Jornada Basin LTER (JRN) - United States of America

Figure 1. Microscale self-segregation of cyanobacterial species in biocrusts. A Patches attributable to M. vaginatus (dashed white lines) and Parifilum sp. (dashed black lines) on a rehydrated biocrust are visible through differential coloration. Areas sampled for bulk soil (B) and cyanobacterial bundles (A1-4) are indicated by circles. Scale bar is 1 cm. (Nelson et al., 2022)

Figure 2. Impact of connectivity modifiers (conmods) on herbaceous cover in the TRIGGER experiment. (A) cover measurements in treated and control during 3 years since initiation.

Figure 2. Impact of connectivity modifiers (conmods) on herbaceous cover in the TRIGGER experiment. (B) conmod overhead imagery showing 2022 forb growth.

Figure 3. Effects of reducing shrub competition (“plant scale”) and aeolian connectivity (“patch scale”) on perennial grass establishment, averaged across the 15 blocks of the cross-scale interactions study (CSIS), showing modest impacts of treatments on their own, but much larger interactive effects.

Figure 4. Competition intensity (CI) for honey mesquite populations across the Jornada Basin, showing three classes of Low (0

Figure 5. Hypothetical relationship between timing of senescence for grasses (green line) and shrubs (orange line) and annual precipitation amount. Saturation of surface soils at higher rainfall amounts results in percolation to deeper soil depths accessible by shrubs, eliciting a senescence response (Currier & Sala, 2022).

Figure 6. Thiel-Sen slope of moving window covariance analysis between perennial herbaceous vegetation and bare ground ("xerification") for years 1986 through 2020 at the JRN LTER site. Yellow colors indicate little or no directional change through time, while increasingly negative Thiel-Sen slopes (darker green colors) indicate potential ("imminent") ecological state change. Red colors (positive Thiel-Sen slopes) indicate areas of earlier high covariance, where new states are dominant/stable in more recen

Figure 7. Adaptation of the Noy-Meir (1973) pulse-reserve concepts to show growth strategies of microbes and plants under pulsed rainfall regimes (Garcia-Pichel & Sala, 2022). Nimble response (NIR) organisms (e.g. microbes) respond more rapidly to pulses, including short pulses, with less reliance on (and accumulation of) carbohydrate reserves. Torpid response (TOR) organisms (e.g. plants) utilize reserves of carbohydrates in roots or seeds to initiate growth and must devote more resources in late growth to