**2. Methodology and study area**

**1.4. Biogeography and geomorphology of Turkish Thrace**

altitudes of 70 and 345 m, respectively [30, 31].

in the region [30].

82 Cave Investigation

Thrace is a geographic region located in southeastern Europe within the territories of Greece, Bulgaria, and Turkey. Thrace lies in the northeastern Greece, the southeastern Bulgaria, and the European part of Turkey (**Figure 1**). Turkish Thrace, which constitutes about 3% of Turkey's surface, is not very high (average altitude of 180 m) and only 15% of the region is covered by forest in north and south. When evaluated in terms of geological, geographical, and tectonic features, it is seen that the Thrace region is different from the other regions of Turkey. Karst formation in Turkish Thrace is characterized by Eocene limestone, but a few caves developed within the marbles of the Paleozoic metamorphic basement, which is limited

Thrace is one of the major biogeographic zones in Turkey and, due to its karst formation, more than 50 caves have been formed in the region. Most of these caves, which form horizontally, are fossil-typed caves that have completed development. The caves in Turkish Thrace are concentrated at elevations between 150 and 200 m in Yıldız Mountains. The two longest caves explored were İkigöz Cave (4816 m) and Dupnisa Cave System (2720 m) in length with

Despite the presence of thousands of caves in Turkey, there are few studies of the cave fauna, and most are old and based on the limited sampling. However, in recent years, the caves in Turkish Thrace have been slightly more surveyed in terms of the bats. Bilgin [32] has examined some of the caves in the region and provided information on the summer population sizes and habitat preferences of the bat species. Furman and Özgül [33, 34] have investigated the population sizes of bat species in many caves in the region and also stated that they should be protected by identifying important underground shelters in the region. In particular, two caves in the region, Dupnisa Cave System and Koyunbaba Cave, have been investigated in

**Figure 1.** The location map of Thrace, and the positions of Dupnisa Cave System and Koyunbaba Cave in Turkish Thrace.

In this study, Dupnisa Cave System and Koyunbaba Cave in Turkish Thrace were investigated based on a long-term monitoring. The data given in this chapter belong to the years 2002–2010 for Dupnisa Cave System and 2007–2008 for Koyunbaba Cave. The roosts used by bats in both the caves were determined. In each survey, the species composition, colony structure, seasonal population numbers, and roosting habits of the bats were recorded. Roost temperature and humidity were regularly measured in each survey. Collected data were evaluated in two periods as winter/hibernation (November–March) and summer/nursery (April–October). Species identifications were done by following the identification keys [41]. Small colonies were counted directly and large colonies were counted using photographs. Also, some of these data have been previously presented by the author at congresses and articles [36, 38, 42].

#### **2.1. Dupnisa Cave System**

Dupnisa Cave System is located south of Sarpdere Village (Kırklareli) in Thrace, the European part of Turkey (**Figure 1**). The cave system lies in the forested Yıldız (Strandja) Mountains. Dupnisa Cave System is the second largest cave in Thrace region with a total length of 2720 m long. This cave system, which developed as a result of the disintegration of the Pliocene relief system in the upper part of the Yıldız Mountains with the Quaternary rivers, has the polycyclic development feature [31]. The cave system, which has four entrances, has developed horizontally and its formation process still continues. Dupnisa Cave System is regarded as a cave system because it is formed by two floors and three interconnected caves. These caves have different features. In this system, the active main gallery through which an underground stream flows is called Sulu Cave, while the totally fossilized ones above are called Kuru Cave and Kız Cave (**Figure 2**) [31].

Sulu Cave has the longest gallery of these caves with a length of 1977 m, and has only one entrance and one corridor. The height and width of this corridor are up to 40 and 15 m, respectively, and there is a very large hall of 125 m long, 80 m high and 35 m wide in this corridor. Kuru Cave, with a total length of 480 m, has two entrances and two corridors. In addition, a large hall was formed at the junction of these two corridors. Kuru Cave is connected with Sulu Cave by a narrow corridor. Kız Cave, 263 m in length, has one entrance and a small hall after the entrance. Kız Cave, which is covered with a thick fossil layer mixed with large blocks, gravel, and sand, is connected to Sulu Cave below at two points (**Figure 2**) [31].

Dupnisa Cave System is the first cave in the Thrace region that was opened to visitors in July 2003. This cave is also the first cave in Turkey to be opened to visitors with a program and gate construction according to the seasonal use of the cave by bats based on long-termmonitoring program [38]. Tourist circuits were constructed with the first 200 m of Sulu Cave and the first 230 m of Kuru Cave. However, Kız Cave is closed to visitors (**Figure 2**). The cave system has been visited by about 35,000 visitors each year after it was opened to visitors. The cave system has four entrances and two of these entrances, which are located on the tourist area, are closed to control human entry (**Figure 3**). Gates are constructed with a design of the horizontal angle iron bars that have 200-mm spacing between bars. The other entrances of the cave system, outside of the tourist area, where human entry is difficult, have been left to the natural state to minimize the negative effects of the two doors on the bats (**Figure 3**) [38].

