-
大熊猫(Ailuropoda melanoleuca)是全球生物多样性保护的旗舰物种与伞护物种。过去几十年大熊猫保护取得了举世瞩目的成就,但该物种仍然面临繁殖力弱、存活率低、栖息地破碎化等问题[1]。根据全国第四次大熊猫调查的结果,仍有30%的大熊猫栖息地质量有问题[2]。由于自然隔离和人为干扰,大熊猫栖息地被隔离成33个斑块,面积小于10 000 hm2的斑块有9个,栖息地破碎化将给野生大熊猫种群的生存、繁衍带来威胁[3]。大相岭山系有大熊猫38只[2],是六大山系中种群数量最少的[4]。该区域栖息地面积小、破碎化程度高、人类活动干扰严重,亟待加强保护[4]。伴随大熊猫国家公园的建立,栖息地恢复工作是未来大熊猫国家公园保护管理工作的重点。
大熊猫是森林类型的物种,竹类资源、森林起源以及遮蔽条件是影响大熊猫生境利用的主要因素[5]。森林中的乔木为大熊猫提供躲避、休息以及巢穴。林下竹子作为大熊猫主要的食物来源,是大熊猫生存的基础。已有研究表明,森林群落乔木层郁闭度对林下植物的生长起重要作用[6-9],乔木是森林群落恢复过程中重要的生物因子[10],乔木层通过对光的透射、反射和吸收,直接影响林下光照的强度和分布,而光照对于绝大多数森林树种而言,是决定更新个体能否生存和生长的关键[11]。乔木层郁闭度对竹子的高度、基径和密度等生长发育具有重要的影响[7,12]。因此,研究乔木层结构特征与林下竹子生长指标之间的关系是栖息地恢复的基础,对提升大熊猫栖息地质量、保护大熊猫及全球生物多样性具有至关重要的作用。
泥巴山筇竹是非常典型的大熊猫取食竹,是大相岭山系泥巴山区域大熊猫最主要的取食来源。而有关泥巴山筇竹的研究少之又少。基于此,本研究选择大相岭山系的大熊猫栖息地作为研究对象,针对大熊猫栖息地森林群落乔木层结构特征与林下泥巴山筇竹生长指标开展调查,定量分析两者之间的关系,并建立大熊猫栖息地森林群落乔木层特征与林下泥巴山筇竹生长关系的模型,以期为该区域大熊猫栖息地恢复提供量化依据。
-
结果显示(表1):每个泥巴山筇竹样方内泥巴山筇竹平均发笋量为(3.06±4.58)株,死竹平均株数为(10.83±8.05)株,活竹平均株数为(41.71±26.28)株,一年生泥巴山筇竹平均基径为(7.53±1.86)mm,一年生泥巴山筇竹平均高度为(175.90±49.72)cm,多年生泥巴山筇竹平均基径为(8.41±1.77)mm,多年生泥巴山筇竹平均高度为(199.78±55.67),笋平均基径为(8.35±2.05),笋平均高度为(134.09±57.12)cm。每个植物样方内乔木平均高度为(7.42±2.61)m,乔木平均株数为(36.66±20.86)株,乔木平均郁闭度为(0.42±0.20)。
乔木平均高度/m
Average height of trees (m)乔木株数/株
Number of trees乔木层郁闭度
Tree canopy density发笋量/株
Shooting quantity死竹株数/株
Number of dead bamboo plants活竹株数/株
Number of live bamboo plants7.42±2.61 36.66±20.86 0.42±0.20 3.06±4.58 10.83±8.05 41.71±26.28 一年生竹基径/mm
Basal diameter of annual bamboo (mm)一年生竹高度/cm
Height of annual bamboo (cm)多年生竹基径/mm
Basal diameter of perennial bamboo (mm)多年生竹高度/cm
Height of perennial bamboo (cm)笋基径/mm
Basal diameter of bamboo shoots (mm)笋高度/cm
Bamboo shoot height (cm)7.53±1.86 175.90±49.72 8.41±1.77 199.78±55.67 8.35±2.05 134.09±57.12 -
单因素方差分析的结果表明,乔木郁闭度对一年生、多年生和泥巴山筇竹笋的基径的影响差异显著(p<0.05),对泥巴山筇竹活竹株数、死竹株数和笋高度的影响差异极显著(p<0.01)。乔木株数对泥巴山筇竹死竹株数的影响差异显著(p<0.05),对泥巴山筇竹发笋量和活竹株数的影响差异极显著(p<0.01)。乔木平均高度对泥巴山筇竹发笋量和多年生竹基径的影响差异显著(p<0.05),对一年生泥巴山筇竹高度和基径、多年生泥巴山筇竹高度的影响差异极显著(p<0.01)(表2)。
乔木层指标
Tree layer index泥巴山筇竹指标
Qiongzhuea multigemmia indexdf F P 乔木层郁闭度
Tree layer density发笋量Shooting quantity df 1 =3, df 2 =198 0.831 0.478 活竹株数Number of live bamboo plants df 1 =3, df 2 =200 13.59 <0.001*** 死竹株数Number of dead bamboo plants df 1 =3, df 2 =178 4.54 0.004** 一年生竹高度Height of annual bamboo df 1 =3, df 2 =12 2.473 0.064 一年生竹基径Basal diameter of annual bamboo df 1 =3, df 2 =152 2.697 0.048* 多年生竹高度Height of perennial bamboo df 1 =3, df 2 =197 1.543 0.205 多年生竹基径Basal diameter of perennial bamboo df 1 =3, df 2 =197 3.684 0.013* 笋高度Bamboo shoot height df 1 =3, df 2 =100 4.289 0.007** 笋基径Basal diameter of bamboo shoots df 1 =3, df 2 =100 3.326 0.023* 乔木株数
Number of trees发笋量Shooting quantity df 1 =3, df 2 =198 8.432 <0.001*** 活竹株数Number of live bamboo plants df 1 =3, df 2 =200 8.447 <0.001*** 死竹株数Number of dead bamboo plants df 1 =3, df 2 =178 3.159 0.026* 一年生竹高度Height of annual bamboo df 1 =3, df 2 =152 1.124 0.341 一年生竹基径Basal diameter of annual bamboo df 1 =3, df 2 =152 0.493 0.688 多年生竹高度Height of perennial bamboo df 1 =3, df 2 =197 1.397 0.245 多年生竹基径Basal diameter of perennial bamboo df 1 =3, df 2 =197 1.789 0.15 笋高度Bamboo shoot height df 1 =3, df 2 =100 1.879 0.138 笋基径Basal diameter of bamboo shoots df 1 =3, df 2 =100 0.584 0.627 乔木平均高度
Average height of trees发笋量Shooting quantity df 1 =2, df 2 =109 4.625 0.011* 活竹株数Number of live bamboo plants df 1 =2, df 2 =201 0.766 0.466 死竹株数Number of dead bamboo plants df 1 =2, df 2 =201 2.056 0.131 一年生竹高度Height of annual bamboo df 1 =2, df 2 =153 7.51 <0.001*** 一年生竹基径Basal diameter of annual bamboo df 1 =2, df 2 =153 7.261 <0.001*** 多年生竹高度Height of perennial bamboo df 1 =2, df 2 =198 7.556 <0.001*** 多年生竹基径Basal diameter of perennial bamboo df 1 =2, df 2 =198 3.747 0.025* 笋高度Bamboo shoot height df 1 =2, df 2 =101 1.096 0.338 笋基径Basal diameter of bamboo shoots df 1 =2, df 2 =101 0.136 0.873 注:*为P<0.05,**为P<0.01,***为P<0.001。
Note: * means P<0.05, * * means P<0.01 and * * * means P<0.001.Table 2. Variance analysis of growth index of Qiongzhuea multigemmia in different groups of tree layer structure characteristics
-
根据方差分析结果,挑选对泥巴山筇竹生长指标有显著性影响的因子,将其作为模型的固定效应。因此,可将乔木株数和乔木平均高度2个因子,保留在泥巴山筇竹发笋量模型中;将乔木层郁闭度和乔木株数2个因子,均保留在活竹株数和死竹株数模型中;将乔木平均高度因子保留在一年生泥巴山筇竹平均高度模型中;将乔木层郁闭度和乔木平均高度2个因子,均保留在一年生和多年生泥巴山筇竹平均基径模型中;将乔木平均高度因子保留在多年生泥巴山筇竹平均高度模型中;将乔木层郁闭度因子保留在泥巴山筇竹笋高度和笋基径模型中。
采用赤池信息准则(AIC)指标来比较不同模型间的模拟效果。AIC值越小,表明模拟效果越好。结果表明,所挑选的主要因子模拟效果均好于没有显著性影响的因子的模型拟合效果。使用不同的有显著性的因子作为固定效应,其混合模型的精度不同。在泥巴山筇竹发笋量、活竹株数和死竹株数模型中,以乔木株数作为固定效应的模型AIC值均最小,拟合精度均最高;在一年生平均基径模型中,以乔木平均高度作为固定效应的模型AIC值最小,拟合精度最高;在多年生平均基径模型中,以乔木层郁闭度作为固定效应的模型AIC值最小,拟合精度最高(表3)。
八月竹指标
Bamboo index乔木层指标
Tree layer index固定效应截距
Fixed effect
intercept固定效应系数
Fixed effect
coefficient随机效应截距
Random effect
intercept残差
ResidualAIC 发笋量
Shooting quantity乔木株数
Number of trees−0.9527 0.0191* 4.5231 — 842.5 乔木平均高度
Average height of trees0.5194 −0.2051 6.9233 — 844.3 活竹株数
Number of live bamboo plants乔木层郁闭度
Tree canopy density4.0594*** −0.5317 0.7887 — 2392.1 乔木株数
Number of trees3.9996*** −0.0061** 0.3052 — 2388.5 死竹株数
Number of dead bamboo plants乔木层郁闭度
Tree canopy density2.3415*** −0.4207 0.2906 — 1362.1 乔木株数
Number of trees2.5597*** −0.0115** 0.2565 — 1354.7 一年生平均高度
Average annual height乔木平均高度
Average height of trees170.3135*** −0.2313 1923.8400 867.5400 1625.2 一年生平均基径
Annual average basal diameter乔木层郁闭度
Tree canopy density7.8847*** −0.8754 2.8744 1.1910 598.7 乔木平均高度
Average height of trees8.4845*** −0.1248 2.7424 1.1820 597.3 多年生平均高度
Perennial average height乔木平均高度
Average height of trees154.7610*** 5.8200* 1863.3830 1065.0000 2105.2 多年生平均基径
Perennial average basal diameter乔木层郁闭度
Tree canopy density8.4666*** −0.8716 2.2288 1.0310 717.5 乔木平均高度
Average height of trees7.5236*** 0.0651 2.2396 1.0293 717.7 笋高度
Bamboo shoot height乔木层郁闭度
Tree canopy density192.3600*** 11.8800 2109.6200 1070.5600 2109.7 笋基径
Basal diameter of bamboo shoots乔木层郁闭度
