Rocky desertification expansion and ecological degradation are prominent issues in karst regions, arising from the combined effects of carbonate bedrock fragility and human disturbance. Traditional management approaches are constrained by high costs and limited adaptability. While lithophytic mosses, as pioneer colonists on bare rocks, deliver critical soil-water conservation functions, their growth dynamics and functional responses to microenvironments remain inadequately understood. This study systematically investigated the cascading mechanisms linking rock attitude, microenvironment, moss growth, and soil-water conservation across different land-use types (cropland, grassland, orchard), rock orientations (east, south, west, north, up), and vertical positions (top, middle, bottom) in a typical karst area. Results revealed that rock attitude significantly drove moss growth and functional differentiation: north-facing, slopes <40 degrees, and rock bottoms supported optimal moss thickness (11.81 mm), biomass (5.51 & times; 10(3) kg hm(-2)), water-holding (54.18 & times; 10(3) kg hm(-2)), and soil stabilization capacity (12.56 & times; 10(3) kg hm(-2)). Moss performance was superior in orchards, exhibiting 3.2 times the water retention of croplands and 2.3 times the soil stabilization of grasslands. Higher humidity favored moss growth, and critical microenvironmental thresholds were identified: chlorophyll a+b (0.59 mg g(-1)) and water-holding rate (861.42%) peaked under >50% relative humidity and 30-50% full sunlight, whereas high irradiance coupled with low humidity suppressed growth. A chain effect was evident: rock attitude governs the microclimate and hydro-nutrient conditions, which in turn regulate moss growth and its consequent soil-water conservation functions, with land use acting as a key external driver. This work establishes theoretical foundation and practical strategies for moss cultivation and restoration in karst regions.