The Cenozoic vegetation of the Iberian Peninsula: A synthesis

The aim of this work is to provide a first approach to the evolution of Iberia's vegetation during the Cenozoic (with the exclusion of the Quaternary). The Palaeogene was floristically defined by Palaeotropical elements forming tropical/subtropical rainforests, mangrove swamps, edaphically-mediated laurophyllous forests and leguminous-sclerophyllous communities. During the Miocene, Iberian landscapes were drastically modified due to geographic and climatic changes (mainly cooling and aridification) changes. Open, steppe-like environments developed towards the interior of the peninsula and Arctotertiary elements invaded mountainous and riparian ecosystems, coexisting with or becoming part of evergreen, broadleaved forests of Palaeotropical species. From the Late Miocene onwards these forests suffered changes due to the extinction of taxa, the impact of environmental change on the survivors, and the perturbations caused by the arrival of further Arctotertiary elements. However, several Palaeotropical taxa overcame the environmental and climatic changes of the Miocene and Pliocene to form a part of the modern flora of the Iberian Peninsula.     

Patterns of extinction and persistence of Arctotertiary flora in Iberia during the Quaternary

The native or allochthonous nature of certain extant species of the Iberian Peninsula is a matter of some controversy given our lack of knowledge regarding the survival and extinction processes to which they have been subject. The aim of the present work is to provide a review of the current knowledge regarding these processes during the Quaternary. The Middle Pleistocene Transition was a period of noticeable disappearance of Arctotertiary taxa in the Iberian Peninsula, related to the alteration in glacial cyclicity and climate change, including an increase in the severity of glaciations, a reduction in the length of the interglacial periods, and increased dryness during the coldest times. It is difficult to maintain that human activities played any important part in the complete or near-complete disappearance of some taxa during the Quaternary. In the Late Pleistocene and Holocene, however, the extinction of Cedrus, Picea and Carpinus might be related to climate change, competition with other taxa, and anthropogenic disturbances. In contrast, the extreme reduction or even complete disappearance of Platanus or Syringa seems to be due to natural causes alone. The available geological, molecular and palaeobotanical data suggest that some Arctotertiary taxa persisted over long periods of time during the Quaternary in the Iberian Peninsula. Indeed, the fossil record of one important group of taxa, including Castanea, Ceratonia, Carpinus and Juglans, shows its continued presence throughout the Quaternary.     

A Quaternary perspective on the conservation prospects of the Tertiary relict tree Prunus lusitanica L.

Aim  To assess the importance of climate and human pressure as factors limiting the past, present and future distribution of Prunus lusitanica L. (the Portuguese laurel), a relict of Europe's ancient subtropical laurel-forest flora.
Location  The Iberian Peninsula.
Methods  A census was taken of the current populations of P. lusitanica in the Iberian Peninsula and the threats they face. The potential distribution of the species was modelled under current climatic conditions and under simulations of the climate for the Last Glacial Maximum (LGM), the mid-Holocene and the year 2080.
Results  The present total population of 31,000 individuals is largely distributed as small, fragmented subpopulations, often threatened by agriculture or forestry. The species' current range is much smaller than its potentially suitable range. During the LGM, P. lusitanica would have been constrained to a limited number of sites along the Atlantic coast. In the mid-Holocene, its potential range was much wider than during the LGM and similar to that of the present day. Under the 2080 climate scenario its potential range is reduced by almost 40% compared to that of the present. This reduction includes the loss of territories currently home to three-quarters of its Iberian population.
Main conclusions  Drastic climatic changes and the existence of refugia are usually invoked to explain the rarity and fragmented distribution – yet persistence – of a subtropical flora in southern Europe. The availability of climatically suitable habitats is, however, not necessarily the main factor limiting its distribution. Human impact would appear to have been – and continues to be – of fundamental importance in the current population sizes and potential range of P. lusitanica in the Iberian Peninsula.     

