Proposed mechanism for the origin of sodic patches in Kruger National Park, South Africa
Proposed mechanism for the origin of sodic patches in Kruger National Park, South Africa
复制标题
南非克鲁格国家公园钠质斑块起源的拟议机制
DOI：
10.1111/j.1365-2028.2004.00532.x
复制
发表时间：
2005
影响因子：
1
通讯作者：
K. Rogers
中科院分区：
文献类型：
--
作者：
L. Khomo;K. Rogers
在半干旱的南部非洲，钠在花岗岩链的山麓斜坡上的积累导致了钠斑的形成。苏打斑块在生态学上对于养分积累、捕食者逃避和打滚具有重要意义，但由于植被剥蚀和美学质量低下，它们往往被视为荒漠化土地。生态学家和游客的这种负面看法往往导致不明智的管理和“恢复”措施。在克鲁格国家公园，苏打补丁发生在河岸高地边界，因此，起源于这两个系统的过程可能有助于他们的起源。高地为基础的连锁和河岸为基础的蒸散模型被用来探讨假设，这些土壤来源于连锁和蒸散驱动的水力过程。该模型预测的植被地带性所决定的耐盐梯度和随着时间的推移，由于渐进的盐积累的结果，在钠斑面积的增加。植被结构和山坡形态横跨河岸高地边界和分析斑块配置的变化超过50年的航空摄影记录来检验的假设。苏打斑块具有独特的植被，出现在山坡的中间位置，面积在50年内增加了三倍，并正在侵入河岸带。这种行为是一致的断言，这些补丁来自连锁和蒸散过程。结果意味着一个动态方面的钠质斑块，这是以前被视为静态景观特征成壤时间尺度。然而，我们表明，他们改变相对较小的时间尺度，这意味着他们的管理应该与这种动态的性质相称。因此，应根据一项计划管理苏打斑块，该计划将其小规模扩张纳入其中，并认识到其生态重要性。
The accumulation of sodium on the footslopes of granitic catenas in semi-arid southern Africa leads to the formation of sodic patches. Sodic patches are ecologically important for nutrient accumulation, predator evasion and wallowing, but they are often perceived as derelict lands because of vegetation denudation and low aesthetic quality. This negative perception, by both ecologists and tourists, often leads to ill-advised management and ‘rehabilitation’ measures. In Kruger National Park, sodic patches occur at the riparian-upland boundary and hence the processes originating in both systems may contribute to their origin. The upland-based catena and riparian-based evapotranspiration models were used to explore the hypothesis that these soils originate from both catena and evapotranspiration-driven hydraulic processes. The models predict vegetation zonation dictated by a salt tolerance gradient and an increase in sodic patch area over time as a result of progressive salt accumulation. Vegetation structure and hillslope morphology across the riparian-upland boundary and analysis of change in patch configuration over a 50-year aerial photographic record were used to test the hypotheses. Sodic patches have unique vegetation, occur on the intermediate positions of hillslopes, have increased in area three-fold over 50 years and are encroaching into the riparian zone. This behaviour is consistent with the assertion that these patches originate from both catena and evapotranspiration processes. Results imply a dynamic aspect of sodic patches, which have been previously viewed as static landscape features in pedogenic time scales. However, we show that they change over relatively smaller time scales meaning that their management should be commensurate with this dynamic nature. Therefore, sodic patches should be managed under a scheme that incorporates their small-scale expansion and recognizes their ecological importance.