TOURISM IMPACT ON NESTING HABITAT OF LOGGERHEAD SEA TURTLE IN CRETE, GREECE

Transcription

1 TOURISM IMPACT ON NESTING HABITAT OF LOGGERHEAD SEA TURTLE IN CRETE, GREECE Paula Lima February 2008 International Institute for Geo-Information Science and Earth Observation,

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3 TOURISM IMPACT ON NESTING HABITAT OF LOGGERHEAD SEA TURTLE IN CRETE, GREECE by Paula Lima Thesis submitted to the International Institute for Geo-information Science and Earth Observation in partial fulfilment of the requirements for the degree of Master of Science in Geo-information Science and Earth Observation, Specialisation: Environmental System Analysis and Management Thesis Assessment Board Chairman: Prof. Jan de Leeuw External Examiner: Dr. Neftali Sillero Internal Examiner: Dra. Liza Groenendijk First Supervisor: Dr. Bert Toxopeus Second supervisor: Dr. Mike McCall International Institute for Geo-Information Science and Earth Observation, Enschede, The Netherlands

4 Disclaimer This document describes work undertaken as part of a programme of study at the International Institute for Geo-information Science and Earth Observation. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the institute.

5 SEA TURTLES CAN NOT REPRODUCE WITHOUT NESTING BEACHES (DEMETROPOULOS, 2000) i

6 ABSTRACT Two of the seven species of sea turtles breed in the Mediterranean, the Loggerhead Turtle (Caretta caretta) and the Green Turtle (Chelonia mydas). Both had been abundant in the past, but now as a consequence of different human activities such as urban and tourism development as well as fisheries, the population size and location have been seriously affected. As a result, the Red List of the World Conservation Union (IUCN) classified these species as endangered in The base of turtle conservation is the protection and management of nesting beaches, because in particular female turtles do not breed on any beach. They return faithfully to their natal beaches which previous generations had chosen as suitable. Nowadays tourism development is considered as the main threat for nesting areas, because unfortunately the same beaches seen as desirable by turtles for breeding are also popular for beach holiday destinations. In order to contribute to the understanding of human and wildlife interactions, this research focuses on the analysis of the potential impacts of tourism development on the Loggerhead turtle nesting habitat along the beach of Rethymno in Crete. This research was divided in three parts. The first was the identification of the relationship between loggerhead nesting density and tourism development at two different scales. Initially, it evaluated how the tourism industry had been developing in Crete over the years and determined if there was any association with the decrease in nesting populations. Secondly, the relationship between tourism and nesting density at beach scale was done through the spatial and statistical analysis of tourism infrastructure (e.g. hotels, bars, restaurants, shops) and the location of the nests. This analysis helped to determine the contribution of these tourism variables on the degradation of the nesting beaches. Once the relationship between tourism development and nesting density was recognized, the second step was the identification of suitable areas for loggerhead nesting taking into consideration the tourism infrastructure variables. In order to achieve this objective an SMCE technique was used. Finally, in order to illustrate and quantify the diminishing of the nesting areas in Rethymno over the past decades three more suitability maps were elaborated using satellite imagery from past years (1945, 1997, and 2004). As a result it was shown that nesting female turtles avoid the areas with high concentration of tourism infrastructure. Additionally according to the SMCE the areas considered as highly suitable for sea turtle nesting in Rethymno have been decreased by 50% in area during the last 60 years. These results show that there is a clear degradation of the nesting beaches caused by the success of tourism industry. Once an appropriate relationship is well establish between wildlife preferred habitats and anthropogenic disturbance factors, the SMCE could become a powerful tool in the generation of new scenarios and the exploration of new management options for the protection of nesting beaches against the urban and tourism development along the beaches. ii

7 ACKNOWLEDGMENTS I would like to extend my sincere appreciation to all people, who supported me with their valuable knowledge, time and supports to make this research possible. First and foremost, my special gratitude goes to Dr. Bert Toxopeus, my first supervisor, for their excellent guidance and constructive comments. I would like to acknowledge his effort in shaping this work, and also for his words of encouragement during all the process. I am also grateful to my second supervisor Dr. Mike McCall for all his comments that most of the time clarified me the way. I am in debt for all his support and words of encouragement. Dr. Jan de Leeuw, Dr. David Rossitter, and Dr. Henk Kloosterman, for their opportune comments and suggestions during my research. I am also thankful to the staff of the University of Crete, in particular to Dr. Petros Lymberakis, and Alexandra Cavadia for their extraordinary support during my fieldwork in Greece. I have no words to thank to all my international friends for their support and especially for their sincere friendship. But the only thing that I know is that I will never forget them. Last but not least, my everlasting gratitude goes to my family for their unconditional support and LOVE. iii

