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

2. 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

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

4. 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

5. 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

6. 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

7. 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 – (50 visitors), – (100 visitors) and – (no visitor)

8. 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)

9. Relative humidity
Temperature

10. Determining the air exchange time
The volume of the cave in areas A and B is calculated (being m3 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

11. 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

12. 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

13. 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

14. 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

15. Thank you for your attention…