;"The present integrated approach";"Ecoregional approaches Bailey (1996a, 1996b), Olson et al. (2011), [Keith et al. (2020) – maps based on ecoregions]";"Eco-vegetational approaches IVC-EcoVeg (Faber-Langendoen et al. 2014, 2017, 2020)";"Ecosystem based approaches: ELUs (Sayre et al. 2015), Ecological Systems (Josse et al. 2003)" "Tentative equivalences between several types of units";"Zonobiome (macrobiome)";Biome;Formation;"Uncertain equivalences with the former, as ecological land units (ELUs) have a finer scale and are not comparable with biomes. However, several ecological systems defined for Latin America may correspond to regional or subregional biomes, and groups of related ecological systems may correspond to our biome concept." Biome;Ecoregion;Division "Regional biome";"Ecosystem functional type (EFT)";"Macrogroup or group" "Standardized nomenclatural protocol for naming units";"Systematic use of the same sequence of naming criteria and in this order: macrobioclimate, plant formation, bioclimatic level, biogeography, which apply according to the macrobiome-biome-regional biome levels.";"Heterogeneous nomenclature with no consistency or homogeneity in the GFS names assigned. Detailed principles designed for a global ecosystem typology, but lacking an objective, consistent and explicit protocol or keys to properly name the units. As the authors say: “Names of functional groups are vernacular — we adopt names and descriptors frequently applied in the literature that reflect key functional features. A vernacular (rather than systematic) approach” (Keith et al. 2020). e.g.";"Use of a similar and consistent sequence of criteria to name the units: Formation criteria: macrobioclimate-plant formation-bioclimatic level (not always applied) Division criteria: biogeography (ca. region level) Macrogroup-group criteria: Biogeography (ca. province level), Floristic composition However, biogeographical names are not standardized or somewhat ambiguous: biogeographical names mixed with purely geographic or plant names at the same hierarchical level. e.g.";"Ecological Systems use somewhat inconsistent nomenclature without a standardized protocol. ELUs cartographic unit labels follow the same more or less consistent descriptors: bioclimate, land form, lithology, Coberture." E.g.:;"D227 1. A.2.Ek Brazilian-Parana lowland humid forest:" "Step 1. Macrobiome (zonal biome): Tropical evergreen forest";"M597 Cerrado humid forest";E.g.: "T4.3 Hummock savannas";"M595 Brazilian Atlantic forest";"“Cool moist mountains on metamorphic rock with mostly deciduous forest”" "Step 2. Biome: Tropical montane evergreen forest";"T2.1 Boreal and temperate montane forests and woodlands";"D006 1. B.1.Na Southeastern North American forest & woodland:" "Step 3. Regional biome: Tropical montane Andean Yungas evergreen forest.";"T5.3 Sclerophyllous deserts and semi-deserts";"M007 Longleaf pine woodland US";"“Cold wet mountains on acidic volcanic rocks with mostly needleleaf/evergreen forest”" "T6.5 Tropical alpine meadows and shrublands";"M885 South-eastern coastal plain Evergreen oak – mixed hardwood" "Predictive capacity and repeatability";"Viable: based on numerical bioclimatic indexes and bioclimatic world maps";"Difficult to standardize and repeat, as the units and their mapping are based on expert opinion. However, the IUCN approach includes detailed descriptive definition criteria.";"Viable: based on explicit criteria to define the proposed units. However, there is some overlap and repetition of the defining criteria. Some difficulties for extrapolating outside the Americas";"Viable: based on explicit definition criteria applied with an accurate geospatial methodology for mapping detailed units." "Consistency and propriety in the use of clear descriptors and classifiers";"Consistent use of the same sequence of criteria and in the same order: macrobioclimate, plant formation, bioclimatic belt, biogeography, which apply according to the macrobiome-biome-regional biome levels.";"Ecofunctional explicit approach Key assembly gradients: water deficit, seasonality, temperature, nutrient deficiency, fire activity and herbivory.";"Use of a similar and consistent sequence of criteria:";"ELUs use the same criteria applied to design mapping units." "Formation: macrobioclimate-plant formation-bioclimatic level (not always applied)";"Input layers: elevation, landforms, geology, bioclimate, land cover." "(Keith et al. 2020)";"Division: biogeography (ca. region level)";"Structural consideration of ecosystems:" "Mixing and overlapping of the descriptors and classifiers used:";"Macrogroup-group: Biogeography (ca. province level), Floristic composition";"“Ecosystems can therefore be spatially delineated by mapping and integrating these structural components in geographic space” (Sayre et al. 2015)." "some overlaps between the vegetation structure and the bioclimate: e.g., is “humid” a vegetation term or a climate term? Do the terms “desert” and “semi-desert” refer to the physiognomy of the vegetation? or the climate? or both?";"Somewhat inconsistently applied names for descriptors and nomenclature." e.g. "Structural consideration of biomes";"Mixed forest" "Hardwood forest & woodland" "Proper definition of the concepts used related to plant formation names";"Clear and consistently applied plant formation concepts, based on the same sequence of growth forms and phenological leaf persistency.";"Glossary definition of several terms used in the EFG descriptions. The terminology of plant formations is not standardized or well-defined and delimited. Some examples:";"Based on dominant plant growth forms.";"Global ELUs use the following land cover classes and class mosaics:" "Repeatable terminology for growth forms and foliage persistency, largely based on Ellenberg & Mueller-Dombois (1967), Rivas-Martínez (2005) and EcoVeg (2014).";"- What is the difference and clear delimitation between