8 This thesis is an outcome of the BIOFRAG ITC internal research project in collaboration among: -International Institute for Geo-Information Science and Earth Observation ITC, Enschede, -University of Crete, Greece -Museum of Natural History, Heraklion, Crete, Greece -Sea Turtle Protection Society of Greece ARCHELON, Greece -Forestry Department of Heraklion and Rethymno and Hellenic Military Service -HNTO Heraklion Netherlands Special thanks to Dr. Petros Lymberakis, Alexandra Cavadia, and Manolis Nikolakakis. Without their cooperation and willingness to share data and assistance in the field this research would not have been possible. Many thanks are in order for ARCHELON volunteers in the island of Crete specially Simon Proctor. iv

9 TABLE OF CONTENTS 1 INTRODUCTION BACKGROUND Endangered Sea Turtles in the Mediterranean Impact of the tourism development Suitable nesting beaches threatened by tourism development RESEARCH PROBLEM RESEARCH OBJECTIVE General objective Specific objectives RESEARCH QUESTIONS HYPOTHESES RESEARCH BACKGROUND About loggerhead sea turtle (Caretta caretta) Nesting behavior Egg development Hatching and behavior of baby sea turtles Maturity Navigation and migration Facing the hazards of humankind Limitations of the tourism impact analysis on sea turtle breeding Environmental requirements vs. human disturbances along nesting beaches MATERIALS AND METHODS STUDY AREA Tourism development in Crete Nesting beaches in Crete Rethymno: The main host beach of sea turtles in Crete RESEARCH METHODS Fieldwork preparation Definition of tourism variables In Situ data collection Nesting density and tourism development in Rethymno Past and future situation Spatial distribution of sea turtle nests and tourism infrastructures at beach scale Defining the relationship between nest density and tourism infrastructure Spatial Multi- Criteria Evaluation: Nesting suitability for Sea Turtles RESULTS ANALYSIS OF NESTING DENSITY AND TOURISM DEVELOPMENT IN RETHYMNO PREFECTURE v

10 3.1.1 Seasonal Conflict between tourists and sea turtles Nesting density Behavior over time Tourism development Behavior over time Predictions for the nesting density and tourism development Summary ANALYSIS OF THE RELATIONSHIP BETWEEN NESTING DENSITY AND TOURISM DEVELOPMENT AT BEACH SCALE Analysis of each tourism infrastructure and nest density per transect Spatial distribution analysis of tourism infrastructure and nests Analysis of the correlation between nesting density and tourism infrastructure Spearman rank order correlation coefficient Fisher exact test Summary HABITAT SUITABILITY MODEL FOR LOGGERHEAD TURTLE Structuring the suitability map for sea turtle nesting habitat Standardization Weighting Suitability assessment Identification of the potential nesting sites Summary MULTI-TEMPORAL ANALYSIS OF THE NESTING SUITABILITY HABITAT (1945, 1997, 2004, 2007) Summary CONCLUSIONS AND RECOMMENDATIONS CONCLUSIONS RECOMMENDATIONS DISCUSSION HOW DOES TOURISM DEVELOPMENT IMPACT SEA TURTLES IN CRETE TOURISM INFRASTRUCTURE AS AN INDICATOR FOR THE EVALUATION OF NESTING SUITABILITY SEA TURTLE NESTING HABITAT SUITABILITY MODEL LIMITATIONS OF THE RESEARCH REFERENCES APPENDIX vi

11 LIST OF FIGURES Figure 1.1 Human and non human impacts on sea turtle cycle life...8 Figure 2.1 Study area...13 Figure 2.2 Diagram of the research method...13 Figure 2.3 Tourism variables that causes disturbances on the quite nesting beaches...14 Figure 2.4 Nest cage used by ARCHELON to protect the nest against sand compactation...16 Figure 2.5 Nest fence used by ARCHELON to protect nest and avoid disorientation of hatchlings Figure 2.6 Flowchart for the MCE design phase...20 Figure 2.7 Hierarchical structure of the MCE...20 Figure 3.1 Monthly tourist arrivals to Rethymno and the sea turtles breeding periods (2003)...23 Figure 3.2 Number of nests in Rethymno ( ) and the projection line for the next years...24 Figure 3.3 Arrivals by charter flights to Crete ( ) and the projection for the next years...25 Figure 3.4 Number of hotels in Rethymno ( ) and the projection line for the next years Figure 3.5 Number of bedrooms in Rethymno ( ) and the projection line for the next years. 26 Figure 3.6 Number of bedplaces in Rethymno ( ) and the projection line for the next years. 26 Figure 3.7 Number of stayovernights in Rethymno ( ) and the projection line for the next years Figure 3.8 Scatterplot between tourism parameters and nest density over the time...27 Figure 3.9 Nesting and tourism behaviour ( )...29 Figure 3.10 Number of nests and hotels per transect...30 Figure 3.11 Percentage of nests in each transect class defined by hotel density...30 Figure 3.13 Number of nests and restaurants per transect...30 Figure 3.14 Percentage of nests in each transect class defined by restaurant density...30 Figure 3.15 Number of nests and shops per transect...31 Figure 3.16 Percentage of nests in each transect class defined by shop density...31 Figure 3.17 Number of nests and bars per transect...31 Figure 3.18 Percentage of nests in each transect class defined by bar density...31 Figure 3.19 Number of nests and houses per transect...32 Figure 3.20 Percentage of nests in each transect class defined by house density...32 Figure 3.21 Number of nests and parking lots per transect Figure 3.22 Percentage of nests in each transect class defined by parking lot density...32 Figure 3.23 Number of nests and recreational areas per transect...33 Figure 3.24 Percentage of nests in each transect class defined by recreational area density...33 Figure 3.25 Number of nests and sunbeds per transect...33 Figure 3.26 Percentage of nests in each transect class defined by sunbeds density...33 Figure 3.27 Transects with the highest concentration of nests and tourism infrastructures along the beach...34 Figure 3.28 Areas with high density of nests and tourism infrastructures using KDE...34 Figure 3.29 Percentage of vegetated and non vegetated areas on tourism and nesting zones...35 vii

