Hybrid Darters

This area of Ohio lies in place of the old teays river valley. When glaciers pushed southward, they deposited lots of till in the valley which now helps to act as an aquifer. it holds ground water very close to the surface. I believe this is what keeps these ditches alive. I am sure Todd can expound on this.

This area of Ohio lies in place of the old teays river valley. When glaciers pushed southward, they deposited lots of till in the valley which now helps to act as an aquifer. it holds ground water very close to the surface. I believe this is what keeps these ditches alive. I am sure Todd can expound on this.

Oh no, it works in the Great Black Swamp soils too. I mean, this is exactly what is going on where you were when you got these darters, but it operates the same in all low-gradient streams and ditches. This is what prairie stream assemblages and environs look like. I think Neely has some pictures from one in Iowa that was relatively undisturbed (Dave?)

I've attached a final report that was my thesis, if people would like to read it. In a depauperate system in the Lake Erie watershed, we pulled 24 species of fish from our (12) 20 meter plots in 11 sample events. Below is the executive summary, if you'd like to read it before downloading. I'm in the process of getting this into form for a journal, and hope to have it submit by the end of the semester.

It makes me mad as hell that we're still treating these streams as nothing more than culverts. If I can pull a relict assemblage like this out of a s___hole like the upper Ottawa River, think of the potential for treating these like streams for once!

The Outlet near Findlay that we all keep talking about is a slightly better situation. Definately has more of the assemblage still present (like creek chubsucker). I would expect a much higher IBI from the Outlet because of eveness in species, lower counts of Pimephales, and the much greater presence of suckers. It feels like about a 45. Might be worth it next May to run one with seines and see how the DNR does vs us

Todd "Sendin' love out to all my Ditches and Backhoes" Crail

 LEPF_Final_Report_6_22.pdf   918.85KB   9 downloads

Executive Summary

Colonization by wetland plants of channelized stream banks and the resulting fluvial
geomorphology are surmised to produce more-stable channel cross-sections and improve
water quality. We tested the impact of such colonization on the structure and composition of
fish communities in farm ditches of the Ottawa River, a western Lake Erie tributary, by
comparing twelve 20-m stream segments with and without plant intrusion (heterogeneous or
Ht and homogeneous or Ho, respectively).

Fish communities were sampled by sweep and block seine in each segment eleven
times between June 2005 and October 2006. Measurements of pH, temperature, turbidity,
DO2, conductivity, canopy cover and discharge were comparable between Ht and Ho
segments at each sampling event.

A total of 10,501 fish representing 24 species were identified and released. Only
0.6% of the total catch belonged to non-native species. The average Shannon diversity,
species richness and number of trophic guilds were significantly higher in Ht segments
(p=0.028, p=0.029, p=0.008, respectively). Moreover, Ht segments appeared to host greater
abundance (119.7 ± 32.2) than Ho sites (53.5 ± 13.8 ) although that difference was only
significant at the p=0.074 level due to large inter-annual variability in fish abundance within
each habitat type. The Index of Biological Integrity was not significant different between
habitats (HT= 21.8 ± 0.1; HO=21.2 ± 0.2).

Our census included 1,615 least darters, Etheostoma microperca, a previously
undocumented population and listed as a State Species of Concern in Ohio. Seines were an
effective, non-lethal tool in our fish sampling protocol. These farm ditches showed a
surprisingly robust, species-rich fish community that may be maintained by allowing wetland
plant colonization along stream banks.

In spite of decades of continual disturbance by humans and a misinformed reputation
for being little more than a culvert to drain excess water away from agriculture, the
channelized and entrenched headwaters of the Ottawa River possess a developed fish
community composition and structure that ranks “Fair” in comparison to statewide IBI
assessments of streams. Although dominated by two tolerant species, the habitat is suitable
for a large population of the State Species of Concern least darter, in addition to twenty other
native species of fish. While present, three exotic species were an insignificant proportion of
the fish community composition and structure.

Furthermore, within these streams, segments possessing a heterogeneous
geomorphology host a significantly more rich, diverse and trophically-varied fish community
than segments with less developed, homogeneous geomorphology. In the case of our study
sites, colonization of plants contributes to the formation of the heterogeneous morphologies.

Ok, now that I did go ahead and derail the hybrid thread, I've got another question - or two.
Why is there not phragmites and loosestrife choking out those ditches? Are those not an issue in that area? Are they removed?
Having never been to the region, it's hard for me to reconcile the condition of the ecosystem you describe as compared to the condition of what seems [on the surface at least] to be very similar habitat found here.
I'm thinking maybe the volume of ground water keeps the ditches from getting as stagnant as they do here. Chanalized ditchs in such low gradient terrain here wouldn't flow much except during times of runoff. They'd stand there slack, breeding mosquitos, and turn into long thin strips of marsh consisting of rushes and loosestrife. I can't even think of a single fish species that would survive any significant distance from a more natural stream.