Tree canopy density8.7150*** −1.8043 1.7355 2.4800 439.2 注:*为P<0.05,**为P<0.01,***为P<0.001。
Note: * means P<0.05, * * means P<0.01 and * * * means P<0.001.Table 3. Model fitting results of Qiongzhuea multigemmia
结果显示,泥巴山筇竹活竹株数、死竹株数、一年生平均高度、一年生平均基径、多年生平均高度、多年生平均基径、笋高度和笋基径模型的固定效应截距均达到极显著水平(P<0.001),说明乔木层结构特征各参数对模型变化影响极显著。乔木株数的固定效应系数对泥巴山筇竹发笋量模型变化影响显著(P<0.05),乔木株数的固定效应系数对泥巴山筇竹活竹和死竹株数模型变化影响均极显著(P<0.01),乔木平均高度的固定效应系数对多年生泥巴山筇竹平均高度模型变化影响显著(P<0.05)(表3)。
随着乔木株数和乔木平均高度的增加,泥巴山筇竹发笋量均呈减少的趋势;随着乔木层郁闭度和乔木株数的增加,泥巴山筇竹活竹株数和死竹株数均呈减少的趋势;随着乔木平均高度的增加,一年生泥巴山筇竹平均高度呈减少的趋势;随着乔木层郁闭度和乔木平均高度的增加,一年生泥巴山筇竹平均基径均呈减少的趋势;随着乔木平均高度的增加,多年生泥巴山筇竹平均高度和基径均呈增加的趋势;随着乔木层郁闭度的增加,泥巴山筇竹笋高度呈增加的趋势,多年生平均基径、笋基径呈减少的趋势(表3)。
Study on the Relationship between Tree Layer and Understory Qiongzhuea multigemmia of Forest Community in Giant Panda Habitat
doi: 10.12172/202302060001
- Received Date: 2023-02-06
- Available Online: 2023-04-18
- Publish Date: 2023-10-25
-
Key words:
- Giant Panda habitat /
- Habitat restoration /
- Forest canopy /
- Qiongzhuea multigemmia /
- Generalized linear mixed model
Abstract: In order to explore the correlation between the tree layer of forest community and understory Giant Panda feeding bamboo in the giant panda habitat, the tree layer structure characteristics of forest community in Daxiangling Giant Panda habitat and the growth index of understory Qiongzhuea multigemmia under forest were investigated by using line transects and quadrat methods, and the generalized linear mixed model (GLMM) and linear hybrid model (LMM) were constructed and analyzed. The results showed that: (1) The canopy density of tree layer had significant effects on the basal diameter of annual, perennial and bamboo shoots, the number of live and dead bamboo, the height of bamboo shoots; the number of trees had significant effects on the number of bamboo shoots, the number of dead bamboo and live bamboo; the average height of trees had significant effects on the number of bamboo shoots, height and base diameter of annual and perennial bamboos. (2) The number of bamboo shoots increased with the increase of number and average tree height; the number of live and dead bamboo decreased with the increase of canopy density and number of trees; the average height of annual bamboo decreased with the increase of the average height of trees; the average base diameter of the annual bamboo decreased with the increase of the canopy density of tree layer and the average height of the trees; the average height and base diameter of the perennial bamboo increased with the increase of the average height of the trees; the height of bamboo shoot increased with the increase of canopy density of tree layer; the average base diameter of perennial bamboo and shoot decreased with the increase of canopy density of tree layer. This study provided a quantitative basis for the restoration of the Giant Panda habitat in this region.