@article {JRN54924, title = {Synchronous species responses reveal phenological guilds: implications for management}, journal = {Ecosphere}, volume = {9}, year = {2018}, month = {09/2018}, pages = {1-23}, chapter = {1}, abstract = {

Phenological studies are critical for understanding the ability of terrestrial ecosystems to respond to changes in climate. Monitoring seasonal transitions at the species or community level across large areas is challenging and expensive. One approach for lowering costs is to identify phenological guilds{\textemdash}groups of species that exhibit similar timing of seasonal transitions{\textemdash}and limit monitoring to a smaller number of species within a guild. In this study, we evaluated 23 consecutive years of monthly observations of individual species at 15 long-term study sites at the Jornada Basin USDA-Long-Term Ecological Research site to identify patterns in the onset of three phenophases{\textemdash}leaf-out, flower, and fruit{\textemdash}of 16 widely occurring species in the arid southwestern United States and to investigate the existence of phenological guilds. We conducted univariate analyses of distributions in the timing of leaf, flower, and fruit production across time and space and multivariate cluster analysis of the time series to identify coherent groups of species{\textendash}site instances that exhibit coherence in timing of phenophase onsets (i.e., guilds). The six species of C3 shrubs demonstrated greater consistency in timing of all phenophases relative to C4 grasses. Further, we found that in all species, leaf-out occurred prior to the onset of the summer monsoon rains. Cluster analysis revealed six groups of species{\textendash}site observations demonstrating high within-year concordance in timing of leaf-out and first fruit across variable site conditions and rainfall years. The six groups for timing of first fruit differed from those for first leaf in that they exhibited greater multi-species membership and within-year variability in timing. We propose that use of phenological guilds can improve the efficiency of ecosystem monitoring, predictive models of ecosystem cues driving phenological events, and land management outcomes.

}, keywords = {Chihuahuan Desert, drylands, first fruit, first leaf, long-term ecological research, pattern recognition, phenological functional group, plant phenology, Special Feature: Dynamic Deserts, start of season}, doi = {doi.org/10.1002/ecs2.2395}, url = {files/bibliography/18-017.pdf}, author = {Dawn M. Browning and Theresa Crimmins and D. K. James and S. Spiegal and Matthew Levi and John P. Anderson and Debra C. Peters} } @article {49876, title = {Hierarchial analysis of vegetation dynamics over 71 years: soil-rainfall interactions in a Chihuahuan Desert ecosystem}, journal = {Ecological Applications}, volume = {22}, year = {2012}, month = {04/2012}, pages = {909-926}, chapter = {909}, abstract = {

Proliferation of woody plants in grasslands and savannas is a persistent problem globally. This widely observed shift from grass to shrub dominance in rangelands worldwide has been heterogeneous in space and time largely due to cross-scale interactions among soils, climate, and land-use history. Our objective was to use a hierarchical framework to evaluate the relationship between spatial patterns in soil properties and long-term shrub dynamics in the northern Chihuahuan Desert of New Mexico, USA. To meet this objective, shrub patch dynamics from 1937 to 2008 were characterized at patch and landscape scales using historical imagery and a recent digital soils map. Effects of annual precipitation on patch dynamics on two soils revealed strong correlations between shrub growth on deep sandy soils and above-average rainfall years (r = 0.671, P = 0.034) and shrub colonization and below-average rainfall years on shallow sandy soils (r = 0.705, P = 0.023). Patch-level analysis of demographic patterns revealed significant differences between shrub patches on deep and shallow sandy soils during periods of above- and below-average rainfall. Both deep and shallow sandy soils exhibited low shrub cover in 1937 (1.0\% {\textpm} 2.3\% and 0.3\% {\textpm} 1.3\%, respectively [mean {\textpm} SD]) and were characterized by colonization or appearance of new patches until 1960. However, different demographic responses to the cessation of severe drought on the two soils and increased frequency of wet years after 1960 have resulted in very different endpoints. In 2008 a shrubland occupied the deep sandy soils with cover at 19.8\% {\textpm} 9.1\%, while a shrub-dominated grassland occurred on the shallow sandy soils with cover at 9.3\% {\textpm} 7.2\%. Present-day shrub vegetation constitutes a shifting mosaic marked by the coexistence of patches at different stages of development. Management implications of this long-term multi-scale assessment of vegetation dynamics support the notion that soil properties may constrain grassland remediation. Such efforts on sandy soils should be focused on sites characterized by near-surface water-holding capacity, as those lacking available water-holding capacity in the shallow root zone pose challenges to grass recovery and survival.

}, keywords = {aerial photography, Chihuahuan Desert, cross-scale linkages, ecological-state mapping, hierarchy theory, Jornada Basin LTER, New Mexico USA, object-based change detection, petrocalcic soil, prosopis glandulosa, shrub patch dynamics, shrub proliferation, soil depth}, doi = {10.1890/11-1193.1}, url = {/files/bibliography/12-026.pdf}, author = {Dawn M. Browning and Danielle Duni and Andrea S. Laliberte and A. Rango} }