Black salamander from Mt.Prenj

Introduction

Alpine populations of black salamanders belong to the subspecies Salamandra atra atra (Laurenti, 1768) and are continuously settled along the Alps from France to Slovenia. Salamandra atra prenjensis is an endemic subspecies characteristic to the Dinarides. The distribution between these two subspecies is discontinuous. Prenjensis sporadically appears in an unknown number of fragmented, isolated populations mostly restricted to high mountain areas. It inhabits Croatia, Bosnia and Herzegovina - BiH, Montenegro, Serbia, Kosovo and Albania. In BiH , it appears on Prenj and Čvrsnica mountain. The finding of Werner for mountain Treskavica has not been confirmed by the year 1895.

The habitat types in both areas are very different: In the Alps, populations have a significantly wider vertical distribution (500m - 2500m) and are mainly located in mixed dedicious forests; Dinaric populations live on higher altitudes with narrow vertical distribution (900 - 2000m) mostly above the tree line on open humid meadows. Although apparently there does not seem to be any significantly visible difference between the two subspecies, it is considered that the isolation between the two, and different habitats affected their morphology, behavior and genetic structure. Sofia Mikšić, who described the prenjensis subspecies in 1969, states that Dinaric individuals are slightly smaller and brighter in black coloration compared to Alpine once and have rounded palatal teeth as opposed to parallel distributed palatine teeth of their Alpine cousins. 

Project objectives

The status of prenjensis as a separate subspecies is not fully accepted within the scientific community due to lack of data. The (sub)species is special because is completely black, gives birth to 1-2 living youngs after 3 years of pregnancy, and inhabits harsh habitats restricted to high altitude areas, thus resembling island's populations - all characteristics that contribute to its vulnerability. Poor knowledge about distribution and biology of these (sub)species in the Dinaric region, compromises efforts for setting up appropriate measures for its protection.
The project aims to establish a legalized, permanent and sustainable regional conservation system for prenjensis populations: The conducted research throughout this project will contribute in prooving the subspecies status which would facilitate legal protection of Prenj and Čvrsnica Mts. as areal of prenjensis in B&H, for long term conservation of this amphibian species. 

Field activities

Distribution analysis: Since 2013 regularly field research is carried out in B&H, in the mountains Treskavica, Maglić, and Cincar for which previous studies have shown a possibility of (sub)species occurence. Distribution analysis since year 2015 are carried out also in Croatia. Starting from summer 2016 field research will start in the southernmost distribution areal of the subspecies - Prokletije Mts.

Ecology study: During field activities, the aim is to collect as much data on species biology, population ecology and information about the ecosystem that salamanders inhabit. We record environmental abitoic factors using handheld data loggers (temperature, humidity and dew point); data loggers with USB connection are left on the field throughout the whole year to collect microenvironmental abiotic factors.  Comparative ecology analysis are beeing performed between BiH (highland) and Croatian (lowland) populations; these analysis include collecting: (a) feeding data - stomach flushing of individuals and collecting pedofuna in pitfall traps for food availibilty and feeding preferences study; (b) temperature ecology data - body temperature of individuals is beeing measured in the field together with microhabitat temperatures - availability - these data will be used to understand what is the range of optimal conditions for their functionality? Do they manage to thermoregulate by chosing microhabitats which are offering these best conditions? This knowledge is necessary to understand and predict impact of climate change on populations survivorship.

Monitoring activities: Since 2015, monitoring of salamander populations on Prenj and Čvrsnica (BiH) and Gorski Kotar (Croatia) are beeing conducted using transect methodology. Transect data will give insight into the number of individuals, structure, dispersion and density of population.

More information about other ongoing field activities can be found here and here

Vulnerability and protection

The Alpine salamander is on Annex II of Bern Convention (Convention for Conservation of European Wildlife and Natural Habitats) and Annex IV of the Habitat Directive (Convention for Conservation of global Biodiversity). Does not have CITES status.

Proving subspecies status could affect its relocation on Annex II of Habitat Directive, as it is the case of Salamandra atra aurorae , thus having a significant signal function in the designation of critical NATURA2000 habitats (B&H entered in the procedure of defining Natura 2000 area network and signed the treaty of both Conventions). In B&H, although listed on the red list, the species is not protected by the law and its habitat is under severe human pressure (illegal grazing, deforestation, fires, construction of touristic infrastructure). Fire on Prenj in 2012 damaged large habitats for Prenj populations and their recovery will be long lasting. Global climate changes increase the frequency of such events and bring unpredictable challenges to population survivorship.

According to IUCN categorization, the Alpine salamander has LC (Least Concerned) conservation status which is justified for alpine populations. Dinaric populations deserve different approach in defining their conservation status primary because of their extremely fragmented and narrow vertical distribution and isolation from their alpine relatives. According IUCN criteria, prenjensis populations should have EN (Endangered) conservation status which is additonally confimred if vulnerability is assesed using DELH approach (Distribution, Ecology, Life History Data) at the level of Bosnia and Hercegovina (B&H) where it should be treated as high-priority species for consevation.

Interesting facts

Maximum registered life span in the wild is 17 years; in captivity it is believed that they can live up to 40 years.

During hibernation their body cells produce glycerol which acts as a type of antifreeze that prevents their freezing (formation of ice crystals in body cells).

Among all fertilized eggs, only one or two embryos survive and continue developing in the fallopian tubes of the mother. Other fertilized eggs serve as food for these newly formed embryos , which is the only example of intrauterine cannibalism in the world of amphibians. If embryos develop unevenly, the "weaker" one will stays longer in the body of the mother and can be born after several days or even weeks from the birth of the first. Once born, the juveniles are ready for independent life. 

They have big regeneration potential: they can regenerate any part of the lost body (except spinal cord and central nervous system). The period of regeneration of e.g, a complete lost limb (entire leg or arm) can last from one month (younger specimens) up to about three months in adults. After that, the new limb becomes fully functional.

They produce a white poisonous substance in the body glands of not entirely known composition for which is believed to have neurotoxic properties. 

Other analyzes within the project

Analysis of chytridiomycosis - a disease that is responsible for mass extinction of amphibian species worldwide and that is actively spreading across the globe. Analyses are performed in order to determine whether the pathogen fungi - Batrahochytridium dendrobatidis (Bd) has invaded the territory of B&H Dinarides thus representing a threat for  prenjensis survivorship. During field researches several unusual deaths cases of these individuals were registered and Bd was suspected to be the responsible agent. Fortunately, analyzes have proved negative.
Morphological analysis - play an important role for proving the status of subspecies; Comparative morphological analyzes are carried out with Austrian individuals in order to reveal whether the isolation of these two populations led to expression of unique morphological characteristics or other functional patterns.
Reproductive analysis - Alpine salamander individuals give birth to two completely metamorphosed youngs after 2-3 years of gestation ("pregnancy"). Due to harsh conditions that prenjensis inhabits, gestation time might be prolonged and preeliminary analyzes showed that majority of females gave birth to only one young. Proving this hypothesis would have significant implication in conservation measures especially in estimating number of individuals in upcoming generations.