research area in Big Sur.

Looking out over Highway 1 from a research area in Big Sur.

Coast redwood trees in an area burned in 1985 and 1999.

Coast redwood trees in an area burned in 1985 and 1999.

Spending time off-trail for a couple of years in Big Sur, however, I now appreciate how often things really do change in the redwood forest. As locals are familiar with (and as news reports have reminded the rest of us this year), fire in the Santa Lucia mountain range is a common occurrence. Some of the sites where I do my research have experienced multiple fires in the past 30 years and the fire history for the coast redwood range shows similar patterns over longer periods of time (Lorimer et al. 2009). Large redwood trees often survive fires because of their thick bark and elevated branches, but smaller individuals are killed by tall flames yet remain standing for years afterward. Two years after a fire noticeable changes abound: thousands of sprouts and seedlings litter the forest floor around damaged trees, charred deer skeletons remain, slopes and trails become unstable terrain, and even the soil in some parts of the forest is stained an orange-brown color as a result of the fire. In areas where multiple fires occurred recently, some less fire-adapted tree species might be less common and smaller understory plants are absent from the forest floor.

Bottlebrush sprouting on redwood trees – the result of flames reaching the canopy of these trees.

Bottlebrush sprouting on redwood trees – the result of flames reaching the canopy of these trees.

 

 

 

 

Prolific sprouting at the base of redwood trees where fire has come through.

Prolific sprouting at the base of redwood trees where fire has come through.

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Since the Big Sur area has been fire-prone for thousands of years, the response to these fires is  cyclical, reminding us that change is a very natural part of healthy ecosystems. Winter rains lead plants in Big Sur to put on growth that becomes fuel later in the year, and many shrubs in the area are fire adapted. In some areas, lush plant growth even covers up the visual reminders of fire within a year or so. However, an increase in fire frequency due to climate change is expected in redwood and other temperate forests in the future. The goal of my research is to describe what could happen to redwood forests when fires overlap more frequently in time and space.

Doing fieldwork is one of the biggest draws for graduate students in ecology, and the chance to see behind the scenes of the coastal redwood forests in Big Sur is an opportunity that few students in my position would pass up. These experiences allow researchers like me to observe our ecosystems of study and to collect important data with which to test hypotheses. However, I think students also gain a lot in seeing how ecosystems like the redwood forest change over the course of the time it takes to complete our degrees!

But one thing that hasn’t changed in two years’ time is the uplifting feeling of a warm breeze carrying the smells of redwood needles and blackberries through the forest as I hike. With that kind of inspiration you can do just about anything – even write your thesis.

 

Matthew Brousil is a graduate student at California Polytechnic State University where he is working on his MSc studying coast redwood responses to fire disturbance. His first trip out to the field was in Patagonian Chile as an undergraduate, which sparked his current interests in coast redwood forest ecology. You can follow his work on Twitter through @mrbrousil.

 

 

 

How field biologists are like Olympians

Like a lot of people I am sure, I become very patriotic during the Olympics. I am even watching sports I never thought I would like but I find myself getting lost in the hype. Watching the Olympics while working on the blog has me comparing how field biologists are (maybe only slightly) similar to Olympians.

You may be thinking: “what could they possibly have in common?!” or “that is not a fair comparison!”, but hear me out. Don’t get me wrong, I appreciate the superhuman aspect of Olympic athletes; but if you think about it, there are some similarities.

You get to travel all over the world

Dispatches from around the worldAmong World Championships, PanAm games, Olympics, and other competitions in between, athletes are busy travelling around the world chasing the competitions. As you can see from our Dispatches from around the world map, field biologists are also fairly cosmopolitan.

Lots of preparation for a little time to perform

Olympians often train for years for their Olympic debut. Field biologists also have a lot of preparation to do before they set out for fieldwork. You have to chose your study

Fork-tailed storm-petrel in a burrow in the dirt

Knock knock

location, apply for permits, apply for funding, purchase (or find in the overflowing storage closet) equipment, practice your field techniques, and make sure you have a good idea of what type of data you want to collect. All this preparation is necessary for even a short field season such as a breeding season. If you are not prepared, you might not find the nesting sites or the birds may have already left!

