The species Valeriana praecipitis (Caprifoliaceae), new to science and endemic to the Ñuble Region, Central Chile, is formally described. Morphological data support its placement in a new species, clearly different from V. philippiana. A detailed description, insights about its habitat and ecology, distribution map and illustration are provided. A table of comparison is also given with the morphological characters discriminating V. praecipitis from V. philippiana. The species is assessed as Endangered (EN) under the IUCN categories.

Andes, biodiversity, cliffs flora, Ñuble Region, taxonomy

The Valerianaceae family was included in the Caprifoliaceae family by the Angiosperm Phylogeny Group III (APG III 2009). Although some authors continued using Valerianaceae for several years (e.g., Kutschker 2011), the family remained within the Caprifoliaceae in the APG IV (2016). Caprifoliaceae includes about 960 species in approximately 41 genera (Wang et al. 2020), having an almost cosmopolitan distribution, with centres of diversity in eastern North America and eastern Asia (Xu and Chang 2017).

Valeriana is one of the most diverse genera within the Caprifoliaceae, with a worldwide distribution, and centres of diversity in tropical areas of Central-America and to the south along the Andes mountains (Kutschker and Morrone 2012). In South-America, Valeriana species are present in Peru, Bolivia, Brazil, Chile and Argentina (Zuloaga et al. 2008). In Chile, Borsini (1966) described 42 species, while the most recent assessment identified 40 species in the Andes mountains of Chile and Argentina, between latitudes 33° and 56° S (Kutschker 2011). This area was identified as a centre of diversification of Valeriana species (Kutschker and Morrone 2012). In Chile 44 species are accepted, of which 18 are endemic, and interestingly, to date no introduced species has been found so far (Rodríguez et al. 2018). All species are herbaceous (Rodríguez et al. 2018) and many of them are distributed in high-altitude mountainous locations, usually above 1000 m elevation (e.g., V. stricta Clos, V. philippiana Briq.). They can also be restricted to dry soils (e.g., V. corynodes Borsini) or in permanently wet soils (e.g., V. fonckii Phil.). Recently, only one species new to science has been formally described, V. nahuelbutae Penneck. (Penneckamp 2020) and few new geographical locations have been found for other species (e.g., Kutschker 2011; Teillier et al. 2020). Furthermore, for most species little is known about their ecology or ethnobotany, and to this day, only one of the Chilean species have had formal conservation assessments completed according to the IUCN criteria (Valeriana senecioides Phil.; MMA 2021).

The Central Chilean Andes mountains are recognised as a centre for endemism in South-America (e.g., Villagrán and Hinojosa 1997; Arroyo et al. 2006). In addition, the Andean ranges of the Ñuble Region were declared as a Biosphere Reserve in 2011 (San Martín 2014; Fig. 1) and this area is of increasing interest since a new genus was recently described (Villarroel et al. 2021). However, several species in the region remain severely threatened (Hechenleitner et al. 2005). Intensive land-use changes due to human activities have affected vast extensions of almost all types of vegetation in Central Chile, including high-Andean habitats (Arroyo et al. 2006). In addition, global climate change is a serious threat to montane habitats that have reduced in size, are geographically isolated, and where the environmental conditions have changed significantly across small distances due to steep slopes (Báez et al. 2016).

Figure 1. 

Distribution maps of Valeriana praecipitis A Chile B Ñuble Region C sites of V. praecipitis (yellow stars) and extent of occurrence (red line).

In this manuscript we describe a species of Valeriana located in the Central Chilean Andes at around 36° S latitude and clearly distinguishable from other species by its remarkable silvery-green basal leaves. In the following sections, a detailed account on how the species was discovered is given as a formal description. In addition, a distribution map, insights about its habitat and ecology, conservation status, and illustrations are provided.

Pollen evidence indicates that Valeriana is a Holarctic genus that might have arrived from the northern hemisphere, perhaps before the uplifting of the Andes during the Pleistocene (Kutschker and Morrone 2012). The authors found an endemism node area between latitudes 34° and 37° S, suggesting a diversification centre for Valeriana after a long period of isolation, caused by the Andes uplift. The same scenario might have occurred with other genera such as Berberis L., Ribes L., among others, indicating a complex centre of endemism of high conservation value (Moreira-Muñoz and Muñoz-Schick 2007). In the same way the genus Valeriana is key to understanding Andean biogeographic history (Kutschker and Morrone 2012), evolutionary processes that occurred in the area could have given rise to locally endemic species such as V. praecipitis, Rayenia malalcurensis and Viola chillanensis Phil. (Violaceae) (RBG Edinburgh 2021).

