Areas of endemism and conservation status of Galianthe species (Spermacoceae, Rubiaceae) in the Neotropics

Abstract

Areas of endemism are a standard unit of biogeography and are commonly used for analytical biogeographic analyses as a criterion to identify areas for conservation. Galianthe is a genus of 56 species of mainly herbaceous plants from the family Rubiaceae found in the Neotropics, occurring in campos rupestres (quartzitic rock outcrops), cerrado (savanna), lowland grasslands, campos de altitude (highland grasslands), sasonally dry tropical forests (caatinga vegetation), and savanna hillsides. Currently, the conservation status assessment is only known for eleven species of Galianthe, and there have been no previous attempts to identify areas of endemism for the genus. In view of this, we used the NDM/VNDM software to analyze the distribution of the 56 species of Galianthe to identify areas of endemism and to recognize which species define each area. We also evaluated the conservation status of forty-five species for first time, according to the International Union for Conservation of Nature (IUCN) guidelines. Our finding identified 12 areas of endemism with three cell sizes, mainly in the eastern part of Paraguay and southern Brazil. Illustrating the general biodiversity crisis, 41% of the Galianthe species (23 spp.), were evaluated as Endangered due to their degree of endemism and destruction of their habitat, while 31 species were evaluated as not threatened and two species had Insufficient Data. In turn, only five threatened species were found within or on the periphery of protected areas. We consider that although protected areas are designed to protect biodiversity, in recent decades they have experienced different degrees of threat. Due to the high risk of many species of the genus, it is necessary to consider restoration (as a complement to conservation) of the processes that maintain grasslands to conserve unique, endemic and threatened species.

Key words:

• areas of endemism
• conservation assessment
• Neotropics
• rare plants
• Rubiaceae
• threatened species

Acknowledgments

We are deeply indebted to Elsa Leonor Cabral and Mariela Nuñez Florentin for fruitful discussions and comments on the manuscript. JEF thanks Barbara De Madrignac and Mariana Martínez from Paraguay; José Floriano Barea Pastore and Michelle Mota from Brazil; Eder Chilquillo Torres from Peru; Mercedes Sosa and Mariela Nuñez Florentin from Argentina for their hospitality during the fieldwork.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental material

Supplemental material for this article can be accessed here: http://dx.doi.org/10.1080/14772000.2022.2025946.

Associate Editors: Oscar Pérez-Escobar and Peter D. Olson

Additional information

Funding

This work was partially funded by the Universidad Nacional del Nordeste (PI A013-2013 and PI 16P001 grants) and from ANPCyT-Foncyt (PICT 2016-3517) to JEF and RMS. Also, JEF thanks Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET) for the grants awarded that supported this work. SJ was funded by a Carlsberg Foundation Semper Ardens grant to the ‘MegaPast2Future’ project (grant CF16-0005 to J-CS). J-CS and SJ acknowledge financial support from VILLUM FONDEN through the VILLUM Investigator project 'Biodiversity Dynamics in a Changing World' (grant 16549 to J-CS) and from Troels Myndel Petersens Botanisk Taxonomiske Forskningsfond.