 

 

Sometimes you have to perform in unpleasant conditions

Standing under the massive roots of a fallen tree

Can you ever be prepared enough for a ride on a tiny zodiac in the ocean?

Olympians in Rio this year have had to deal with many different conditions including an algae infested pool, sewage littered in the open water, and torrential downpour on the track. As a field biologist, it is no surprise that you will encounter some interesting weather, and likely conditions you were not prepared for. When I was going out to British Columbia for fieldwork, I expected it to be all wet and rainy. It turned out to be very warm and sunny, leaving me with only 2 t-shirts to cycle through (but lots of unused rain gear).

 

You are the best of the best; and yet still an amateur

The Olympic games are for non-professional athletes to compete. Similarly, students are the ones who are doing fieldwork to fulfil their degree so that they can become a “professional”. The expectation to do your best is evident during fieldwork as well – if you do not collect the right data you will not end up with the right results. This expectation leaves only dedicated and determined individuals to get the job done.

It looks deceivingly easy

I recently heard someone mention that a “normal” person should be included in Olympic events to remind the public that these athletes are in fact “superhuman”. The same could be said for field biologists. How hard could it be to sit in the sun on the beach all day to watch birds? If you take into account how many hours you spend sitting still in the sweltering heat, holding up your binoculars, with sand getting everywhere, it isn’t as easy as you may think.

There are also some similar events during the Olympics and fieldwork:

A tired selfie in the woods.

A field biologist’s hurdles.

-hurdles = climbing over fallen trees

-marathon running = marathon writing (workout for your brain when you return to the office)

-tennis = Cassin’s auklet, the seabird I studied for my Master’s degree, was known as a “tennis ball with wings”. Except this time you want them to get caught in the net!

What happens in the field stays in the field

As I have heard in interviews with Olympic athletes it sounds like this is true. They put everything they have into their events and leave it all out in the field. It is also a common saying among field biologists which is why we have it as our tagline for Dispatches from the Field. However, we have added “until now” as we would like this blog to be a place where field biologists can share all their stories that don’t make it into scientific papers.

Do you have what it takes?

It might be hot, but things are about to get even hotter

I love field work. It’s made my decade of post-secondary education so worth it. And just this last week, I started sampling my PhD field experiment for the last time. I’ve sampled this project in the month of August for 3 straight years now and this year it’s tougher than ever. I think there are at least a couple of reasons for the struggle this year. It’s my last field season and I don’t really know where I’m headed after this. I’ve been comfortable here for years, hanging out in my plots and counting my plants. Beyond the fear of the unknown and the comfort of the familiar, it’s also just stinking HOT. Our readers from Southern Ontario will know well that it’s been a brutal summer here with temperatures averaging the mid to high 30’s with the humidity for well over a month now. That, combined with the lack of rain (wait…what’s rain? It still rains nowadays???), has made sitting in these old abandoned fields slightly less enjoyable, by no means miserable, but certainly not wonderful.

Even though the struggle is real, I’ve persisted. Yesterday the sun was beating down so intensely on the back of my neck that I could have melted. On top of that, the humidity is so high that every piece of clothing no matter how loose clings to your body and of course there’s the deer flies. I sat there, on a bright orange milk crate, in the middle of an old farmer’s field and I thought to myself – why am I still here? I could have given up long ago. How am I persisting?

There’s a few reasons. First, I want to know the answers. I know I can’t answer my questions until I sit my butt down, and count my plants. And I do really, really want to know the answer, so I keep going. Second, I remind myself that it isn’t always like this. I’m not always going to be melting and drenched in sweat. There are lots of ups and downs in fieldwork and although, the heat might be a big downer, there’s still lots of neat things to see and experience that desk life just simply doesn’t permit. Finally, I love sharing the fieldwork experience with others. I love blogging about my experiences and I love giving our readers a true picture of what fieldwork is like. This is part of the experience, an experience most people do not get but would love to have. As field biologists we truly are the lucky ones.

