New Contributions to the Ericion umbellatae Alliance in the Central Iberian Peninsula

Abstract

The study of heathlands dominated by Erica australis, E. umbellata and Cistus populifolius in the centre and west of the Iberian Peninsula allows us to separate the eight shrubland communities. The taxonomic analysis of E. australis distinguishes two subspecies: E. australis subsp. australis and E. australis subsp. aragonensis. The statistical treatment confirms the differences between the suballiances Ericenion aragonensis and Ericenion umbellatae. This ecological, bioclimatic, biogeographical and floristic study has allowed us to differentiate three new associations from the remaining five: TCp = Teucrio oxylepis-Cistetum populifolii nova. HEau = Halimio ocymoidis-Ericetum australis nova. DEu = Drosophyllo lusitanicae-Ericetum umbellatae nova. ECp = Erico australis-Cistetum populifolii Rivas Goday 1964. PCp = Polygalo microphyllae-Cistetum populifolii Rivas Goday 1964. HEa = Halimio ocymoidis-Ericetum aragonensis Rivas-Martínez 1979. HEu = Halimio ocymoidis-Ericetum umbellatae Rivas Goday 1964. UEu = Ulici eriocladi-Ericetum umbellatae.

1. Introduction

Humid and subhumid areas contain woodlands of Quercus broteroi (Cout.) Rivas-Martínez & C.Sáenz (Portuguese oak), Quercus canariensis and Quercus marianica Vicioso, Quercus suber L. (cork oak) and Quercus pyrenaica Willd. (Pyrenean oak.) [1,2,3], all originating within the vegetation community dynamic of the Ericaceae family: Arbutus unedo L., Erica australis subsp. australis L., Erica umbellata Loefl. ex L., Erica scoparia L., and some communities of the Cistaceae family, Cistus populifolius L. Until now these communities in the central-western Iberian Peninsula have been included in the associations Halimio ocymoidis-Ericetum aragonensis, Halimio ocymoidis-Ericetum umbellatae, Ulici eriocladi-Ericetum umbellatae, and Polygalo microphyllae-Cistetum populifolii [4,5,6,7,8,9,10,11,12,13].

Heathlands are one of the most extensive and important habitats on the planet [14,15], and are among the most representative plant communities on the European continent with an Atlantic bioclimate and influence [5,16]. These formations are linked to oceanic environments, with abundant rainfall and short periods of summer drought in the case of the southern Iberian Peninsula [14,17,18,19,20], and in acidic, oligotrophic soils subject to erosion and fire [21].

From a conservation point of view, these communities have received a different treatment on the Iberian Peninsula [15] and were considered as mere replacement stages [5,21], whereas in the rest of Europe these plant formations—which harbour less diversity—are more highly regarded [15] in conservation terms. In the Habitats Directive, Erica umbellata-dominated heaths correspond to code 4030 “European dry heaths”.

The associations dominated by Erica spp., Ulex spp. and Cistus populifolius are typical of subhumid and humid ombro-types and are consequently fragile in the face of climate change, since they are affected by the increase in temperature and rainfall irregularity, as are the endemic taxa in these associations, and consequently the endemic taxa present in mountain areas [22,23,24]. These thickets dominated by the genus Erica are typical of rainy environments and are at their optimum in temperate Europe, although they extend to the sub-Mediterranean mountains, and connect catenally towards dry-subhumid ombro-types, with micro-forests of Juniperus oxycedrus subsp. badia (H. Gay) according to Debeaux [25,26].

On the Iberian Peninsula, this type of habitat has encountered problems in its interpretation, largely due to its extension and its bioclimatic and biogeographical diversity. The classifications proposed have disregarded the typical Mediterranean heaths, with Atlantic nuances, of the southwest Iberian Peninsula, which are of enormous floristic and biogeographical interest [15]. It should be noted that, of the three heathland subtypes considered, these Mediterranean dry heaths are the richest in endemisms.

The associations studied should be considered habitats of interest for conservation, since they dominate the middle and high mountains and include rocky habitats and wetlands with a predominance of endemic, rare and in some cases threatened species such as Coincya longirostra (Boiss.) Greuter & Burdet, Digitalis mariana Boiss., Jasione crispa subsp. tomentosa, Jasione crispa subsp. mariana (A.DC.) Rivas Mart., Dianthus lusitanus Brot., Adenocarpus hispanicus subsp. argyrophyllus (Rivas Goday), Drosophyllun lusitanicum (L.) Solenopsis laurentia (L.) C. Presl, Pinguicula lusitanica L.

