| 1. |
- Ekblom, Anneli, et al.
(författare)
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A Historical Ecology of the Limpopo and Kruger National Parks and Lower Limpopo Valley
- 2011
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Ingår i: Journal of Archaeology and Ancient History. - Uppsala : Department of Archaeology and Ancient History. - 2001-1199. ; 1:1, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- The paper uses new palaeo-ecological data and a selective review of archaeological and written sources to show how social and natural history over the last 1200 years have interacted to form the present day landscape of Limpopo National Park and Northern Kruger National Park. The long-term mosaic of different communities in this landscape, hunter and gatherers, pastoralists, farmers and traders has, over time, contributed to shape and reshape a heterogeneous landscape. While some features in this landscape, such as water scarcity, have remained stable over time, there have also been major transformations in both the physical landscape and social life. The natural mosaics have been utilised and enhanced over time and the combination of natural and cultural mosaics are reflected in the landscape through archaeological sites, the pollen record and in the present day landscape.
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| 2. |
- Ekblom, Anneli, 1969-, et al.
(författare)
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Conservation through Biocultural Heritage-Examples from Sub-Saharan Africa
- 2019
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Ingår i: Land. - : MDPI. - 2073-445X. ; 8:1
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Forskningsöversikt (refereegranskat)abstract
- In this paper, we review the potential of biocultural heritage in biodiversity protection and agricultural innovation in sub-Saharan Africa. We begin by defining the concept of biocultural heritage into four interlinked elements that are revealed through integrated landscape analysis. This concerns the transdisciplinary methods whereby biocultural heritage must be explored, and here we emphasise that reconstructing landscape histories and documenting local heritage values needs to be an integral part of the process. Ecosystem memories relate to the structuring of landscape heterogeneity through such activities as agroforestry and fire management. The positive linkages between living practices, biodiversity and soil nutrients examined here are demonstrative of the concept of ecosystem memories. Landscape memories refer to built or enhanced landscapes linked to specific land-use systems and property rights. Place memories signify practices of protection or use related to a specific place. Customary protection of burial sites and/or abandoned settlements, for example, is a common occurrence across Africa with beneficial outcomes for biodiversity and forest protection. Finally, we discuss stewardship and change. Building on local traditions, inclusivity and equity are essential to promoting the continuation and innovation of practices crucial for local sustainability and biodiversity protection, and also offer new avenues for collaboration in landscape management and conservation.
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| 3. |
- Ekblom, Anneli, 1969-, et al.
(författare)
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Dung fungi as indicators of past herbivore abundance, Kruger and Limpopo National Park
- 2010
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 296:1-2, s. 14-27
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Tidskriftsartikel (refereegranskat)abstract
- Effective wildlife management needs historical data on herbivore abundance and its interactions with vegetation, climate and disturbance over longer time periods than is available through observational and archive data. Spores specific to herbivore dung provide a potential source of information on past herbivore abundances. This paper sets out to evaluate the potential of fungal spores as environmental indicators and in particular the use of coprophilous fungi in understanding past herbivore densities and their impact on the savanna landscape of Kruger and Limpopo National Parks (South Africa and Mozambique). Spore assemblages from six sedimentary cores are analysed and compared with the pollen data. Spores of coprophilous fungi, Coniochaeta cf ligniaria, and Sordariaceae in particular provide a valuable source of information about past herbivore densities. The spore assemblages of investigated localities show historical fluctuations in herbivore abundance. Peaks in wild/domestic herbivore densities can be seen, on a local scale from 800– 900 AD and another at 1400 AD, however, these cannot be linked with any significant changes in vegetation. The last 200-300 years have seen an increased abundance of herbivores in the Limpopo floodplain sites, particularly domestic cattle. There is no clear correspondence between changes in herbivore abundance and local vegetation in this period or the 20th century. However, domestic cattle, together with wild herbivores, probably contributed to creating a mosaic type of landscape with heterogeneous tree cover.
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| 4. |
- Ekblom, Anneli, 1969-, et al.
