Step 2. Which plant species will be sustainable for the proposed revegetation site in the future?
This section is a basic guide on how to assess the sustainability of plant species for revegetation projects as the climate continues to change. Checking species distribution maps and scatterplots can provide an indication of the climatic tolerance of species. This information can also suggest if future climatic changes may put a species at or beyond its limits of climatic tolerance.
The Atlas of Living Australia (ALA) is an extremely useful resource for visualizing species’ distributions in relation to different environmental, including climatic, variables (see15 or http://www.ala.org.au/wp-content/uploads/2015/02/Belbin_Spatial-Portal-Manual.pdf for examples). We note that some browsers function better than others for some of the ALA functions. Firefox and Chrome tend to give consistent results across all platforms. Occurrence records in the ALA have not been checked for accuracy (i.e. ‘cleaned’) and this has implications for output and analysis (see Step 2.2 (3) and Box 4). For NSW plants, www.nswnichefinder.net uses only cleaned data from the Australia Virtual Herbarium and also performs some of the functions detailed below.
2.1 List the species currently recorded at the site:
- Go to the ALA main menu http://www.ala.org.au.
- Under the ‘Explore by location’ option, click on ‘location’, and enter the latitude and longitude of the site or the site’s name into the search bar. As an example, enter 36.01S, 146.95E, for a site north of Albury. The ‘Explore your area’ page shows the location of the site on a satellite map and lists the species.
Download http://www.ala.org.au/education-resources/teachers-guides-2/ Guide #1 for screen shots to assist with this step
- Further information on particular species can be obtained by clicking on a species of interest from the list, e.g. Eucalyptus melliodora; a map of occurrences of that species in the target area appears. Click on ‘Species profile’ to access summary information about the species or the ‘List of records’ for more information about the record.
2.2 Map the current distribution of the species:
- Go to the main ALA menu http://www.ala.org.au and under ‘Mapping & analysis’ section click on ‘Spatial Portal’.
- Select ‘Add to map | Species’ and enter the species name e.g. ‘Eucalyptus melliodora’
Download http://www.ala.org.au/education-resources/teachers-guides-2/ Guide #2 for screenshots to assist with this step and for detailed instructions, including how to view two species at the same time
- Using the example of E. melliodora, the species occurrence map (Figure 3) shows that the species has a wide distribution from Victoria to the Gladstone region in Queensland, and also occurs in New Zealand. To check that any ‘outliers’ are credible records, click on that occurrence dot and then select ‘Full record | View details’ to display detailed information about the record. If you are not confident that the record is credible, the record can be removed (see Box 4). There is some value in leaving in cultivated locations, and locations where the species has naturalized or has been planted overseas (especially eucalypts16) because this gives some indication of the thermal tolerance of the species. However, these records should not be used to indicate rainfall requirements because the plants may be artificially watered.
Cleaning the data is an important step
To remove an occurrence record in the ALA, click on the point on the occurrence map – an ‘Occurrence information’ box appears. Click in the ‘Assign record to ad hoc group’ option. Click on the X at the top of the box to exit. On the left of the screen, click on the ‘Add in/out layers to map’ option within ‘Ad hoc selection’. The map is revised with the selected point in a different colour (in the distribution map below, the most northerly record is now a different colour). At the top left of
the screen (see red arrow on the screenshot below), you have the choice of analysing the data (e.g. scatterplot) with the point removed (the ‘out’ group) or with the point retained (the ‘in’ group).
Alternatively, if there is a group of points that you want to exclude, click on ‘Add to map’ and then ‘Areas’. Select ‘Draw polygon’ and draw a polygon around the points you want to include. A new map with only those points is then available.
2.3 Add the revegetation site to species’ distribution map and climate envelope
2.3.1 Add the location of the revegetation site to the distribution map
The location of the revegetation site can be added to the distribution map but this step requires a log in to import the site’s decimal latitude and longitude (see https://www.ala.org.au/spatial-portal-help/import-or-upload-points/). However, sometimes simply viewing the species distribution is all that is required to visually assess if the species is likely to have the adaptive potential for a wide range of climatic conditions and thus a suitable candidate for the proposed revegetation site. For instance, if the proposed site corresponds to the hottest or driest range boundary of a particular species, the species may not persist at that site in the future. More detailed analysis of the climate envelope that the target species currently occupies and its likely persistence under future climates can be viewed via a scatterplot (see below).
