Chilean vegetation linked to an international classification system

A comprehensive classification has linked all 125 mapped zonal vegetation units in Chile to the EcoVeg system developed for the International Vegetation Classification project, placing the country’s forests, woodlands, shrublands, grasslands, deserts and high-mountain communities within 13 divisions, 11 formations and 23 macrogroups. The exercise also generated a national macrogroup map intended to make Chilean vegetation more readily comparable across national borders and to show where the global classification may need refinement. The study is a classification and mapping analysis rather than a field experiment, and its authors note that links for less distinctly zonal vegetation remain provisional.

The work builds on the second edition of Chile’s vegetation classification and cartography, developed by Luebert and Pliscoff in 2017. Chilean government conservation agencies and organizations already use the national vegetation units as surrogates for ecosystems in systematic planning, including the identification of new protected areas. Researchers have also used them to examine climate-change effects, assess the impacts of Chile’s severe 2017 fires and establish categories of ecosystem risk based on International Union for Conservation of Nature guidelines. The new linkage extends that nationally useful framework toward the EcoVeg approach, which is intended to provide an international standard for classifying vegetation.

To make the correspondence, the researchers first assigned each zonal vegetation unit to an EcoVeg formation by combining coarse vegetation physiognomy with macroclimate. They then used the names and descriptions of the vegetation belts to evaluate biogeography, diagnostic species, growth forms, bioclimate, dynamics and climate-related hydrology. The main reference was the published list of American macrogroups, supplemented where necessary with proposed new units following established EcoVeg criteria. The macrogroup level was selected because the finer group level remains largely undeveloped in Latin America, although the authors believe some Chilean units may eventually fit better at that level. Chilean zonal vegetation units, or vegetation belts associated with broad climatic and geographic zones, formed the population of 125 units analyzed in the study.

Four formation classes account for Chile’s zonal vegetation. Forest and woodland vegetation occurs in central and southern Chile across climates ranging from Mediterranean to cold antiboreal conditions and includes sclerophyllous, deciduous, lauriphyllous and evergreen forests. Ten macrogroups in this formation class received 55 zonal units. Shrub and herb vegetation, discontinuously distributed through central Chile, the far north and Patagonia, includes thorny scrub, Patagonian grassland and moorland; 18 units were assigned to six macrogroups in four formations. Another 33 units fall within desert and semi-desert formations, chiefly in northern Chile but also in the Mediterranean climatic zone of the central Andes. Nineteen units of high-mountain scrub, grassland and forb vegetation were assigned to three macrogroups, bringing the zonal total to all 125 units.

The analysis proposed additions that recognize vegetation characteristics not adequately represented in the existing international list. The authors introduced a Mediterranean Forest and Woodland formation and a Chilean Mediterranean Forest and Woodland division to accommodate the sclerophyllous and deciduous forests of central Chile. They also proposed the Valdivian Temperate Conifer Forest and Woodland macrogroup within the Cool Temperate Forest and Woodland formation. Two additional units, Magellanian Antiboreal Deciduous Forest and Magellanian Antiboreal Evergreen Forest, were needed because the existing classification did not distinguish both evergreen and deciduous Magellanian forests under an antiboreal bioclimate. These proposals extend the international framework rather than merely applying it unchanged, providing specific units for vegetation that the authors concluded was either absent or insufficiently differentiated in the earlier macrogroup list.

Several mismatches emerged where physiognomy, climate and biogeography do not align neatly. Chilean formations and International Vegetation Classification formations are both largely based on physiognomic and ecological criteria, but the international system combines multiple previous classification approaches. The authors found a particular difficulty in deciding whether macroclimate or biogeography should take precedence at different levels. For example, forests dominated by Nothofagus pumilio and Nothofagus betuloides can display similar structure and occur in both temperate and antiboreal climates. They are placed in different regional divisions because of biogeography, then distinguished as deciduous and evergreen macrogroups through growth form and dominant species. The authors also questioned the global suitability of terms such as “Boreal” and “Alpine” in formations that occur in the Southern Hemisphere, suggesting that such names and others with the same problem should be revised to make the international system more globally applicable.

