Data on the Distribution and Population Size of Amphibians in the Csík Mountains (Munţii Ciucului), Eastern Carpathians, Romania

László Demeter 1and Alpár Kelemen 2

1 Sapientia University, Libertatii Str. 1, Miercurea-Ciuc, Romania,
domedve@gmail.com
2 2Pond Ecology Group, Libertatii Str. 1, Miercurea-Ciuc, Romania,
kelemenalpar3@gmail.com

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KEYWORDS:

amphibian communities, Bombina variegata, Bufo bufo, Bufo viridis, Important Amphibian Areas, Lissotriton montandoni, Lissotriton vulgaris, Rana arvalis, Rana temporaria, Triturus cristatus

ABSTRACT

In this study we made a first step towards a map of amphibian breeding-habitat distribution in the Csík Mountains. We recorded amphibian species and made estimations of population size using spawn counts and breeding adult counts on an approximately 100 km2 area between 660 and 1500 m altitude above sea level. Nine species and seven sites with an outstanding abundance of amphibians were recorded. We propose the term Important Amphibian Areas and discuss criteria for this title.

INTRODUCTION

Amphibians are a globally threatened animal group (e.g. Beebee and Griffiths 2005) and a priority for nature conservation at the international and national level (EC Habitats Directive, Iftime 2005). They are relatively easy to observe and study in their breeding season, they have complex life cycles (Wilbur 1980), are locally abundant and thus play an important role in ecosystems (e.g. Davic and Welsh 2004), also they are good model organisms in ecological research and environmental education (Randler et al. 2005).

All the species occurring in Romania are protected (OUG 68/2007), however the enforcement of this status is very weak. At the same time, although there is a growing number of studies on amphibian distribution in Romania (reviewed in Fuhn 1960, Ghira et al. 2002, see also Hartel et al. 2010), in many areas there are still very few data about their distribution, and even less data are available about population sizes and trends. In order to properly implement nature conservation regulations, distribution and population size data are needed, and then the monitoring of selected populations.

The distribution and population sizes of amphibians is very weakly documented in the Eastern Carpathians, partly because of difficulties in access. In our study area, there are more data from the central part of the Csík Basin (Demeter 2004, Demeter and Mara 2006 a, b, Demeter et al. 2006) and just sporadic data are available from the Csík Mountains (Demeter et al. 2006).

The goal of this paper is to present the currently known distribution and population sizes of amphibians in a transect of the Csík Mountains.

MATERIAL AND METHODS

Between 2005 and 2010 we made spawn counts of two anuran species, Moor Frog (Rana arvalis) and Common Frog (R. temporaria), in the surroundings of Delne (Delnița) village (Demeter and Benkő 2008). In 2010 we made surveys in the mountain areas too, mainly in the territory of Pálfalva (Păuleni) commune, Jávárdi stream and Jávárdi Mountain, in the territory of Gyimesközéplok (Lunca de Jos) commune, surveying 145 breeding habitats, covering mostly a transect on the western side of the Csík Mountains (Fig. 1). The total covered area is approximately 100 km2. For the general description of the area see Demeter et al. 2011.

We used the breeding habitat (pond) based approach for the mapping of amphibian fauna as opposed to the locality-based approach (Hartel et al. 2010). We identified amphibian breeding habitats through transects that followed primarily streams and mountain ridges in the area. The position of each breeding habitat was registered by GPS, maximum water depth, length and width of the habitat, vegetation type and origin of the habitat were noted. We counted adult individuals in the case of the Common Toad (Bufo bufo), Green Toad (B. viridis), Yellow-bellied Toad (Bombina variegata), Edible Frog (Pelophylax kl. esculentus),Carpathian Newt (Lissotriton montandoni), Alpine Newt (Mesotriton alpestris) and counted spawn strings in the case of B. bufo and spawn clumps in the case of R. arvalis and R. temporaria.

Fig. 1. The studied administrative units

Fig. 2. Natural semipermanent pond on an alluvial fan, breeding habitat of Rana arvalis, R. temporaria, Lissotriton vulgaris and Triturus cristatus (photo taken on April 5, 2010).

Fig. 3. Puddle on a mountain ridge on an abandoned forestry road. Breeding habitat of Bombina variegata and Lissotriton montandoni (photo taken on May 23, 2010).

Fig. 4. Puddle in a valley along a forestry road. Breeding habitat for Bombina variegata, Bufo bufo, Lissotriton montandoni, Mesotriton alpestris (photo taken on May 11, 2010).

