Synchronous species responses reveal phenological guilds: Implications for management

Authors: Browning, Dawn; CRIMMINS, THERESA - University Of Arizona; James, Darren; Spiegal, Sheri; Levi, Matthew; ANDERSON, JOHN - New Mexico State University; Peters, Debra

Submitted to: Ecosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2018
Publication Date: 9/5/2018
Citation: Browning, D.M., Crimmins, T., James, D.K., Spiegal, S.A., Levi, M.R., Anderson, J.P., Peters, D.C. 2018. Synchronous species responses reveal phenological guilds: Implications for management. Ecosphere. 9(9):e02395. https://doi.org/10.1002/ecs2.2395.
DOI: https://doi.org/10.1002/ecs2.2395

Interpretive Summary: Benchmarks for seasonal activity patterns in plants - or plant phenology – are effective indicators of plant responses to environmental conditions such as temperature and rainfall that are important for food security, human health, and biodiversity. Most of our understanding of phenology comes from studies or observations made in mesic or temperate environments; less is known about desert plant phenology. We examined a 23-year dataset documenting timing of leaf-out, flower and fruit production for 16 species including ten grass forage species. Our analysis detected distinct and different patterns for grasses and shrubs and also revealed groups of species that synchronously leafed out or produced fruit across years. We called these groups of species that behave similarly over time “phenological guilds.” There are several ways researchers, managers, and decision makers can benefit from understanding phenological guilds. Phenological guilds can potentially increase efficiency of plans for meeting management objectives, assist with managing livestock herds to avoid species of management concern, and possibly guide formulation of new grass seed mixtures for ecological restoration.

Technical Abstract: Phenological studies are critical for understanding the ability of terrestrial ecosystems to respond to directional changes in climate. However, species responses are challenging and resource-intensive to study; thus developing guilds of similar species responses would prove useful. 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-LTER research site to identify patterns in the start of three phenophases – leaf-out, flower, and fruit – of 16 widely occurring species in the arid southwestern U.S. We expand our knowledge of phenological profiles beyond reproductive phenology for these C3 and C4 species in water-limited ecosystems and explore the concept of phenological guilds as we set out to examine consistency in timing of phenophase onset across sites and years, and to determine coherence in timing of phenophase onset in groups of species across sites among years in order to elucidate guilds of species responses. We implemented 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 (i.e., guilds). The six species of C3 shrubs demonstrated greater consistency in timing of all phenophases relative to C4 grasses. Cluster analysis revealed six groups of species-site observations demonstrating high within-year concordance in timing of leaf-out and first fruit across variable site conditions and rainfall years. The six clusters 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 define phenological guilds as groups of species that exhibit similar patterns in the timing of seasonal transitions over time. Use of phenological guilds can improve the efficiency of ecosystem monitoring, predictive models of ecosystem cues driving phenological events, and land management outcomes.