Steppes, savannahs, forests and phytodiversity reservoirs during the Pleistocene in the Iberian Peninsula

A palaeobotanical analysis of the Pleistocene floras and vegetation in the Iberian Peninsula shows the existence of patched landscapes with Pinus woodlands, deciduous and mixed forests, parklands (savannah-like), shrublands, steppes and grasslands. Extinctions of Arctotertiary woody taxa are recorded during the Early and Middle Pleistocene, but glacial refugia facilitated the survival of a number of temperate, Mediterranean and Ibero-North African woody angiosperms. The responses of Iberian vegetation to climatic changes during the Pleistocene have been spatially and temporarily complex, including rapid changes of vegetation in parallel to orbital and suborbital variability, and situations of multi-centennial resilience or accommodation to climatic changes. Regional characteristics emerged as soon as for the Middle Pleistocene, if not earlier: Ericaceae in the Atlantic coast indicating wetter climate, thermo-mediterranean elements in the south as currently, and broad-leaf trees in the northeastern. Overall, steppe landscapes and open Pinus woodlands prevailed over many continental regions during the cold spells of the Late Pleistocene. The maintenance of a high phytodiversity during the glacials was linked to several refuge zones in the coastal shelves of the Mediterranean and intramountainous valleys. Northern Iberia, especially on coastal areas, was also patched with populations of tree species, and this is not only documented by palaeobotanical data (pollen and charcoal) but also postulated by phylogeographical models.     

Composition, geographical affinities and endemism of the Iberian Peninsula orchid flora

The orchid flora of the Iberian Peninsula is relatively well known, but its biogeographical and diversity patterns have until now remained unanalysed. This work compares the richness of this flora with that of 27 other territories in different continents and at different latitudes, with the aim of establishing whether it is richer or poorer than might be expected. Latitude was found to be an excellent predictor of regional orchid species richness. With 122 taxa, the orchid flora of the Iberian Peninsula is more or less as diverse as that of other Mediterranean areas of similar latitude (e.g. France, Greece or Italy), but more diverse than other European or indeed North African orchid floras. In this study, the Iberian orchid species were assigned to eight monophyletic clades and the global distribution of these are mapped to establish continental affinities between the floras. A recent floristic account on the Iberian orchids was also used to assign the orchid taxa to habitats, and the relationship between the number of endemisms and their habitats was analysed. The patterns of endemism differed in different habitats. Very high levels of endemism were found in habitats peculiar to the Mediterranean Basin, indicating the relict status of its orchid flora.     

Refugia within refugia – patterns in endemism and genetic divergence are linked to Late Quaternary climate stability in the Iberian Peninsula

In Europe, southern peninsulas served as major refugia during Pleistocene cold periods. However, growing evidence has revealed complex patterns of glacial survival within these southern regions, with multiple glacial refugia within each larger refugial area. We investigated the extent to which patterns of endemism and phylogeographic are concordant across animal species in the Iberian Peninsula, one of the most important unglaciated areas in Europe during the Pleistocene, can be explained in terms of climatic stability. We found that historical climatic stability (notably climate velocity measures integrating macroclimatic shifts with local spatial topoclimate gradients) was often among the most important predictors of endemic species richness for different taxonomic groups using models that also incorporated measures of modern climate. Furthermore, for some taxonomic groups, climatic stability was also correlated with patterns of spatial concordance in interpopulation genetic divergence across multiple taxa, and private haplotypes were more frequently found in relatively stable areas. Overall, our results suggest that both endemism patterns and cross‐taxa concordant phylogeographic patterns across the Iberian Peninsula to some extent are linked to spatial variation in Late Quaternary climate stability, in agreement with the proposed ‘refugia‐within‐refugia’ scenario. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 13–28.     

Ecological differentiation and cladogenesis of Baldellia (L.) Parl. (Alismataceae)

The Iberian Peninsula is home to a large number of endemic species that often show strong genetic subdivisions which indicate possible isolation of populations in the past. Numerous phylogeographic and phylogenetic studies on Iberian flora and fauna have revealed this territory to be the origin of genetic differentiation during the Pleistocene Ice Age. To better understand the influence of Plio-Pleistocene climatic oscillations on the cladogenesis and population structuring of refugial taxa restricted to freshwaters of the Iberian Peninsula, we studied the evolutionary history of the small European genus Baldellia, both from a phylogenetic/phylogeographic perspective and regarding its ecological characteristics. Molecular analyses were based on four plastid regions and nuclear ITS2 ribosomal spacer from individuals belonging to geographically isolated Baldellia populations, while the relationships between climate and Baldellia species distribution was investigated by redundancy analysis applied to the climatic data with the occurrence of Baldellia species as external variables. The absence of a clear phylogenetic signal most likely reflects a common and recent cladogenesis for Baldellia. In contrast, the more rapidly evolving plastid sequences indicate a recent phylogeographic history of refugial repartition and ecological segregation probably occurring during the last glaciation, a scenario well supported by marked differences in species?? ecological preferences and climate analysis.     

