Influence of Abrams M1A1 Main Battle Tank Disturbance on Tallgrass Prairie Plant Community Structure

Abstract

The Department of Defense's Range and Training Land Assessment program provides information and recommendations to range managers regarding the condition of training lands. This information is used to assist in scheduling training areas and in monitoring the effectiveness of rehabilitation projects. Fort Riley Military Installation is a major training reservation located in the Flint Hills of northeastern Kansas, within the tallgrass prairie ecosystem. A randomized complete block design composed of three treatments (M1A1 Abrams tank traffic during wet and dry soil conditions, and a nontrafficked control) with three replications was established in each of two soil types, a silty clay loam and a silt loam soil, on Fort Riley in 2003. Disturbance was created by driving the tank for five circuits in a figure-eight pattern during either during wet or dry soil conditions. Two additional experimental treatments were added during the study: five additional tank passes on one-half of each figure eight in 2004 and burning in 2006. Two areas, a curve and straightaway, within each traffic intensity (and later, burn treatment) subplot were designated for sampling. Aboveground biomass, species composition, and ground cover were measured during each growing season. Recovery of grass and total aboveground biomass in silty clay loam soil was delayed for curve areas and following disturbance in wet soil conditions, respectively. Species composition and ground cover continued to exhibit significant disturbance effects in 2007, with greatest damage observed for repeated traffic under wet soil conditions. Fire effects on vegetation were variable and generally greater for undisturbed control plots than for disturbed areas. The tallgrass prairie typically is considered to be among the most resilient of military training lands, but our research suggests that resiliency is dependent upon soil type and training conditions, and may require longer periods of recovery than previously thought. Resumen El programa de entrenamiento y valoración de Tierras del Departamento de Defensa provee información y recomendaciones a los manejadores de pastizales sobre la condición de las tierras de entrenamiento. Esta información se utiliza en la selección de áreas de entrenamiento así como para el monitoreo de la efectividad de los proyectos de rehabilitación. Las instalaciones militares del Fuerte Riley es una importante reservación de entrenamiento localizada en Flint Hills al noreste de Kansas, dentro de los ecosistemas de praderas de pastos altos. Un diseñ o de bloques al azar, compuesto de tres tratamientos (Tráfico de tanques Abrams M1A1 bajo condiciones de suelo húmedo y seco, y un área control sin tráfico), con tres repeticiones se establecieron en dos sitios con diferente tipo de suelo, un suelo limo-arcilloso y un suelo limoso en el Fuerte Riley en 2003. El disturbio fue creado mediante la conducción del tanque en cinco circuitos en forma de ocho durante condiciones de suelo húmedo o suelo seco. Se incluyeron otros dos tratamientos experimentale...

Evaluation of Bulk Density and Vegetation as Affected by Military Vehicle Traffic at Fort Riley, Kansas

“…Surface compaction may recover after winter freeze and thaw cycles (Halvorson et al, 2003), but recovery of the vegetation to its original status may take longer (Althoff et al, 2009). To evaluate the lingering effects of multiple-pass trafficking on soil surface compaction as well as future growth and composition of vegetation, bulk density and biomass data were also collected in the spring and summer (following the fall trafficking) from the trafficked and untrafficked locations.…”

“…However, it is necessary to determine whether there were significant differences between bulk densities before and after trafficking. To this end, a data set was generated using equation 1, in which bulk density differences between disturbed (trafficked) and undisturbed (control or untrafficked) were expressed as a fraction of the control (Althoff et al, 2009):…”

Mixedgrass vegetation is tolerant to a short‐term but not season‐long access mat use during mitigation of industrial traffic

“…Once mats were removed, vegetation was observed to promptly regrow, likely from grass rhizomes protected below the soil surface (Althoff et al, 2009), a process further enhanced by plant stress and/or damage to crowns (Liddle, 1974). Notably, this response was evident here as an increase in shallow root mass, and occurred after short duration (6 weeks) mat placement as well as early season (E6) direct traffic.…”

“…Traffic disturbances can reduce plant cover and change grassland composition (Althoff et al, 2009). With extensive mortality under extended mat placement, regrowth may not occur from vegetative bud banks (i.e., plant crowns or root buds) (Aguilera & Lauenroth, 1993), necessitating re‐establishment from the persistent seed bank or seed entry (Desserud et al, 2010).…”

“…This process is often associated with changes from a late‐seral native grassland to one comprised of early colonizer, weedy, or invasive species. Previous studies indicate the seedbank of native grasslands in western Canada contain abundant non‐native species (Willms & Quinton, 1995) that emerge following soil disturbance (Desserud et al, 2010), which could heighten the risk of community change after matting (AEP, 2016a; Althoff et al, 2009; Desserud et al, 2010; Milchunas et al, 2000; Wilson, 1988).…”