1 Introduction: Climate, Substrates, Flora and Biogeography

The Southeast of the Iberian Peninsula presents large tracts of arid land (Alcaraz and Delgado 1998) with many species and plant communities with the closest relationships to the North African ones in the whole of Western Europe (Alcaraz et al. 1991). This area seems to have been under arid conditions for a long time, allowing the evolution and persistence of hundreds of plants species adapted to those environments, some of them endemics, and others shared with the semiarid Magreb (Algeria and Morocco) and the northern Sahara desert Alcaraz et al. (1989, 1991). So, despite its relatively small size, this area merits the biogeographical rank of province (Murcia-Almería province) (Alcaraz et al. 1991).

The area lies in SE Spain between 36.67° – 38.66° N and 0.1° E – 3.04° W (Fig. 5.2), covers 12,361 km2 and spans altitudinal ranges from 0 to 1387 m. It embraces the lands near the Mediterranean Sea between the southern slopes of the Dianic ranges, in the area surrounding Benidorm, and the Baetic massifs of the Sierra de Gádor and the Alpujarras, including the southern areas of the provinces of Alicante, Albacete, Murcia and Almería. The altitudinal range of this fringe is variable, reaching its lowest level in the Segura valley. Murcia-Almería is a low-relief biogeographical province, with just two mountains (the Sierras de Carrascoy and Alhamilla) reaching 1000 m in height; the rest of the mountains in the province are geographically continuous introgressions of the Baetic ranges and cannot be considered as Murcia-Almería from a biogeographical point of view (Peinado et al. 1992).

Fig. 5.1
figure 1

The alternation of marl, on the slopes, and saline soils, in “ramblas”, form one of the most impressive landscapes of the arid Southeast (rambla de Tabernas, Almería)

Full size image
Fig. 5.2
figure 2

Map of the arid Southeast (Murcia-Almería province). 1. Alicante-Murcia sector: 1a Alicante subsector, 1b South Murcia subsector, 1c North Murcia subsector. 2. Almería sector: 2a East Almería subsector, 2b Cabo de Gata subsector, 2c West Almería subsector

Full size image

The macrobioclimate of the area is Mediterranean (Rivas-Martínez et al. 1999); the bioclimate is xeric oceanic and, locally, desertic oceanic. Inframediterranean, thermomediterranean and, restricted to the interior and a few mountain summits, mesomediterranean, are the thermotypes represented. It is remarkable that the areas under inframediterranean thermotype are the only ones in the Peninsula (Alcaraz and Delgado 1998). The annual rainfall ranges from 180 to 400 mm and is very seasonal, showing a clear summer minimum (Alcaraz and Delgado 1998). This climatic aridity is a result of its sheltered position in the southeastern extreme of the Peninsula, which positions this region in a severe rain shadow with respect to the most important precipitation sources from the Atlantic and the northern Mediterranean sea (Rivas-Martínez et al. 1999) (Fig. 5.1). Accordingly, arid (this ombrotype is not present in any other area of the European continent), semiarid and dry, the latter restricted to a few mountains summits (the Sierras of Carrascoy, Almenara, Cabrera and Alhamilla), are the ombrotypes represented.

The geology is complex and there are many different rock types (gypsum, limestone, marl, phyllite, quartzite, schists, slate, volcanic rock, etc.). The area’s climate favors soils with a high CaCO3 content, except when they are developed from rocks of a very acid nature, as in the Cabo de Gata mountains. Of particular interest are some isolated hills, called “cabezos”, between Águilas and Mazarrón, in the Cartagena plain and forming islands in Mar Menor, that are volcanic post-orogenic uplifts of Neogenous origin.

The flora of this province is essentially Mediterranean (46.9% of the taxa), but is very special, with a high percentage of taxa that are endemic to this province (4.18%) and a high proportion of taxa that are Iberian endemics (9.63%); furthermore, this province contains an interesting component of taxa with an Iberian-North African distribution pattern (4.88%). Contrasting these figures that indicate endemicity, mediterraneity and relationships with North Africa, are the 1.59% Mediterranean-Atlantic species (Alcaraz 1984).

The Murcia-Almería province has one of the highest floristic diversities of all Spanish areas (Alcaraz et al. 1991) and includes three endemic genera (Euzomodendron, Guiraoa and Lycocarpus). Much of the endemic diversity of the Murcia-Almería province is concentrated in a few genera which may still be actively evolving (Helianthemum, Limonium, Sideritis, Teucrium and Thymus); other endemics are undoubtedly of desertic or steppic origin (Saharo-Arabian or Irano-Turanian), but they have evolved in isolation, due to area disjunction; this seems to be the case of Anabasis hispanica, Haloxylon salicornicum, Suaeda pruinosa and several Salsola species.

