Assessing the impacts of droughts on small ruminants grazing areas and respective soil hydrological responses

Abstract

Abstract Recent studies affirm that climate change is affecting areas worldwide, particularly long droughts, which would transform many fertile territories into degraded areas. This could imply significant impacts and natural hazards influencing both water and soil resources and, subsequently, plant species composition and biodiversity. One of the affected land use and related type of ecosystem are the pastures of the hills with small ruminants (sheep and goats). However, there is a lack of studies aimed to develop integrated hydrological and climate approaches to assess these possible impacts in countries such as Romania. Therefore, this study aims to evaluate drought impacts on hills pastures occupied by small ruminants (SRs) based on the analysis of aridity indices, rainfall simulation experiments, and field surveys (e.g., soil profiles and vegetation transects) in an experimental plot located in the Curvature Subcarpathians of Romania. Preliminary results show high monthly variability of aridity, vertical dehydrated layers in the main soil types (chernozems exhibiting shrinkage and swelling processes), degraded herbaceous vegetation, and high runoff coefficient for bare soils. At the hillslope scale, vegetation, SRs, and water occurrence (e.g., low runoff coefficients and high infiltration rates) are strongly affected by droughts, especially during August and September. The intensification of SRs grazing in these areas (under dry conditions) amplifies the drought effects on the environment (e.g., soil compaction, grass depletion, water scarcity). Our field observations do not support SRs grazing as a major driving factor for land degradation, but unsustainable SRs grazing can drastically induce changes in seasonally available soil water content under arid conditions.