Prof. Joan Iliopoulou - Georgudaki Sustainable planning and management of recreational caves under ecological capacity constraints: a case study Prof. Joan Iliopoulou - Georgudaki

Caves and sustainable planning Caves comprise natural heritage, sharing common threats from the human presence with those provoked to the cultural heritage As a result, similar tools are utilized for sustainable planning and management of recreational caves, such as “carrying capacity”, “limits of acceptable changes” etc. The caves as recreational places attract annually numerous visitors and can be regarded as significant sources of income and an important factor to local development Previous research has revealed the great variety of biotopes and organisms, which inhabit caves

Case study: The cave of Perama Located at the Region of Epirus nearby the city of Ioannina in NW Greece

Aim of the study Ecological quality assessment of the cave Preservation of the cave’s climatic stability Preservation of the cave’s physicochemical factors Protection of the cave’s fauna Estimation of the Cave’s recreational carrying capacity Estimation of threats: Estimated number of visitors / given actual number of visitors

Materials and methods For a period of one year Study of the flora and fauna of the cave CO2 concentrations before and after the visit of numerous tourists Relative humidity, temperature, wind speed, wind direction, speed and air renovation Finally estimation of the cave’s recreational carrying capacity mass of produced vapour of water the volume of produced CO2 and consumed O2 from the maximum number of visitors allowed

Flora and fauna of the cave From the entrance to the artificial exit, especially around the illuminated areas, the cave is colonized by photosynthetic microorganisms. 29 species of cyanobacteria, 3 species of chlorophytes, diatoms, mosses and mosses protonemata were found on soil samples Fauna

CO2 concentrations 24 sample sites selected from throughout the cave (the distance of the route between entrance and exit) Samples were received between 8.30 – 11.00 (50 visitors), 15.00 – 17.00 (100 visitors) and 20.00 – 21.00 (no visitor)

CO2 concentrations An increase of CO2 is depicted from the entrance (sample 1) to the exit (sample 24) on the passage of 163 steps of the cave (the height difference between the entrance and the exit is 65m)

Relative humidity Temperature

Determining the air exchange time The volume of the cave in areas A and B is calculated (being 28000m3 and 3300m3 respectively). Mean wind velocity in the access point is 0.23m/sec (area A) and 0.12m/sec (area B) respectively, while the surface of the cross section is 1.54m2 and 2.32m2 respectively The mean air supply is 0.35 m3/sec (A) and 0.28m3/sec (B) As a result, it takes 22 and 3,5 hours to renovate the air in areas A and B respectively

Determining the maximum allowed number of visitors N = cVT / Qt, where c is the specific heat of the air, V is the volume of the area, Q is the produced heat per visitor and per unit time, t the time spent in the area and T the maximum acceptable temperature increase

Air intake and CO2 and H2O produced For usual air intake (8 l/min) each visitor consumes 0.39l/min O2 and produces 0.33l/min CO2 and 0.32g/min H2O For the maximum visitors allowed, spending the standard time the total number of mass or volume is O2 (l) CO2 (l) H2O (g) Area A 991 838 813 Area B 73 61 60

According to the formula e = ρw * R/Mw * T, where e is the partial pressure, ρw is the water vapour density and R is the perfect gas constant, Mw is the molecular weight of water vapour and T is the absolute temperature of the cave the quantity of the vapor necessary to saturate the air is 0.11g/m3 For area A the mass of vapour necessary to saturate the air is 0.11x28000 = 3080g and for area B 0.11x3300 = 363g Neither the production of CO2 nor the production of water vapour poses a limit on the number of visitors Taking into account all data above, 30 people every 15 minutes do not stress the environment of the cave

Conclusions The calculation of the carrying capacity and the limits of acceptable changes regarding the physicochemical parameters permitted the estimation of the cave’s recreational carrying capacity The planning authorities, according to the above, can concern alternatives to redistribution and rationing recreation as the access to the cave is restricted by fees at the cave’s sole entrance, and there is excess demand during certain times of the year

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