The restriction of plants to certain soil types is an important feature of the Murcia-Almería flora. Gypsaceous soils are an important hotspot of reduced-area endemics such as Chaenorhinum grandiflorum, Coris hispanica, Helianthemum alypoides, Herniaria fruticosa subsp. erecta, Santolina viscosa, Teucrium balthazaris, Teucrium lepicephalum and Teucrium turredanum. Marls also support endemics in Murcia-Almería province, with Achillea santolinoides subsp. santolinoides, Astragalus hispanicus, Euzomodendron bourgeanum, Genista ramosissima, Genista valentina subsp. jimenezii, Haloxylon salicornicum, Herniaria fontanesii subsp. almeriana, Moricandia foetida, Salsola genistoides, etc. Rocky places, mostly formed by limestones and dolomite, are also rich in exclusive plants as Antirrhinum hispanicum subsp. mollisimum, Centaurea saxicola, Galium ephedroides, Genista murcica, Lafuentea rotundifolia, Satureja obovata subsp. canescens, Sideritis glauca, Teucrium rivasii, Teucrium freynii and Teucrium intricatum.

A particularly interesting edaphically delimited region is the volcanic area of the Cabo de Gata; several taxa are endemic in this area and they are restricted to acid volcanic rocks: Antirrhinum charidemi, Dianthus charidemi, Sideritis osteoxylla, Ulex canescens and Verbascum charidemi.

On coastal sand dunes the recently described Asparagus macrorhizus, Helianthemum marminorense and Ononis talaverae are exclusive of the Murcia-Almería province.

On saline and subsaline soils there are several endemics, such as Anabasis hispanica, Frankenia corymbosa, Helianthemum motae, Salsola papillosa and the remarkable genus Limonium (Limonium album, Limonium caesium, Limonium carthaginense, Limonium cossonianum, Limonium delicatulum, Limonium estevei, Limonium furfuraceum, Limonium insigne, Limonium parvibracteatum, Limonium santapolense, Limonium supinum and Limonium tabernense).

Biogeographically, two sectors have been distinguished in the Murcia-Almería province: Alicante-Murcia (Fig. 5.2, 1a–1c) and Almería (Fig. 5.2, 2a–2c). The Alicante-Murcia sector shows influences of The Mancha and coastal Levantine areas, while the Almería sector has influences from the Baetic ones (Alcaraz et al. 1991).

The Alicante-Murcia sector comprises the northern areas of the Murcia-Almería province; it includes the territories of the basins of the Segura and Vinalopó rivers and an important part of the Campo de Cartagena, as well as the coastal areas of the Mar Menor, reaching in the north the region of Polop-La Nucia-Altea in the southern part of the Dianic ranges. Some summits above 1000 m, such as the Carrascoy range (Murcia), have Manchegan vegetation. Minor differences can be used to characterize the three subsectors existing within it: Alicante (1a), South Murcia (1b) and North Murcia (1c) (Fig. 5.2) (Alcaraz et al. 1991).

The Almería sector, which includes the coastal and sublitoral regions between the Cabo de Palos (Murcia) and Adra (Almería), also includes more inland areas in the basin of the Guadalentín (Lorca, La Paca), Almanzora (Olula del Río) and Andarax (Abla, Canjáyar) valleys. It comprises some plains (Fuente Álamo, Lorca, Puerto Lumbreras, Níjar), including also some modest ranges (Almenara, Cabrera and Alhamilla). Minor variations led to recognize three subsectors: East Almería (2a), Cabo de Gata (2b) and West Almería (2c) (Fig. 5.2) (Alcaraz et al. 1991).

2 Forest, Woodlands and Mantel Vegetation

Because of the arid conditions, the potential natural vegetation of the Murcia-Almería province (Tables 5.1 and 5.2), is not true forest, but shrublands with more or less scattered trees, belonging to the Pistacio lentisci-Rhamnetalia alaterni order, mostly to the alliances Periplocion angustifoliae and Asparago albi-Rhamnion oleoidis, and Cytiso villosi-Telinetalia monspessulanae, alliance Genisto spartioidis-Phlomidion almeriensis, the latter being endemic to the province, and, in the mesomediterranean belt, to the Rhamno lycioidis-Quercion cocciferae. The only exception to this trend occurs on some north-exposed slopes and on some mountains summits, where the dry ombroclimate is present; there the potential natural vegetation is holm-oak forest of the Quercetalia ilicis order.

