Enrichment effects of vegetation patches on soil water content depend on precipitation and vegetation conditions: A global meta-analysis

Journal of Hydrology, Journal Year: 2025, Volume and Issue: unknown, P. 133590 - 133590

Published: May 1, 2025

Language: Английский

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Travelling pulses on three spatial scales in a Klausmeier-type vegetation-autotoxicity model

Nonlinearity, Journal Year: 2024, Volume and Issue: 37(9), P. 095008 - 095008

Published: July 18, 2024

Abstract Reaction-diffusion models describing interactions between vegetation and water reveal the emergence of several types patterns travelling wave solutions corresponding to structures observed in real-life. Increasing their accuracy by also considering ecological factor known as autotoxicity has lead more involved supporting existence complex dynamic patterns. In this work, we include an additional carrying capacity for biomass a Klausmeier-type vegetation-water-autotoxicity model, which induces presence two asymptotically small parameters: ɛ , representing usual scale separation vegetation-water models, δ directly linked autotoxicity. We construct three separate homoclinic pulse based on different scaling regimes involving with without so-called superslow plateau . The relative ordering parameters significantly influences phase space geometry underlying construction solutions. complement analysis numerical continuation constructed solutions, demonstrate (and stability) direct simulation full partial differential equation model.

Language: Английский

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Desiccation of undamaged grasses in the topsoil causes Namibia’s fairy circles – Response to Jürgens & Gröngröft (2023)

Perspectives in Plant Ecology Evolution and Systematics, Journal Year: 2024, Volume and Issue: 63, P. 125780 - 125780

Published: Feb. 27, 2024

In a novel study, Getzin et al. (2022) have excavated 500 grasses at four regions of the Namib to systematically investigate temporal process how young die in fairy circles. Based on measurements root lengths, statistical testing, and comparative photo documentations authors showed that sand termite herbivory did not cause death freshly germinated within circles (FCs). Roots those dead were initially undamaged even longer than living outside vegetation matrix, which is contrary herbivory. The dying annual FCs had significantly higher root-to-shoot ratios vital both can be attributed same grass-triggering rain event. This indicates they died from water stress because desiccating invested biomass resources into roots, trying reach deeper soil layers with more moisture, but failed. Jürgens & Gröngröft (2023) commented our research findings. Here, we shed light their statements by investigating existing data evidence circles, includes thorough literature review about proposed termite-feeding mechanism, as well describing properties around FCs. Our shows there no single study date has demonstrated systematic field form several green germinating would killed termites. We emphasize top 10 cm very susceptible drying out. this topsoil layer, long roots quickly after rainfall due lack water, these small plants cannot utilize moisture content, only found below dry topsoil. 400 during rainy season 2024, show drier matrix outside. Finally, physical conditions allow high hydraulic conductivity supports "uptake-diffusion feedback" first weeks rainfall. During two 20 depth ranged for events between 9 18% FCs, hence way above 6-8% threshold strongly declines. Even days rainfall, was still 8%. biologically active period, new germinate five days, large perennial along FC edge resprout draw established system 30 depth, desiccate days. With continuous measurements, argue greening competitively superior edge, grasses, may rapid depletion out leads

Language: Английский

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Microbial Factors May Contribute to the Persistence of Australian Fairy Circles

Journal of Biomedical Research & Environmental Sciences, Journal Year: 2024, Volume and Issue: 5(1), P. 033 - 043

Published: Jan. 1, 2024

Fairy Circles (FCs) are roughly circular, spatially periodic barren patches occurring both along the southwestern African coast, spanning Namib Desert (NFCs), and in Pilbara region of Western Australia (AFCs). The origin NFC AFC patterns is still debatable a subject ongoing research. Recently, it was argued that pathogenic soil microbes may contribute to ring formation Triodia basedowii grass which same species forms AFCs. We have analyzed, under controlled laboratory conditions, samples taken from different parts AFCs (center, periphery m3atrix) for microbiological activities by Lettuce germination experiments manipulations. In seven circles, out an average 13, root lengths germinated seeds were strongly inhibited center, lesser extent, matrix. Quantitative analyses microbial community FC center found no support hypothesis phytotoxic effect caused crust cyanobacteria due their low abundance. However, FCs identified heterotrophic bacteria fungi effect. Although our study not done with supports idea persistence inhibiting plant development bare gaps addition physical crusts resulting weathering. This suggests negative plant-soil feedback can act concert main driver mechanism AFCs, scale-dependent plant-water feedback.

Language: Английский

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Ring formation in Stipagrostis obtusa in the arid north-eastern Negev, Israel

Flora, Journal Year: 2023, Volume and Issue: 306, P. 152353 - 152353

Published: July 30, 2023

Language: Английский

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