Earlier this month, we embarked on the third and final citizen science field trip for our GeelongPort #BlueCarbonArmy program, which aims to sample the biodiversity and carbon gains from saltmarsh restoration.
We couldn’t have been luckier with the weather – it was a beautiful, sunny spring day with just a slight breeze to keep us cool while we surveyed. Given that there may be seasonal changes to biodiversity in this dynamic ecosystem, it was fitting to take a moment and look at the colours on display from the expanses of glassworts, seablites and pigface growing in the restoration areas. We were treated to a sea of greens, reds, pinks and yellows.
October is a busy time for migratory shorebirds, and we were lucky to spot birds from the Calidris genus in a Restored 8+ survey area. We also recorded resident waders, red capped plovers (spotted in July and March) and some red kneed dotterels.
The bugs were also very much out and about. For the team surveying our “Snake Island” sites, they were surprised at just how many little wolf spiders and other crawling insects were to be found on the mostly unproductive salt ponds. The larger glassworts and saltbush in the restored sites were home to plenty of other spiders and flying insects. John and Louis from Bug Blitz once again did a fantastic job of demonstrating how to sample for invertebrates, and Louis is busy identifying all the specimens we collected.
Once again, we will be adding photos of the birds, bugs and plants we observed to iNaturalist – follow the October project to see what we’ve found.
As our citizen scientists can probably agree, sampling and observing species in the field can be hard work. Birds can be tricky to identify, as they may fly over a survey area too quickly to note all the identifying features. Many migratory shorebirds have very similar non-breeding plumage (feather colours) when they visit our shores.
While bird surveys and direct sampling of habitats for invertebrates can give us a good snapshot of what is out in the saltmarsh at different times of the year, we need to acknowledge the limitations of these data sets. We can miss especially cryptic (well-hidden) species, species that are hard to identify visually, or species that are easily startled and move away from a survey site as soon as observers approach. Sometimes, if a species exists at a location but in really low numbers, they can easily be left out of a survey (especially if these one or two individuals happen to be just outside the survey area at the time it is being conducted).
That’s where eDNA comes in. Environmental DNA, or eDNA for short, is DNA collected from samples of soil, water, or air, rather than from an individual organism. As organisms shed a little of their DNA through interactions with the environment, we can use molecular analysis to detect species that occur in this environment without needing to capture or physically observe them. On this trip, participants assisted with eDNA sampling at each of the study sites – and we’re excited to see what the results are.
The important thing to note is that when it comes to quantifying the biodiversity found in different habitats and different times of the year, all of these methods help piece together the picture. For example, eDNA can’t tell us what the animals were doing (e.g. foraging, nesting), and DNA does break down over time, so a single sampling can’t tell us everything. Seasonal sampling for eDNA can help confirm changes in the kinds of species inhabiting the restored saltmarshes throughout the year. But, by combining it with traditional methods of observation we can get a more complete idea of what lives in these habitats (either permanently or temporarily), and whether time since restoration is having an impact on how and when they use these areas.
We’ve loved seeing the enthusiasm of our participants on each field trip, who were keen to help out with a variety of survey techniques (and no one seemed to mind muddying their hands and boots!). For everyone that took part, we are busy collating and analysing your data and hope to share with you some results soon.
Thank you very much for diving into this research program and helping us quantify the benefits of restoring what are all too often overlooked and poorly managed coastal ecosystems. We hope you’ve enjoyed these days in the field, learning a little more about your local environment, and getting a taste for blue carbon and biodiversity monitoring!