Characteristics Of Species Diversity, Biomass And Nutrients Of Undergrowth In A Subtropical Evergreen Broadleaf Forest In Dashan, Southern Anhui

Understory vegetation including shrubs, herbs and vines under the forest canopy, is an important part of forest ecosystems. The distribution and growth characteristics of understory vegetation is limited by stand characteristics. Understory vegetation is constantly changing understory microenvironment through life activities, thus the stability of the entire forest ecosystem, successional development and biodiversity plays an important role. This study from October 2012 to July 2013, in Shitai County, Anhui cents apartment mountain, seasonal dynamics sampling conducted observation in the study forest biodiversity, biomass and nutrients, such as by lower natural evergreen broad-leaved forest vegetation, access to the preliminary results are as follows.1 seasons change of understory vegetation diversityTree species seedlings represent a significant advantage in the shrub layer. In spring and autumn, the number of understory vegetation species in shrub layer is slightly higher than in summer. In three seasons, the important values mean greater than 10% of the species have eight kinds, Woodwardia fern in the understory herbaceous layer has an absolute advantage. Spring, summer, autumn three seasons, species diversity indices of species richness and Shannon-Wiener index was less than shrub species diversity index, but the fall and spring evenness index is higher than the shrub layer. Species diversity indices were the highest in the fall.2 standard sample understory vegetation diversityEmpty plots in Shannon-Wiener index and Margalef richness index Pielou index showed a significant positive correlation, and high nitrogen plots in the Shannon-Wiener index and Margalef richness index Pielou index showed a significant positive correlation, while high Shannon-Wiener index and Margalef richness index showed the nitrogen plus phosphorus treatment plots a significant positive correlation between diversity index only low nitrogen treatment no correlation. Blank samples with high nitrogen plus phosphorus treatment plots Margalef richness index was significantly negatively correlated. Low nitrogen plots Margalef richness index and nitrogen plus phosphorus treatment plots Pielou index was significantly correlated. High nitrogen plots Margalef richness index and nitrogen plus phosphorus treatment plots of Shannon-Wiener index and Pielou index was significantly correlated.3 shrub biomassOptimal biomass models nine shrubs are optimal biomass Sarcandra glabra model Y = 3.372 + 3.61 7 (D2H) - 0.038(D2H)2; eyrei biomass optimal model Y = 339.562D4119; Camellia biomass optimal model Y = 17.479 - 73.826D + 104.017 D2; obtusiloba biomass optimal model Y = -3.817 + 0.184 H + 0.022 H2; Cinnamomum subavenium biomass optimal model Y = 17.339-246.92D2 +372.784 D3; red Nan biomass optimal model Y = 55.803 - 403.091D + 884.25 D2 - 367.73D3; moments leaf biomass Itea optimal model Y = 7.428 + 0.008 (Ac) - 6.47 E-07 (Ac)2 + 3.39 E-11 (Ac)3; red lighter than biomass optimal model Y = - 0.342 + 25.703 D - 9.202D2 + 7.726 D3; bayberry leaf biomass Distylium optimal model Y = 4.481 + 1.356 (D2H) -0.014 (D2H)2 + 3.61 E-05 (D2H)3.4 leaf nutrient concentrationC concentration range of nine kinds of leaf species is 427.31 - 471.61 g ? kg-1; N concentration range of 9.47 ～ 13.32 g ? kg-1; P concentration range of 0.38 ~ 1.08 g ? kg-1g ? kg-1; K concentration the range of 8.36 ～ 16.21 g ? kg-1; Ca concentration range of 3.16 ～ 7.99 g ? kg-1; Mg concentration range of 3.61 ～ 7.73 g ? kg-1.5 leaf nutrient contentRange 9 kinds of blades per unit leaf area of the C content is 40.42 ~ 76.37g ? m-2; N content in the range of 0.99 ～ 1.98g ? m-2; P content in the range of 0.05 ～ 0.16 g ? m-2; K content in the range of 1.21 ~ 1.86 g ? m-2; Ca content in the range of 0.50 ~1.16 g ? m’2; Mg content in the range of 0.60 ~ 0.95 g ? m-2. N, P, K, Ca, Mg content of leaves per unit area averages were 1.55,0.09,1.53,0.73 and 0.74gg ? m-26 leaf nutrient relations with SLALeaf specific leaf area (SLA) and potassium concentrations (p = 0.031) were significantly positively correlated at the 0.05 level, and calcium concentration (p = 0.050) were significantly positively correlated at the 0.05 level, (p = 0.005) concentrations of Mg at 0.01 level a significant positive correlation with C (p = 0.069), N (p = 0.492), P (p = 0.981) and the ratio of leaf area no significant correlation . Specific leaf area and leaf area C (p = 0.000), N content (p = 0.007) were significant negative correlation at the 0.01 level, while the P (p = 0.292), K (p = 0.374), Ca (p = 0.622), Mg (p = 0.412) no significant correlation between the levels.7 herbaceous layer of nutrientsAboveground herbaceous layer nutrient concentrations C concentrations were 419.40 ± 60.12 g ? kg-1, N concentration of 11.36 ± 4.02 g ? kg-1, P concentration of 0.55 ± 0.17g·kg-1, potassium concentration 14.49±7.29 g·kg-1, the calcium concentration 5.32±2.95 g·kg-1, Mg concentrations of 8.84±4.50 g·kg-1; underground part of the herb layer C concentration of nutrient concentrations were 411.50±71.90 g·kg-1, N concentration of 8.76±2.17 g·kg-1, P concentration of 0.54±0.19 g·kg-1, potassium concentration 10.59±8.21 g·kg-1, the calcium concentration 2.92±2.81 g·kg-1, Mg concentration of 7.02±3.37 g·kg-1; aboveground concentration of each nutrient elements were higher than the underground part of the ground portion of the nitrogen and phosphorus higher than the underground part, but the carbon-nitrogen ratio and phosphorus were lower than the aerial parts of the underground part.