Wetlands Management for Little Crake (Porzana Parva) Conservation in a “Natura 2000” Site
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2011 2nd International Conference on Environmental Science and Development IPCBEE vol.4 (2011) © (2011) IACSIT Press, Singapore Wetlands management for Little Crake (Porzana parva) conservation in a “Natura 2000” site A.N. Stermin, L.R. Pripon, A. David and I. Coroiu Babeş Bolyai University, Faculty of Biology and Geology, Dept. of Ecology and Taxonomy Cluj-Napoca, Romania [email protected] Abstract— Currently, around a quarter of all rail species are This species inhabits emergent vegetation in wetlands, globally threatened. Among these, the little crake (Porzana flooded valleys and water bodies like ponds and ditches [6, parva) is considered a conservation priority in Europe, and is 11]. In Europe, little crake populations are in decline [3]. The listed in Appendix I of the EU Wild Birds Directive, Appendix main threats to little crake populations come from habitat II of the Bern Convention, and Appendix II of the Bonn loss [10] and defective management of areas in which it lives Convention. In Europe, the main threat to little crake [9]. The little crake is poorly studied, because it is a secretive populations is represented by habitat loss. Our study species and its habitat is difficult to penetrate [11]. demonstrates how habitat loss, defective management of The main goals of our study is to show how habitat loss, habitats, and interspecific interactions with water rail (Rallus defective management of habitat, and interspecific aquaticus) are collectively contributing to the decline of little competition with water rail (Rallus aquaticus) contribute to crake effectives. We surveyed five wetlands from the Fizeş Basin, a “Natura 2000” site, located in the central part of the the decline of little crake effectives, in a context where the Transylvanian Plane of Romania (24°10’ E; 46°50’ N). During water rail is a very aggressive competitor [5] and the niches May and August 2010 we located the nests, measured the water of these two species partially overlap [6]. depth, and density of vegetation at each nest site. Also, we approximated the percentage occupied by cattail (Typha) and II. MATERIALS AND METHODS reed (Phragmites) around each nest and for all the marsh The study area is located on the Fizeş Basin, in the vegetation of each wetland. At little crake nest sites, the depth central part of the Transylvanian Plane, in Romania (24°10’ of the water varied from 40 to 91 cm, vegetation density ranged E; 46°50’ N). The wetlands surveyed here represent 1/3 from from 321 to 467 plant stems per square meter and the all Transylvanian wetlands [7]. Fizeş Valley is one of the percentage of plant species was 100% for cattail. By Romanian Important Birds Area, and was recently comparison, for water rail nest sites the depth of water varied designated a “Natura 2000” site (Special Protected Area) [7]. between 8 to 45 cm, vegetation density ranged from 240 to 554 We studied five wetlands in the Fizeş Basin out of a total plant stems per square meter, and the percentage of the plants of 17. The surface of the wetlands under study varies from species ranged from 0 to 100% for cattail and in the same way 19 to 253 ha. Each lake has its particularities in terms of for reed. From historical data we found that all of the five marsh vegetation type, water level and origin. Most wetlands wetlands that we studied are undergoing sedimentation. This process leads to the replacement of cattail communities by reed from Fizeş Basin are man-made and used as fishing ponds; communities and thus the loss of habitat preferred by little only two of them (Pike Lake and Legii) are natural. crake. In the context where the niches of water rail and little Pike Lake is a natural wetland with a maximum depth of crake overlap, we assume that competition with Rallus 7 m, but with a large marsh vegetation area around, where aquaticus is another factor leading to the Porzana parva the water level does not exceed 1.5 m. On this lake, because population decline. We highlight the importance of increasing of water depth and vegetation structures, communities are the water level, reforesting the hills surrounding the wetlands, dominated by reed. and maintaining the local habitat diversity as a solution for the Legii wetland is another natural wetland, which in 1970 conservation of Little Crake and other bird species. was a lake with a rich avifauna, but today is a marsh with a maximum of 1 m water level, covered 90% by reed. Keywords- wetlands management, sedimentation, little crake, Sic wetland is the largest reed bed area