12 Figure 3.30 Criteria Tree used in the analysis of suitable nesting areas for C. Caretta...40 Figure 3.31 Histogram with the suitable classes used in the MCE...41 Figure 3.32 Potential Suitable area for sea turtle nesting (site 1)...43 Figure 3.33 Potential suitable area for sea turtle nesting (site 2)...44 Figure 3.34 Potential suitable area for sea turtle nesting (site3)...45 Figure 3.35 Nesting suitability areas (ha) for 1945, 1997, 2004, Figure 3.36 Changes in the suitable nesting areas since viii

13 LIST OF TABLES Table 1.1 Human impacts on the sea turtle population...7 Table 2.1 Nesting density in Crete (1990, 2002, 2003)...12 Table 2.2 Description of the tourism infrastructure variables...15 Table 2.3 Classification of the transects based on the infrastructure density...18 Table 2.4 Classification of the transects based on the sunbeds density...18 Table 2.5 Structure of the 2x2 contingency table for the analysis of the relationship between nests and tourism infrastructure...19 Table 3.1 Occupancy rates in Crete Prefectures ( )...27 Table 3.2 Pearson correlation between tourism parameters and number of nests...28 Table 3.3 Prediction of tourism parameters and nesting density in Crete for the next years...28 Table 3.4 Tourism infrastructure and nests collected during the fieldwork in Table 3.5 Vegetated and non vegetated areas for each delimited zone...35 Table 3.6 R-square of the linear relationship between nest and tourism infrastructure at beach scale...36 Table 3.7 Spearman Rank Order Correlation Coefficient (1 Tailed)...36 Table 3.8 Results of the Fisher Exact Test for 2x2 tables...37 Table 3.9 Order of importance of each criterion used in the MCE...40 Table 3.10 Area (Ha) according each suitability class...41 Table 3.11 Area (Ha), number of nests and nesting density per potential nesting sites...42 Table 3.12 Nesting suitability areas in 1945, 1997, 2004 and ix

14 ACRONYM LIST IUCN CITES CMS WTO SMCE TSD SWOT GNTO KDE USFWS World Conservation Union Convention on International Trade in Endangered Species of Wild Fauna and Flora The Convention on the Conservation of Migratory Species of Wild Animals World Tourism Organization Spatial Multi-Criteria Evaluation Temperature-Dependent Sex Determined The State of the World s Sea Turtles Greek National Tourism Organization Kernel Density Estimation US Fish and Wildlife Service x

15 TOURISM IMPACT ON THE SEA TURTLE 1 Introduction 1.1 Background Endangered Sea Turtles in the Mediterranean In the World two of the seven species of sea turtles breed in the Mediterranean, the Loggerhead Turtle (Caretta caretta) and the Green Turtle (Chelonia mydas). Both had been abundant in the past, but now as a consequence of different human activities such as tourism development, fisheries, water pollution and also the presence of some predators like foxes and dogs, the population density has been seriously affected. As a result, the Red List of the World Conservation Union (IUCN) classified these species as endangered (very high risk of extinction in the wild) in It is suspected that there is a demise of at least the 50% of the Caretta caretta population during the last 10 years or three generations. Worldwide the international communities are concerned about the critical situation of the sea turtles, thus several international conventions have been created for their protection. For example, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) forbids trade of all marine turtle species. The Convention on the Conservation of Migratory Species of Wild Animals (CMS), known as Bonn Convention, contributes with valuable tools for the conservation and management of migratory animals. The Convention on the Conservation of European Wildlife and Natural Habitats, known as Bern Convention, recognizes the sea turtles as strictly protected, and the Convention on the Protection of the Mediterranean Sea against Pollution (Barcelona Convention) considers the marine turtle in the Endangered and Threatened List of species. The Sea Turtles have established one important population in the Mediterranean Sea, which breeding is achieved meanly in Greece, Turkey, Cyprus and Libya. The estimated number of mature females that nesting in the Mediterranean Coasts annually is from to for the loggerhead, and for the green turtle (Broderick et al., 2002). Actually only the loggerhead turtle is nesting in Greece. The number of nests found on the Greek coastline is around 2500 per year, where Laganas Bay (Zakynthos) is the more representative follows by Kyparissia Bay, Rethymno, Chania and Bay of Messara in Crete (Margaritoulis and Rees, 2003) Impact of the tourism development The Mediterranean beaches are now the most important tourism target in Europe, and represent around the 30% of the international tourism destinations. In the Mediterranean Coast the tourism industry is also the first economic income (Demetropoulos, 2000). It helps to generate employments and development of the urban areas. As early as 1970, over 58 millions international tourists visited the Mediterranean countries, in 1990 their number increased to 153 millions and in 2002 to 228 millions. According to the predictions of WTO (World Tourism Organization) and Plan Bleu the numbers could reach 396 millions by

