Spatial patch structure and adaptive strategy for desert shrub of Reaumuria soongorica in arid ecosystem of the Heihe River Basin

Abstract

In many arid ecosystems, vegetation frequently occurs in high-cover patches interspersed in a matrix of low plant cover. However, theoretical explanations for shrub patch pattern dynamics along climate gradients remain unclear on a large scale. This context aimed to assess the variance of the Reaumuria soongorica patch structure along the precipitation gradient and the factors that affect patch structure formation in the middle and lower Heihe River Basin (HRB). Field investigations on vegetation patterns and heterogeneity in soil properties were conducted during 2014 and 2015. The results showed that patch height, size and plant-to-patch distance were smaller in high precipitation habitats than in low precipitation sites. Climate, soil and vegetation explained 82.5% of the variance in patch structure. Spatially, R. soongorica shifted from a clumped to a random pattern on the landscape towards the MAP gradient, and heterogeneity in the surface soil properties (the ratio of biological soil crust (BSC) to bare gravels (BG)) determined the R. soongorica population distribution pattern in the middle and lower HRB. A conceptual model, which integrated water availability and plant facilitation and competition effects, was revealed that R. soongorica changed from a flexible water use strategy in high precipitation regions to a consistent water use strategy in low precipitation areas. Our study provides a comprehensive quantification of the variance in shrub patch structure along a precipitation gradient and may improve our understanding of vegetation pattern dynamics in the Gobi Desert under future climate change.

Reaumuria soongorica-plant model to understand drought adaptive mechanisms of xerophyte and their potentials in improving stress tolerance in plants

“…The authors used a conceptual model, which integrated water availability and plant facilitation and competition effects. They found that R. soongorica changed from a flexible water use strategy in high precipitation regions to a consistent water use strategy in low precipitation areas (Li et al, 2019). They also found that patch height, size and plant-to-patch distance were smaller in high precipitation habitats than in low precipitation sites.…”

“…They also found that patch height, size and plant-to-patch distance were smaller in high precipitation habitats than in low precipitation sites. Climate, soil and vegetation explained 82.5% variance in patch structure (Li et al, 2019).…”

Evaluating soil quality status of fluvisols at the regional scale: A multidisciplinary approach crossing multiple variables

“…As a consequence of human activities (agriculture, urbanization, grazing and mining), soil organic carbon contents in fluvial soils would decrease, generating a reduction of soil stability and size of the aggregates, affecting fertility and biodiversity (Pulido‐Fernández, Schnabel, Lavado‐Contador, Miralles Mellado, & Ortega Pérez, 2013). In the long‐term, these soils could experience a lower water holding capacity, lower permeability and higher probability of crust formation, with the resulting dramatic decrease in infiltration rates (Fick, Belnap, & Duniway, 2020; Li, Li, Huang, Wang, & Zhang, 2019; Rosentreter & Root, 2019). Due to the absence of available water in the soil profile, vegetation will not be able to re‐establish resulting in high rates of overland flow and sediment yield (Manning, Julian, & Doyle, 2020; Wang et al, 2019).…”

Methodology for optimizing quadrat size in sparse vegetation surveys: A desert case study from the Tarim Basin

“…It is generally believed that a quadrat should cover 63%–86% of the species in the survey area; for areas with fewer species, some researchers consider 20% to be a reasonable lower limit [ 17 ]. However, the application of the SAR method in desert areas has a few limitations: (1) additional fieldwork is required to collect data for drawing the SAR curve, which is problematic due to the difficulty of conducting fieldwork in such challenging locations; (2) as a rule, desert vegetation is distributed in patches and has high spatial heterogeneity [ 5 ], which increases the variation in the samples and results in reduced robustness of the sampling surveys [ 8 , 18 ]; (3) the occurrence of extrema may present a problem. Overall, deserts have fewer plant species than other habitats and their clustering can skew the calculation and result in a quadrat size that is too large or too small.…”