steppes, grasslands and savannas?";"Detailed descriptions of plant growth forms, however, plant formation names remain non-standardized.";"bare areas, artificial surfaces and urban areas, shrubland, closed to open, broadleaved or needle-leaved, evergreen or deciduous, herbaceous vegetation, closed to open, grassland, savannas or lichens/mosses" "The criterion of leaf phenology is easier to apply consistently than the commonly applied terms of humidity, which alternate or superimpose “climate humidity” with “vegetation humidity”: the denomination “evergreen” is preferable to “humid” and “rainforest”, as evergreen implies a pluvial bioclimate.";"- Some relevant Neotropical formations are not represented, e.g., the extensive woodlands and wooded or arboreal savannas of the Cerrado biome in South America (Brazil, Bolivia, Paraguay).";"e.g. Overlap between the vegetation structure and the bioclimate: Is “humid” a vegetation or a climatic term?";"mosaic forest or shrubland with grassland mosaic grassland with forest or shrubland mosaic vegetation (grassland/shrubland/forest) with cropland" "- There is no climatic qualifier for savannas, but the proper concept of savanna is only tropical.";"South American ELUs are based on LAC NatureServe denominations of ecological systems with somewhat poorly defined and delimited or inconsistently applied plant formation names." "- Inappropriate use of the term “alpine” for tropical high-montane grasslands." "Proper definition of the concepts used related to bioclimates";"Based on the World Bioclimatic System (Rivas-Martínez et al. 2011) that defines with numerical indexes: thermotype, ombrotype, bioclimate, bioclimatic levels.";"Tropical, Subtropical, Temperate, Cool temperate, Boreal, Polar, Lowland, Montane, High-montane: there is no clear delimitation and conceptual definition for these terms, and they do not explicitly follow any bioclimatic system.";"Somewhat poorly defined and delimited or confusingly applied climatic categories";"Ecological System partially uses the World Bioclimatic System of Rivas-Martínez (only ombrotypes). Global ELUs use simplified climate categories:" e.g.;Arctic "Dry/Seasonal dry";"Very Cold Very Wet" Temperate/Mediterranean;"Very Cold Wet" Semi-desert/Hyperdesert;"Very Cold Moist" "Terms are not consistently applied in all EFGs: e.g. only “cool” deserts?";"Cool/warm desert";"Very Cold Semi-Dry" "Very Cold Dry" "Very Cold Very Dry" "The Mediterranean bioclimate is subsumed or immersed in the Temperate bioclimate which introduces uncertainty in several EFGs";"South American ELUs use global meteorological raster data and formulas developed by the Rivas-Martinez bioclimatic system to delineate isobioclimate regions" "Dynamic-successional character of the vegetation";"Successional approach: we postulate that biome is defined by the natural potential vegetation, and that the successional states are considered (at these scales) to be included in the potential natural vegetation.";"Actualistic approaches: successional states are not considered to be immersed in the potential vegetation, but rather constitute different units:" "e.g. (EcoVeg and Ecological Systems: “M515 Caribbean-Mesoamerican Lowland Ruderal Grassland &" "Shrubland”; “M123 Eastern North American Ruderal Grassland & Shrubland”; “M310 Southeastern North American Ruderal Flooded & Swamp Forest”." "IUCN (Keith et al. 2020) “T7: Intensive Land Use Biome” are roughly equivalent to anthromes." "Dynamic-successional character of the vegetation";"However, in highly transformed landscapes, when the dominant landscape matrix is extensively disturbed ecosystems, we still consider them as anthromes (anthro-biomes) (Ellis 2020).";"Not explicit" "Ecological landscape framework to address biomes or units";"We introduce a geographic-ecological framework to qualify biomes, through the concept of geoseries (geocatena, geosigmetum) that is applicable to regional biomes and biomes.";"Not explicit";"Not explicit";"Not explicit Ecological Systems: “spatially co-occurring assemblages of vegetation types sharing a common underlying substrate, ecological process or gradient” (Josse et al. 2003)" "Ecological or bioclimatic levels";"We consider the altitudinal zonation as a characteristic of each biome, and one that serves to delimit it. Altitudinal levels are in accordance with the thermicity index values of Rivas-Martínez et al. (2011). We performed an operational simplification of the detailed Rivas-Martínez bioclimatic levels, based on Josse et al. (2009), in order to make them easier to apply at the biome scale.";"Altitudinal belts are underrepresented (only lowland/montane), and their delimitation criteria are not explicit.";"There is no standardized use of the nomenclature of the elevation; the delimitation criteria are not explicit. Altitudinal levels are more detailed in South American units (lowland, low-montane, montane, upper montane, high-montane) than in North American units (lowland, lower montane, montane, high montane, subalpine). The criteria delimiting altitudinal levels are not explicit.";"They accept elevation classes based on published literature for South American ecosystems: 0–500 m, 500–1000 m, 1000–2000 m, 2000–3300 m, and > 3300 m" "Eco-functional approach";"We stated that a bioclimate-based structural approach is ecofunctional in nature since the limiting climate variables condition and determine the appearance and structural adaptations of the vegetation, and the soil complexes on which it develops, thus behaving as ecosystem drivers.";"Ecofunctional explicit approach. However, several IUCN ecofunctional drivers, key assembly gradients or properties described in the EFGs can be derived consistently from the respective bioclimates, in a more parsimonious way: at least water deficit, temperature and thermal seasonality in a direct way, and indirectly, nutrient deficiency, fire activity and herbivory.";"Not explicit"