Table 5.1 Natural potential associations (sclerophyllous) in the Murcia-Almería province
Full size table
Table 5.2 Natural potential associations (brooms) in the Murcia-Almería province
Full size table

The Periplocion angustifoliae alliance (Table 5.1, rows 1–4) includes communities dominated by Periploca laevigata subsp. angustifolia (cornical), Gymnosporia senegalensis (arto), Ziziphus lotus (azofaifo), and some open woodlands of Tetraclinis articulata. The Periploca laevigata subsp. angustifolia brushwoods are the potential natural vegetation of the inframediterranean arid belt, the only localities with a desertic oceanic bioclimate in continental Europe (Table 5.1, row 1). Thorny brushwoods of Ziziphus lotus (Table 5.1, rows 2–3) are the potential natural vegetation in closed basins (Fuente Álamo, Lorca-Puerto Lumbreras, Níjar, etc.) (Ziziphetum loti), and in the western part of the West Almería subsector on plains leading to the coast (Gymnosporio-Ziziphetum loti). Ziziphus lotus shrublands create landscapes that are very similar to those of the Saharan wadis. The Arisaro simorrhini-Tetraclinidetum articulatae is a relict vegetation related to the north African woodlands of this species; it forms an open forest growing on the east-facing, sunny rocky slopes of the Sierra de Cartagena (East Almería subsector) (Table 5.1, row 4; Fig. 5.3).

Fig. 5.3
figure 3

The Arisaro simorrhini-Tetraclinidetum articulatae is an open forest. Here (Peña del Águila, Murcia) this remarkable tree Tetraclinis articulata grows naturally at its only location on the European continent

Full size image

Apart from the above mentioned brushwoods and woodlands, the main type of potential natural vegetation in the thermomediterranean semiarid bioclimatic belt on loamy soils corresponds to sclerophyllous shrublands with Chamaerops humilis, Pistacia lentiscus, Quercus coccifera, Rhamnus lycioides, Rhamnus oleoides subsp. assoana, etc., with scattered pines (Pinus halepensis). These vegetation types are included in the Chamaeropo humilis-Rhamnetum lycioidis association (Table 5.1, row 5; Fig. 5.4). On heavy clay and sandstone soils the potential vegetation are plant communities dominated by brooms (Coronilla juncea, Genista ramosissima, Genista spartioides and Genista valentina subsp. jimenezii) of the Genisto-Phlomidion almeriensis alliance (Table 5.2; Fig. 5.5). Where those broom shrubs are abundant, the appearance of the landscape is very striking in springtime, by the yellow color and fragrance of their flowers.

Fig. 5.4
figure 4

The main thermomediterranean potential vegetation in the arid Southeast is the sclerophyllous Chamaeropo humilis-Rhamnetum lycioidis, in the photo dominated by the “palma chica” (Chamaerops humilis) (Calblanque, Murcia)

Full size image
Fig. 5.5
figure 5

The potential vegetation on clay and sandstone soils is dominated in the arid Southeast by brooms (Rhamno lycioidis-Genistetum murcicae), with Genista valentina subsp. jimenezii on Cabo Tiñoso (Murcia)

Full size image

In the mesomediterranean semiarid belt many thermophilic plants vanish, and the potential vegetation is the pine woodland of Querco cocciferae-Pinetum halepensis (Table 5.1, row 6).

On northerly faced and moister slopes, the thermomediterranean dry belt can be locally present and then the potential vegetation consists of oak forests (Quercus ilex subsp. rotundifolia), which can be divided into those of acid (Myrto communis-Quercetum rotundifoliae) and of basic substrates (Rubio longifoliae-Quercetum rotundifoliae) (Table 5.1, rows 7–8).

The mesomediterranean dry belt is confined to the upper elevations, such as some mountain summits (Sierras de Carrascoy, Almenara, Cabrera and Alhamilla), and has a potential vegetation of holm-oak forests (Quercetalia ilicis) (Table 5.1, rows 9–11).

3 Seral Scrub

The scrub of this territory covers most of the area in the hills and slopes, being a dominant element in the landscape. It is called tomillar (due to the abundance of thymes), and is an open-structured and low-sized vegetation but, at the same time, it is extremely diverse and rich in endemic species and vegetation types (Alcaraz and Delgado 1998). The numerous associations are grouped in the endemic Anthyllidetalia terniflorae order (Table 5.3; Fig. 5.6), except those on gypsum soils which belong to the Gypsophiletalia struthium order (Table 5.4) and a relict patch of the alliance Lavandulo lanatae-Genistion boissierii (order Rosmarinetalia officinalis) in the upper elevations such as the Carrascoy and Alhamilla mountain summits.

Table 5.3 Murcian-Almerian thyme-brushwoods (excluded those of gypsum soils)
Full size table
Fig. 5.6
figure 6

Seral scrublands (“tomillares”) are very diversified in the arid Southeast, and are mainly represented by the endemic order Anthyllidetalia terniflorae (Stipo tenacissimae-Sideritidetum leucanthae in the vicinity of Agost, Alicante)

Full size image
Table 5.4 Gypsicolous thyme-brushwoods (Gypsophiletalia)
Full size table

According to the detailed study of Alcaraz and Delgado (1998), the order Anthyllidetalia terniflorae encompasses three alliances:

  • Thymo moroderi-Sideritidion leucanthae: chamephytic thyme-brushwoods, South Murcia, Alicante and Almería, on loamy and rocky soils usually avoiding the salt-rich soils of marly depressions and coastal zones affected by salinity (Table 5.3, rows 1–12).

