Soil nitrogen availability varies with plant genetics across diverse river drainages

Abstract

Understanding covariance of plant genetics and soil processes may improve our understanding the role of plant genetics in structuring soils and ecosystem function across landscapes. We measured soil nitrogen (N) and phosphorus (P) availability using ion exchange resin bags within three river drainages across Utah and Arizona, USA. The three drainages spanned more than 1,000 km in distance, 8°of latitude, and varying climatic regimes, but were similarly dominated by stands of Populus fremontii (S. Watts), P. angustifolia (James), or natural hybrids between the two species. Soil N availability was consistently greater in P. fremontii stands compared to P. angustifolia stands, and hybrid stands were intermediate. However, we found that the influence of overstory type on soil P availability depended on the river drainage. Our study suggests that, even with a near doubling of mean soil N availability across these drainages, the relative geneticbased effects of the dominant plant on N availability remained consistent. These results expand upon previous work by: 1) providing evidence for linkages between plant genetic factors and ecosystem function across geographic scales; and 2) indicating that plant genetic-based effects on nutrient dynamics in a given ecosystem may differ among nutrients (e.g., N vs. P).

Plant genetic effects on soils under climate change

“…For example, plant genotype can affect N cycling and availability in ecosystems ranging from riparian forests (Schweitzer et al 2004(Schweitzer et al , 2008a(Schweitzer et al , b, 2011Fischer et al 2007Fischer et al , 2010, to oak woodlands Hunter 2002, 2003), to aspen forests (Madritch et al 2009). The distribution of genotypes that affect nutrient cycles create patterns in soil N availability that are consistent across geographic distances over 1,000 km, and elevations up to 1,000 m (Schweitzer et al 2004;Madritch et al 2009;Fischer et al 2010).…”

“…For example, plant genotype can affect N cycling and availability in ecosystems ranging from riparian forests (Schweitzer et al 2004(Schweitzer et al , 2008a(Schweitzer et al , b, 2011Fischer et al 2007Fischer et al , 2010, to oak woodlands Hunter 2002, 2003), to aspen forests (Madritch et al 2009). The distribution of genotypes that affect nutrient cycles create patterns in soil N availability that are consistent across geographic distances over 1,000 km, and elevations up to 1,000 m (Schweitzer et al 2004;Madritch et al 2009;Fischer et al 2010). Studies on ecosystem C dynamics have similarly demonstrated widespread patterns whereby the genetics of foundation plant species strongly influence ecosystem C uptake and aboveground net primary productivity (ANPP; Crutsinger et al 2006;Fischer et al 2006Fischer et al , 2007Lojewski et al 2009;Grady et al 2011), net ecosystem productivity (Souza et al 2011;Breza et al 2012), leaf litter decomposition (Schweitzer et al 2004;Madritch and Hunter 2002;Madritch et al 2006;LeRoy et al 2007), soil CO 2 efflux (Fischer et al 2007;Lojewski et al 2012), and belowground C allocation (Fischer et al , 2007Lojewski et al 2012) (Fig.…”

“…Because these compounds are an important pathway through which plant litter decomposition and N mineralization are affected, these higher level effects of genes are referred to as community and ecosystem phenotypes (Schweitzer et al 2004(Schweitzer et al , 2008aLeRoy et al 2007;Iason et al 2012). Similarly, genetically linked changes in plant C:N ratios, lignin, N, and P concentrations are correlated with both litter decomposition and nutrient availability at the plant-soil interface (e.g., Treseder and Vitousek 2001;Schweitzer et al 2004;Chapman et al 2006a;Fischer et al 2010). Root chemical quality, in particular N concentration, can influence root litter decomposition and nutrient release to soils (e.g., Classen et al 2007).…”

Effect of alien riparian vegetation and its removal on a highly endemic river macroinvertebrate community

“…Dense stands of invasive trees along river margins change habitat structure, fire regimes, hydrology, and water quality, which in turn changes light regime, temperature, oxygen levels, leaf litter input, nutrient cycling, pH, turbidity, soil chemistry, erosion processes and sedimentation Davies and Day 1998;Maridet et al 1998;Fischer et al 2010). Alien trees, especially Acacia spp., have dense canopies that shade out habitats and prevent growth of indigenous under storey plants such as sedges, reeds and grasses, altering availability and quality of marginal habitats (Kinvig and Samways 2000;Samways et al 1996) and soil (Fischer et al 2010), causing a loss of marginal vegetation often used by benthic macroinvertebrate larvae as nursery or feeding areas or for shelter, and by adults as perches or oviposition sites. Alien riparian vegetation therefore affects both riparian and aquatic habitats.…”

Restoration of invaded Cape Floristic Region riparian systems leads to a recovery in foliage-active arthropod alpha- and beta-diversity

“…For example, removal of IAPs alters canopy characteristics, which directly affects the interior environments of ecosystems (i.e., temperature, humidity, and radiation), this, in turn, leads to changes in arthropod richness and abundance (Ziesche and Roth 2008). Apart from microclimate, altered architectural habitat complexity (Schowalter and Crossley 1988) and changes in plant nutritional quality (Fischer et al 2010), IAP removal may also influence arthropod communities by limiting their dispersal ability by creating isolated patches (Schowalter and Crossley 1988).…”