Citizen Science 2021 - Chew Card Results


Thank you to all those who were involved in the chew card campaign this year!



Link to the running pest abundance maps from 2017 to 2021. Please open this document to have a look at the maps and graphs generated from this year's campaign.


For a more in-depth look at most of our graphs and takes from this years campaign, as well as comparisons to previous years of data, please follow this link here.


For those of you who are new to the chew card campaign, our survey places out corflute cards impregnated with a non-toxic paste along survey lines in over 43 reserves in Kaipātiki. Rats, mice, possums, hedgehog, stoats and even other creatures like dogs and cats leave distinctive marks for us to identify. The results from the campaign allow an in-depth look at where pest control is needed the most, or where an increased diversity of traps is needed. We can also look at more interesting trends, such as how reserves are going over the whole 5 years of the campaign.


We also talk a lot about ‘relative abundance’ (RA). RA is a percentage composition of an organism (i.e a rat) relative to the total number of them in an area. It isn’t an exact count, but does give us a sound scientific base to monitor the prevalence of pests in an area. The LOWER the RA the better as it indicates little to none of that animal in the environment monitored. In general, restoration projects ultimately aim for 5% RA or lower. At this level, many forms of flora and fauna have the best chance for success.


Using these relative abundances we can create some graphs that show each individual pest species impact on different reserves.


 

Understanding ‘Relative Abundance’


Most of the results below are based on ‘Relative abundance’ which is a percentage composition of an organism of a particular kind, relative to the total number of organisms in the area. It isn’t an exact count, but does give us a sound scientific base to monitor the prevalence of pests in an area.

An example of this in action – is, if you place out 10 chew cards (at the proper spacing), and 7 of them come back with a rat chew, and 2 of them with mice chew, and none with possum chews your relative abundances would be: