An official website of the United States government
Premise of the StudyThe C3desert shrub ocotillo (Fouquieria splendens) completely lacks xeromorphic leaves but is uncommonly both stem succulent and repetitively drought deciduous (documented to have produced many foliation–defoliation cycles during a growing season). Both adaptations conserve water in this xerophyte, but are the roles of succulence and deciduousness merely redundant? The observation that year‐to‐year reproductive effort was relatively consistent while vegetative growth was not offered a critical clue that, coupled with long‐term precipitation data, helped answer this question. MethodsAt two sites in the Chihuahuan Desert in southern New Mexico, United States, 22 ocotillos were studied annually for more than two decades to explore the relationships among reproductive effort, vegetative stem growth, and patterns of precipitation. Key ResultsVegetative stem growth occurred in mid‐ to late summer (July–September), the season of maximum precipitation in the Chihuahuan Desert, and was significantly related to summer precipitation received in the year of growth. Reproductive effort occurred in early to late spring (April–June), which with winter account for minimum precipitation during the year, but was significantly related to summer precipitation received in the previous year, suggesting the importance of stem succulence and stored water. ConclusionsWhile highly variable summer precipitation was responsible for enormous fluctuations in annual ocotillo stem growth, stem succulence insulated reproductive effort from such immense variability. Stem‐stored water allowed the production of flowers and fruits to proceed relatively consistently during the driest years and during the driest time of year in the Chihuahuan Desert.
more »
« less
Whole community shotgun metagenomes of two biological soil crust types from the Mojave Desert
ABSTRACT We present six whole community shotgun metagenomic sequencing data sets of two types of biological soil crusts sampled at the ecotone of the Mojave Desert and Colorado Desert in California. These data will help us understand the diversity and function of biocrust microbial communities, which are essential for desert ecosystems.
more »
« less
- Award ID(s):
- 1846376
- PAR ID:
- 10554477
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Editor(s):
- Stewart, Frank J
- Publisher / Repository:
- ASM Press
- Date Published:
- Journal Name:
- Microbiology Resource Announcements
- Volume:
- 13
- Issue:
- 3
- ISSN:
- 2576-098X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract QuestionsReordering of dominant species is an important mechanism of community response to global environmental change. We asked how wildfire (apulseevent) interacts with directional changes in climate (environmentalpresses) to affect plant community dynamics in a Chihuahuan Desert grassland. LocationSevilleta National Wildlife Refuge, Socorro County, New Mexico, USA. MethodsVegetation cover by species was measured twice each year from 1989 to 2019 along two permanently located 400‐m long line intercept transects, one in Chihuahuan Desert grassland, and the second in the ecotone between Chihuahuan Desert and Great Plains grasslands. Trends in community structure were plotted over time, and climate sensitivity functions were used to predict how changes in the Pacific Decadal Oscillation (PDO) affected vegetation dynamics. ResultsCommunity composition was undergoing gradual change in the absence of disturbance in the ecotone and desert grassland. These changes were related to the reordering of abundances between two foundation grasses,Bouteloua eriopodaandB. gracilis, that together account for >80% of above‐ground primary production. However, reordering varied over time in response to wildfire (apulse) and changes in the PDO (apress). Community dynamics were initially related to the warm and cool phases of the PDO, but in the ecotone these relationships changed following wildfire, which reset the system. ConclusionSpecies reordering is an important component of community dynamics in response to ecological presses. However, reordering is a complex, non‐linear process in response to ecological presses that may change over time and interact with pulse disturbances.more » « less
-
Abstract BackgroundThe increasing number of chromosome-level genome assemblies has advanced our knowledge and understanding of macroevolutionary processes. Here, we introduce the genome of the desert horned lizard, Phrynosoma platyrhinos, an iguanid lizard occupying extreme desert conditions of the American southwest. We conduct analysis of the chromosomal structure and composition of this species and compare these features across genomes of 12 other reptiles (5 species of lizards, 3 snakes, 3 turtles, and 1 bird). FindingsThe desert horned lizard genome was sequenced using Illumina paired-end reads and assembled and scaffolded using Dovetail Genomics Hi-C and Chicago long-range contact data. The resulting genome assembly has a total length of 1,901.85 Mb, scaffold N50 length of 273.213 Mb, and includes 5,294 scaffolds. The chromosome-level assembly is composed of 6 macrochromosomes and 11 microchromosomes. A total of 20,764 genes were annotated in the assembly. GC content and gene density are higher for microchromosomes than macrochromosomes, while repeat element distributions show the opposite trend. Pathway analyses provide preliminary evidence that microchromosome and macrochromosome gene content are functionally distinct. Synteny analysis indicates that large microchromosome blocks are conserved among closely related species, whereas macrochromosomes show evidence of frequent fusion and fission events among reptiles, even between closely related species. ConclusionsOur results demonstrate dynamic karyotypic evolution across Reptilia, with frequent inferred splits, fusions, and rearrangements that have resulted in shuffling of chromosomal blocks between macrochromosomes and microchromosomes. Our analyses also provide new evidence for distinct gene content and chromosomal structure between microchromosomes and macrochromosomes within reptiles.more » « less
-
Stewart, Frank J. (Ed.)ABSTRACT We describe the metagenome composition, community functional annotation, and prokaryote diversity in calcareous stromatolites from a dry stream bed of the San Felipe Creek in the Anza Borrego Desert. Analyses show a community capable of nitrogen fixation, assimilatory nitrate reduction, biofilm formation, quorum sensing, and potential thick-walled akinete formation for desiccation resistance.more » « less
-
Abstract AimTo review the histories of the Colorado River and North American monsoon system to ascertain their effects on the genetic divergence of desert‐adapted animals. LocationLower Colorado River region, including Mojave and Sonoran deserts, United States. MethodsWe synthesized recent geological literature to summarize initiation phases of lower Colorado River evolution, their discrepancies, and potential for post‐vicariance dispersal of animals across the river. We simulated data under geological models and performed a meta‐analysis of published and unpublished genetic data including population diversity metrics, relatedness and historical migration rates to assess alternative divergence hypotheses. ResultsThe two models for arrival of the Colorado River into the Gulf of California impose east‐west divergence ages of 5.3 and 4.8 Ma, respectively. We found quantifiable river‐associated differentiation in the lower Colorado River region in reptiles, arachnids and mammals relative to flying insects. However, topological statistics, historical migration rates and cross‐river extralimital populations suggest that the river should be considered a leaky barrier that filters, rather than prevents, gene flow. Most markers violated neutrality tests. Differential adaptation to monsoon‐based precipitation differences may contribute to divergence between Mojave and Sonoran populations and should be tested. Main ConclusionsRivers are dynamic features that can both limit and facilitate gene flow through time, the impacts of which are mitigated by species‐specific life history and dispersal traits. The Southwest is a geo‐climatically complex region with the potential to produce pseudocongruent patterns of genetic divergence, offering a good setting to evaluate intermediate levels of geological‐biological (geobiological) complexity.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1128/mra.00980-23