  • Sideritidion bourgeanae: thyme-brushwoods of the North Murcia and Murcia-Manchego subsectors (Table 5.3, rows 13–14).

  • Anthyllido-Salsolion papillosae: thyme-brushwoods of subsaline marly and phyllite substrates as well as of coastal zones affected by salt spray due to sea breeze. It is present all over the Murcia-Almería province (Table 5.3, rows 15–19).

On the Carrascoy and Almenara summits, up to 900 m, Peinado et al. (1992) found some relict communities of thyme-brushwoods related with those of the Sierra Espuña (Manchego-Espuña) and belonging to the association Teucrio webbiani-Helianthemetum origanifolii, of the Lavandulo lanatae-Genistion boissieri alliance. They also detected some vestiges of Convolvulo lanuginosi-Lavanduletum lanatae (Lavandulo lanatae-Genistion boissieri), on calcareous outcrops of the upper levels of the Sierra de Alhamilla in the mesomeditarranean level, a community type related to the western Alpujarras-Gádor sector (Baetic province).

Gypsaceous substrates are common in the Murcia-Almería province. They occur as scattered spots, isolated from each other, and thus they have been very favorable sites for the evolution of endemic taxa. The characteristic vegetation consists of brushwoods of the order Gypsophiletalia struthium, dominated by chamaephytes, some of which are widely distributed in the Iberian Peninsula gypsum outcrops (Gypsophila struthium subsp. struthium, Helianthemum squamatum, Lepidium subulatum, Ononis tridentata, etc.), while others have very limited ranges (Coris hispanica, Helianthemum alypoides, Herniaria fruticosa subsp. erecta, Santolina viscosa, Teucrium balthazaris, Teucrium lepicephalum, Teucrium libanitis and Teucrium turredanum). The Thymo-Teucrion verticillati alliance is endemic of the province (Alicante-Murcia & East Almería) (Table 5.4, rows 1–3), while in the West Almería subsector those thyme-brushwoods are represented by the alliance Lepidion subulati, with an endemic suballiance (Gypsophilo-Santolinenion viscosae) (Table 5.4, rows 4–6).

On siliceous soils, in the mesomediterranean areas with a dry ombroclimate, the seral scrub is dominated by Cistus ladanifer (jara pringosa) and Cistus albidus, with other less abundant species, such as Cistus salviifolius, Lavandula stoechas, Teucrium compactum subsp. compactum, etc. These brushwood are confined, in the Murcia-Almería province, to small areas in mountains above 700 m, mainly in the Almería sector (sierras of Alhamilla, Carboneras and Almenara), however, they reach, floristically impoverished, the Northern slope of the Sierra de Carrascoy, in the South Murcia subsector. These jarales belong to the Thymo gracilis-Cistetum ladaniferi association, and widely occur in the Baetic biogeographical province.

In thermomediterranean shaded areas and northern slopes of hills, the soils can have a neutral pH and the seral scrub is dominated by Cistus monspeliensis, looking as a jaral or silicolous Cistus garrigue (Calblanque, Carrascoy mountain, etc.), but the rest of the species are typical of base-rich soils. For that reason, despite its physiognomy, those thermophylous “jaral” brushwoods belong floristically to the order Anthyllidetalia terniflorae.

4 Grasslands

In the Murcia-Almería grasslands we can distinguish two main groups: that dominated by perennial grasses (class Lygeo-Stipetea), and that of pastures dominated by therophytic plants (class Helianthemetea guttati) occurring at open spaces between patches of other vegetation types.

4.1 Perennial Grasslands

The Murcia-Almería landscape, especially in the inframediterranean, thermomediterranean and lower mesomediterranean belts under semiarid conditions, is strongly influenced by the conspicuous occurrence of both esparto fields (Stipa tenacissima) of the Stipion tenacissimae alliance (Table 5.5, row 1; Fig. 5.7), and albardín fields (Lygeum spartum) of the Agropyro pectinati-Lygeion sparti alliance (Table 5.5, row 2). The former develop on dry soils, slopes and plains, not affected by soil hydromorphy, while the latter occur on valley bottoms and floodplains with a certain amount of edaphic moisture.

