Water

Today’s Photography 101 topic is practically made for me: water!  Here’s my choice of photo:

  
This is a waterfall on the same creek I shared yesterday, in Sabino Canyon just outside Tucson, AZ. I share it because it’s water, but also bacause it illustrates something important in stream habitats, a natural barrier.  This creek is full of crayfish.  Crayfish don’t belong in Arizona and every species you can find there is invasive.  They compete with native species in the state’s streams and alter the habitats as they burrow into streambeds.  I always hated coming across crayfish when I was working in streams in Arizona as the streams where you found them were often highly impaired.

However, a lot of aquatic species have a hard time moving further upstream once they encounter a natural barrier like a waterfall.  In Arizona, waterfalls are often the furthest upstream you’ll find invasive species like crayfish.  In fact, in this particular stream, you find crayfish up to a point called Anderson Dam (a little further upstream from this waterfall), but not any further upstream.  That also means that some species are only found above the dam, such as a cool species of damselfly called the Sabino dancer.  The species is found outside of this canyon in a few other places nearby, but this is one of the best places to see them.

Waterfalls are beautiful, but also important dividers in stream systems.  That makes them both beautiful AND interesting to me, so I’m always happy to come across a waterfall.

I am going to be traveling tomorrow, so probably won’t be able to get a post up until Friday, but I’m going to keep at it for a while.  Look for another new post coming soon!

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth.

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The Power of Water Moving Downhill

A while back, I wrote about the microhabitats in the stream where I work and mentioned how the stream is missing some insects I would expect to see in this area.  Most significantly, it’s missing the swimmers.  I haven’t seen a single swimmer in the creek, and I’ve gone looking for insects dozens of times.  The absence of swimmers is curious.  To be missing things like the predaceous diving beetles and the water scavenger beetles…  Well, that just doesn’t happen!  That suggests that there is something happening in the stream that prevents those groups of insects from establishing themselves, and it presents a nice little puzzle to solve scientifically.  With the help of a group of high schoolers and a couple interns, I’ve been monitoring several characteristics of the creek.  The water quality isn’t bad, so it is unlikely to blame for the lack of swimmers.  However, there is another, more likely explanation: flooding.

The Prairie Ridge creek is small, but it drains a large part of the surrounding area.  Let’s take a look at a map for a moment:

Map of Prairie Ridge

A lot of the land to the right of or below Prairie Ridge (outlined in white) on the map drains into our creek.  Everything that is dirt in the center of the map is currently covered in either asphalt or buildings, neither of which absorbs water well.  So, every time it rains, the water runs downhill and ends up in our creek.  The result: we get a big pulse of water entering the creek with every rain event.  Small rain events cause a bump in the stream flow, just enough to make everything look muddy for a few hours, maybe overnight:

muddy creek

Muddy creek

Significant rain events, however, can cause the water to rise so quickly and the flow to blast downstream so hard that it carves new channels, rips banks down, pulls trees out by the roots, and washes it all downstream.  It’s impressive to watch the water in that creek during long and/or heavy rains!  It flows hard and very fast.

Now imagine a little beetle in the stream.  Heck, let’s imagine a big beetle, one of the Cybister predaceous diving beetles that are over an inch long and strong swimmers.  It’s there minding its business, swimming around a deep pool and hunting for food, when it starts to rain.  What do you think happens to that beetle when a huge pulse of water suddenly washes into the stream?  When there’s enough water to rip whole sections of the bank away?:

bank collapse

Bank collapse

The substrate of this stream is mostly sand and small cobbles with few larger rocks.  When it rains hard and you get a big pulse of water flowing downstream, that water picks up the lightweight substrates in the stream and washes them away.  That means that not only is there water flowing downstream very quickly and powerfully, but that it’s churning up sand and rocks as it goes.  Now think about that beetle again.  It’s not built to hold on during floods.  It’s got legs adapted for swimming, not clinging, and probably couldn’t hold on if it tried.  It’s left exposed, so down the stream it goes!  It may be carried miles downstream, assuming that it manages to escape being sandblasted by the churning, roiling mix of water and sand along the way.

We do find some insects in the creek, and they tell an important story.  There are caddisflies, tightly attached to the underside of heavy rocks.  Those rocks will move if the water is flowing hard enough, but for the most part they stay in place.  If you’re a small insect in a stream, living under one of those rocks is smart.  We also have calopterygid damselflies (the jewelwings) lurking in the root mass on the upper left side of this photo:

Prairie Ridge stream

Prairie Ridge stream, showing root mass

More of those roots are exposed every time a flood moves down the creek and the tree will likely fall over one day, but for now it provides a safe haven from floods for clinging insects like damselflies.  I imagine that they hold on for dear life in floods, hoping they won’t be swept downstream. 

