GALAPAGOS REPORT 2007-2008

Cryptogams of the Galapagos Islands (lichens, bryophytes, and fungi): New records, threats, and potential as bioindicators – a first evaluation

1 Charles Darwin Foundation 2 School of Life Sciences, Arizona State University

Introduction

Lichens, fungi, and bryophytes are frequently referred to as lower plants , non-vascular plants , or cryptogams . All terms are partially incorrect but used for convenience. Strictly speaking only bryophytes are plants. Although lack - ing conductive tissues, they are photosynthetic. Fungi are not photosynthet - ic, typically penetrating their substrate as threads of cells. Lichens are fungi in close association with algae. Their algae photosynthesize, supplying the fungus with nutrients, while the fungus provides the structural component.

A) Graphis subchryso - B) Bryopteris filicina , a C) Podaxis pistillaris , a carpa , a crustose lichen characteristic liverwort of characteristic species of dry with reddish fruiting bodies. the humid highlands. Galapagos lowlands.

Cryptogams are a diverse group (Figure 1) present in all terrestrial Galapagos ecosystems and dominant in some vegetation zones. Coastal lava is covered by thick crusted lichens that cause weathering. In the dry zone, trees are encrusted with lichens - a protective layer against overheating. In GALAPAGOS REPORT 2007-2008 the transition zone, pale green lichens tion and ecological requirements remain droop from branches, collecting mist and largely unknown. Without this informa - rainfall. Moss and liverwort carpets drape tion, understanding of terrestrial ecology trees throughout the humid zone in the is at best fragmentary. highlands, collecting the fine mist (garúa) that occurs duing the dry season and pro - Baseline inventory ducing drip pools on the forest floor. In the humid highlands, Sphagnum bogs and Lichen inventories date back to the 1960s lichen heaths are locally common. (Weber, 1966; Weber & Gradstein, 1984; Fungi are crucial for soil fertility. They Weber et al. , 1977), culminating in a pre - disintegrate organic litter or live within liminary checklist (Weber, 1986) with brief plant roots enhancing nutrient supply. updates (Elix & McCarthy, 1998; Weber, Other fungi are pathogens, and their 1993). Weber (1966) also published the potential as biocontrol agents is being first checklist of bryophytes, which has investigated for blackberry ( Rubus niveus ) been updated (Gradstein & Weber, 1982; and lantana ( Lantana camara ), two of the Weber, 1976). Reports of macrofungi date more aggressive invasive species. back to Darwin (Berkeley, 1842). Despite their importance and abun - Subsequent reports are scattered (Bonar, dance, Galapagos cryptogams have been 1939; Evans, 1916; Martin, 1948), with neglected in the past. Very few studies the most current checklist published by document which species are known, rare, Reid et al. (1981). Recent surveys have or threatened. Their potential as bioindica - significantly increased our knowledge tors has been ignored and their distribu - (Figure 2).

Figure 2. Number of species of Galapagos non-vascular plants (lichens, bryophytes, and fungi) from publications prior to 2005 and current total records (including both records prior to 2005 and from recent surveys). From December 2005 to January 2008, Norte, and Wolf. Due to their high disper - lichens and bryophytes were collected on sal capabilities, the inventory of fungi has Bartolomé, Gordon Rock, Isabela (Sierra been restricted to Santa Cruz. In total, ca. Negra, Volcán Alcedo, Volcán Darwin), 9000 specimens are now deposited at the Pinta, Pinzón, Plaza Norte, Plaza Sur, Charles Darwin Research Station. Rábida, San Cristóbal, Santa Cruz, Santa Fe, and Santiago (Figure 3). A few previ - ous collections are available from Bainbridge Rock No. 6, Daphne Major, Española, Fernandina, Floreana, Seymour

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Figure 3. Islands visited during the 2005-08 species inventory of lichens, fungi, and bryophytes. The large islands have a much wider range be interpreted with caution as Santa Cruz of vegetation zones and support higher has been more intensively studied than diversity (Figure 4); however, data must the other islands.

Figure 4. Number of non-vascular plant species (excluding non-lichenized fungi) collected in Galapagos during the 2005-08 inventory.

Most specimens are preliminarily identified ence, nine new records; Aptroot & (Figure 5). Taxonomic revisions have been Bungartz, 2007), crustose Roccellaceae published or submitted for: Collemataceae (two species new to science, twenty new (five records new to Galapagos; Bungartz, records; Aptroot & Sparrius, 2008), 2008), Ramalina (four species new to sci - Roccella (one species new to science;

| 138 GALAPAGOS REPORT 2007-2008 Tehler et al. , 2008), and Graphidaceae records; Bungartz et al. , 2008). (four species new to science, 23 new

Lichens Bryophytes Fungi

accepted preliminary accepted preliminary problematic accepted preliminary problematic problematic new

Figure 5. Number of species identifications of herbarium specimens by identification status: a) lichens, b) bryophytes, and c) fungi. Accepted = confirmed using literature and chemical and microscopic analysis. Preliminary = requiring further studies. Problematic = identification does not concur in all aspects with literature references. New = species new to science, either pub- lished, or publication in progress.

