Päiväkirja-arkisto kohteelle toukokuu 2019

27. toukokuuta 2019

The Tidal Wave that is Crete Weed

Crete Weed or Cretanweed (Hedypnois rhagadioloides, formerly H. cretica; Asteraceae, Chicorieae) is a native of the Mediterranean region, widely adventive in the southwestern United States particularly centered on urban areas and disturbed roadsides.
https://www.inaturalist.org/taxa/492864-Hedypnois-rhagadioloides
It is spreading in dramatic fashion in Texas so I wanted to get some framework on the distribution of this species. I have briefly consulted several manuals and floras available to me to look back at the origin of the species in Texas and the U.S. I did a search on Google Scholar for relevant articles on Crete Weed, along with searches of the Biodiversity Heritage Library and the JSTOR digital library. I downloaded specimen data for the Univ. of Texas herbaria (42 specimens) and from the TORCH (Texas Oklahoma Regional Consortium of Herbaria) database (76 records including the aforementioned U.T. specimens). Thus far, I have been unable to access the database for the S. M. Tracy Herbarium at Texas A&M University which will undoubtedly document more important records.

It’s initial establishment in Texas appears to have been quite early at Corpus Christi. The earliest specimen in the Univ. of Texas herbaria is from Nueces County, collected in March 1917 by E. J. Palmer (TEX 7678). In their “Manual of the Vascular Plants of Texas”, Correll & Johnston (1959) mention only that Crete Weed was “local on coquina beds at shoreline near Corpus Christi.” Fred Jones collected the species in the Corpus Christi area in the 1950s and 1960s. By the mid-1970s, Crete Weed was found “around Corpus Christi, w. of Portland, e. of Calallen, [and] Rockport” (Jones 1977). These localities are in Nueces and San Patricio counties. By 1987, the species had become established inland in Duval County.

The next regional establishment seems to have started in Austin County where Larry Brown collected the species in 1983-84*. I am not aware of the specific locality of the Brown specimens; the coordinates of specimens in the TORCH database refer to the geographic center of the county, but I suspect they may have been collected along the Interstate 10 corridor. It seems unexpected that the species would first be detected in a relatively rural county like Austin rather than in the adjacent urban center of Houston (Harris County). By 1990, Hatch et al. (1990) recited the species in their vegetational areas 2, 3, 4, and 6, which encompass coastal Texas, the Post Oak Savannah, Blackland Prairie, and South Texas Plains, but the county distribution within those regions is not delimited. Presumably the species had been documented from just a subset of the counties in the circumscribed area.

From the Austin County center, the species subsequently spread westward, being documented in Bastrop, Lee, and Travis counties in 1992, 1994, and 1996, respectively*. Bob O'Kennon found a first specimen for the Edwards Plateau in Gillespie County at Enchanted Rock in 1993. In the late 1990s, Diggs et al. (1999) recited only vegetational area 4 (Blackland Prairie) for North-central Texas (from Hatch et al. [1990]), indicating that the species “probably only [occurs] to the southeast of North-central Texas” (op. cit., p. 365). The species was first detected in the DFW metroplex in Fort Worth in 2001 and in Waco in 2004. From these various urban centers, the species has apparently continued to spread (or at least been detected) in adjacent counties.

Field work in the 1990s and 2000s established a number of new county records, documented by herbarium specimens*. Material in the several herbaria offer the following dates for earliest county records (TORCH database):

Chronological:
Nueces County (Corpus Christi), March 8, 1917 (TEX 7678; E.J Palmer)
Austin County (loc. uncertain), April 15, 1983 (BRIT 301633; Larry Brown)
Duval County (loc. uncertain), March 22, 1987 (BRIT 301732; Larry Brown)
Bastrop County (near McDade), April 18, 1992 (TEX 10539; Marshall Enquist)
Colorado County (near Columbus), April 16, 1993 (TEX 7677; Watson & Nesom)
Gillespie County (Enchanted Rock SNA), April 22, 1993 (BRIT; Bob O'Kennon 11390E)
Lee County (CR 696 nr Burleson Co. line), March 22, 1994 (BRIT 301735; Shanna Eddings)
Jasper County (TX 63 in Angelina Nat’l Forest), April 20, 1996 (TEX 39471; Guy Nesom)
Travis County (Austin), May 3, 1996 (TEX 32473; Carr & Turner)
San Patricio (Ingleside), March 17, 1998 (TEX 39472; Carr & Gallyoun)
Lavaca County (US 90A nr Ponton Cr.), March 26, 1998 (TEX 39469; Carner & Turner)
Tarrant County (loc. unk.), April 8, 2001 (BRIT 301739; John Karges)
Bexar County (San Antonio), March 19, 2002 (TEX 454232; Bill Carr)
McLennan County (Waco), April 13, 2004 (TEX 440140; W.C. Holmes)
Johnson County (loc. unk.), May 6, 2006 (BRIT 301734; Larry Brown)
Harris County (Barker Res.), April 10, 2007 (TEX 445276; D.J. Rosen et al.)
Bell County (Fort Hood), April 1, 2008 (TEX 431511; Laura Hansen; Hansen 2010)
Coryell County (Fort Hood), April 3, 2008 (TEX 431510; Laura Hansen; Hansen 2010)
Brooks County (Falfurias), April 20, 2009 (TEX 428575; Turner & Kos)
Burnet County (Marble Falls), March 30, 2011 (NY 1269355; D. E. Atha)
Williamson County (Brushy Creek Lake Park), Spring 2012 (iNaturalist; Ryan McDaniel)
Frio County (I-35 roadside park near Moore), May 29, 2013 (TEX 463517; Turner & Kos)
Atascosa County (I-37 nr Pleasanton), April 11, 2014 (TEX 468499; Bill Carr)
Midland County (Midland), April 4, 2018 (SEINet, iNaturalist; Nathan Taylor)