Here at the blog we are even luckier because we get to share our stories with all of you, and because sharing those stories has resulted in so many new and interesting opportunities, collaborations and outreach experiences. Despite the heat Dispatches from the field has been keeping very busy this summer and have been sharing our fieldwork experiences with all kinds of people in all kinds of places. Back in May we went out to the Elbow Lake Environmental Education Centre and did a presentation for Youth. We told some fieldwork stories while also incorporating information about what field biology actually is and the various career opportunities that involve field research.

In June, Sarah took our display up to the QUBS Open House and promoted our blog to those in attendance. This is always such a fun opportunity to showcase the neat research and other endeavors associated with the station and also marked our 2 year anniversary!

In July we gave a talk at the QUBS weekly seminar series that was in collaboration with the Kingston Frontenac Public Library called “The Truth About Stories” where we told the many tales, trials and tribulations of fieldwork in an intimate cottage-esque environment at QUBS.

This week we just completed an interview with GradChat, a weekly radio show with CFRC about our blog. It was a great opportunity to showcase our own research and the blog! We will post a link to that when it’s available next week.

In the fall we are giving the inaugural Kingston Field Naturalists talk for the 2016-17 season and also will be involved with some events with Science Literacy Week so stay tuned and check back for more details about that!

As always thanks for reading and if you’re out in this heat doing fieldwork, stay cool and send us your stories!

Oh the places you can swim

One of my favourite things about fieldwork has nothing to do with the work itself.  For me, one of the best parts of being in the field is the chance to swim in natural water.

I’ve always loved the water, and taken every possible opportunity to swim in every available body of water, from pools to lakes to the ocean.  No matter where I’m swimming, the feeling of moving through water is wonderful; for a klutz like me, feeling graceful and fluid is a welcome change.  But as much as I love pools, they just don’t compare to swimming outside in natural water, surrounded by the green of trees, the pink and grey of rocks, and the blue of the sky.

I’m at my happiest when I’m floating on my back in a lake on a hot summer day, staring up at a blue sky scattered with clouds, and letting the water bob me up and down.  And there’s no better way to end a day in the field than by submerging yourself in water and feeling the stress, frustration, and sweat of a hard day’s work wash away.

Swimming is such an integral part of fieldwork for me that I’ve gone to some rather extreme lengths to get in my field swim.  For example, during some recent fieldwork in Manitoba, I decided that my field experience would not be complete without a swim in Lake Winnipeg.  Never mind that the weather was unseasonably cool, or that we never got back from the field before dinnertime…the lake was there, which meant that I had to swim in it.

I quickly discovered several…interesting…aspects of Lake Winnipeg that make swimming an adventure.  For one thing, the water is an opaque muddy brown, so dark that you can’t see your own feet when submerged.  It’s a bizarre feeling, jumping into water with absolutely no idea what else might be in there, right below your feet.

But for me, the real problem was the horse flies, which turned swimming in the lake into an extreme sport.  Each time I went swimming, no sooner had I ducked my head under, than one of these huge biting flies would come buzzing out of nowhere.  Usually she would bring at least one friend, and the two of them would circle my head in an ecstasy of excitement about having found a warm-blooded creature in the midst of all that water.

Swimming then became a race between me and the demon flies, as they tried their best to get their pound of flesh and I tried my best to thwart them.  As they circled closer to my head, honing in on me, I would duck under the water and swim for as long as I could hold my breath, then pop up and enjoy the blissful silence – which would inevitably be broken within milliseconds by a frantic buzz as the flies noticed me again.  When I got out of breath, I’d flip onto my back, leaving just my face showing above the water.  The flies would counter by landing on my forehead and nose, forcing me to swat wildly at them.  In the end, I managed to avoid getting bitten, but every swim was frantic and punctuated with episodes of ungainly flailing.  I’m sure I gave people on the shore a good laugh – but the swim was still worth it.

