Abstract Exclosure management is becoming a common approach to rehabilitate and increase net biomass productivity of extremely degraded areas in Northern Ethiopia. However, the effect of age of exclosures on vegetation and soil property of communal lands is not yet well studied. In this study, the effect of land exclusion and age of exclosure on plant species richness, diversity, density and dominance, herbaceous standing biomass, woody biomass, woody biomass carbon, soil organic carbon (SOC) and other soil properties were assessed. To study the above listed variables, exclosures in three age classes (5–7, 12–15 and >20 years) and adjacent free grazing areas were selected. We replicate each age class three times considering agroecological similarity. From each exclosure and free grazing area, six larger plots (10m × 20m) each having five small quadrats were taken. Totally, 72 larger plots and 360 small quadrats were sampled. The result of this study indicates that exclusion of communal lands significantly improved species richness, diversity, biomass, woody biomass carbon, SOC, total nitrogen (TN) and total potassium (TK). Similarly, the density of perennial species and the density of grass species were found increased with the age of exclosure. Herbaceous species richness, diversity and annual species density were higher in the young-aged exclosures than in the older exclosures. Woody species richness, diversity, density, biomass, and woody biomass carbon were highest in the older exclosures. Besides, age of exclosure increases the content of SOC, TN and TK. Furthermore, it was found that the old-aged exclosures stored more biomass carbon (267 %) and SOC (37.66 %) than the young-aged exclosures. The study indicates the benefits of land exclosure for permanent carbon storage, which is vital to reduce atmospheric greenhouse gas concentration.

中文翻译：

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埃塞俄比亚北部社区管理的围场时代的碳固存和植被特性

摘要 围栏管理正在成为埃塞俄比亚北部极度退化地区恢复和提高净生物量生产力的常用方法。然而，围垦年龄对公共土地植被和土壤性质的影响尚未得到很好的研究。本研究评估了土地开垦和开垦年龄对植物物种丰富度、多样性、密度和优势度、草本生物量、木本生物量、木本生物量碳、土壤有机碳 (SOC) 和其他土壤性质的影响。为了研究上面列出的变量，选择了三个年龄段（5-7、12-15 和 >20 岁）和相邻的自由放牧区的围栏。考虑到农业生态学的相似性，我们将每个年龄组复制了三次。从每个围场和自由放牧区，取了六个较大的地块（10m × 20m），每个地块都有五个小样方。总共采样了 72 个较大的地块和 360 个小样方。本研究的结果表明，排除公共土地显着提高了物种丰富度、多样性、生物量、木质生物量碳、SOC、总氮 (TN) 和总钾 (TK)。同样，多年生物种的密度和草物种的密度随着开垦年龄的增加而增加。幼龄围场的草本物种丰富度、多样性和年度物种密度高于老围场。木本物种丰富度、多样性、密度、生物量和木本生物量碳在较老的围场中最高。此外，外露龄期增加了SOC、TN和TK的含量。此外，发现老年围栏比年轻围栏储存了更多的生物量碳 (267%) 和 SOC (37.66%)。该研究表明土地开垦对永久碳储存的好处，这对于降低大气温室气体浓度至关重要。