| Zusammenfassung: | The control of introduced plants is frequently a demanding and expensive activity for wildlife managers. It can be difficult to suppress some well-established species, and control measures may harm native organisms. Reed canary grass (Phalaris arundinacea) is a common wetland invader that can dominate and greatly alter wetlands. To examine the relationship between this plant and native amphibians, we analyzed field survey data and quantified amphibian-plant relationships in constructed replicated experimental ponds. Surveys showed positive associations between reed canary grass and the abundance of 3 native amphibians in 62 natural and constructed urban and suburban ponds in Portland, Oregon. Experiments elucidated mechanisms whereby 2 native and 2 introduced plants influenced breeding habitat use and larval performance of the common native Pacific chorus frog (Pseudacris regilla). Males preferred to call from reed canary grass, and there was a strong trend for females to lay eggs on the invasive grass compared to other plants offered. Tadpoles had 7 times higher survival in reed canary grass. These patterns were likely due to the morphology of reed canary grass: it provides support for calling males, its leaves and shoots are of ideal size for oviposition, and its branching may provide effective refuges from predators. This study demonstrates that some introduced plants may be beneficial for some native amphibians. Improved understanding of the relationships between introduced plants and native wildlife can help guide management actions by recognizing that the control of introduced plants may not be a priority in all systems.
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