Dactylis

Abstract: Natural habitats vary in the degree to which they are invaded by exotic species, but it is unclear whether they differ in the mechanisms underlying the spatial spread of a given exotic species. To compare the dynamics of invasion in highly invaded non- serpentine oak woodlands and less-invaded serpentine habitats, we used an historical ''ex- periment'' consisting of the introduction of several nonnative species for post-mining re- vegetation, supplemented by a pot experiment and a factorial field experiment. Three species showed significant declines in abundance on transects from revegetated zones into natural habitats, indicating that these species had spread into the natural habitats from revegetated zones. Dactylis glomerata and Trifolium hirtum were found up to 95 m into oak woodland, 35 m into serpentine meadows, and 0-25 m into serpentine seeps and chaparral, while Elytrigia pontica was found up to 45 m into serpentine seeps. The pot experiment showed that this pattern of distribution for Dactylis was not caused or limited by variation in soil properties. The field experiment showed that Dactylis invasion in both oak woodland and serpentine meadow habitats was limited by disturbance and seed supply. Dactylis success was negatively correlated with species richness in oak woodlands, but positively correlated with richness in serpentine meadows, suggesting that the relationships between diversity, invasion, and underlying habitat suitability differed between these hab- itats. Our results show that in harsh serpentine soils, the spread of recently introduced exotic species is slower than in more fertile and more invaded oak woodlands. However, distur- bance and propagule addition are equally important in promoting the spread of invaders in both environments.

Abstract: Graminoid Food and Feed Plants Maize Wheat Barley Oat Rye Rice Sorghum Forage Feed Plants Graminoid Brome Grass Cocksfoot Grass (Dactylis) Couch Grass (Agropyron) False Oatgrass (Arrenathium) Fescue Grass Sorghum Foxtail millet Molinia Panicum Grass Ryegrass Sweet Vernal Grass Timothy Grass (Phleum) Weed Johnsongrass Leguminaceae Alfalfa Red Clover Alsike Clover Crimson Clover Subterraneum Clover White Clover Birdsfoot Trefoil Vetch Lupins, Sweetclover Vegetables Solanaceae Pepper Tomato Eggplant Cruciferae Cabbage, Cauliflower, Brussels Sprouts Radish Turnip Liliaceae Onion Shallots, Leek, Garlic Cucurbitaceae Cucumber Melon, Watermelon, Squash, Courgette Leguminaceae Bean Pea Broad Bean Cowpea (Vigna) Umlelliferae Carrot Celery Parsnip Compositae Artichoke Endive Lettuce Chenopodaceae Spinach Industrial Peanut (Groundnut) Potato Tobacco Beet (Sugar) Sugarcane Sunflower Soybean Hop Fruit Trees Pome Apple Pear Quince Stone Plum Peach Apricot Cherry Almond Shell Walnut Hazelnut Chestnut Subtropical/Tropical Avocado Banana Citrus Fig Olive Palm Papaya Small Fruit Strawberry Rubus Raspberry Black Raspberry Ribes Gooseberry Black Currant Red Currant Vaccinium Blueberry Grape Vine Acronyms Symbols of Host Names Symbols of Non-Host Names and Symptoms Glossary Index Plant Legends (Pictures)