Chorology of Juniperus Thurifera (Cupressaceae) in Morocco
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2005, vol. 54, 41–50 Angel Romo, Adam Boratyński Chorology of Juniperus thurifera (Cupressaceae) in Morocco Received: 6 April 2005, Accepted: 2 June 2005 Abstract: The geographic distribution and occurrence conditions of Juniperus thurifera subsp. africana in Mo- rocco were studied. The literature and herbaria data, together with field observations formed the basis of de- tailed maps of distribution of the species in the Middle and High Atlas and allow us to analyze its vertical dis- tribution. The taxon occurs in the sub-arid and arid zones of the Middle and High Atlas with a separate popu- lation in the Anti-Atlas, mostly between altitudes 2000 and 2700 m, with an altitudinal maximum at 3400 m and a minimum at 1700 m. It forms forests in the area of about 30 000 ha. In many places of the High Atlas it is the only wood source for local populations. It is strongly endangered because of over exploitation of the wood, over pasturing and lack of seedlings and young specimens. Additional key words: plant geography; plant ecology, High Atlas, Middle Atlas, Anti Atlas Adresses: A. Romo, Consejo Superior de Investigaciones Científicas-AB, Institut Botànic de Barcelona, Passeig del Migdia s/n. Parc de Montjuïc, 08038 Barcelona, Spain; e-mail: [email protected] A. Boratyński, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, 62-035 Kórnik, Poland, e-mail: [email protected] Introduction very schematically (Gauquelin et al. 1999). It occurs mostly in two centers in Morocco and also grows in The tree-like Juniperus thurifera L. is a typical com- the Aurès mountains in the Atlas of Algeria (Quézel ponent of vegetal landscapes of the semi-arid moun- and Santa 1962; Quézel 1980). tain regions within the western part of the Mediterra- Much of the data concerning the distribution of nean region. It is a variable species, in part as a result Juniperus thurifera and conditions of its occurrence in of long-term isolation of populations dispersed in Morocco is dispersed through several floristic and separate mountain massifs. In Africa it is known as phytosociologic publications (Maire 1926; Humbert subspecies africana (Maire) Huguet de Villar (Gau- 1928; Jahandiez and Maire 1931; Emberger 1938, quelin et al. 1988; Romo and Boratyński 2005), since 1939; Emberger and Maire 1941; Quézel 1957; from the nomenclatural viewpoint all the references Lecompte 1969; Quézel and Barbero 1981; Gauquelin of J. thurifera from Morocco should be referred to 1988; Fromard and Gauquelin 1993; Benabid and subsp. africana. Fennane 1994; Auclair 1996; Alifriqui 1986; El The general map of geographic distribution of Alaoui and Boumezzough 1993; El Alaloui et al. Juniperus thurifera in Africa (including subsp. africana) 1994, 1999; Blali 2001; Thinon and Alifriqui 2001; has been published several times (see Tralau 1969), Gauquelin et al. 2002; Rahou 2002; Quezel and but without detailed data (Fig. 1). The area of distri- Medail 2003). The synthetic Moroccan floras tradi- bution of the subspecies africana was recently shown tionally give information about the occurrence of the 42 Angel Romo, Adam Boratyński Fig. 1. General range of Juniperus thurifera in the Mediterranean region species in the Middle and High Atlas (see for example ducted in 1985–2004 by A. Romo provide an impor- El Oualidi and Mathez 1999). tant supplement to the collected material and were Juniperus thurifera is a forest-forming tree, but in included in the database. Morocco it regenerates only sparsely and as a rule The results of distribution are analysed carto- only old trees are observed in most localities (Fen- graphically for the Middle and High Atlas separately, nane and Ibn Tattou 1998; Gauquelin et al. 1999). and as general for Morocco. The vertical distribution The utilization of the wood, pasture activity and over- is demonstrated on the profiles of the main water- grazing are recognized reasons for this present state sheds of the Middle and High Atlas separately. The (Quézel 1980; Quézel and Pesson 1980; Auclair connections of the species localities with particular 1996; Montés et al. 2000, 2002). forms of relief, exposition and inclination were The suggested protection of Juniperus thurifera shown graphically (Boratyński 1985) for various subsp. africana (Fennane and Ibn Tattou 1998) needs altitudinal layers of the mountains. to be based on a sufficiently accurate recognition of its distribution and conditions of occurrence. So, the Results main aim of the paper is a critical compilation of the data on the species’ geographic repartition and its Distribution main ecologic conditions of occurrence in Morocco, dispersed through several dozen publications and in The occurrence of Juniperus thurifera in Morocco is herbaria. With these data as a solid