Archivos de diario de diciembre 2017

04 de diciembre de 2017

Preliminary Ecological Survey of Upper Cibolo Creek in Boerne, TX (Locality A, 12-2-17)

I have begun a leisurely study of the ecological and biological status of Cibolo Creek in Boerne, TX. On the morning of Saturday, Dec. 2, I took a limited survey of flora and fauna at a locality on Cibolo Creek, roughly 50 yards upstream of the bridge at John's Road. This included some trees, grasses, aquatic plants, fishes, terrestrial insects, and aquatic benthic macroinvertebrates. Flow rate and water level were very low compared to previous observations (April 2017) of this section of Cibolo Creek. Flow rate is estimated at less than 0.5 ft3/s. Some notable observations:

-Low flow rate, pools are somewhat stagnated. Benthic algal growth is significant.

-As noted previously (April, 2017), Justicia americana is predominant emergent aquatic flora at this locality.

  • Predominant submerged aquatic flora appears to be Ceratophyllum sp. , which is densely populated and abundant at this locality.

-Only observed fish taxon was Gambusia affinis, although several sunfish species have been observed here in the past, and are obviously present throughout most of Cibolo Creek in Boerne.

-Benthic macroinvertebrate sampling was limited to picking of specimens from underside of a few dozen submerged rocks within the fastest-moving water in a riffle. See associated observations for complete list of fauna. Notable observations include leeches (Hirudinea), flatworms (Dugenia), midge larvae (Chionomidae), and mayfly larvae (Ephemeroptera). Using the Leaf Pack Network® Biotic and Water Quality Calculator,, a biotic index of 6.46 was calculated, indicating fair-poor water quality with "substantial pollution likely". Note that macroinvertebrates were abundant, and that Argia sp. was the predominant taxon. Also note that more robust and thorough sampling is necessary.

Publicado el diciembre 4, 2017 03:51 TARDE por mattgeo1990 mattgeo1990 | 37 observaciones | 0 comentarios | Deja un comentario

14 de diciembre de 2017

Native Distribution of Bauhinia lunarioides (Anacacho Orchid)

I have noticed that there are a number of observations of B. lunarioides along the I-35 corridor, as well as one in Nueces County. USDA and University of Texas (Ladybird Johnson Wildflower Center Native Plant Database) report a native range limited to the Del Rio region of Texas and the adjacent region in northeast Mexico. The USDA does not report any counties where B. lunarioides has been introduced and occurs naturally. Considering the aesthetic value of this species, it seems possible that most, if not all, of these observed specimens on iNat are actually cultivated, and should be marked as so.

Publicado el diciembre 14, 2017 02:56 TARDE por mattgeo1990 mattgeo1990 | 0 comentarios | Deja un comentario

18 de diciembre de 2017

Preliminary Ecological Survey of Shady Branch, Giles County, TN (Richland Creek Tributary)

On December 17, 2017, I took a limited collection of aquatic macroinvertebrates from "Shady Branch", an apparently unnamed tributary to Richland Creek in northern Giles County, TN (Stream enters Richland Creek at Lat/Long: 35.286059, -87.026932). Samples were taken from undersides of about 12 submerged rocks. Flow rate is estimated at between 2 and 5 cfs. Turbidity was very low, water was completely transparent. Stream originates at spring less than 0.25 miles upstream on same property, but is also fed by two small tributaries from the north, which both transect cattle pastures. Property at locality is historically a cattle farm, but has been utilized as row-crop farmland for 5 years. Sampling locality (Lat/Long: 32.285678, -87.016789) was just upstream of first tributary entering Shady Branch.

Observed macroinvertebrates include: Ephemeroptera (2 very small specimens [~5 mm]), Hydropsychidae (6 specimens collected, but more were observed in the stream. Taxon was abundant), Gastropoda (5 specimens), Amphipoda (1 specimen), and Dugesiidae (1 specimen). Biotic Index Calculator produced biotic index of 5.56, or "Fair" water quality with "substantial pollution likely".

More thorough sampling will be necessary. Water samples should be collected from spring source (A), first tributary (B), second tributary (C), and just upstream of mouth at Richland Creek (D), and tested for nitrogen levels, fecal bacteria, and other livestock-related contaminants.

Publicado el diciembre 18, 2017 03:01 TARDE por mattgeo1990 mattgeo1990 | 7 observaciones | 0 comentarios | Deja un comentario

21 de diciembre de 2017

Notes on Ephemeroptera

"The Heptageniidae family contains the angler's "clinger" type mayfly nymphs commonly referred to as "Flat Heads" by entomologists. They sport flattened profiles, blunted broad heads, and stout legs suitable for life in fast water. Their flattened tear drop shape is a "miracle" of nature's hydrodynamic engineering employing the same principles used by Formula One race cars to hug the road and reduce wind resistance."