2.3.2 Prepare a scatterplot to show the species’ current climate envelope
To find the decimal latitude and longitude and current environmental values (e.g. mean annual temperature and annual precipitation) of the proposed planting site:
- Go to http://www.ala.org.au, and under ‘Mapping & Analysis’ click on ‘Spatial Portal’.
- Click on ‘Add to map | Layers’. Go to “Add from search” box, type in ‘Bio12’ and click on ‘Precipitation – annual (Bio12)’ when it appears from the drop down menu, and ‘1 layer selected’ will appear at the bottom. Go back to the box and type in ‘Bio01’ and click on ‘Temperature – annual mean (Bio01)’ and ‘2 layers selected’ appears. Click next.
- Decrease opacity to improve map readability. Double click on map to get closer to the site. On the bottom right hand side of the screen, as you hover over the site, the values will appear. Write the values down, close this window and return to the window with the distribution map (Step 2.2).
To add the proposed revegetation site to the scatterplot:
- Go to ‘Add to map | Areas’ (see Figure 4). Under ‘Searching’, click ‘Create radius from point | Next’
- Enter the lat/long for your site (e.g. 146.95 for longitude and -36.01 for latitude) and then select radius (e.g. 3 km) | Next. (Distances <3 km may be difficult to see on the map).
- In the top left hand corner, a heading for a new map called ’My area’ will appear (Figure 4).
To produce a scatterplot:
- Go to ‘Tools | Scatterplot’.
- Step 1: select ‘Current extent’ (select ‘Next’ after each step);Step 2: select the species (e.g. Eucalyptus melliodora);Step 3: ‘My area’;Step 4: temperature and precipitation will probably be the most useful climate variables for plants. In this example, type ‘Bio12’ into the 2nd box (Add from search) and click on ‘Precipitation – annual (Bio12)’ when it appears in the drop down menu. Go back to the box and type in ‘Bio01’ and click on ‘Temperature – annual mean (Bio01)’ when it appears and 2 layers will be selected;
Steps 5 and 6: leave as defaults.
We recommend that other variables, such as annual maximum mean temperature and moisture availability, are also analysed for consideration of extreme weather events.
A worked example of a scatterplot with screenshots, using a different species, is available at http://www.ala.org.au/spatial-portal-help/scatterplot/
- The scatterplot shows the climate envelope the species currently occupies. In this example, the majority of the occurrences of E. melliodora are between ~12° and 17.5°C mean annual temperature and 500–1000 mm precipitation (Figure 5). The graph also shows the position of the proposed revegetation site within the climate envelope (i.e. 14.5°C and 730 mm). N.B. using the mouse we can select locations on the scatterplot and they will appear as red circles on the species occurrence map.
2.4 Apply the climate projections to the scatterplot to assess the species’ sustainability under future climate
- Refer to the future climate projections for the region of interest. Using the example of E. melliodoraand the Albury site (Step 1, Box 3) (http://www.climatechangeinaustralia.gov.au/en/publications-library/cluster-reports/), a mean warming of 2.7–4.5°C in 2080–2099 (using RCP8.5), with rainfall projected to vary between seasons i.e. -40% to +5% in winter is projected.
- Compare the climate projections with the information derived from points 2 to 4, particularly the scatterplot. For E. melliodora at the Albury site, by the end of the century, the projected rise in mean annual temperature and a 30% decline in annual precipitation is likely to put conditions at the Albury site at the outer limits of those that are currently experienced within the natural distribution of the species (Figure 3). Under those conditions, E. melliodora may not be a suitable species and monitoring of distribution changes would be advisable.
2.5 Consider alternatives if local species are unlikely to be sustainable
After completing Steps 2 and 3, if the persistence of existing species is doubtful under changing climatic conditions, plants from outside the local area may need to be considered for the proposed revegetation site. This is particularly important for key species such as those needed to recreate functioning ecosystems. There are many factors to consider if species from outside the local area are included in a planting list and in addition to industry standards (e.g. the SERA Standards for the Practice of Ecological Restoration in Australia), consideration should be given to factors such as:
- Is there a risk of the species becoming invasive?
- Can the species disperse or migrate naturally to the proposed revegetation site?
