Evaluating the Ecologigical Integrity of a Tropical Lake Using Community Degradation Index

Öz

This study evaluated the ecological integrity of Stratum VII (Yeji sector) of Lake Volta, Ghana, using fish-based indicators, specifically diversity indices and the Community Degradation Index (CDI). Fish samples were collected from four fishing communities, namely; Fante Akura, Brekente, Tonka, and Vutideke between January and December, 2024. A total of 41 species belonging to 13 families were recorded, with Chrysichthys walkeri (39.46%), Chrysichthys nigrodigitatus (13.76%), and Schilbe mystus (13.12%) as the most dominant species, reflecting the resilience of opportunistic taxa. Diversity analysis showed healthy ecological environment at Stratum VII, with Shannon–Wiener index values ranging from 1.98 (Fante Akura) to 3.27 (Vutideke). The CDI values ranged from 1.10 (Vutideke) to 5.29 (Fante Akura), suggesting that despite existing anthropogenic stress, Stratum VII has not yet reached critical degradation level. Generally, CDI provided a more robust assessment by accounting for trophic interactions and species resilience, offering deeper insights into ecosystem degradation. Therefore, this study emphasizes the importance of integrating functional indices with conventional diversity measures in monitoring frameworks to inform sustainable management of Lake Volta and similar inland freshwater ecosystems in Ghana.

Anahtar Kelimeler

• Lake Volta
• Ghana
• Shannon–Wiener Index
• Species Composition
• Freshwater fishes

Topluluk Bozulma Indeksi Kullanarak Tropikal Bir Gölün Ekolojik Bütünlüğünün Değerlendirilmesi

Öz

Bu çalışmada, Volta Gölü’nün Stratum VII (Yeji sektörü) bölgesinin ekolojik bütünlüğü, özellikle çeşitlilik indeksleri ve Topluluk Bozulma İndeksi (CDI) gibi balık-temelli göstergeler kullanarak değerlendirmiştir. Balık örnekleri, Ocak–Aralık 2024 tarihleri arasında dört bölgeden, Fante Akura, Brekente, Tonka ve Vutideke toplanmıştır. Toplamda 13 familyaya ait 41 tür kaydedilmiş olup, fırsatçı taksonların dayanıklılığını yansıtacak şekilde Chrysichthys walkeri (%39,46), Chrysichthys nigrodigitatus (%13,76) ve Schilbe mystus (%13,12) türleri en baskın türler olarak belirlenmiştir. Çeşitlilik analizleri, stratum VII’de sağlıklı bir ekolojik ortam olduğunu göstermiş olup, Shannon–Wiener indeks değerlerinin Fante Akura’da 1.98 Vutideke’de 3.27 arasında değiştiğini göstermiştir. Vutideke’de 1,10 ile Fante Akura’da 5,29 arasında değişen CDI değerleri halihazırda antropojenik stresi işaret etmekle beraber, stratum VII kritik bozulma eşiğine henüz ulaşmamıştır. CDI, trofik etkileşimleri ve türlerin dayanıklılığını da hesaba katarak daha kapsamlı bir değerlendirme sunarak ekosistem bozulmasına dair daha derinlemesine içgörüler sağlamıştır. Bu nedenle bu çalışma, Gana’daki Volta Gölü ve benzer içsu ekosistemlerinin sürdürülebilir yönetimini desteklemek amacıyla, izleme çalışmaları kapsamında işlevsel indekslerin geleneksel çeşitlilik ölçütleriyle birlikte kullanılmasının önemini vurgulamaktadır.

Anahtar Kelimeler

• Volta Gölü
• Gana
• Shannon–Wiener Endeksi
• Tür Kompozisyonu
• Tatlı su balıkları

Kaynakça

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