16 TOURISM IMPACT ON THE SEA TURTLE Tourism industry has positive and negative consequences for the economy, environment and society. On the positive side, tourism represents an important economic income. For example, in Greece tourism contributes with the 7% to the country s GDP (Gross domestic product), and it affects directly to the percentage of employment (GNTO, 2000). In addition, it helps with the increasing of tourism infrastructure, cultural communication, and it facilitates the preservation of historical and environmental resources. On the other hand, tourism causes a lot of negative impacts on the environment and society. For example, alteration of the natural resources, cultural pollution and commercialization of human relations (Andriotis, 2001). Tourism industry on Crete, the biggest island of Greece, represents a threat to breeding and to the survival of the loggerhead turtle. Some human activities such as artificial lights, noise from the taverns and discotheques, human presence on the beach at night, and the increasing number of umbrellas and sun beds on Mediterranean Sea shores cause a negative impact on the nesting and hatching processes. The breeding period coincides with the massive influx of visitors because the tourism in Crete is mainly coastal tourism and as consequence strongly seasonal. As a consequence nesting beaches have been became tourist beaches. Additionally, the uncontrolled and unplanned development tourism in Greece contributes to the degradation of the coastal ecosystem. Leisure installations such as hotels, restaurants, bars, and the removal of the surrounding vegetation cause considerable erosion, which degrades the sand quality of the coast (Katselidis and Dimopoulos, 1998). The concentration of tourism, the lack of a land use planning and waste management, and the uncontrolled building construction cause serious environmental pollution in the island (Andriotis, 2001). In that way the weak management and the little support of the Greek government are also one of the causes for the threat of the marine turtle Suitable nesting beaches threatened by tourism development The base of turtle conservation is the protection and management of nesting beaches. Mature female turtles cannot reproduce without nesting beaches (Demetropoulos, 2000). Although this fact is obvious, it involves a lot of importance within the sea turtle protection. In particular the female turtles don t breed on any beach. When they are mature they return faithfully to their natal beaches in order to lay the eggs. If they cannot find suitability on these beaches, they leave the eggs in the sea, causing the decreasing of the Caretta caretta population in the Mediterranean Sea. According to Arianoutsou (1998) the main reason that makes beaches unsuitable for breeding is the tourism development. Consequently, the identification of suitable areas for Loggerhead nesting taking into consideration the tourism impact could be an effective management strategy for the protection and conservation of this specie (Panagopoulou and Dimopoulos, 2003) because in that way the government and NGOs could concentrate their efforts on specific areas within the tourism beaches. 2

17 TOURISM IMPACT ON THE SEA TURTLE 1.2 Research problem The nesting beaches of the endangered loggerhead turtle are affected by tourism development in Crete. Due to the intensive tourism activities on the Cretan coast all the breeding phases such as emergences, nesting, incubation of the eggs, and descent of hatchlings towards the sea are in danger. First, the artificial lights and noise disturbances caused by taverns, hotels and restaurants prevent female turtle from nesting on the coast. Therefore, they cannot reach the sand with the purpose of laying the eggs. In addition, several sun beds stand on the way of the female turtle working as barriers. Specially the umbrellas can cause damages to the eggs and alter the incubation temperature, influencing to the hatchling sex. When the hatchlings emergence from the chamber the lights of roads and restaurants disorientate them away from the sea. This occurs because they orientate towards the sea by its brightness, but they get confuse with the artificial lights and go in the wrong direction. If the baby turtles stay on the beach for extended periods of time, they are more vulnerable for the predators or they can die for desiccation or overheating. Besides, a large number of tourists disturb nests. Some activities such as driving of vehicles or trampling on the sand cause collapses of the nests or compaction of the sand. It makes the emergence of the hatchlings more difficult. Consequently the sea turtle nesting habitat are less suitable for reproduction causing a dramatic decline of the Caretta caretta population. Crete Island is the most dynamic tourist place in Greece but with some management problems with the environment. Its beaches, architecture, and natural resources make Crete in an important tourism destination with a great potential for further developments. Although the government had developed some plans, laws and policies to control the tourism industry, Crete has several difficulties with the management of these activities. For that reason, it is very important to concentrate the new studies in understanding tourism impacts and the relationship with the nature. Hence, this knowledge will help to the decision makers to develop some new strategies and policies according to the real needs in a sustainable way. 1.3 Research objective General objective To analyze the potential impact of the tourism development on Loggerhead Sea Turtle nesting in Rethymno, Crete Specific objectives To analyze the relationship between sea turtle nesting density and tourism development. To predict the tourism development and the impact on the nesting population for the next years. To determine the habitat suitability for Loggerhead Turtle breeding taking into consideration the tourism development on the years 1945, 1997, 2004 and