According to [22], Erica australis L. is highly variable; the species Erica aragonensis Willk. and Erica australis subsp. aragonensis (Willk.) Cout. Are not recognized and claimed to be a montane ecotype, although any convincing arguments to synonymise these taxa to E. australis are not provided; however, [23] the subsp. Aragonensis is accepted. In our opinion the character of extrorse anthers in the subsp. aragonensis compared to non-extrorse anthers in the subsp. australis is clear. We, therefore, maintain the subsp. aragonensis, which has a more northerly distribution than the subsp. australis.

The main objective of the present work is to highlight the plant diversity of scrubs dominated by different species of the genus Erica in the centre-south of the Iberian Peninsula within the Mediterranean climate domain. On the other hand, from the point of view of the sustainability of forests and accompanying shrublands, it is important to know how these heathlands provide the environmental conditions necessary for the establishment of plant stages of greater biomass. It is, therefore, necessary to know the diversity and structure of Mediterranean dry heaths for their conservation and sustainability over time.

2. Materials and Methods

2.1. Study Area

The territory in the study is located in the central-western Iberian Peninsula (Figure 1) and is dominated by siliceous materials, Palaeozoic slates, metamorphic quartzites and plutonic rocks (granite); it has a Mediterranean bioclimate with a thermo-type that ranges between the thermo- and the supra-Mediterranean, and an ombro-type between dry and humid.

2.2. Sampling

An analysis was made of 232 heathland relevés dominated by Erica umbellata, E. australis and Cistus populifolius in the centre and west of the Iberian Peninsula, obtained from our own field research (56 samples) and various publications (176 samples) (

Table 1. Origin of the vegetation samples used in this work.

Plant Community	Bibliography	N° of Relevés
SDl	Galán de Mera, A. (1993)	5
	Junta de Andalucía	2
	Quezel P. et. al. (1988)	5
TCp	Own relevés	18
	Rodríguez Marzal (2006)	3
TCl	Junta de Andalucía	1
	Velasco Negueruela, A. (1981)	6
	Own relevés	4
HEa	Own relevés	12
ECp	Rivas Goday, S. (1964)	5
	Belmonte M.D. (2008)	13
	Muñoz, A.F.; Santa-Bárbara, C. & Vicent, C. (2008)	24
	Rufo Nieto (2009)	13
PCp	Melendo Luque, M. (1998)	7
	Rivas Goday, S. (1964)	8
	Belmonte M.D. (2008)	13
HEu	Rivas Goday, S. (1964)	5
	Belmonte M.D. (2008)	16
	Melendo Luque, M. (1998)	4
	Muñoz, A.F.; Santa-Bárbara, C. & Vicent, C. (2008)	9
Ueu	Muñoz, A.F.; Santa-Bárbara, C. & Vicent, C. (2008)	4
	Rivas-Martínez, S. (1979)	8
	Rufo Nieto (2009)	4
	Junta de Andalucía	21
DEu	Own relevés	22

SDl = Saturejo salzmannii-Drosophylletum lusitanici. TCl = Teucrio mariani-Cistetum laurifolii. TCp = Teucrio mariani-Cistetum populifolii. HEau = Halimio ocymoidis-Ericetum australis. ECp = Erico australis-Cistetum populifolii. PCp = Polygalo microphyllae-Cistetum populifolii. HEa = Halimio ocymoidis-Ericetum aragonensis. DEu = Drosophyllo lusitanicae-Ericetum umbellatae. HEu = Halimio ocymoidis-Ericetum umbellatae. UEu = Ulici eriocladi-Ericetum umbellatae.

). These relevés belong to ten associations: SDl = Saturejo salzmannii-Drosophylletum lusitanicii; TCl = Teucrio mariani-Cistetum laurifolii; TCp = Teucrio oxylepis-Cistetum populifoli (Figure 2); HEau = Halimio ocymoidis-Ericetum australis; ECp = Erico australis-Cistetum populifolii; PCp = Polygalo microphyllae-Cistetum populifolii; HEa = Halimio ocymoidis-Ericetum aragonensis; DEu = Drosophyllo lusitanicae-Ericetum umbellatae; HEu = Halimio ocymoidis-Ericetum umbellatae; UEu = Ulici eriocladi-Ericetum umbellatae. For the authorship of the taxa, we have followed Flora Ibérica, Flora Western Andalusia and Eastern Andalusia Flora. For the authorship of syntaxa, we have followed [12].

Our own samplings were taken following the Braun-Blanquet method, modified by Van der Maarel [24].

