Examining multi-scale dynamics of drylands amid multi-year wet and dry periods using imagery

Authors: HEINTZMAN, LUCAS - Oak Ridge Institute For Science And Education (ORISE); Peters, Debra; Savoy, Heather; RAMIREZ, GEOVANY - New Mexico State University

Submitted to: US-International Association for Landscape Ecology
Publication Type: Abstract Only
Publication Acceptance Date: 2/23/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Our objective was to examine changes in patch- and landscape-scale vegetation dynamics for ecosystems representing the Chihuahuan Desert (upland grasslands, creosotebush shrublands, mesquite shrublands, and tarbush shrublands) during multi-year wet and dry periods. Twelve locations were selected that were distributed across the Jornada Long Term Research site in southern New Mexico, USA. Since 1989, these locations have been field-surveyed annually (via 49 1m2 quadrats per site) and used for validation of the imagery. We assessed landscape patterns derived from aerial imagery in 2005, 2009, 2011, 2014, 2016, and 2018; using unsupervised classification. These years were chosen as they encompassed periods of regional shifts in hydrological regime (wet year: 2005; dry years: 2009, 2011; average years: 2014, 2016; 2018) and featured data availability that captured our study extent. At the patch scale: our results indicated levels of vegetative dynamism, however these changes were often subtle, and frequently did not correspond to field-based estimates (due to multiple species assemblages inducing spectral mixing, and soil background masking effects). Yet, our patch-based observations emphasize the influence of wet-dry periods on dryland ecosystem structural properties and their potential corresponding vegetative lag effects across scales.