The Impact of Built-Up Area Dispersion on the Cultural Heritage of the Region of the South Aegean, Greece

Abstract

Cultural heritage serves as a repository of a place’s history and identity, integral to its landscape and central to all three sustainability goals. However, managing and protecting cultural heritage through regulatory planning often proves inadequate. This particularly applies to islands where infrastructure development pressures and urban sprawl lead to significant changes. This study quantifies the impact of uncontrolled built-up area dispersion on islands’ cultural heritage, focusing on the Southern Aegean region. By identifying and delineating the boundaries of archaeological areas and historic sites, we assess pressures through the mapping and quantitative analysis of built-up areas derived from the Global Monitoring for Environment and Security (GMES) program. The results reveal spatial relations and potential conflicts, underscoring the insufficient protection of cultural heritage due to inadequate management and ineffective planning tools. Specifically, on islands like Mykonos and Naxos, over 80% of their archaeological areas are impacted by urban sprawl. Additionally, this study finds that six islands (Antiparos, Irakleia, Kea, Mykonos, Paros and Patmos) have over 60% of their built-up areas in exurban regions, exacerbating pressures on heritage sites. These findings highlight the need for an integrated spatial planning system that incorporates landscape and cultural heritage assets into strategic planning regulations, ensuring the preservation of these essential resources amidst ongoing development pressures.

1. Introduction

Islands, by their very nature, possess unique characteristics that set them apart from continental landmasses. They often feature distinct ecosystems, biodiversity and geological formations shaped by their isolation and specific climatic conditions [1,2]. Moreover, islands frequently exhibit a rich cultural diversity, influenced by centuries of maritime trade, colonization and indigenous traditions. The limited land area and restricted resources on islands have led to the development of resourceful and sustainable practices. These practices range from innovative agriculture and fishing techniques to efficient water management systems [3]. Additionally, island environments often foster tight-knit communities with strong social bonds and a deep connection to their surroundings [4]. As such, islands represent not only particular natural ecosystems but also significant cultural landscapes that need protection and management [5,6,7].

Islands possess a rich and unique cultural heritage, deeply rooted in their geography, history and interactions with neighboring cultures. The tangible dimension of this heritage endures and continues to emerge today, primarily expressed through archaeological sites and monuments. In addition to their historical significance, these sites also contribute to island development by attracting tourism and providing economic benefits [8,9,10].

Cultural heritage plays a pivotal role in shaping the spatial development patterns of built-up areas, influencing the distribution and expansion of urban landscapes. Communities, in their quest to preserve their cultural heritage, tend to focus development around historic sites, traditional settlements or areas of cultural significance. This phenomenon, known as cultural clustering, leads to the dispersion of built-up areas as development gravitates towards these culturally important locations [11,12]. The preservation of cultural heritage is becoming increasingly vital amidst the challenges posed by built-up area dispersion. Developmental pressures often threaten historic sites and traditional communities, placing invaluable cultural assets at risk of being lost [13,14,15].

In island territories, this issue becomes even more acute and complex due to escalating tourist development and the growing demand for second homes, which intensify residential pressures [16]. The location and expansion of built-up areas in the limited space of the islands are influenced by both natural and human-induced factors, such as topography, proximity to the sea, access to the road network and closeness to areas of cultural significance, such as traditional settlements and archaeological sites [17,18,19].

Hence, the situation on the Greek islands presents a complex interplay between urban sprawl and the management and preservation of cultural heritage [20,21,22,23]. The absence of a consistent and up-to-date spatial planning system has led to unregulated development, resulting in urban sprawl [24,25]. This unregulated development poses significant challenges to the preservation of the islands’ rich cultural heritage, as historic sites, traditional settlements and areas of cultural significance become increasingly threatened. The rapid construction of small, individual properties, often outside the framework of spatial planning, exacerbates the problem by driving further urban sprawl in exurban areas—defined here as development that occurs beyond the institutional limits of the settlements and is not subject to the regulatory processes governing urban areas [26,27,28,29,30].

The balance between tourism development and the preservation of the islands’ cultural heritage is delicate. On the one hand, cultural tourism is an important economic asset for the islands, also providing a strong incentive for the preservation of cultural heritage [31]. On the other hand, mass tourism creates intense pressures mainly through unregulated construction. An integrated spatial planning system is considered key for the proper protection and management of cultural heritage, combined with the promotion of sustainable tourism—tourism that supports economic growth while preserving cultural and natural resources for future generations [32,33,34,35].

In recent years, research on urban sprawl and cultural heritage preservation has largely focused on broader or more generalized case studies. This study, however, is the first to apply this specific methodology to the Southern Aegean archipelago. The region presents a unique combination of factors such as island size, population density and a high concentration of significant cultural monuments, making it an ideal subject for this analysis. The Cyclades and Dodecanese islands, in particular, feature complex patterns of urban expansion that directly intersect with areas of historical and archaeological importance. By examining built-up areas both within and outside official settlement boundaries, this study offers insights into the relation between urbanization and cultural heritage, filling a gap in the existing literature and providing a new perspective on the challenges of heritage preservation in these regions.

This paper aims to highlight this issue through the quantitative analysis of built-up areas located within cultural heritage sites on the islands of the South Aegean region. This phenomenon is driven by pressures to develop infrastructure for mass tourism and the inadequacies of spatial planning systems in preventing construction in these culturally sensitive areas. More specifically, the aim of this study is to examine the relation between deficiencies in spatial planning, urban sprawl and their effects on cultural heritage in island regions. The main hypothesis of this study is that the interplay of developmental pressures, leading to the dispersion of built-up areas, combined with shortcomings in spatial planning’s capacity to protect cultural heritage areas, has contributed to significant spatial alterations on islands that threaten the cultural landscape.