2.3. Data Analyses

Subsequently, and based on the geographic and topographic information contained in these relevés, each sampling was geo-referenced and implemented in a geographic information system (GIS) using the corresponding maps (Appendix A). They were then matched with the place names and the rest of the data from the samplings in the bibliography in order to obtain the different climatic and bioclimatic variables for each sampling. The figures for altitude, orientation and slope were determined by plotting the previously geo-referenced points on a digital terrain map (DTM) with a pixel resolution of 30 × 30 metres for the points in Portugal and Morocco, and on a digital terrain model with a resolution of 10 × 10 metres for the points in Spain. The numerical values for altitude, orientation and slope were obtained from the DTM for each sampling point by means of numerical classification methods. An ascending hierarchical classification was applied for the ordination and comparison of the different samples using Ward’s distance. For a better understanding of the results, a multivariate ordination analysis was carried out by means of detrended correspondence analysis.

3. Results

We studied the communities of Erica umbellata Loefl. ex L., Erica australis L. subsp. australis, Erica australis L. subsp. aragonensis (Willk.) Cout. and Cistus populifolius L. in the central Iberian Peninsula. The statistical analysis of the communities dominated by these taxa (Figure 2, Figure 3, Figure 4 and Figure 5) reveals the existence of two groups, G1 and G2, corresponding to the suballiances Ericenion aragonensis Rivas Martínez 1979 and Ericenion umbellatae Rivas Martínez 1979. The association Polygalo microphyllae-Cistetum populifolii (PCp1-PCp8) was described by [1] for shady Silurian sites in Extremadura, whose relevés PCp1-PCp8 are far removed from our group of relevés and [7] for the eastern Sierra Morena, and from the relevés of [1] from which he describes the association Erico australis-Cistetum populifolii (ECp1-ECp5), and which have a more thermophilous character than the former (Figure 4).

The relevés dominated by C. populifolius in eastern Sierra Morena differ floristically from the communities described by [4] in Extremadura, as they quite frequently include Teucrium oxylepis (endemic) and Cistus laurifolius, which grow in shady sites and foothills more influenced by the cold winds from the Manchegan plateau. We therefore propose the association Teucrio mariani-Cistetum populifolii nova (

Table 2. Teucrio mariani-Cistetum populifolii nova.

