Classification of the Mediterranean lowland to submontane pine forest vegetation

Gianmaria Bonari,Ilona Knollová,Jiří Danihelka,Milan Chytrý,Erwin Bergmeier,Tiago Monteiro‐Henriques,Süleyman Çoban,Claudia Angiolini,Emiliano Agrillo,Ali Kavgacı,Lubomír Tichý,Fotios Xystrakis,Željko Škvorc,Kryštof Chytrý,Federico Fernández‐González,Coşkun Sağlam,Alicia Teresa Rosario Acosta ,Carlos Neto ,Yakiv Didukh ,S.m Hennekens ,José Carlos Costa

doi:10.1111/avsc.12544

Abstract

AbstractAimVegetation types of Mediterranean thermophilous pine forests dominated by Pinus brutia, Pinus halepensis, Pinus pinaster and Pinus pinea were studied in various areas. However, a comprehensive formal vegetation classification of these forests based on a detailed data analysis has never been developed. Our aim is to provide the first broad‐scale classification of these pine forests based on a large data set of vegetation plots.LocationSouthern Europe, North Africa, Levant, Anatolia, Crimea and the Caucasus.MethodsWe prepared a data set of European and Mediterranean pine forest vegetation plots. We selected 7,277 plots dominated by the cold‐sensitive Mediterranean pine species Pinus brutia, Pinus halepensis, Pinus pinaster and Pinus pinea. We classified these plots using TWINSPAN, interpreted the ecologically and biogeographically homogeneous TWINSPAN clusters as alliances, and developed an expert system for automatic vegetation classification at the class, order and alliance levels.ResultsWe described Pinetea halepensis as a new class for the Mediterranean lowland to submontane pine forests, included in the existing Pinetalia halepensis order, and distinguished 12 alliances of native thermophilous pine forests, including four newly described and three informal groups merging supposedly native stands and old‐established plantations. The main gradients in species composition reflect elevational vegetation belts and the west–east, and partly north–south, biogeographical differences. Both temperature and precipitation seasonality co‐vary with these gradients.ConclusionsWe provide the first formal classification at the order and alliance levels for all the Mediterranean thermophilous pine forests based on vegetation‐plot data. This classification includes traditional syntaxa, which have been critically revised, and a new class and four new alliances. We also outline a methodological workflow that might be useful for other vegetation classification syntheses. The expert system, which is jointly based on pine dominance and species composition, is a tool for applying this classification in research and nature conservation survey, monitoring and management.

Highlights

Mediterranean coniferous tree taxa are included in the genera Abies, Cedrus, Cupressus, Juniperus, Pinus, and Tetraclinis
Four pine species can be considered Mediterranean in terms of their temperature requirements and distribution, which is confined to low- to mid-elevations: Pinus brutia, Pinus halepensis, Pinus pinaster and Pinus pinea (Barbéro et al, 1998; Quézel, 2000)
Pinus pinea alliances occur at different elevations, but while the Mediterranean Pinus pinea communities, including old-established plantations, are concentrated in coastal areas, native forests of Pinion pineae in the eastern Mediterranean are more frequently found at higher elevations of the meso-mediterranean belt with high precipitation seasonality (Figures 6 and 7b)

Summary

| INTRODUCTION

Mediterranean coniferous tree taxa are included in the genera Abies, Cedrus, Cupressus, Juniperus, Pinus, and Tetraclinis. Pinus halepensis is the most widespread Mediterranean thermophilous pine species (Mauri et al, 2016), but it is more common in the western Mediterranean Basin In most areas, it occurs not far from the coast but reaches about 2,000 m a.s.l. in the Eastern High Atlas. At least Pinus brutia and Pinus halepensis can form pure climax forests in a suitable climate (Feinbrun, 1959; Quézel, 2000; Boydak, 2004; Bonari et al, 2020) Another explanation lies in the fact that the native distribution of some pine species is contentious Carrión et al, 2000) This allows a clear ecological distinction between two major groups of tree pines in the Mediterranean Basin: Mediterranean thermophilous species (Pinus brutia, Pinus halepensis, Pinus pinaster and Pinus pinea) and mountain species (Pinus cembra, Pinus heldreichii, Pinus nigra, Pinus peuce, Pinus sylvestris and Pinus uncinata).

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Findings

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