A rainout shelter design for intercepting different amounts of rainfall

Abstract

Field manipulative experiments represent a straightforward way to explore temporal relationships between annual precipitation and productivity. Water exclusion usually involves the use of rainout shelters, which are in general formed by a complete roof that intercepts 100% of the rainfall and require complicated mechanisms to move the shelter into place. The rainout-shelter design described here is a fixed-location shelter with a roof consisting of bands of transparent acrylic that blocks different amounts of rainfall while minimally affecting other environmental variables. We constructed thirty 3.76-m shelters in an arid steppe near Río Mayo, Argentina (at 45°41'S, 70°16'W), to impose 30%, 55%, and 80% of rainfall interception. We tested the effectiveness of the design by collecting all the intercepted water in storage tanks and we evaluated changes in soil water content with the time domain reflectometry technique. We also measured soil water content in regular grids to assess the magnitude of the edge effect. We analysed the microclimate impact of the shelters by measuring photosynthetically active radiation and air and soil temperature inside and outside shelters. We did not detect significant differences between the observed and the expected rainfall interception for the 30% and 55% interception treatments but the 80% shelters intercepted 71% of incoming rainfall, which was significantly (P<0.05) lower than the expected value. Soil water content was significantly (P<0.05) higher in the control plots than in the plots with rainout shelter at all dates, except in January (summer). Radiation was not affected by the 30% interception treatment, but the roof with the largest number of acrylics bands (80% interception treatment) reduced incident radiation throughout the day by 10%. Air and soil temperatures were lower under than outside the shelters during the period of highest radiation but the opposite occurred with low radiation but with smaller differences. The two characteristics of the shelter, fixed design and low cost, allow for proper replication in space, which is required in ecological field experiments.

Post-Fire Seedling Recruitment and Morpho-Ecophysiological Responses to Induced Drought and Salvage Logging in Pinus halepensis Mill. Stands

“…Similarly to previous studies [29,30], we built rain-exclusion shelters formed by a 2 × 2 m metal frame that supported V-shaped clear methacrylate bands with no UV filter (Barlocast; Faberplast S.L., Madrid, Spain), which covered 20% of the surface to intercept the same percentage of natural water supply by rain. To prevent surface runoff water from entering, we dug trenches (20 cm deep) along the entire shelters to intercept runoff water.…”

Warming reduces the growth and diversity of biological soil crusts in a semi-arid environment: implications for ecosystem structure and functioning

“…To achieve a rainfall reduction similar to that forecasted, we set up passive rainfall shelters (RSs) based upon the design described by Yahdjian & Sala [62]. Each RS has an area of 1.44 m 2 (1.2 Â 1.2 m), and a mean height of 1 m. Each roof has an inclination of 208 and is composed of three gutters of methacrylate that cover approximately 37 per cent of the surface, connected to containers that collect the excluded water (see the electronic supplementary material, appendix S2).…”

Water controls on nitrogen transformations and stocks in an arid ecosystem

“…To exclude precipitation from the plots, we installed 48 2.5 3 2.5 m fixed-location rainout shelters in November of 2006 that passively blocked incoming rainfall following the design by Yahdjian and Sala (2002). Similar rainout shelters are being used in many studies from the Patagonian Steppe, the Arctic Tundra, the short grass steppe, the Mediterranean and Californian grasslands to the southwestern rangelands of the US (Heisler-White et al 2008, Adler et al 2009, Fiala et al 2009, Levine et al 2010, Rao and Allen 2010, Matías et al 2011, Talmon et al 2011.…”

“…Shingles were molded from ACRYLITE FF with high light transmission (.92% PAR transmitted) and less than 3% change in light transmission over a 10-yr period (CYRO Industries, Parsippany, NJ). Shelters have minimal effects on the microenvironment, and only a small edge effect on soil water content of approximately 20 cm (Yahdjian and Sala 2002), hence we excluded the edge area from our sampling.…”