Altitude	889	472	817	867	877	800	800	650	740	680	660	730	580	660	948	976	969	876	890	930	985
Area m2	200	200	100	200	200	100	150	150	200	200	150	100	100	150	100	100	100	100
Coverage %	90	85	80	80	90	75	90	80	90	85	75	70	75	80	60	55	65	60	55	75	50
Inclination %	8	25		20	8	20	20	10	15	20	20	25	10	20	10	10	10	15	30	20	0
Orientation	N	N		NW	NE	N	NW	N	W	NW	NE	W	NE	NW	SW	SW	NE	N	NW	N	-
Medium height veg. in m.	1.80	0.90	1.70	1.40	0.80										0.70	0.70	0.70	0.35
	TmCp01	TmCp02	TmCp03	TmCp04	TmCp05	TmCp06	TmCp07	TmCp08	TmCp09	TmCp10	TmCp11	TmCp12	TmCp13	TmCp14	TmCp15 *	TmCp16	TmCp17	TmCp18	TmCp19	TmCp20	TmCp21
Characteristic association species
Teucrium oxylepis subsp. marianum															5	2	5	5	2	2	3
Cistus populifolius subsp. populifolius	4	5	5	5	4	5	5	4	4	4	5	4	5	4	4	2	5	2	3	+	3
Characteristic species of Ericion umbellatae
Erica australis subsp. australis						1	1		+	1		1	2	1	2	+		+		+	+
Halimium ocymoides	+								+		+		2			5
Polygala microphylla							2	1	+		+		1	+
Erica umbellata						2					+	1		+
Characteristic species of Calluno-Ulicetea
Pterospartum tridentatum subsp. lasianthum							+			+			+
Calluna vulgaris						1	1	+					+
Erica scoparia subsp. scoparia								+		1			+	+
Tuberaria lignosa							+	+		+		+
Characteristic species of Ulici-Cistion ladaniferi
Lavandula stoechas subsp. luisieri		1			2	2	1								+	1	1	+
Lavandula pedunculata subsp. sampaiana								1			1		1	+
Erophaca baetica				+					+	+				+
Lavandula stoechas subsp. stoechas																				+
Characteristic species of Lavanduletalia stoechadis and Cisto-Lavanduletea
Cistus ladanifer subsp. ladanifer	1	1	2	2	2		2	1	1	1	2	+	1	1	2		2	1		+	+
Cistus crispus			+																	3	2
Narcissus triandrus subsp. pallidulus															1	1	+		+
Cistus monspeliensis				1
Iberis linifolia				+
Cistus salviifolius		1						+	2	1		+		1							+
Halimium umbellatum subsp. viscosum					5										1		+			3
Cistus laurifolius	5			2	2											+
Characteristic species of Querceta ilicis class and lower units
Erica arborea			+			1	1	1	1	+	1	+	+	+		1		+
Arbutus unedo	1				+	+	1	+	2	+	1	+	1	+
Phillyrea angustifolia	+			1	+	+	1	1		+	+		+			+	+	+	+		+
Daphne gnidium					+			1	1	1			+				+	+	+	+	+
Quercus broteroi	+				+	1	1		+				+	+		+		+
Quercus suber						1	1	+	+		+							+	+		+
Doronicum plantagineum															2		2	1
Paeonia broteri	+	+		+											+			+	+
Teucrium fruticans																+		1
Jasminum fruticans				1
Lonicera implexa					+													+	+
Quercus rotundifolia					+														+		+
Rubia peregrina subsp. peregrina				+															+	+
Viburnum tinus									+		+								+
Juniperus oxycedrus subsp. badia			+															+
Lonicera periclymenum subsp. hispanica				+											+
Pistacia terebinthus									+			+
Sanguisorba hybrida																					+
Characteristic species of Cytisetea scopario-striati class and lower units
Cytisus scoparius subsp. bourgaei	1	+	1	1	1				1	+			1	1		+
Adenocarpus telonensis											1	+	1	+
Pteridium aquilinum																			2
Cytisus grandiflorus subsp. grandiflorus			+
Cytisus striatus subsp. striatus																					+
Characteristic species of Querco roboris-Fagetea sylvestris class and lower units
Cephalanthera longifolia		1			+													1
Geum sylvaticum																	1	1		+
Quercus faginea subsp. faginea																			2		+
Arenaria montana subsp. montana																		1
Tamus communis				+														+
Epipactis helleborine subsp. helleborine																		+
Epipactis helleborine subsp. tremolsii																					+
Quercus pyrenaica																		+
Sorbus torminalis																		+
Companion species
Pinus pinaster																			5	4	5
Rosmarinus officinalis	1			2	+			1		1		+
Thapsia villosa	+			+	+				1			1							2	+	+
Thymus mastichina		1		1												1		+			+
Carlina corymbosa subsp. corymbosa																			+	2	2
Agrostis capillaris x castellana																				3	+
Cistus albidus		+		2									+
Halimium halimifolium																			+	2	+
Castanea sativa																			2	+
Dactylis lusitanica		+	+	1
Holcus lanatus																				2	+
Rubus ulmifolius																		+	2
Asphodelus albus subsp. albus				+													1
Briza maxima																				2
Helichrysum stoechas				+															+	+	+
Sanguisorba verrucosa								1		+
Sedum forsterianum															1	+
Centaurea melitensis				1
Festuca rothmaleri																	1
Leucanthemum sylvaticum				1
Magydaris panacifolia				1
Origanum virens																		+	+	+
Avenula marginata subsp. sulcata																				+	+
Celtica gigantea																				+	+
Dactylis glomerata subsp. hispanica																			+		+
Ranunculus gramineus															+	+
Rosa pouzinii					+													+
Sanguisorba minor																				+	+
Andryala integrifolia																					+
Aristolochia pistolochia		+
Arrhenatherum elatius subsp. bulbosum					+
Campanula rapunculus				+
Cardamine hirsuta															+
Clinopodium vulgare subsp. arundanum																				+
Conopodium marianum				+
Dorycnium penthaphyllum	+
Eryngium tenue																			+
Iris planifolia				+
Linum suffruticosum subsp. suffruticosum				+
Picris comosa			+
Piptatherum miliaceum			+
Srophularia scorodonia																		+
Thapsia garganica			+
Tulipa sylvestris																		+

Typus *.

rel. TCp1-TCp18 typus rel. TCp15*).

The relevés corresponding to the association described by [5], Ulici eriocladi-Ericetum umbellatae (UEu1-UEu8), are clearly separated and floristically, ecologically, dynamically and biogeographically differentiated from the other communities of E. australis. The association Halimio ocymoidis-Ericetum aragonensis (HEa1-HEa15), described by [5] for the territories of Guadalajara and Segovia, shows significant differences from the heathlands of E. australis in the Marianica range due to the absence in Marianican territories of E. australis subsp. aragonensis, Luzula lactea (Link) E.Mey., Genista pilosa L., Deschampsia flexuosa subsp. iberica Rivas Mart. and Helianthemum pulverulentum Pers. We therefore propose the association Halimio ocymoidis-Ericetum australis nova (

Table 3. Halimio ocymoidis-Ericetum australis nova.

