The Temporal Ecology Lab focuses on the question: How does global change alter the temporal assembly and disassembly of communities? In particular we study how humans have fundamentally altered how organisms experience time through changes to habitat structure, disturbance cycles, and the global climate system. Our long-term goal is to better understand the mechanisms that drive global change impacts on species, communities and ecosystems so that we can reliably forecast ecological responses and aid in mitigating unwanted consequences. We are especially lucky that this goal lets us tackle a lot of interesting fundamental science.
In addition to the below work, the lab also works on winegrapes, which we now cover in a whole website that includes some of our favorite resources on understanding climate change: State of Wine.
What is the temperature response to climate change by plants and animals?
Biological time has been reshaped by anthropogenic warming. This is highlight by shifts in phenology, the study of the different stages of plant growth and the transitions between them. The phenology of many plants and animals is primarily driven by temperature and decades of lab studies highlight a common temperature response curve, where response rates increase with warmer temperatures until some optimum then crash or stall. Yet global change biology has struggled to adapt this common response to outside the lab. Our lab is working to overcome this disconnect with more realistic models of temperature response, and by interrogating how responses compare across methods and scales to identify drivers of variation.
We recently highlighted major variation due to the complexity of measuring ‘time’ as climate change accelerates biological responses. We showed that dozens of studies finding that sensitivity to temperature has declined with warming can be predicted from the non-linearity of temperature responses. Read more in Global Change Biology
Temperature is not the only fundamental driver of phenology, as daylength may also play a critical role, and could limit species responses to warming. Across species, we’ve used a massive meta-analysis of temperature x daylength experiments to show that winter temperatures are actually the strongest controllers of spring phenology in tress. We’re now examining how strongly evolutionary history shapes responses to these cues. Across latitudes, results from our own common garden and a cross-continental meta-analysis of similar studies both confirm that tree phenological responses are strongly plastic in the spring and determined by local adaptation in the fall. Building on this, work led by Ailene Ettinger and Daniel Buonaiuto both highlighted how phenological events cannot be considered alone, as reproductive events—both their length and dispersal mode–shape the timing of growth.
Read more about this work in:
Ettinger*, A.K., Chamberlain*, C.J., Buonaiuto*, D. M., Morales-Castilla*, I., Flynn*, D.F.B., Savas*, T., Samaha*, J. & E. M. Wolkovich. 2020. Winter temperatures predominate in spring phenological responses to warming. Nature Climate Change: 10 (12), 1137-1142. (link)
Buonaiuto*, D. M., Morales-Castilla*, I., E. M. Wolkovich. 2020. Reconciling competing hypotheses regarding flower–leaf sequences in temperate forests for fundamental and global change biology. New Phytologist. (link)
Wolkovich, E. M., Chamberlain*, C.J., Buonaiuto*, D. M., Ettinger*, A.K. & I. Morales-Castilla.* 2022 How interactive effects of temperature and photoperiod shape plant phenology responses to warming. New Phytologist: 235: 1719-1728. (link)
Buonaiuto*, D. M. & E. M. Wolkovich. 2021. Differences between flower and leaf phenological re- sponses to environmental variation drive shifts in spring phenological sequences of temperate woody plants. Journal of Ecology: (109): 2922–2933. (link)
Ettinger*, A.K., Buonaiuto*, D. M., Chamberlain*, C.J., Morales-Castilla* & E. M. Wolkovich. 2021. Spatial and temporal shifts in photoperiod with climate change. New Phytologist: 230 (2), 462-474. (link)
Better understanding phenology may also help us predict the winners and losers as climate change, as our lab has found that how well species track environmental change phenological connects to fitness. These studies, however, often consider phenology as a singular plant trait-—one that may critically influence plant performance and spread but is not tied to other major traits. In contrast, plant phenology could be considered as one of many correlated traits making up a plant’s trait syndrome. The lab is testing whether considering phenology as a critical plant trait correlated with other major functional traits can help understand assembly.
You can read more about this work in (just list the journal names (in italics) and link to each of the PDFs that go with them — listed below). Deirdre Loughnan has led a major study of how phenology correlates with other functional traits across North American forests. Hear more about her work here.
Wolkovich, E. M. & A. K. Ettinger. 2014. Back to the future for plant phenology research. New Phytologist 203: 1021–1023. (Commentary) (link)
Flynn*, D. F. B. & E.M. Wolkovich. 2018. Temperature and photoperiod drive spring phenology across all species in a temperate forest community. New Phytologist. doi.org/10.1111/nph.15232 (link)
How does intra- and inter-annual time assemble communities?
In many ways our above work provides critical building blocks to our lab’s greater aim—forecasting how phenology affects interspecific interactions. Our research program is extending community assembly theory, which has focused mainly on space and inter-annual timescales, to the intra-annual—phenological—timescale.
The lab’s work in this area began when Lizzie was a postdoc and worked on a framework for how intra-annual time and phenology could underlie invader success—a fundamental question in community assembly. Working with Megan Donahue, she has extended it to a more general theory to show that tracking must trade-off with other traits for stable communities, and that environmental change can reshape the balance of equalizing versus stabilizing mechanisms. For this work, we adapted the storage effect model to include environmental tracking and non-stationary environments (environments that shift over time), and we plan to continue developing it to guide research.