Table 5.5 Perennial grassland of the Murcia-Almería province
Full size table
Fig. 5.7
figure 7

Esparto fields (Lapiedro martinezii-Stipetum tenacissimae) are widespread in the arid landscapes of the Southeast (slopes in the vicinity of Alhama de Murcia, Murcia)

Full size image

At higher elevations, on Murcia-Almería mountains under mesomediterranean dry conditions, grasslands are represented by the Festucion scariosae alliance, with two associations (Table 5.5, rows 3 and 4): the Daphno hispanicae-Festucetum capillifoliae (South Murcia and East Almería subsectors), with a levantine and manchegan optimum, and the Dactylido hispanicae-Festucetum scariosae (West Almería subsector), with a Baetic optimum. Other perennial grasslands dominated by Brachypodium retusum (Phlomido lychnitidis-Brachypodion retusi alliance), of smaller size, are widespread on all types of soils, especially under pine forests (Table 5.5, row 5).

4.2 Annual Pastures

A good representation of annual pastures is only to be seen in wet years with substantial spring rains, and they develop within the open areas between the perennial vegetation. In the Murcia-Almería province they occur as annual grasslands rich in Iberian-African species, some of which being the only European populations (Aristida adscensionis, Asphodelus tenuifolius, Eryngium ilicifolium, Euphorbia dracunculoides subsp. inconspicua, Koelpinia linearis, Leysera leyseroides, Limonium lobatum, Neotorularia torulosa, Neurada procumbens, Notoceras bicorne, Plantago notata, Plantago ovata, Pteranthus dichotomus, Spergula fallax, etc.), and others being endemics (Centaurium rigualii, Chaenorhinum grandiflorum subsp. carthaginense, Euphorbia medicaginea, Linaria benitoi, Linaria nigricans, Linaria oligantha, Moricandia foetida, Pallenis hierochuntica, Senecio flavus, etc.). Those annual grasslands belong mainly to the Stipion retortae alliance (Table 5.6, rows 1–11; Fig. 5.8). On gypsy soils there are some specialists, such as Campanula fastigiata, Chaenorhinum grandiflorum subsp. grandiflorum and Chaenorhinum rupestre, and the grasslands are included in the Sedo-Ctenopsion gypsophilae (Table 5.6, rows 13–14). At some mountain summits (Carrascoy, Almenara, Cabrera and Alhamilla), in the mesomediterranean dry belt, annual grasslands are dramatically different, with species as Arabis auriculata, Cardamine hirsuta, Cerastium gracile, Erophila verna and Hornungia petraea, characteristics of the mesophilous association Saxifrago tridactylitae-Hornungietum petraeae (Trachynion distachyae) (Table 5.6, row 15).

Table 5.6 Therophytic non-nitrophilous communities in the Murcia-Almería province
Full size table
Fig. 5.8
figure 8

Annual pastures are very diversified and show strong floristic relations with the North African ones (Stipo capensis-Diplotaxietum lagascanae on a plot dominated by Moricandia foetida, vicinity of Tabernas, Almería)

Full size image

5 Coastal Vegetation

5.1 Dune Ecosystems

Sandy shores have been severely altered in the territory by tourism development. However, dune ecosystems are still well preserved along several stretches of the Murcia-Almería coast (Sierra Helada, Arenales de San Pedro del Pinatar, Cabo de Gata, Punta Entinas, Punta del Sabinar, etc.).

The gradient from the beaches on the coastline to the inner fixed dunes is expressed by the sequence of plant communities as described now. In the first band, close to the sea, the annual community of Salsolo kali-Cakiletum aegyptiacae establishes in the band where organic remains (mainly of Posidonia oceanica) accumulate and nitrification occurs. Next comes the band on very mobile sand, occupied by the Cypero mucronati-Elytrigietum juncei. The third band develops on the mobile crests of dunes, the Medicagini marinae-Ammophiletum australis subass. lotetosum cretici. The semi-stabilized sand dunes (grey dunes) are occupied by the chamaephytic community of Loto cretici-Crucianelletum maritimae, with the psammophilous annual association Triplachno nitentis-Silenetum ramosissimae in clearings of this low scrub. Finally, the completely stabilized sand biotopes are covered by thyme-brushwoods of the order Anthyllidetalia terniflorae (Anthyllido terniflorae-Teucrietum dunensis in the Alicante subsector, Helianthemo marminorensis-Teucrietum dunensis in the South Murcia subsector, Teucrio belionis-Helianthemetum scopulori in the Almería sector), with annual pastures in clearings (Erodio laciniati-Maresietum nanae in the Alicante-Murcia sector and East Almería subsector, Wahlenbergio nutabundae-Loeflingietum pentandrae in the Cabo de Gata and West Almería subsectors).

The potential natural vegetation of fixed coastal dunes (thermomediterranean semiarid stage) are communities of Juniperus macrocarpa (Coremato albi-Juniperetum macrocarpae) in the Alicante subsector (Sierra Helada, Benidorm), and the Juniperus turbinata association (Rhamno angustifoliae-Juniperetum turbinatae) in scattered areas of the South Murcia subsector (San Pedro del Pinatar to Cabo de Palos) and West Almería subsector (Punta Entinas-Punta del Sabinar).

