Altering Rainfall Timing and Quantity in a Mesic Grassland Ecosystem: Design and Performance of Rainfall Manipulation Shelters

Abstract

Global climate change is predicted to alter growing season rainfall patterns, potentially reducing total amounts of growing season precipitation and redistributing rainfall into fewer but larger individual events. Such changes may affect numerous soil, plant, and ecosystem properties in grasslands and ultimately impact their productivity and biological diversity. Rainout shelters are useful tools for experimental manipulations of rainfall patterns, and permanent fixed-location shelters were established in 1997 to conduct the Rainfall Manipulation Plot study in a mesic tallgrass prairie ecosystem in northeastern Kansas. Twelve 9 x 14-m fixed-location rainfall manipulation shelters were constructed to impose factorial combinations of 30% reduced rainfall quantity and 50% greater interrainfall dry periods on 6 x 6-m plots, to examine how altered rainfall regimes may affect plant species composition, nutrient cycling, and above-and belowground plant growth dynamics. The shelters provided complete control of growing season rainfall patterns, whereas effects on photosynthetic photon flux density, nighttime net radiation, and soil temperature generally were comparable to other similar shelter designs. Soil and plant responses to the first growing season of rainfall manipulations (1998) suggested that the interval between rainfall events may be a primary driver in grassland ecosystem responses to altered rainfall patterns. Aboveground net primary productivity, soil CO 2 flux, and flowering duration were reduced by the increased interrainfall intervals and were mostly unaffected by reduced rainfall quantity. The timing of rainfall events and resulting temporal patterns of soil moisture relative to critical times for microbial activity, biomass accumulation, plant life histories, and other ecological properties may regulate longerterm responses to altered rainfall patterns.

Tallgrass prairie soil fungal communities are resilient to climate change

“…Each RaMP comprises a fixed-location, 14 x 9 m rainout shelter over intact, native grassland (Fay et al 2000(Fay et al , 2003. Each shelter consists of a clear (UV transparent) polyethylene roof to exclude natural rainfall, two 4 m 3 reservoirs to collect and store up to 10 cm of rainfall, and an overhead irrigation system to reapply (at 2.5 cm hr -1 ) the stored rainfall.…”

“…Each shelter consists of a clear (UV transparent) polyethylene roof to exclude natural rainfall, two 4 m 3 reservoirs to collect and store up to 10 cm of rainfall, and an overhead irrigation system to reapply (at 2.5 cm hr -1 ) the stored rainfall. Thus, the shelter design allows for complete and efficient experimental control of the quantity, timing and variability in rainfall inputs (Fay et al 2000). Rainfall is applied to each RaMP using 13 sprinkler heads to ensure …”

“…Therefore, concerted manipulations of multiple environmental drivers are essential. The primary goal of this contribution was to utilize an existing experiment that has simultaneously manipulated temperature and precipitation timing in a tallgrass prairie ecosystem (Fay et al 2000(Fay et al , 2003. Previous studies using this experimental infrastructure have observed responses in plant growth and aboveground annual net primary production (ANPP) Fay et al 2011), leaf carbon assimilation (Fay et al 2011), soil CO 2 efflux (Harper et al 2005;Fay et al 2011;Zeglin et al 2013), as well as soil microbial community biomass and exoenzyme activities (Zeglin et al 2013).…”

Decreased water limitation under elevated CO 2 amplifies potential for forest carbon sinks

“…but rainfall manipulation experiments demonstrate that plant responses to rainfall can also depend significantly on the timing of rainfall distribution (17,18). Recent theoretical work also highlights the complexity of plant dependence on water.…”

Response of N 2 O emission to water and nitrogen addition in temperate typical steppe soil in Inner Mongolia, China

“…2). Some studies have shown that the seasonal distribution of rainfall affects ecosystem productivity, biological diversity, and soil nutrients cycling (Fay et al, 2000;Weltzin et al, 2003;Peng et al, 2012), as well as the biological activity of microbes and plants. Thus, nitrification and denitrification processes driven by microbial activity and N availability must be affected.…”