A relatively poorly surveyed, mostly rural LGA containing the townships of Seymour and Kilmour and the bushland army training area at Puckapunyal.
|Interpretation of these figures|
|The data upon which this search are based
have been drawn from the 2007 edition of
Just-a-Minute Plants and
is a package developed by Viridans to provide high-accuracy and
easy-access information on plants and animals in Victoria.
The Just-a-Minute base data has been generated by taking the site-specific information from the Flora Information System (FIS) and Victorian Fauna Database (VFD) and summarizing it into a series of about 85,000 one-minute x one-minute grid cells (each about 2.7 km2 in area) which cover the 230,000 or so square kilometres of the state. This summary has been performed for two reasons. The first is to even out the data density for different areas of the state so that valid regional comparisons can be performed. The second is to speed up the process of searching and sub-setting the data into the HTML-based format presented here.
(Note: FIS and VFD data which is not site-specific - that is, the location of the record cannot be specified to a radius of less than about 1 km - has been left out of this analysis as it will not allow us to search small and irregularly-shaped areas with any degree of certainty. As a consequence it may be true that a search will turn up fewer species than are known for any given area but the species which are absent will not have been located to a high level of accuracy and as a consequence are not going to be easy to find. Examples of this may include the knowledge that certain species are known from geographically defined areas such as Wilsons Promontary or French Island or the Mornington Peninsula - each of which allows us to determine which LGA the record is from - but these records will not have found their way into the Just-a-Minute database.
Conservation Status is a measure of the differences between the actual and expected proportions of four species categories of conservation significance. The categories are Victorian Rare or Threatened Species (VROTS an internal DSE classification with no legislative backing), Australian Threatened Species (listed under the Commonwealth Environment Protection and Biodiversity Conservation Act EPBC), species listed under the Flora and Fauna Guarantee Act (FFG) and non-native species. For the first three groups actual proportions which are lower than the expected numbers will count as negatives and values greater than expected will count as positives. For the non-natives species the reverse will be true.
By their nature rare and threatened species will make up a small proportion of any local species list. As the area to be surveyed increases, however, the proportion of the species list made up by these plants or animals will increase. For example, species categorised as rare or threatened in Victoria make up about 45% of the state's native flora and 35% of its fauna. However, when we look at smaller areas, of 200-300 km2, that proportion generally drops to about 5-6%. It is important, therefore, when assessing the proportion of rare or threatened species to the total species list, to take into account both the size of the area and the intensity of the survey effort.
A low value for Conservation Status could mean that the area has been very disturbed and that much of the native vegetation has be removed, or that the data was collected by inexperienced biologists who simply missed, or were unable to identify the threatened species, or that the area is naturally low in threatened species.
Survey Effort is calculated from the proportion of grids that have any data at all and the number of grids with specific amounts of data. For example, if a search area has data recorded for more that 80% of its grids and most of these grids have a relatively high number of species recorded (e.g. greater than 50), then the survey effort in the area would be regarded as very high. Conversely if the total numbers of grids with data is less than 20% and most of these have only one or two species recorded then the survey effort would be regarded as very low. The qualitative descriptors are based on empirical analysis of the total Just-a-Minute databases.
Two general rules can be applied to interpreting these figures. One is that a well-surveyed area will have data recorded for most of the one-minute grids, even if the grid falls substantially on agricultural land. The other is that a well-surveyed one-minute grid, which supports at least some native vegetation, will generally have records for 150-200 species of plants (up to 400 species in some parts of the state) and 75-100 species of animals (up to 250) while a grid that falls substantially on agricultural land will commonly have records of 50 or more species of plants and 25 animals (significantly more in areas with remnant roadside vegetation). We take a the lowest figures of 50 and 25 species as the minimum for a well-surveyed grid.
Any descriptor for Survey Effort which is lower than high should be interpreted as insufficient to make detailed land-management and conservation decisions. Under these circumstances a professional ecological survey would need to be executed before proceeding with such decisions.
Species Composition is a measure of the differences between the actual and expected proportions of six plant groups and four animal groups. These groups are, for plants, eucalypts, wattles, orchids, grasses, composites and peas, and for animals, mammals, birds, reptiles and frogs.
The plant groups have been chosen because they are found throughout the state, in all ecosystems, and are each represented by a large number of species. Additional considerations are that the eucalypts and wattles are usually the most regularly recorded genera (which accounts for their larger than normal proportions in less intensively conducted surveys), orchids are often given special status by field naturalists and others in conservation assessments (there is a higher proportion of rare or threatened orchids than most other groups - 60%), and finally, grasses, peas and composites are the largest and most widespread plant families in Victoria (and in most temperate parts of the world). The relative proportions of these plant groups in healthy vegetation across Victoria is remarkably stable irrespective of the size of the area surveyed, its geographic location and the intensity of the survey effort. As a consequence these groups offer a useful indicator of the health of local vegetation as well as the quality of any ecological surveys.
Records for birds are invariably the most numerous for fauna as most birds are diurnal, have distinctive calls, do not generally require trapping for identification and there are many excellent field guides. Mammals, reptiles and frogs, on the other hand, all require specialist equipment for trapping and collection, are often difficult to identify, many are nocturnal and some are dangerous. As a consequence in most less intensively surveyed areas the proportions of birds to the total fauna list will be higher than for well-surveyed areas.
A high value for Species Composition Status is difficult to interpret. It may mean that the ecosystems in the area have been significantly disturbed so that some groups have been artificially increased or decreased. It may mean that the survey work carried out so far has ignored some plant or animal groups in favour of others; for example, grasses and many small composites are notoriously difficult to identify especially if flowering material is unavailable and frog, reptile and mammal survey is more time consuming than that for birds. In addition, many species of orchid, grass and composite are only visible or identifiable for short periods of the year, many birds are migratory, and reptiles and frogs are less active in winter. If these species were ignored in surveys the proportions of the ten target groups may vary considerably. Alternatively the ecosystems which dominate the search area may simply be very different from the state average; for example areas where coastal or inland salt marshes are abundant, areas with largely treeless grasslands, or areas where the orchid (heathlands) or reptile (mallee) diversity is unusually high.
The Summarized Data provides you with 22 sets of figures which reflect the actual number of species recorded from the survey area and the relative proportions of important plant and animal groups, as well as the expected number and proportions of species in an area of this size. The expected figures are drawn from the entire Just-a-Minute database which has been assessed at a range of levels of resolution and sampling intensity. They represent the average numbers one would expect to find in areas of vegetated and agricultural country across Victoria. The actual figures will, of course, vary from place to place and it will be expected that surveys in the drier country of the north-west will have fewer species (but a higher proportion of reptiles), surveys in eastern Victoria, Wilsons Promontory and the Grampians will have more native plants and a lower proportion of non-natives, surveys near the coast will have more birds (if carried out while migrants are in the area).
Vegetation and Bioregions shows the number of Ecological Vegetation Classes (EVC) that are probably in the LGA as well as the Bioregions that it encompasses. These two terms are units of land devised by the Department of Sustainability and Environment (DSE) to provide regional and local structures for ecosystem management. There are 28 bioregions which are currently accepted for Victoria and about 250 EVCs. EVCs cross bioregion boundaries and when they do they are labelled as different entities. For example, the Sub-alpine Grasslands EVC is found in four bioregions (Highlands Northern Fall, Highlands Southern Fall, East Gippsland Uplands and Victorian Alps) and is accordingly assigned bio-EVC names which combine the two sources. All up there are over 1200 bio-EVCs in Victoria, In this assessment, however, the number refers to the base-level EVC and ignores the subcategories.