The discovery of V. praecipitis in southern South-America follows the recent discovery of Rayenia malalcurensis, a newly described endemic genus and species found in the same area. As mentioned before, since the revision of Kutschker (2011), new locations and a new species were described. These discoveries suggest that both the region and the genus may reveal additional interesting botanic surprises. Although no genetic analysis was performed to determine its phylogenetic affinities, the comparison of morphological characteristics with its closest species shows notable differences in 11 out of 13 sets of characters (Table 1), in addition to a distance between their recorded distributions of approximately 410 km. The species is unmistakable, easy to recognize from other species in the area, especially in spring and summer due to its remarkable silvery-green basal leaves. However, it is difficult to find given the steepness of the sites where it occurs. Its extreme rarity and inaccessibility are undoubtedly the reasons why it has evaded discovery up until the present time.

In addition to consistent morphological differences, V. praecipitis stands out from other species of the genus due to its specific ecological habitat. Few other Valeriana species are able to grow abundantly in damp rock-cliffs at this high altitude, directly rooted in fissures or small soil pockets (e.g., V. chilensis Borsini in Chile or V. ruizlealii Borsini in Argentina). Rock-cliffs are challenging habitats with high erosion rates, limited soil depth and nutrients availability (Mathaux 2017; March-Salas et al. 2018). Mountain microclimatic conditions at high elevations are also severe due to high insolation and extreme low temperatures (Gale 1972). To adapt to these conditions, the species has a woody rhizome that can be more than 30 cm long and 5–20 mm in diameter, perhaps the largest of any Valeriana species. In addition, its deciduous leaves allow this species to avoid freezing temperatures and the presence of snow. These environmental conditions could have triggered the adaptation phenomenon mentioned above, and eventually speciation processes as suggested by Kutschker and Morrone (2012).

Little is known about rare and endangered species growing in the southern Andean cliff ecosystems, and many open questions remain. Future research needs to be done to identify morphological and physiological adaptations to grow under harsh soil and climatic conditions that could shed light on the future of Andean plant communities in the face of climate change. For instance, how new climatic scenarios could affect their area of occupancy? Are they able to migrate? Or more precisely, how extreme and persistent climatic conditions, like the ongoing mega-droughts, might affect the physiological performance of these species, perhaps pressing viable populations’ threshold to the edge. The recent finding of V. praecipitis and Rayenia malalcurensis, in addition to other rare and endemic species, adds to the importance of monitoring and promoting the conservation of these species (Moreno-Gonzalez et al. 2019), especially those of Andean cliff ecosystems.

V. praecipitis is not present in any public protected area in Chile (Fig. 1B). In 2011, the Andean and pre-Andean sectors of the Ñuble Region and north of the Biobío Region were declared a UNESCO World Biosphere Reserve (San Martín 2014). All the known subpopulations of V. praecipitis are found within this Biosphere Reserve, except the one located in the surroundings of Laguna Añil. However, although they are internationally recognized, Biosphere Reserves protection is not guaranteed by Chilean legislation. Actually, all sites are in privately owned lands with an overall low level of anthropic change. Without any formal protection, the area is highly susceptible to be affected by the construction of hydroelectric dams, mining industry, unregulated animal farming and unsustainable tourism. The high biodiversity levels of this area (e.g., Villarroel 2019), including the presence of narrow range and threatened species such as V. praecipitis and R. malalcurensis and the high degree of threat of the Andean region, should give priority to the conservation of Andean territory of the Ñuble Region. Such conservation priority is ever more urgent in the light of future increasing trends of more frequent and severe fires (e.g., McWethy et al. 2021).

Another threat specific to cliff vegetation is the possible impact that rock-climbing could cause. In Chile (and worldwide) rock-climbing is of increasing interest, attracting more people to the mountains (Bogges et al. 2021), and climbers and hiker’s organizations are rightly asking for policy to change to allow for more open access to mountainous areas. However, with a greater number of people accessing mountain cliffs, the risk of negative human impacts would increase (Clark and Hessl 2015). So far, because of their remoteness and inaccessibility, Chilean cliff ecosystems have remained relatively unaltered by human impacts. The lack of access is not only due to a lack of trails, but also because many mountainous areas are privately owned. In the future, the major challenge will be to find the most effective strategy to conserve ecosystems, while maximizing the social benefits of access to mountains.

Fieldwork was financed by FONDECYT N°1181956, and the Instituto de Conservación, Biodiversidad y Territorio, UACh. Alejandro E. Villarroel was supported by CONICYT magister fellowship (22201444). Ricardo Moreno-Gonzalez was supported by DAAD/BECAS Chile, 2014 (57144001) during early stages of the study design. We express our gratitude to the owners and administrators of the private sites where the plant was found, especially to Elías Acuña and Esau Marin. The authors would like to thank the curators of CONC, EIF, JBN, and SGO, especially Jimena Arriagada. We are indebted to Martin Gardner and Nicolás Lavandero for the support and revision of the manuscript. Thanks to Marco Duretto and an anonymous reviewer for their helpful suggestions during the reviewing process of this manuscript. We are grateful to Arón Cádiz-Véliz for the illustration of the species. Thank you so much to our field partners: Gonzalo Ossa, Eduardo Ponce, Rayen Neira and all members of the Bullileo Team.