The objectives of this research are as follows:

• To quantify built-up area dispersion: this involves assessing the extent of built-up areas within and outside settlement delineations to understand spatial development patterns and their intersection with cultural heritage sites.
• To evaluate the impact on cultural heritage: this study seeks to analyze the direct and indirect impacts of built-up area dispersion and infrastructure development on archaeological sites, traditional settlements and other culturally significant landscapes.
• To propose integrated management approaches: this study aspires to contribute to the discourse on spatial planning and heritage preservation by advocating for an integrated planning system that balances development with sustainability and cultural integrity.

Focusing on the South Aegean region in Greece, which comprises the Cyclades and Dodecanese archipelagos encompassing 38 islands, this research addresses two key research questions: (a) to assess the extent of the built-up area within and outside settlement delineations and (b) to analyze the impact of built-up dispersion on cultural heritage areas. These research questions will be answered through the quantitative analysis and mapping of pertinent variables, utilizing geoinformatics tools. The interpretation of the findings will be based on “Spatial Planning Principles”.

The scientific significance of the South Aegean region lies in its rich cultural and historical identity, represented through its archaeological sites, traditional settlements and other culturally significant landscapes. As a region facing intense development pressures, it serves as an ideal case study for understanding how unregulated urban sprawl and deficiencies in spatial planning systems impact cultural heritage. The insights derived from this study are not only applicable to Greece but also offer valuable lessons for similar island territories globally, where the delicate balance between development and preservation is often at risk.

The structure of this paper is organized as follows: Section 2 explores spatial planning and cultural heritage protection, highlighting key policy considerations at various spatial levels. In Section 3, the data sources and methodology employed in this study are described, and the geographical context of the study region is also presented. Section 4 presents the empirical results, supported by tables and figures that clearly illustrate the findings. Finally, Section 5 provides a discussion of the results’ implications and offers concluding insights along with recommendations for future research and policy development.

2. Policy Considerations for Cultural Heritage Protection at Various Spatial Levels

At the international and European levels, the importance of cultural heritage has been recognized for nearly a century. The First International Congress of Architects in Athens in 1931 initiated this effort with the formulation of the “Athens Charter”, which highlighted the cultural elements of the broader urban environment as cultural assets [36,37]. In 1964, the adoption of the “Venice Charter” expanded the concept of a monument by recognizing that “The concept of a historic monument embraces not only the single architectural work but also the urban or rural setting in which the evidence of a particular civilization, a significant development or a historic event is identified.” [38].

A milestone for the protection and management of world cultural heritage was the adoption of the 1972 Convention Concerning the Protection of the World Cultural and Natural Heritage [38]. In 1985, the Granada Convention for the Protection of the Architectural Heritage of Europe established the principles of the European cooperation on and coordination of architectural conservation policies [39]. In 1992, the Valetta Convention on the Protection of the Archaeological Heritage was adopted with the aim of protecting archaeological heritage from illegal excavations and major construction projects [40]. In 2003, a convention adopted at the international level highlighted the intangible attributes of cultural heritage [41,42]. The Convention for Safeguarding the Intangible Cultural Heritage introduced a new dimension to cultural heritage by including human traditions and ways of living [43,44,45,46,47,48].

The aforementioned conventions have been ratified by the Greek legislative system, further enriching the legislative context at the national level [49]. In Greece, the protection of cultural heritage is regulated, established and protected by the National Constitution, specifically Article 24. Antiquities legislation was governed by Law 5351/1932 “Amendments and Additions to Law 5356/1912 ‘Concerning Antiquities’” [50] and later by Law 1469/1950 “Protection of Buildings and Works of Art Post-1830” [51], which address their protection before and after 1930, respectively. However, these laws do not provide a comprehensive management framework for cultural heritage sites and the landscape. Law 3028/2002 “On the Protection of Antiquities and Cultural Heritage in General” [52] plays a central role in the legislative context, establishing the framework for the protection of the Greek cultural heritage from ancient times to the present and emphasizing the preservation of historical memory for present and future generations. Article 3 of this law emphasizes the importance of integrating cultural heritage protection and management into all levels of spatial planning across the country. Additionally, Law 4858/2021, titled “Ratification of the Code of Legislation for the Protection of Antiquities and Cultural Heritage in General” [53], addresses the protection of antiquities and cultural heritage. It introduces more detailed provisions for the spatial regulations surrounding the protection of antiquities and cultural heritage, focusing on how spatial planning must consider cultural heritage preservation as part of urban and land-use strategies.

The need to protect and manage cultural heritage through spatial planning is evident from the above brief reference to the national legislation on cultural heritage. In spatial planning laws and their reforms, although both natural and cultural heritage are acknowledged as invaluable and therefore highly prioritized assets in terms of protection and management at the national, regional and local spatial planning level, the implementation of this direction in spatial frameworks and plans is insufficient and fragmentary. Protection has mainly been attempted through regulatory measures at the local spatial planning level by means of General Urban Plans (GUPs) and Open City Spatial and Housing Organization Plans (OCSHOPs) [54,55]. However, these plans have so far been institutionalized for a very small percentage of the territory. The regulatory zones that have been used in Greece to address issues arising from the insufficient spatial planning context are the Urban Development Control Zones (UDCZs) [56]. These are typically exurban areas with strict terms and building conditions to prevent development outside the official settlement delineations. Although UDCZs were not designed to prioritize cultural heritage protection, they could have an indirect effect through the prevention of exurban built-up area expansion. However, this was not implemented, on the one hand, due to the small percentage of land of area they occupy and, on the other hand, due to the delay in their institutionalization.

