Semiarid Vineyards Research Articles

High diversity of ants in Australian vineyards

AbstractAnt diversity in Australia is exceptionally high compared to other regions of the world, with semiarid regions being the most species‐rich. Ants perform numerous ecological functions and have been used in various biomonitoring programs. The role of ants in vineyards is unclear although other studies have focussed on controlling the invasive Argentine ant, Linepithema humile (Mayr), which significantly promotes mealybug and scale insect densities. While ants have been surveyed in a range of habitats throughout the continent, little is known about the diversity of ants in Australian vineyards. In this study, 147 native ant species were identified with pitfall trapping from 50 vineyards distributed in five regions in Victoria and South Australia. Species richness, compositional similarities and assemblage structure varied within and across regions although the ant fauna in semiarid vineyards was the most diverse. Linepithema humile was only detected in seven vineyards in one region. High ant diversity in vineyards could potentially contribute to ecosystem services, including biological control, and provide insurance to ecosystem functioning. Vineyards and other perennial agroecosystems could be important in maintaining invertebrate biodiversity particularly in a structurally diverse agricultural landscape.

Labile Organic Matter, Aggregates, and Stratification Ratios in a Semiarid Vineyard with Cover Crops

Under semiarid Mediterranean climatic conditions, scarce attention has been given to the utilization of permanent cover crops (PCCs) in vineyard agroecosystems to increase soil organic C (SOC) and to improve the soil quality. We evaluated the feasibility of two permanent cover crops (resident vegetation, RV, and ‘Aurora gold’ blue fescue [Festuca longifolia Thuill.] vegetation, FV) to increase SOC and to improve the soil quality with respect to conventional tillage in a semiarid vineyard. We studied the influence of these management practices on the labile organic matter fractions (particulate organic C [POC], potentially mineralizable N [PMN], and water‐soluble C [WSC]), on the water aggregate stability (WAS) and on the stratification ratios (SRs) of these soil attributes. The field experiment was conducted on a fine‐loamy, mixed, thermic Typic Haploxerept soil in a vineyard located in the La Rioja region (northeast Spain). Soil samples were collected from four soil layers (at depths of 0–2.5, 2.5–5, 5–15, and 15–25 cm) during June 2008, 4 yr after cover crop establishment. The SOC content, POC, WSC, PMN, and WAS were measured. At a depth of 0 to 2.5 cm, the cover crops increased SOC, POC, WSC, PMN, and WAS. The C sequestration rates for RV and FV were 1.34 ± 0.31 and 1.52 ± 0.70 Mg ha−1 yr−1, respectively. Regression analyses indicated positive strong correlations among all parameters monitored. The SRs of the SOC, POC, and PMN were >2 in all depth ratios calculated and therefore were efficient indicators of the soil quality improvement caused by the PCCs. In a semiarid Mediterranean vineyard, a PCC has proven to be an effective strategy to enhance the SOC and to improve the soil quality in the short term.