We’ve found a few black fly larvae in our samples, insects that use silk to secure themselves to the tops of rocks.  In good black fly habitat, you might see thousands of them coating the rocks in huge mats.  Our stream is not good black fly habitat because we’ve only found a few black flies, but that’s not surprising.  Sitting on top of a rock, even a big, stable rock, isn’t necessarily the safest place to be in a flood.  Imagine standing on top of a house, or clinging to a tall tree, as a huge tornado is headed your way.  You can hold on as tightly as you can, but there’s still a good chance you’ll be knocked from your perch or mortally injured if something big hits you as the tornado engulfs you.

We find insects in the protected areas of the stream, but they are conspicuously absent from other areas.  The pooled areas are wholly devoid of insects, which leads to other interesting questions.  Are the insects colonizing the creek, only to be washed downstream in the first big rain?  Are they colonizing, then starving because there isn’t enough food available?  Or are they actively avoiding colonizing this creek altogether?  I hope someday I’ll be able to test these questions, but for now they’re merely interesting questions to ponder.

With the ease and speed with which the creek rises and falls, it’s little wonder that it’s missing a few groups of insects!  I’ll write about this project again when we have more concrete evidence to explain what’s happening in the stream, but for now I leave you with this thought: water moving downhill is an amazing, terrible, and awe-inspiring force of nature.  It carves canyons and carries with it the power of life and death.  There are few things water can’t move when there’s enough of it, so give it some respect!  You won’t be sorry you did.

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth

Some Thoughts on Endangered Aquatic Species

Arivaipa Creek looking toward the canyon

Arivaipa Creek

Warning: This post will not be my usual happy, hooray for nature type post.  This one deals with a serious issue and may be considered depressing to some readers. Consider yourself warned.

The Zoological Society of London recently released a publication called Priceless or Worthless?  The World’s Most Threatened Species.  In spite of the fact that I absolutely hate the title (I don’t like to think of any species as worthless, no matter how few of them are left), I was eager to look through the document to see what sorts of invertebrates their list contained.  I was happy to see that several insects and other arthropods are featured, including a few damselflies, a few butterflies, a spider, a crab, a cricket, a bee.  I think it’s fantastic that so many invertebrates made the list as it means that people out  there care whether these animals live or disappear forever, and that sort of attention and love is rarely bestowed on the spineless creatures of our planet.  It’s sad that these creatures made the list in the first place, but it also means that they will get a lot of attention, and that’s a good thing.  Insects and their relatives get far too little attention when it comes to endangered and threatened species lists and it’s high time we started paying more attention to them.

bonytail fish

Bonytail chub, and endangered native fish in Arizona

Looking at the list as a whole, however, got me thinking.  Yes, there are several insects on the list, but I noticed something else: there are a lot freshwater species  listed overall.  This wasn’t especially surprising as I know how specialized aquatic organisms can be, how they can be so incredibly picky about where they live that it puts them at risk when anything in their environment changes.  For example, amphibians have been on the decline for years.  Scientists have variously pointed to habitat destruction, pollution of aquatic habitats, increased UV radiation passing through a thinner ozone layer, climate change, and the recent epidemic of chytrid fungus throughout most of the world as explanations for the decline.  In some areas, a combination of these factors have even led to extinctions of amphibian species and may lead to more in the future.    Amphibians are incredibly sensitive to changes in their environments, and that’s not really a good trait to have in a changing world.

Tree frog

Tree frog – adorable!

But frogs are big, showy animals that a lot of people like.  Many aquatic insects are likely similarly sensitive to changes in their environments, but we know so little about them we can’t even describe the distribution of many species with any sort of accuracy.  One species of riffle beetle was described from specimens found only in a single stream in the Chiricahua Mountains of southern Arizona, but is that really the only place they live?  Is a population still found there?  And what about the big Horseshoe 2 fire there two summers ago that burned a huge part of the mountain range?  Riffle beetles generally require clear, cool, flowing water to survive and that one population was likely incapable of surviving ash flows.  Has that species gone extinct?  Does anyone know?