Our study area is limited to only a few islands, including Syros, Mykonos, Paros, Naxos, Patmos, Andros, Santorini and parts of Kos and Rhodes. Despite their presence, the percentages of built-up areas outside settlement boundaries remain high. For example, the percentages of built-up areas outside settlements are 40% for Syros, 89% for Mykonos, 60% for Paros, 48% for Naxos, 86% for Patmos, 53% for Andros, 20% for Santorini, 52% for Kos and 46% for Rhodes. Of these, significant portions directly impact cultural heritage, with nearly 100% in Mykonos, 86% in Naxos, 80% in Santorini, 53% in Rhodes and lower percentages in Patmos, 2%, and Andros, 7%.

Cultural heritage is a spatial component that requires a cohesive and consistent approach to spatial planning for its preservation and management. UNESCO’s concept of cultural landscapes emphasizes the connection between human activity and the natural environment, offering a key perspective for integrating both tangible and intangible heritage. This integration was introduced in spatial planning through the 2012 revision of the Regional Frameworks on Spatial Planning and Sustainable Development [53,57]. These landscapes represent the interaction between natural and cultural elements, highlighting the need to protect them from urbanization and infrastructure expansion.

Urban sprawl theories explain how built-up areas can spread unregulated beyond designated boundaries, posing risks to cultural heritage preservation [58,59]. Spatial planning theory stresses the importance of integrated frameworks to balance competing land uses and protect cultural heritage while attempting to address development pressures [28,60,61].

Though the 2012 revision of the regional frameworks is a positive step, more needs to be done. The landscape should be further incorporated into special spatial frameworks that focus on activities with a high spatial impact, along with more specific regulatory measures at the local planning level [62].

3. Materials and Methods

3.1. Data and Methodology

In this section, an overview of the spatial data and methodologies employed in this research is presented, with a focus on evaluating the impact of built-up areas on monuments and cultural heritage sites in the South Aegean region of Greece. This analysis follows the steps shown in Figure 1.

The research began by inventorying and mapping cultural assets across the study area, using Geographic Information Systems (GISs). Monument locations, sizes and settlement boundaries were systematically collected from various archival sources, including historical records, Official Government Gazette Sheets and existing geospatial datasets available in open databases.

Data on cultural heritage sites were primarily obtained from the Archaeological Cadaster managed by the Ministry of Culture and Sports [63,64], as well as the Thal-Chor Project [32,65]. This cross-border initiative aligned with Directive 2014/89/EU on Maritime Spatial Planning, providing valuable insights into both terrestrial and marine archaeological boundaries, particularly on islands where cultural assets extend into the sea.

The Official Government Gazette (OGG) [66] provided essential data for traditional settlement boundaries, downloaded from the government webpage as topographic charts and orthophoto maps. These were georeferenced using the Greek Geodetic Reference System 1987 (GGRS87) for spatial compatibility. Settlement boundaries for official settlements were sourced from open platforms such as e-poleodomia [67]. For traditional settlements without corresponding OGG records, their boundaries were digitized using information from OpenStreetMap. These steps ensured comprehensive mapping and analysis of settlement boundaries across the region.

Subsequently, the settlement boundaries were digitized with GIS software (QGIS 3.34), ensuring high spatial precision at a scale of 1:5000. To validate the georeferencing and digitization process, the boundaries were cross-referenced with cadastral maps provided by the National Cadaster and Mapping Agency, ensuring consistency and accuracy.

Geospatial datasets were central to analyzing the relation between built-up areas and cultural heritage sites. The Impervious Built-Up (IBU) layer for 2018, derived from the Global Monitoring for Environment and Security (GMES) program, provided binary classifications of built and unbuilt areas with a spatial resolution of 10 m [68]. This dataset offered detailed insights into the extent of urban development across the study area. Additional datasets, including soil-sealing data, allowed for the further analysis of built-up areas both inside and outside settlement boundaries.

For this research, we used open geospatial data from official sources such as GMES, the Archaeological Cadaster, e-poleodomia and OGG to ensure consistency, transparency and accessibility in addressing the research questions. This study focuses on the spatial analysis of built-up area dispersion and its impact on cultural heritage sites, relying exclusively on spatial data and official records, particularly the designated cultural heritage sites defined by the Archaeological Cadaster. As a result, the socioeconomic and cultural factors influencing urban expansion were not explicitly included in the analysis.

However, the poor quality of some OGG topographical charts and maps made certain boundary sections unclear. To resolve this, supplementary data from OpenStreetMap and orthophotos were used to clarify boundaries, with metadata verification ensuring all datasets complied with standardized formats and spatial reference systems.

The geospatial datasets were employed to measure and map built-up areas, distinguishing between those located inside and outside official settlement boundaries. This approach enabled the extraction of quantitative data essential for evaluating the extent of urban sprawl across each island in the South Aegean region. Mapping and visualization played a crucial role in the analysis, with thematic maps generated to illustrate the spatial relations between built-up areas and cultural heritage monuments. These maps, developed at a standardized working scale of 1:10,000, aligned with spatial planning requirements and maintained compatibility with the Impervious Built-Up (IBU) layer [69,70].

Raster analysis was used to examine how heritage sites spatially relate to built-up areas outside settlement boundaries. Officially delineated cultural assets were converted into raster format and overlaid onto built-up area datasets to identify intersections. This process allowed for both quantitative and cartographic assessment of the impact of built-up areas on cultural heritage, while traditional settlements were excluded from this specific analysis.

Additionally, statistical methods were employed to further explore the relation between island size, built-up area and its effects on cultural heritage sites. Using the Pearson correlation coefficient, this study analyzed the strength and direction of relations between variables.

Finally, the methodological approach of this research is based on the theoretical framework in Section 2, which focuses on integrating cultural heritage preservation into spatial planning. Using GIS tools and quantitative analysis, this study applies key concepts from urban sprawl and cultural landscape theories to assess how the built-up area dispersion impacts cultural heritage sites in the South Aegean region.