The inviting (?) waters of Lake Winnipeg

The inviting (?) waters of Lake Winnipeg

While swimming in Lake Winnipeg was definitely an adventure, the lake itself didn’t feel all that different from the Canadian Shield lakes I’m used to.  But sometimes, in the course of fieldwork, I’ve resorted to swimming in some pretty odd places.  Take, for example, my field season in the Dominican Republic.  You would think the swimming opportunities would be boundless on an island renowned for its beach resorts.  However, when you’re up in the mountains, hundreds of kilometers from the nearest beach, you have to make do with what you have.  In our case, that was the little canal that ran past our camp and down into the nearby village.

Canal or lap pool? Beggers can't be choosers!

Canal or lap pool? Beggers can’t be choosers!

While doing ‘laundry’ (i.e. making a valiant attempt to rinse at least the top layer of dirt out of my field clothes) in this canal one day, I realized that it could, in theory, be used as a lap pool.  The current was strong, the water was cool and clear, and the canal was just wide enough for a comfortable breast stroke.  So as soon as we’d hung the laundry up to dry, I decided to try it.

At first, I thought I’d found the perfect solution to satisfy my swim cravings: the canal was refreshing in the tropical heat, and while the current was challenging (I certainly couldn’t float on my back for any length of time without being pushed downhill towards the village), it was great exercise and lots of fun.

DR 1 039

The after-effects of canal swimming…

It wasn’t until I got out of the water that I noticed my arm was just a bit itchy.  The itch built over the next few hours…until the back of my arm was swollen and covered in welts.  When I mentioned the problem to the family that lived at the camp, they managed to convey to me, using a mixture of Spanish and English, that the canal was a favourite spot for many things – including a very tiny, but very effective, biting bug.

So my first canal swim was also my last canal swim, and I resigned myself to a swim-free field season.  However, the dry days were more than made up for when we took a brief trip to the closest beach (an ~8 hour drive away), and I got my first chance to swim in the Caribbean sea.

Now *that's* more like it... the Caribbean sea near Oviedo.

Now *that’s* more like it… the Caribbean sea near Oviedo.

But no matter how many fantastic (and…er…interesting) places I’ve gone swimming in the field, none of them can top swimming at the very first place I did fieldwork, the Queen’s University Biological Station.  Down a path worn by generations of feet, out of sight from the main station road, is a slightly ramshackle metal diving board hanging over a quiet stretch of Opinicon Lake.  During the day, the water is warm and clear, making it easy to see the group of sunfish that hang out under the diving board, and the shore is bordered by thick trees and the occasional glimpse of grey rock.  At night, you can float on your back, stare up at the stars and count the passing fireflies.  It’s a site of laughter, conversation, and splashes, but also a site for quiet contemplation.  Most of all, it’s a place where you can relax and let the lake water do its quiet work to wash your worries away.IMG_2370

Lost lake entrances and the drunken bathtub

This week we welcome Cassandra Cummings to share her adventures in New York State in the gorgeous Adirondacks.

Some of the best hiking on the Canadian Shield can be found in the Adirondacks, NY, and I was lucky enough to do 3 summers of field work there.  The Adirondacks are an old mountain range that makes up 20% of New York state, and contains more than 3,000 freshwater lakes.  They were hit hard in the 80’s and 90’s by acid rain, and have remained an interesting study site ever since.

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Examining a sediment core

Taking a sediment core

Since the Adirondacks are somewhat isolated, there is an absence of long-term monitoring data.  This is where my field of study, paleolimnology, comes in handy.  Paleolimnology uses the physical, chemical, and biological characteristics in lake sediment cores to infer their environmental histories.  For my fieldwork, I collected sediment cores from 30 lakes throughout the Adirondacks.  Collecting a sediment core is similar to putting a straw in a cup of water and putting your thumb on the top; when you pull it out, you take the water with you.

