Archive for the ‘Ecology’ Category

Yellowstone River Oil Spill- Redeux

Tuesday, August 23rd, 2011

Well, you may have noticed that I have not said anything about the Yellowstone River Oil Spill since our original entry. Yet, in truth, we have been busily working on the project in-house.  The experience has not been all-together positive; quite the contrary. This entry deals with how the public loses because of bureaucracy; bureaucracy of the corporate breed, not the  governmental red tape I’d expected.

After the oil spill, we contacted Montana Department of Environmental Quality (MT DEQ) for information, they put us in contact with Montana Fish Wildlife and Parks, who deferred us to ExxonMoble’s contact, who put us in touch with a consultant. We discussed my qualifications and my previous work and he reckoned they could use me and my team for the aquatic insect assessments to describe the impact and the recovery of the Yellowstone ecosystem. He sent me an email about once a week to say, they were still trying to bring us on board. After several weeks, he said I better get an OSHA hazardous materials certification and that there was no way around the requirement if I want to work on the Yellowstone River. Several hundred dollars and 3 working-days later (per trainee), we completed the certification.  I informed the contact that we had completed OSHA training as required and didn’t hear back from him for over a week. He said, sorry, “Sorry don’t think its going to work out.” I wrote him a scathing letter; which he apparently passes along to ARCADIS (Exxon’s Primary firm for everything), the next thing I know, I received an 158-page listing of ExxonMoble’s contracting requirements and several 6-9 page contract specifics and insurance requirements.   Again, these were corporate regulations, not governmental regulations.  I had my insurance agent looking into the extra coverages required and it was apparent that it was going to be very costly to bring our $2-million insurance coverage up to the “required” $9-million; just to collect insects by the riverside.

We were working on finalizing their insurance needs when I recieved the following note (today).

“Brett,
It looks like the clock has run out. We have had to mobilize a small field effort to obtain representative macroinvertebrate samples from the spill area. We needed to get out there before fall influenced the life stages we are sampling. Apologies to you if I was in any way misleading regarding your potential role, but we simply did not comprehend the bureaucratic log jams we ran into. Best of luck in the future.”

Ok. So, I am a little embarrassed by my trusting nature and the way I let the corporate dudes string me along.  And, I have always been critical of critics, even when I am the critic.  It is easy to criticize a process or organization, but unless you offer a viable alternative, it amounts to nothing but whining.  My way of dealing with this is to turn it in to something positive.

I reckon that, in preparation for this project it has cost me time, materials, and training fees, totaling nearly $7,300. Interesting that for just another 3o hours of my staff’s time, vehicle costs, and motel lodging, we can collect the samples in a scientifically relevant way.  Therefore, I am proud to announce that we are initiating the Yellowstone Biological Assessment Project, independently, as a community service. There will be laboratory time as well, but hey, that’s what winter nights are for, right…. (?)

If we do not ante up, and get this done right, there will be lots of paper pushed, but the world will be no closer to understanding the impacts of Exxon’s Oil spill on the Yellowstone River ecosystem. Our survey will not be able to cover everything, but it will provide more information than either the state, or Exxon will gather.

We will be sampling this week.   I’ll keep you posted. Full-speed ahead!

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Yellowstone oil spill and macroinvertebrate ecology

Tuesday, July 5th, 2011

The Yellowstone Floods and with it the oil moves to riparian areas

The Exxon-Mobil oil spill on the Yellowstone River made national and international news this weekend; indeed, my first awareness of it came from the BBC news website.

As a macroinvertebrate ecologist, I cannot help but reflect how the aquatic insects might be affected.  It might seem silly to worry about “bugs” when images of beautiful white pelicans in oil-soiled plumage comprise the most interesting internet images. Still, it only takes a little imagination to reckon that pelicans eat fish, and fish eat bugs… so… the long-term ecosystem effects will be reflected in aquatic insect communities before they are manifest elsewhere.

There are many ways in which oils cause mortality in aq

uatic insects. First, were not just concerned with the heavy fraction of crude, but also the lighter petrochemical fractions which are toxic to insects. Obviously, we’re worried about accumulations of heavy fractions decomposing and reducing oxygen concentrations; the Yellowstone River’s fish and invertebrates require much greater dissolved oxygen concentrations than bottom dwellers of the Gulf of Mexico. Furthermore, exposure to lighter fractions can foul aquatic insect gills and directly suffocate them as well.