Priceless or Worthless also includes an 8-page list of species that have already gone extinct.  Among the relatively small handful of insects that are known to have disappeared (and there are half as many insect species listed as birds, in spite of being a much more diverse group), you see the usual trends: mostly butterflies and moths with some beetles and several aquatic insects.  The latter include caddisflies, mayflies, and stoneflies, insects that are generally sensitive to pollution, habitat loss, and other changes in their habitats.  However, that list includes only species that we know have gone extinct.  How many insect species have disappeared without our even noticing?  I think we’d be lucky to observe the disappearance of most species.  And then there are the untold millions of insects that we haven’t even cataloged and named.  There are so many insects out there that it’s simply impossible to monitor them all and we know very, very little about most species.  That, combined with the public relations problems that insects typically face, means that insects are often ignored when endangered species lists are compiled.  It is likely that countless species have gone extinct without ever even drawing our attention.

Glossosomatid caddisfly

Glossosomatid caddisfly

Looking through the list of the 100 most threatened animals and seeing some aquatic insects and other aquatic organisms there gives me hope that people do care about these species and are working to protect them.  That’s a step in the right direction.  But are we going to be able to save them?  Consider this: the human population topped 7 billion people about a year ago.  We added 1 billion people between 1999 and 2011.  That’s 1 BILLION more people who needed places to live.  That’s 1 BILLION people who needed water to drink.  That’s 1 BILLION people who depended on crops that require watering.  That’s 1 BILLION people who produced more waste, a lot of which ended up in our waterways.  Many of the world’s great rivers are already so badly polluted that they are becoming virtually unusable by humans (the Yangtze River, for instance).  Many of our rivers have seen severely depressed flow over the last 100 years such that even mighty rivers like the Colorado River, once a lush and vibrant river along its entire length from the Colorado Rockies to the Gulf of California, only rarely reach the ocean now.  We humans are in direct competition with aquatic plants, animals, and other organisms for aquatic resources.  When it comes down to a choice between us or them, does that rare caddisfly living in one stretch of one mountain stream have any chance as the human need for water advances into its habitat?

caddisflies

Caddisfly adults, aquatic as larvae

If you haven’t noticed from my writing on this blog, I love this planet.  I try to stay positive about things, think that we can make things better.  For the most part I focus on all the positive, wonderful things in our world.  But, I also recognize that my favorite insects, the ones that live in my favorite habitats, really are at risk of extinction.  I know I would gladly give up a golf course to save a caddisfly species when both required the water.  I would gladly forego a lush, green lawn to ensure that my unborn children have a chance to see a rare stonefly in a local stream.  I like to believe that a lot of people would do the same if they recognized the risk these animals face (that’s one of the seven impediments to invertebrate conservation I discussed back in January).  However, if we ever have to decide between getting enough water to drink and saving that caddisfly or that rare stonefly, it’s unlikely to end well for the insects.

Sunset at Los Fresnos

Sunset over lake at Los Fresnos

So what can I do about it?  Well, I’m going to keep blogging for starters.  Very few non-scientists even know aquatic insects exist, so getting information about aquatic species out there into the world is a good thing to do.  I can educate people through my job and encourage people in my area to conserve water.  I will continue photographing aquatic insects because I believe people are less inclined to let a species go extinct if they can attach a face to it than if it remains a total stranger.  I can continue to make changes in my own life to help alleviate some of the stress on our aquatic habitats.  I truly believe we can coexist with the species around us with proper education, planning, and awareness of how our actions impact our world.  And indeed, Priceless or Worthless ends on a similar note, describing some conservation successes, species that have recovered after nearly going extinct.  There aren’t any insects on that list, but there have been some successes in saving butterfly and dragonfly populations from extinction over the last few years that weren’t featured.  It’s my hope that someday I will see an insect on that conservation success list – and maybe it will even be aquatic.

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth

Well-Nigh Wordless Wednesday: Lake Waccamaw

The day I got to see all the carnivorous plants in North Carolina’s Green Swamp, I also got to go to Lake Waccamaw.  It’s a great place!  It’s a bay lake (that means it’s surrounded by bay plants) and it’s incredibly shallow, 11 feet at the deepest point.  Still, it’s huge by Arizona’s standards, and it was a glorious place to swim, seine for native fishes, and survey the native freshwater mussels after a hot trip through the swamp:

Lake Waccamaw

Lake Waccamaw

I especially liked it because there were tons of dragonflies flying along the shores, zipping along through all that vegetation.  Bet you didn’t see that coming, did you?  :)

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth

Prairie Ridge Ecostation’s Aquatic Habitats

You all know that I am in love with water.  That’s one thing my new home state of North Carolina has in abundance!  There’s water in the air, water falling from the sky on a fairly regular basis (though I’m told it’s been a particularly rainy summer so far), and there are aquatic habitats practically everywhere I turn.  I used to have to drive several miles in Tucson to get to the closest water, a city park with couple of tiny ponds filled with reclaimed water, but now I’ve got 4 sizable “ponds” mere blocks from where I live and the Neuse River is less than a 1/4 mile away.  The idea of getting a boat has crept into my mind more than once and the thought isn’t completely laughable anymore.  I could actually carry a lightweight craft to the nearest body of water!  I absolutely love it.