You can read more about this work in:
Wolkovich, E. M. & Donahue, M. 2021. How phenological tracking shapes species and communities in non-stationary environments. Biological Reviews: 10.1111/brv.12781. (link)
Eyster, H.* & Wolkovich, E. M. 2021. Comparisons in the native and introduced ranges reveal little evidence of climatic adaptation in germination traits. Climate Change Ecology: doi.org/10.1016/j.eco- chg.2021.100023 (link)
Wolkovich, E. M. & E. E. Cleland. 2014. Phenological niches and the future of invaded ecosystems with climate change. AoB Plants doi:10.1093/aobpla/plu013. (link)
Wolkovich, E. M., Davies, T. J., Schaefer, H., Cleland, E. E., Cook, B. I., Travers, S. E. , Willis, C. G. & C. C. Davis. 2013. Temperature-dependent shifts in phenology contribute to the success of exotic species with climate change. American Journal of Botany 100(7): 1407-1421. (link)
Wainwright, C. E., E. M. Wolkovich & E. E. Cleland. 2012. Seasonal priority effects: implications for invasion and restoration in a semi-arid system. Journal of Applied Ecology 49(1): 234-241. (Recommended by Faculty of 1000) (link)
Wolkovich, E. M. & E. E. Cleland. 2011. The phenology of plant invasions: A community ecology perspective. Frontiers in Ecology & the Environment 9(5): 287-294. (Recommended by Faculty of 1000) (link)
These new models highlight how our research program is leading global efforts to integrate two critical parts of climate change—non-stationary environments and discrete events—into community assembly. During her PhD Cat Chamberlain showed frost events have increased across Europe with climate change, and highlighted how this can reshape plant growth. These discrete events result from climate change shifting both phenology and climatic events at once. The damage of events is dependent on the phenological stage—for example, frost damage peaks at budburst, and heat wave damage is highest at flowering—resulting in a complex interplay of climate drivers and effects, which we call `climate hazards.’ Working with Frederik Baumgarten, the lab is developing a new program of experiments and models to understand and predict how these hazards impact plant growth.
You can read more about this work in:
Chamberlain*, C.J., Cook, B.I., Morales-Castilla*, I. & E. M. Wolkovich. 2020. Climate change reshapes the drivers of false spring risk across European trees. New Phytologist: 229 (1), 323-334 (link)
Chamberlain*, C.J & E. M. Wolkovich. 2021. Late spring freezes coupled with warming winters alter temperate tree phenology and growth. New Phytologist: (231) 987–995. (link)
Wolkovich, E. M., Cook, B. I., McLauchlan, K. K. & T. J. Davies. 2014. Temporal ecology in the Anthropocene. Ecology Letters 17(11): 1365–1379. (link)
How is climate changing reshaping trophic interactions?
Events are also shaped across trophic levels. My lab has been instrumental in advancing the study of trophic mismatch, both through advancing the underlying conceptual theory and through more robust meta-analyses, with new work in my lab showing clade-level—not trophic level—differences may underlie current reports of global trophic mismatch.
You can read more about this work in:
Kharouba, H. M., Ehrlen, J., Gelman, A., Bolmgren, K., Allen, J. M., Travers, S. & E. M. Wolkovich. 2018. Global shifts in the phenological synchrony of species interactions over recent decades. PNAS: Apr 2018, ; DOI: 10.1073/pnas.1714511115 (link)
Kharouba, H. M. & E. M. Wolkovich. 2020. Disconnects between ecological theory and data in phenological mismatch research. Nature Climate Change: https://doi.org/10.1038/s41558-020-0752-x (link)
Open science needed to advance global change research
Progress in global change research over the last 20 years has come alongside a distinct shift towards synthetic work. Previously, excellent ecological research was underpinned by observations, experiments, and models often conducted by the same researcher or research group. Today, however, the best work includes syntheses of these three pillars of research through time and space, combining data, methods, and insights from disparate experiments, multiple long-term datasets, and theories.
Data sharing, often mandated in other fields, is generally low in ecology, and code for models and analyses is rarely included with publications. Such a lack of transparency forces ecologists to work without key data and analytical resources, retards collaboration, and impairs research with strong conservation relevance by making most findings difficult to study in depth, build upon, or reproduce. Although ‘open ecology’ appears to have potentially large benefits for the discipline, the vast majority of ecologists have never shared their data for a variety of perceived and real issues.
Working with Mary O’Connor, Jim Regetz and Lizzie put together an article that outlines and addresses the major concerns and advantages of data and code-sharing, and address the skill sets and logistical needs at the individual and lab-based level. You can download it here. Additionally Lizzie has talked about this issue in pieces at Nature here and here and Science Careers, served on the Scientific Advising Board of Dryad and is now on the steering committee for the Environmental Data Science RCN, which is hosting summits to build this community (check out the 2023 meeting)
Our lab works to make all our data public. Check out our data and code management plan here.
Learn more about past research in the lab here