18 TOURISM IMPACT ON THE SEA TURTLE 1.4 Research questions 1a) What is the temporal relationship between tourist development and nesting density? 1b) What are the predictions for nesting density and tourism development in Rethymno taking into consideration the temporal aspect? 2) What is the relationship between nesting density and tourism infrastructure at beach scale? 3a) Where are the suitable areas for sea turtle nesting taking into consideration the tourism and environmental variables? 3b) How much has the suitable areas decreased in the last years? 1.5 Hypotheses H1 0 : There is not a significant temporal relationship between tourism development and nesting density of C. caretta on Crete. H1 1 : There is a significant temporal relationship between tourism development and nesting density of C. caretta on Crete. H2 0 : The tourism infrastructure does not have a significant relationship with nest density at beach scale. H2 1 : The tourism infrastructure does have a significant relationship with nest density at beach scale. H3 0 : The nesting habitat suitability does not have a significant relationship with nest density for C. caretta. H3 1 : The nesting habitat suitability does have a significant relationship with nest density for C. caretta. 1.6 Research background About loggerhead sea turtle (Caretta caretta) Although it is not the aim of this study to make a summary of sea turtles biology, it is important to understand some relevant aspects of their behavior and lifestyle. This knowledge will help for an appropriate protection of this marine specie taking into account their needs and repercussions on turtles breeding. The sea turtle is a reptile that exists since the time of the dinosaurs 90 millions ago. As many marine animals like dolphins, seals and whales they have reversed their evolution, returning to the sea. But in the case of sea turtles this reverse process was not complete. Although they can swim very well and stay under the water for long periods of time, they still need to breathe air and emerge to ashore to deposit 4

19 TOURISM IMPACT ON THE SEA TURTLE their eggs. This last fact causes the downfall of the sea turtles and at the same time help for the application of some conservation strategies, not often possible in other marine animals. As a briefly description, sea turtles are vertebrates found all over the world in tropical and sub-tropical oceans. Their dominated habitats are the littoral environments having an important role in the balance of food and energy cycle in marine and coastal ecosystems. They do not need to drink fresh water. The salt excess can expel through special glands in the eyes. Their eyes are adjusted for the life in the sea, for that reason sea turtles don t have a good vision on land. In addition, like other reptiles they are ectotherm, which means that the temperature of the body depends on the temperature of the environment. Loggerhead Turtles is divided in five populations: the Atlantic Ocean, Pacific Ocean, Indian Ocean, Caribbean and Mediterranean Sea. Then these populations are further divided into nesting rookeries. The majority of the nesting areas are located in temperate and subtropical regions. In the Mediterranean Sea there are encountered basically three species of sea turtles, Loggerhead Caretta caretta, the Green Turtle Chelonia mydas and the Letherback Dermochelys coriacea. This research is concentrated only on the first one, which according to some genetic studies their origins comes from the western Atlantic at the end of the last glacial period years ago (Bowen et al., 1993) Loggerheads are one of the largest sea turtles, reaching an average length of 95 cm and a weight of 120 kg. They are characterized by their very large head and by a reddish brown bony shell. They are mainly carnivore, and their diet is basically crabs and other crustaceans, shellfish, sponges, sea jelly and fish Nesting behavior The Loggerhead nesting season occurs since the middle of May until the middle of September. It mainly happens at night, usually after 22:00, or in the late afternoon, and it is rare the nesting after 3:00 am. The females dig a hole, usually 10 to 15 m from the sea (Arianoutsou, 1998), with their flippers until they can no longer touch any sand. The nests have a depth of cm (Arianoutsou, 1998) and a diameter of 25 cm. According to Margaritoulis (1988) the number of eggs per clutch in Greece ranges from During the laying the female is in a trance like state. It seems that she doesn t realize of the onlookers. Finalizing this stage, the turtle cover the nest with sand trying to hide it. All this process takes more or less one hour, but it also depends of the characteristics of the sand and the attempts until she finds the right spot. Sea turtles nest three or four times per season, and lay eggs in two years cycle (Broderick et al., 2002). A detailed description of the Nesting Process can be found in the Biological Report written by Dodd (1988). The nest site selection is a key component of hatchlings survival. Nests that are located close to the sea are more vulnerable to erosions and inundations caused by high sea, whereas nests located far away from the sea have bigger probability of predation or desiccation (Oz et al., 2004). In addition, according to a study made by Oz et al., (2004) the nests place within 20 m from the sea have 0% of success. 5

