Supporting the survival of the Monchique oak tree in Portugal

Gathering in-depth knowledge about one of the rarest tree species of Portuguese flora in order to propagate it, expanding both its presence and diversity, is the ambition of a project aimed at preserving this precious forest from Southwest Portugal and with a clear focus on rescuing the Monchique oak tree. The challenge is difficult, but the matter is pressing, considering that this is a “critically endangered” species in Portugal.

The few remaining specimens in Portugal can be found most in the coastal mountains in the Lower Alentejo and western Algarve region. This area is the starting point of a technical-scientific work focused on saving the Monchique oak tree (Quercus canariensis) from extinction.

The opportunity to recover the Monchique oak tree falls under a broader project, “Genetic improvement, production and conservation of forest reproductive materials,” which is there to increase the resilience of the Portuguese forest to the effects of climate change. RRP – Recovery and Resilience Program supported the idea, which should be occur between the end of 2022 and 2055, under the joint coordination of the Forest and Paper Research Institute RAIZ and the National Institute of Agricultural and Veterinary Research INIAV.

The line of action “Genetic conservation and recovery of populations from endangered native species” focuses on around a dozen species, of which the Monchique oak tree is one of the most striking and challenging examples, considered “Critically Endangered” by the Red List of the Vascular Flora of Mainland Portugal due to the “continued decline in the size of the national population.”

A small and declining population means low genetic diversity, thus affecting the resilience and survival of Monchique oak tree (and the habitats where it persists) when faced with several pressures, including those amplified by climate change. It also reduces its ability to reproduce.

This challenge is even more difficult to overcome, considering that the Monchique oak tree often crosses (hybridizes) with other oak tree species better adapted ecologically, namely the Portuguese oak tree(Q. faginea), generating offsprings with morphological characteristics that make it difficult to tell them from parent species and given an even greater uncertainty when it comes to collect seeds (acorns) for the reproduction of Quercus canariensis individuals as “pure” as possible.

Aside from the small number of Monchique oak trees, the fact that they have been affected by consecutive years of drought limits the viability of acorns, impairing, from the outset, the natural in situ regeneration and maintenance of the species and its multiplication in nurseries (ex-situ).

A virtuous triangle to rescue the Monchique oak tree

To overcome such constraint work should focus on three essential angles: a virtuous triangle to move from intention to practice before it’s too late to recover the Monchique oak:

1. Characterize the species, its distribution, and genetic diversity

Identifying the Monchique oak tree specimens and characterizing the ecosystems where they were able to survive are the first steps to addressing the many challenges facing this species.

The work begins with field trips and gathering images through remote sensing (drone, LiDAR, satellite), which will be classified using innovative machine learning technologies to characterize and map the core areas where we can find this species. This work should enable us to assess the structure of these forests from the physiognomic and functional perspective and the particular environmental factors and conditions promoting their existence and permanence in the territory.

In addition, molecular characterization of selected trees will be carried out using genomic tools. The aim is thus to identify distinctive specimens of this species, analyse the level of hybridization with the Portuguese oak and characterize the diversity of the Portuguese subpopulations of this species.

This work is allocated to a team of researchers already focused on improving knowledge about the Portuguese Quercus, from BIOPOLIS-CIBIO (Research Center on Biodiversity and Genetic Resources) and the Botanical Garden of the University of Porto, the entities supporting the transfer of knowledge generated to the team in charge of the next stage of the process.

2. Reproducing and multiplying plant material

Monchique oaks trees identified for their high conservation interest will be the focus of an in-depth study on their ability to reproduce and multiply. With the involvement of a technical team with long experience in the dissemination of plant material, the best seed germination strategy (acorns) will be studied and plant dissemination tests (new shoots detaching – propagules – from the mother plant) will be carried out, as well as reproduction through in vitro tissue culture.

In the short and medium term, this information should assist the sprouting and dissemination of Monchique oak trees at the Viveiros Aliança nurseries , where this work is performed and a where a stock of mother plants should also be established to ensure continued dissemination.

Data collected helps establish protocols for the expansion (in quantity and alternatives) of breeding materials to support the growth of the population of this type of oak tree on a larger scale, which will be featured, in the future, in a catalogue adapted to the implementation of this species in the southwestern Alentejo and Algarve regions.

3. Installing grooves to increase seed diversity and availability

One of the main factors for the preservation and permanence of Monchique oak in its natural territory is the recovery of its forests. <in light of the ecological and biogeographical particular features of the Portuguese southwestern region, this type of very old forest can be preserved and populated with other high-value species (and floristic elements), many of which are considered true relics, such as the island beech (Myrica faya) and the pontic rhododendron (Rhododendron ponticum ) for example.

The aim is to recover those species that make up the natural forest habitat of this region, which includes other oak trees, such as the cork oak (Quercus suber), Kermes oak (Quercuspseudococcifera), Portuguese oak (Quercus faginea), and gall oak (Quercus lusitanica), but also species able to promote a pre-forest environment, such as the arbutus tree (Arbutus unedo), laurel (Laurus nobilis) and mock privet or green olive tree (Phyllirealatifolia).

And as these forests come into contact with riparian forests work should also focus on forest species from these environments, such as the Portuguese alder (Alnus Lusitania), the black alder (Frangula alnus subsp. baetica), and even threatened species from these environments, such as Campanula primulifolia.

Odemira and Monchique are the regions where these breeding materials will be deployed. “They will be deployed on forest properties managed by Navigator in Odemira and Monchique, both to reinforce habitats with high conservation value where the Monchique oak tree is present, as well as for future production of seed with greater genetic diversity, thus supporting other initiatives of reforestation and recovery of habitats,” informs Nuno Rico, head of Biodiversity Conservation of The Navigator Company and for carrying out this mission to restore the relic forests of the Southwest.

More resilient and well-adapted forests

The global project, which is part of this mission to recover the Monchique oak tree, replicates much of these procedures to other forest species of high economic and ecological value to improve the health, resistance, and productivity of planted forests and natural forests with greater interest for biodiversity, conservation of protected habitats and the recovery of degraded ecosystems.

Many of the species have a reduced presence in Portugal, such as the rare elf (Rhododendron ponticum), and even with proper care supporting their reproduction and expansion in nature has been difficult. Others, although more common, such as the arbutus tree (Arbutus unedo) and several native oak trees, are in great demand, in particular in projects to regenerate degraded ecosystems where there is a lack of reproductive materials for reforestation and conservation initiatives.

The effects of climate change pose new challenges to these species and their habitats, hence it is mandatory to quick-start protection and management measures, using the most advanced knowledge and tools, including spatial analysis technologies and conservation genetics. These tools are still incipient in Portugal, but they are critical to support better decision-making wherever there is the risk of extinction and habitat loss. Hence the pressing need to concentrate efforts on the conservation and creation of more resilient ecosystems better able to adapt to climate change scenarios.

These beliefs are shared by more than a dozen entities, joining forces for three years to increase the availability of better-adapted, resistant, and tolerant breeding materials and plants in Portugal to face the increased pressures of climate change.

The integrated project under the RRP Agenda Transform is called P1.1. Genetic improvement and forestry materials for reproduction, a consortium led by the Forest and Paper Research Institute RAIZ and the National Institute for Agricultural and Veterinary Research INIAV. The entities most involved in this task are the companies Navigator Forest Portugal, Viveiros Aliança, and the Center for Plant Biotechnology of Beira Interior, with consulting by BIOPOLIS-CIBIO and the Botanical Garden of the University of Porto. Also included in this project are other entities such as Altri, ESAC – The Coimbra High School of Agriculture, and ICNF – The Institute of Conservation of Nature and Forests.