Wetland internal vegetation condition

Find further information on the Conservation of Freshwater Ecosystem Values (CFEV) Program and its data at www.dpipwe.tas.gov.au/cfev.

Attribute data

TitleWetland (internal) vegetation condition

CustodianWater and Marine Resources Division, Department of Primary Industries, Parks, Water and Environment

CreatorGIS Unit, Information and Land Services Division, Department of Primary Industries and Water

DescriptionThe proportion of native vegetation within wetlands.

Input data

  1. CFEV modified TASVEG vegetation layer
  2. CFEV Wetlands spatial data

Lineage

An assessment of the naturalness of the vegetation inside wetlands was conducted using the CFEV TASVEG modified vegetation layer. The percentage area of natural* vegetation (from the TASVEG modified vegetation layer) within the wetland spatial unit was assigned to each wetland (specific rules outlined below). The wetland vegetation condition score ranged between 1 (100% native vegetation present or near-natural to natural condition) and 0 (0% native vegetation present or degraded condition).

* The natural class included natural non-vegetation TASVEG codes, such as water, rocks, etc. and the exotic (cultural) class included unnatural non-vegetation codes such as built-up areas. Appendix 12 of the CFEV Project Technical Report presents all of the TASVEG vegetation communities and their assigned group (i.e. either natural or exotic).

Data limitations

As per the TASVEG data set.

Date createdOctober 2004

Scale and coverage1:25 000; Statewide

Column headingWL_NVEG

Type of dataContinuous but also exists in a categorical format (see Table 1).

Number of classes4

Assigning values to ecosystem spatial units

The following rules were applied to calculate the wetland vegetation condition score (WL_NVEG) for each wetland spatial unit:

  1. Overlay the CFEV TASVEG modified vegetation layer with the CFEV wetland spatial data layer and calculate % area of the wetland polygon which is Natural.
  2. Assign calculated value as a proportion (0-1) to the wetland spatial unit.

The wetland spatial data layer had the continuous wetland vegetation condition data categorised according to Table 1. The categorical data was used for reporting and mapping purposes.

Table 1. Wetland vegetation condition categories for wetlands.

Category

Max to min values

1

0

2

>0 to 0.2

3

>0.2 to 0.8

4

>0.8 to 1

CFEV assessment framework hierarchy

  1. Wetlands>Statewide audit>Condition assessment>Naturalness score (WL_NSCORE)>Native vegetation condition (WL_NATVE)