Wesche, K; Nadrowski, K; Retzer, V: Habitat engineering under dry conditions: The impact of pikas (Ochotona pallasi) on vegetation and site conditions in southern Mongolian steppes, Journal of Vegetation Science, 18(5), 665-674 (2007)
Question: Does ecosystem engineering by small mammals have a significant influence on vegetation patterns in the arid steppe vegetation of southern Mongolia?
Location: Gobi Altay Mountains, southern Mongolia
Methods: We assessed the impact of the small lagomorph Ochtona pallasi on plant community composition, soil nutrient levels and biomass production in montane desert steppes in southern Mongolia. Data were derived from vegetation relev├ęs, harvests of above-ground standing crop and a bioassay, followed by analyses of soil and plant nutrients.
Results: Although the local climate is arid with <150 mm annual precipitation, clear evidence of allogenic ecosystem engineering was found. Plant communities on burrows differed from those on undisturbed steppe in that they contained more species of annuals and dwarf shrubs, and a greater abundance of the important fodder grass Agropyron cristatum. Standing crop and nutrient concentrations were higher for plants growing on burrow soil. In situ measurements and a pot experiment showed that this effect was related to increased levels of soil nutrients (P, K, N) rather than moisture availability.
Conclusions: The study confirms that O. pallasi positively influences soil nutrient levels on its burrows, which leads to increased grassland productivity even under dry conditions. Thus, O. pallasi does not deteriorate site conditions, and the need for presently applied pest control schemes aimed at this species should be reassessed.

last modified 2009-05-13