Though species are generally distributed humid zone, diversity is disproportionably throughout all habitats, lichen diversity higher. Because of anthropogenic distur - appears highest within the humid zone, bance, agricultural areas now include followed by the transition, dry, and coastal species adapted to open habitat originally zones (Figure 6). Again, these figures typical for drier zones. must be treated with caution. In the

Humid Zone (Including agricultural areas): 347 species

Coastal Zone: Agricultural Areas: 129 species 133 species

Dry Zone: 206 species Humid Zone: (with out agricultural areas): 319 species Transition Zone: 257 species

Figura 7 . Species diversity of lichens according to Galapagos vegetation zones. Note: there are spe - cies that are distributed both in the humid and agricultural zone.

A preliminary estimate suggests that dry, open habitat and less than 4% are approximately 8-10% of all lichens are believed endemic. endemic, mostly in the coastal and dry Fungi are the least studied group zone. Despite lack of historical data, the (Arturo-López, 2008) and the existing majority of species is considered native, data do not allow comparison across dif - although preliminary studies indicate ferent zones. The increase of known higher affinities for some epiphyte species species (Figure 2) can be attributed to a to introduced trees (Nugra-Salazar, 2008). recent survey of Agaricales (Arturo-López, Both diversity and abundance of 2008) and collections of phytopathogenic bryophytes is highest in the humid zone. fungi. Very few species are naturally adapted to

139 | GALAPAGOS REPORT 2007-2008 Potential as bioindicators Forest degradation from introduced herbi - vores: e.g., the destruction of vegeta - Lichens and bryophytes obtain water and tion on Santiago and Volcán Alcedo by nutrients directly from the air. They are goats. slow-growing, adapted to mature habitat with high ecological continuity, and sensi - Climatic effects: Weber & Beck (1985) tive to environmental change. Both groups observed drastic population collapses have been used in other parts of the world for some species whereas some com - as indicators of air pollution, forest health, mon bryophyte species became much and climate change (Gries, 1996; Nash & more abundant after the 1982-83 El Wirth 1988; Rose, 1976; Rose, 1992; Niño; Galapagos species should be Rose & Wolseley, 1984). adapted to these events but re-estab - Climate change has the potential to lishment has been slow. The cumula - create greater weather extremes, with tive effects of disturbance, habitat prolonged and more intense droughts and degradation, and climate change may increasing frequency of El Niño events. If have delayed recovery. these changes occur, effects should be most pronounced for the following poten - Invasive species control: herbicides (e.g., tial bioindicators: at Los Gemelos on Santa Cruz) are detrimental to cryptogam diversity 1) Coastal and Arid Zones: lichens on (Arturo-López, 2008; Nugra-Salazar, twigs and branches, in particular 2008). Ramalina spp. Restoration of native vegetation: recovery 2) Transition Zone: pendulous species is a slow process; within young forests contributing to the natural water supply epiphytes have not yet re-established; (e.g., Ramalina spp., Usnea spp., the reservoir of rare species may be Teloschistes chrysophthalmus ); some insufficient for a rapid recovery, which rare species (e.g., Lobaria dissecta ). may only occur over the long term.

3) Humid Highlands: species that rely Locally problematic areas include: on high humidity (lichens: Leptogium , Pseudocyphellaria , Coccocarpia , Trash burning at the waste deposit at Acantholichen , Dictyonema ; km 27 on Santa Cruz causes air pollu - bryophytes: Frullania , Bryopteris ). tion on a local scale; in the immediate vicinity lichens and bryophytes are no longer present, resulting in a “ cryp - Species rarity and conservation togam desert. ”

The considerable increase in known The cinder cone above Mina Granillo species results from more comprehensive Rojo on Santa Cruz is the only known surveys and improved taxonomy. Despite site for some extremely rare species. intense surveys, five historically docu - This part of the transition zone is char - mented species were not relocated and a acterized by exceptionally high diver- disproportionately high number is consid - sity ; the open quarry already con - ered extremely rare or rare (Figure 7). The tributes to dust contamination and observations are alarming. Potential caus - habitat destruction; further expansion es include: will have a detrimental impact.

Habitat fragmentation and disturbance: on inhabited islands natural forests have been considerably altered by agricul - tural land use.

| 140 Photograph: Frank Bungartz

Recommendations

A series of recommendations have resulted from this study. These include:

Complete the species inventories; expand the fungal inventory to include all vege - tation zones of Santa Cruz.

Monitor recovery following goat eradication on Santiago, Volcán Alcedo, and Pinta; identify species that recover rapidly vs. ones that recover slowly.

Monitor long-term effects from climate change and El Niño events, with particular emphasis on disturbed sites.

Investigate the effects of eradication and control regimes for invasive plant species on the cryptogam vegetation.

Monitor population recovery during restoration of native vegetation.

Abolish or minimize trash burning.

Reduce and restrict mining to areas of low species diversity (e.g., alternative sites like the Mina Granillo Negro).

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