华南地区新生代木乃伊化木化石研究进展*

中国木化石资源虽然很丰富, 但研究程度相比叶片化石要低得多, 且主要集中在中国北部和西南地区, 研究领域大多局限于分类学方面, 而木化石分析与古气候、古生态等领域的交叉和系统研究还很少。大多数情况下木化石的保存方式都为石化或矿化保存, 而木乃伊化保存的木化石则非常罕见。木乃伊化保存的化石在植物分类、系统演化及古气候研究等方面具有独特而重要的价值。近年来, 本团队在华南地区发现大量木乃伊化保存的新生代木化石, 它们分别产自广西南宁盆地晚渐新世邕宁组、广西桂平盆地中新世二子塘组以及广东茂名盆地晚更新世地层中。本文总结了这些木乃伊化保存的木化石的研究进展, 包括多样性组成、古植被、古气候及古生态等特征, 并对木兰属、蒲桃属和枫香属的植物地理史进行了讨论。综合分析植物群组成特征和木材生长轮以及木化石中具有气候指示意义的解剖结构特征, 推测广西南宁盆地晚渐新世时期生长着常绿(少数落叶)阔叶林, 为温暖湿润的亚热带季节性气候; 广西桂平盆地中新世时期生长着常绿—落叶、阔叶—针叶混交林 (阔叶为主), 为温暖湿润的亚热带气候; 广东茂名盆地晚更新世生长着常绿—落叶、阔叶—针叶混交林, 为温暖湿润的亚热带至热带季风气候。这是中国低纬度地区首次系统研究木乃伊化保存的木化石, 为新生代植物群的系统演化和古环境分析等提供了重要的木化石依据。     

Survival and long-term maintenance of tertiary trees in the Iberian Peninsula during the Pleistocene: first record of Aesculus L. (Hippocastanaceae) in Spain

The Italian and Balkan peninsulas have been places traditionally highlighted as Pleistocene glacial refuges. The Iberian Peninsula, however, has been a focus of controversy between geobotanists and palaeobotanists as a result of its exclusion from this category on different occasions. In the current paper, we synthesise geological, molecular, palaeobotanical and geobotanical data that show the importance of the Iberian Peninsula in the Western Mediterranean as a refugium area. The presence of Aesculus aff. hippocastanum L. at the Iberian site at Cal Guardiola (Tarrasa, Barcelona, NE Spain) in the Lower–Middle Pleistocene transition helps to consolidate the remarkable role of the Iberian Peninsula in the survival of tertiary species during the Pleistocene. The palaeodistribution of the genus in Europe highlights a model of area abandonment for a widely-distributed species in the Miocene and Pliocene, leading to a diminished and fragmentary presence in the Pleistocene and Holocene on the southern Mediterranean peninsulas. Aesculus fossils are not uncommon within the series of Tertiary taxa. Many appear in the Pliocene and suffer a radical impoverishment in the Lower–Middle Pleistocene transition. Nonetheless some of these tertiary taxa persisted throughout the Pleistocene and Holocene up to the present in the Iberian Peninsula. Locating these refuge areas on the Peninsula is not an easy task, although areas characterised by a sustained level of humidity must have played an predominant role.     

New costapalmate palm leaves from the Oligocene Ningming Formation of Guangxi,China, and their biogeographic and palaeoclimatic implications

New palm leaves from the Oligocene Ningming Formation are placed into the morphogenus Sabalites because of their costapalmate leaf shape. Four taxa are described on the basis of leaf compressions with cuticular structure. S. guanxiensis sp. nov. is characterised by hypostomatic leaf blades with a stout costa and a symmetrical base. Sabalites cf. asymmetricus has amphistomatic leaf blades with a long, delicate costa and an asymmetrical base. Sabalites sp. 1 has amphistomatic leaf blades with a long, massive costa and wide segments. Sabalites sp. 2 is characterized by hypostomatic leaf blades with a prominent costa and an asymmetrical base. The four new palm taxa expand our understanding of the floristic elements and features of the Oligocene Ningming flora. Together with the other three palm taxa that were previously reported from the Ningming Formation, our material indicates that the Oligocene Ningming flora had a rich diversity of costapalmate palms. The relatively high species diversity of palms and other plants corroborate that the Oligocene Ningming flora represents a warm and humid climate.     