In my cores, I examined microscopic algal remains called diatoms.  These algal remains are abundant and can survive in the sediments for millennia.  They are also incredibly specious and can survive in a wide range of conditions.  Their diversity is part of what makes them such a useful indicator species: by determining which species used to exist in a lake, you can infer what the conditions of the lake were like.

Diatoms

We may not have been after forest creatures, but they did manage to keep things interesting!  We got to see loons attempting to fly (it takes an entire lake’s distance just for them to make it out of the water!), a snake catch a frog, and a just-out-of-sight bear.  Twice, our hiking paths were flooded by beavers.  The first time, we were hiking and came across a surprise pond.  At first we thought it was our study site, but it was way too shallow.  Then we assumed we lost the path and spent half an hour looking for it, before we saw the next marker across the pond.  In the dingyWe tried to go around it, but decided the easiest way would be to cross it.  We blew up our inflatable dingy, and two of us crossed the pond with half our stuff.  We thought we were well on our way to defeating those rascally beavers, until I was dropped across the pond with the packs and my field mate turned back to pick up our third hiker.  Turns out it’s hard to cross a pond with one person using one oar in an inflatable dinghy.  It moves less in a straight line, and rotates more side to side.  She eventually made it back, but it moved like a drunken bathtub in the meantime!

In the canoe

Fortunately, the second time beavers flooded the path we were warned in advance.  We brought a canoe, and could all make it in one go!

 

 

putting the canoe in the truck

The canoe almost fit in the truck.

 

swollen right handInjuries on our field trips were kept to a minimum.  But when we did have one, it was almost always mine!  Our first day out the second summer, on a wide, flat path, I managed to twist my ankle and end up out of commission for a week.  I also found out the hard way that I’m allergic to deer fly bites.  Good thing I’m right handed…

When field work ended, we got back to the lab to begin the long, tedious process of diatom identification.  After enumerating the diatoms at the top and bottom of the core, we were able to infer how some aspects of the lakes had changed from the 1850’s to present. Lakes are warming up faster than they used to each year, leading to changes in the way a lake stratifies (a warmer, less dense layer on top of a colder, denser layer below).  Ice is melting earlier in the spring, and forming later in autumn.  These changes caused corresponding changes in which diatom species were most successful in a lake, with diatoms that sink slowly becoming more abundant.

My project gave insight into the extent of ecological change in algal communities  that could be attributed to a ‘climate’ effect.  By understanding how climate change affects lakes, we can begin to understand and interpret changes from lakes that are recovering from multiple stressors.

lake view

 

Cassandra Cummings is a 2nd year masters student at UBC, doing a masters in Environmental Planning.  In 2014, she completed her masters in biology at Queen’s University.  She has hiked in the Muskokas, Rocky Mountains, and Central America, but the Adirondacks are still some of her favourite!  She is passionate about the environment, enjoys being outdoors and loves to dance.

Dirt

I just returned to Kingston, Ontario from a whirlwind three weeks of travelling. I spent awhile in Colorado, mostly Colorado Springs and Denver, and then went on to present my research at the Canadian Society for Ecology and Evolution’s annual conference in St. John’s, Newfoundland. It was a mix of scorching heat and nipping cold, desert-like brush and lush green rolling hills, Rocky Mountains and coastal cliffs. It was amazing.

It wasn’t all just fun and games though. At the conference in St. John’s I presented one of the projects that I’ve been collecting data for 2 years for. I was interested in the role that body size played in predicting the abundance of seeds in the seed bank.  So to answer this question, I went out and collected soil cores, which is a fancy way of saying I collected dirt.

I hadn’t put much thought into dirt before. I played with it as a kid, my brother used to eat it, it is brown, and plants grow in it. Even as a plant biologist I really hadn’t thought too much about it. After I started this experiment, I quickly realized that dirt was more than ‘just dirt’.

