The Lake SPI Index: A combination of the Native condition index (an indicator of the biodiversity and extent of native vegetation within a lake) and the Invasive impact index (an indicator of the degree of impact from invasive weed species). It provides an overall indicator of lake ecological condition. A high LakeSPI is desirable (0–20 percent, poor ecological condition; 20–50 percent, moderate ; 50–75 percent, high ecological; 75–100 percent, excellent). Non-vegetated lake status is associated with extreme lake eutrophication/deterioration.
Data calculation/treatment
This is counts of observations not lakes, as some lakes are repeated several times with different observations.
Limitations of the data
This data represents a small percentage of lakes in New Zealand, so we advise caution when interpreting results as they may not be representative of all lakes.
From the dataset Environmental Reporting: Lake Submerged Plant Index 1991–2019, this data was extracted:
Sheet: Sheet1
Range: B4:C8
Provided: 10 data points
Dataset originally released on:
April 07, 2020
Purpose of collection
Submerged plants are good indicators of the ecological quality of lakes. Because they are attached to the bed of lakes, submerged plants are easy to observe and identify, and they are unable to move away from environmental changes. The plant species found within lakes can tell us about their level of habitat degradation and exotic weed invasion.
Method of collection/Data provider
The lake submerged plant index (LakeSPI) uses observations of aquatic plants collected by trained divers, scuba divers, and snorkellers using standardised methods (de Winton et al, 2012).
Information on submerged plants’ structure and composition is used to calculate three indexes (de Winton et al, 2012).