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GRASSES AS INVASIVE SPECIES Clay Antieau, MS, Phc Botanist, Horticulturist, Environmental Educator

GRASSES AS INVASIVE SPECIES Clay Antieau, MS, Phc Botanist, Horticulturist, Environmental Educator

GRASSES AS INVASIVE Clay Antieau, MS, PhC Botanist, Horticulturist, Environmental Educator

WFCA Eighth Western Native Conference November 2019 THE GRASS FAMILY () • Genera : 700 – 800 • Species: 7,500 – 11,000 (4th largest) • Comparable in size to Aves (); ~ twice as large as Mammalia; half the size of Orchid or Aster families • First appeared in pollen record 55 – 70 mya (Paleocene) • Only angiosperm family found natively on all seven continents (Deschampsia Antarctica) • Includes cereal crops (forage, food, sugar, beer...); many ecological dominants • All major civilizations developed around cultivated grasses ( to Middle East to New World) Among the World’s Worst Invasives: Grasses • (cogon grass) • australis (common ) • Phalaris arundinacea (reed canarygrass) • Sorghum halepense (Johnson grass) • species and hybrids (cordgrasses) • species and hybrids (pampas grass) • donax (giant reed) • Microstegium vimineum (Japanese stilt grass) • tectorum (cheat) • Taeniatherum caput-medusae (medusahead) • dactylon (Bermuda grass) • reynaudiana (silk reed) Important North American Invasive Grasses (adapted from www.fs.fed.us/database/feis) cylindricus (goat grass) curvula (weeping lovegrass) Aegilops triuncialis (barbed goat grass) Eragrostis lehmanniana (Lehmann love desertorum (desert grass) grass) Elytrigia repens (quack grass) (crested wheat arundinacea (tall fescue) grass) Imperata cylindrica (cogon grass) arenaria (European Microstegium vimineum (Japanese stilt beachgrass) grass) Arrhenatherum elatius (tall oatgrass) Oplismenus undulatifolius (wavyleaf (giant reed) basket grass) sylvaticum (false Pennisetum setaceum (fountain grass) brome) Phalaris arundinacea (reed Bromus hordeaceus (soft chess) canarygrass) Bromus inermis (smooth brome) Phalaris aquatica (Harding grass) Bromus japonicus (Japanese brome) pratensis (Kentucky bluegrass) Bromus tectorum (cheat) Ripidium ravennae (ravenna grass) Cortaderia jubatua(pampas grass) Sorghum halepense (Johnson grass) (Bermuda grass) Spartina alterniflora (smooth cordgrass) Dactylis glomerata (orchard grass) Taeniatherum caput-medusae Echinochloa crus-galli (barnyard grass) (medusahead) Cogon grass (Imperata cylindrica) : > 60% of total biomass (40 tons/ac); up to 4 feet deep

Cogon grass (Imperata cylindrica) • Infests more than 500 million acres worldwide; every continent except Antarctica; expanding…. • USA introductions: accidental (crate packing) [1911, Mobile (Grand Bay), AL] and intentional (forage) (1921 MS; 1930 FL) Cogon grass (Imperata cylindrica)

Ornamental cultivar ‘Red Baron’ can revert back to the wild form and cause infestations.

Japanese stilt grass (Microstegium vimineum) Chris Evans, Illinois Wildlife Action Plan, Bugwood.org

Giant reed (Arundo donax), Sabino Canyon, AZ photo by Mark Hengesbaugh (Ventenata dubia) •Annual grass, similar to cheat (Bromus tectorum) in habit, , ecology •Formerly in Spokane, Yakima, Klickitat counties; now in Kittitas, Skamania, King, Cowlitz counties

photos by Matt Lavin Slender false brome (Brachypodium sylvaticum) Oregon, , Ontario Slender false brome (Brachypodium sylvaticum) in Oregon as of January 23, 2007

Estimates suggest infestation of at least 10,000 acres California Valley and Foothill California Valley and Foothill Ecosystem resembled PNW perennial bunchgrass Grassland Ecosystem…GONE! ecosystems.

THEN: Dominated by Stipa pulchra; S. cernua, Danthonia californica, Festuca californica, Sitanion jubatum, Elymus glaucus, , etc.

NOW: 1)introduction of Mediterranean annual grasses and forbs (Bromus, Hordeum, Avena, , Briza, Brachypodium…..) 2) 3)drought 4)severe wildfire

--human-mediated disturbance climax vegetation (“disclimax”)…. permanent, incapable of returning to previous climax vegetation of perennial bunchgrass otherwise expected for regional climate and soils = novel ecosystem Bromus, , Vulpia California

Brachypodium California INVASIVE GRASSES COMPROMISE ECOSYSTEM HEALTH AND INTEGRITY Altered Key Ecosystem Processes and Services include: • nutrient cycling and carbon cycling [Aegilops triuncialis (Drenovsky and Batten 2007)] • sediment erosion and deposition rates (spartina; giant reed) • disturbance intensities and frequencies [cheat (reduces fire cycle from 60–110 yrs to 3–5 yrs); medusahead; cogongrass (max temp 856º F)] • evapotranspiration, water cycling, hydroperiods (reed canarygrass; giant reed; cogongrass) • soil chemistry; soil biological processes (velvet grass) • primary productivity (ryegrass) • genetic integrity (bromes; wheatgrasses) • resilience to disturbance (incl. biol. invasions) (bromes; cogongrass) • habitat availability for native /animals/other organisms (reed canarygrass; quackgrass; cogongrass; Japanese stiltgrass; tall fescue…) • and associated food web interactions/characteristics Apical Meristems Intercalary Meristems WHY CAN GRASSES BE SO INVASIVE?? Simple modular growth form giant reed (Arundo donax) (phytomer concept: repeated building blocks containing fixed regions of cell division and origins of differentiation; basic unit of growth): node, internode, sheath, blade, and axillary bud; intercalary meristems at bases of blade, sheath and internode. Diversity derives from myriad modified versions of this basic, simple body plan.

annual bluegrass (Poa annua) WHY CAN GRASSES BE SO INVASIVE?? Wind pollinated or apomictic; highly reduced (inexpensive) floral and fruit structures; efficient wind, water, and animal (human) dispersal; extended seed dormancy: extraordinary capacity for sexual reproduction pratensis: 1,152,000 /lb vs Trifolium repens: 768,000 seeds/lb

Bromus tectorum: 400 lbs/ac vs 200-300 lbs/ac for cool season grasses field corn 3,000 seeds/lb

hairy vetch 16,000 seeds/lb

tall fescue Bermuda grass seeds (hulled) 227,000 seeds/lb 2,071,000 seeds/lb WHY CAN GRASSES BE SO INVASIVE?? Simple modular growth form (phytomer concept: basic unit of growth): node, internode, sheath, blade, and axillary bud; intercalary meristems at bases of blade, sheath and internode. Diversity from myriad modified versions of this basic body plan. Wind pollinated or apomictic; highly reduced (inexpensive) floral and fruit structures; efficient wind, water, and animal (human) seed dispersal; extended seed dormancy (many, not all). Generally do not produce secondary toxic compounds (glycosides, alkaloids, cyanogenics, etc) and instead avoid/tolerate through morphological and anatomical mechanisms (but see allelochemicals and endophytic fungi, below).

= extraordinary capacity for vegetative growth (tillers, stolons, rhizomes, bulbils, corms, fibrous ) and sexual reproduction…. PHOTOSYNTHETIC APPARATUS

C3: mesophyll is C4: coordinated anatomical and physiological loosely packed; bundle features concentrate CO2 around the C3 sheath cells lack photosynthetic machinery through use of a solar- chloroplast. powered biochemical cycle; mesophyll is tightly packed and radiately arranged; bundle sheath cells

with chloroplasts. PEP shuttles CO2 to bundle sheath cells. 3% of species (C4) account for ~25% of terrestrial photosynthesis. GRASSES ARE PRODUCTIVE Mollisols: Soils formed under prairie or grassland vegetation; grasses add abundant raw organic matter to the soil, mostly by in situ death.

More than 25% of the USA land area is covered by Mollisols, fertile soils now used predominantly for agriculture.

Zedler. U. WI Arboretum Leaflet 15. Aboveground productivity, C:N ratios, and root:shoot ratios are higher, on average, in native

A Palouse-region soil profile, grasses > non-native grasses > ID native forbs. Abdala, Caldas, Haridasan, Eiten (1998). (Brazil) WHY CAN GRASSES BE SO INVASIVE?? Pre-adapted genotypes (~11,000 species World-wide!)

Rapid evolutionary capacity (post-immigration evolution and microevolution) [Novack and Mack (2005): founder effects but high intra-population diversity from multiple introductions and novel genotypes; Longland and Ashleu 2007: evidence for local adaptation]; rapid speciation; niche specialization

Chromosomal Diversification: reduction, polyploidy, and hybridization are rampant (80% of all grasses are estimated to be polyploid); notable phenotypic plasticity within taxa (drought, cold, grazing, fire, soil fertility, soil moisture, climate change…)

Adaptation to drought and open (sunny) spaces and disturbance

Allelochemicals [Hogal and Sanford (2006): Bromus tectorum root extracts reduced growth of Hilaria jamesia by 60%; Lolium and Pinus ponderosa]

Endophytic fungi: asymptomatic fungi that occur intra- and inter-cellularly and produce secondary metabolites (alkaloids, indole–diterpenoids…)

Escape from biotic constraints FERAL CEREAL RYE (Secale cereale)

