Checklist and red list of hornworts (Anthocerotophyta) and liverworts (Marchantiophyta) of Slovakia

The presented checklist and red list include 231 liverwort (Marchantiophyta) and two hornwort species (Anthocerotophyta). Overall, 22.9% of liverworts are evaluated as threatened (CR – 4.3%, EN – 7.8%, VU – 10.8%), while 17 of species (7.4%) are categorized as NT, 11.6% as DD and 3.0% as RE. A total of 128 species (55.4% of the liverwort flora of Slovakia) were assessed as LC. For the liverwort Lunularia cruciata the criteria were not applicable (NA), since this species is not native to Slovakia. Currently, only two hornworts are known in Slovakia, of which Anthoceros agrestis is assessed as LC and Phaeoceros carolinianus as NT. The main factors of the liverwort and hornwort endangerment and retreat are anthropogenic changes in natural conditions and degradation of the ecosystems caused by agriculture, forestry, aquaculture, climatic changes, industry, and traffic pollution.


Introduction
Up to date, three editions of the Checklist of liverworts and hornworts (Kubinská et al. 1993;Janovicová 1996, 1998) and two of their updated editions (Kubinská et al. 2001a, b) including the Red list of bryophytes evaluated according to the IUCN criteria (IUCN 2001) have been published in Slovakia. Since then, several species new to Slovakia have been recorded. The revised checklist and red list of hornworts (Anthocerotophyta) and liverworts (Marchantiophyta) follow the latest version of the Checklist of mosses (Bryophyta) (Mišíková et al. 2020). Based on current knowledge, occurrence and threat status of hornworts and liverworts are less processed compared to mosses. At present, data from most areas of Slovakia are absent or are only partially known with the exception of the Tatra Mountains, where distribution, chorology and the population numbers of some species are well documented (Šoltés 1990, 2002Górski and Váňa 2014;Górski 2016Górski , 2020. The aim of this work is to present the current state of endangerment and nomenclatural changes of liverworts and hornworts of Slovakia.

Methods
All hornwort and liverwort species that have been recorded in Slovakia up to the end of February 2020 were taken into consideration. The updated checklist and red list are based on previous lists (Kubinská et al. 2001a, b) and are treated according to recently published results. Nomenclature of taxa follows the European checklist of bryophytes (Hodgetts et al. 2020), except Lophocolea coadunata. As the dioicous species Lophocolea coadunata was not distinguished from the autoicous Lophocolea bidentata in Slovakia, we do not treat these species separately. Accepted names are cited in bold. Species varieties are listed by generally distinguished taxa.

Red list
The presented edition of the red list follows the IUCN Species Survival Commission Guidelines (2012) considering the guidelines for bryophytes (Hallingbäck 2006;Hodgetts et al. 2019). Recommendations provided by Bergamini et al. (2019) were used to define the concept of an adult individual. According to the IUCN (2012), the IUCN Standards and Petitions Subcommittee (2019), Hodgetts et al. (2019) and Mišíková et al. (2020), eight categories were used.
1. Regionally extinct (RE): A species is Regionally Extinct when it is extinct or not confirmed since 1970 within the region assessed (Slovakia), but populations can still be found in areas outside the region. A small chance remains that such species may still persist and be rediscovered.

Critically endangered (CR): A species is Critically
Endangered when it meets the criteria for this category, indicating that the species is facing an extremely high risk of extinction. 3. Endangered (EN): A species is Endangered when it meets criteria for endangered with a very high risk of extinction in the region. 4. Vulnerable (VU): A species is Vulnerable when it meets the criteria for this category, indicating that the species is facing a high risk of extinction in the region.

