Assessing preservation priorities of caves and karst areas using the frequency of endemic cave-dwelling species

Abstract

Abstract:Endemic and rare species as bioindicators of habitat vulnerability were used to develop protection and management plans for biotope prioritization (mainly islands habitats, lava tubes or groundwaters). Due to their narrow distribution, the endemic species (species confined to a restricted geographic area) are more susceptible to ecological disequilibrium and habitat loss than the widespread ones. Consequently, endemics become endangered in the context of ecological disturbance caused by anthropogenic pressure, making them suitable candidates to assess environmental preservation needs. Taking into consideration that most of the stygobitic and troglobitic species are endemic and confined to specific karst areas, based on their association and frequency we propose an endemicity index (EI) adapted to the fragmented nature of the cave habitat. We used a double ranking methodology: (1) ranking the endemic species according to their frequencies in caves, and (2) ranking the caves according to their EI computed for a geographic area. Further, by mapping the caves based on their related EI, we identified the hotspots of vulnerable karst areas. The EI has been developed using as case study of 380 caves from Romania, known up to now to be inhabited by a total of 278 endemic stygobitic and troglobitic species and subspecies. In our study area, 35 out of 380 caves with endemic species, narrowly distributed to karst areas of the Carpathian massifs and Dobrogea, had a considerable high EI. The EI proves to be highly sensitive to unique taxa (endemics recorded in only one cave) and also to other endemic taxa -recorded in more than one cave. However, all the endemites are confined to a specific geographic area (in this case of study -the Carpathians and Dobrogea karst area). EI provides a reliable criterion to rank caves using the contribution of endemic species in order to assess cave and karst vulnerability and prioritize them for environment protection management.

Cave millipede diversity with the description of six new species from Guangxi, China

“…Three additional subterranean-adapted species occurred in multiple caves with maximum distances ranging from 81.27 and 137.6 km (Table 3). As many troglomorphic arthropods are identified as short-range endemic species, occurring in a single cave or geological formation (Reddell 1994, Culver et al 2000, Christman et al 2005, Deharveng et al 2008, Tian 2011, Harvey and Wynne 2014, Gao et al 2018, Nitzu et al 2018 and that rivers and valleys/ lowland areas often result in vicariance (Barr 1985, Faille et al 2015, Katz et al 2018, the genetic relatedness of at least these three species should be further examined using genetic techniques. While these species may be morphological similar, we suggest they may be genetically distinct -potentially representing different subspecies or lineages.…”

Finding answers in the dark: caves as models in ecology fifty years after Poulson and White

“…Being delicate and sheltered environments, caves have been widely used to quantify the impacts of human activities on different ecosystem components and to discuss conservation issues (Tercafs 1988, Watson 1997, Slaney and Weinstein 1997, Trajano 2000, Harvey et al 2011, Reboleira et al 2011, Culver and Pipan 2014, Wynne et al 2014. As the funding available for conservation of biodiversity is limited (Meyers et al 2000), special focus has been given to develop cave priority indexes to obtain objective criteria for channeling conservation efforts (Borges et al 2004, Michel et al 2009, Souza-Silva and Ferreira 2015, Jaffé et al 2016, Nitzu et al 2018; see also Rabelo et al 2018 for a comparison of different indexes). A global mapping of subterranean biodiversity hotspots is also emerging (Culver and Sket 2000, Culver and Pipan 2009, Trajano et al 2016, Sousa-Silva and Ferreira 2015, although the definition of hotspots is currently based on arbitrary criteria -sites hosting more than 20 stygobionts/troglobionts (Culver and Sket 2000).…”

Comment on “Assessing preservation priorities of caves and karst areas using the frequency of endemic cave-dwelling species” by Nitzu et al. (2018), Int. J. Speleol., 47 (1): 43-52

“…In a recent paper published by Nitzu et al (2018), the authors propose an algorithm to identify "hotspots of vulnerable karst areas" that uses frequency of endemic "cave-dwelling species". The authors viewpoint is that the occurrence of endemic troglobionts and stygobionts, or cave-dwelling species as given in the title, in 3-4 caves up to a maximum of 37 caves, can be used to rank caves in terms of their vulnerability.…”

“…Out of more than 12,000 caves known in Romania, 830 are considered in Nitzu et al (2016Nitzu et al ( , 2018, with many others that might be biospeleologically overlooked. In order to be certain that a species is present in one or more caves, repeated sampling is needed.…”

“…By ranking caves that are highly vulnerable to anthropic impacts at low levels based on quantitative data is as dangerous as declaring the caves free to any usage. Although Nitzu et al (2018) promised to add other criteria to cave ranking, we consider that one cannot start prioritizing caves for protection based solely on the number of species and their frequency and ignoring the actual threats. Many strategies of caves protection also include the possible or existent threats (e.g., Souza-Silva et al, 2015;Ferreira, 2016, andreferences in Nitzu et al, 2018).…”