Net Primary Productivity (NPP) is an index for assessing ecosystem services and productivity on land. However, previous studies focused solely on NPP changes across ecological regions, overlooking the comparative advantage of the impacts of land changes and climatic variations on various forms of NPP as indicators of ecosystem degradation and restoration across different eco-political milieux. This study comparatively analyzed land cover changes and examined NPP trends and their effects using Mann-Kendall Theil-Sen slopes, the Pearson correlation, and advanced geostatistical methods in the Lake Chad Basin (LCB) and the Aral Sea Basin (ASB). We found that from 2000 to the present and projected to 2030, cropland is expected to expand by 2.20 %, leading to a reduction of shrubland by −2.40 % in LCB. Likewise, a probable increase of 1.1 % in grassland is expected to further reduce waterbodies in ASB by −1.5 %. These potential changes are the resultant effect of the present human-induced NPP (HNPP) reduction of −5.92gC/m2/yr across 2.44 × 103 km2 and 29.84gC/m2/yr across 14.32× 103 km2, indicating human-dominated degradation (HDD) in LCB. Whereas, in ASB, the influence of HNPP by −8.12 gC/m2/yr across 14.32 × 103 km2 and by 4.00gC/m2/yr across 7.24× 103 km2 indicate incipient human-dominated restoration scenarios. Consequent to the warming temperature, climate fluctuations are characterized by HDD in LCB, whereas in ASB, they are characterized by climate-induced degradation. Apprehending these evolving dynamics in endorheic lakes can provide insight into potential restoration trajectories for future land degradations.

中文翻译：

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土地变化和气候变异对干旱地区生态系统净初级生产力的综合影响


净初级生产力 （NPP） 是评估陆地生态系统服务和生产力的指数。然而，以前的研究只关注不同生态区域的 NPP 变化，而忽视了土地变化和气候变化对各种形式的 NPP 影响作为不同生态政治环境中生态系统退化和恢复指标的比较优势。本研究比较分析了乍得湖盆地 （LCB） 和咸海盆地 （ASB） 的土地覆盖变化，并使用 Mann-Kendall Theil-Sen 坡、皮尔逊相关性和高级地统计方法研究了 NPP 趋势及其影响。我们发现，从 2000 年到现在，预计到 2030 年，农田将扩大 2.20%，导致 LCB 的灌木丛减少 -2.40%。同样，草原可能增加 1.1% 预计将使 ASB 中的水体进一步减少 -1.5%。这些潜在变化是目前人为诱导的 NPP （HNPP） 在 2.44 × 103 km2 上减少 -5.92gC/m2/yr 和 在 14.32× 103 km2 上减少 29.84gC/m2/yr 的结果效应，表明 LCB 中人为主导的降解 （HDD）。而在 ASB 中，HNPP 在 14.32 × 103 km2 范围内的影响为 -8.12 gC/m2/yr，在 7.24× 103 km2 范围内的影响为 4.00gC/m2/yr，表明人类主导的恢复情景处于初期。由于温度升高，气候波动以 LCB 中的 HDD 为特征，而在 ASB 中，它们以气候诱导的退化为特征。了解内流湖中这些不断变化的动态可以深入了解未来土地退化的潜在恢复轨迹。