Last Saturday, June 1st, we went on a field trip with the volunteers to the transects N2 and N3, in Roses. The objective was to explain how to take the data and upload it in iNaturalist, how to fill out the population monitoring form for the new volunteers, and also see what species appeared along the route. The itinerary began at the Roses lighthouse, at the beginning of transect N2 heading east and continued until the end of transect N3, ending at Canyelles Petites beach.
The first thing we located was a large population of Ailanthus altissima (tree of heaven or Chinese sumac) with many regrowth and juvenile individuals. We took the opportunity to talk about the problem that this invasive plant represents in Mediterranean habitats, and how the technicians from the Girona Provincial Council are experimenting with parasitic fungi of the genus Verticillum to prevent the spread of this plant.
We also saw Opuntia stricta and O. ficus-indica (prickly pear) affected by mealybugs. We stopped to explain the biological control that is being carried out in Cap de Creus with this wild carmine mealybug (Dactylopius opuntiae) (see more about the featured plant) and the effectiveness that this treatment is showing.
Unexpectedly, we also detected an individual of Nicotiana tabacum, the tobacco plant, with this finding being the first observation in the Costa Brava.
Volunteers observing the Nicotiana tabacum and the discovered tobacco plant.
The trip almost reached transect N4, and along the route we found Agave Americana (maguey or century plant), Aloe maculata (soap or zebra aloe), Aloe ciliaris, Arundo donax (giant reed), Carpobrotus edulis (hottentot-/sour-fig or ice plant), Datura stramonium (jimsonweed or thornapple), Dimorphoteca ecklonis (African daisy) and Senecio angulatus (Cape ivy) among others.
We found many Kalanchoe × houghtonii (mother of thousands) clearly expanding and with numerous specimens between the rock crevices, occupying the habitat and displacing various native Sedum species.
We also observed many specimens of Agave americana affected by the black weevil (Scyphophorus acupunctatus), which is being monitored by the University of Barcelona by the researcher Juli Pujade https://ichn.iec.cat/wp -content/uploads/2023/06/13_2023_Pujade__Barea.pdf.
This beetle, detected for the first time in the province of Barcelona in 2007, parasitizes and eventually kills the Agave plants. But, it also parasitizes other invasive plant species in our area such as aloes (Aloe arborescens) or yuccas (Yucca aloifolia) https://www.samarucdigital.com/article/el-morrut-negre-una-nova-amenaca. We saw a possibly affected specimen, of this last species, during the route and took samples for analysis.
Once the activity was over, and as is customary, a “bonding pica-pica” was held. It was reminded that during the summer there will be a pause of field trips in the schedule until September.
Group photo
