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Speaker

Authors

Timothy O’Connor –

Abstract

Southern hemisphere mountain ecosystems are not as well represented on the global research stage as northern hemisphere mountain ecosystems are. As a result, southern hemisphere mountain systems are often less well understood, and, therefore, often prone to assumptions for management and mitigation biased to northern hemisphere perspectives. For example, the absence of a clear treeline in these grassland-dominated systems often masks the effects of climate change compared to typical northern hemisphere systems that can monitor the upward movement of trees and shrubs and correlate this to thermal changes. Also, the natural role of fire in these semi-arid and drought-prone southern systems drives a biodiversity suite that is very different in ecology and life strategy to those in northern systems. Thus, different means of measuring and monitoring change in grass-dominated southern hemisphere mountains are necessary. We use the endemic-rich Maloti-Drakensberg mountains as a case in point to show the potential for measuring change through: (1) considering the masking effects of immediate anthropogenic change (usually a more dramatic and immediate concern in real-time), and (2) considering background subtle change. For the latter, we explore potential indicators such as biodiversity erosion, species composition shifts, C3-C4 grass community changes, woody species expansion, and colonisation by non-native species (invasive and naturalised). Challenges to these indicators being effective are the masking effects of immediate change and the gradual erosion of ecosystem resilience from long periods of unsustainable use (e.g. communal rangeland degradation since the 1800s). Given the extremely high water production value of these mountains in arid and semi-arid southern Africa, the long-term resilience of such ecosystems should be a high priority for research, policy and practice.

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