5.2 Maritime Cliffs

Maritime cliffs comprise sloping to vertical faces of the rocky coastline where a break in slope is formed by slippage and/or coastal erosion. In the Murcia-Almería province two main plant communities appear, one non-nitrophilous (Limonio cossoniani-Lycietum intricati), dominated by Crithmum maritimum, Helichrysum stoechas subsp. caespitosum, Limonium cossonianum and Pallenis maritima, and the other ornithocoprophilous, on cliffs where gulls and other seabirds nest (Withanio frutescentis-Lycietum intricati), dominated by Lycium intricatum, Salsola oppositifolia and Withania frutescens. Maritime cliffs are best developed, from North to South, in the Sierra Helada (Benidorm, Alicante), the coast between the capes of Palos and Tiñoso (Cartagena) and between Carboneras and Cabo de Gata (Almería).

5.3 Saltmarshes

The Murcia-Almería province has large tracts of saltmarshes, both in coastal and in inland areas (salt plains and wadis on marls). A typical and complete zonation of saltmarshes includes up to five different belts of plant communities from the humid to the dry salty soils (Fig. 5.9).

Fig. 5.9
figure 9

Saltmarsh vegetation is common in the lower parts of valleys, on dry soils (right side of the picture, with the Limonio caesio-Lygeetum sparti) and on wet soils (center of the picture, with the Cistancho phelypaeae-Arthrocnemetum fruticosi). El Ajauque, Fortuna (Murcia)

Full size image

The lower part of the saltmarsh, under permanent inundation, is occupied by communities of rushes (Juncus maritimus) of the association Elymo elongati-Juncetum maritimi. The next step in the saltmarsh is occupied by communities of Sarcocornia perennis subsp. alpini (Sarcocornietum alpini), being under submersion with salty water from autumn to winter; in the same biotopes the annual community Salicornietum emerici is also found. The next step in the halophilous geosigmetum is occupied by the Cistancho phelypaeae-Arthrocnemetum fruticosi, a dense community dominated by the nanophanerophyte Sarcocornia lagascae, and in open stands by the annual association of the Suaedo spicatae-Salicornietum patulae. The next higher community along the elevational gradient can be the Frankenio corymbosae-Arthrocnemetum macrostachyi on loamy soils, a plant community dominated by Arthrocnemum macrostachyum, or, on sandy soils, by Halocnemum strobilaceum (Frankenio corymbosae-Halocnemetum strobilacei). The transition between the humid saltmarsh and the dry one is the habitat of an association dominated by Suaeda vera (Cistancho phelypaeae-Suaedetum verae).

The outer part of the saltmarshes is not affected by submersion with salty water. These areas are colonized by communities of Lygeum spartum and/or species of the genus Limonium (Limonium angustebracteatum, Limonium caesium, Limonium cossonianum, Limonium delicatulum, Limonium furfuraceum, Limonium insigne, Limonium parvibracteatum, Limonium santapolense, Limonium supinum, Limonium tabernense, etc.). The six associations of this belt in saltmarshes are included in the alliance Lygeo sparti-Limonion furfuracei that is almost endemic to the Murcia-Almería province. Finally, on the deeper saltmarsh soils, there are stands of tamarisk (Inulo crithmoidis-Tamaricetum boveanae).

Nowadays, the best preserved saltmarshes are located at El Alted and Santa Pola (Alicante), San Pedro del Pinatar, Calblanque, Águilas and Fortuna (Murcia), and at Vera and to West of Cabo de Gata (Almería).

6 Rupicolous Vegetation

Most of the rocky places of the Murcia-Almería province are composed of limestone or dolomite, and host many endemic plants. Settling into deep fissures that give access to large pockets of soil permits establishing an open vegetation composed of large shrubs, some sclerophyllous and others brooms, of the class Quercetea ilicis (Table 5.7, rows 1–4). On rocky slopes with protruding ledges having still some soil, the cerrillar grassland, dominated by Hyparrhenia sinaica (Table 5.7, row 5), covers significant areas being a very important association of the rocky landscapes (Lygeo-Stipetea).

Table 5.7 Main rupicolous associations of the Murcia-Almería province
Full size table

