How do we monitor large and continuous plant populations?

Primera sortida de la Xarxa de Voluntariat LIFE medCLIFFS

The first LIFE medCLIFFS volunteer field visit of the year 2023 took place on the past 4th of February. A total of 24 people participated in the visit, which was focused in monitoring the transect S1. This transect runs along the Blanes coastal path and starts right where the Mar i Murtra Botanical Garden ends.

The visit served to resolve one of common doubts among volunteers when they start to monitor a transect: what shall we do when a population is very large and continuously distributed?

We experienced in situ that, in this case, the best is to make a first register with a photo at the northern end, a photo in the middle, and a photo at the southern end, so that we have a reference of how large the population is and, in this way, we can monitor it the following year and see if it has increased and detect which species are expanding more rapidly.

Improvements in data collection

During the visit, volunteers were reminded about how to register for the iNaturalist project of the LIFE medCLIFFS Volunteer Network, which is the tool used to collect data for monitoring the transects, and which is only accessible by invitation. A new field has been added to this tool to show whether the quotations provided have already been checked and validated by the project technicians.

The participating volunteers were able to ask other questions that have arisen during the monitoring, such as: how to count specimens of Carpobrotus sp., with a ground cover habit, or Arundo donax, with many stems; how many times a year the monitoring should be carried out; how many photos should be taken for each register; or how many metres from the path we should monitor.

Suggestions were also collected from the volunteers to make data collection easier and more effective, such as automating the transect code field to avoid errors and differentiating the types of questions with colour codes so as not to get lost when taking notes in the field.

Observation of the escape of exotic flora

Transect S1 is located right next to the Mar i Murtra Botanical Garden and allowed us to observe first-hand how alien species often escape from botanical gardens and thrive on the cliffs. Following the coastal path, we also passed just below the gardens of houses next to the sea, where we could also see some alien plants escaping towards the cliffs.

The species observed were: Agave americana, Arundo donax, Carpobrotus sp., Chenopodium nutans, Dimorphoteca ecklonis, Drosanthemum floribundum, Kalanchoe ×houghtonii, Mesembryanthemum nodiflorum, Opuntia ficus-indica and Pittosporum tobira.

Senecio angulatus deserved an especial attention during the visit, since this species is occupying a large area in the transect and even is choking out native plants such as mastic (Pistacia lentiscus) or the Mediterranean buckthorn (Rhamnus alaternus).

Besides this, we were also able to observe that the invasive and alien plants can affect the Roccella phycopsis lichen, a species listed as vulnerable in the Catalogue of Threatened Flora of Catalonia, especially on the north-facing cliffs.

Don’t miss the next field visit on Saturday 25 March 2023

Save the date and come!