Additionally, there are issues with consumption of contaminated particles. Insects eat a variety of food-sources, but many of them are rather specific. Many of the Yellowstone River’s invertebrates scrape algae from the surfaces of stones (e.g., Glossomoma sp.). Some filter small particles from water using parts of their bodies (Brachycentrus) or structures they build along the river’s bottom (Hydropsyche sp.).   Among these filterers there those that filter very fine particles (e.g., Simulium), fine (e.g., Brachycentrus) medium (e.g., Hydropsyche), and larger (Arctopsysche) particle sizes. Similarly there are some aquatic insects that gather small particles from pools and eddies (e.g., Baetis sp. Paraleptophlebia sp.). Both the filterers and gatherers focus on relatively fine (<1mm) organic detritus. However, some focus on coarser detritus (Pteronarcys sp.) These groups could possibly exhibit differential responses.  Of Course there are predatory insects as well, and my surveys around Billings in 2005 suggest that there are many large burrowing dragonfly (Gomphidae; Ophiogomphus) larvae (incorrectly called nymphs, naiads).

Predatory insects are particularly compelling because they will eat what is alive and capture able. They will consume many prey as they live, often for 2 or more years, and build up organic compounds in their tissues.  Thus they have the capacity to bio-concentrate lipophilic compounds (many petro che

micals are lipophilic) and move them up the food chain. Thus, it is important to document the how petrochemicals persist in the food chain to ensure that the spill does not result in fishes that are unfit for human consumption. This would be detrimental to our lifestyle and livelihood in Montana.   In the Yellowstone River, if this were to occur, large predatory insects are the most likely avenue of bio-concentration. Fortunately, there are so many insects (usually) in the Yellowstone River, it is easy to assess this; we can assure this does not become a problem…

From a Bug’s perspective, the timing of the oil spill is terrible: This is the time of year that many species leave the water to fly about, mate, disperse, and lay eggs in the water. I have seen regular old treated sewage foam interfere with insects leaving the water (called emergence) by adhering to their wings. The entire emergence process is driven by the surface tension of water…  Fortunately many tributaries and upstream areas are not exposed to the oil sheen, and the recolonization potential of aquatic insects is tremendous

(wings are very useful for such an endeavor). It is likely, if clean up is well executed, that many aquatic insect species will have normal populations in about 1-3 years.

This may sound strange to readers, but it is discovering exactly how these ecosystems rebound from tremendous

Burrowing dragonflies

stressors that I find is the most fascinating facet of my job.

Well the bugs themselves are pretty amazing in their own right… but ecosystem

recovery is pretty darn interesting.

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Biological Monitoring Covariates

Thursday, August 5th, 2010

When monitoring environmental impacts of anthropogenic activities, it is useful to collect ancillary data to use as covariates. These variables can help account for natural variation in the communities studies, which helps prevent their confounding of observations. In our work with benthic macroinvertebrate assemblages, we always collect flow measures for this purpose (near-substrate flow measures can account for much of the variation in simple benthic communities (e.g., Hart & Finelli 1999). With a sufficiently rigorous sampling design, the effects of flow on the community can be “teased” out of the analysis, so that the effects of anthropogenic stressors on benthic communities changes can be more accurately assessed–assuming, of course, that flow is not part of the anthropogenic impact in the study area.

Moss, macrophytes, and filamentous algae can also alter the abundance of certain types of macroinvertebrates. Moss, is not palatable to most macroinvertebrates because of the presence of protective chemicals. However, it does offer refuge from the sheer-forces of fast water. It also traps detritus (food), and can increase the amount of surface area available for colonization. Thus the presence of moss can have a strong influence on the structure of macroinvertebrate assembleges sampled in an assessment. When we want to account for this variation, we have found that the simplest (and effective) way, is to take a known amount of alcohol from the preserved samples and rank their Greenness. The Rank can be a very useful covariate when the data are analyzed. Other important covariates usually include a particle index, velocity, and depth.

The assumption is that the “Greenness” of the sample’s preservative is proportional to the amount of material soaking in alcohol for a given amount of time.  Thus, more greenness indicates there is more living plant material collected in the sample. Samples of similar greenness were probably influenced by living plants similarly, whereas the community composition of a very pale sample was probably influenced less by plant material than a sample with deep green preservative.

There are other nuances as well. For example, periphyton may cause a different kind of green tint to preservative than moss does–and it is likely to have a different influence on the benthic assemblage. Fortunately, for our purposes, moss seems to have much stronger effect on the sample’s color than periphyton. Also, you need to ensure that all samples are preserved with the same type and strength of preservative (95% ethanol, or 90% Isopropanol, or 90% denatured ethanol, not some of all three). Samples preserved in formalin would need to be transferred to alcohol before analysis–and even then should not be compared with samples preserved only with ethanol because of formalin’s ability to “fix” pigments.

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Odonata: Montana & Wyoming Aquatic Entomology Notes

Wednesday, August 4th, 2010

the mona lisaSo I started with one of my favorite little beetles, the Haliplids, but really, honestly… the aquatic insect with which the general public is most fascinated is probably the Odonata (dragonflies and damselflies). This seems to exclude fly-fisher-persons from the category of general public (because of their obsession with mayflies, caddisflies, and stoneflies). But, lets just consider fly-fishers exceptional members of the general public, that are out numbered by people with a certain nostalgia for the lazy summer days of their childhood. So powerful is the connection of Odonata with these memories, that many sylized dragonflies are emblazoned on many house items are commonly available (Wal Mart, k-Mart, Tiffany & Co.).   I believe most people associate these images with some un-nameable inner peace, but maybe that’s just me.  I do know one woman, who thinks dragonflies are nothing more than sexual predators, but she has issues (which may or may not be justified; who am I to judge?).

The images associated with this post are from the Wyoming Educational Benthic Imaging Project, funded by the Wyoming Assoication of Conservation Districts, who along with EcoAnalysts, retains a limited copy right to the images. As the artist I retain full copy rights. if you’d like to use them, please let me know. Just please be sure to give credit where credit is due.

This dragonfly family is the Gomphidae; known as club-tails or Snake-tails because of the adult’s expanded abdomen, somewhat resembling the “hood” of a cobra. Honestly, it was so long ago when I examined these specimens, I don’t remember their genus. Still, there are generalizations about the gomphids that can be drawn from discussing these specimens–some of which apply to most (or all) dragonflies and damselflies.  For those curious specifically about dragonflies in Montana and Wyoming, I cam tell you that the most commonly collected genus of Gomphidae in the region appears to be Ophiogomphus sp.; this could be largely because of where people are sampling (riffle areas in valley streams).gomphid head

The fact that these dragonflies covered with bits of fine detritus tells something about their way of life. The gomphid dragonflies are burrowers; they burrow into sand or silt and wait just below the surface for a prey animal to wriggle into striking range.  The complete and total coating of this nymph with sediments probably reflects the the nature its habitat. Specifically, the sediment were this critter was collected is probably much more organic than the habitats used by the upper specimens.  Seeing this specimen with hairs, antennae and even its eyes coated with a layer of “dirt” might suggest this critter was in a habitat that is somewhat inhospitable. However, this specimen was very large–nearly complete larval development–suggesting that this degree of sediment did not affect the    Other species very likely could not survive this amount of organic sediment. For example, the function of mayfly gills would very likely be impeded by a similar coating; resulting in suffocation.

Educators: here is a thought question to ask your students: Why do you think the dragonfly did not suffocate, where many mayflies would?

This specimen gave me a nice chance to photgraph something that is usually a little hard to photograph: the feeding structures of larval dragonflies. [NOTE: larval dragonflies are sometimes incorrectly called "nymphs," but this term refers to animals with "incomplete metamorphosis" (e.g., true bugs, grasshoppers, cockroaches) not those that are paurometabolus (mayflies, stoneflies, dragonflies, damselflies).] The principle adaptation of dragonfly larvae to the predatory life style is the modified labium (lower lip). This structure takes many forms in different insect species, but in dragonflies it is greatly elongated and hinged. The picture here shows the structure, viewed from under the head.  Often, the details of these structures do not photograph well, becasuse of a lack of contrast (yellow-white, on yellow-while, with low depth of field= poor photo). however, the sediment on this specimen allowed for a wide range of contrasts. Imagine this large plate-like structure folded at the lower-right corner of the photo, so that its total length is about 2 times what you see here.  Larval dragonflies, are slow movers; they are lie-in-wait predators. Unlike predatory stoneflies which chase down their prey dragonflies slowly stalk prey and wait for it to come into range.  Although, dragonflies are slow movers, they can rapidly compress their body, resulting in a brief increase in hydrostatic pressure, that cause the labium to launch forward with amazing speed–hardly visible.  The hooks (upper left of picture) puncture the prey and pull it back to mouth where it is held to be chewed and eaten at leisure.