background, the connected with the high mountain ridges. It grows in authors’ field investigations will also be used to illus- the Middle Atlas, the High Atlas and is known from trate the present state of J. thurifera in the African part dispersed localities in the Anti Atlas. of its range. Juniperus thurifera grows most frequently in the Middle Atlas. It forms loose forests above the vegeta- Methods tion zone of forests of Cedrus atlantica and/or Quercus ilex, even covering extended areas, especially in the The geography was studied on the basis of data dis- central part of the Middle Atlas (Fig. 2). Neverthe- persed in botanical literature concerning Morocco, less, the distribution of J. thurifera is not on a continu- and in herbaria [B, BC, G, KOR, MA, MPU, P, RGN ous scale and is divided into several dozen more or (Acronyms of herbaria follow Holmgren et al. 1990)] less isolated populations, which cover the mountain where the main collections of Moroccan plants are massifs of sufficiently high elevations. The forest preserved. All the data were put into one database, communities formed or dominated by J. thurifera are which included possibly precise position (locality), developed on the elevated parts of particular moun- and also: 1) altitude, 2) description of relief, 3) expo- tain massifs of the Middle Atlas, mostly at altitudes sition, 4) plant community and 5) the status of the between 1900 and 2100 m (Fig. 3). Below 1900 m the species, the number of individuals, dimensions, evi- species occurs as dispersed specimens, with an dence of regeneration, and threats when available altitudinal minimum of about 1800 m at Aïn Nokra. from the source data. The field observations con- The most elevated localities it attains are at 2600 m Chorology of Juniperus thurifera (Cupressaceae) in Morocco 43 Fig. 2. Detailed cartography of Juniperus thurifera populations in the Middle Atlas (after Lecompte 1969, supplemented with herbaria and bibliographic records and authors’ field observations) on the southern slopes of Bou Iblane and 3000 m at a minimum of about 1500 m in the vicinity of Ilmil, Bou Naceur. and a maximum at 2700 on the slopes of Jbel Toubkal The distribution of Juniperus thurifera in the High and Jbel Ayachi and even 3150m on the Jbel Imidghas Atlas is more dispersed than in the Middle Atlas (Fig. (Fig. 5). It is strongly restricted by the local popula- 4). As in the previous region, the species forms a for- tion, as it is the only wood resource in some regions. est belt in the mountains, mostly above the vegeta- The present localities of the species conserve predom- tion zone of Quercus ilex and Juniperus phoenicea, but inantly tree-like individuals, completely without communities of J. thurifera do not cover such exten- young individuals and seedlings. sive area. The occurrence of J. thurifera is connected In the Anti Atlas only a few localities of Juniperus mostly with altitudes between 1850and 2500m,with thurifera are known (Fig. 4). The species occurs only Fig. 3. Altitudinal distribution of Juniperus thurifera in the Middle Atlas 44 Angel Romo, Adam Boratyński Fig. 4. Detailed cartography of the Juniperus thurifera populations in the High Atlas (on the basis of herbaria and bibliographic records and authors’ field observations) Fig. 5. Altitudinal distribution of Juniperus thurifera in the High Atlas. as single individuals, dispersed at altitudes of about such as sandstones and schist rocks, with a low con- 2550–2700 m on Jbel Sarhro and between 2700 and tent of Ca. 3200 m in the massif of Jbel Siroua (Fig. 5). The soil where J. thurifera grows is predominantly only fragmentarily developed. The species grows very Occurrence conditions frequently on stony gravels or in the fissures of rocks The present occurrence of Juniperus thurifera is con- filled with clay, but without a humus horizon. The nected with slopes and concave relief forms, mostly more typically developed soils where the humus hori- exposed to the South, East and North. The species zon can be easily recognized, have been observed in has not been reported from localities exposed toward the areas of the Middle Atlas, especially in places with the Atlantic. It seems to avoid the north-westerly and a richer herbal vegetation. In the High Atlas such site westerly exposed localities (Fig. 6). conditions are met with only scarcely, as for example Most of the J. thurifera stands were reported from in the Oukaimeden. calcareous rocks, but it grows also on other substrata, Chorology of Juniperus thurifera (Cupressaceae) in Morocco 45 N N 50 50 High Atlas, High Atlas frequency of localities cover NW NE NW NE [N=96] [N=44] 25 25 W 0 E W 0 E 2501 and more SW SE 2101–2500 SW SE to 2100 total S S N N 50 50 Middle Atlas Middle Atlas NW NE frequency of localities NW NE cover [N=31] [N=12] 25 25 W 0 E W 0 E 2101 and more SW SE SW SE to 2100 total S S Fig.