Desert Climate Regionalization for Joshua Tree National Park and Surrounding Areas Using New Climate Network Observations

A new amalgamation of weather stations in and around Joshua Tree National Park in southeastern California, USA has allowed for objective climate analysis regionalization at a much finer scale than past studies. First, it sets a baseline for many regions within the park’s boundaries which were not subject to direct observations. Second these new observations are key to understanding shifting microclimate regimes in a desert ecosystem prone to the effects of climate change. Principal component analysis was used to regionalize the climate network based on monthly temperature and precipitation climate observations and standardized anomalies. Both the observation values and standardized climate anomalies identified regional boundaries. In general, these boundaries align with traditional ideas and past studies of the Mojave and Sonoran Deserts based on elevation (specifically the 1000m contour) for the National Park. Standardized anomaly values identified a boundary based on seasonal precipitation, while observation values identified a boundary based on elevation. The boundary line within the park is similar for both data approaches, with the boundary running along the higher western third of the park. Conversely, the two methods differ significantly in the Coachella Valley, where low elevations and low precipitation meets winter dominated seasonal precipitation. This study highlights the importance and opportunity of field observations to create climatological and ecological regionalization, as well as constructs a baseline to monitor and manage shifting desert regions in the future.

Supplemental Material: Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc

<div>Table S1: SHRIMP zircon U-Pb geochronology data for six samples from the Cadiz Valley batholith. Table S2: SHRIMP zircon U-Pb geochronology data for six samples from the Federal 2-26 Cajon Pass drill core. Table S3: Whole-rock major- and trace-element geochemistry of granitic rocks from Joshua Tree National Park and the Cadiz Valley batholith measured by X-ray fluorescence (XRF) and inductively coupled plasma–mass spectrometry (ICP-MS). Table S4: Rb/Sr and Sm/Nd isotope data from the Joshua Tree National Park and Cadiz Valley batholith. Table S5: Locations, data, and references used to generate histograms in Figure 5.<br></div>

Supplemental Material: Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc

<div>Table S1: SHRIMP zircon U-Pb geochronology data for six samples from the Cadiz Valley batholith. Table S2: SHRIMP zircon U-Pb geochronology data for six samples from the Federal 2-26 Cajon Pass drill core. Table S3: Whole-rock major- and trace-element geochemistry of granitic rocks from Joshua Tree National Park and the Cadiz Valley batholith measured by X-ray fluorescence (XRF) and inductively coupled plasma–mass spectrometry (ICP-MS). Table S4: Rb/Sr and Sm/Nd isotope data from the Joshua Tree National Park and Cadiz Valley batholith. Table S5: Locations, data, and references used to generate histograms in Figure 5.<br></div>

Amplicon Sequencing of Rock-Inhabiting Microbial Communities from Joshua Tree National Park, USA

Endolithic microorganisms have been reported to date in hot and cold drylands worldwide, where they represent the prevailing life forms ensuring ecosystem functionality, playing a paramount role in global biogeochemical processes. We report here an amplicon sequencing characterization of rocks collected from Joshua Tree National Park (JTNP), USA.

Hydrological Analysis for Infrastructure Planning and Development at the North Entrance Joshua Tree National Park

Rains in the Mojave Desert region are intense and result in the destruction of property. This destruction is significant and affects development plans in the area. Joshua Tree National Park (JTNP) is one of the areas affected as a result of flash floods in the Mojave Desert region. As part of the efforts to minimize the effects caused by flash floods in the park, there was a need to carry out a hydrological analysis of surface runoff in order to map out high risk areas that are susceptible to floods after Monsoonal rains, identify areas in the park that require diversion berms, and establish the effectiveness of the existing diversion berms. The analysis result was a 3D topographic model and a map that contains high flood risk areas and potential areas where diversion berms may be constructed to divert surface runoff and protect the park’s infrastructure.

Leveraging Stakeholders to Cover Budgetary Shortfalls in U.S. National Parks: Lessons from the 2018/2019 Government Shutdown and Joshua Tree National Park

Joshua Tree National Park is a remarkable desert ecosystem made iconic by the famed Joshua trees that dot the landscape. In 1994, a majority of Joshua Tree’s holdings were designated as “wilderness” (a legal status in the U.S.). Subsequently, Joshua Tree was buffeted by deleterious anthropogenic forces and suffered from severe budgetary constraints. In 2018/2019, a U.S. Government shutdown forced the Joshua Tree staff into furlough, while the park remained open to visitors. The response of local volunteers, who took responsibility for educating visitors about park policies and ecosystem conservation in the midst of the shutdown, shows the extent to which networks of local and community volunteers can be mobilized to mitigate at least some of the effects of budgetary constraints that affect the wilderness and national park lands.