This feeding style is ubiquitous among the Odonata (both dragonflies and damselflies).   Different species and families have different modifications of the labium and this one of the predominant structures used to differentiate larvae taxonomically and systematically.

Educators: here is a thought question to ask your students: How would growth of larval dragonflies change the kinds of food available to them?

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Wyoming Educational Benthic Macroinvertebrate Project

Thursday, July 1st, 2010

Aquatic insect Images from Montana and Wyoming; if you like this sort of thing let me know.



I just have time for a quick post today.

A few years ago, I prepared a collection of about 400 aquatic insect pictures to be used in by educators. Lisa Shaw, of Niobrara Conservation District, was essential in attaining funding from the Wyoming Association of Conservation Districts. The project had huge ideals: We were going have all the conservation districts send in aquatic insect specimens from all over the state of Wyoming. The idea was to have educational field trips and send in as may different bugs as possible. Some districts did just that. Some sent one person out on a solo mission, and others sent in jars or unsorted detritus (which all contained bugs).

The project was more work than expected, and my employer (at the time) withdrew support of the project, pressuring me to work on it on weekends and evenings.  Regardless, we managed to develop an impressive set of images  of the finer characteristics of aquatic insects that much of the general public never would never see otherwise. It included  whole-bug context pictures and close-ups of interesting parts… eyes, mouth-parts, gills, etc…

I would hate to have this resource fade way. I’ll post some pictures from it here from time to time.  If you are interested in attaining a copy of the document, post a comment here so I can gauge community interest in these wonderful aquatic insect pictures.

I found this Dytiscus predaceous diving beetle during my wedding–with the eager help of my nephew and brother in-law… um… from my wife… um… not so much.

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~Jefferson River Montana~

Friday, June 25th, 2010

The Jefferson River Flooded last weekend. All the hay fields in the area were flooded and roads that have not been submerged in recent history became gentle rivulets. The High water is good for the Jefferson River because it has had many years of below average flows–and fine sediments have built up among the interstitial spaces were many invertebrates that are important fish forage live.

When Snorkeling in recent years, I have found that if you pick up a cobble, there is beneath it only sand. Typically, you might expect to find more cobbles under cobbles. Among the sand grains are the burrows of several sediment dwelling invertebrates (e.g., Hexagenia and Ephoron sp.). According to locals, the river once supported impressive hatches of large stoneflies (Hesperoperla pacifica, Pteronarcys sp. etc).

When sediment fills in the the area under the stones, much of the habitat used buy large stone flies is lost because the interstitial spaces are simply too small for them to pass through. This results in smaller populations (of large invertebrates), and ultimately smaller hatches. It may also reduce the forage available for fish. For example, it appears that sedimentation of the Jefferson River may have caused Burrowing dragonflies (Gomphidae) to replace many of the large predatory stoneflies typically expected. We sampled the Jefferson River several years ago and found about 2-3 gomphid dragonflies per square foot and about 0.3 large stoneflies in the same area–the dragonflies were nearly 10x times as abundant as the stoneflies.  We are hopeful  that high river levels will scour sand from interstitial spaces and improve survival of stoneflies. This could result in an improvement in fishing a few years down the road…

Aside from benefiting river ecology, another effect of the flood is that pools and back waters that have not been flooded for years have now been nicely inundated for a week or more. Mosquito eggs can remain dormant for several years–until they become wet.  We found hundreds of thousands of mature mosquito larvae and pupae among the grassy ditches and fields last weekend. There were so many larvae, that in just a few minutes we observed hundreds of larvae washing across the road in shallow riffles (picture below).  By this weekend or early next week the Jefferson Valley will likely be swarmed by endless squadrons mosquitoes… and it has been such a nice spring.  If you can tolerate the bites and buzzing it might be a nice weekend to try mosquito-mimic flies… and if you have a friend who owns a hay field… maybe see if you can get permission to fish it!

mosquitoes float across the road

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~Holston River Tennessee~

Thursday, June 24th, 2010

The Zone of periodically inundated waters is called the “varial zone” and the community structure can deviate dramatically from the structure of permanently inundated river bottom.

