Geology topics

Matthew D. Petrie

Publications and source records attributed to Matthew D. Petrie.

6 recordsLinked to original sources

USGS2026

Ecovoltaic solar energy development creates novel microclimate, temperature, and soil moisture patterns under solar panels in a warm desert

Background: As solar energy development expands in desert regions, new installation practices and solar technologies seek to balance ecosystem conservation and energy generation (ecovoltaics). The Gemini Solar Project, a large ecovoltaic facility located in the northeastern Mojave Desert, employed low impact installation methods to reduce disturbance of the desert ecosystem within arrays of bifacial panels mounted on solar tracking systems. We evaluated microclimate and environmental conditions across five locations: four within-facility microsites (underneath solar panels, east and west panel driplines, and interspaces between panel rows) and one in the undisturbed desert outside the facility. Results: Under panel microsites experienced lower solar radiation and evaporative demand than panel driplines, and driplines experienced lower solar radiation and evaporative demand than interspaces and undisturbed desert outside the facility. Air temperature was similar among microsites, whereas soil surface temperature was highest in interspaces and lower in under-panel and dripline microsites due to diurnal panel shading. Soil temperature was higher under panels compared to interspaces from March to September and lower in other months, and higher during daytime and lower at nighttime periods. Panel tracking and the more frequent occurrence of afternoon precipitation promoted higher soil moisture in west driplines. Water redistribution was also influenced by soil hydraulic conductivity—deep soils experienced greater west dripline soil moisture, whereas shallow soils experienced surface water pooling and greater soil moisture in the west dripline and under solar panels. Conclusions: Gemini’s ecovoltaic design promotes microclimate heterogeneity, moderating some environmental conditions while intensifying others, and often differing from fixed panel facilities with higher disturbance. This research provides critical information to balance renewable energy expansion and ecological function in warm deserts.

Nevada↗

USGS2025

Ecovoltaic solar energy development effects to microclimate, temperature, and soil moisture in panel array interspaces in a warm desert

Solar energy development is increasing in warm deserts of the southwestern United States, and ecovoltaics has emerged as an approach to maintain ecosystem function within solar facilities while meeting increasing regional energy demands. The Solar Gemini Project, located in the northeastern Mojave Desert, USA, is one of largest photovoltaic facilities incorporating an ecovoltaics approach, including novel installation practices to reduce disturbance to soil and vegetation and solar tracking bifacial photovoltaic panels to maximize energy generation. To further understand the influence of the facility on environmental conditions, we compared microclimate, temperature, and soil moisture in bare soil interspaces between panel arrays inside the facility to undisturbed desert in nearby areas outside the facility from June 2023–February 2025. Our comparisons included different seasons (summer versus winter), soil depth (shallow versus deep), and facility operation (inactive versus active panels with solar-tracking). We found lower solar radiation, wind speed, and evaporative demand inside the facility compared to outside the facility, with greater differences when panels were actively tracking. When panels were active, air temperature inside and outside the facility was similar on average, but was higher inside the facility during the day and lower at night. Soil surface temperature was lower inside the facility due to panel shading in the morning and evening, whereas soil temperature (0–15 cm) was consistently higher inside the facility. Soil moisture was higher inside the facility and did not drop to the low levels observed outside the facility. In total, we found lower evaporative demand, less heat loading, and higher soil moisture inside the Gemini facility, potentially benefitting flora and fauna in the harsh desert landscape. Yet, we also found daytime increases in air and soil surface temperature inside the facility, and persistent increases to soil temperature. These findings highlight the potentially positive and negative environmental changes associated with ecovoltaics solar energy development in warm deserts and provide evidence that can inform the optimization of solar photovoltaics design and management.

Nevada↗

USGS2025

Soil moisture partitioning between under canopy and interspace environments in shrublands of the northern Chihuahuan Desert

Soil moisture is a key link between hydrologic and ecologic processes in desert shrublands. Understanding how soil moisture is spatially distributed in desert shrublands provides valuable insights into how shrubs use and impact limiting water resources, and how shrublands may respond to future meteorological and climate change. Our goals were to determine how soil moisture is partitioned between soil volumes under canopies and in the bare soil interspaces across multiple desert shrublands, and to evaluate the roles of physical soil properties, shrub-type characteristics, meteorology, and measurement resolution in influencing and observing variation in soil moisture partitioning. Utilizing two long-term soil moisture datasets (monthly resolution, 30 years, whole soil profile measurements; and 30 min resolution, 10 years, 10–30 cm measurements), we compared soil moisture partitioning across nine northern Chihuahuan Desert shrubland sites (three sites dominated by creosotebush [ Larrea tridentata ], three by honey mesquite [ Prosopis glandulosa ], and three by tarbush [ Flourensia cernua ]) in the Jornada Basin, southern New Mexico, USA. Over 30 years, monthly, whole profile data showed that soil moisture in mesquite shrublands was consistently higher in bare soil interspaces compared to under canopies, whereas soil moisture under and between shrubs was more similar in creosotebush and tarbush shrublands. Physical soil properties were linked as explanatory variables of long-term soil moisture partitioning (monthly whole profile dataset), whereas 30-minute data showed that shorter-term periods of higher precipitation promoted greater near surface soil moisture (10–30 cm) in bare soil interspaces that was not captured at monthly time steps. Thus, although the long-term average partitioning of soil moisture in these shrublands is strongly controlled by soil physical properties, soil moisture partitioning varies at shorter timescales (daily to weekly) in response to precipitation events. Moreover, shrub-type characteristics influenced soil moisture partitioning, with dense and tall mesquite shrubs having lower under canopy soil moisture than tarbush, and root architecture potentially influencing partitioning across creosotebush sites. These results illustrate diversity in soil moisture partitioning both between and within shrublands of the northern Chihuahuan Desert, and elucidate how physical soil properties, shrub-type characteristics, and meteorological variation interact to shape their soil moisture dynamics.

