**Important Caves in Turkish Thrace for Bats: Dupnisa Cave System and Koyunbaba Cave**

Serbülent Paksuz

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.68836

#### **Abstract**

Today, caves and some bat populations are declining worldwide because of anthropogenic pressures such as habitat use, tourism, quarrying, and guano mining. The protection of caves is very essential for bat conservation programs because some caves are indispensable and specific living areas for many bat populations. In this chapter, the species composition, colony structure, seasonal population dynamics, roosting habits, and roosting requirements of the bats in Dupnisa Cave System and Koyunbaba Cave in Turkish Thrace are discussed. Dupnisa Cave System and Koyunbaba Cave, which have different roost characteristics and microclimates, are alternative to each other in terms of the season. Therefore, they are inhabited by different bat species for different purposes at different levels according to weather conditions changing throughout the year. Dupnisa Cave System is mainly used by 18 bat species for hibernating, whereas Koyunbaba Cave is mainly used by 11 bat species for breeding and nursing. Due to different roost characteristics and microclimatic conditions, Dupnisa Cave System and Koyunbaba Cave are the most important underground habitats for bat populations in Turkish Thrace. Therefore, the protection of these caves is very important for the future of bat populations in the region.

**Keywords:** bats, caves, conservation, Dupnisa Cave System, Koyunbaba Cave, Turkish Thrace

### **1. Introduction**

This chapter summarizes general information about cave ecosystems and bats. In the first part, the characteristics and importance of caves and bats will be elaborated for interested readers

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

who are not experts in these subjects. In the following sections, geomorphology and biogeography of Turkey and Turkish Thrace are discussed in detail, and the characteristics that make the region important are also underlined. In conclusion of the chapter, more detailed data about Dupnisa Cave System and Koyunbaba Cave in Turkish Thrace will be presented, and the importance of these caves for the future of the bats in the region will be revealed. This chapter presents a summary of related previous studies. The aim is to raise awareness about the protection of bats and caves rather than be a reference for similar topics.

#### **1.1. Cave ecosystems and their characteristics**

In simple terms, cave is defined as an underground hollow that is large enough for a person to enter; however, cave has various definitions in terminology. Caves are formed as a result of the dissolution of carbonated and sulfated rocks with a series of physiochemical processes by underground waters. Caves contain the past and current data of the geological, geomorphological, hydrological, and ecological characteristics of the region where they are located [1]. Caves are not only the underground hollows formed in the rocks but also the unique habitats that host many organisms and natural values. Caves are important ecosystems in terms of both cave-dwelling species, and geological, historical, anthropological, archaeological, ecological, and cultural values.

Caves are very specific and susceptible ecosystems, because they have some extreme features that force life such as darkness, low temperature, high humidity, and limited nutrients [2–4]. Because of their darkness, caves are devoid of plants, which are the main producers of the food chain. For this reason, all the organic materials are brought from the outside into the cave in various ways. The main factors that provide nutrient entry into the caves are the air flows and the water currents in the caves. Besides these, guano, the main energy source in the growth of many organisms, is the most important nutrient in caves [5]. Lack of light, low temperature, high humidity, and the restriction of nutrients can be seen as important limiting factors in many caves [3, 4]. In the caves, living organisms are resistant or adapted to the scarcity of nutrients and other limiting factors. The essential condition for organisms to survive in the cave is energy saving. For this reason, the cave organisms are as small as possible and they move as little as possible.

The most important difference between underground and terrestrial habitats is the stable environmental conditions of caves. Unlike terrestrial conditions, caves have an almost constant temperature and humidity throughout the year. All these differences and characteristics make cave habitats unique and very sensitive. Any changes in the conditions of the cave ecosystems threaten the lives of the cave inhabitants. Despite challenging living conditions such as darkness and limited nutrient sources, caves accommodate many species [3, 4]. Because of these negative conditions in the cave, the cave dwellers have developed various ways of adaptations to survive. For example, the sense of sight of organisms adapted to life in caves has either weakened or completely disappeared in the evolutionary process. On the other hand, most of these species have developed their antennas longer than their relatives outside. Similarly, some species that adapted to the cave life usually appear white or transparent because they lack pigment.

Caves are initially creepy, but the mystery of the darkness and the past in caves is the most important features that attract people into caves. And also, in the caves formed as a result of a very slow and long process, stalactites, stalagmites, and travertines come in various formations, which attract people visually. In addition, underground waters, rivers, and lakes within caves are another beauty. So, it is possible to see that cave tourism, which is called as alternative tourism, has improved all over the world. The visual, sportive, religious, historical, and cultural characteristics of the caves provide a potential for tourism. However, it is also known that caves are used for different purposes such as shelter, barn, and storage. For this reason, it is inevitable that underground habitats, which are natural habitats of organisms, are damaged by human pressures over time.

