Habitat Assessment And Water Quality Analysis For Low Order Streams Under Different Land Use In Liangshui And Maoershan, Heilongjiang, China

To understand the differences in habitat features and water quality of low order streams inlandscapes under different land uses, survey was conducted within 3 streams at LiangshuiNational Reserve for Korean Pine Old-growth (with landscape of old growth forest), andMaoershan National Park (3 streams within landscape of second growth forests and croplands,respectively). The biological features (including suspending algae, periphyton algae) andphysical-chemical features (temperature, turbidity, dissolved oxygen (DO), pH, NH₄⁺-N, NO₃^--N, pO₄^3--P, total nitrogen(TN) and total phosphorus(TP)) and fine particulate organicmatter(FPOM) and coarse particulate organic matter(CPOM))and hydrology character (streamwidth, depth and velocity of flow)were analyzed/measured. Comparisons of stream waterquality and stream habitat under different land use were made, and analyzed the seasonalchange of stream water quality.The streams in Liangshui under old growth forests were best in term of habitat features, whilethe worst habitat features were found with streams in landscapes under cropland land use inMaoershan. Streams in old growth forests in Liangshui were found with more stable streambedsubstrate for invertebrates, evenly positioned pools and riffles, greater variation of pool size,Jess stream bed sedimentation, and with more sinuous stream channels, stable riparian areawith greater plant coverage. Streams in second growth forests were dominated by riffles, withless stable streambed substrate, with more sedimentation influence, relatively stable riparianareas which were disturbed frequently by human activities. Streams in cropland were foundwith instable streambed substrate, heavily affected by sedimentation, highly channelized anddevegetated riparian areas.The water quality of the old growth forest streams were better than that of the second growthforest streams, the water quality of the second growth forest streams were better than that ofthe cropland streams. CPOM,NH₄⁺ and DO was higher and stream width and depth werelower in the forest streams. Greater concentration of TP,TN and pH were found withstreams under old growth forests. Except in springtime, lower temperature, suspendedalgae,periphyton algae and concentration of NO₃^-,TDIN,PO₄^3- were found in the oldgrowth forest streams. The cropland stream had the greater concentration of NO₃^-,TDIN,TN,PO₄^3-,N/P,temperature,suspended algae,periphyton algae in summer and autumn.With the change of seasons, in the while, the stream water quality displayed certain changetrend. The concentration of and NO₃^- and the ratio of N/P increased, DO decreased. Insummer, some indices such as temperature,turbidity,NH₄⁺-N,PO₄^3--P,FPOM,streamwidth,stream depth were highest which influenced by precipitation. The range of change in water quality indexes was different under different land use. The range of change in theconcentration NO₃^- and periphyton algae and the ratio N/P was greater and in CPOM waslower in the cropland streams. The range of change in turbidity and the concentration NO₃^- waslower in the old growth forest streams.All mentioned above, the stream habitat and water quality varied greatly with different land-using. The partial chemic index of streams under the old-growth forest were high, the waterquality of streams were best in the old-growth forest stream, followed by the second- growthforest streams, then the cropland streams in summer and autumn; the habitat of streams underold-growth forests were better than that of the second- growth forest streams, and the habitat ofthe old-growth and second- growth forest streams were better than that of cropland stream inspring, summer and autumn. The effect of land-using and disturbance of riverside on thestream habitat and water quality was important.