Fig. 5. Puddle in a valley on a relatively frequently used forestry road (used by horsecarts and cars). Breeding habitat for Bombina variegata, Bufo bufo, Lissotriton montandoni, Mesotriton alpestris, Triturus cristatus (photo taken on May 11, 2010).

Fig. 6. Puddle in a valley on the edge of a fen along a forestry road. Habitat of Lissotriton montandoni (photo taken on May 11, 2010).

Fig. 7. Bomb crater pond on a mountain ridge in Gyimes. Habitat of Bombina variegata and Lissotriton montandoni (photo taken on May 23, 2010).

Fig. 8. Hibernation habitat of Rana temporaria. A fen with a high density of springs in a valley side (photo taken on February 28, 2010).

Fig. 9. Male moor frog, in the Torda valley (photo taken on April 11, 2010).

Fig. 10. Courting Lissotriton montandoni and Bufo bufo tadpoles (photo taken on May 11, 2010).

RESULTS

The main amphibian breeding habitats in the studied area are: relatively large sized temporary ponds on alluvial fans (Fig. 2) of the basin, and shallow puddles along roads in the valleys and ridges of the mountains (Fig. 3-6). A peculiar habitat type is bomb ponds formed during World War II (Fig. 7). Deep, permanent standing water bodies are rare: there are very few small artificial ponds and a water reservoir.

At least one species has been found in 120 (83%) of the surveyed habitats.

The following species have been recorded: Bombina variegata, Bufo bufo, Pelophylax kl. esculentus, Rana arvalis, R. temporaria, B. viridis, Mesotriton alpestris, Lissotriton montandoni, L. vulgaris, Triturus cristatus. The most frequent species was B. variegata, and the rarest was M. alpestris (Fig. 11).

Rana temporaria was found in both the basin and the mountains, small artificial ponds and the water reservoir (Fig. 12). The largest numbers of spawn clumps was found between 660 and 850 m. In 2010 we counted 1195 spawn masses on a site.

Rana arvalis (Fig. 9) was found only in the surroundings of Delnița, a roughly 4 km2 area between 660 and 760 m altitude (Fig. 14). This is one of the largest populations in the country, on an isolated patch of wet meadows and alluvial fan ponds, estimated to between 700 and 1400 spawn masses per year. In 2010 we counted 1100 spawn masses on this site, representing 1100 breeding females.

Pelophylax kl. esculentus was found along a few streams in the low altitude part of the basin. Its relative rarity can be explained by the low number of large standing water bodies in this area.

Bufo bufo (tadpoles on Fig. 10) was found in both larger ponds and in mountain puddles. It was not found in most of the alluvial fan ponds (Fig. 16).

Bufo viridis was only found in the shallow pools of the Delnița quarry (Fig. 14).

Large populations of Lissotriton vulgaris and Triturus cristatus (Fig. 11) were found in the alluvial fan ponds, where they are predators of eggs and larvae of R. temporaria and R. arvalis. A few individuals were found in the valleys.

Bombina variegata is the most common amphibian species in the area, however, it is absent from most of the alluvial fan ponds (Fig. 14).

Lissotriton montandoni (Fig. 10) is the most frequent urodelan in mountain puddles. Large populations were found where a large density of deep roadside puddles is available (Fig. 13).

Mesotriton alpestris was found only in eight habitats, between 950 and 1400 m, in roadside puddles (Fig. 14).

Typical amphibian communities in the alluvial fan ponds consist of Rana temporaria, R. arvalis, Triturus cristatus, Lissotriton vulgaris while those of roadside puddles in the mountains consist of Bombina variegata, Bufo bufo, Lissotriton montandoni.

We found significant negative correlation between B. variegata and L. montandoni (Spearman r=-0.79, p=0.002, n=12) when counting only the cases when the number of at least one of the two species is larger than 20. We did not find such relationships between other species that share the same breeding habitat in large numbers.

Fig. 11. Frequency (pond occupancy) of amphibian species in the studied area in a decreasing order.

Fig. 12. Common frog spawn distribution in the studied area.

Fig. 13. Distribution of the Carpathian newt in the studied area.

Fig. 14. The distribution of Alpine newt, green toad and moor frog spawn in the studied area.

Fig. 15. The distribution of yellow-bellied toad in the studied area

Fig. 16. The distribution of common toad in the studied area.

