Long-term protection of arid ecosystems changes the vegetation and soil structures. The quantification of aboveground biomass and carbon content are among the principal indicators to evaluate these changes. Most methods used to quantify these parameters are costly, time consuming and destructive. In this paper, two non-destructive methods were compared: digital image processing and biometric measurements. Aboveground biomass and carbon content of five perennial shrubs were studied inside and outside Sidi Toui National Park, southern Tunisia. The effect of long-term protection on aboveground biomass and carbon content was assessed. The main results indicated that both methods provided similar aboveground biomass and carbon values. Aboveground biomass and carbon content were strongly correlated with canopy cover and biovolume (R² ˃ 0.7). Positive linear relationships were found for all the studied species. Apart from the large canopy cover of Haloxylon schmittianum and Haloxylon scoparium, the obtained results showed that long-term protection had no significant effect on aboveground biomass and carbon content for the other species. These results suggest that digital charting technique is an accurate method for assessing rangeland productivity in a timely and cost-efficient manner and that long-term protection is not always suitable for enhancing carbon content and therefore ecosystem resilience under climate change conditions.

干旱生态系统的长期保护改变了植被和土壤结构。地上生物量和碳含量的量化是评估这些变化的主要指标之一。大多数用于量化这些参数的方法成本高昂、耗时且具有破坏性。在本文中，比较了两种无损方法：数字图像处理和生物特征测量。研究了突尼斯南部 Sidi Toui 国家公园内外五种多年生灌木的地上生物量和碳含量。评估了长期保护对地上生物量和碳含量的影响。主要结果表明，两种方法提供了相似的地上生物量和碳值。地上生物量和碳含量与冠层盖度和生物量密切相关（R ² ˃ 0.7)。所有研究的物种都发现了正线性关系。除了梭梭和梭梭的冠层覆盖大外，所得结果表明，长期保护对其他物种的地上生物量和碳含量没有显着影响。这些结果表明，数字制图技术是一种及时、经济高效地评估牧场生产力的准确方法，长期保护并不总是适合提高碳含量，从而提高气候变化条件下的生态系统弹性。