Alphabetic:
Atascosa County (I-37 nr Pleasanton), April 11, 2014 (TEX 468499; Bill Carr)
Austin County (loc. uncertain), April 15, 1983 (BRIT 301633; Larry Brown)
Bastrop County (near McDade), April 18, 1992 (TEX 10539; Marshall Enquist)
Bell County (Fort Hood), April 1, 2008 (TEX 431511; Laura Hansen; Hansen 2010)
Bexar County (San Antonio), March 19, 2002 (TEX 454232; Bill Carr)
Brooks County (Falfurias), April 20, 2009 (TEX 428575; Turner & Kos)
Burnet County (Marble Falls), March 30, 2011 (NY 1269355; D. E. Atha)
Colorado County (near Columbus), April 16, 1993 (TEX 7677; Watson & Nesom)
Coryell County (Fort Hood), April 3, 2008 (TEX 431510; Laura Hansen; Hansen 2010)
Duval County (loc. uncertain), March 22, 1987 (BRIT 301732; Larry Brown)
Frio County (I-35 roadside park near Moore), May 29, 2013 (TEX 463517; Turner & Kos)
Gillespie County (Enchanted Rock SNA), April 22, 1993 (BRIT; Bob O'Kennon 11390E)
Harris County (Barker Res.), April 10, 2007 (TEX 445276; D.J. Rosen et al.)
Jasper County (TX 63 in Angelina Nat’l Forest), April 20, 1996 (TEX 39471; Guy Nesom)
Johnson County (loc. unk.), May 6, 2006 (BRIT 301734; Larry Brown)
Lavaca County (US 90A nr Ponton Cr.), March 26, 1998 (TEX 39469; Carner & Turner)
Lee County (CR 696 nr Burleson Co. line), March 22, 1994 (BRIT 301735; Shanna Eddings)
McLennan County (Waco), April 13, 2004 (TEX 440140; W.C. Holmes)
Midland County (Midland), April 4, 2018 (SEINet, iNaturalist; Nathan Taylor)
Nueces County (Corpus Christi), March 8, 1917 (TEX 7678; E.J Palmer)
San Patricio (Ingleside), March 17, 1998 (TEX 39472; Carr & Gallyoun)
Tarrant County (loc. unk.), April 8, 2001 (BRIT 301739; John Karges)
Travis County (Austin), May 3, 1996 (TEX 32473; Carr & Turner)
Williamson County (Brushy Creek Lake Park), Spring 2012 (iNaturalist; Ryan McDaniel)

In the first published maps of the county distribution of the species, Turner et al. (2003) show the species occurring in 16 Texas counties with the bulk of the records in central Texas from Travis and Hays counties east to Waller County and south to Lavaca County. The complete list of counties in Turner et al. (2003) includes (bold = no records prior to 2003 in the above specimen list):
Austin, Bastrop, Burleson, Colorado, Duval, Fayette, Hays, Jasper, Lavaca, Lee, Nueces, Sabine, San Patricio, Tarrant, Travis, Waller.