**Figure 2.** Dupnisa Cave System: the location of the three main caves, the areas open to tourists, and the gated and ungated entrances [38]. Adapted from Ref. [31].

Important Caves in Turkish Thrace for Bats: Dupnisa Cave System and Koyunbaba Cave http://dx.doi.org/10.5772/intechopen.68836 85

**Figure 3.** The gated entrances of Sulu Cave (a) and Kuru Cave (b), used to control the entry of tourists. The ungated entrances of Kuru Cave (c) and Kız Cave (d), remained to minimize the negative effects of the gates on the bats.

#### **2.2. Koyunbaba Cave**

polycyclic development feature [31]. The cave system, which has four entrances, has developed horizontally and its formation process still continues. Dupnisa Cave System is regarded as a cave system because it is formed by two floors and three interconnected caves. These caves have different features. In this system, the active main gallery through which an underground stream flows is called Sulu Cave, while the totally fossilized ones above are called

Sulu Cave has the longest gallery of these caves with a length of 1977 m, and has only one entrance and one corridor. The height and width of this corridor are up to 40 and 15 m, respectively, and there is a very large hall of 125 m long, 80 m high and 35 m wide in this corridor. Kuru Cave, with a total length of 480 m, has two entrances and two corridors. In addition, a large hall was formed at the junction of these two corridors. Kuru Cave is connected with Sulu Cave by a narrow corridor. Kız Cave, 263 m in length, has one entrance and a small hall after the entrance. Kız Cave, which is covered with a thick fossil layer mixed with large blocks, gravel, and sand, is connected to Sulu Cave below at two points

Dupnisa Cave System is the first cave in the Thrace region that was opened to visitors in July 2003. This cave is also the first cave in Turkey to be opened to visitors with a program and gate construction according to the seasonal use of the cave by bats based on long-termmonitoring program [38]. Tourist circuits were constructed with the first 200 m of Sulu Cave and the first 230 m of Kuru Cave. However, Kız Cave is closed to visitors (**Figure 2**). The cave system has been visited by about 35,000 visitors each year after it was opened to visitors. The cave system has four entrances and two of these entrances, which are located on the tourist area, are closed to control human entry (**Figure 3**). Gates are constructed with a design of the horizontal angle iron bars that have 200-mm spacing between bars. The other entrances of the cave system, outside of the tourist area, where human entry is difficult, have been left to the natural state to minimize the negative effects of the two doors

**Figure 2.** Dupnisa Cave System: the location of the three main caves, the areas open to tourists, and the gated and

Kuru Cave and Kız Cave (**Figure 2**) [31].

(**Figure 2**) [31].

84 Cave Investigation

on the bats (**Figure 3**) [38].

ungated entrances [38]. Adapted from Ref. [31].

Koyunbaba Cave is located in the province of Kırklareli in Thrace of Turkey at 155 m altitude (**Figure 1**). Its length is 532 m, horizontally developed, and a fossil cave [31]. Depending on its development, the cave consists of different parts with various characteristics. There are seven stations used as roost by the bats in Koyunbaba Cave. These stations have different characteristics in terms of roost type, height, and microclimate (**Figure 4**).

Koyunbaba Cave developed on a prominent northwest-southeast direction fault line on the Eocene limestone. The fractured structure of the limestone resulted in the formation of many cavities and recess ledges in the cave. The cave initially developed in the northwest-southeast direction and takes the northeast-southwest direction from the middle section. At the intersection of these two sections, a large subsidence hall with a width of 50 × 60 m and a ceiling height of 30 m has developed (**Figure 4**). The formation of dripstone in Koyunbaba Cave, which has its base covered with a thick fossil layer consisting of soil, gravel, rubble block, and guano, is almost inexistent [31].

Koyunbaba Cave has three entrances, which are linked with different characteristics. The main entrance is the largest one. It is horizontally formed and its entry is very easy. Koyunbaba

**Figure 4.** Koyunbaba Cave: the location of the seasonal roosts used by the bats, the three entrances of the cave. Adapted from Ref. [31].

Cave is closed to visitors, but this area of the cave is used by local people as an animal shelter during the summer. The second and third entrances of the cave are vertical. Because they are quite dangerous, these entrances cannot be used by local people (**Figure 5**). The cave is located in a relatively flat area consisting of farmland and pastures. This area is outside the Strandja Forest tree line. There are important water resources (Teke stream and Kayalı dam) around the cave.

**Figure 5.** The three entrances of Koyunbaba Cave: the main entrance (a), the second entrance (b), and the third entrance (c).
