Plant community structure and possible vegetation changes after drought on a granite catena in the Kruger National Park, South Africa

Aardt, Andri C. van; Codron, Daryl; Theron, E J; Preez, P.J. du

doi:10.4102/koedoe.v62i2.1585

Cited by 10 publications

(6 citation statements)

References 22 publications

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“…Acacia nilotica is common on the lower slopes and Euclea divinorium has an association with the duplex sodic soils of the midslopes, whilst Terminalia sericea predominate the crests. More detailed descriptions of the vegetation along the catena are provided in Janecke (2020), Theron et al (2020) and Van Aardt et al (2020).…”

Section: Boreholementioning

confidence: 99%

Groundwater–surface water interactions in an ephemeral savanna catchment, Kruger National Park

Riddell

Nel

Tol

et al. 2020

Koedoe

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The semi-arid conditions in savanna landscapes ensure that ephemeral drainage dominates the hydrological network in these dryland systems. Quantification of their hydrological processes is important to inform ecosystem understanding and future conservation efforts under a changing climate, and to provide guidance for restoration. By combining in situ hydrometric observations, hydrochemistry, remote sensing and a soil water balance model, we characterise the groundwater–surface water interactions in ephemeral low-order catchments of the granitoid regions of the southern Kruger National Park (KNP). Streams at the lowest orders are augmented by lateral interflows from the catena, although the second- and third-order stream reaches are conduits for groundwater recharge to the fractured rock aquifer; the soils of the crests and foot-slopes also show preferential flow, and are truly recharge soils, whilst the duplex soils of the midslopes clearly show their responsive nature to a low soil moisture deficit in the shallow horizons. Actual evaporation (aET) differed between catena elements with surprisingly little variation at third-order hillslopes, with the greatest overall aET at the first order. Meanwhile, soil water balances demonstrated a significant variation in storage of the riparian zones as a result of interflow from upslope and aET losses. Furthermore, data support broader-scale observations that groundwater recharge through the vadose zone to the fractured rock aquifer is dependent upon threshold antecedent precipitation conditions. Moderate precipitation events (5 mm/day – 35 mm/day) over a 2–3 week period initiate groundwater responses with a 2–3 month lag, whilst intense precipitation events (100 mm/day) are expressed within 2–3 weeks.Conservation implications: Understanding the lateral connectivity of terrestrial ecosystems to the ephemeral drainage network expressed via hydrological processes in these savanna landscapes is important to infer potential impacts of climate variability on the continued conservation of these ecosystems, both within and external to protected areas.

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Section: Boreholementioning

confidence: 99%

Groundwater–surface water interactions in an ephemeral savanna catchment, Kruger National Park

Riddell

Nel

Tol

et al. 2020

Koedoe

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“…Drought is characterized as prolonged and extreme below average water availability relative to local mean annual precipitation that extends into one or more wet seasons (Sankaran, 2019) and multi‐annual droughts have been shown to occur periodically in savanna ecosystems—especially semi‐arid ones (Mason and Tyson, 2000, Tyson et al, 2002). Drought has been observed to cause mortality and dieback within juvenile and adult tree communities (Case et al, 2019, Fensham et al, 2009, Sankaran, 2019) and reductions in plant species richness (van Aardt et al, 2020, Sankaran, 2019). Tree mortality was reported in the 2014–2016 drought in the Nkuhlu area, near Skukuza, in the Kruger National Park in South Africa (Case et al, 2019), and also recorded in savannas of north‐eastern Australia post the “millennium” drought (Fensham et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Drought and fire determine juvenile and adult woody diversity and dominance in a semi‐arid African savanna

et al. 2022

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Central to understanding the persistence and dynamics of savanna ecosystems are processes of recruitment and mortality (Bond, 2008). Savanna ecosystems are characterized by demographic bottleneckswhere juvenile trees and shrubs are "trapped" in small size classes by fire and browsing (Bond et al., 2017). In African savanna ecosystems, the prevalence of fire and herbivory shapes both demography and community composition as species unable to tolerate these disturbances are either unable to establish seedlings from seeds, further recruit as saplings from seedlings or are filtered from the ecosystem via mortality (Hoffmann et al., 2012). In absence of fire and herbivory,

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“…These changes could not be seen in the richness and diversity of plants in these mentioned zones. Changes in the riparian areas were, however, not that clear and can be ascribed to the possible hydraulic lift from deeper soil layers, decreasing the impact of the drought (Van Aardt et al 2020). The visible changes in the community compositions over the 2015-2018 period could possibly indicate that the granite catena is a relatively resilient ecosystem in terms of abiotic factors affecting the biotic factors.…”

Section: Severe Drought Of 2015-2016mentioning

confidence: 97%

“…Smit & Bond 2020. As such, an opportunity arose to study how the vegetation on the catena would recover after the drought (Van Aardt et al 2020). The vegetation at the study site was therefore surveyed in the growing seasons of 2015 (beginning of drought) to 2018 (post-drought).…”

Section: Study Area and Surveysmentioning

confidence: 99%

Biotic and abiotic connections on a granitic catena: Framework for multidisciplinary research

Janecke

Tol

Smit

et al. 2020

KOEDOE - African Protected Area Conservation and Science

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Plant community structure and possible vegetation changes after drought on a granite catena in the Kruger National Park, South Africa

Cited by 10 publications

References 22 publications

Groundwater–surface water interactions in an ephemeral savanna catchment, Kruger National Park

Groundwater–surface water interactions in an ephemeral savanna catchment, Kruger National Park

Drought and fire determine juvenile and adult woody diversity and dominance in a semi‐arid African savanna

Biotic and abiotic connections on a granitic catena: Framework for multidisciplinary research

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