The chasmophytic (growing in fissures in rocks) vegetation on pavements is dominated by Satureja obovata subsp. canescens, Hypericum ericoides and Dianthus broteroi subsp. valentinus, characteristic taxa of the Saturejo canescentis-Cistetum albidi association (Table 5.3, row 1, Anthyllidetalia terniflorae). More diversified is the chasmophytic vegetation inhabiting narrow fissures in more or less vertical cliffs, with several associations of biogeographical importance (Table 5.7, rows 6–9). Crevices of the overhanging cliffs and the ceiling of some small caves are inhabited by the Centaureo saxicolae-Lafuenteetum rotundifoliae association, characterized by the remarkable Murcia-Almería endemic Lafuentea rotundifolia (Table 5.7, row 10). The chasmochomophytic vegetation in earth-accumulating, wide cracks is characterized by Lapiedra martinezii and the fern Cheilanthes vellea (Lapiedro martinezii-Cosentinietum velleae), a species capable of drying up almost completely under long and deep drought and reviving in a few minutes after a shower (poikilohydrous species) (Table 5.7, row 11). The chomophytic vegetation, rooted in soil resting on rocks slightly inclined, is represented by the Sedetum micrantho-sediformis association, dominated by succulent-leaved plants (Table 5.7, row 12). The chasmophytic vegetation of nitrified walls, mostly in areas under noteworthy human influence, is represented by the Parietarietum judaicae on dry walls, while on shady and moister walls the characteristic associations is the Cymbalarietum muralis (Table 5.7, rows 13–14).

7 Riparian Vegetation

There is only one true river in the area, the Segura, that traverses the Murcia-Almería province between Calasparra (Murcia) and Guardamar del Segura (Alicante). On the river banks and the fluvial terraces surrounding the Segura, there are a few remains of its riparian vegetation, which is more related to that of the North African rivers than to the European ones (Alcaraz et al. 1997). However there are many temporary streams and creeks, locally called ramblas, where the vegetation is rich in bushes and thickets of the Nerio-Tamaricetea class.

As highlighted by Alcaraz et al. (1997), Murcia-Almería riparian forests and shrublands belong, as in the Maghreb, to the Nerio-Tamaricetea class (Lonicero biflorae-Populetum albae), not to the Querco-Fagetea. Another African characteristic is the absence of willow groves in the first riparian vegetation zone. From the river’s edge the following sequence of plant communities can be found: helophytic reedbeds (Typho-Schoenoplectetum tabernaemontani) and the poplar riparian forest (Lonicero biflorae-Populetum albae; Fig. 5.10). Other seral communities are those of rush (Holoschoenetum vulgaris), evergreen grasslands (Brachypodietum phoenicoidis), tamarisk groves (Saccharo ravennae-Tamaricetum canariensis; Fig. 5.10) and brambles with honeysuckle (Rubo ulmifolii-Loniceretum biflorae).

Fig. 5.10
figure 10

The riparian forests of the arid Southeast belong to the Nerio-Tamaricetea (Lonicero biflorae-Populetum albae). In the picture there are also woodlands of tamarisks (Saccharo ravennae-Tamaricetum canariensis) and palm trees (Phoenix dactylifera), introduced by man, contribute to accentuate the similarities with North African landscapes. (Río Segura, Archena, Murcia)

Full size image

In the widespread ephemeral watercourses (ramblas), the vegetation varies greatly depending on the characteristics of the substrate and the degree of permanence of running water. The most common woody species are tamarisks (Tamarix canariensis, Tamarix africana), on loamy and clay soils (Saccharo ravennae-Tamaricetum canariensis), which can be subsaline (Agrostio stoloniferae-Tamaricetum canariensis subass. suaedetosum verae) or saline (Inulo crithmoidis-Tamaricetum boveanae). There are also oleander- (Nerium oleander-) dominated shrublands, which can develop on gravelly (Zizipho loti-Nerietum oleandri) or stony to rocky soils (Rubio longifoliae-Nerietum oleandri). When in full bloom the oleanders fill the ramblas with color, standing out conspicuously in the arid landscape. Also the occurrence of scattered populations of the Iberian palm (Phoenix iberica) in clayey, subsalty ramblas is remarkable; it gives them a truly African appearance.

8 Nitrophilous Vegetation

Nitrophilous bushes are another outstanding feature of the Murcia-Almería province, with a good number of associations belonging to the Haloxylo-Atriplicion alliance, on dry soils, and almost exclusive to the area, as well as some other bushes of the subhalophilous alliance Salsolo oppositifoliae-Suaedion fruticosae.

The Haloxylo-Atriplicion associations encroach on abandoned fields, and at crop and roads margins and other disturbed areas in which soil hydromorphy is absent. The best characteristic species in the Murcia-Almería province are Artemisia barrelieri, Artemisia lucentica, Atriplex glauca, Capparis sicula subsp. sicula, Capparis zohary, Haloxylon salicornicum (= Hammada articulata), Launaea arborescens, Salsola vermiculata and Salsola genistoides. The Salsolo oppositifoliae-Suaedion fruticosae associations also settle in disturbed areas but on soils with some hydromorphy and salinity. The main species in the Murcia-Almería area are Atriplex halimus, Lycium intricatum, Salsola oppositifolia, Suaeda pruinosa, Suaeda vera and Withania frutescens.

9 Human Influence

The landscape of the Murcia-Almería area is quite impressive because of the degradation and erosion observed everywhere as a result of a long human pressure throughout history, combined with a weak recovery capability of the aridity-adapted natural vegetation (Alcaraz et al. 1989, 1991; Alcaraz and Peinado 1987; Peinado et al. 1992).