Central Chile provided a further test of the hierarchy because its Mediterranean-climate forests were accommodated within a broader warm-temperate formation that combined sclerophyllous and deciduous vegetation. The proposed Chilean division reflects differences in floristic composition and phylogenetic diversity from other parts of the country, and the authors suggest it could eventually include appropriate Mediterranean-climate units elsewhere, including parts of California, the Mediterranean basin, South Africa and Australia. They also proposed placing Mediterranean high-Andean scrub and grassland in the cool semi-desert formation rather than the tropical high-mountain formation used in the existing list. These judgments expose differences among climate definitions, including the seasonal Mediterranean bioclimate used in the Chilean classification and systems in which Mediterranean climates are classified within temperate zones. The authors note that alternative definitions may differ in hierarchical position and spatial extent, so these assignments are not entirely independent of the climatic system adopted.

Not every existing macrogroup could be matched cleanly. Some were absent from the Chilean inventory, including Southern Andean Montane Salt Marsh and Sechura Atacama Semi-Desert Cliff and Pavement, while others could not be identified confidently from the national descriptions. Xeric Puna succulent scrub, represented in Chile by locally abundant Trichocereus atacamensis vegetation, had been embedded within broader high-elevation units rather than recognized separately. The division of Chile’s coast into Atacama and Peruvian Sechura components remains potentially contentious because the deserts have been described as floristically very different in some studies, although the authors cite phylogenetic and floristic evidence for broader relationships and retained the wider biogeographical treatment. These examples show why international classification requires explicit decisions about boundaries and hierarchy, not just a direct one-to-one translation of national maps.

Vegetation that does not follow the climatic zonation of the landscape proved more difficult. The researchers provisionally assigned intrazonal units to 23 macrogroups, 23 divisions and 17 formations, but some correspondences are doubtful because Chile’s intrazonal categories are broad and lack sufficiently detailed descriptions. Aquatic vegetation, including floating, natant, submerged, semi-aquatic and ephemeral-wetland communities, and open-rock vegetation on coasts, cliffs, inland outcrops, landslides and caves were also considered. Moorlands in southern Chile could not be placed in a dedicated macrogroup and were associated with bog and fen categories, even though they may be more closely related to azonal wetlands. Units dominated by Nothofagus antarctica also resisted formation-level placement because the species may grow as a large shrub or small tree yet strongly determines the vegetation’s physiognomy. The researchers included these units in forest formations because accommodating them in a new macrogroup could require major changes to the international classification.

Overall, the study shows that most of Chile’s mapped zonal vegetation can be represented within the EcoVeg hierarchy, while the proposed new formations, divisions and macrogroups identify places where the international system needs adjustment. The accompanying macrogroup map is available as a shapefile, and the authors present it as a tool that can facilitate collaboration across borders. A separate effort is reportedly under review to translate Chilean phytosociological units directly into International Vegetation Classification units down to association level, potentially adding secondary, degraded and ruderal vegetation. The present results remain a cartographic and classificatory contribution: they do not demonstrate improved conservation outcomes, and the authors explicitly characterize the intrazonal assignments as preliminary. Describing and classifying those non-zonal communities remains a major pending task in Chilean vegetation science.

Subject of Research: International classification and mapping of Chilean zonal and intrazonal vegetation

Article Title: The vegetation of Chile and the EcoVeg approach in the context of the International Vegetation Classification project

Article References: Luebert, F., & Pliscoff, P. (2022). The vegetation of Chile and the EcoVeg approach in the context of the International Vegetation Classification project. Vegetation Classification and Survey, 3, 15-28. https://doi.org/10.3897/vcs.67893

Image Credits: AI Generated

DOI: 10.3897/VCS.67893

Keywords: Chilean vegetation, EcoVeg, International Vegetation Classification, vegetation mapping, biogeography, ecosystem classification, Mediterranean forests, Patagonian grasslands, Magellanian forests, conservation planning, vegetation, Chile