3.2. The Study Region

The islands of the Southern Aegean region of Greece (Figure 2) were selected as the focal point of this study due to their rich cultural heritage, numerous historical monuments and the urgent need to protect these assets from the pressures of built-up area expansion. This region is particularly significant because of its historical and cultural richness, combined with its unique geographical and socioeconomic characteristics. The islands face considerable urban sprawl and development pressures, especially along their coastal areas, driven by rapid population growth, expanding tourism and infrastructure deployment [71]. These factors pose significant threats to the integrity of the region’s archaeological sites and monuments.

Encompassing the Cyclades and Dodecanese archipelagos, the Southern Aegean region has long served as a vital crossroads in history, witnessing the evolution of various ancient civilizations, from the Minoans and Mycenaeans to the Romans, Venetians, Byzantines and Ottomans. Each civilization has left its architectural and cultural mark on these islands, contributing to a diverse and irreplaceable cultural heritage [71]. Monuments, churches, aqueducts and other structures attest to the enduring legacy of these civilizations, enriching the historical landscape of the region [72,73].

The Southern Aegean region covers approximately 5286 square kilometers (2041 square miles), with an estimated population of around 400,000 people [74]. The region consists of 48 islands in total, with 15 located in the Dodecanese and 33 in the Cyclades. Some of these islands are small and uninhabited, with no permanent population. For this study, we collected data and examined only 37 of these islands, specifically those with built-up areas and cultural heritage sites. Recognized for its extensive cultural heritage, the region contains 40 officially identified historical areas, 293 designated archaeological zones and 1573 monuments. These data were sourced from the Greek Archaeological Cadaster [64]. Additionally, there are 398 institutionalized settlements, including 159 traditional settlements with delineated boundaries (Figure 2).

According to the Archaeological Cadaster, archaeological areas encompass ancient monuments in terrestrial or marine sites that date from the earliest times up to 1830 and include monumental, residential or burial complexes. These sites are designated as “archaeological sites”, following a proclamation issued by the Ministry of Culture and Sports. Historical areas, on the other hand, refer to geographic ensembles, associated with significant historical or mythical events, featuring monuments and structures dating to before 1830. Monuments are classified based on their historical periods, ranging from prehistoric times to the post-Byzantine era, with newer monuments marked by their historical, artistic or scientific importance.

The Southern Aegean region faces rapid and unregulated built-up area dispersion, which significantly threatens its cultural heritage [17]. Urban development, driven by tourism, population growth and infrastructure projects, often encroaches on archaeological sites and historic landmarks. This challenge is compounded by inadequate enforcement mechanisms and a lack of comprehensive spatial planning, leaving the region’s heritage vulnerable to degradation.

The region was chosen for this study not only due to its rich cultural heritage but also because of the critical pressures it faces from urbanization and tourism. Heavy tourism inflows throughout much of the year drive the development of infrastructure, housing and commercial areas, further endangering its historical assets. Despite repeated legislative efforts, spatial planning has struggled for decades to balance growth with preservation [6].

The Southern Aegean’s challenges make it representative of broader issues faced by insular and coastal regions with high cultural and historical significance [10]. This region encapsulates the global struggle to reconcile heritage preservation with economic development, highlighting the urgent need for integrated spatial planning strategies to protect its unique cultural legacy while addressing socioeconomic demands [16,18].

4. Results

In this part, empirical results are presented and discussed, based on the data and methodology outlined in the previous sections. This analysis provides a detailed exploration of settlement patterns, built-up area dynamics and their relations with cultural heritage across the Southern Aegean islands. While the tension between development and heritage preservation is well documented, this study contributes novel, quantitative insights into the spatial dynamics and their specific impacts on cultural heritage in this region.

More specifically, in

Table 1. Comparison of traditional and non-traditional settlements on Cyclades and Dodecanese islands, Southern Aegean region, Greece. Source: own elaboration.

Islands of Southern Aegean
Cyclades Settlements—Traditional Settlements
Islands	Traditional	Surface Area km2/Total Island Area km2	Non-Traditional	Surface Area km2/Total Island Area km2
Amorgos	8	4.96	1	0.18
Anafi	-		1	3.97
Andros	7	4.02	34	15.61
Antiparos	-		1	1.037
Donousa	2	0.928	-
Folegandros	2	1.131	3	2.666
Ios	3	7.58	-
Irakleia	1	0.872	-
Kea	5	3.22	-
Kimolos	1	1.46	3	0.935
Kythnos	3	6.6	3	1.85
Koufonisi	-		1	5.201
Mykonos	2	12.33	5	7.22
Milos	5	3.69	5	6.35
Naxos	22	5.43	17	7.92
Paros	10	27.67	16	25.58
Schoinousa	-		1	1.926
Serifos	4	4.08	4	9.27
Sifnos	4	5.73	5	3.07
Sikinos	1	2.58	1	1.92
Syros	5	4.51	24	5.41
Santorini	7	2.598	14	8.285
Tinos	37	16.95	12	6.87
Dodecanese Settlements—Traditional Settlements
Arkoi	-	-	1	1.662
Astipalaia	5	3.127	-
Chalki	3	0.8572	-
Kalimnos	4	1.066	8	8.16
Karpathos	3	0.65	13	18.71
Kasos	-		4	3.736
Kos	-		4	2.805
Leipsoi	-		1	0.9044
Leros	-		9	8.99
Nisyros	3	0.53	1	0.382
Patmos	1	2.42	-
Rhodes	4	1.76	46	21.3
Simi	3	0.506	1	1.366
Tilos	3	1.334	-	-