New Mexico↗

USGS2025

Management and natural regeneration in multiple ponderosa pine forests of the southwestern United States

Management treatments in ponderosa pine forests of the southwestern United States (SWUS) are largely done for wildfire mitigation and restoration to lower tree densities. However, lack of natural ponderosa pine regeneration in undisturbed forests (i.e., no occurrence of stand-replacing events) may require management treatments to promote regeneration. We conducted a field and modeling study in 77 ponderosa pine forests across 7 SWUS locations, with the goal of evaluating management impacts on recent natural regeneration ( ∼ "> ∼ 20 y). We categorized management into 3 broad categories: unmanaged, thinned from above and/or below (thinning), and thinned + "> + understory burned (burning). Although climate suitability declined from 1981-2020, management treatments – especially burning – promoted natural regeneration. High density regeneration, an undesirable outcome, occurred in 21 % "> % of managed sites. In addition to effects on near-surface temperature and soil moisture, management conducive to natural regeneration was associated with the density of competing tree species, understory litter and debris cover, and adult tree cone production. Natural regeneration occurred ∼ "> ∼ 5-10 y following management, underscoring sustained effects of management treatments on tree reproduction success. Our results show that forest management treatments have the potential to promote natural ponderosa pine regeneration in the SWUS, sometimes at undesirable high densities. Study Implications: Natural ponderosa pine regeneration is declining in forests of the southwestern United States (SWUS), and may increasingly be incorporated as a goal of forest management treatments. Across a diverse set of managed and unmanaged SWUS forest sites, we found that contemporary management treatments – especially thinning + "> + prescribed understory burning – supported natural ponderosa pine regeneration over the past two decades, which were climatically unfavorable in much of the region. Our results show that existing forest management treatments have the potential to promote natural ponderosa pine regeneration in the SWUS, but will require assessment and modification through time to remain effective.

Forest Science↗

USGS2023

Widespread regeneration failure in ponderosa pine forests of the southwestern United States

As climate changes in coming decades, ponderosa pine forest persistence may be increasingly dictated by their regeneration. Sustained regeneration failure has been predicted for forests of the southwestern US (SWUS) even in absence of stand-replacing wildfire, but regeneration in undisturbed and lightly disturbed forests has been studied infrequently and at a limited number of locations. We characterized 77 ponderosa pine sites in 7 SWUS locations, documented regeneration occurring over the past ∼ "> ∼ 20 years, and utilized gridded meteorological estimates and water balance modeling to determine the climate and environmental conditions associated with regeneration failure (R0). Of these sites, 29 % "> % were R0, illuminating that regeneration failure in these forests is widespread. R0 sites were distinguished by high above- and belowground heat loading, loss of cool-season climate, and high soil moisture variation. Explanatory variables had high accuracy in identifying R0 sites, and illustrate the climate-driven pathway by which regeneration failure has occurred in the SWUS. Regeneration failure has high potential to increase in a warmer, more hydrologically variable climate, and expand regionally from lower to higher latitudes. Yet, we also found that human management interventions were associated with environmental conditions that avoided regeneration failure. To counteract regeneration-associated forest declines, interventions will need to influence climate-driven environmental change by adjusting forest characteristics at local scales. Regeneration failures are a major threat to ponderosa pine forest persistence, and they have potential to intensify and expand in a changing climate.

Arizona, Colorado, Nevada, New Mexico↗

USGS2018

Soil water dynamics at 15 locations distributed across a desert landscape: insights from a 27‐yr dataset

Desert ecosystems are primarily limited by water availability. Within a climatic regime, topography, soil characteristics, and vegetation are expected to determine how the combined effects of precipitation, temperature, and evaporative demand of the atmosphere shape the spatial and temporal patterns of water within the soil profile and across a landscape. To forecast how desert landscapes may respond to future climatic conditions, it is imperative to improve our understanding of these ecohydrologic processes. Here, we report on 27 yr of monthly soil volumetric water content (VWC) measurements and associated soils data from a site in the northern Chihuahuan Desert of North America. The dataset includes VWC and soil properties measured to 3 m in depth across 15 locations that encompass a range of Chihuahuan Desert vegetation types. We use this unique dataset (1) to generate insights into general temporal and depth patterns in VWC, (2) to analyze how VWC corresponds to measures of climatic conditions, and (3) to qualitatively evaluate the relative importance of soils, topographic setting, and vegetation type in mediating temporal patterns in VWC. Analyses of this unique dataset emphasize the importance of soil and topographic setting in determining depth and temporal patterns in VWC across time. Results emphasize the episodic nature of deep wetting events in our study system—essentially limited to three large events over the 27‐yr record driven primarily by wetter than normal winters. Comparison of soil water dynamics between mesquite shrub coppice dunes and interspace soils suggests the “island of fertility” concept does not extend to soil water. Median VWC was strongly coupled to climatic conditions over surprisingly long windows at most locations (6–18 months), suggesting that soil water at depth is decoupled from short climatic pulses. However, VWC dynamics and VWC–climate relationships varied among locations, depths, and seasons, with unexpected similarities in ecohydrologic dynamics observed among very different vegetation types (e.g., an eroded creosote shrubland and a playa grassland). These results further underscore the importance of ecohydrological investigations in these ecosystems, given forecasts for a warmer and more variable climate in deserts globally.

Ecosphere↗