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, https://leafpacknetwork.org/biotic-index/, 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.

Posted on December 4, 2017 03:51 PM by mattgeo1990