There was actually more than that in there. We got Rainbow and orangethroat darters as previously stated but we also got least darters, creek chubsuckers, creek chub, bluntnose minnows, central stoneroller, striped shiners, tadpole madtom, blackstripe topminnow, hmm Matt and Thom am I forgetting any?
Rockbass

Brian,
Didn't we get a fantail there too?
-Thom

Why is there not phragmites and loosestrife choking out those ditches? Are those not an issue in that area? Are they removed?

The soils aren't rich enough for phrag and the purple plague. The pictures you're seeing are low gradient, but up a bit of elevation so that they're washed ground moraine. In any competitive situation, these species prefer rich deltaic or productive soils caused by low flushing rates that build up nutrients as a result of high primary productivity (they're nitriphiles). Along roadsides, they prosper due to seasonal disturbances from mowing paired with road salting. I hypothesize that they benefit hugely due the absence of seed bank of the native plants that would be competitors. I would also hypothesize that their rapid invasion was facilitated due to this missing seed bank after sediment and fertilizer pulses choked out deltaic wetland areas. I really wish people would begin to run experimental treatments in this mindset, instead of assuming that invasive species themselves are the "ultimate competitors". I've not seen evidence of their competitive supremeness, other than the auto-correlation that humans are so prone to.

I'm thinking maybe the volume of ground water keeps the ditches from getting as stagnant as they do here. Chanalized ditchs in such low gradient terrain here wouldn't flow much except during times of runoff. They'd stand there slack, breeding mosquitos, and turn into long thin strips of marsh consisting of rushes and loosestrife. I can't even think of a single fish species that would survive any significant distance from a more natural stream.

Look at my ditch pictures in the pdf. Tiles drain the ground water to base very quickly. What remains that keeps these systems somewhat perenial is whatever geomorphology that formed during the higher energy pulses paired with a lacustrine clay that is so fine and compacted that it holds water as well as plastic. Recharge is only something that happens when it rains.

You also have to consider that the realm of your experience with these ditches is in the glaciated East, where the fish fauna is depauperate to begin with. In the midwest, we were lucky enough to have a fish assemblage to take over these systems once they stopped being wetlands. In your situation, those psuedo-perenial streams really aren't good patch habitats for the mummichogs, banded topminnows, and bluespot sunfish. I would not, however, be surprised for you to find tesselated darter and stickleback.

Todd

Yep your right Thom and it looks like Matt added Rockbass as well, so I did forget two species.

Looks just like my rainbows, except more colorful.

I would be interested in running the genetics on your specimens. There was a paper by Martin and Richmond (1973) in the Journal of Fish Biology on hybrids of these species in Ohio. I'm away from my office this week, so I don't have it in front of me or I would look up the locality that they sampled. They ran allozymes and failed to find genetic evidence of hybridization, and I have not found any Ohio River drainage mitochondrial hybrids in my work so far, but I would be willing to run a few more.

It would be interesting to find more random hybrids (so far, I have single individuals from the White, Black, and St. Francis River drainages and one from southwestern Illinois), since most of the individuals I have found with the "wrong" mitochondrial genome have been geographically clumped in populations that must be mostly, if not almost completely, introgressed (Etheostoma uniporum by E. caeruleum, E. fragi by an as yet unidentified culprit, E. spectabile in the Clear Boggy River of Oklahoma by E. radiosum, and E. spectabile in Bayous Meto and des Arc in Arkansas by two divergent clades of E. whipplei). All but one of the specimens with the "wrong" mitochondrial genome have had a "correct" allele at a nuclear marker (S7) and one specimen from a small Red River tributary in SE Oklahoma was the other way around.

The hybridization mess within the Etheostoma spectabile group is nothing compared to the nightmare that is the E. asprigene group (E. asprigene, E. caeruleum, E. collettei, E. ditrema, E. nuchale, and E. swaini). At least I can tell the E. asprigene and E. spectabile species groups apart using S7. Within a species group it has been much harder to figure out what might be going on.

Nick Lang
(I haven't posted much, so I figured no one would recognize my screen name)

I wouldn't consider you one of the usual skeptics...

Anyways 2 of the specimens have been catalogged into the Museum collection as OSUM 105231, along with an entire fin off of each in 95% etoh so if anyone wants to look into the genetics it is possible for 2 of these.

Todd I'm sending you the location so if you want to go back and get more some time, let me know.