 Beginning in early 1960’s  Compared to cultivated

varieties (~60 generatons): ShareAlike 4.0 International (CC) • shattering • delayed flowering • more tillers • shorter (smaller ; thinner stems) • smaller, more seeds

Burger, J.C. and N.C. Ellstrand. 2014. Rapid evolutionary divergence of an invasive from its crop ancestor and evidence for local diversification. J. Systematics and Evolution 52 (6): 750–764. MANAGEMENT OPTIONS Cultural: prevention Physical: mowing, burning, grazing, hand-pulling mature stands, digging Biological: possibly some smuts/rusts or other fungi, or bacteria; cryptogamic soil crusts; biodiversity Chemical: Most useful in many situations Lack of selectivity is still a challenge The label is the law: read it and comply! Technical support from companies varies widely NON-SELECTIVE FOR GRASS CONTROL Active Trade Name Foliar Spot Foliar Broadcast Ingredient Treatment (%v/v) Roundup Pro, 1.5% (PA, AD) 1.5-2.5 pt/ac (MV) Aromatic Amino Accord 2% (MV) 4-7.5 pt/ac (PA, IC) Acid Synthesis Inhibitor (Group 2) Concentrate, 4% (AD, IC) 4-5 qt/ac (AD) Rodeo, generics 5-10% (PhyA) imazapyr Arsenal, Chopper, 2% (PhyA, IC) 3-4 pt/ac (AD) Branched-chain Polaris, Habitat 4-6 pt/ac (IC, PA) Amino Acid Synthesis Inhibitor 24 oz/ac (IC) (Group 9) Arsenal AC 1% (PhyA, IC, PA) 2-3 pt/ac (PA) hexazinone Velpar L 2 Gal/A (PhyA)

imazapic Plateau, generics 4 oz/ac (MV)

imazapic + Journey 10.7-16 oz/ac (MV) glyphosate

Arundo donax (AD); Imperata cylindrica (IC); Microstegium (MV); sinensis (MS); (PA); Phyllostachys aurea (PhyA). [Dr. Stephen F. Enloe, Auburn Univ, AL] POST-EMERGENT GRAMINICIDES: “FOPS” AND “DIMS” • Many herbicides provide pre- emergence control • A few post-emergent herbicides provide selective control of many grass species Active Ingredient Trade Name • Select/Envoy = only post- fenoxaprop-P Acclaim Extra emergent control for annual fluazifop Fusilade bluegrass clethodim Select, Envoy Plus • Short-term vegetative control sethoxydim Vantage, Poast • Very weak on large rhizomatous perennials; best on young, active • Fail to effectively kill rhizomes OPTIMAL TIMING OF HERBICIDES? • Treat infestations sooner than later to minimize acreage requiring treatment • Late summer/fall (when plants store energy belowground) is most effective window for treatment of aggressive perennials • However, growth at that time may be too tall to treat with ground equipment without additional treatment (integrated management: mowing) • Do not spray if targets are drought-stressed; if rainfall or heavy frost is forecast; when label says not to spray WHY DOESN’T A SINGLE TREATMENT NORMALLY ERADICATE? • Even short-lived seedbanks often have seed that delay emergence and escape treatment • area of shoot growth available for herbicide uptake not adequate to get enough material belowground • Dormant buds on rhizomes and lateral roots are not active transport sinks and escape treatment • Environmental conditions at time of treatment influence outcome imazapyr (Group 2) triazines (Groups 5, 6, 7) glyphosate (Group 9)

fops/dims

PARAQUAT-RESISTANT RYEGRASS IN GRAPES (Australian “double knock” system)

PARAQUAT OVERSPRAY DAMAGE IN SOY

• glyphosate application first (non-selective herbicide) • paraquat application two weeks later (quick-acting; contact herbicide) • developed specifically to minimize risk of developing glyphosate-resistant • 20 years of use has resulted in paraquat-resistant ryegrass THE FUTURE?  Grasses are important (but often overlooked) elements of our non- native flora and will continue to be so.

 Altered mechanisms of transport, increasing globalization, and continued plant importations will introduce many more to the PNW—including grasses.

 Pesticide usage will increase because of expanding and newly established invasive species, resulting in increased frequency of herbicide-resistance in those target species.

 Climate change will/is facilitating establishment and expansion of pathogens, pests, and invasive plants in new or previously unsuitable regions (e.g. cogon grass in SE US).

 Invasive plant species will respond to climate change; some of those changes will have significant ecological, economic, and weed management implications.

Hellmann, J., J. Byers, B. Bierwagen, and J. Dukes. 2008. Five potential consequences of climate change for invasive species. Conservation Biology 22(3):534-543. GRASSES AS INVASIVE SPECIES Clay Antieau, MS, PhC [email protected] 206-684-7413

cheat reed canarygrass Eastern Washington (WA State NWCB)

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