New data on lichen flora of the Edough Peninsula in north-eastern Algeria

Chaker A., Fekroune K., Hassaine A., Slimani A., Zerari L., Moulaï R., 2023: New data on lichen flora of the Edough Peninsula in north-eastern Algeria. – Botanica, 29(1)


INTRODUCTION
The extreme northeast of Algeria and the northwest of Tunisia are considered the Mediterranean regional hotspots due to their high biological diversity (Véla & Benhouhou, 2007), comprising many vital areas for plants richness (Radford et al., 2011), such as the Edough Peninsula. Eastern Numidia belongs to two bioclimatic areas: the subhumid and the humid, resulting in high atmospheric humidity that allows the development of a rich flora within a variety of ecosystems, including the oak tree forest, which has a special place among the Mediterranean forests (Bennadja et al., 2013). In addition to the undeniable economic role played by the cork oak forests, they play an essential ecological role, contributing to the maintenance of rich biodiversity (Bennadja et al., 2013). Furthermore, some lichen species that have never been observed in Algeria have recently been recorded on this type of substrate in the study region. Such species include Usnea cornuta Körb. (Fekroune-Chaker, 2016), Nephroma parile (Ach.) Ach., and Parmelioropsis afrorevoluta (Krog & Swinscow) Elix & Hale (Ali Ahmed et al., 2018). Chaker et al. (2021) have reported that, according to the Ministry of Land Management and Environment (MATE, 2014), Algerian lichen diversity has received little scientific attention from 1854 (Nylander, 1854) to 1955 (Werner, 1955). Then, however, the Second World War and the Algerian War of Independence interrupted this work. Subsequently, some fragmentary regional inventories have been performed (Semadi et al., 1997;Rebbas et al., 2011;Serradj et al., 2013, Khedim, 2014Boutabia et al., 2015;Ali Ahmed et al., 2018;Merabti et al., 2018;Chaker et al., 2021;etc.), including updates of the earlier inventories (Aït Hammou et al., 2014).
This study aimed to update the current data on the diversity of lichen flora of the Edough Peninsula in north-eastern Algeria.

MATERIALS AND METHODS
The Edough Peninsula is a small coastal massif that borders Annaba (Bône) from the west-southwest to the north (Fig. 1). Its highest point, Kef Sabaa, reaches 1.008 m above sea level. The peninsula protrudes from the coastline between the Cap de Garde to the east, which closes the bay of Annaba, and the Cap de Fer to the west of the massif (Boulemtafes, 2015), which delimits the Gulf of Skikda (Philippeville). The Edough Peninsula is in the region of Annaba, which belongs to the Mediterranean bioclimate region characterised by temperate, humid winters and hot, dry summers. According to Hamel et al. (2013), the average annual rainfall in the Edough Peninsula is 1115.5 mm, with an average maximum temperature of 28.9 C° in the hottest month and an average minimum temperature of 4.6 C° in the coldest month.
The surveyed locality is situated on the northern slope of the Edough (36.920198° N, 7.697600° E) at an altitude of 742 m above sea level. This station comprises a 3419 ha forest of Quercus suber. The lichens were primarily found on the rhytidome of Quercus suber. The lichen surveys were conducted on forty-two cork oak trees. These surveys systematically covered all four sides of the trunk from 0.50 m to 2.0 m above the soil level to avoid the basal protection provided by the grass cover and the eutrophication caused by animal faeces (Oran & Öztürk, 2012;Boutabia, 2016). Specimens with a well-developed thallus bearing typical, clear, and unaltered fruiting bodies were chosen, which facilitated the identification of species. A sample of each species was taken with a knife by gently removing a piece of bark to verify species that could not be identified in situ. These samples were then analysed in the laboratory.

