Aboveground net primary production dynamics in a northern Chihuahuan Desert ecosystem

Abstract

Aboveground net primary production (ANPP) dynamics are a key element in the understanding of ecosystem processes. For semiarid environments, the pulse-reserve framework links ANPP to variable and unpredictable precipitation events contingent on surficial hydrology, soil moisture dynamics, biodiversity structure, trophic dynamics, and landscape context. Consequently, ANPP may be decoupled periodically from processes such as decomposition and may be subjected to complex feedbacks and thresholds at broader scales. As currently formulated, the pulse-reserve framework may not encompass the breadth of ANPP response to seasonal patterns of precipitation and heat inputs. Accordingly, we examined a 6-year (1999-2004), seasonal record of ANPP with respect to precipitation, soil moisture dynamics, and functional groups in a black grama (Bouteloua eriopoda) grassland and a creosotebush (Larrea tridentata) shrubland in the northern Chihuahuan Desert. Annual ANPP was similar in the grassland (51.1 g/m(2)) and shrubland (59.2 g/m(2)) and positively correlated with annual precipitation. ANPP differed among communities with respect to life forms and functional groups and responses to abiotic drivers. In keeping with the pulse-reserve model, ANPP in black grama grassland was dominated by warm-season C(4) grasses and subshrubs that responded to large, transient summer storms and associated soil moisture in the upper 30 cm. In contrast, ANPP in creosotebush shrubland occasionally responded to summer moisture, but the predominant pattern was slower, non-pulsed growth of cool-season C(3) shrubs during spring, in response to winter soil moisture accumulation and the breaking of cold dormancy. Overall, production in this Chihuahuan Desert ecosystem reflected a mix of warm-temperate arid land pulse dynamics during the summer monsoon and non-pulsed dynamics in spring driven by winter soil moisture accumulation similar to that of cool-temperate regions.

Effects of fire on belowground biomass in Chihuahuan desert grassland

“…Several major biotic zones converge in this area including Chihuahuan Desert grassland and shrubland, Great Plains grassland, Piñon-Juniper woodland, Colorado Plateau shrub-steppe, and riparian vegetation along the middle Rio Grande. Average annual temperature is 13.28C with the highest average temperatures in June (33.48C) and the lowest average in January (1.68C) (Muldavin et al 2008). Annual precipitation is highly variable and averages 250 mm with the majority falling as large summer monsoon events from June through September (Gosz et al 1995, Pennington andCollins 2007); sporadic precipitation occurs throughout the winter and spring as a consequence of frontal systems from the west and northwest.…”

“…Grasslands dominated by B. eriopoda occupy large areas throughout the northern Chihuahuan Desert where they intergrade with shrub-dominated vegetation and may co-dominate with Bouteloua gracilis (Jameson 1962, Dick-Peddie 1993, Brown and Smith 2000, Kroël-Dulay et al 2004. Aboveground production of B. eriopoda grasslands is strongly driven by seasonal (monsoon) precipitation and temperature (Gosz and Gosz 1996, Muldavin et al 2008), but unlike aboveground responses the relationship between belowground production, climate and disturbance remains poorly understood (Ladwig et al 2012).…”

Soil enzyme responses to varying rainfall regimes in Chihuahuan Desert soils

“…Mean annual precipitation (MAP) over the past 22 years is 240 6 14 mm, with ;60% of MAP occurring in larger, summer monsoon events from June to September (Gosz et al 1995, Pennington andCollins 2007, Petrie et al v www.esajournals.org 2014). Plant production is aligned with precipitation and perennial grass production responds primarily to summer monsoon precipitation both locally and regionally (Muldavin et al 2008, Notaro et al 2010). …”

Implications of climatic heterogeneity for conservation of the Lesser Prairie‐Chicken (Tympanuchus pallidicinctus)

“…Important dietary components include seeds, acorns, and cultivated grains during fall and winter (Davis et al 1981, Riley et al 1993, forbs during spring (Davis et al 1981), and invertebrates during summer (Jamison et al 2002). Invertebrate abundance is positively related to forb cover (Jamison et al 2002) which in turn responds to grazing (McNaughton 1985) and to precipitation, particularly that which occurs during the winter preceding, and the spring of, the nesting season (Muldavin et al 2008, Xia et al 2010.…”