Nonlinear shifts in infectious rust disease due to climate change

Jonathan C B Nesmith,Andrew M Latimer,Claire E Willing,Joan Dudney,John J Battles,Adrian J Das

doi:10.1038/s41467-021-25182-6

Abstract

Range shifts of infectious plant disease are expected under climate change. As plant diseases move, emergent abiotic-biotic interactions are predicted to modify their distributions, leading to unexpected changes in disease risk. Evidence of these complex range shifts due to climate change, however, remains largely speculative. Here, we combine a long-term study of the infectious tree disease, white pine blister rust, with a six-year field assessment of drought-disease interactions in the southern Sierra Nevada. We find that climate change between 1996 and 2016 moved the climate optimum of the disease into higher elevations. The nonlinear climate change-disease relationship contributed to an estimated 5.5 (4.4–6.6) percentage points (p.p.) decline in disease prevalence in arid regions and an estimated 6.8 (5.8–7.9) p.p. increase in colder regions. Though climate change likely expanded the suitable area for blister rust by 777.9 (1.0–1392.9) km2 into previously inhospitable regions, the combination of host-pathogen and drought-disease interactions contributed to a substantial decrease (32.79%) in mean disease prevalence between surveys. Specifically, declining alternate host abundance suppressed infection probabilities at high elevations, even as climatic conditions became more suitable. Further, drought-disease interactions varied in strength and direction across an aridity gradient—likely decreasing infection risk at low elevations while simultaneously increasing infection risk at high elevations. These results highlight the critical role of aridity in modifying host-pathogen-drought interactions. Variation in aridity across topographic gradients can strongly mediate plant disease range shifts in response to climate change.

Highlights

Range shifts of infectious plant disease are expected under climate change
Mean annual vapor pressure deficit (VPD) increased from 9.74 ± 0.87 to 11.15 ± 1.0 (Fig. 2b) and mean minimum temperatures increased from −2.48 ± 0.68 °C to −1.24 ± 0.80 °C (Fig. 2d)
Though many factors likely contributed to this decline, here we focus on the combination of host–pathogen interactions, a water availability gradient across elevation, and spatially varying drought impacts. We suggest that these abiotic-biotic interactions modified the disease distribution through two pathways: A) fewer alternate hosts at high elevations dampened infection probabilities, even as warmer conditions ameliorated the historic climatic constraints on spread and B) greater water deficit in arid regions decreased prevalence, an effect that was likely amplified by drought (Figs. 5, 6c, d)

Summary

Introduction

Range shifts of infectious plant disease are expected under climate change. As plant diseases move, emergent abiotic-biotic interactions are predicted to modify their distributions, leading to unexpected changes in disease risk. As infectious diseases extend beyond the leading edge of their range in response to climate change, contractions may occur at the trailing edge where conditions become too hot and dry[11,18] Infectious diseases have both high and low-temperature tolerances and moisture requirements, or climate optima[7,19,20]. This nonlinear, hump-shaped relationship indicates that climate change can shift the location of climate optima in space, leading to both increases and decreases in disease prevalence across the geographic range[21,22,23] (Fig. 1a,a.1). As disease distributions shift in space, biotic interactions with host populations may cause increases or decreases in prevalence relative to climate

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Conclusion