(författare)
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Fire history and fire ecology of Northern Kruger (KNP) and Limpopo National Park (PNL), southern Africa
- 2010
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 20:7, s. 1063-1077
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Tidskriftsartikel (refereegranskat)abstract
- This paper explores the general correlations between fire and grass/tree relationships, as represented by fossil charcoal and pollen, from different vegetation types in the savanna ecosystems of the neighbouring Kruger (KNP) and Limpopo (PNL) national parks. Our analysis suggests that the basic presumption that fire is a main driver of vegetation dynamics in the savanna ecosystem by suppressing tree seedlings and encouraging grasses needs to be re-examined. An improved approach is to understand how fire may act both as a negative and positive feedback in different vegetational phases and both as a driver and responder in transitions between phases. The correlation between arboreal pollen (AP) percentages and charcoal influx suggests that in the grassland phase (< 5% AP), fire acts as a driver of woody recruitment and as a positive feedback, i.e. potentially driving the system to shift into a savanna phase. In the savanna phase (5–10% AP) fire limits woody recruitment and acts as a negative feedback in maintaining the savanna. Thus, in the savanna phase other factors than fire alone drive the transition from savanna to woodland-forest. In the riparian phase, where evidence of farming is present particularly from ad 1600 onwards, fire appears to facilitate tree recruitment where AP ranges between c. 10 and 20% AP. Though a decline in AP abundance can be seen contemporaneously with charcoal peaks, our analysis suggests that overall, human-induced fires do not seem to have a negative impact on woody cover. Our results have implications for fire management as riparian-dominated phases and savannas with a sufficient woody cover are less sensitive to changes in fire policies than open grasslands that may, with a change in fire frequency, change into another state.
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| 5. |
- Ekblom, Anneli, 1969-, et al.
(författare)
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Hierarchy and scale : testing the long term role of water, grazing and nitrogen in the savanna landscape of Limpopo National Park (Mozambique)
- 2010
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Ingår i: Landscape Ecology. - : Springer Science and Business Media LLC. - 0921-2973 .- 1572-9761. ; 25:10, s. 1529-1546
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Tidskriftsartikel (refereegranskat)abstract
- This paper compares vegetation dynamics at two sites in the savanna landscape of Limpopo National Park (PNL), Mozambique. In order to test the relationship between vegetation cover and hydrology, nutrient availability and disturbance from grazing and fire over the last 1,200 years at local (100 m2) scales, we use palaeoecological data (i.e. pollen assemblages, charcoal abundance, C/N ratio, stable isotopes and herbivore-associated spore abundance). Two pans governed by similar rainfall regimes (on average 600 mm/year) but different hydrologies are compared. Chixuludzi Pan is responsive to the Limpopo River and is more water rich than Radio Pan, which is situated in a dry landscape with little surface water. The analysis suggests that in savannas where water is scarce, the recruitment of woody taxa is constrained mainly by the availability of underground water. In the Radio Pan sequence, the present grassland savanna has been stable throughout the time studied. In contrast, the Chixuludzi Pan savanna landscape where local hydrology, due to the proximity of Limpopo River, allows for a higher water availability the relationship between grass-arboreal pollen suggests a greater variability in vegetation cover, and other factors such as grazing, herbivory and nitrogen availability are important as controlling mechanisms for woody cover. The historical depth of the analysis enables a sub-hierarchy of local scale process to be identified, in this case local hydrology. Local water availability is shown to override the effect of regional rainfall and, in turn, to control the influence of other local scale factors such as nutrients and grazing.
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| 6. |
- Ekblom, Anneli, 1969-, et al.
(författare)
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Rainfall variability and vegetation dynamics of the lower Limpopo Valley, Southern Africa, 500 AD to present
- 2012
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 363, s. 69-78
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Tidskriftsartikel (refereegranskat)abstract
- The long-term responses of vegetation to climate variability are of relevance for predicting present and future vegetation change, and have implications for the management of savanna and riparian ecosystems. This paper explores the links between regional rainfall, hydrology and vegetation dynamics in the savannas and riverine forests of the lower Limpopo Valley, southern Africa, from 800 AD to the present, reviewing palaeoecological data (fossil pollen, spores, diatoms and lithology) from several hydrological systems in Kruger National Park (KNP), South Africa and Limpopo National Park (PNL), Mozambique. The PNL-KNP records show that riverine arboreal taxa expanded during wetter periods, including 800-1400 AD and after 1800 AD. Between 1400 and 1800 AD, grasses, savanna taxa and generalist taxa were favored over riparian taxa, a change that is linked with the onset of dry spells in the region (corresponding to the so-called Little Ice Age). The most extreme drought events around 1700 AD resulted in a marked decline of riparian forest taxa near Lake Mapimbi, KNP. In contrast, many water-scarce sequences away from the riverine environment, such as Radio Pan, Mafayeni Pan, Malahlapanga Pan and Lake Makwadzi show stable grassland vegetation throughout the last 1200 years. The results demonstrate the resilience of the grassland-savanna ecosystems to projected climate change with warmer and overall drier climate. The riverine forests are predicted to be more vulnerable especially as more extreme weather events are projected.