	HEau1	HEau2	HEau3	HEau *	HEau5	HEau6	HEau7	HEau8	HEau9	HEau10	HEau11	HEau12
Altitude m.	820	1022	1061	1249	1229	742	752	800	760	1160	800	750
Area m2	300	200	200	200	200	100	200	200	200	400	100	200
Coverage %	80	95	80	90	80	90	100	75	90	85	95	95
Slope %	15	8	8.5	8	10	8.5	4	20	20	25	20	20
Orientation	E	NE		NW	N		E-SE	N	N	S	N	S
Medium height veg. in m.	1	1.5	1.5	1.5	1.20	0.70	1.8	1.0	1.0	1.0	1.0	1.0
Characteristic association species and higher syn-taxonomic units
Erica australis	4	5	4	5	4	5	5	5	5	4	5	5
Halimium ocymoides	1	1	1	2	1	1	1	1	+	2	1	1
Cistus poulifolius	+	+	1	1	1	1	4		1	1	1	2
Erica umbellata	2	1		2		4	1	1	1			1
Lavandula luisieri	+		1				+	1		1	1	2
Calluna vulgaris						2			1	1	1	1
Polygala microphylla		+			+		+					+
Tuberaria lignosa		+		+						1
Erica scopara						2	2
Pterospartum tridentatum										1
Companion species
Cistus ladanifer	2	2	2	2	1	2	+	1	2	2	2	2
Arbutus unedo	+	+	1			+	1		+	+		+
Rosmarinus officinalis	+					+	1	2	+		2	2
Erica arborea	1		2	+					+	+		+
Phillyrea angustifolia	+		1			+	+		+		2
Quercus broteroi							+		+	+		+
Festuca elegans		+	1	+	2
Daphne gnidium		+					1					1
Quercus suber								+		+		+
Cistus salvifolius			+	+	+
Avenula sulcata subsp. occidentalis		1	1
Juniperus oxycedrus subsp. badia	+	+
Quercus pyrenaica		+			+
Thymus mastichina						+			1
Asphodelus albus				1	1
Quercus rotundifolia				+							+
Saxifraga granulata		+
Hypochaeris radicata		+
Thapsia villosa		+
Rumex angiocarpus		+
Cytisus scoparius subsp. bourgaei			+
Cistus crispus						+
Ranunculus sardous subsp. aleae			+
Klasea abulensis			+
Arrhenatherum elatius subsp. bulbosum				+
Narcissus triandrus					+
Arrhenatherum album					+
Cardamine hirsuta							2
Scirpus holoschoenus						+
Salix atrocinerea						+
Osyris alba							1
Teucrium haenseleri							+
Cytisus multiflorus							+
Pistacia terebinthus								+
Juniperus oxycedrus										+

Typus *.

rel. HEau1-HEau11, typus rel. HEau4*), which has a more southerly character than the previous association, for supra-Mediterranean environments in the eastern Mariánico-Monchiquensean sector; this heathland represents a dynamic stage of the woodlands of Sorbo torminalis-Quercetum pyrenaicae. This association is statistically close to Erico australis-Cistetum populifolii; however, the latter has a more eastern and thermophilous character ([4], Table 67, page 446).

In the group of communities of E. umbellata, the relevés given by [4,5] in the Sierra de San Pedro (Cáceres) and Herrera del Duque (Badajoz), León and Zamora are gathered in a single compact group (HEu12-HEu21) corresponding to Halimio ocymoidis-Ericetum umbellatae; this association was described by [4] in highly oligotrophic and nutrient-poor soils. It has floristic, dynamic and biogeographical differences with the communities of Erica umbellata in the eastern Sierra Morena; the Leonese and Zamoran territories include the species Halimium alysoides, E. australis subsp. aragonensis, Ulex minor, Genista micrantha, and Agrostis setacea, which have a more oceanic character and are not present in the eastern Sierra Morena. The relevés of [7,10] are grouped with those taken recently by us in the province of Ciudad Real, where they include E. umbellata, Halimium ocymoides, Tuberaria lignosa, Pterospartum tridentatum, Drophyllum lusitanicum, Lavandula pedunculata and occasionally Festuca elegans, Coincya longirrostra and Juniperus oxycedrus subsp. badia. We therefore propose the association Drosophyllo lusitanicae-Ericetum umbellatae nova (

Table 4. Drosophyllo lusitanicae-Ericetum umbellatae nova.

