Abstract

Shaqlawa Natural Rangeland, located in the Erbil Governorate of the northern region of Iraq, is an important ecological landscape with varied topographical and microclimatic conditions. The aim of this study was to assess the diversity and composition of the soil seed bank and its implication for forage productivity on the northern and southern facades of the rangeland. There were 1,087 germinated seeds from 36 species, with Fabaceae and Poaceae dominating as the most common families. The seed bank comprised mainly native, C₃ annual forbs that possessed high regenerative ability and ecological adaptability. Slope aspect and altitude had an evident impact on species richness and functional diversity. North slopes, with their more humid and cooler microclimate, were more favorable for higher diversity in plant functional characteristics like photosynthetic pathways, life forms, and taxonomic families. The number of monocotyledonous species was lower than dicotyledons, and no C₄ species were encountered.
Maximum weed richness was at North × High Elevation, and maximum native species richness was at North × Medium Elevation. These findings indicate that north slopes and higher elevations favor more diversity of annual species, particularly weeds, and lower areas favor perennial species. These processes can be used to inform land management to enable native species restoration and the control of invasive species in rangeland systems.
Although both annuals and monocots were more common at higher elevations, dicot and perennial species dominated at middle to lower elevations. Remarkably, weed cover was more prevalent at higher elevation, mainly on north-facing slopes, an indicator that is critical of the need for invasive plant management. In general, the findings support the central role played by topographic and microclimatic gradients in the modulation of soil seed bank diversity and present useful data to inform sustainable rangeland management, renovation planning, and biodiversity conservation planning.