Conservatism of ecological niche characteristics in North American plant species over the Pleistocene-to-Recent transition

Aim  To provide a test of the conservatism of a species' niche over the last 20,000 years by tracking the distribution of eight pollen taxa relative to climate type as they migrated across eastern North America following the Last Glacial Maximum (LGM).
Location  North America.
Methods  We drew taxon occurrence data from the North American pollen records in the Global Pollen Database, representing eight pollen types – all taxa for which ≥5 distinct geographic occurrences were available in both the present day and at the LGM (21,000 years ago ± 3000 years). These data were incorporated into ecological niche models based on present-day and LGM climatological summaries available from the Palaeoclimate Modelling Intercomparison Project to produce predicted potential geographic distributions for each species at present and at the LGM. The output for each time period was projected onto the 'other' time period, and tested using independent known occurrence information from that period.
Results  The result of our analyses was that all species tested showed general conservatism in ecological characteristics over the climate changes associated with the Pleistocene-to-Recent transition.
Main conclusions  This analysis constitutes a further demonstration of general and pervasive conservatism in ecological niche characteristics over moderate periods of time despite profound changes in climate and environmental conditions. As such, our results reinforce the application of ecological niche modelling techniques to the reconstruction of Pleistocene biodiversity distribution patterns, and to project the future potential distribution range of species in the face of global-scale climatic changes.     

Mammalian niche conservation through deep time

Climate change alters species distributions, causing plants and animals to move north or to higher elevations with current warming. Bioclimatic models predict species distributions based on extant realized niches and assume niche conservation. Here, we evaluate if proxies for niches (i.e., range areas) are conserved at the family level through deep time, from the Eocene to the Pleistocene. We analyze the occurrence of all mammalian families in the continental USA, calculating range area, percent range area occupied, range area rank, and range polygon centroids during each epoch. Percent range area occupied significantly increases from the Oligocene to the Miocene and again from the Pliocene to the Pleistocene; however, mammalian families maintain statistical concordance between rank orders across time. Families with greater taxonomic diversity occupy a greater percent of available range area during each epoch and net changes in taxonomic diversity are significantly positively related to changes in percent range area occupied from the Eocene to the Pleistocene. Furthermore, gains and losses in generic and species diversity are remarkably consistent with ~2.3 species gained per generic increase. Centroids demonstrate southeastern shifts from the Eocene through the Pleistocene that may correspond to major environmental events and/or climate changes during the Cenozoic. These results demonstrate range conservation at the family level and support the idea that niche conservation at higher taxonomic levels operates over deep time and may be controlled by life history traits. Furthermore, families containing megafauna and/or terminal Pleistocene extinction victims do not incur significantly greater declines in range area rank than families containing only smaller taxa and/or only survivors, from the Pliocene to Pleistocene. Collectively, these data evince the resilience of families to climate and/or environmental change in deep time, the absence of terminal Pleistocene "extinction prone" families, and provide valuable insights to understanding mammalian responses to current climate change.     

Paleobiogeography of an Iberian endemic species,Luciobarbus sclateri (Günther, 1868) (Actinopterygii,Cyprinidae), inferred from mitochondrial and nuclear markers

Since the Cenozoic Era, the southern Iberian Peninsula has undergone a series of complex geological and climatic changes that have shaped the hydrographic configuration of the freshwater network, influencing the present‐day distribution of primary freshwater species and favoring a high level of local endemicity. The cyprinid species Luciobarbus sclateri (Günther, 1968) is an endemic species confined to the southern Iberian Peninsula and characterized by a complex evolutionary history. Previous studies linked the structure of L. sclateri populations to the effects of climate change during glaciations and were not able to explain the genetic discordance found between nuclear and mitochondrial markers. The results of this study show that the structure of L. sclateri populations is a reflection of diversification processes linked to the geological history of the region. Thus, we found three main mitochondrial phylogroups: the first one corresponding to small basins in southern Iberian Peninsula, a second one in eastern Iberian Peninsula, corresponding to Segura population, and a third one including the rest of the basins where the species is distributed. The southern group began diverging in the Pliocene as result of tectonic dynamics characterized by the emersion of the basins around the Strait of Gibraltar. The other two groups began diverging with the formation of the current Iberian hydrographic system during Pleistocene. So, the isolation of the hydrographic basins was the main factor driving intraspecific differentiation, followed by recent secondary contacts, admixture, and re‐isolation of the populations.     