RESULTS AND DISCUSSION
The analysis of lichen samples from the Edough Peninsula on the rhytidome of Quercus suber, revealed the presence of 45 lichen taxa (Table 1). Nineteen taxa were newly discovered in the study area. However, they have neither been mentioned by Ali Ahmed et al. (2018) in their work on the lichen diversity of the Edough Peninsula nor by Fekroune-Chaker (2016) in their report on species to be protected in the Fig. 1. Map of the location of the study area. The Edough massif is in green (OSM, 2022) Edough Peninsula. Among these nineteen species, we identified two taxa (Pectenia plumbea morphotype plumbea and Fuscopannaria leucosticta) that are quite rare in their distribution area, found on only three proximal phorophytes in an area of 120 m 2 . According to the Management Plan of Degelia plumbea in Canada, this endangered species occurs only in Canada, the United States, the British Isles, Scandinavia and the Iberian Peninsula (Environnement et Changement Climatique Canada, 2022). However, Otálora et al. (2017) have concluded that the biogeographic analysis of Pectenia plumbea indicates that the Mediterranean basin is the most likely ancestral distribution area of this species. Pectenia plumbea occurs in Western Europe, according to COSEPAC (2010), but in Algeria, it has been reported in previous studies (Flagey, 1896;Harmand, 1909or Werner, 1949 as well as more recently (Djellil, 1989;Boutabia, 2016;Hamralaine et al., 2019), but never in the current study area (Edough Peninsula).
Fuscopannaria leucosticta has previously been considered non-existent in Algeria (Otálora et al., 2017). However, according to Amrani et al. (2018), this species has been reported in earlier studies on Algerian lichen flora, including Flagey (1891Flagey ( , 1896, Harmand (1909) and Werner (1949). Since then, it has neither been mentioned in the Update of the inventory of lichens in Algeria (Aït Hammou et al., 2014) nor the Lichenological exploration of Algeria (parts I and II) by Amrani et al. (2015Amrani et al. ( , 2018. Therefore, besides being considered new to the region, it represents a national rediscovery. This species has also reappeared in Japan (Jørgensen, 2000).
As stated in Jørgensen's (1999) identification key for the diagnostic character of the family Pannariaceae, with apothecia and without a thalline margin, the genus Degelia (now Pectennia) was characterised by a placodioid thallus. Accordingly, its margin has a distinctly lobed aspect (Fig. 3, A-C), and apothecia often "coronate", surrounded by a separate thalline rim (Fig. 3, B).
Regarding the thallus's upper surface, we can observe small wrinkles (Fig. 3, C) and longitudinal whitish striations arranged in a distinct network, as Cannon et al. have reported (2021). Moreover, the margin of the thallus is formed by broadly rounded lobes with thick margins and upright tips (Fig. 3, A, C). The absence of isidia and soredia (Fig. 3, A-C) confirms the plumbea morphotype, as noted in the scientific literature (LM, 2022;AFL, 2022;COSEPAC, 2010). This proves the plumbea morphotype as it is distinguished from the isidia morphotype by the absence of isidia and the presence of warts (as explained by Roux et al., 2017), which are large and thick globular lobes ( Fig. 2; Fig. 3, B), formed primarily in the central part of the thallus.
It was observed that the upper face of the thallus of P. plumbea is light grey (Fig. 2), and the lower face is covered with a strong, thick whitish tomentum (Fig. 3, A). Its apothecia are lecidein (called biatorine) and are usually numerous (Fig. 3, B). LM (2022), AFL (2022) and COSEPAC (2010), report that apothecia have a planar disc rarely convex except in rainy weather, reddish-brown to orange-brown, with no thallin margins but with lighter, non-persistent hyaline margins and pale. These morphological characteristics were noted for our samples ( Fig. 2;  Fig. 3

, B).
No significant chemical colour reactions were observed. The photosymbiont is a cyanobacterium: Nostoc, so the thallus takes on a dark grey-blue col- National Park of El Kala (El Tarf)
On trunk Semadi (1989), Djellil (1989)  our in the presence of water (Fig. 3 A, B and C compared to thalli in the dry state in Fig. 2 and Fig. 4). Jørgensen (2000Jørgensen ( , 2007 has made the same observation. Species in Fig. 4 are present up to the mountain zone (above 700 m in altitude), on the cracked bark of Quercus suber, together with mosses ( Fig. 4) in our study area (Edough Peninsula). Pectenia plumbea was observed at the same locality (Edough) on three trees of Q. suber. Most of the thalli were mature and had numerous apothecia (Fig. 3, B; Fig. 4). Furthermore, Pectennia plumbea is a component of the Lobarion pulmonariae Hilitzer1925 (Gilbert, 2000;Roux, 2013;Coste, 2011b), a lichen alliance of the Quercus suber forests of the Edough Peninsula, which is used in this region for the biomonitoring of air pollution due in particular to acid precipitation. Lobarion pulmonariae is most often found on mosses on trunks of generally old deciduous trees, in very humid sites where microclimatic conditions are relatively stable (Roux & Coste, 2005;Coste, 2011b), which is the case in the Quercus suber forests of our study area.

Fuscopannaria leucosticta (Tuck.) P. M. Jørg.
Fuscopannaria leucosticta is the second species of the family Pannariaceae studied in this research. It was found on the rough bark of cork oak (Fig. 5, A and B). This lichen is known to be very aerohydrophilic, as has been reported by Roux et al. (2017). Its thallus consists of many small overlap- ping lobes (like shingles) (Fig. 5, B and Fig. 6, B), usually forming irregularly shaped colonies of a few centimetres in diameter (Fig. 5, A). We also observed apothecia with a distinct thalline margin (Fig. 5, B and Fig. 6, A), as described by Jørgensen (1999). The disc of apothecia is less than 1 mm in size (Fig. 6,  A), and it extends above the surface of the cortex and is surrounded by a margin of the same colour as the thallus (Fig. 6, A and B), consisting of both the fungus and the cyanobacterium.
The thallus's upper surface (cortex) is often olive grey (Figs 5 and 6), as it has been reported by COSEPAC (2019). At the same time, the upper surface of their small squamules (less than 0.5 mm in diameter) has lobes of a visible white border formed by the tomentum (Fig. 6, A and B). Fuscopannaria leucosticta has a black prothallus (Fig. 6, B) consisting of a blue-black fibrous mat of hyphae that underlies the thallus and extends beyond its edges (Fig. 5, B).
Asexual reproductive structures, such as soredia, were absent, a typical characteristic of the species, as has been reported by COSEPAC (2019).
Pectenia plumbea and Fuscopannaria leucosticta prefer isolated old oaks over one metre in diameter in open forests with a clear undergrowth, as observed at the sites where these two lichens of the Pannariacea family were found. Haughian et al. (2019) have pointed out that these species are a valuable indicator of undisturbed old-growth forests.