Harvest Mouse project news - Staffordshire Mammal Group

Thank you to Staffordshire Mammal Group (SMG) for sending us your harvest mouse data!

The data supplied to us by SMG has allowed us to convert this into baseline information on the presence of harvest mice in Staffordshire vice counties. This information  can then be used to identify tetrads that would best be surveyed over the next three years. The converted data helps to identify tetrads with:

• no presence or absence information – identification of potentially unsurveyed tetrads - see figure 1 below
• presence – so that repeat surveys should be conducted to see if presence persists - see figure 1 below
• persistence – the total number of years that a particular tetrad has had presences - see figure 2 below
• presence age – the number of years since last recorded presence to identify potentially out of date information, so that repeat survey can be conducted to see if presence persists - see figure 3 below
• connectivity of presence (index) – information on the average distance to the nearest 8 presence tetrads to identify fragmented populations, drawing attention to surrounding areas that could be reintroductions and future surveys - see figure 4 below

Please note that the information presented comes from data that was not collected through systematic or random surveys.

Send in your historic data and we can then supply you with a detailed map of the current situation of harvest mice in your county, based on existing data and the local mammal group historic data. Supplying your data means that future surveys can be carried out in the most efficient manner. Simply contact us at science@themammalsociety.org. 

Presence-absence

Simply a record of the tetrads where at least one HM has been recorded or where an absence has been recorded. If both have been recorded in a tetrad, i.e absence one year and presence previously or after, the tetrad is classified as presence.

Figure 1 Presence tetrads in red

 

 

 

Persistence

The number of years that at least one record of a HM has been recorded within each tetrad.

Figure 2 - Persistence

 

 

 

Age

The darker the red the more recent the record

Figure 3 - Age

 

 

 

 

Connectivity

The darker the red the lower the index score and the closer the tetrad is to surrounding presence tetrads.

Figure 4 - connectivity