20 TOURISM IMPACT ON THE SEA TURTLE The sea turtles return to their natal beaches, where they incubated and hatched to lay the eggs. This behavior has a biological importance since that is the result of a natural selection made by their parents, who selected the most appropriate beach (Demetropoulos, 2000). The scientific explanation for this fact is still topic of discussion, but this imprinting could be clarified by some factors such as the magnetic field, wave direction and the chemistry of the sand. The fidelity of the sea turtles to return to their natal beaches has a significant conservation repercussion, because it makes distinctions in the populations (Bowen et al., 1992). This fact involves that each rookery should be protected independently, and the conservation activities won t help other rookeries Egg development Caretta caretta is Temperature-Dependent Sex Determined (TSD) animal, which means that the nest temperature influences in the determination of the hatchlings sex ratio. According to different studies the pivotal temperature is 29 C (Kaska et al., 1998). Nests with temperatures below this value are more likely to produce males and nests with temperatures above the pivotal temperature are more likely to produce females. In Greece the incubation of the eggs takes a period of 50 to 70 days. This period depends basically on the temperature, and other environmental factors. The baby sea turtle spends more than 2 days in the nest before to move upward the beach surface. The difficulty and the duration of the emergence depend on the nest depth and the sand compaction (Miller et al., 2003) Hatching and behavior of baby sea turtles Hatchings emerge from the nest since the middle of July until October (Margaritoulis, 2005) mainly during the night between 9:00 pm and 02:00 am. Once they are on the beach surface they walk towards the sea guided by its brightness, which is identified primarily by vision. It seems that hatchlings are more sensitive to cool lights (blue) and less sensitive to red lights. In the case of the adults they are more sensitive than the babies and both are insensitive to yellow lights (Demetropoulos, 2000). If the hatchlings don t get disorientated with the lights they reach the sea and immediately they start swimming taking advantage of the retreating tide. After this it is uncertain what happen with the baby sea turtles. Some scientists called this period as the Lost Years Maturity The age of sexual maturity is uncertain. According different studies it has been estimated between 10 and 30 years (IUCN), but Encalada (1998) suggests that C. caretta reaches the sexual maturity at 20 and 30 years old (Encalada et al., 1998). The sexual maturity age varies between populations. Dodd (1998) proposed that the sea turtles in Greece are the population with the smallest nesting females. Their sizes fluctuate between 70 and 95 cm (Dodd, 1988). It is important to consider that this is not a reference for the age. Also the period of life of sea turtles without any interference can be 60 years and they can be fertile for at least 3 decades. 6

21 TOURISM IMPACT ON THE SEA TURTLE Navigation and migration Loggerhead sea turtle is a specie that travels long distances. In average the speed of traveling is 1.2 km h -1 (Bentivegna, 2202). The modality of travel is according the life cycle period. For example, hatchlings float passively in sea current system, juveniles and subadults usually feed near the coast (Bowen et al., 1993). Adult females travel long distances between feeding and breeding areas. Although the information about the migratory habits of males is not clear, it was proposed the female turtles migrate long distances while adult males stay near the nesting beaches (Henwood, 1987). Moreover sea turtles migrate between western and eastern Mediterranean following a seasonal pattern influenced by the temperature and food availability (Bentivegna, 2202) Facing the hazards of humankind The demising number of sea turtles worldwide is caused directly by human actions. In 2005 the Burning Issues Assessment, elaborated by the marine turtle specialists of the IUCN, identified five main hazards to the sea turtle preservation. These threats were selected according the degree of impact on the decreasing of sea turtles, in their extinction, or in the recovery of the population (SWOT, 2006). A summary of the five hazards is shown in the table 1.1: HAZARDS DESCRIPTION IMPACT AFFECTED STAGE Longlines By catch mortality, habitat Juveniles and adults Fisheries impact Gill nets degradation, changes in the Trawls food web Hooks Constructions Increase population/ tourists Alteration of Vegetation Degradation of nesting beaches Nesting, eggs, and hatchlings Coastal Development Direct Take Pollution and Pathogens Global Warming Noise Disturbance Scare away females turtles Nesting from the nesting beaches Seafloor dredging Alteration of coastal ecosystem Hatchlings, juveniles and adults Vessel Traffic and speedboats Scare females away from the beach, collisions cause injures or death Hatchlings, juveniles and adults Predators (dogs) * Sea turtles are preyed on by Eggs and hatchlings domestic dogs Direct fishing Exploitation based on Eggs, juveniles and adults commercial and cultural practices (eggs, oil, leather, shell) Marine debris (Plastic bags and discarded fishing gear) Oil contamination Chemical pollutants Light Pollution Temperature increase Frequency of extreme weather events Ingestion, entanglement cause turtle mortality Intoxication caused immobilization exhaustion Sea turtle s immune system becomes weaker Disrupts nesting behavior, and cause hatchling disorientation Impact the sex ratio of hatchlings Degradation of nesting beaches, increase the likelihood of diseases Alterations of sea turtle habitats and oceanographic processes Destruction of coral reefs Table 1.1 Human impacts on the sea turtle population * When the predators are wild animals like foxes or ghost crabs, it is consider as a natural cause. Juveniles and adults Juveniles and adults Juveniles and adults Female adults and hatchlings Hatchlings Eggs, hatchlings, adults Juveniles and adults 7

