Mammal burrowing in discrete landscape patches further increases soil and vegetation heterogeneity in an arid environment

Louw, M.A.; Roux, Peter C. le; Meyer-Milne, Elizabeth; Haussmann, Natalie S.

doi:10.1016/j.jaridenv.2017.02.007

Cited by 23 publications

(16 citation statements)

References 41 publications

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“…Data from the arid scrubland and mesic grassland have previously been reported in a different context (see ref. 53,54 ). Aardvark occur at all three sites and are the dominant medium-sized (i.e.…”

Section: Methodsmentioning

confidence: 99%

Testing for consistency in the impacts of a burrowing ecosystem engineer on soil and vegetation characteristics across biomes

Louw

Haussmann

Roux

2019

Sci Rep

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The impacts of ecosystem engineers may be expected to vary along environmental gradients. Due to some resources being more limited in arid than in mesic environments, disturbances created by burrowing mammals are expected to have a greater ameliorating effect in arid environments, with larger differences in microhabitat conditions expected between burrows and undisturbed areas. The aim of this study was to test if the impacts of a medium-sized burrowing mammal, the aardvark, on soil properties (soil temperature, moisture and compaction) and vegetation characteristics (plant cover, species richness and species composition) are consistent across three biomes that differ strongly in annual rainfall. Burrowing affected soil and vegetation attributes, but the direction and magnitude of these biogeomorphological impacts were not consistent across the different biomes. For example, plant species composition was altered by burrowing in the arid scrubland and in the mesic grassland, but not in the semi-arid savannah. Contrary to expectations, the difference in the impacts of burrowing between biomes were not related to rainfall, with burrowing having strong, albeit different, impacts in both the arid scrubland and the mesic grassland, but weaker effects in the semi-arid savannah. It appears, therefore, that the impacts of these biogeomorphic agents may be site-specific and that it may be difficult to predict variation in their biotic and abiotic effects across environmental gradients. As a result, forecasting the impacts of ecosystem engineers under different conditions remains a challenge to management, restoration and conservation strategies related to these types of species.

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Section: Methodsmentioning

confidence: 99%

Testing for consistency in the impacts of a burrowing ecosystem engineer on soil and vegetation characteristics across biomes

Louw

Haussmann

Roux

2019

Sci Rep

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“…Burrowing mammals capable of displacing soil also occupy heuweltjies, ranging from small rodents to considerably larger aardvarks, and evidence of mammalian bioturbation on heuweltjies is ubiquitous [5,10,48]. Although mammals can move a considerable amount of soil materials, this kind of displacement cannot be responsible for the substantial differences in the geochemical fingerprints of heuweltjie soils versus those of the surrounding, off-mound area and underlying bedrock, which had to have originated through the accretion of allochthonous aeolian sediments as discussed previously (Table 1).…”

Section: Comparison Of Heuweltjies With Other Moundsmentioning

confidence: 99%

Role of Aeolian Dust in Shaping Landscapes and Soils of Arid and Semi-Arid South Africa

2018

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The deposition of fine aeolian sediment profoundly influences the morphology of several different landscapes of the arid and semi-arid western portion of South Africa. Such landscapes and features include: (1) regularly-spaced mounds known as heuweltjies of the succulent Karoo region, (2) barren stone pavements in the more arid regions, and (3) hillslopes with smooth, curvilinear slope profiles that are mantled with coarse, stony colluvium. Investigations of each of these are presented, together with comparisons of similar features found within arid and semi-arid portions of Western North America. Recent findings suggest that the formation of the distinct, regularly-spaced heuweltjies involves a linked set of biological and physical processes. These include nutrient accumulation by termites and the production of dense vegetation patches, which, in turn, serve as a trap for aeolian sediments. Dust deposition is also responsible for the formation of stone pavements as demonstrated by research conducted principally in the Mojave Desert region of the United States. Mineralogical and geochronological studies have demonstrated that the stone clasts remain on the surface as fine aeolian sediments are translocated downward beneath the clasts resulting in a silt-rich soil horizon directly beneath the clasts. Pavements examined in South Africa have the same morphological features that can only be explained by the same process. The formation of soils on hillslopes mantled with stony colluvium are commonly viewed as having formed through the in-situ weathering of the stony colluvium. However, like pavements, mantles of coarse, stony colluvium are effective dust traps that provide the long-term stability required for advanced development of thick, fine-grained soils. This process contributes to the evolution of smooth, vegetated, curvilinear slope profiles. In each of these examples, the accumulation of dust has a profound influence, not only in soil formation, but also on the development of dominant landform characteristics. A greater awareness of these processes will contribute considerably to the growth of knowledge about soils and landscape development in the drylands of South Africa.

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“…It is understood that changes in the distribution of vegetation will change the distribution of animals that depend on it for their survival (Kosanic et al 2018). Small mammals, especially fossorial individuals, can be important ecosystem engineers in arid landscapes (Whitford & Kay 1999;Louw et al 2017). Their activities provide various functional roles in ecosystems such as nutrient cycling, soil stability, water infiltration, interactions with plants and modification of environments (Happold 2001).…”

Section: Introductionmentioning

confidence: 99%

Implications of potential biome boundary shifts for small mammal assemblages in the arid zone of South Africa

et al. 2020

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Desertification deteriorates the landscape functionality of rangelands, affecting the resilience of biome boundaries and this has a cascading effect on vegetation and animal communities. This study aimed to assess landscape functionality along the biome boundary of two arid biomes and its relationship to small mammal assemblages. The study further aimed to provide a landscape perspective of the current desertification process and projected expansion of the Desert biome in South Africa. Three Desert biome, ecotone and Succulent Karoo biome sites were selected to assess landscape functionality and small mammal assemblages over a oneyear period. The difference in landscape functionality between the three areas was assessed to determine the resilience of the biome boundary to desertification. Our results showed that the vegetation of the ecotone had higher desert-like affinities while the soils seemed resilient and remained closely related to the Succulent Karoo biome. High livestock grazing pressure, as evident in the pastoral rangeland, may further deteriorate vegetation parameters and expose the soil to erosion, thereby advancing desertification. During both winter and summer, small mammal surveys using live Sherman traps were conducted and over the total 3204 trapping nights, 119 small mammal captures were recorded from three species. Desmodillus auricularis, Elephantulus rupestris and Gerbillurus paeba all had significantly higher densities in the Succulent Karoo biome. Our study supports the view that G. paeba would be the only species able to thrive in the less diverse Desert biome. This might have implications for the ecosystem services provided by the other two small mammal species in the landscape. As the trajectory for projected desertification appears to be on track, concerted efforts in improving rangeland management are required to maintain landscape functionality and stabilise small mammal assemblages.

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Mammal burrowing in discrete landscape patches further increases soil and vegetation heterogeneity in an arid environment

Cited by 23 publications

References 41 publications

Testing for consistency in the impacts of a burrowing ecosystem engineer on soil and vegetation characteristics across biomes

Testing for consistency in the impacts of a burrowing ecosystem engineer on soil and vegetation characteristics across biomes

Role of Aeolian Dust in Shaping Landscapes and Soils of Arid and Semi-Arid South Africa

Implications of potential biome boundary shifts for small mammal assemblages in the arid zone of South Africa

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