Citation:

TALLENT-HALSELL, N. G. AND L. WALKER. THE EFFECTS OF LIGHT AND NUTRIENTS ON AN INVASIVE BUDDLEJA DAVIDII AND A NATIVE GRISELINIA LITTORALIS. Presented at Ecological Society of American/Society of Ecological Restoration Joint Meeting, San Jose, CO, August 05, 2007.

Impact/Purpose:

The primary objectives of this research are to:

Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;

Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;

Develop and validate multivariate models based on quantification studies;

Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;

Complete an initial draft (potentially web based) of a national landscape condition assessment.

This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.

Description:

Buddleja davidii (Family: Buddlejaceae), an aggressive, highly invasive, ornamental

shrub of Asian origin, may be suppressing slower-growing native species (e.g., Griselinia

littoralis; Family: Griseliniaceae) on New Zealand floodplains, thus altering successional

trajectories. This study sought to learn what effect Buddleja might have on a midsuccessional

species when different treatments of light and nutrients were applied.

Buddleja and Griselinia shoot relative growth rate and foliar N and P were significantly

greater when grown in the 27% light-level than in the 90 and 10% light levels. In

contrast, both species have reduced growth (Buddleja 97 and Griselinia 99 % less shoot

relative growth rate) and higher mortality in 10% light than those grown in the 27 and

90% light levels. These results suggest that both species are better suited for growth in a

mid-successional stand than at newly disturbed sites or under late-succession forest

canopy. Buddleja growth and foliar N and P were significantly less when grown with

another plant of equal or greater biomass regardless of species, while Griselinia growth

was adversely affected by the presence of Buddleja. These results suggest that

competition will suppress Buddleja growth. However, further investigation is needed to

determine the response of Buddleja to another like-sized species under field conditions.

Record Details: