CANCELLED - Biodiversity in a flash: monitoring grassland biodiversity and ecosystem functioning using remote sensing

Background/Question/Methods

Functional diversity is commonly used to characterize ecosystem health due to its role in promoting ecosystem productivity, stability and resilience. Current approaches often rely on species mean trait values, under the assumption that traits should vary more between than within species. However, interactions with the environment are based at the level of the individual, and environmental change leads to shifts in community trait distributions due to both species turnover and individual plasticity. Because of the importance of intraspecific variability for predicting outcomes of disturbance for ecosystem functioning, new methods for capturing traits in individuals, rather than species, are necessary for informing ecosystem management. Here, we examine the utility of functional trait measures derived from hyperspectral imagery to reveal community change and predict ecosystem functioning. Specifically, we assess 1) the relative importance of intraspecific trait variability for measuring community change, and 2) the utility of spectrally-derived functional diversity for predicting changes to functions. We employ high resolution imagery of a natural grassland community subject to a multiyear drought and grazing manipulation in Boulder, Colorado, USA. We subsequently measure indicators of key ecosystem functions, including soil fertility and plant productivity, to understand the role of community traits in driving ecosystem multifunctionality.

Results/Conclusions

Preliminary results reveal an interactive effect of drought and grazing on spectrally-derived functional diversity and soil moisture levels. Spectrally-derived functional diversity was lowest in plots that were both grazed and subjected to drought, while those that were grazed and received irrigation sustained the highest levels of diversity. Soil moisture content also did not show systematic decreases under the drought treatment, but instead depended on plot-level diversity with more diverse plots sustaining higher soil moisture levels even in the drought treatment. Analyses of the remaining ecosystem functions (soil fertility and productivity) will be completed this spring, alongside additional trait analyses using PLSR, and will allow us to explicitly relate community-level trait changes to consequences for ecosystem functioning. Altogether, these results highlight the potential for significant influence of human land-use and climate change on vegetation communities, and encourage further exploration to explain the interactions between diversity, drought, and soil properties.