Unkown tag : NAVIGATE Design - Species and provenance selection

Species and provenance selection

Using the Florabank tools

Florabank has developed a tool to help you select the appropriate species for your site and your purpose. The Species Navigator is a tool that we have developed for common revegetation species in Queensland, central Victoria, the Western Australian wheatbelt, the ACT and surrounding areas and the Northern Agricultural region of South Australia. Many of the species occur outside these areas, so the key will be useful throughout southern and eastern Australia. We will continue to add species to the tool. Using the tool, you can select species for a particular geographic area (NRM region, IBRA region), for site conditions (climate, soil, topography), for particular uses (timber, amenity, shelter) or for difficult site conditions (saline, alkaline, exposed). The key will also tell you about any variation within a species that you need to consider before choosing provenances.

In the coming weeks you will also be able to use the Florabank Site Descriptor Tool  to help you describe the site were you will be planting. This directs you to web-sites and publications to help you describe your soil, climate, vegetation community and landform. With this information you will be better able to use the Species Navigatoror to describe your site to a nursery or seed bank so they can help you select appropriate species.

Species Selection

It is generally accepted that for revegetation for conservation purposes, it is best to choose species that occur locally. Such species are well adapted to the environmental conditions of the site, and their pollinators, predators, symbionts and dependent wildlife are present. There are likely to be sources of seed available locally.

There are situations where it is appropriate to use non-local species for conservation plantings. These include:

  1. Where the planting is part of a larger landscape scale planting where function and spatial distribution are more important than composition,
  2. Where an economic return is required to achieve large scale revegetation (such as farm forestry, or saltbush),
  3. Where the environment has changed to the extent that some local species can no longer survive (salinity, altered soil structure, waterlogging, frost),
  4. Where a species is needed to modify the environment so local species can thrive (for example where a salt tolerant species is used to lower water tables to reduce soil salinity).

Human-induced climate change is likely to alter the environment for plant growth and must be taken into account when considering species selection. Many of the trees that we plant will live for centuries, during which time changing climates are likely to affect their ability to survive, breed and set seed. It is appropriate to consider future climates when selecting the species we use in revegetation. Some species have wide climatic tolerances while others will only tolerate a narrow range of rainfall and temperature (Jovanovic & Booth, 2002). In practice however, it will not be necessary to guess about new species for our restoration sites; rather, to select the most appropriate genetic material below the species level. 

The Department of Climate Change has published a primer for regional NRM bodies on climate change, (Campbell, 2008).  It looks at potential climate change impacts for issues like salinity, native vegetation, water, weeds, ferals and fire, and aims to assist regional NRM bodies to think about how to handle climate change, including issues in relation to revegetation projects.  This document can be downloaded here.  For plant species selection, they recommend using local species grown from seed with good genetic diversity.  Broadhurst (2007) provides information about the importance of using seed of high genetic quality for revegetation projects.  

Provenance selection

For years revegetators have followed the local provenance mantra, for the same reasons that we select local species. This is principally about getting material that is adapted to local conditions, but also arises out of concerns about genetic pollution.

Provenance is a forestry term that means the location where the seed was collected for use in revegetation. Morphological and physiological features of different provenances are often different. For example, Acacia melanoxylon (blackwood) exhibits provenance variation in wood density, heartwood distribution, stem form and frost and drought tolerance (Searle, 1996). This is known as adaptive variation. Conservation revegetators believe that seed should be collected as close to the revegetation site as possible to account for adaptive variation. Distance is, however, a poor indicator of adaptive variation as proximate sites can have greater difference in environmental conditions than widely separated sites. This document from the Glenelg-Hopkins CMA outlines why choosing seed of local provenance is so important.

In practice, local provenance has been interpreted as 'the closest available seed to the revegetation site', resulting in seed from very different sites being used. More importantly, it has resulted in seed being collected from small, inbred populations, with severe consequences for the resulting revegetation. You can read about the possible consequences of using this type of seed in Broadhurst (2007)  and in other provenance references on the Florabank website.

Florabank now recommends that provenance be considered in the following manner when collecting seed for revegetation:

  1. Get the taxonomy right first
    Make sure you are dealing with the same species/subsp/variety or cultivar
  2. Get the physical and genetic quality right
    Collect from 20-100 plants.
     - Collect from plants at least 3 plant-heights apart
  3. Only collect from large populations or pool multiple collections from smaller populations
  4. Store seed under best conditions from collection right through to use
  5. Match the site conditions
     - Soil (texture and origin)
     - Altitude
     - Aspect
     - Slope position
     - Latitude (use bioregions as the boundary)

Then worry about proximity between collection and revegetation sites

Between the patch and the landscape scale, there will be a spectrum of options open to the revegetator. We need to look now at the methods and techniques appropriate for this range of revegetation options.

Next Revegetation techniques

Return to contents