Underground habitats around the world are under constant threat due to human pressures such as cave tourism, treasure hunting, guano mining, stone quarries, and water dams. The use of caves by humans can cause significant harmful effects on caves [6–8]. It should not be forgotten that these natural values, gradually formed in millions of years, will not come back again in a short time. For this reason, the identification and investigation of important cave habitats are essential for the future of these habitats and organisms living there.

#### **1.2. Bats and their characteristics**

who are not experts in these subjects. In the following sections, geomorphology and biogeography of Turkey and Turkish Thrace are discussed in detail, and the characteristics that make the region important are also underlined. In conclusion of the chapter, more detailed data about Dupnisa Cave System and Koyunbaba Cave in Turkish Thrace will be presented, and the importance of these caves for the future of the bats in the region will be revealed. This chapter presents a summary of related previous studies. The aim is to raise awareness about the protec-

In simple terms, cave is defined as an underground hollow that is large enough for a person to enter; however, cave has various definitions in terminology. Caves are formed as a result of the dissolution of carbonated and sulfated rocks with a series of physiochemical processes by underground waters. Caves contain the past and current data of the geological, geomorphological, hydrological, and ecological characteristics of the region where they are located [1]. Caves are not only the underground hollows formed in the rocks but also the unique habitats that host many organisms and natural values. Caves are important ecosystems in terms of both cave-dwelling species, and geological, historical, anthropological, archaeological, eco-

Caves are very specific and susceptible ecosystems, because they have some extreme features that force life such as darkness, low temperature, high humidity, and limited nutrients [2–4]. Because of their darkness, caves are devoid of plants, which are the main producers of the food chain. For this reason, all the organic materials are brought from the outside into the cave in various ways. The main factors that provide nutrient entry into the caves are the air flows and the water currents in the caves. Besides these, guano, the main energy source in the growth of many organisms, is the most important nutrient in caves [5]. Lack of light, low temperature, high humidity, and the restriction of nutrients can be seen as important limiting factors in many caves [3, 4]. In the caves, living organisms are resistant or adapted to the scarcity of nutrients and other limiting factors. The essential condition for organisms to survive in the cave is energy saving. For this reason, the cave organisms are as small as possible and

The most important difference between underground and terrestrial habitats is the stable environmental conditions of caves. Unlike terrestrial conditions, caves have an almost constant temperature and humidity throughout the year. All these differences and characteristics make cave habitats unique and very sensitive. Any changes in the conditions of the cave ecosystems threaten the lives of the cave inhabitants. Despite challenging living conditions such as darkness and limited nutrient sources, caves accommodate many species [3, 4]. Because of these negative conditions in the cave, the cave dwellers have developed various ways of adaptations to survive. For example, the sense of sight of organisms adapted to life in caves has either weakened or completely disappeared in the evolutionary process. On the other hand, most of these species have developed their antennas longer than their relatives outside. Similarly, some species that adapted to the cave life usually appear white or transparent because they lack pigment.

tion of bats and caves rather than be a reference for similar topics.

**1.1. Cave ecosystems and their characteristics**

logical, and cultural values.

78 Cave Investigation

they move as little as possible.

Bats (Chiroptera) are among the most diverse and widely distributed groups of mammals and can be found in most continents. Bats consist of greater than 1300 species worldwide and comprise approximately one quarter of mammalian species richness [9–11]. The order Chiroptera is subdivided into the Megachiroptera and the Microchiroptera. The Megachiroptera is represented by only one family, whereas the Microchiroptera comprise 17 families. Megabats are also called as fruit bats. Fruit bats mostly roost in trees and shrubs. Megabats are frugivorous and nectarivorous, and they eat fruit or lick nectar from flowers. Microbats are called as insectivorous, and they mostly feed on insects, and use echolocation. Insectivorous bats use a wide variety of roosts such as caves, trees, and manmade structures.

Bats are the only flying mammals and they have a wide range of feeding and roosting habits, social behaviors, and reproductive strategies. Flying ability made bats become one of the most common groups of mammals [6]. Most of bat species use echolocation to navigate and forage. Echolocation allowing bats to see their surroundings by sound is actually an adaptation. Bats emit calls out to the environment through their nostrils and mouth, and then they find their direction by listening to the echoes of the calls returning from the objects around them. Thus, bats get information about the location, position, and shape of objects in the surroundings by processing these echoes [12, 13]. When food quantity decreases, bats have to make a choice: to hibernate or to migrate. Hibernation involves a reduction in metabolic rate that allows bats to survive for a long time without food [14]. Many species of bats migrate between summer and winter roosts. Some migrations are made to reach for more abundant food sources in warmer locations, while others are made to obtain roosts that have optimal microclimate for hibernating in winter or raising offspring in summer [14, 15].