, a comprehensive analysis of traditional and non-traditional settlements across the Cyclades and Dodecanese regions is provided, along with the ratios of the settlement surface area to the total island area. Such information highlights the distribution of settlements, with some areas having a high concentration, while others have few or none. For instance, islands like Paros, Naxos and Tinos in the Cyclades island complex have a notable concentration of traditional settlements, while others like Irakleia and Koufonisi have fewer or none. These findings highlight the uneven distribution of traditional settlements and their vulnerability to development pressures, underscoring the need for tailored conservation strategies that account for local contexts. Similarly, the prevalence of non-traditional settlements varies, with Santorini, Syros and Karpathos displaying higher shares of non-traditional settlements, compared to islands like Naxos and Rhodes. Noteworthy outliers include Leros and Leipsoi in the Dodecanese, which have significantly higher ratios of non-traditional settlements, covering 89.95% and 90.44% of their respective total island areas. Additionally, Kalymnos stands out with 81.6% of its area covered by non-traditional settlements. In the Cyclades island complex, Santorini has an unusually high percentage of non-traditional settlements (82.85%), while Tinos stands out for its large number of traditional settlements, covering 16.95% of the island’s area.

For example, on the island of Naxos, there are twenty two traditional settlements covering about 5.43% of the total island area. In contrast, there are seventeen non-traditional settlements, covering approximately 7.92% of the island’s total area, while on the island of Rhodes, there are four traditional settlements covering approximately 1.76% of the island’s total area and forty-six non-traditional settlements, covering approximately 21.3% of the island’s total area.

When comparing the total numbers, the Cyclades island complex displays 129 traditional settlements, covering 2.20% of the total island area, which is higher than that of the Dodecanese island complex, which has 29 traditional settlements that cover only 1.01% of the total area. This indicates a greater coverage of traditional settlements in the Cyclades complex. Conversely, for non-traditional settlements, the Cyclades display 151 settlements, covering 3.44% of the total area, slightly exceeding the Dodecanese’s 88 non-traditional settlements, which cover 3.12% of the area. This suggests a higher prevalence of non-traditional settlements in the Cyclades complex as well. Figure 3 and Table 1 detail the proportions of traditional and non-traditional settlements across the two island complexes of the Southern Aegean region, highlighting significant variations and the need for tailored conservation strategies.

The Cyclades and the Dodecanese are treated as distinct geographical units, reflecting differences in administrative geography, historically defined at the prefecture level (NUTS 3 [75]). Furthermore, phenomena such as tourism development display unique dynamics and characteristics in each region, justifying the separation of the two areas for this analysis.

The extensive network of traditional settlements in the Southern Aegean region reveals the architectural value of these settlements and highlights the role of urban planning in preserving and sustainably managing this value. Within the boundaries of traditional settlements, the legislation sets strict restrictions, as already described. However, integrated protection and management of the place that also takes into consideration the wider landscape of traditional settlements is significant and indispensable. One main cause of change in the islands’ landscape is the continuous construction activity in exurban areas. In

Table 2. Built-up areas (%) inside and outside settlement boundaries and their relation to total island area and population information: Cyclades vs. Dodecanese. Source: own elaboration.

Islands	Population (Census 2021)	Built-Up Areas (%) Inside the Settlement Boundaries	Built-Up Areas (%) Inside the Settlement Boundaries/Total Area	Built-Up Areas (%) Outside the Settlement Boundaries	Built-Up Areas (%) Outside the Settlement Boundaries/Total Area
Cyclades
Amorgos	1961	53.63%	0.26%	46.37%	0.23%
Anafi	293	67.61%	0.18%	32.39%	0.09%
Andros	8826	46.47%	0.14%	53.53%	0.17%
Antiparos	1265	29.39%	0.6%	70.61%	1.44%
Donousa	213	54.45%	0.27%	45.55%	0.23%
Folegandros	719	75.68%	0.62%	24.32%	0.2%
Ios	2299	48.75%	0.26%	51.25%	0.28%
Iraklia	148	31.89%	0.09%	68.11%	0.18%
Kea	2335	20.03%	0.13%	79.97%	0.51%
Kimolos	810	86.81%	0.4%	13.19%	0.06%
Kythnos	1568	43.55%	0.3%	56.45%	0.39%
Koufonisi	391	56.57%	2.01%	43.43%	1.54%
Mykonos	10,704	10.88%	1.43%	89.12%	11.71%
Milos	5302	67.01%	0.55%	32.99%	0.27%
Naxos	14,708	51.71%	0.44%	48.29%	0.41%
Paros	14,520	39.6%	1.46%	60.4%	2.23%
Santorini	15,231	79.41%	4.94%	20.59%	3.71%
Schoinousa	229	58.43%	0.46%	41.57%	0.32%
Serifos	1241	64.01%	0.32%	35.99%	0.18%
Sifnos	2777	53.79%	0.71%	46.21%	0.61%
Sikinos	253	75.64%	0.25%	24.36%	0.08%
Syros	21,124	59.91%	5.35%	40.09%	3.58%
Thirasia	249	57.12%	0.7%	42.88%	0.17%
Tinos	8934	57.53%	1.12%	42.47%	0.83%
Dodecanese
Arkoi	44	78.79%	0.04%	21.21%	0.01%
Astipalaia	1376	73.59%	0.29%	26.41%	0.1%
Chalki	475	98.26%	0.33%	1.74%	0.01%
Kalimnos	17,752	93.17%	2.09%	6.83%	0.15%
Karpathos	6567	46.79%	0.25%	53.21%	0.28%
Kasos	1223	89.98%	0.36%	10.02%	0.04%
Kos	37,089	47.87%	0.77%	52.13%	0.84%
Leipsoi	778	74.27%	0.43%	25.73%	0.15%
Leros	7992	66.79%	1.88%	33.21%	0.94%
Nisyros	1048	78.31%	0.08%	21.69%	0.02%
Patmos	3283	13.42%	0.36%	86.58%	2.3%
Rhodes	125,113	53.33%	0.77%	46.67%	0.67%
Simi	2603	96.68%	0.79%	3.32%	0.03%
Tilos	746	87.61%	0.2%	12.39%	0.03%

