It is essential that surveys for threatened species are conducted at an appropriate time, as many plant and animal species are highly seasonal, or are more easily detected at certain times of year. Failure to survey at an appropriate time can lead to threatened species being missed at the planning stage. Some regulators may also have requirements for threatened species surveys at specific times of year.
Fauna
The appropriate time to survey for threatened fauna can depend on a range of factors, including breeding season, migratory activity, periods of dormancy, and seasonal activity patterns. Some fauna species are present and equally detectable all year round (e.g. many sessile species), while others may only be detectable for a short period.
Suitability of survey times for fauna are divided into three categories:
| Key |
Survey reliability |
| M |
Peak survey period: The best time of year to survey, when the species is most visible or easily captured/trapped. |
| M |
Potential survey period: The species is present and can be detected, but outside the peak period for detectability. |
| M |
Non-survey period: The species is either not present (e.g. migratory off-season) or present but not detectable (e.g. dormant stage in life cycle), or is insufficiently known. |
Flora
The appropriate time to survey for threatened flora can depend on a range of factors, including an annual life cycle, emergence at certain times (e.g. after fire), flowering period, and the appearance of certain vegetative features.
Suitability of survey times for flora are divided into four categories based on the degree of difficulty of detection (ie. how easy is it to find), and the ease of identification of specimens when they are found, as detailed below:
| Key |
Survey reliability |
| M |
Best time to survey: High probability of detection and identification
- Flowers or other easily-seen features present to aid detection.
- Specimens collected that are suitable as herbarium specimens (ie. with all features required for identification).
|
| M |
Potential time to survey: Moderate to high probability of detection and identification.
- Some herbarium specimens collected but not the period when most have been collected.
- Species can still be readily identified from less obvious features (e.g. from vegetative characteristics).
- Flowering months for Tasmania if flowers are needed for identification.
|
| M |
Poor time to survey: Low to moderate probability of detection and identification.
- Readily identifiable but hard to detect.
- Little information available on flowering time in Tasmania.
- Flowering period on mainland (preferably Victoria) if flowers are needed for identification.
|
| M |
Non-survey period: Low or negligible likelihood of detection and/or identification.
- No or few database observations made during this period.
|
Points to consider when surveying for plants:
- For widely distributed species, the collection date of database observations in the vicinity of a survey site or at a similar altitude can often narrow the most suitable time for detection and identification of the species at that site. If in doubt, seek expert advice.
- Habitat descriptions provided are generally broad, though where possible habitat niches where the species is most likely to be found are described. Any surveys should focus on and radiate out from such niches.
- Where possible, information is provided as to whether species are cryptic or only emerge at certain times (e.g. after fire, drought). For such species non-detection may not rule out an occurrence at the site).
- Bear in mind that some species may persist in the soil seed bank even when not present above ground (for such species non-detection may not rule out the occurrence at the site, particular if previously observed there).
- Many grasses are identified from fruits not flowers so the identification window will be later than the flowering time.