	DEu1	DEu2	DEu3	DEu4	DEu5	DEu6 *	DEu7	DEu8	DEu9	DEu10	DEu11	DEu12	DEu13	DEu14	DEu15	DEu16	DEu17	DEu18	DEu19	DEu20	DEu21	DEu22
Altitude m.	795	1233	982	1042	1051	1061	1074	1095	742	599	830	1010	800	730	800	800	700	750	720	750	760	740
Area m2	300	400	100	50	10	40	20	40	100	100	200	100	200	200	200	200	300	200	150	200	150	100
Coverage %	40	60	80	50	80	70	70	90	80	80	90	95	85	80	80	75	75	80	80	75	85	90
Slope %	12	20	4	6	8	8	6	4	10	8	30	5	15	15	15	30	35	30	25	10	10	15
Orientation	SW	N	S	NE	NE	NE	NE	NW	W	W	W	N-NE	N	N	N	S	S	W	SW	N	NE	NW
Medium height veg. in m.	0.80	1.5	0.70	0.40	0.60	0.50	0.40	0.50	0.25	0.35		0.60
Characteristic association species and higher syntaxonomic units
Erica umbellata	4	5	4	4	5	5	5	5	4	4	5	5	4	4	5	5	4	5	4	4	4	4
Halimium ocymoides	4	4	4	4	4	4	1	4	1	4	1	4	1	4	4	5	4	4	5	4	1	5
Erica australis	1	+	4	1	1	1	1	1	1	1	1	1	1	1	1	1	+	1
Drosophyllum lusitanicum		4	5	4	5	4	4	4
Cistus populifolius				1	1	+		1													+
Tuberaria lignosa		+						+											1		+	1
Lavandula luisieri										+			+		1
Pterospartum tridentatum subsp. lasianthum		1																	+	+		1
Calluna vulgaris									1				+		5	1		1	1	+	+	1
Erica lusitanica									+
Erica scoparia									+			+
Companion species
Cistus ladanifer	1	+	4		4	+	+	+	+	+	1	1	1	+	+	+	+	+	1	1	4	1
Rosmarinus officinalis	+											1	1	1		+	1	+	1	4	4	4
Lavandula stoechas subsp. sampaioana																			+	1		4
Briza máxima															1	+	1	+
Tolpis barbata											+		1	+		1
Petrorhagia prolifera															1	+	+
Cistus salvifolius									+											+	+	+
Asphodelus albus		+			+	+														+
Arrhenatherum bulbosum subsp. elatius		+
Jasione montana			+		+
Ranunculus gramineus				+
Xolanta guttata				+
Jasione crispa subsp. tomentosa					+
Lavandula pedunculata						+
Cytinus hypocistis								+
Scirpus holoschoenus									+
Salix atrocinerea
Genista hirsuta										+
Asphodelus microcarpus										+
Osyris alba										+
Gladiolus illyricus										+
Thymelaea villosa																				+		+
Adenocarpus telonensis																			+			+
Dactylis hispanica														1	1
Daphne gnidium												+							+		+
Arbutus unedo					+			+
Erica arborea	+
Phillyrea angustifolia						+

Typus*.

rel. DEu1-DEu22 typus rel. DEu6 *) growing on highly washed soils (distric lithosols) with a total absence of organic matter. This association is distributed throughout the eastern Mariánico-Monchiquensean sector.

4. Discussion

The study of heathlands dominated by Erica australis subsp. australis, subsp. aragonensis, E. umbellata and Cistus populifolius contributes eight different vegetation communities. Until now the heathlands in Luso-Extremaduran territories have been included in the known associations [4,5]. However, our recent studies in the province of Ciudad Real reveal floristic differences to the associations described previously. In the taxonomic study, [22,25] do not recognise E. australis L. subsp. aragonensis (Willk.) Cout., although [5,23] recognise the aragonensis variety.

Species in the genus Erica are always found in sub-humid–humid environments and appear in the dynamics of various types of Quercus from temperate and Mediterranean European areas [27,28,29], but always in acid-neutral pH substrates, never in Quercus forests on basic substrates [30]. In the degradation of these scrubs, either by human action or climate change [31,32,33,34]. They are replaced by species of the genus Cistus [24]; Cistus ladanifer is the species that replaces Erica australis and Erica umbellata in the studied territory.