The nature center where I’m working also has water.  Let me take you on a brief tour of the aquatic habitats.  I mentioned the little water garden in the demonstration garden last week:

Water Garden

Water garden

It’s small, but I still enjoy poking around in there to see what I can find.  I’ve always loved water lilies, and the carnivorous bladderworts fascinate me:

bladderwort

Bladderwort

I hope I can see one trap an insect sometime!  There is also a little bog garden in the demonstration garden that is filled with plants capable of surviving in saturated soils for at least some length of time.  But these two aquatic areas are nothing compared to the other aquatic habitats at the ecostation.  This is the pond:

Prairie Ridge pond

Prairie Ridge pond, in the rain

It’s not entirely natural and has a man-made earthen dam at the lower end, but it is fed by rainwater coming off the prairie.  I think it’s beautiful!  There aren’t any fish in the pond (yet at least), so the top predators in the pond are snakes and aquatic insects.  The pond is also where you find the biggest diversity of dragonflies on the Prairie Ridge grounds.  There are a lot of dragonflies there, including the comet darners:

comet darner female

Comet darner female

This individual was caught by a mist net that was set up to trap birds so that they could be banded and released.  Comet darners are widespread in the eastern US but aren’t especially common in any given place.  I feel fortunate to have seen both males and this stunning female at a pond that is so close that I can visit it on a quick break from work.  I find myself down there often!

This is also on the grounds:

Prairie Ridge stream

Prairie Ridge stream

This stream is absolutely beautiful and winds its way through the wooded area of the property.  The water is clear and I’m told that the quality is quite high. However, there is an Army National Guard base across the street and all the water from the extensive parking lots there flows into this stream.  The result is it floods quite frequently and there is a lot of visible erosion:

Prairie Ridge stream

Prairie Ridge stream showing erosion of the banks

I got to see a bit of flooding firsthand last week.  I visited the stream briefly to take the photos above and then revisited the same spot three hours later to help another entomologist set up some light traps for moths.  It had started raining in the interim and the change in flow in the stream was quite impressive! All that flooding unfortunately means there aren’t all that many aquatic insects in the stream, but I’m still looking forward to poking around in the water to see what I can find.  Might actually be a fun place to determine how flooding impacts aquatic insect recolonization in a humid region.  The moth traps turned up quite a variety of predaceous diving beetles, creeping water beetles, and other aquatic insects, so there’s got to be at least some good stuff in there!

Overall, I feel very lucky to be working in such a beautiful place.  My new coworkers have seen dragonfly swarms over the prairie, and I’m living less than 2 hours from one very heavily traveled route on the migratory route for green darners, so it’s a good place for my dragonfly research.  I can pop down to the pond in minutes and check up on what’s there easily, including the giant water bugs.  The stream is absolutely gorgeous and there are bugs simply everywhere.  Honestly, I couldn’t have picked a better place to work.  I hope you all enjoy hearing about my adventures there!

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Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com

Well-Nigh Wordless Wednesday: Tinaja

Many streams in southern Arizona are either ephemeral (they only flow a small part of the year) or intermittent (the water is disjointed during dry seasons with pools of water separated by dry stretches, often connected by underground flow).  Many of those same streams are also partly or completely lined with bedrock, a solid layer of rock over which the water flows.  In bedrock-lined streams, the water doesn’t soak into the ground during dry periods and instead sits on top of the rocks as shrinking pools:

Madera pool

Tinaja in Madera Canyon

These pools are called tinajas (tih-NAH-hahs) and are very important to many desert aquatic insects.  In fact, they are often the only reason many insects survive until the rains return and flow is restored in the stream.  They are absolutely full of life!

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth

Well-Nigh Wordless Wednesday: Flood!

I sampled aquatic insects for two years as part of a research study for the National Park Service, but the sampling period occurred during a drought and there was rarely water in the creek.  A month after we stopped sampling, a massive flood ripped through the creek:

Rincon Creek after the flood

Rincon Creek, after the flood

This flood uprooted hundred year old trees (notice all the exposed tree roots to the lower left), significantly widened and straightened the creekbed, and wiped out the USGS stream gauge entirely.  Impressive, though it would have been nice for this to happen during our study so there was actually some water…  :)

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Unless otherwise stated, all text, images, and video are copyright © 2011 DragonflyWoman.wordpress.com