Serra da Arrábida: Mushroom Paradise

Why Arrábida is unique

Serra da Arrábida is a mountain range on the southern edge of the Setúbal Peninsula, running east to west parallel to the coast. Its highest point reaches about 500 metres. The natural park covers 17,000 ha.

But it’s not about size. Arrábida is a limestone island in a country of acidic soils.

Almost all of Portugal sits on granite, gneiss and schist — rocks that produce acidic soils (pH 4.5–6.5). Arrábida is the exception: here, Jurassic dolomite limestones create alkaline soils with pH 7.0–8.5. For fungi, this is crucial: many species, including the black truffle (Tuber melanosporum), grow only on limestone.

This makes Arrábida potentially the only natural habitat for black truffle in Portugal.

Vegetation — a “Mediterranean relic”

Arrábida is one of the rarest examples of Mediterranean maquis in Portugal and a recognised international scientific relic. Such vegetation once covered much of southern Europe but has almost disappeared.

Some ~1,450 plant species have been described here — that’s 40% of all Portugal’s flora in a tiny area. Over 70 species are rare or endemic.

Key trees and shrubs (mycorrhizal hosts)

Two slopes — two worlds

A 2002 study (Microbial Ecology) confirmed that the north and south slopes of Arrábida are two different fungal worlds:

• North slope (humid) — richer diversity, more moisture-loving species
• South slope (dry, facing the sea) — more specialised community, xerophilic species

Researchers collected 1,029 strains of filamentous fungi (at least 36 species) and 540 yeast strains (at least 46 species) from the leaves of just five plant species. Some taxa proved to be previously undescribed species.

Mushrooms of Arrábida

Core mycorrhizal community of limestone oak forests

Studies of Mediterranean oak forests (relevant to Arrábida) reveal:

In an old-growth Quercus ilex forest (a close relative of Q. coccifera), 234 species were recorded from 5,382 fruiting bodies: 166 ectomycorrhizal and 68 saprotrophic.

Across the Iberian Peninsula, 605 mycorrhizal taxa have been documented in Mediterranean oak forests.

Black truffle potential

More on truffles: Black truffle

Rare find: Amanita torrendii

In the Metropolitan Biodiversity Park in Seixal (Setúbal district), Amanita torrendii became the thousandth identified species. This is a typically Mediterranean fungus found exclusively in Mediterranean and sub-Mediterranean forests on sandy soils, associated with Quercus suber.

• IUCN status: Near Threatened
• Global records: ~210 GBIF records, of which ~33 from Portugal
• Range: Spain, Portugal, France, Italy, Greece, Cyprus, Morocco, Algeria, Turkey

Edible species expected in Arrábida

Dangerous species

Seasonality

Key factor: maritime influence (morning fog, ocean humidity) can offset autumn dryness, extending the mushroom season compared to inland Alentejo.

Contrast with surroundings

Arrábida’s uniqueness is especially striking when compared with neighbouring ecosystems:

Within just a few kilometres — three entirely different mushroom worlds.

Read more: Pine forests of Tróia, Sado Estuary

Practical tips

1. Natural park — foraging may be restricted. Check regulations with ICNF or the park administration
2. Best season: October–November (after the first autumn rains)
3. North slope — richer in fungi, more humid
4. Look under Quercus faginea and Q. coccifera — the main mycorrhizal hosts
5. Maquis — dense and hard to navigate. Stick to trails and open areas

Mycological activities nearby

• EcoFungos (Seixal) — mycological association, founded 2004. Runs walks and tastings at Parque Metropolitano da Biodiversidade. Contact: ecofungosam@gmail.com
• CM Sesimbra — the municipality organises mushroom foraging courses (CIPA, Quinta do Conde) and walks at Lagoa Pequena
• Arrábida Walking Festival (March) — 40+ activities including botanical and gastronomic walks

See also

• Arrabida Natural Park — geography, fauna, marine park and conservation status of the protected area (Setubal Encyclopedia)

Sources

1. Inácio J. et al. — Estimation of phylloplane fungal diversity on selected plants in Serra da Arrábida // Microbial Ecology, 2002
2. Duarte S. et al. — Filamentous fungal diversity in a Mediterranean ecosystem // Fungal Diversity, 2011
3. Rinaldi A.C. et al. — Ectomycorrhizal fungal diversity — the state of the art // Plant Biosystems, 2008
4. de Vries B.W.L. et al. — Macrofungi of old-growth Quercus ilex forest // Cryptogamie Mycologie, 2003
5. Parque Natural da Arrábida — Plano de Ordenamento, ICNF
6. CM Seixal — Mil espécies já identificadas no Parque da Biodiversidade, 2024
7. BioDiversity4All — Checklist de Parque Natural da Arrábida