WP1) Accessing “silent sites”. Sampling at lowland sites yielded sediments spanning the last 3000 to 12000 years. Although technically challenging, PalEnDNA was isolated, amplified and sequenced at all sites. To improve its recovery, a set of extraction protocols, amplification and sequencing methods was tested and implemented. Reconstruction of vegetation was also addressed by pollen analysis. Combining both proxies a dominance of coastal vegetation plants was detected, suggesting little transformation of coastal ecosystems until the arrival of Europeans. A signal of pollen and PalEnDNA from tree species was spotted, pointing to their past occurrence in the nearby mountains. Those trees are no longer present in the surrounding areas, indicating a higher transformation of forested vegetation by human activities as compared to coastal areas. Both taxonomic resolution and detection of taxa were significantly improved by PalEnDNA analysis.
WP2) Detecting “ghost taxa”. Sediments from mid-elevation sites were retrieved for detection of Lauraceae PalEnDNA. A set of specific primers to target Lauraceae DNA were designed. In general, the amount and quality of PalEnDNA sequences retrieved from mid-elevations sites was scarce, probably due to humid conditions favoring DNA degradation. Lauraceae DNA was detected at several sites but only in few samples, indicating its presence in very scattered moments in time, thus preventing further conclusions about the significance of these trees in the past. The performance of specific Lauraceae primers was good on environmental modern samples but failed when used on ancient sediment samples. Lauraceae detection was higher when using universal plant metabarcode primers. The effectiveness of other methods to recover PalEnDNA at mid-elevation sites, such as BEST 2.0 and shotgun sequencing, is being explored.
WP3) Preparing a reference sequence database. A reference database for a subset of the Canarian flora was prepared to complement the DNA barcode sequences and data from GenBank already available, with additional markers and taxa that were missing. DNA from the species that lacked information was searched in the DNA bank at the Jardín Botánico Canario Viera y Clavijo – CSIC, then amplified, and sequenced. A more complete reference database for the Canarian flora is now available to be used for barcode identification of PalEnDNA sequences.
WP4) Tracking human impact on islands. Literature available on human impact in the Canaries has been thoroughly reviewed. Data and results obtained from PalEnDNA and pollen fossil analysis are used to compare ecological variables within different scenarios of human colonization. An inter-archipelago comparison between the Canaries and New Zealand, has been the basis for an article showing how islands with contrasting natural histories result in a very similar outcome in terms of the consequences of human impact on nature.
WP5) Communicating and disseminating palaeoecological data to ensure an effective transference of the results. A workshop on the application of palaeodata into nature management and conservation was organized. Managers expressed their interest in the application of palaeoecological information and proposed media for the transference of results. The project has been introduced to the scientific community and communicated to the general public though presentations on scientific and outreach activities, news in the local press and radio, and updates via websites and social media (i.e. twitter @LCR_LTEL, @ISLANDPALECO, @FdezPalaciosLab).