, a thorough presentation of the percentage of built-up areas on the Cyclades and Dodecanese islands is provided, distinguishing this between built-up areas inside and outside settlement boundaries and comparing them with the total area of each island. The percentage of built-up areas within settlement boundaries serves as a proxy for settlement density, while the percentage outside settlement boundaries acts as an indicator of urban sprawl. The intensity of urban sprawl varies across the islands studied, reflecting the unique geographic characteristics of each island. This variation highlights the need for spatial planning policies that address urban growth while preserving the islands’ cultural heritage. The bar chart in Figure 4 illustrates these percentages, showcasing the differences in built-up area distribution across the case study example.

For example, Amorgos in the Cyclades shows a pattern with 53.63% of its built-up area within settlements and 46.37% outside, indicating complex spatial development. Islands like Antiparos, Kea, Irakleia, Mykonos, Paros and Patmos have a high percentage of built-up area outside settlements, suggesting uncontrolled development, potentially driven by tourism. These outliers highlight the diverse dynamics of urbanization and land use, influenced by geographical, economic and social factors. In contrast, islands such as Kimolos and Simi show dense urban cores, with a significant share of built-up areas within the official settlement boundaries. Overall, the Dodecanese region generally has a higher percentage of built-up areas within the settlement boundaries, compared to the Cyclades region. The results reveal that six islands (Antiparos, Irakleia, Kea, Mykonos, Paros and Patmos) have substantial rates of built-up areas in exurban areas (over 60%), while several others show similar levels of built-up areas both within and outside settlements.

Although the islands of the South Aegean share several common characteristics related to built-up area dispersion and cultural heritage pressures, they also have important differences. These differences come from factors such as island size, tourism development, land availability and planning regulations. Due to the large number of islands included in this study, a detailed examination of each individual case is beyond this study’s scope. Instead, our analysis highlights regional trends while recognizing that some islands may have unique patterns worth exploring in future research. This comprehensive examination underscores the multifaceted dynamics of urban sprawl across the Aegean islands.

For example, on islands such as Mykonos and Naxos, built-up areas outside settlement boundaries encroach upon archaeological sites and traditional landscapes, disrupting their integrity. This encroachment can lead to irreversible damage, including the loss of archaeological context and challenges in managing tourism flows to these sensitive areas. Additionally, urban sprawl often creates fragmented landscapes, reducing the coherence of traditional settlements and their cultural significance.

Figure 5 illustrates the spatial distribution of selected island examples of the study region, based on the findings presented in Table 2.

Table 3. Impact of built-up areas on cultural heritage sites on the islands of the Southern Aegean, including percentage and number of affected sites. Source: own elaboration.

Effect of Built-Up Areas on the Cultural Heritage Sites on Islands of Southern Aegean Region
Cyclades	Historical %	Historical No.	Archaeological %	Archaeological No.	Monuments %	Monuments No.
Amorgos	-	-	39.34%	23	1.02%	62
Anafi	-	-	23.26%	1	-	4
Andros *	-	-	7.68%	18	1.26%	260
Antiparos	-	-	4.39%	4	1.27%	4
Donousa	-	-	-	3	-	-
Folegandros	-	-	-	-	16.28%	17
Ios	-	-	7.83%	7	1.87%	21
Irakleia	-	-	100%	2	-	1
Kea *	9.82%	1	38.20%	17	0.67%	13
Kimolos *	-	-	24.89%	4	5.33%	10
Kythnos *	-	-	-	5	0.60%	22
Koufonisi	-	1	-	1	-	-
Mykonos	88%	2	99.71%	7	0.03%	34
Milos	-	1	72.49%	12	1.07%	29
Naxos *	60.17%	39	85.66%	13	2.34%	214
Paros	31.25%	2	43.04%	13	0.51%	77
Schoinousa *	-	-	-	1	-	-
Serifos	-	-	87.20%	2	2.77%	18
Sifnos *	14.63%	1	15.16%	6	1.13%	67
Sikinos	-	-	-	-	39.82%	15
Syros	46.70%	3	2.23%	8	0.26%	26
Santorini	49.92%	17	80.68%	4	0.56%	35
Tinos	7.14%	3	8.01%	12	1.32%	45
Dodecanese
Arkoi	-	-	-	2	-	-
Astipalaia	74.77%	1	14.10%	17	-	9
Chalki	-	-	-	5	-	25
Kalimnos *	-	-	4.53%	6	0.59%	29
Karpathos	-	-	48.39%	6	0.19%	34
Kasos	-	-	24.95%	3	8.27%	16
Kos	1.17%	4	39.10%	10	1.17%	76
Leipsoi	-	-	14.23%	4	-	1
Leros *	76.44%	2	57.09%	11	0.34%	15
Nisyros	13.59%	4	15.20%	3	-	19
Patmos	-	-	-	1	2.28%	41
Rhodes	10.53%	7	52.88%	39	6.20%	247
Simi	2%	2	99.80%	6	24.05%	28
Tilos	-	1	7.89%	3	1.16%	59

* Where certain archaeological sites are located in marine areas.

and Figure 6 demonstrate the impact of built-up areas lying outside official boundary delineations on cultural heritage across islands in the Southern Aegean region.

