Intrinsic dimensionality as a metric for temporal plant diversity evaluation: Case study from the SHIFT campaign

Ecosphere, Год журнала: 2025, Номер 16(4)

Опубликована: Апрель 1, 2025

Abstract Current biodiversity metrics derived from remote sensing data are typically applied to small local areas, require significant training data, and not easily extensible globally. Here we propose the mathematical concept of intrinsic dimensionality (ID) as a method quantify terrestrial vegetation variability without need for in situ data. We apply this technique airborne imaging spectroscopy Surface Biology Geology High Frequency Time series (SHIFT) campaign, with weekly overflights February May 2022 over region California stretching Figueroa Mountain Los Padres National Forest Point Conception adjacent coastal areas. ID is considered both spatial temporal context—spatial represents spectral across geographical at single time step, location. Results show an encouraging correlation between spatially calculated species richness despite different scales two ( p = 0.01). Spatial remained largely unchanged each step course three months during spring green‐up period when characteristics responses were changing rapidly (number remains even though spectra reflect phenological change time). The constant pseudo‐invariant surfaces such parking lots, roofs, rock, but showed increased trees, shrubs, grasses. This robustness seasonal desirable any measure because it insulated changes condition that unrelated plant richness. Even consistent acquisition dates, considering full (temporal ID), find subweekly sampling may be necessary spectrally capture cycle certain types.

Язык: Английский

The Unstable Relationship Between Drought Status and Leaf Water Content Complicates the Remote Sensing of Tree Drought Stress

Global Change Biology, Год журнала: 2025, Номер 31(4)

Опубликована: Апрель 1, 2025

Remote sensing holds promise for ecosystem-level monitoring of plant drought stress but is limited by uncertain linkages between physiological and remotely sensed metrics water content. Here, we investigate the stability relationships potential (Ψ) content (measured in situ via repeat airborne VSWIR imaging) over diel, seasonal, spatial variation two xeric oak tree species. We also compare these field-based with ones established laboratory settings that might be used as calibration. Due to confounding processes related growth, both lacked consistent when measured across space or through time. Relationships growing season were stronger more closely laboratory-based drydown methods than those (i.e., wet trees dry trees). These results provide insight into utility "space time" approaches remote demonstrate important limitations power high temporal resolution detecting stress.

Язык: Английский