A biogeographical analysis of the European Atlantic lowland heathlands

Questions: What is the climatic envelope of European Atlantic heathlands and the relationship between their floristic geographical variability and climatic parameters? Are the biogeographic patterns extracted from genuine heath plants comparable to those extracted from the accompanying flora? To what extent does the species composition extracted from phytosociological data support the current theory of refuge areas of heath vegetation in southern Atlantic Europe during the Pleistocene ice ages? Location: Atlantic Europe and NW Morocco. Methods: The geographical territory in which Atlantic heathlands occur was divided into 23 sectors following geographic and chorological criteria. A presence–absence table with 333 taxa was then constructed with the available phytosociological data. The taxa were classified into different groups according to their phytosociological affinity. Several types of numerical analysis were performed with this matrix and the climatic data obtained from meteorological sources. Results: Heathlands require a humid and oceanic climate and are limited by cold temperatures in the north and by summer droughts in the south. The highest floristic richness of this vegetation type is found in NW Iberia. Ordinations indicate a strong correlation between floristic composition of biogeographic sector and summer drought (Ios) and thermicity (It). Conclusions: The main climatic factors determining lowland heathland floristic distribution are thermicity and summer drought. The current optimal conditions for heath flora in NW Iberia suggest that there were southern refuges during the Pleistocene ice ages from which northward expansion has taken place.     

Miocene to Pliocene vegetation reconstruction and climate estimates in the Iberian Peninsula from pollen data

Pollen analysis of Miocene and Pliocene sediments from the Iberian Peninsula shows a progressive reduction in plant diversity through time caused by the disappearance of thermophilous and high-water requirement plants. In addition, an increase in warm-temperate (mesothermic), seasonal-adapted “Mediterranean” taxa, high-elevation conifers and herbs (mainly Artemisia) occurred during the Middle and Late Miocene and Pliocene. This has mainly been interpreted as a response of the vegetation to global and regional processes, including climate cooling related to the development of the East Antarctic Ice Sheet and then the onset of the Arctic Ice Sheet, uplift of regional mountains related to the Alpine uplift and the progressive movement of Eurasia towards northern latitudes as a result of the northwards subduction of Africa. The development of steppe-like vegetation in southern Iberia is ancient and probably started during the Oligocene. The onset of a contrasted seasonality in temperature during the Mid-Pliocene superimposed on the pre-existing seasonality in precipitation, the annual length of which increased southward. The Mediterranean climatic rhythm (summer drought) began about 3.4 Ma and caused the individualization of modern Mediterranean ecosystems. Quaternary-type Mediterranean climatic fluctuations started at 2.6 Ma (Gelasian) resulting in repeated steppe vs. forest alternations. A latitudinal climatic gradient between the southern and the northern parts of the Iberian Peninsula existed since the Middle Miocene.     

Ethnobotanical Resources Management in the Arribes del Duero Natural Park (Central Western Iberian Peninsula): Relationships between Plant Use and Plant Diversity, Ecological Analysis, and Conservation

We analyze the floristic and ecological diversity of plants traditionally used in the Arribes del Duero Natural Park (Central Western Spain, Iberian Peninsula). We identified all plant species used by the local people and classified them in 10 general use-categories. All the ethnobotanical data used derive from global ethnobotanical research carried out from 2005 to 2009. The results are analyzed with respect to the total flora of the area and to the ecological diversity of the species in their habitats. The conservation and management of these taxa are also analyzed. We discuss the implications of their harvesting for the development and conservation of their natural populations and habitats.     

Early stages of formation and dispersal of the temperate flora in the Boreal Region