Early in April 2014 I collected my first set of soil cores. It was surprisingly laborious work with lots of bending and pulling to get 4 samples from each of 200 plots. Keep in mind that it was still teetering around 0 degrees C and doing things like opening Ziploc bags with mittens on is next to impossible. Timing here was critical because as soon as the first seeds germinated in that field, we would be too late. At each plot, 4 samples were taken and placed in the same plastic bag. They were then stored temporarily in a fridge at 4 degrees C until they could be processed.

cllecting soil core

Collecting soil cores

Processing these soil cores was such a neat experience and it made me realize just how neat (and also cute and sometimes terrifying) dirt really is. The cores were all so different. Some had soft, loamy soil that fell apart and crumbled in between your fingers. Others were like taking a piece of freshly made fudge and squeezing it between your fingers. We would sort through the dirt and pull out rhizomes and pieces of roots, gently brush the dirt off and throw them away. We pulled out hundreds if not thousands of worms from the cores, as well as larva, dead insects and even sometimes bones of what appeared to be voles or other small mammals. On more than one occasion, the bag housed an army of ants, which then proceeded to attack everyone and everything at the table. Those bags were the ones I let the minions take care of…*gross*.

soil core

Soil core – Note: the worm trying to escape

bagging cores

Bagging more soil cores

My favourite discovery was a small grey tree frog. I opened a Ziploc bag, took out a core, and as the dirt fell out onto the tray, a small tree frog hopped onto the table. As it came to it was just as confused as I was and attempted to hop away and right off the table (of course we released him somewhere a bit more suitable than the halls of the Biology building).

frog

Our new friend who lived to tell a pretty cool story

After the cores were all sorted we emptied each bag into a small plastic tray, and put it up in the Phytotron at Queen’s. We watered them and monitored them regularly, and what happened was pretty cool. Seeds from close to 60 species germinated and grew into tiny seedlings in those trays. Sometimes you would even see hundreds of individuals of different species coming up in one 4 x 6 inch tray.

phytotron plants

All the seedlings that grew in the Phytotron from seeds in the seed bank

This project, fieldwork, greenhouse work, and all, has remained one of my favourites I’ve done to date. Not for its simplicity, or low maintenance nature, but because it made me think about dirt, and dirt deserves a lot more credit than it gets because damn, it’s pretty neat.

Studying guppies in Trinidad

For National Fishing Week, Dispatches from the Field welcomes Tim Hain, a biologist at the University of Western Ontario to tell us about his fieldwork studying the not-so-fancy-looking (but very cool for evolutionary studies) guppies in Trinidad. To find out more about Tim and his fieldwork stores, check out the end of this blog for a link to a book he recently published!

Many North Americans have heard of guppies – perhaps because they or a friend had guppies as pets, perhaps because they have watched Bubble Guppies on television. Aquarium hobbyists have an enthusiasm for guppies because these fish have natural variation in colouration and fin size or shape that breeders have exploited to develop many different beautiful strains with descriptive names like tuxedo, sunrise, mosaic, snakeskin, or swordtail. Although “guppies” have name recognition with the public, many people do not realize that these little fish are a favourite among researchers in evolutionary ecology. In fact, guppies are one of the best vertebrate species for studying evolution in the wild, particularly on the island of Trinidad in the West Indies. Because guppies have short generation times and waterfall barriers that restrict migration, there is variation in behaviour, life history, physiology, and appearance among populations that can often be attributed to variation in the local predator community.

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Image 2The classic story is that guppies below waterfalls are subjected to predation by large vision-oriented predators, so male guppies in these populations tend to be cryptic in colour to avoid being eaten.Image 3

 

 

 

 

Above waterfalls, the predators are either smaller and cannot eat adult guppies Image 4or eat using tactile or chemical signals,Image 5

so male guppies from these populations are free to evolve conspicuous bright colours to attract females.Image 6Many evolution students will have heard all about this. But “science-world famous” is very different from “world famous.”