from the water rail, competition. Transylvanian Plane. Vegetation communities here are dominated by reed and water level does not exceed 1 m. I. INTRODUCTION Cătina and Sucutard ponds are man-made, built by Currently, around a quarter of all rail species are globally embankment. Currently, they have high habitat diversity, threatened. Since 1600, at last sixteen species have become where vegetation communities are dominated by reed on the extinct [10]. A species that is vulnerable and considered a shore part and by cattail on the inwards part of the lake. priority for conservation in Europe, listed on Appendix I of Data was collected between May and August 2010. the EU Wild Birds Directive, Appendix II of the Bern During this time, some of the places of the pond suitable for Convention, and Appendix II of the Bonn Convention is the nesting of little crake and water rail were checked at intervals little crake (Porzana parva). of 2 to 3 days [13]. In the search for nests, we used a transect method [1]. 91 We measured the water depth and the density of TABLE II WATER RAIL HABITAT CHARACTERISTICS AT THE NEST vegetation at each nest site. Also, we approximated the SITE (2010) percentage occupied by cattail (Typha) and reed (Phragmites) n= 13 around each nest and in all marsh vegetation of each wetland. Variable All approximations and measurements were made by the Min Max Mean ± SD same person. Water level 8 45 15±12 (cm) III. RESULTS Vegetation density A. Habitat preference in little crake (plant stems per 240 554 385±90 From all five wetlands we have surveyed, we found little square meter) crake breeding populations in only two lakes (Cătina and Typha sp. (%) 0 100 50±25 Sucutard). Between June and August 2010, a total of 36 little Phragmites sp. crake nests were located. (%) 0 100 50±25 The water depth at the nest sites varied between 40 to 91 cm, vegetation density ranged from 321 to 467 plant stems C. Wetlands characteristics and evolution in time per square meter, and the percentage of plant species at the nest site was 100% for cattail (Table 1). Inland wetland ecosystems are not static units but are subject to continuous evolution [4]. The general ecological B. Habitat preference in water rail succession and habitats changes include various stages when We found water rail breeding populations in all five Typha and Schoenoplectus are replaced by Phragmites and wetlands that we studied (Sic, Legii, Cătina, Sucutard and Carex, and the formation of peat above the sediment sets the Pike Lake). Between May and August 2010, we located a stage for the invasion of Salix and Betula [4]. total of 13 water rail nests. Upon surveying historical data [12], we found that all of The depth of the water at the nest site varied from 8 to 45 five wetlands under study are undergoing a sedimentation cm, vegetation density ranged from 240 to 554 plant stems process (Table 3). per square meter, and the percentage of plant species at the At Pike Lake, the vegetation area has increased in time, nest site was from 0 to 100% for cattail and in the same way proportional with the sedimentation process. In 1957, the from red (Table 2). marsh vegetation area was estimated at 17 ha, in 2000 at 27.5 Some of the Water Rail’s nests were found nearby little [12] and in 2008 at 131 ha [7]. Today, at Pike Lake, on the crake nests (within 6 m), in that part of wetlands where the brink of the marsh vegetation, Salix has appeared, as a result water level varied from 40 to 45 cm and where vegetation of a strong sedimentation proces. communities began to be dominated by cattail. In 1970 Legii wetlands was a pond with an water open area of approximately 17 ha, but today, as in the Sic TABLE I LITTLE CRAKE HABITAT CHARACTERISTICS AT THE NEST wetlands case, it is a very large marsh vegetation area [7]. SITE (2010) We can see that in Fizeş Basin, the declining water levels n= 36 correlate with the decreasing percentage of cattail occupation Variable in the marsh vegetation (Figs. 1 and 2). Min Max Mean±SD Water level 40 91 63±12 TABLE III WETLANDS CHARACTERISTICS (cm) Typha Marsh Year Water Water sp./ Vegetation vegeta- level open Phragmi density 321 467 398±46 tion Wetlands (m) area tes sp. (plant stems Water area 2005 (%) percent- per square level (m) (%) meter) age (%) Typha sp 1966 (%) 100 100 100±0 Cătina 4.0 1.6 62 38 70/30 Phragmites sp. 1966 (%) 0 0 0±0 Sucutard 4.0 2.4 9 91 70/30 ~ 1300 lakes Sic and 0.60 100 0 25/75 marshes 1970 Legii 3 1 90 10 20/80 - Ştiucii - 2.3 78 22 20/80 92 IV. DISCUSSION and little crake (Table 2), we observed that their niches are overlapping in terms of water depth and vegetation density A. Little crake is loosing habitats (Fig.