RiverContinuum.org

We are gearing up for our joint venture with the Academy of Natural Sciences to sample the Holston River near Kingsport Tennessee. I last surveyed this river when I managed the Invertebrate Zoology Research section of the Academy’s Patrick Center for Environmental Research in 1997.  The Academy will be collecting water chemistry, algae, fish, qualitative non-insect macroinvertebrates, and quantitative insects (that’s me!) From July 10-July 20 2010.

The project is difficult because the flow of the river fluctuates with hydro-power generation. High water can present safety challenges, but it can also produce sampling challenges. For example, we don’t want to sample part of the river that was bone-dry two hours earlier… it would definitely cause confounding results when the data are compared to locations that were sampled in perennial flowing zones.  The Zone of periodically inundated waters is called the “varial zone” and the community structure can deviate dramatically from the structure of permanently inundated river bottom.  Fortunately, on the Holston we can tell if the rocks were recently exposed to the air for long time periods because stones become crusted with algae or sediment.

Spending a little time identifying the varial zone boudary can really save you from heartache latter, when you try to explain why the study’s results are confounded by sampling issues.  To help avoid these problems, we will spend a day visiting the sites to grab flow measures and identify the amount of lateral/vertical changes in river height (depth).  Also, local news papers usually publish river gauge stage readings and the USGS web page can often provide real-time river height information.  One thing to remember is that these readings are usually reported from dams or bridges, and it may take several hours from from the time a flow spike is recorded and the time it reaches your sample location. If you spend sometime before sampling you can get a feel for time of lowest water at each location.

The Sampling device we will use is the Portable Invertebrate Box Sampler (PIBS)– for those in the know, it is like a rectangular, enclosed Surber Sampler with a foam-sealing base.  It can be used in water depths from 10cm to ~35-40 cm without modification. Therefore, in rivers like the Holston, it is important to try to sample at the period of lowest water so you are sure to collect from the perennial zone… Remember, if the water-level is 50 cm higher than base flow, it will be too deep to reach the perennial zone with the sampler… The Surber would require even a shallower (<30cm) high flow to be effective. Hess samplers are highly variable in their construction and can be modified to work in deeper water, but remember the limiting factor is the length of your arms… if you can’t reach the bottom of the sampler to scrub the cobbles, you cant collect the sample.

I am personally excited by this trip because the downstream site, is one of the most diverse benthic assemblages… it is absolutely lovely!

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~New Fork River~

Thursday, June 24th, 2010
The Mona Lisa

Photo: B. Marshall

We have been working most of the winter on samples from the New Fork River and the Upper Green River in Sublette County Wyoming. It is fun to get back into the grove of identifying samples.   We just hired a new Technician Esmeralda (who’s bio is not yet posted on the web page) to help make the report deadline. Esmeralda is incredibly efficient and a welcome relief to laboratory staff.  Sorting is now proceeding at a much faster pace.

One of the interesting specimens we’ve found is a tusked Paraleptophlebia nymph.  There are two western species of Paraleptophlebia that have tusks that are believed to assist with burrowing (P. bicornuta and P. Packi). The outer margin of the mandible is expanded to form the tusks and the head is more directed forward (prognathous) than in other species of Paraleptophlebia making the nymphs appear different and more predatory.

Edmunds and McCafterty (1996) compared the behaviors of burrowing mayflies and reported, “Paraleptophlebia packi forms burrows in silt, whereas P. bicornuta is an interstitial dweller.”  It would be interesting to differentiate these species because the impacts we have been discussing in the report are related localized sedimentation related to gas well development and other land use activities. Changes in the relative abundance of these species might result from changes in the amount of sediment entrained in the river. Unfortunately it is very difficult to separate nymphs of these species with “nice” specimens and ours are not in ideal condition. Furthermore, it is not clear when the tusks become apparent; many of our younger Paraleptophlebia nymphs may be P. packi or P. bicornuta that have not yet developed the prominent tusks which differentiate them from other species. Thus, even if we were to differentiate the species with mature speciemens, ontogenic  morphological changes within the species might cause spurious results when most of the nymphs are immature.

Thought Question: How else might ontogeny affect biological assessments of streams and rivers?

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