The green color of the irrigated valley bottoms contrasts strongly with the arid appearance of the surrounding landscape. Mountains, slopes and plains above the floodplain of the Segura river are characterized by their ocher color and their sparse vegetation cover, which is still submitted to the pressure of sheep and goat husbandry, leaving a high proportion of the soil uncovered.

Arboreal and herbaceous crops are very important in all the areas irrigated by the waters of the Segura river, being part of the irrigation water brought in from the Tagus river. Some of the areas are prosperous, as those with the citric trees (oranges and, especially, lemons) while others, such as those with figs and mulberries, are declining although they were relevant in the past until not to so long ago. When salinity increases, some crops, such as barley, cotton, sweet pepper, tomato and even pomegranate, can still be cultivated. Along the fences and borders of the properties, palm trees grow successfully (Alcaraz 1991). Nowadays a prosperous agriculture with irrigation has developed under favorable climatic conditions, with an almost total absence of frost, with up to four yields per year: artichoke, broccoli, cauliflower, celery, cucumber, eggplant, endive, lettuce, melon, sweet pepper, spinach, tomato, watermelon, zucchini, etc. Some of these cultures are grown in plastic greenhouses. However, although intensive agriculture is widespread and dominant, in recent years organic farming is increasing in extent and recovering traditional varieties of arboreal and herbaceous crops.

With regard to cattle, goats and sheep are often grazing in the fields, after harvesting, as well as on the hills, while numerous pigs are raised in barns. Some native livestock breeds are being recovered, such as pigs (chato murciano), goats (cabra murciano-granadina), sheep (oveja segureña) or chicken (gallo murciano).

Forestry in the Murcia-Almería area focuses on protecting soil from erosion and desertification, rather than timber production, due to the slow growth of trees.

The effects of the mining industry, today in clear decline, are evident in the coastal areas of Cartagena, Mazarrón (Murcia) and Rodalquilar (Almería). The minerals of this area (iron, zinc, lead, gold and silver) attracted many people since antiquity: Phoenicians, Greeks, Carthaginians, Romans. The regeneration of these zones remains a task for the future.

Coastal tourism is highly developed in the area, especially on the eastern (Alicante) and the western coasts (Almería), and it is an important resource for the economy of the Murcia-Almería area. But as a result, so many coastal areas are showing a very disturbed vegetation.

10 Vegetation Series

According to the previous sections, there are 12 climatophilous sigmeta that occur in the arid southeast:

  1. 1.

    Mayteno europaei-Periploco angustifoliae sigmetum

  2. 2.

    Zizipho loti sigmetum

  3. 3.

    Gymnosporio europaei-Zizipho loti sigmetum

  4. 4.

    Chamaeropo humlis-Rhamno lycioidis sigmetum

  5. 5.

    Rhamno lycioidis-Genisto murcicae sigmetum

  6. 6.

    Thymelaeo valentinae-Genisto ramosissimae sigmetum

  7. 7.

    Rubio longifoliae-Querco rotundifoliae sigmetum

  8. 8.

    Myrto communis-Querco rotundifoliae sigmetum

  9. 9.

    Querco cocciferae-Pino halepensis sigmetum

  10. 10.

    Asparago acutifolii-Querco rotundifoliae sigmetum

  11. 11.

    Paeonio coriaceae-Querco rotundifoliae sigmetum

  12. 12.

    Adenocarpo decorticantis-Querco rotundifoliae sigmetum

Maquis and brooms communities, with more or less scattered pine trees (Pinus halepensis), represent the potential vegetation for most of the Murcia-Almería province (Table 5.8, sigmeta 1–6 and 9), extensively replaced by scrublands (tomillares) and perennial grasslands (esparto grass), which are the most abundant types of vegetation as a result of prolonged human action in the territory. Of particular importance for its richness of endemic plants are the gypsicolous thyme-brushwoods, of the Order Gypsophiletalia.

Table 5.8 Main associations and alliances of the Murcia-Almería province climatophilous sigmeta
Full size table

In the open areas between the scrublands and grasslands appear, from autumn to spring, annual grasslands of North African origin (Stipion capensis) or, on gypsum soils, Spanish endemic gypsicolous annual grasslands (Sedo-Ctenopsion gypsophilae).

In the few mountains over 700 m (Carrascoy, Almenara, Cabrera and Alhamilla mountains) some habitats can be located in the dry ombroclimate, with a potential vegetation of oak forest (Table 5.8, sigmeta 10–12); but there are also thermomediterranean areas with oak forest potential in places protected from strong insolation due to their orientation to the North (Table 5.8, sigmeta 7 and 8).

The main associations and alliances of each sigmetum are detailed in Table 5.8.