22 TOURISM IMPACT ON THE SEA TURTLE Limitations of the tourism impact analysis on sea turtle breeding As it was not possible to get historical data about the nesting locations, number of eggs, number of emergences and hatchings success in Rethymno, the analysis of the tourism impact on the nesting sites in previous years were limited. In addition, the short time for the fieldwork and also its period (September October) didn t allow analyzing all the breeding process. During the data collection it was possible only to locate the nesting success. In this study nesting success were understood as the fact that female sea turtles arrive to the beach and lay their eggs without any interruption. The proof of the achievement of this stage is the presence of the nests along the beach. The analysis of the tourism impact on the hatching success could not be done because of the scarcity of the data. Consequently the study of the tourism impact on the sea turtles was based just on the nesting process (see Figure 1.1) and not on the whole breeding process. MAY OCTOBER Artificial Lights Noise Human presence Predators Egg Collection Sand Compaction Digging up Erosion Inundation Climate Change Artificial Lights Human Catching Moon Light Predators DISORIENTATED HATCHLING FEMALE TURTLE LAYING EGGS EGGS DEVELOPMENT HATCHLING EMERGENCE Artificial Lights Human Presence Artificial barriers Noise Natural Barriers FEMALE TURTLE ARRIVING FEMALE TURTLE LEAVING NATAL BEACH HATCHLINGS REACHING THE SEA Vehicles Artificial Barrier Human Catching Predators MATING Boat Collision Direct take Oil/Chemical Pollution Marine Debris Bycatch V Predators JUVENILE STAGE ADULT STAGE SEA SUBADULT STAGE Human Impact Non Human Impact Nesting process YEARS Figure 1.1 Human and non human impacts on sea turtle cycle life Environmental requirements vs. human disturbances along nesting beaches The basis of this study was to analyze deeply the impact of the tourism development on the nesting stage of the C. caretta. One of the main elements considered on this process is the beach selection done by the female turtles. The identification of the ideal environmental characteristics associated with nesting success gives several guides of the habitat requirements for these animals. Once knowing the needs of loggerhead it was easier to recognize the consequences of human disturbances on the sea turtle habitat. For that reason, a short explanation about the biophysical factors was considered necessary. 8

23 TOURISM IMPACT ON THE SEA TURTLE It is important to take into account that nest-site selection is a maternal effect that determines the offspring survival and changes in its phenotypes. Kolben and Janzen (2002) suggested that sea turtles prefer to nest in sandy than grassy patches, and also in the areas with shorter vegetation because the overstory can affect the sex ratio of the population (Kolbe and Janzen, 2002). Moreover the female avoid the presence of predators on the beach. According to various sea turtle scientists, the dimension of the beach, geomorphology, and sand texture are also important factors that take part on the beach selection. Kikukawa (1999) analysed all these parameters and concluded that sand softness, high beaches and distance from the nearest human settlement have a positive impact on beach selection, while the length of the beach has a negative relationship (Kikukawa et al., 1999). The sand softness indicates that sea turtles prefer beaches where the digging of the nests is easier. The positive relation with high beaches is understandable taking into account that loggerhead turtles lay their eggs above the sea level to avoid inundation of the nests. The last positive observation confirms that sea turtles choose beaches far away from the human activities. And finally the negative relationship with the length of the beach could be explained with the fact that long beaches tend to develop more urban infrastructures. In accordance with this list of habitat requirements the last two factors have a direct relationship with human activities. In the following paragraph a deep explanation will be done about these impacts. Different studies related with the human impacts on the sea turtles nesting indicate that loggerhead prefer dark beaches for their nests (Mann, 1978). For instance, the artificial lights dishearten Loggerhead to come ashore on the sandy beaches, and cause the lost of the eggs because after some attempts the female throw them on the sea. Also the light bright can scare the female turtle during the laying of the eggs, interrupting the nesting process (Arianoutsou, 1998). Consequently it is clear that artificial lights must be considered as a direct impact on the nesting process. But the lights are not the only factor that disturbs the required quite nesting beaches. The noise also scares away the sea turtle from the seaside or disturbs the laying eggs process. Moreover the ears of sea turtles have a low frequency reception, around 60 to 100 Hz (Ridgway et al., 1969), which makes them more sensitive to any far-away noise. In that case artificial lights and noise could be categorized as direct impacts on the nesting beach selection, and also represent the main human alterations that avoid the nesting success. In order to measure the anthropogenic factors artificial light and noise, it is appropriate to consider which elements are their sources. Along an urban and tourist beaches the artificial lights are originated by nearby hotels, bars, restaurants, shops, parking lots and houses, as well as the cars lights driving near the beach. Although it is complicated to be measured the noise level, it is known that bars, restaurants, and cars along the beaches generate noise. Taking into consideration all these explanations the criteria that allowed the analysis of the tourist impact on the nesting beaches and more specific on the nesting success were the location of tourism accommodations, bars, restaurants, shops, parking lots, houses, and roads along the seaside (see Figure 2.3). Another very important factor that affects nesting success is the presence of artificial barriers on the sand. At the moment that loggerhead turtles arrive to the beach at night they find sun-beds, sun-umbrellas, areas 9

