IPRC - 2015

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Institutional robustness averts Hardin’s tragedy of the commons in the community-based beach seine fisheries in Sri Lanka
(Faculty of Graduate Studies, University of Kelaniya, 2015) Deepananda, K.H.M.A.; Amarasinghe, U.S.; Jayasinghe-Mudalige, U.K.
Small scale coastal fisheries accounts for nearly 40% of world fish catches and provide direct employment for more than 90% of the world fishers employed in capture fisheries. Subsequent recognition of the failures of centralized fisheries management led the governments to accept community-based management as an invaluable means to formulate fisheries management. Such traditional management practices exist in beach seine fisheries of Sri Lanka. Study ascertains and documents the rules and norms that are in general not formerly codified in writing, and evaluate empirically the compliance of elements of customary governance with Ostrom‘s modified design principles (MDP) for long enduring commons management systems. Eight beach seine fisher communities were studied using standard ethnographic methods, and evaluation of compliance with MDP was carried out by administering structured questionnaires. Fishing rights in contiguous sea were vested to the villagers who lived in the sea front, as a residential proximity right. Due to this tradition, the ownership of a beach seine and fishing rights came in three ways identified as: exclusive right, primary rights and secondary right. Sole authority for governing the commons was vested to community organization termed ―madelsamithi‖, considered as the local administrative unit. Institution governing the commons addressed the excludability problem by defining fishing territory, eligibility rules and intercommunity access rule, while subtractability problem was addressed by gear rules, temporal allocation rules, first comer rules, fishing behaviour rules, conservation rules, and rules for distribution of benefits. Institutional architecture of beach seine fisher communities exhibited the high compliance with MDP. Out of the 11 MDP, fisher communities showed very high compliance with four MDP and high compliance with six MDP. Only one MDP had a lower level compliance. As empirical evaluation on architecture of customary institutions shows high compliance with MDP, beach seine fisher communities can be treated as those govern commons through selfgoverning institutions. Beach seining in southern Sri Lanka is, therefore an example for wellmanaged commons that relies on strong, locally crafted rules as well as evolved norms, where institutional and governance mechanisms have essentially averted the ―tragedy of the commons‖. Study provides the starkness to the notion that local actors in tropical communitybased marine resource systems overcome the tragedy of the commons through robust selfgoverning institutions.
Seasonal water level fluctuation, habitat alteration and colonization of marginal benthic fauna in irrigation reservoirs in the Kala Oya River basin in Sri Lanka
(Faculty of Graduate Studies, University of Kelaniya, 2015) Weerakoon, S.N.; Chandrasekara, W.U.; Amarasinghe, U.S.
The innumerable benthic microhabitats in freshwater ecosystems support a wide variety of fauna. These benthic fauna are sensitive to natural as well as anthropogenic disturbance events such as water level fluctuations, temperature variations, agrochemical inputs etc. The present study was carried out to investigate the effect of seasonal water level fluctuation on the distribution and colonization of benthic fauna at some irrigation reservoirs in Sri Lanka. The study was carried at 10 reservoirs namely Angamuwa wewa, Balalu wewa, Dewahuwa wewa, Ibbankatuwa wewa, Kandalama wewa, Katiyawa wewa, Kala wewa, Siyambalangamuwa wewa, and Usgala-Siyambalangamuwa wewa in the Kala Oya river basin in Sri Lanka. The study period (September, 2014 to March 2015) included a dry season followed by a rainy season. Soil core samples (n = 15, volume = 0.5 dm3 each) from within 3 random locations in the marginal zone of each reservoir at each season were collected using a soil corer. After the samples were wet sieved in situ through a 1 mm sieve, the macrobenthic fauna in each sample were separated, identified to the nearest possible taxonomic level and enumerated separately. Environmental parameters such as aquatic vegetation, shadiness, soil texture, soil pH and the degree of water inundation were also measured using standard methods. The Shannon-Wiener diversity index for each reservoir for the two climatic seasons were determined and were statistically compared by a t-test. The abundance of benthic species at different study sites were analyzed using cluster analysis. The importance of environmental variables on the abundance of macrobenthos for both seasons were tested by the Principal Component Analysis (PCA). Altogether 17 taxa were recorded. Bellamya (Mystery snail) (62.2 ± 17.2) and Melanoides (Trumpet snail) (38.5 ± 11.6) were the dominant taxa during the dry season while Bithynia (Mud snail) (15.77 ± 6.75) and Bellamya (4.83 ± 1.38) dominated during the rainy season. The species richness was higher in rainy season (17 taxa) than in the dry season (11 taxa). This was due to the presence of six additional taxa i.e. Chironomidae, Oligocheata, Ephemeroptera, Trematoda, Zygoptera and Bithynia) during the rainy season. The species diversity of the reservoirs was significantly high during the rainy season (t – test, P = 6.2148, α = 0.05, df = 22). PCA revealed that the degree of water inundation and aquatic vegetation to be the key factors that determine the species distribution of these reservoirs. The elevated species diversity perhaps may be due to the enhanced growth of aquatic vegetation at the shallow marginal habitats when the reservoirs were inundated by water during the rainy season. The change of this habitat alteration may have positively supported the colonization of new insect taxa such as Chironomids, Ephemeropterans and Zygopterans into these shallow marginal habitats of irrigation reservoirs in the Kala Oya River Basin in Sri Lanka.