DISCUSSION

Large amphibian populations represent scientific, educational and touristic values. Currently no conservation effort is made for any amphibian species in this area, although there are multiple threats to amphibians including habitat destruction, fragmentation, traffic and frog leg collection (Nemes and Kovásznai 2001, Demeter 2004). We consider that it would be useful to provide authorities with a list of sites where large populations or a large number of species are found. For such areas we propose the term Important Amphibian Areas (IAA), by analogy with Important Bird Areas used by Birdlife. An IAA would be a breeding habitat or group of breeding habitats with a 500 m radius circle plot around it. The average maximum movement distance for amphibians is about 2 km, Smith and Green 2005, Hartel and Öllerer 2009. Most species (B. variegata, Bufo bufo, B. viridis, R. arvalis, all the newt species) found during this study have much smaller movement distances than this except R. temporaria which performs long distance migrations through streams (Demeter and Mara 2006).

For the species found in this area, we propose the following arbitrary criteria for an IAA: at least 50 adult Bombina variegata or Bufo viridis or Lissotriton montandoni or L. alpestris, at least 100 Rana arvalis or Lissotriton vulgaris or Triturus cristatus, at least 500 Rana temporaria or Bufo bufo.

According to these criteria, we identified seven IAA (Table 1). From these, two (sites 1 and 3) were already known to host important amphibian populations (Demeter et al. 2006) and five are new. The amphibian community of the lowland sites (1 and 2 in Table 1) are represented by five species (B. variegata, L. vulgaris, R. arvalis, R. temporaria, T. cristatus). The water reservoir and especially the inflow areas of three streams are important B. bufo and R. temporaria breeding sites. The other four are connected to forest roads (sites 4-7 in Table 1), and are important for B. variegata and L. montandoni, but several other species are found in smaller numbers: B. bufo, M. alpestris, R. temporaria, T. cristatus).

Table. 1. List of identified Important Amphibian Sites

  Latitude Longitude Altitude Habitat type Species
1 46.8 25.4 700 Alluvial fan ponds B. variegata, L. vulgaris, R. arvalis, R. temporaria, T. cristatus
2 46.424 25.83 750 Alluvial fan ponds R. arvalis, R. temporaria
3 46.448 25.89 850 Reservoir B. bufo, R. temporaria
4 46.416 25.91 930 Roadside pond B. variegata
5 46.438 25.958 1000 Wheel track puddles B. variegata
6 46.429 25.98 1110 Wheel track puddles L. montandoni
7 46.487 26.014 1340 Wheel track puddles L. montandoni

Our survey probably underestimated the frequency and population sizes of B. variegata. During our study period there was relatively little precipitation, but it was followed by a long and exceptionally wet period of two months which created excellent breeding conditions for this species. It was surprising to find that M. alpestris is very rare in the study area, and also to see the very high abundance of L. montandoni.

The Delnița quarry represents a special habitat where B. viridis dominates. In the mountains, most breeding habitats are roadside puddles created by logging. This indicates that human activities create in some cases good breeding conditions for amphibians. The head areas of the streams that flow westwards from the main watershed of the Eastern Carpathians are very wet, perhaps explained by the underlying geology. Here logging created a large abundance of puddles and the area is not heavily logged at present, all these factors providing excellent breeding conditions for L. montandoni, B. variegata and even B. bufo. It would be interesting to further study the ecology of these extremely crowded small water bodies.

Our earlier data (Demeter and Mara 2006) suggest that a large proportion of adult R. temporaria migrate to the low altitude areas through the flooding streams in early spring. The puddles in the mountains have small numbers of spawn. This is a particularly good case of ecological connections. Most of the common frogs that breed on site 1 and 2 (Table 1) come from more than 1-3 km upstream. We identified an important hibernation site in this area, a 2.5 ha fen. There is a strong case to protect the wintering, migration and feeding habitats of protected amphibians as well as their breeding grounds.

Hay meadows probably pay an important role in the terrestrial phase of amphibian life-cycle as feeding and dispersal habitats (see Hartel 2005, Hartel et al. 2010). However, this was not yet studied in this area.

On site 1, L. vulgaris and T. cristatus mostly feed on R. arvalis and R. temporaria eggs in the breeding season of the latter two species (pers. obs.). At this point we can not quantify the effect of newt predation on these two frog species. In the shallow puddles of the mountains, it is easier to count amphibians, and we found a significant negative correlation between B. variegata and L. montandoni. Part of the explanation of this relationship is that L. montandoni would predate toad eggs, and toads avoid puddles with a large density of newts.

AKNOWLEDGEMENTS

This research was part of the project “Mountain hay meadows – hot spots of biodiversity and traditional culture” funded by Dr Barbara Knowles and the UNDP GEF.