24 TOURISM IMPACT ON THE SEA TURTLE for children entertainment, and also some kiosks that belong to the water-sport centres. They stop the female turtles finding a suitable beach for the eggs chambers and also they minimize the area for nesting. These factors are considered as direct impacts to the nesting process, but unlike the lights and the noise they can be quantify directly. In that way, more anthropogenic factors were established: density of sunbeds, and recreational areas. Usually Loggerheads spend the day time in the shallows near the nesting beaches, motivated by their warm water. It seems that the presence of people on the beach scare away this animal because it was proved that they prefer to swim in areas with few or no human presence. It is not confirmed yet that this statement could influence the nesting process at night. But the concentration of curious tourists during the night causes disturbances to the nesting process. For that reason the presence of people on the beach should be involved, but in this study it was not possible to obtain data about this statement. 10

25 TOURISM IMPACT ON THE SEA TURTLE 2 Materials and Methods 2.1 Study Area Crete is the largest island in Greek and the fifth in the Mediterranean Sea. It is divided in four prefectures Chania, Heraklion, Lassithi and Rethymno. According of the census in 2005 Crete has 623,666 inhabitants and a population density of 75/km 2. The prefectures of Heraklion and Rethymno contain the highest growth rates population, 40.36% and 34.12% respectively (Pamfilos, 2005). Crete has two climatic zones, the Mediterranean and the North African. In general the weather is temperate and the humidity depends on the proximity to the sea. During summer the temperature is around 20 to 30 C Tourism development in Crete Crete is one of the most known tourism destinations in Greece due to some important archeological places such as the Minoan sites of Knossos and Phaistaos, monasteries and also many other monuments. Furthermore the island is known for the richness of its culture, food and beauty of its landscapes, such as the hinterland and the beaches. Nowadays, Crete with 2.9 million visitors per year represents the third most important tourist destination in the Mediterranean. Tourism development in Crete had been followed a series of phases. According to the literature review it was divided basically in three periods 1) 60 s to middle of 70 s, 2) middles of 70 s to middles of 80 s, and 3) middle of 80 s up to the present. Before the introduction of the tourism activities in 1960, the economy of Crete was based on the agriculture and handicrafts manufacturing (Tsartas, 2003). During this period the distance from the Island to the continent, the low level of infrastructure, the bad communication and the continuous wars were the obstacles to develop the tourism. After 1960 Crete improved its basic infrastructure, and started to exploit its natural beauty, good weather, and cultural heritage as tourist attractions (Andriotis, 2003). Between 1968 and 1975 the construction of more hotels in Crete were done, and as a consequence during the period 1975 and 1978 the number of beds doubled (Technical Chamber of Greece Crete, 1981). After the middle of 70 s the tourism industry lived a period of accelerated growth. In 1981 Greece began to be part of the European Union, and as a consequence an important amount of funds started to improve the economy of this island. After that in 1986 the number of hotels increased to 736 and in 1990 to 1292 units. The spatial distribution of the tourism activities in Crete is unequal. It is considered that the 70% of the hotel establishment, as well as the local population are concentrated in the northern coast (Eurostat, 1994). In addition Crete had developed a fast growth in the tourism industry due to during the last decades the Greek government had considered Crete as a top priority in the tourism development (Tzouvelekas and Mattas, 1995). Additionally there were several incentives for the construction of hotels e.g. interest-free subsides, and non-taxable allowances (Andriotis, 2003). But since the end of the 1990 some negative effects could be identified due to a chaotic tourism development, and nowadays people are concerning about the evaluation of these repercussions. 11