Genera in family Heptageniidae (iNaturalist):
Genus Afronurus
Genus Anepeorus
Genus Cinygma
Genus Cinygmula
Genus Ecdyonurus
Genus Electrogena
Genus Epeorus
Genus Heptagenia
Genus Iron
Genus Ironodes
Genus Leucrocuta
Genus Maccaffertium
Genus Macdunnoa
Genus Nixe
Genus Raptoheptagenia
Genus Rhithrogena
Genus Rhitrogena
Genus Spinadis
Genus Stenacron
Genus Stenonema

Publicado el diciembre 21, 2017 05:42 TARDE por mattgeo1990 mattgeo1990 | 4 comentarios | Deja un comentario

Notes on Caddisflies (Trichoptera)

"Most caddisfly larvae live in cases they build out of sand, rock, twigs, leaf pieces, and any other kind of underwater debris. Some even generate their own cases out of silk. There is tremendous variation in case style and also in the way the larvae manage their cases: whether they replace it as they grow or renovate their old one, and whether they carry it around or fix it to an object. Trout love to eat these larvae, case and all.
Other common caddis larvae build nets instead of cases. These are not residences but hunting traps, like tiny spider webs, designed to capture plankton and smaller aquatic insects the larvae eat. One larva may build more than one net and roam freely around the rocks and logs tending to each and ingesting the catch. The net-spinning families, in order of abundance, are Hydropsychidae, Philopotamidae, and Arctopsychidae.

In many species, the pupae become very active just before emergence and drift along the bottom of the river, sometimes for hours. The "deep sparkle pupa" patterns introduced by Gary LaFontaine in Caddisflies are the most popular of many imitations inspired by this behavior. It is a deep nymph fisherman's dream. Sometimes they drift similarly just below the surface for a long time before trying to break through.

Pupae of different species use three different methods to emerge:

Most species rise to the surface and struggle through. They usually take flight quickly once they're out of the water, but slow species first struggle and drift long distances half-submerged as they wriggle free from their pupal shucks.

-The pupae of some species crawl out of the water on rocks, sticks, and such, so that the adults emerge high and dry.
-Some pupae rise to the surface and swim quickly across it to shore where they crawl out to emerge.
-Most caddis pupae are good swimmers, and they use their legs as paddles rather than wiggling their bodies to move.

After emerging, caddisfly adults live for a long time compared to mayflies, in part because they are able to drink to avoid dehydration (mayfly adults cannot eat or drink). This flight period lasts anywhere from a few days to a few months, depending on the species, so mating adults may be seen on or over the water long after emergence is complete."

Publicado el diciembre 21, 2017 06:14 TARDE por mattgeo1990 mattgeo1990 | 3 observaciones | 0 comentarios | Deja un comentario

22 de diciembre de 2017

Notes on Snail Darter (Percina tanasi)

Being a Tennessee native, I was interested when my recent study of darters led me to become familiar with the controversy of the snail darter and the TVA's construction of Tellico Dam in the late 1970's. For information about the snail darter controversy, google "TVA vs Hill (1978)". The lead counsel representing the farmers, Cherokee, anglers, and environmentalists who opposed the dam, Zygmunt Plater, wrote a book about the case and its implications titled "The Snail Darter and the Dam: How Pork-Barrel Politics Endangered a Little Fish and Killed a River".

"The snail darter is a federally protected species and is listed as threatened under the Endangered Species Act of 1973 as a result of habitat destruction from the completion of the Tellico Dam."

On the status of the species, from the USGS (
"The Snail Darter was intentionally introduced to create an additional population of this endangered fish when its only known habitat was threatened by construction of a dam. Seven hundred and ten Snail Darters were introduced into the Hiwassee River from June 1975 to February 1976 (U.S. Fish and Wildlife Service 1982a; Etnier and Starnes 1993). In October 1975, 61 were introduced into the Nolichucky River. Introductions into the Nolichucky River were halted when the sharphead darter Etheostoma acuticeps was discovered there, for fear the introduction would jeopardize this rare species (U.S. Fish and Wildlife Service 1982a; Etnier and Starnes 1993). The Holston River was stocked with 533 Snail Darters from the Hiwassee and Little Tennessee rivers during the period 1978 to 1979. The Elk River was stocked in July 1980 with 425 Snail Darters from the Little Tennessee River (U.S. Fish and Wildlife Service 1982a).
Status: Established in Hiwassee River and range expanding (U.S. Fish and Wildlife Service 1982a). One darter observed in Nolichucky River in 1980. Single individual possibly from small reproducing population or escapee from fish hatchery upstream; none found since. Elk River populations apparantly extirpated due to failed introduction (Etnier and Starnes 1993). Snail Darters found in lower French Broad and lower Holston rivers in 1988 and 1989 presumably represent progeny of Holston River transplants (Etnier and Starnes 1993). In 2005, Ashton and Layzer (2008) found robust populations in French Broad and Hiwassee Rivers, and low abundances in Holston, Little, and Sequatchie Rivers and Big Sewee and South Chichamauga Creeks. Ashton and Layzer (2008) suggested that these low population sizes may be due to a lack of reproducing populations in these streams, with individuals migrating into these streams from larger, reproducing populations in French Broad and Hiwassee Rivers."

Publicado el diciembre 22, 2017 09:26 TARDE por mattgeo1990 mattgeo1990 | 0 comentarios | Deja un comentario

26 de diciembre de 2017

28 de diciembre de 2017

Notes on Freshwater Cnidarians, Bryozoans, and Poriferans of North America

While previewing Thorp and Rogers' (2010), "Field Guide to Freshwater Invertebrates of North America", I learned that the phyla Bryozoa, Porifera, and Cnidaria have freshwater representatives, and in North America, no less. I was interested to learn this of sponges and bryozoans, but excited to learn it of cnidarians. It seems that three families are represented in freshwater habitats of North America: Hydridae (hydras), Clavidae (clavid hydrozoans), and Olindiidae (hydrozoan jellyfish).

Publicado el diciembre 28, 2017 08:50 TARDE por mattgeo1990 mattgeo1990 | 0 comentarios | Deja un comentario