REFERENCES

Beebee, T. J. C, Griffiths, R. A. 2005 – The amphibian decline crisis: A watershed for conservation science? Biological Conservation 125: 271-285.

Beshkov, V. A., Angelova, B. A., 1981 – An unusual reproductive migration of the common frog (Rana temporaria). Ekologiya (Sofia) 8: 34-42.

Davic, R. D., Welsh, H. H. Jr. 2004 – On the ecological roles of salamanders. Annual Review of Ecology, Evolution and Systematics 35: 405-434.

Demeter, L., 2004 – Study of the dynamics of a Rana temporaria population near Miercurea-Ciuc. A Csíki Székely Múzeum Évkönyve 2004: 323-333.

Demeter, L., Benkő, Z., 2008 – Note on a large population of Rana arvalis in Romania. Zeitschrift für Feldherpetologie Supplement 13: 355-358.

Demeter, L., Csergő, A. M., Sándor, D. A. 2011 – Natural treasures of the Csík Mountains. In: Mountain hay meadows: hotspots of biodiversity and traditional culture, Ed. Barbara Knowles, Society of Biology, London.

Demeter, L., Mara, Gy., 2006 a – Rana temporaria mass migration. Herpetological Review 37(2): 211.

Demeter, L., Mara, Gy., 2006 b – The distribution and population size of Rana arvalis in the Ciuc Basin. A Csíki Székely Múzeum Évkönyve 2005: 439-449.

Demeter, L., Hartel, T., Cogălniceanu, D., 2006 – Distribution and conservation status of amphibians in the Ciuc basin, Eastern Carpathians, Romania. Zeitschrift für Feldherpetologie, Supplement 10: 217–224.

Demeter L., Pásztohy Z., Csergő A.-M., Cărăuş I., 2005 – Terrace ponds in the Ciuc Basin: A preliminary characterization. Stud. Cercet. Biol., Univ. Bacău 10: 19–23.
Fuhn, I. E., 1960 – Amphibia. Fauna Republicii Populare Române, vol. 16. Editura Academiei Republicii Populare Române, Bucureşti, 288 pp.

Ghira, I., Venczel, M., Covaciu – Marcov, S. D., Mara, Gy, Ghile, P., Hartel, T., Török, Zs., Farkas, L., Rácz, T., Farkas, Z., Brad, T., 2002 – Mapping of Transylvanian herpetofauna. Nymphaea 29: 145-201.

Hartel, T., 2005 – Aspects of breeding activity of Rana dalmatina and Rana temporaria reproducing in a seminatural pond. North-Western Journal of Zoology 1:5-13.

Hartel, T., Öllerer, K., 2009 - Local turnover and factors influencing the persistence of amphibians. North-Western Journal of Zoology 5: 40-52.

Hartel, T., Öllerer, K., Cogalniceanu, D., Nemes, Sz., Moga, C. I., Demeter, L., 2010 – Pond-based survey of amphibians in a Saxon cultural landscape from Transylvania (Romania). Italian Journal of Zoology 77: 61-70.

Hartel, T., Demeter, L., Cogălniceanu, D., Tulbure, M., 2006 – The influence of habitat characteristics on amphibian species richness in two river basins of Romania. Pp. 47-50. In Vences, M., Köhler, J., Ziegler, T. & W. Böhme (eds): Herpetologia Bonnensis II. Proceedings of the 13th Congress of the Societas Europaea Herpetologica.

Hartel, T., Schweiger, O., Öllerer, K., Cogalniceanu, D., Arntzen, J. W., 2010 – Amphibian distribution in a traditionally managed rural landscape of Eastern Europe: probing the effect of landscape composition. Biological Conservation 143: 1118-1124.

Iftime, A., 2005 – Amphibia. P. 112. In Botnariuc, N. & V. Tatole. (eds.): Cartea roşie a vertebratelor din Romania. Academia Româna & Muzeul Naţional de Istorie Naturală "Grigore Antipa". Bucureşti.

Nemes, Sz., Kovásznai, Cs., 2001 – Amphibian harvesting in Romania. FROGLOG 44/4.
Randler, C., Ilg, A., Kern, J., 2005 – Cognitive and emotional evaluation of an amphibian conservation program for elementary school children. The Journal of Environmental Education 37: 43-52.

Smith, M. A, Green, D. M., 2005 – Dispersal and the metapopulation paradigm in amphibian ecology and conservation: are all amphibian populations metapopulations? Ecography 38: 110-128.

Wilbur, H. M., 1980 – Complex life cycles. Annual Review of Ecology and Systematics 11: 67-93.