The polygenetic origin of prairie mounds in northeastern California

Johnson, Donald L.; Johnson, Diana N.

doi:10.1130/2012.2490(06)

Cited by 4 publications

(3 citation statements)

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“…Among the regular vegetative and microtopographic patterns whose origins remain debated or incompletely resolved are fields of earth mounds known locally as heuweltjies in South Africa (28,29,49,109,110), Mima mounds (52,72) and burrow mounds (121,130) in western North America, surales in the Orinoco Llanos (59,162), and murundus in Brazil (51,103,108,112), along with the aforementioned fairy circles (bare-soil discs surrounded by rings of perennial grasses) in southwestern Africa (26, 54, 55, 78-80, 149, 150, 156, 160) and Australia (56,57,157).…”

Section: Controversies Over Patterning Mechanismsmentioning

confidence: 99%

“…These possibilities are often presented and debated as alternatives, and because the available data do not allow conclusive direct tests, many studies attempt to proceed by elimination: Negative (often indirect or circumstantial) evidence against certain hypotheses is more central in these arguments than is positive evidence in favor of any other hypothesis (27,29,54,55,80). Although the potential for polygenesis by multiple interacting mechanisms has been acknowledged in some cases (72,104), the literature has not yet fully internalized this possibility (see also next section).…”

Section: Controversies Over Patterning Mechanismsmentioning

confidence: 99%

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Spatial Self-Organization of Ecosystems: Integrating Multiple Mechanisms of Regular-Pattern Formation

Pringle

Tarnita²

2017

Annu. Rev. Entomol.

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Large-scale regular vegetation patterns are common in nature, but their causes are disputed. Whereas recent theory focuses on scale-dependent feedbacks as a potentially universal mechanism, earlier studies suggest that many regular spatial patterns result from territorial interference competition between colonies of social-insect ecosystem engineers, leading to hexagonally overdispersed nest sites and associated vegetation. Evidence for this latter mechanism is scattered throughout decades of disparate literature and lacks a unified conceptual framework, fueling skepticism about its generality in debates over the origins of patterned landscapes. We review these mechanisms and debates, finding evidence that spotted and gapped vegetation patterns generated by ants, termites, and other subterranean animals are globally widespread, locally important for ecosystem functioning, and consistent with models of intraspecific territoriality. Because these and other mechanisms of regular-pattern formation are not mutually exclusive and can coexist and interact at different scales, the prevailing theoretical outlook on spatial self-organization in ecology must expand to incorporate the dynamic interplay of multiple processes.

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Section: Controversies Over Patterning Mechanismsmentioning

confidence: 99%

Section: Controversies Over Patterning Mechanismsmentioning

confidence: 99%

Spatial Self-Organization of Ecosystems: Integrating Multiple Mechanisms of Regular-Pattern Formation

Pringle

Tarnita²

2017

Annu. Rev. Entomol.

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“…Although the heuweltjies and Mima-type mounds share some features, including evidence from a site in the south-central USA for an aeolian sediment component [42], substantial contrasts exist that suggest differing developmental pathways and origins. Johnson and Johnson [43] provide evidence for the operation of a complex set of mechanisms including bioturbation, seasonal frost heaving, erosional processes, and occasional aeolian inputs in forming mounds in cooler, high-elevation sites with thin, clay-rich soils above basalt flows. Although the Mima-type mounds at sites in North America commonly tend to be regularly spaced (e.g., Figure 2C; [44,45]), they are typically smaller in diameter and much more closely spaced than are heuweltjies ( Figure 2B,C).…”

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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Large short-range variation in soil properties in a natural grassland indicates non-tree related catena disruption

Temme¹,

Kroef

Stoof

et al. 2022

CATENA

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The polygenetic origin of prairie mounds in northeastern California

Cited by 4 publications

References 0 publications

Spatial Self-Organization of Ecosystems: Integrating Multiple Mechanisms of Regular-Pattern Formation

Spatial Self-Organization of Ecosystems: Integrating Multiple Mechanisms of Regular-Pattern Formation

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

Large short-range variation in soil properties in a natural grassland indicates non-tree related catena disruption

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