Near threatened (NT): A species is Near Threatened when
it does not meet the criteria for CR, EN or VU, but may likely become at risk of extinction in the near future. 6. Least concern (LC): A taxon is considered to be of Least Concern if it does not qualify for CR, EN, VU or NT. Species classified as Least Concern are considered at low risk of extinction. Widespread and abundant species are typically classified in this category. 7. Data deficient (DD): Includes taxa for which the lack of data does not allow an assesment of its risk of extinction. Listing of taxa in this category indicates that more information is required and acknowledges the possibility that future research will show that threatened classification is appropriate. 8. Not applicable (NA): This category includes species occurring outside their natural range, which cannot be evaluated on the basis of the selected criteria.
Due to lack of appropriate information for species classification into threat categories, only IUCN criterion B (subcriteria B1 and B2), C (subcriteria C1 and C2) and criterion D (subcriterion D2) ( Table 1) were taken into account in the evaluation process.
Only one record of this species is known from Slovakia by now (Loskotová 2006). It is highly probable it grows on several localities where it is not distinguished from Aneura pinguis. According to Hodgetts et al. (2020) the species is at present lacking a valid name, Aneura maxima is a SE Asian taxon which is not conspecific with the European taxon. (dioicous) as separate species. As these two species were not distinguished in Slovakia in the past (herbarium documents of literary data are often missing or herbarium items are sterile), we do not treat them separately. Lophocolea bidentata probably prefers more acidic and nutrient-poor habitats, while L. coadunata often grows in human-influenced habitats (lawns, gardens, parks) (Köckinger 2017).

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Lophozia guttulata, Lophozia longiflora. As mentioned by Hodgetts et al. (2020), Lophozia guttulata was included in Lophozia longiflora, until Bakalin (2016) lectotypified L. longiflora. Available herbarium and literary records from Slovakia concern only the species L. guttulata, however, L. longiflora could probably also occur in our territory. Köckinger (2017) and Hodgetts et al. (2020) report this species as typical for acidic, peaty soil and rocks, while L. guttulata grows mostly on dead wood in moist habitats. The main morphological differences between L. longiflora and L. guttulata are in perianth armature, leaves length and width ratio and leaf shape (Bakalin 2016).  (2017), Klama and Górski (2018) and Hodgetts et al. (2020) we present both species separately. M. collaris grows mainly on alkaline rocks and it is relatively widespread on limestones of Slovak mountains. M. bantriensis occurs in wet habitats, springs, wetlands and also on wet rocks, e.g. at stream banks, similar to M. collaris. As not all herbarium items have been revised and some of them are unavailable for several literature data, real distribution and endangerment of M. bantriensis need to be updated.  Duda andVáňa 1970, 1971;Górski and Váňa 2014) both are listed as separate species.

Redlist
Overall, 231 liverwort species and two hornworts were evaluated (Table 2). A total of 128 species (55.4% of the liverwort flora of Slovakia) were assessed as LC, while 10 species (4.3%) were categorized as CR, 18 (7.8%) as EN and 25 (10.8%) as VU, which represent 22.9% of the flora. A total of 17 species (7.4%) were categorized as NT and 27 species (11.6%) are data deficient (DD). Only for the liverwort Lunularia cruciata the criteria were not applicable since this species is not native to Slovakia. Seven species (3.0%) were considered as RE. Out of the two hornwort species, Phaeoceros carolinianus was included in the category NT, while Anthoceros agrestis is considered as LC.
A relatively large group is represented by species of the Data Deficient category (27 species), which reflected the insufficiently known distribution and endangerment of liverworts, but also taxonomic changes in the status of some species (e.g. Moerckia hibernica, Mesoptychia bantriensis, Lophozia silvicola).
In Europe, there are currently 461 liverwort and eight hornwort species, of which 22.5% and 25%, respectively, are evaluated as threatened   brevicaulis as VU in the European Red List of mosses, liverworts and hornworts . Anthropogenic changes in natural conditions and degradation of the ecosystems (e.g. groundwater decline, waterflow regulation, vascular plant succession, vanishing of wetlands and peatlands) cause decrease in populations of many liverwort and hornwort species or their complete retreat from natural habitats of Central Europe (Staniaszek-Kik and Woziwoda 2011; Dittrich et al. 2016). Factors that lead to these changes are mainly caused by agriculture, forestry, aquaculture, industry and traffic pollution, tourism, and residential development. Climatic changes in recent decades, especially long-term drought and heat, can reduce the population of several hygrophilous species.
In Central European conditions, hornworts as ephemeral plants grow in summer and autumn on bare soil, especially in fields and fallows. Climate changes with hot, dry summers and small amount of autumn rainfalls caused scarcely any records in recent years. However, long-term changes in distribution and chorology of hornworts cannot be evaluated yet, as their spores can survive in the latent state in the soil for long periods (Bisang 1996).