A reciprocal transplant experiment within a climatic gradient in a semiarid shrub‐steppe ecosystem: effects on bunchgrass growth and reproduction, soil carbon, and soil nitrogen

Abstract

We investigated the effect of climate change on Poa secunda Presl. and soils in a shrub‐steppe ecosystem in south‐eastern Washington. Intact soil cores containing P. secunda were reciprocally transplanted between two elevations. Plants and soils were examined, respectively, 4.5 and 5 years later. The lower elevation (310 m) site is warmer (28.5 °C air average monthly maximum) and drier (224 mm yr−1) than the upper elevation (844 m) site (23.5 °C air average monthly maximum, 272 mm yr−1). Observations were also made on undisturbed plants at both sites. There was no effect of climate change on plant density, shoot biomass, or carbon isotope discrimination in either transplanted plant population. The cooler, wetter environment significantly reduced percent cover and leaf length, while the warmer, drier environment had no effect. Warming and drying reduced percent shoot nitrogen, while the cooler, wetter environment had no effect. Culm density was zero for the lower elevation plants transplanted to the upper site and was 10.3 culms m−2 at the lower site. There was no effect of warming and drying on the culm density of the upper elevation plants. Culm density of in situ lower elevation plants was greater than that of the in situ upper elevation plants. Warming and drying reduced total soil carbon 32% and total soil nitrogen 40%. The cooler, wetter environment had no effect on total soil C or N. Of the C and N that was lost over time, 64% of both came from the particulate organic matter fraction (POM, > 53 µm). There was no effect of warming and drying on the upper population of P. secunda while exposing the lower population to the cooler, wetter environment reduced reproductive effort and percent cover. With the warmer and drier conditions that may develop with climate change, total C and N of semiarid soils may decrease with the active fraction of soil C also rapidly decreasing, which may alter ecosystem diversity and function.

The Role of Plants in the Effects of Global Change on Nutrient Availability and Stoichiometry in the Plant-Soil System

“…In contrast, warming in dry environments, such as those of continental, Mediterranean, and dry tropical biomes, can increase soil drought, exacerbating limitations of water and nutrients (Link et al, 2003;Allison and Treseder, 2008). Plants respond by activating mechanisms for water conservation, which can frequently increase C-nutrient ratios in photosynthetic tissues (Sardans et al, 2008b(Sardans et al, , 2008c.…”

The Potential Impact of Climate Change on Soil Properties and Processes and Corresponding Influence on Food Security

“…In a study of soils in a semi-arid steppe, Link et al [64] observed that soil warming and drying led to a 32% reduction in soil C over a five year time period, a much more rapid reduction in soil C than reductions that have been observed due to increased tillage. Modeling of C responses to climate change in Canada predicted small increases in aboveground biomass in forest and tundra ecosystems but larger decreases in soil and litter pools, for an overall increase in atmospheric C [65].…”

Different effects of warming and cooling on the decomposition of soil organic matter in warm–temperate oak forests: a reciprocal translocation experiment

“…Several field experimental approaches have been used to investigate potential effects of global warming on the ecosystem, for example field warming using external heat inputs (Luo et al 2001;Melillo et al 2002), observing differences in ecosystems along natural climatic gradients (Conant et al 2000;Rodeghiero and Cescatti 2005), or transferring ecosystem components to a new site with different climatic conditions (Breeuwer et al 2010;Hart 2006;Link et al 2003;Rey et al 2007). Especially, reciprocal treatment (simulating climate cooling) to that of warming can strengthen the conclusions drawn from warming treatment in which temperature has a dominant effect on soil-plant processes (Hart and Perry 1999).…”

“…Especially, reciprocal treatment (simulating climate cooling) to that of warming can strengthen the conclusions drawn from warming treatment in which temperature has a dominant effect on soil-plant processes (Hart and Perry 1999). Reciprocal soil translocation experiments have been widely used to understand the potential effects of climate change on C and nitrogen (N) cycles (Hart 2006;Hart and Perry 1999;Link et al 2003;Rey et al 2007;Zimmermann et al 2009) and soil microbial communities (Budge et al 2011).…”