2016-04-29 Milkweed Road Survey; Loop to San Angelo and back to Goldthwaite

Chalk Mountain, US67., Stephenville, US67., Dublin. TX6, DeLeon, FM587, Rising Star, FM587, Cross Plains, FM206, Burkett, FM206, Coleman., FM206, US67, Valera, US67, Talpa, US67, Ballinger, US67, Miles, US67, San Angelo, Loop306 south, US87 east, Wall, CR2334 north, FM 765 east, Eola, FM 765, Millersview, FM 765, Doole, FM 765, Fife, FM 765, TX45 north, FM 574 east, Goldthwaite .

http://www.inaturalist.org/observations?nelat=32.44210530038949&nelng=-97.34298706054688&on=2016-04-29&place_id=any&project_id=texas-milkweeds-and-monarchs&swlat=31.158290560060113&swlng=-100.99594116210938&user_id=gregglee&verifiable=any

Stopped about every ten miles, unless previously surveyed or, no Milkweed (genus Asclepias) visible while driving. We did not stop to do foot search if none visible while driving.

We found Milkweed , mostly A. asperula, on most of the route. One A. viridis. Mostly similar to 2016-04-22 loop.

However unlike April 22, we went further west and crossed the western boundary for abundant A. asperula.. By boundary, I mean that while we did find some here and there, west of the boundary, A. asperula became less frequent the further we went west and large patches did occur at all.

West of US 83 there was nearly nothing. This area has nearly continuous flat terrain, tilled fields, with some crops emerging, most set up for irrigation. On the north side of our loop heading west, Asclepias numbers started fading about Coleman. Returning on the south side, heading east, some large patches appeared at about US377, but not all full strength until TX45. .

Correlation does not equal causation. I'm not suggesting that row crop agriculture is what limits A. asperula. More likely the terrain and soil that favors row crops does not favor milkweed. In fact the most wildflowers, cactus, grasses and other forbs growing with milkweed continued west even as asperula numbers declined. Some increased, two(?) types of yellow Paintbrush in particular. (Have not looked them up yet.) Bastard cabbage at roadsides did increase significantly right next to row-cropped fields.

The Invasive Eurobee, Apis mellifera occurred continuously on milkweed and other flowers
throughout trip, often outnumbering native pollinators, and frequently pushing them off flowers.

Posted on Μάιος 03, 2016 0213 ΜΜ by gregglee