Bats have acquired a wide variety of characteristics in parallel with the lifestyle they are adapted. Although the patterns of feeding, roosting, and reproduction of the bats differ between species, some basic adaptations are similar. Most bat species are nocturnal, and they forage during the nights. Bats feed with a wide variety of foods such as insect, fruit, flower nectar, small vertebrate, and blood [12, 15]. In the daylight, bats pass into torpor in roosts such as foliage, caves, hollows of trees, rock crevices, and various manmade structures. The most prominent predators of bats are owls, hawks, snakes, raccoons, and martens [15]. Female bats have some strategies that they can control the timing of their pregnancy to give birth at an appropriate time [13]. Females generally give birth to one offspring every year, and they nurse their young until they get mature to feed on their own [15].

Bats that play a key role in many ecosystems are an important group of mammals with species diversity, abundance, and distribution all over the world. Bats have important ecological roles that are critical for human and ecosystem health, including the pollination and dispersal of many plants, and the control of insects [16, 17]. Bats are primary predators of insects that are harmful for human health and agriculture. Thus, bats play an important role in human health and biological pest control by balancing harmful insect and microorganism populations [15]. Guano mined from caves is provided by bats and used as a natural fertilizer on agricultural crops. Guano is a primary source of nutrition that allows the development of a great diversity of organisms such as arthropod, fungi, bacteria, and lichen.

Bats are one of the most sensitive mammal groups to varying weather conditions with their peculiarities in physiology, thermoregulation, and life cycle. Bats prefer different roosts depending on the season and spend more than half of their lives in roost. Most species of bats have specific requirements in terms of roost conditions such as microclimate and environmental stability [18]. Roosts protect bats from bad weather conditions and their predators, so roost selection is essential to sustain the life of the bats [13]. Therefore, the presence of suitable roost is an important factor affecting the social structure and the distribution of bats [18–20]. The identification of these roosts is essential for the protection of bats. Bats have been known as cave dwellers for a long time, because caves that provide stable environmental conditions and protection throughout the year are pretty suitable roosts for bats. All over the world, caves and mines are used as shelter by large bat populations, but particularly sensitive species are highly dependent on only a few of these underground shelters [9, 18, 21]. However, most caves are used only by a small number of bats. Only a few caves provide convenient conditions to host thousands of bats, especially during hibernating and breeding periods. These caves are vital to bat populations [9, 18, 20, 22].

Microclimatic conditions are often particularly important for habitat quality of bats [23]. Therefore, the seasonal use of roosts by bats is profoundly associated with its microclimatic conditions and these conditions form the assembling patterns of bats. The particular roost requirements of bat species restrict the permanent shelters that are used by bats. Thus, the environmental stability and protection provided by caves make them highly suitable roost for bats throughout the year. Most bat species make use of caves as roost for various purposes during some phases of their annual cycle [22].

Microclimatic requirements of bats show seasonal variations according to their annual life cycle. Therefore, the availability of a cave by bats is increased by providing alternative microclimatic conditions compared to season. Caves may serve as one of the most adequate roosting sites for bats because of the relatively stable microclimatic characteristics. Therefore, natural caves and artificial underground sites are widely used as roosting sites by bats and may be occupied by large breeding and/or hibernating populations [9]. The distribution and availability of suitable roosting sites is a limited resource for some cave-dwelling bat species [20]. Besides, cave-dwelling bats are mostly threatened by visitors and human activities.

The distribution areas of animals depend on their biological requirements and environmental conditions. Because of the variety of such conditions, the caves, which are potential roosts for bats, can serve as a good model for studying the relationship between the regional settlement and the structure of the environment [24]. Bats have to find special periodic roosts according to the requirements of hibernation or breeding, so knowing the roosting requirements of bats is vital for conservation and management works. Identifying and surveying these sites will help to understand the habitat requirements of species [25].

Bats form the largest mammalian assemblages on earth, and one place may be a shelter for a significant portion of the total populations of some species [26]. Such places have a great importance for bats and may be limiting for their population size and distribution. Most bat species rely on underground shelters to maintain their lives. Cave disturbance and destruction is one of the biggest problems that cause the decline of bat populations all over the world, so the identification and protection of such important sites has vital importance for the future of bats [8].