- Are there any common species at the proposed revegetation site and an analogue town (Box 5)?
- Are the soil types compatible?
- Have any ‘new’ species already migrated to the proposed revegetation site?
To view a list of species that are currently present in locations with current climates similar to those that a selected location may experience in the future (Box 5):
Go to: http://www.ala.org.au | Species by location, and follow the instructions set out in Step 2.1.
2.6 Model future distributions for species unlikely to survive without assistance?
Species with limited climatic tolerances that cannot adapt to a changing climate insitu or disperse naturally to more favourable climes will be vulnerable to population decline and potentially even extinction. Planning should include the translocation of these species to cooler and wetter (if applicable) locations outside their current range, if these locations exist. More detailed climate analysis can be undertaken in ALA using MaxEnt software. Species’ potential distributions are modelled using several environmental layers. This function is not detailed here and we recommend further reading on MaxEnt http://www.cs.princeton.edu/~schapire/maxent/ and examples of modelling17 before undertaking this step.
A NOTE OF CAUTION When using tools that only evaluate climate parameters, other determinants of past and future distribution such as soil, aspect, topography and interactions with other species (such as competitors and herbivores) should also be considered. Helpful websites include http://spatial.ala.org.au/ (Add to map | layers) and for NSW plant species, www.nswnichefinder.net
Imagining future changes in vegetation communities
As the climate changes, some plant species may become increasingly unsuited to a particular local site. Changes in the population sizes and distributions of individual species will progressively lead to changes in the characteristics of vegetation communities. For example, shrubby vegetation may progressively replace grasslands in some areas. The Climate analogues tool, available at CSIRO and Bureau of Meteorology Climate projections for Australia website (http://www.climatechangeinaustralia.gov.au/en/) provides a useful way of envisioning the magnitude of potential vegetation change at a site under a particular future climate. In brief, the tool is used to find locations in Australia with current climates similar to those that a selected location may experience in the future.
The website provides detailed instructions on how to use this tool, but here we provide an example. Let us suppose that a revegetation project for a site in the vicinity of Melbourne is being planned and we wish to envision what type of vegetation that site might support in the period 2040 to 2059:
- Go to http://www.climatechangeinaustralia.gov.au/en/climate-projections/climate-analogues/analogues-explorer/
- Either select Melbourne from the dropdown box (left side, bottom of map) or click on Melbourne on the map.
- Use either the ‘Configure data’ or ‘Preset scenarios’ option. To use the preset option, select the cluster Melbourne belongs to (http://www.climatechangeinaustralia.gov.au/en/climate-projections/about/modelling-choices-and-methodology/regionalisation-schemes/); the emissions scenario (we use the highest, RCP8.5, see Box 2); time period and the future climate description (see Figure 6).
- The temperature and rainfall ranges projected under those parameters then appear under ‘Configure data’, and on the map, arrows point to analogue towns (a list of towns appears below the preset function).
- Under the parameters selected here, in 2050, Melbourne is projected to have the climate conditions currently experienced in Cootamundra, Nuriootpa, Wangaratta, Keith, Clare, Corowa, Shepparton, Jerramungup, Wagga Wagga, Bordertown, Port Lincoln, Naracoorte, Esperance, Adelaide, Kojonup, and Young. This list of analogue towns will change, depending on the variables that you use.
- By researching the vegetation types typical of these sites currently, the potential for future vegetation changes at the Melbourne revegetation site of interest can be envisioned.
The caveat to bear in mind is that this tool is a potential source of ideas, rather than a method to simply obtain a list of species that should be planted at the site in question. The tool does not match other potentially important aspects of local climate (e.g. frost days, microclimates) or soil types. However, species from those areas may be appropriate if factors other than climate change are also considered to determine the suitability of species selection. Step 2.5 outlines how to find a list of species from the towns identified in the analogue tool, but we recommend firstly assessing which of the existing species will be sustainable in the future (Steps 2.1–2.4).
The ANPC is proud to be hosting ‘Climate-ready revegetation – a guide for natural resource managers’ on behalf of the authors. However its content has not yet been formally endorsed as ANPC policy. The ANPC suggests that any user of the guide should carefully consider its appropriateness to their particular circumstances. The field of climate-anticipatory revegetation is still developing, is locally contingent, and should be considered in conjunction with established best practice