The association TCp is a shrubland dominated by C. populifolius and is a cold vicariant community of PCp described by [4] for the more oceanic Extremaduran territories. The new association occupies the easternmost areas of the Mariánica mountain range, which receives the influence of the climate of the Manchegan plateau and comprises differential species such as C. laurifolius and the endemism Teucrium oxylepis subsp. marianum. These communities cannot therefore be included in the association PCp. [5] Lecto typifies the association HEu described by Rivas Goday in the province of Cáceres. The floristic and ecological differences make it inadvisable to include the communities dominated by E. umbellata from the eastern Maríanica range in this association, HEu, as they grow on extremely nitrogen-poor distric lithosols that allow the presence of Drosophyllum lusitanicum; the new association is therefore a soil vicariant of HEu. This same author describes the association HEa for the provinces of Segovia and Guadalajara, and gives the typus in the locality of Puerto de San Benito (Guadalajara) at an altitude of 1840 m. The floristic, bioclimatic and biogeographical differences lead us to propose the association HEau for the Luso-Extremaduran territories (

Table 5. Synoptic table: TCp = Teucrio oxylepis-Cistetum populifolii; HEau = Halimio ocymoidis-Ericetum australis; ECp = Erico australis-Cistetum populifolii; PCp = Polygalo microphyllae-Cistetum populifolii; HEa = Halimio ocymoidis-Ericetum aragonensis; DEu = Drosophyllo lusitanicae-Ericetum umbellatae; HEu = Halimio ocymoidis-Ericetum umbellatae.

	TCp	HEau	ECp	PCp	HEa	DEu	HEu	UEu
Halimium ocymoides	I	V	III	II	II	V	V	V
Erica australis	II	V	V			IV		II
Cistus ladanifer	IV	V	IV			V	II	II
Erica umbellata	I	II				V	V	V
Tuberaria lignosa	I	II				I	III	II
Cistus crispus	I	I	II					V
Lavandula luisieri	II	III	III			I		V
Erica scoparia	I	I		I		I	I	I
Cistus salvifolius	II	I				I		IV
Quercus rotundifolia	I	I	II	II			II	I
Calluna vulgaris	I	II		II	V	II	IV
Genista tridentata	I	I	III	II	I	II	V
Polygala microphylla	I	I		IV			I
Halimium umbellatum subsp viscosum	I		II		IV		I
Quercus pyrenaica	I	II			I		I
Erica arborea	III	II		IV	I	I
Cistus populifolius	V	V	V	V		I
Arbutus unedo	III	II	III	IV		I
Phillyrea angustifolia	III	III	IV	III		I
Daphne gnidium	II	I		II		I
Rosmarinus officinalis	II	III	I			II
Asphodelus albus	I	I				I
Arrhenatherum elatius subsp bulbosum	I					I
Ranunculus gramineus	I					I
Adenocarpus telonensis	I			III		I
Lavandula stoechas subsp sampaioana	I			III		I
Cistus laurifolius	I			II	I
Quercus suber	II	I	IV	III
Pistacia terebinthus	I	I	I	IV
Viburnum tinus	I		I	III
Dactylis lusitanica	I		II	I
Lonicera peryclimenum	I		I	III
Paeonia broteroi	I		I	I
Rubia peregrina	I		I	II
Lonicera implexa	I			II
Doronicum plantagineum	I			II
Cytisus grandiflorus	I			I
Cephalanthera longifolia	I			II
Arenaria montana	I			I
Tamus communis	I			III
Teucrium fruticans	I			II
Magydaris panacifolia	I			II
Astragalus lusitanicus	I			III
Conopodium marianum	I			II
Jasminum fruticans	I			I
Thapsia villosa	I
Cytisus scoparius subsp bourgaei	II	I	IV
Cardamine hirsuta	I	I	IV
Helichrysum stoechas	I		I
Srophularia scorodonia	I		I
Origanum vulgare subsp virens	I		I
Cistus albidus	I		I
Quercus broteroi	III	II
Thymus mastichina	I	I
Juniperus oxycedrus subsp badia	I
Teucrium oxylepis subsp marianum	I
Sedum forsterianum	I
Narcissus pallidulus	I
Cistus laurifolius	I
Geum sylvaticum	I
Festuca rothmaleri	I
Rubus ulmifolius	I
Rosa pouzinii	I
Epipactis helleborine	I
Sorbus torminalis	I
Tulipa sylvestris	I
Dorycnium penthaphyllum	I
Aristolochia pistolochia	I
Piptatherum miliaceum	I
Helminthotheca comosa	I
Thapsia garganica	I
Leucanthemum sylvaticum	I
Iberis linifolia	I
Centaurea melitensis	I
Campanula rapunculus	I
Iris planifolia	I
Linum suffruticosum	I
Cistus monspeliensis	I
Sanguisorba verrucosa	I
Teucrium haenseleri		I		I			I
Osyris alba		I		I		I
Narcissus triandrus		I				I
Scirpus holoschoenus		I				I
Cytisus multiflorus		I		I
Festuca elegans		I
Ranunculus sardous		I
Klasea integrifolia		I
Arrhenatherum album		I
Helictochloa marginata		I
Salix atrocinerea		I
Halimium lasianthum			III					I
Xolantha guttata			IV			I	I
Pteridium aquilinum			I	III				I
Urginea maritima			IV	IV			I
Sanguisorba hybrida			I					I
Phillyrea latifolia			I	III
Asparagus acutifolius			III	I
Senecio minutus			I	II
Phlomis purpurea			I
Genista polyanthos			III
Smilax mauritanica			III
Euphorbia nicaeensis			II
Myrtus communis			II
Pistacia lentiscus			I
Bupleurum fruticosum			I
Genista falcata			I
Ruscus aculeatus			I
Quercus canariensis			I
Digitalis purpurea subsp tomentosa			I
Saxifraga granulata subsp glaucescens			I
Asplenium adiantum-nigrum			I
Selaginella denticulata			I
Lunularia cruciata			I
Genista triacanthos				I				V
Thymelaea villosa				V		I		II
Drosophyllum lusitanicum						I
Quercus lusitanica				III
Teucrium scorodonia				IV
Anthericum baeticum				III
Ornithogalum pyrenaicum				IV
Silene psammitis				IV
Thapsia nitida				IV
Cistus psilosepalus				II
Genista tournefortii				II
Smilax aspera				II
Pterocephalus papposus				II
Halimium halimifolium				I
Halimium atriplicifolium				I
Quercus coccifera				I
Blechnun spicant				I
Agrostis castellana					I		II	II
Erica australis subsp aragonensis					V		I
Polytrichum piliferum					II		II
Avenula sulcata					III		I
Cladonia furcata					I		I
Jasione montana					I	I
Luzula lactea					V
Deschampsia flexuosa subsp iberica					V
Genista pilosa					III
Artostaphylos uva-ursi subsp crassifolia					II
Sedum brevifolium					II
Helianthemum apenninum					II
Lotus corniculatus subsp carpetanus					II
Vaccinium myrtillus					I
Jasione laevis subsp carpetana					I
Erica cinerea					I
Cetraria islandica					I
Fagus sylvatica					I
Nardus stricta					I
Hieracium pilosella					I
Plantago radicata					I
Festuca durandii					I
Juniperus nana					I
Thymus bracteatus					I
Genista hirsuta						I		I
Cytinus hypocistis						I	I
Jasione crispa subsp tomentosa						I
Lavandula pedunculata						I
Erica lusitanica						I
Asphodelus microcarpus						I
Gladiolus illyricus						I
Briza máxima						I
Tolpis barbata						I
Petrorhagia prolifera						I
Dactylis hispanica						I
Halimium alyssoides							III
Cladonia verticillata							II
Cladonia mediterranea							I
Agrostis setacea							I
Ulex minor							I
Genista micrantha							I
Agrostis truncatula							I
Ulex parviflorus subsp eriocladus								V
Pterospartum tridentatum								V
Festuca ampla								I