#### **1.3. Biogeography and geomorphology of Turkey**

between species, some basic adaptations are similar. Most bat species are nocturnal, and they forage during the nights. Bats feed with a wide variety of foods such as insect, fruit, flower nectar, small vertebrate, and blood [12, 15]. In the daylight, bats pass into torpor in roosts such as foliage, caves, hollows of trees, rock crevices, and various manmade structures. The most prominent predators of bats are owls, hawks, snakes, raccoons, and martens [15]. Female bats have some strategies that they can control the timing of their pregnancy to give birth at an appropriate time [13]. Females generally give birth to one offspring every year, and they

Bats that play a key role in many ecosystems are an important group of mammals with species diversity, abundance, and distribution all over the world. Bats have important ecological roles that are critical for human and ecosystem health, including the pollination and dispersal of many plants, and the control of insects [16, 17]. Bats are primary predators of insects that are harmful for human health and agriculture. Thus, bats play an important role in human health and biological pest control by balancing harmful insect and microorganism populations [15]. Guano mined from caves is provided by bats and used as a natural fertilizer on agricultural crops. Guano is a primary source of nutrition that allows the development of a great diversity of organisms such as arthropod, fungi,

Bats are one of the most sensitive mammal groups to varying weather conditions with their peculiarities in physiology, thermoregulation, and life cycle. Bats prefer different roosts depending on the season and spend more than half of their lives in roost. Most species of bats have specific requirements in terms of roost conditions such as microclimate and environmental stability [18]. Roosts protect bats from bad weather conditions and their predators, so roost selection is essential to sustain the life of the bats [13]. Therefore, the presence of suitable roost is an important factor affecting the social structure and the distribution of bats [18–20]. The identification of these roosts is essential for the protection of bats. Bats have been known as cave dwellers for a long time, because caves that provide stable environmental conditions and protection throughout the year are pretty suitable roosts for bats. All over the world, caves and mines are used as shelter by large bat populations, but particularly sensitive species are highly dependent on only a few of these underground shelters [9, 18, 21]. However, most caves are used only by a small number of bats. Only a few caves provide convenient conditions to host thousands of bats, especially during hibernating and breeding periods. These

Microclimatic conditions are often particularly important for habitat quality of bats [23]. Therefore, the seasonal use of roosts by bats is profoundly associated with its microclimatic conditions and these conditions form the assembling patterns of bats. The particular roost requirements of bat species restrict the permanent shelters that are used by bats. Thus, the environmental stability and protection provided by caves make them highly suitable roost for bats throughout the year. Most bat species make use of caves as roost for various purposes

nurse their young until they get mature to feed on their own [15].

bacteria, and lichen.

80 Cave Investigation

caves are vital to bat populations [9, 18, 20, 22].

during some phases of their annual cycle [22].

When compared to the regional countries, Turkey has a special biogeography due to its large surface area, different geomorphologic structure, different climatic conditions, and transition position between the continents [27]. As a result of these features, Turkey has a rich biodiversity and a variety of ecosystems that almost a continent can have. The geomorphological structure of Turkey is one of the main factors in having various biogeographic areas [27].

The soluble karstic rocks such as limestone, gypsum, and dolomite, which are suitable for cave formation, constitute approximately 40% of Turkey's surface area [28]. One of the most important formations in the karstic areas of Turkey is caves. Because of the insufficiency of cave explorations, not all of the caves in Turkey have yet been examined; it is not possible to give a definite figure about the number of caves in our country. However, it is estimated that more than 20,000 caves can be found in Turkey according to the size of the area covered by the soluble rocks and the ratio of the number of caves detected in these areas [28]. However, many of the caves in Turkey are still not identified. In parallel, research on caves in Turkey is extremely inadequate. The research carried out until now is mostly focused on the caves in the touristic areas. Approximately 3000 of these caves were surveyed by caving associations, clubs, communities, and organizations. Until today, 31 caves in Turkey have been opened as tourist attractions [29].

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

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 in the region [30].

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

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.

detail by the author based on regular and long-term monitoring (**Figure 1**) [35–38]. In recent years, many studies have been conducted throughout Turkey to determine other underground habitats that are important for bat populations. These studies provide important contributions to the identification and conservation of the bat populations and roosts in Turkey [39, 40].

Due to its location and different climatic zones, Turkey has become a homeland and shelter for many species affected by geological and climatic changes in the past. For this reason, Turkey, which has a rich biodiversity, is also very rich in terms of bat species. Turkey is the country with the highest bat diversity in the region with 39 species identified so far. In Turkish Thrace, 27 of these species have been recorded. Dupnisa Cave System, Koyunbaba Cave, and Kocakuyu Cave are the most important shelters for bats in the Thrace region of Turkey [32–38].

Besides the lack of suitable shelters, today's rapidly growing urbanization, population growth, and the increased interest of humans intended for nature are causing damage and gradual decline of natural habitats of bats, and thus bat populations are at risk of extinction. Cave-dwelling bats are mostly threatened by visitors and human activities. Treasure hunting, quarrying, and cave tourism are the main threats to caves in Turkish Thrace. Knowing and protecting of roosts are essential to bat conservation. The use of caves by bats is shaped by microclimatic, morphological, and ecological conditions provided by the caves, because species have specific requirements for roosts in terms of shelter. Roost selection of bats differs in particular parts of caves and changes according to their annual life cycle. Therefore, knowledge about roost requirements and roost switching of the bat species in Turkish Thrace is required to any plan of the protection of the bats.
