Forecasting community dynamics: the mast system

Forecasting community dynamics: the mast system

Funding: NSF-DEB, NASA-AIST

PIs: Jim Clark, Jen Swenson, Roland Kays (NC Museum of Natural History, NCSU)

A summary

The impact of climate change on biological communities will depend on interactions involving the local habitat and the species that interact with one another—as each species responds directly to climate it indirectly affects all of the species with which it interacts. These species interactions complicate efforts to predict climate effects, because each species experiences habitat complexity at a different scale—from flightless insects to large vertebrates.

This study will determine how tree fecundity varies with tree size and habitat, including masting cycles and aging.  The effects of climate variation in space and between years helps us understand the role of environmental variation.

Our study aims to evaluate the contribution of mast supply to consumer abundances.  It will evaluate how diverse communities of species monitored in NEON respond together with food supply, in the form of masting shrubs and trees, and large mammal surveys.

Data sets we add to NEON include seed traps, to evaluate individual tree attributes (include cone production for conifers), and camera traps, to quantify activity of large vertebrates.  Remotely-sensed imagery and the NEON airborne observatory will be used to characterize habitat diversity.

Results of this analysis will be used to evaluate community change and reorganization, including prediction and attribution of tree population response to climate change, climate risk by species and habitat and how it is shared across species groups. New data on large mammals and seed production from NEON sites will be made available to the community. The study will engage the public through citizen assisted identification of animal images.

What makes MASTIF different?

A large number of important efforts report on statistical properties taken from published studies, focusing on metrics like mean mast production, mean mast intervals, and coefficient of variation.  Meta-analysis builds statistics from statistics that come from published studies.

A number of key questions on forest response to global change require estimates for individual trees, as part of a single integrated analysis.  How does the masting schedule for each individual tree depend on individuals nearby?  Are individuals of different species co-masting?  What is the space-time covariance structure faced by a mast consumer with limited capacity to forage widely and a restricted diet?

Rather than focus on statistics from statistics, MASTIF is integrating raw data from across the continent into a single posterior distribution of responses at the individual, population, and community scales.  This approach requires data fusion of seed-trap and crop-count data, collected by a range of methods, but each linked to the processes of tree maturation and fecundity.

Additional  specifics

Field sites are described here, together with those of collaborators on the synthesis of mast data.

Methods: Information regarding data types, including seed traps and crop counts count is here.  Camera trap design is discussed here.  Model fitting is here.

Results are being made available on a web site under development here.

MASTIF has a citizen science component as the MASTIF project on iNaturalist.

Modeling framework

Clark, J.S., C. Nunes, and B. Tomasek. 2019. Foodwebs based on unreliable foundations: spatio-temporal masting merged with consumer movement, storage, and diet. Ecological Monographs, in press. Appendix.