The cultural heritage areas analyzed in this study are strictly those officially designated by the Archaeological Cadaster. This means that our findings pertain only to formally recognized sites and do not consider the broader cultural or socioeconomic aspects of heritage preservation. Consequently, the analysis focuses on spatial relations rather than interpretative or historical dimensions of cultural heritage management.

Cultural heritage is classified into three categories: historical, archaeological and monuments. Each cell in Table 3 represents the percentage of built-up areas affecting each category on each island. For example, on the island of Mykonos, Cyclades island complex region, built-up areas affect 88% of the historical sites, 99.71% of the archaeological sites and 0.03% of monuments.

The percentage of archaeological areas might be slightly lower than the actual figures due to the fact that certain archaeological areas extend into coastal regions, as indicated by an asterisk (*) in Table 3. This applies to islands such as Andros, Kea, Kimolos, Kythnos, Naxos, Schoinousa, Sifnos, Kalimnos and Leros, where certain archaeological sites are located in marine areas.

Table 3 enables a comparison of the impact of built-up areas on cultural heritage across different islands, providing insights into the preservation efforts needed and developmental patterns. Higher percentages indicate a greater impact and potential areas for undertaking cultural heritage protection initiatives, while lower percentages suggest better preservation of cultural heritage.

The results highlight diverse needs for cultural heritage preservation and varying degrees of integration of cultural heritage into the urban context. Unlike prior studies that broadly discuss the conflict between development and heritage conservation, this research quantifies the specific impacts of unregulated development on cultural assets across islands, providing actionable insights for regional planning. Notably, islands like Serifos, Simi and Mykonos have high percentages of historical and archaeological sites, reflecting their rich cultural significance. Additionally, islands such as Santorini and Leros show a remarkable concentration of cultural sites, suggesting the need for careful spatial planning that is capable of balancing developmental and heritage conservation objectives. The bar chart, with green for historical sites, blue for archaeological sites and red for monuments, illustrates these varying impacts and highlights the need for careful urban planning to protect the islands’ cultural heritage.

As mentioned in the previous sections, in this study, the correlation between built-up areas and cultural heritage across islands is explored. This study not only identifies significant correlations between urban growth and cultural heritage impacts but also highlights critical areas where preservation efforts must be prioritized. These findings offer a detailed framework for addressing the global challenge of balancing heritage conservation with development in culturally rich but vulnerable regions. Understanding the relation between these two factors is crucial for spatial planning, conservation efforts and sustainable development.

In

Table 4. Correlation coefficients between built-up areas and cultural heritage across various islands. Source: own elaboration.

Islands	Amorgos	Anafi	Andros	Antiparos	Arkoi
Correlation of cultural heritage with built-up area	0.721	−0.179	0.629	−0.004	NA
Islands	Astipalaia	Chalki	Donousa	Folegandros	Ios
Correlation of cultural heritage with built-up area	0.654	NA	0.751	0.981	0.507
Islands	Irakleia	Kalimnos	Karpathos	Kasos	Kea
Correlation of cultural heritage with built-up area	0.659	−0.332	0.753	−0.125	0.576
Islands	Kimolos	Kythnos	Kos	Koufonisi	Leipsoi
Correlation of cultural heritage with built-up area	NA	0.932	0.844	0.626	−0.195
Islands	Leros	Mykonos	Milos	Naxos	Nisyros
Correlation of cultural heritage with built-up area	0.757	0.805	0.815	0.819	−0.137
Islands	Paros	Patmos	Rhodes	Santorini	Schoinousa
Correlation of cultural heritage with built-up area	0.968	0.826	0.874	0.710	−0.030
Islands	Serifos	Sifnos	Sikinos	Simi	Syros
Correlation cultural heritage with built-up area	−0.273	0.830	0.189	0.757	−0.602
Islands	Tilos	Tinos
Correlation of cultural heritage with built-up area	−0.273	0.894
Strong positive correlation r > 0.7			Weak negative correlation −0.3 < r ≤ 0
Moderate positive correlation 0.3 < r ≤ 0.7			Moderate negative correlation −0.7 < r ≤ −0.3
Weak positive correlation 0 < r ≤ 0.3			Strong negative correlation r < −0.7

NA = Not Applicable.

, correlations calculated using the Pearson correlation coefficient are presented, expressing the linear relation between two variables. In the Pearson equation, the variables Xi and Yi represent the individual data points for “Built-up Area” and “Cultural Heritage” for each specific island. The variables $\overline{\mathrm{X}}$ and $\overline{\mathrm{Y}}$ are the means of “Built-up Area” and “Cultural Heritage”, respectively. The correlation coefficient indicates both the strength and direction of the relation between “Built-up Area” and “Cultural Heritage” for each island. Values closer to 1 or −1 indicate a stronger correlation, while values closer to 0 indicate a weaker correlation.

Using the Pearson correlation coefficient to evaluate the entire Cyclades and Dodecanese regions showed a correlation coefficient of 0.774, indicating a positive relation. This suggests that as built-up areas expand without restrictions, they often encroach upon cultural heritage sites located within protected areas. Consequently, this expansion poses a threat to heritage sites, emphasizing the urgent need for policy initiatives targeting the protection of these invaluable areas from unregulated development. Analyzing the correlation coefficients for each island in the Cyclades and Dodecanese regions reveals distinct relations between cultural heritage and urban growth, more specifically the following:

• Islands such as Folegandros, Tinos and Kythnos exhibit highly positive correlations, indicating a robust connection between cultural significance and built-up areas. This implies that the built-up areas significantly impact the cultural heritage sites, occupying substantial portions of these areas. The unregulated expansion of built space, often beyond official settlement boundaries, threatens these valuable cultural sites.
• Islands like Syros, Kalimnos and Serifos stand out with negative correlations, implying a weak negative relation between cultural heritage areas and built-up areas. This suggests that the built-up areas do not negatively affect the cultural heritage areas on these islands.

