Specimens of Ruppia from all eleven Nebraska counties in which it is known fall into two groups: R. occidentalis in alkaline Sandhills waters and R. maritima in saline waters of the Platte River Valley and Lancaster County. Ruppia occidentalis is distinguished by its more robust size; redspotted leaves and stems; terete, entire, obtuse leaves; 4-8(9) carpels; and by two elliptic white spots on ...

Rising atmospheric CO(2) often triggers the production of plant phenolics, including many that serve as herbivore deterrents, digestion reducers, antimicrobials, or ultraviolet sunscreens. Such responses are predicted by popular models of plant defense, especially resource availability models which link carbon availability to phenolic biosynthesis. CO(2) availability is also increasing in the o...

Non-native species introductions are widespread and can affect ecosystem functioning by altering the structure of food webs. Invading plants often modify habitat structure, which may affect the suitability of vegetation as refuge and could thus impact predator-prey dynamics. Yet little is known about how the replacement of native by non-native vegetation affects predator-prey dynamics. We hypot...

?????????????????????????????????????????????????????????????????????????.???????????????????????????????????.?????????????????????????????????????????????????4??????25?50?75?100 cm??????????Potamogeton malaianus?????Hydrilla verticillata?????Vallisneria natans??????Ceratophyllum demersum?????????????????????.??????1?????????????0.09%???0.09%???3.04%????20.87 mg/kg????10.7 mg/kg????326.67 mg/kg...