Nijerya'nın Ondo Eyaletindeki Üç Koruma Alanının Mevcut Durumunun Değerlendirilmesi: Temel Durum Tespit Çalışması

Öz

Koruma alanlarının kutsallığını korumak ve ekosistem hizmetlerinin sürekliliğini sağlamak için bu alanların düzenli olarak değerlendirilmesi hayati önem taşımaktadır. Yağmur ormanı koruma alanlarında (PA’lar) insan kaynaklı faaliyetler ve baskılar, habitatların bozulmasına ve flora ile faunanın kaybına yol açmıştır. Nijerya’nın Ondo Eyaletindeki koruma alanlarının çoğu, pervasızca sömürülmüş, gasp edilmiş ve başka arazi kullanımlarına dönüştürülmüştür. Bu çalışma, sürdürülebilir yönetim için temel bilgiler sağlamak ve acil koruma gerektiren nadir ve tehdit altındaki türleri belirlemek amacıyla Ondo Eyaletindeki üç koruma alanını değerlendirmiştir. Çalışma, Akure-Ofosu Orman Rezervi (Ondo Merkez), Osse Nehri Parkı (Ondo Kuzey) ve Oluwa Orman Rezervi (Ondo Güney) genelinde ağaç türlerinin çeşitliliğini, bolluğunu ve büyüme değişkenlerini değerlendirmiştir. Veriler, 250 m aralıklarla 50 × 50 m'lik parsellerden oluşan sistematik hat kesitleri kullanılarak toplanmıştır. Çapı 10 cm ve üzeri olan tüm ağaçlar tespit edildi, ölçüldü ve kaydedildi. Hektar başına ortalama taban alanı ve hacim, Oluwa’da en yüksek seviyedeydi (288,90 m² ha⁻¹; 2897,12 m³ ha⁻¹) en yüksek değerlere sahipti; bunu Akure-Ofosu (222,59 m² ha⁻¹; 1710,90 m³ ha⁻¹) ve Osse (101,91 m² ha⁻¹; 1004,55 m³ ha⁻¹) izledi. Biyoçeşitlilik indeksleri, Pielou'nun eşitlik indeksinin Akure-Ofosu'da (1,05) en yüksek olduğunu, Shannon-Wiener (H’) indeksinin burada 4,24 ile zirveye ulaştığını ve Margalef'in zenginlik indeksinin Oluwa'da (13,66) en yüksek olduğunu gösterdi. Simpson indeksi tüm alanlarda 0,93'ü aştı. Özellikle Sterculiaceae, Combretaceae, Ulmaceae, Apocynaceae, Caesalpiniodeae ve Verbenaceae en tür açısından zengin familyalardı ve Oluwa üstün yapısal karmaşıklık ve çeşitlilik sergiledi. Çalışma, uzun vadeli orman ekosistemi sürdürülebilirliğini sağlamak için koruma alanları yönetmeliklerinin sıkı bir şekilde uygulanmasını, tehdit altındaki türlerin hedefli bir şekilde korunmasını ve yerel topluluklar için alternatif geçim kaynaklarının geliştirilmesini önermektedir.

Anahtar Kelimeler

• Biyoçeşitlilik değerlendirmesi
• ormansızlaşma
• ekosistem yönetimi
• orman koruma
• koruma alanları

Assessment of the Present Status of Three Protected Areas on Ondo State, Nigeria: A Baseline Study

Abstract

Regular assessment of protected areas is essential for preserving their sanctity and ensuring continuous ecosystem services. Anthropogenic activities and pressure in rainforest protected areas (PAs) have caused habitat degradation and loss of flora and fauna. Most PAs in Ondo State, Nigeria have been recklessly exploited, hijacked, and converted to other land uses. This study assessed three PAs in Ondo State to provide baseline information for sustainable management and identify rare and threatened species requir-ing urgent conservation. The study evaluated tree species diversity, abundance, and growth variables across Akure-Ofosu Forest Reserve (Ondo Central), Osse River Park (Ondo North), and Oluwa Forest Reserve (Ondo South). Data were collected using systematic line transects with 50 × 50 m plots at 250 m intervals. All trees ≥10 cm DBH were identified, measured, and recorded. Mean basal area and volume per hectare were highest at Oluwa (288.90 m² ha⁻¹; 2897.12 m³ ha⁻¹), followed by Akure-Ofosu (222.59 m² ha⁻¹; 1710.90 m³ ha⁻¹) and Osse (101.91 m² ha⁻¹; 1004.55 m³ ha⁻¹). Biodiversity indices showed Pielou's evenness was highest in Akure-Ofosu (1.05), Shannon-Wiener (H’) peaked at 4.24 there, and Margalef's richness was greatest at Oluwa (13.66). Simpson's index exceeded 0.93 across all sites. Notably, Stercu-liaceae, Combretaceae, Ulmaceae, Apocynaceae, Caesalpiniodeae, and Verbenaceae were the most species-rich families, with Oluwa showing superior structural complexity and diversity. The study recommends strict enforcement of PA regulations, targeted protection of threatened species, and developing alternative livelihoods for local communities to ensure long-term forest ecosystem sustainability.

Keywords

• Biodiversity assessment
• deforestation
• ecosystem management
• forest conservation
• protected areas

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