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| 7. |
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| 8. |
- Ekblom, Anneli, 1969-, et al.
(författare)
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Water flow, ecological dynamics, and management in the lower Limpopo Valley : a long‐term vie
- 2017
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Ingår i: WIREs Water. - : Wiley. - 2049-1948. ; 4:5
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Tidskriftsartikel (refereegranskat)abstract
- In this contribution, we review long-term (millennial-decadal scale) river-flow changes, climate interactions, and interlinkage with vegetation dynamics, as well as society and policy, focusing on the lower Limpopo Valley (from the South African border through Mozambique). Drawing on paleoecological data, we address the valley's potential for defining critical ecological thresholds and managing an adaptive ecological landscape, by focusing on the dynamic relationship between different drivers (fire, hydrology, and grass/tree relationships). We briefly review the long-term interactions between water flow, climate variability, and society using archeological records and written sources. Lastly, we analyze the social and political context of water management, focusing on the last 100 years and transboundary water management. We also discuss planning and mitigation in relation to climate change and rainfall extremes that are projected to increase. It is stressed that forward-thinking policies must heed long-term climate variability, hydrology and biological and social impact and to plan and mitigate for environmental events. The discussion also brings to the fore the importance of an adaptable and equitable strategy in cross-border water sharing.
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| 9. |
- Elinor, Breman, et al.
(författare)
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Phytolith-based environmental reconstruction from an altitudinal gradient in Mpumalanga, South Africa, 10,600 BP-present
- 2019
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Ingår i: Review of Palaeobotany and Palynology. - : Elsevier BV. - 0034-6667 .- 1879-0615. ; 263, s. 104-116
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Tidskriftsartikel (refereegranskat)abstract
- Studying vegetation change across biome boundaries provides insight into vegetation resilience. In this study, shifts in grassland composition are reconstructed from sediments in three wetland sites across altitudinal gradient from 2128 to 897 m.a.s.l., representing a gradient from the grassland biome to the grassland/savanna boundary in the Mpumalanga region, north-eastern South Africa. Phytolith records from Verloren Valei (dated from 10,600 BP), Graskop (dated from 6500 BP) and Versailles (dated from 4500 BP) are used to reconstruct shifts in grassland composition and vegetation change. Phytolith morphotypes are used to construct environmental indices that are correlated with pollen main ecological groups, charcoal and delta 13C and C/N ratio. The results are compared to available regional paleoclimate data. Both Verloren Valei and Graskop have been dominated by grassland, but Versailles show a stronger influence of bushveld/savanna pollen. Phytolith data suggest that grassland composition was stable at Versailles and Graskop, but grassland at Verloren Valei has changed significantly over time. The early Holocene was dominated by a Pooideae/Chloridoideae C3 and C4 grassland, probably a remnant of the earlier Pleistocene cool-dry conditions. After 8500 BP grassland composition changed gradually to a Chloridoideae and Panicoidea dominated C4 grassland BP, and finally a moist Cyperaceae and Panicoidea dominated C3/C4 grassland after 4000 BP. This shift possibly occurs as a delayed response to the warmer and wetter conditions of the mid Holocene optimum at this high altitude site. The results suggest that the grassland/savanna boundary has remained stable over time, indicating considerable resilience of grasslands to climate change. This resilience may be related to the turnover of species within the grassland biome, as indicated by shifts between 8500 and 4000 BP at Verloren Valei.
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| 10. |
- Gillson, Lindsey, et al.
(författare)
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Holocene palaeo-invasions : the link between pattern,process and scale in invasion ecology?
- 2008
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Ingår i: Landscape Ecology. - : Springer Science and Business Media LLC. - 0921-2973 .- 1572-9761. ; 23:7, s. 757-769
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Tidskriftsartikel (refereegranskat)abstract
- Invasion ecology has made rapid progress in recent years through synergies with landscape ecology, niche theory, evolutionary ecology and the ecology of climate change. The palaeo-record of Holocene invasions provides a rich but presently underexploited resource in exploring the pattern and process of invasions through time. In this paper, examples from the palaeo-literature are used to illustrate the spread of species through time and space, also revealing how interactions between invader and invaded communities change over the course of an invasion. The main issues addressed are adaptation and plant migration, ecological and evolutionary interactions through time, disturbance history and the landscape ecology of invasive spread. We consider invasions as a continuous variable, which may be influenced by different environmental or ecological variables at different stages of the invasion process, and we use palaeoecological examples to describe how ecological interactions change over the course of an invasion. Finally, the use of palaeoecological information to inform the management of invasions for biodiversity conservation is discussed.
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