Budantsev, L. Yu. (Komarov Botanical Institute, Prof. Popov Str. 2, 197376 St. Petersburg, Russia). Early stages of formation and dispersal of the temperate flora in the Boreal Region. Bot. Rev.58(1): 1–48, 1992.—The thesis of this review is that, as stated as early as 1908 by V. L. Komarov, the composition of a flora can be understood only as a process, or separate stage, in the context of migration in time and space of various floristic assemblages and their isolation, as induced by transformation of continental and ocean shapes, changes in climate, and the environment as a whole. Thus the formation of geofloras of the past was influenced by gradually changing environments that determined the spread, patterning, and spatial differentiation of floras and their evolution. Parallel to the more commonly-seen names of eras—Paleozoic, Mesozoic, and Cenozoic—we can speak of the Paleophytic, Mesophytic, and Cenophytic eras. Eras defined in these two ways (by faunistic or by floristic criteria) do not completely coincide. Generally, changes in the flora have, necessarily, preceded changes in the fauna. It is the Cenophytic with which this review is mostly concerned, the era of Angiosperm dominance. The movement of early subtropical and warm temperate floras in the Early Cenophytic, followed by temperate or even boreal floras, as the climate changes, is traced in detail. The regions discussed most fully are the Boreal-Atlantic and Boreal-Pacific, with emphasis on the Angaro-Beringian flora. The disappearance of archaic forms (e.g., cycadophytes) and the gradual predominance of angiosperms is documented. The movements of the floral assemblages in response to environmental changes are mapped and described. The early development and diversification of the boreal temperate flora is considered to have taken place mainly in Angaro-Beringia, associated with the invasive migration of tropical angiosperms from southeastern Asia.     

Bryophyte flora of the Sierras de Filabres,Cabrera, Alhamilla and Cabo de Gata (Almería,S.E. Spain)

Abstract

The bryophyte flora of the Sierras de Filabres, Cabrera, Alhamilla and Cabo de Gata of Almería province (S.E. Spain) includes 280 taxa (236 mosses and 44 liverworts) of which 74 are new to the province of Almería, 31 to the southeastern part of the Iberian Peninsula and 4 to the Iberian Peninsula. Data about their biogeography and ecology are given.     

Complex patterns of environmental niche evolution in Iberian columbines (genus Aquilegia,Ranunculaceae)

Aims This study explores the patterns of niche differentiation in a group of seven closely related columbines (genus Aquilegia, Ranunculaceae) from the Iberian Peninsula. Populations of these columbines are subject to complex patterns of divergent selection across environments, which partly explain the taxonomic structure of the group. This suggests the hypothesis that niche divergence must have occurred along the process of diversification of the group.Methods We used MaxEnt to build environmental niche models of seven subspecies belonging to the three species of Aquilegia present in the Iberian Peninsula. From these models, we compared the environmental niches through two different approaches: ENMtools and multivariate methods.Important findings MaxEnt distributions conformed closely to the actual distribution of the study taxa. ENMtools methods failed to uncover any clear patterns of niche differentiation or conservatism in Iberian columbines. Multivariate analyses indicate the existence of differentiation along altitudinal gradients and along a gradient of climatic conditions determined by the summer precipitation and temperatures. However, climatic conditions related to winter temperature and precipitation, as well as soil properties, were equally likely to show conservatism or divergence. The complex patterns of niche evolution we found suggest that Iberian Columbines have not been significantly constrained by forces of niche conservatism, so they could respond adaptively to the fast and profound climate changes in the Iberian Peninsula through the glacial cycles of the Pleistocene.     

How general are global trends in biotic homogenization? Floristic tracking in Chile,South America

Aim   To quantify the occurrence of floristic change in the vascular flora of Chile. We test whether continental areas have experienced floristic modification leading to either homogenization, differentiation or tracking.
Location   Continental Chile.
Methods   On the basis of the geographical distribution of native (1806 species) and naturalized plants (552 species) in continental Chile, we quantified change between two floristic stages: (1) pre-European flora, including native extant and extinct species; and (2) current flora, including native and naturalized species, but excluding extinct plants. We compared changes in compositional similarity (calculated by Jaccard's index, Δ J ) between pairs of regions, and similarity decay with respect to geographical distance. Additionally, by means of Whittaker's index, we examined species turnover, distinguishing between native and naturalized plants.
Results   Between floristic stages (pre-European vs. current flora) no significant changes in floristic similarity were noted at national or regional scales. Similarity decay showed no statistical differences between pre-European and current flora. Analysing patterns of geographical turnover, we found that species turnover of naturalized plants over their geographical range is similar to that of native plants.
Conclusions   The composition of the continental flora of Chile does not show significant modifications in similarity patterns after considering naturalized species, thus indicating floristic tracking. The causes of this phenomenon may be related to the current geographical distribution of naturalized plants, which closely parallels that of native plants. Our results differ from those obtained in Northern Hemisphere continents, thus indicating that trends of biotic change may differ between hemispheres.