 

 

In fact, most people do not know how important these insignificant-looking fish are. When I first went to Trinidad in 2006 as a Ph.D. student, I had been studying guppies for three years. At its most fanciful, my imagination pictured monuments to guppies at important sites around the country.

Of course, I did not truly expect to find statues of guppies, but I was amazed by how common guppies were in the country. My first ‘wild’ guppy sighting was in a sewer along the major east-west road, and this was not unusual.Image 7 In fact, they are so common that many locals were surprised that someone would travel from Canada to study them. In some locations where I collected guppies, I would attract a small crowd. Because I neither looked or sounded like I was from around there, local people would ask me what I was doing. One middle-aged Trinidadian that I spoke to was confused when I mentioned guppies, but when I described them, he said “Oh, you mean canalfish.” In Trinidad, guppies have this common name because they are frequently found in sewers and ditches alongside roads. Several times I used this name with Trinidadians to refer to guppies, and they knew what I meant.

Because female guppies give birth to live young, a single pregnant female can establish a population. This makes guppies master colonizers, and I saw them in a huge range of environments. Image 8The best-studied guppies are native to the Northern Range of forested mountains, where waterfalls break up narrow streams, but they are also founder in wider, dirtier rivers and some unique geographical features, like Pitch Lake in the southern part of the country.

Image 9a

My mother and a guide.

Pitch Lake was formed when pitch – a resin once used for waterproofing ships – bubbled out of the ground and now covers 40 hectares of area . It resembles a naturally-formed parking lot, but without lines and full of fissures that give the tarmac area structure. Rain filled these fissures, and guppies have found their way to the lake and become established. The unusual water chemistry of Pitch Lake and the black substrate (leading to high water temperatures) means that it is very difficult to rear these guppies in the lab.

One environment where I did not find guppies was in the brackish estuaries along the northern coast. Guppies can tolerate light saline environments, but in one tea-coloured estuary that I visited, I instead found the congenic Poecilia picta fish. Image 10The low visibility in the water of that river might explain two unusual observations I made: low colouration of P. picta males, and transparent bodies of their predator, a prawn.
Image 11

 

Transparent bodies are also found in deep-sea fish, which live in low-light (or no-light) environments: an interesting example of convergent evolution.

Perhaps the reason why guppies are such an appealing textbook example of evolution is in how intuitive and simple the explanation is: the same geographical barriers that restrict predator presence also restrict gene flow, and predation as a selection pressure drives trait differentiation. Guppy researchers know that the story is a little more complex than that, but these wrinkles in the story seldom make it into textbooks. So, I was left to independently discover these things for myself.

One variation on the story is that waterfalls are not the only feature that restrict large predators. For example, I found one ‘low predation’ environment located between two ‘high predation’ environments because the water in one stretch of the river was too shallow for the larger predators to enter. Male guppies in this stretch were more colourful than males I found upstream.Image 13Image 12

A second under-discussed variation on the story is the presence of avian predators. I often saw striated herons or little egrets walking alongside narrow streams, looking for guppies to eat. I also saw or heard kingfishers around my collection sites. Image 14These birds were skittish and difficult to photograph in the act of feeding, but their intention was clear. What is less clear is if they exert a selection pressures on guppies to be more cryptic in colour, or if their feeding habits are random with respect to colour. I do think that avian predators are important to guppy evolution – I suspect that guppies colonize new environments by escaping these flying predators after being given a short trip.

My fieldwork in Trinidad taught me many things about guppy evolution that I could not have learned from a textbook. Who knew that such small and common fish could be so interesting?!

Tim Hain is a biologist at the University of Western Ontario in London. He completed his PhD on kin recognition and multiple mating in guppies and bluegill sunfish, and he did his fieldwork in Trinidad and at the Queen’s University Biological Station. His first trip to Trinidad was for eight months, and he recently published his memoirs (Fieldwork: Stories from Trinidad) of his time living in the country on Amazon. Tim currently teaches at UWO. You can follow him on Twitter (@tjahain).