).

Syntaxonomical Checklist

CALLUNO-ULICETEA Br.-Bl. & Tüxen ex Klika & Hadac 1944

ULICETALIA MINORIS Quantin 1935

• Ericion umbellatae Br.-Bl., P. Silva, Rozeira & Fontes 1952
• Ericenion umbellatae Rivas-Martínez 1979
  • Halimio ocymoidis-Ericetum umbellatae Rivas Goday 1964
  • Ulici eriocladi-Ericetum umbellatae Rivas-Martínez 1979
  • Drosophyllo lusitanicae-Ericetum umbellatae nova

• Ericenion aragonensis Rivas-Martínez 1979
  • Polygalo microphyllae-Cistetum populifolii Rivas Goday 1964
  • Erico australis-Cistetum populifolii Rivas Goday 1964
  • Halimio ocymoidis-Ericetum aragonensis Rivas-Martínez 1979
  • Teucrio mariani-Cistetum populifolii nova
  • Halimio ocymoidis-Ericetum australis nova

5. Conclusions

This study reveals a set of new associations for scrub dominated by species of the genera Erica and Cistus. All these communities act as dynamic states of cork oak forests Quercus suber, Q. broteroi, Q. pyrenaica, Q. marianica and Q. canariensis, of which the forests of Q. pyrenaica and Q. canariensis are the most fragile, both because they are at the edge of the range and are threatened by climate change. It is therefore essential to protect these forest formations and their dynamic stages, constituted firstly by scrub of Arbutus unedo and secondly by heaths of Erica sp. and C. populifolius. Since all these plant communities are located in sub-humid or humid mountain environments, where a high rate of endemic, rare or threatened species thrive, protection measures must be put in place against fire and excessive livestock pressure. The territory dominated by these shrubs contains a high rate of endemisms, which is why their protection is necessary by subjecting these areas to sustainable development, with control of livestock.