Table 4 underscores the importance of tailoring policies to island-specific conditions. For islands with strong positive correlations, strict spatial planning regulations and enhanced monitoring of built-up area dispersion (urban sprawl) are essential. In contrast, for islands with weak or negative correlations, efforts should focus on maintaining existing protections and monitoring for potential future risks.

5. Conclusions

Landscapes are inherently dynamic, evolving over time in response to societal changes. The main factors of this change include natural processes and human activities, such as changes in production techniques, built-up area expansion, tourism infrastructures, transport networks, etc. However, when these changes occur rapidly and without strategic planning, they can lead to significant and often irreversible alterations in landscapes, raising concerns about the preservation of the unique natural and cultural characteristics of a region.

In island regions, this phenomenon is particularly evident due to their fragile socio-spatial systems and the immense pressures exerted by mass tourism. Our findings indicate that uncontrolled urban sprawl poses significant threats to the cultural heritage of the South Aegean islands. Current spatial planning tools are inadequate for protecting archaeological areas and historic sites, primarily due to ongoing pressures from expanding construction activities. Tourism development further intensifies these challenges, leading to built-space expansion that disrupts the cultural landscape.

Tourism, the primary economic driver for the islands, generates demand for infrastructure such hotels and second homes, particularly in areas with high cultural value. This unregulated development often compromises the historical integrity of heritage sites. Seasonal population increases due to tourism exacerbate land-use pressures, driving construction in peripheral and exurban areas.

Urban sprawl is particularly concentrated in coastal zones and areas near cultural landmarks, intensifying development pressures. While this study focuses on spatial analysis, tourism-driven urbanization, second-home expansion and coastalization also play a key role in shaping these trends. However, due to this study’s methodological focus on geospatial datasets, these socioeconomic factors were not quantitatively analyzed. Future research should integrate socioeconomic data to provide a deeper understanding of urban expansion and its impact on cultural heritage areas.

Development often occurs outside settlement boundaries due to several factors. Land outside these boundaries is typically cheaper, lacks urban infrastructure and offers more availability and environmental qualities. Moreover, it is not subject to the institutional regulations that govern land within designated settlements, making it an attractive option for unregulated construction.

The patterns of urban sprawl tend to favor coastal zones and areas near cultural landmarks, fragmenting traditional settlements and encroaching upon heritage sites. Inconsistent spatial planning exacerbates these pressures, as it struggles to balance development with preservation.

The key threats include encroachment on cultural zones, landscape degradation and the loss of traditional settlement character, all of which undermine heritage preservation. Addressing these issues requires a clear understanding of the drivers of urban sprawl and their impact on cultural landscapes.

This study highlights the urgent need for an integrated approach to spatial planning that prioritizes the preservation of cultural heritage alongside sustainable development. While this study highlights common trends in built-up area dispersion and its impact on cultural heritage across the South Aegean, it is important to acknowledge that individual islands may experience these pressures differently. Factors such as tourism intensity, land availability and local planning policies contribute to these variations. Future research could explore island-specific case studies to provide a more detailed understanding of the unique challenges faced by different locations.

Establishing a comprehensive spatial planning framework is essential, incorporating clear guidelines for landscape management and regulations to protect cultural heritage.

To improve the effectiveness of spatial planning and heritage protection policies, it is crucial to strengthen policy implementation and enforcement. Social and economic driving forces often override planning’s ability to regulate space. The General Urban Plans (GUPs and OCSHOPs) appear insufficient to mitigate the local dynamics being created. Improving the spatial planning system should involve action at multiple levels: (a) at the local level, through the implementation of general and special urban plans; (b) at the regional level, by completing and revising regional frameworks; and (c) at the national level, through the completion and revision of special spatial frameworks.

Ensuring the effectiveness of spatial planning requires the establishment and operation of a spatial planning observatory. This observatory would play a critical role in monitoring, evaluating and improving spatial planning practices across all levels of governance.

A significant challenge is the inconsistent application of spatial planning laws, which allows development in protected zones. Policymakers need to improve coordination between various government agencies, local authorities and stakeholders to ensure that regulations are properly enforced and that there is a shared commitment to cultural heritage preservation.

Advanced geoinformatics tools can play a pivotal role in assisting policymakers by enhancing their understanding of spatial dynamics and their implications for cultural heritage. In Greece, ongoing revisions to spatial planning and the development of new frameworks offer a valuable opportunity to address these issues. Future research should focus on the implementation of these tools and frameworks, exploring innovative methods for landscape management that effectively integrate cultural preservation with development goals.

Policymakers and stakeholders must recognize the delicate balance between preserving cultural heritage and fostering tourism development in island contexts. The pressures of mass tourism and unregulated growth can alter landscapes and threaten the integrity of cultural resources, endangering sustainability objectives and the viability of the tourism sector. By prioritizing strategic planning and thoughtful management, it is possible to safeguard the rich cultural heritage of these islands while promoting sustainable development objectives. Implementing a balanced approach will ensure that both cultural heritage and economic growth can coexist harmoniously, to the benefit of both current and future generations.

Importantly, this study introduces a quantitative framework for heritage protection, offering an innovative approach that can be applied globally. While this research is based on the specific context of the Southern Aegean islands, the methodology and findings are relevant to any region facing the pressures of urbanization and cultural heritage conservation. The framework developed in this study provides a valuable tool for local, regional and international policymakers, enabling the creation of more effective spatial planning strategies that balance cultural heritage preservation with necessary development. This work sets a model for the sustainable management of urban expansion in culturally sensitive areas worldwide, offering a foundation for future research and policy efforts in regions facing similar challenges.