The USDA PLANTS database (https://plants.sc.egov.usda.gov/core/profile?symbol=HECR2, accessed 23 May 2019) shows the same distribution as Turner et al. (2003) with the addition of McLennan County. The Biota of North America’s “Floristic Synthesis of North America” (BONAP, http://bonap.net/MapGallery/County/Hedypnois%20cretica.png, accessed 23 May 2019) adds seven additional counties (total 23 counties), the new records including Gonzales County in central Texas as well as Walker, Montgomery, and Galveston Counties in southeast Texas. The records for these two databases are primarily from herbaria records and reports from NRCS field staff. Counties mapped in BONAP include (bold = not listed among specimen counties above nor in Turner et al., 2003):
Austin, Bastrop, Burleson, Colorado, Duval, Fayette, Galveston, Gonzales, Harris, Hays, Jasper, Johnson, Lavaca, Lee, McLennan, Montgomery, Nueces, Sabine, San Patricio, Tarrant, Travis, Walker, Waller.

With increased observer activity and photographic documentation available on iNaturalist, there has been a substantial increase in the mapped distribution of Crete Weed since 2012*.
https://www.inaturalist.org/observations?verifiable=true&taxon_id=492864&place_id=18&preferred_place_id=1&locale=en
Below is a list of the earliest records on iNaturalist for 41 counties (as of May 24, 2019; grouped chronologically).
Bold font indicates counties not previously reported in any of the above sources:

2012:
Tarrant County (Chapel Creek), January 1, 2012 (@andyk)
Travis County (Austin), April 9, 2012 (Chuck Sexton)
Williamson County (Brushy Creek Lake Park), Spring 2012 (@rymcdaniel)

2016:
Dallas County (Cedar Hill SP), February 22, 2016 (Sam Kieschnick)
Harris County (Houston), February 29, 2016 (Andy Newman)
Milam County (near Rockdale), March 17, 2016 (Linda Jo Conn)
Kendall County (Boerne), April 2, 2016 (Gerry Salmon)
Hays County (San Marcos), April 3, 2016 (Amanda Carroll)
Aransas County (Rockport), April 23, 2016 (Andy Newman)
Lee County (TX 21 near Lincoln), May 24, 2016 (Linda Jo Conn)

2017:
Fayette County (US 77 S of La Grange), February 21, 2017 (Eric Keith)
Parker County (Azle), April 16, 2017 (@andyk)
Burnet County (FM 1431 near Granite Shoals), April 16, 2017 (Chuck Sexton)
Fort Bend County (Brazos Bend SP), April 16, 2017 (@beversol)
Waller County (Brookshire), April 18, 2017 (Julie Pearce)

2018:
Nueces County (Corpus Christi), March 9, 2018 (Pop Charlie)
Galveston County (Galveston), March 10, 2018 (Kimberlie Sasan)
Bee County (Beeville), March 10, 2018 (Pop Charlie)
Midland County (Midland), March 28, 2018 (Nathan Taylor)
Denton County (Southlake), April 1, 2018 (Jan Lapine)
Kimble County (South Llano SP), April 4, 2018 (Chuck Sexton)
Llano County (Kingsland), April 13, 2018 (@sideoats)
Wilson County (near Elmendorf), April 12, 2018 (@dianahuntermeow)
Cooke County (Gainesville), April 20, 2018 (@awright1818)
Johnson County (Burleson), April 27, 2018 (Sam Kieschnick)
Ellis County (Midlothian), April 27, 2018 (Deborah Rayfield)
Kleberg County (Kingsville), May 10, 2018 (Sam Kieschnick)
Medina County (loc. obscured), May 24, 2018 (@ygg_huur)
Guadalupe County (S of Seguin), November 3, 2018 (@csbarnes)

2019:
Lavaca County (Moulton), February 10, 2019 (@cjack)
Comal County (Canyon Lake), February 11, 2019 (@zorkkanna)
Live Oak County (I-37 near Three Rivers), March 14, 2019 (Michael Price)
Goliad County (Coleto Park Rd), March 15, 2019 (@hiker912)
Blanco County (Johnson City), March 20, 2019 (@billarbon)
Karnes County (Kenedy), March 21, 2019 (@eromero)
Lampasas County (Kempner), March 27, 2019 (Sven Bowsher)

Gonzales County (Palmetto SP), March 28, 2019 (Chuck Sexton)
San Patricio County (L. Corpus Christi SP), March 28, 2019 (Chuck Sexton)
Burleson County (TX 21 near Old Dime Box), March 28, 2019 (Isaac Lord)
Brazos County (College Station), April 18, 2019 (Megan Kossa)
Jefferson County (near McFaddin Marsh NWR), April 27, 2019 (Carol Price)
Collin County (Jack Carter Park), April 28, 2019 (@fhhpschmitt)
Caldwell County (US 183 near Luling), May 8, 2019 (@athena0443)

With the addition of all the Research Grade iNaturalist observations list above, a total of 59 counties now have records (specimens or confirmed observations) of Crete Weed. Updates and additions to the above county lists will be posted as comments to this article (see below).


Other States:

The species seems to have first shown up in California in the late 19th Century. Munz & Keck (1959) describe the species as a “local but rather widely naturalized weed” but give no more specific details of its distribution at that time. Crete Weed was first documented in Arizona in 1968 in Tucson (Mason et al. 1986). By 1986 the species was “well established and … locally abundant in the area of the University of Arizona” (Mason et al. 1986). A first report for Florida appeared on iNaturalist Apirl 29, 2019 (Old Bainbridge Co. Park, Tallahasee, Lake Jackson Co.; @katyjohelm). A report from Louisiana in April 2019 on iNaturalist was misidentified but the species is almost surely present along a major transportation corridor like Interstate 10.

Origin and Manner of Spread:

The origin of Crete Weed in the United States may have had multiple sources. The array of localities in the species early establishment in California are “widely scattered” in the Central Valley, the Sierra Nevada foothills, the Coast Ranges, and urban areas of Southern California. Regarding its appearance in Sonoma County around 1900, Robbins (1940, p. 98) quotes a report by Eastwood (1900) that Crete Weed was established where “at one time a large garden [was] worked by the Italians. It was doubtless through them that the weed was introduced.” It is not inconceivable that European immigrants from the Mediterranean area brought the species with them—probably inadvertently—with agricultural crops. Hanson & Mason (1985) indicated that Crete Weed shows up occasionally in bird seed in Britain, but since bird seed in North America is locally sourced, this may not be a regular avenue of introduction here.

Virtually all reports of new locality records, at least in recent decades, remark that the species is noted in disturbed or mown roadsides, suggesting that transportation by vehicles or mowing equipment may be the culprits for spread along such avenues. This theory may be bolstered by first county reports in such locations as Gillespie, Fort Bend, and Kimble counties where the species was first noted in state parks, locations which attract vehicle and RV traffic from far-flung locations. Movement of mowing equipment by city, county, and state highway maintenance crews would seem like another obvious source of seed transport.

Links to Further Information:
https://plants.usda.gov/core/profile?symbol=HECR2
http://bonap.net/MapGallery/County/Hedypnois%20cretica.png
https://www.invasiveplantatlas.org/subject.html?sub=29943
https://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=4024

* IMPORTANT NOTE: All of this discussion of dispersal patterns and mechanisms is highly speculative since the timing and geographical array of new records is so heavily dependent on observer distribution and attention, aspects which are certainly not uniform nor exhaustive across the landscape.


Literature Cited

Aplaca, J. L. 2010. The Non-native Flora of Texas. M.S. thesis, Texas State Univ., San Marcos.

Bergman, C. M. 2017. The Vascular Flora of Lee County, Texas. Lundellia 20:60–114.

Correll, D. S. and M. C. Johnston. 1970. Manual of the Vascular Plants of Texas. Texas Research Foundation, Renner. 1881 p.

Diggs, G. M., Jr., B. L. Lipscomb and R. J. O'Kennon. 1999. Shinners and Mahler's Illustrated Flora of North-central Texas. Botanical Research Institute of Texas, Ft. Worth. 1626 pp

Hannick, V. C., J. N. Mink, J. R. Singhurst, and W. C. Holmes. 2013. Annotated checklist of the vascular flora of McLennan County, Texas. Phytoneuron 2013-29:1-37.

Hanson, C. G. and J. L. Mason. 1985. Bird seed aliens in Britain. Watsonia 15:237-252.

Hatch, S. L, K. N. Gandhi, and L. E. Brown. 1990. Checklist of the Vascular Plants of Texas. Texas Agr. Exp. Station, College Station, TX. MP-1655. 158 p.

Jones, F. B. 1977. Flora of the Texas Coastal Bend, 2nd ed. Rob & Bessie Welder Wildlife Foundation, Sinton, TX. 262 p.

Mason, C. T., Jr., R. K. Van Devender, and G.D. Starr. 1986. Notes on the Flora of Arizona VII. Desert Plants 8(1):38-40.

Munz, P. A., and D. D. Keck. 1959. A California Flora. Univ. of Calif. Press, Berkeley. 1681 p.

Robbins, W. W. 1940. Alien Plants Growing Without Cultivation in California. Univ. of Calif., Agr. Exper. Station, Berkeley. Bulletin 637.

Turner, B. L., H. Nichols, G. Denny and O. Doron. 2003. Atlas of the Vascular Plants of Texas. Two volumes. Sida Botanical Miscellany, Botanical Research Institute of Texas, Fort Worth. 888 pp.

USDA Natural Resource Conservation Service. PLANTS Database. Searchable online database at https://plants.sc.egov.usda.gov/core/profile?symbol=HECR2 [for Hedypnois cretica]. Accessed 23 May 2019.

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