Spatial and temporal patterns in seed predation as revealed by reciprocal experiments and video surveillance in neighbouring beech and spruce forests     

Vanessa Marie Ellingsen  Johan Asplund 《Scandinavian Journal of Forest Research》2017,32(2):105-114

European beech and Norway spruce are late successional and competitive species meeting each other in southern Norway. Beech is predicted to expand northwards with increased temperature, implying increased competition between the two tree species. Seed survival is a key process in this competition and here we estimate detection times and predation rates of beech and spruce seeds in adjacent beech and spruce forests by combining quantitative and qualitative approaches based on reciprocal seed predation experiments and video surveillance. These experiments were repeated over two growing seasons, and by using a video-surveillance technique, we were able to precisely reveal seed detection times and high seed predation rates, up to 15 seeds?min^?1, with bank vole and chaffinch as main predators. Moreover, the two main predators were different in their seed preferences, that is, beech seeds were exclusively removed or predated by the vole, while the finch consumed spruce seeds only. As we show high predation rates, even small variations in seed predator population densities would impact the regeneration success of beech and spruce. Because the highest predation rates were recorded for spruce seeds, it is likely that this will alter the competitive balance between the two tree species in favour of beech.  相似文献   

甘肃兴隆山青杄林树干径向生长及其对气象因子的响应          下载免费PDF全文

陈徵尼  仲怡铭  王翠英  凌雷  吴国宏 《西北林学院学报》2022,37(6):62-67

以甘肃兴隆山国家级自然保护区林区顶级群落青杄为研究对象，利用甘肃兴隆山森林生态系统国家定位观测研究站2018-2020年度气象和不同径阶树木径向生长的数据，探究该区顶级群落青杄树干径向生长规律。结果表明，青杄树干径向生长与大气温湿度和热通量显著正相关，与土壤含水量和光合有效辐射呈负相关，与土壤温度不相关；青杄4-6月为快速生长期，7-10月进入缓慢生长期，11月至次年3月缓慢收缩；7:00-12:00为青杄树干收缩阶段，12:00-16:00，为膨胀阶段，16:00之后半径逐渐增加，在4:00达到最大值并持续至7:00，随后进入下一轮周期；降水条件下，不同胸径青杄较晴朗天气均表现出长周期，收缩期（SP）持续时间显著减少，膨胀恢复期（RP）时段加长，甚至表现出生长期（IP）周期持续的现象；青杄的生长受到上一年生长季末温度和降水的显著影响，这种影响主要是由树木体内养分积累状况造成的。  相似文献   

基于DEM数据分析川西云杉林与高山柏林空间分布特征——以石渠县为例          下载免费PDF全文

吴胜义    张方圆    王飞    林双福    刘强生   《西北林学院学报》2022,37(3):133-138

以2019年森林资源规划设计调查小班数据为基础，叠加数字高程模型,应用地理信息系统技术提取研究区海拔、坡度、坡向等地形因子。通过应用GIS空间分析,探究川西云杉林、高山柏林空间分布与地形因子的相关关系,分析其空间分布特征。结果表明:川西云杉、高山柏仅分布于石渠县西南部，金沙江及其一、二级支流两岸的高山峡谷地带，面积19 329.08 hm²。川西云杉林、高山柏林分布范围基本位于3 250~4 600 m；3 700~4 300 m海拔区间是集中分布区，川西云杉林占比92.19%，高山柏林占比80.78%。川西云杉林、高山柏林各坡度分布趋势相同，集中在26°～45°，占比分别为78.27%、78.68%。川西云杉林、高山柏林各坡向分布差异明显，川西云杉林多分布在阴坡、半阴坡，占比72.91%；高山柏林则多分布在阳坡和半阳坡，占比80.04%。  相似文献   

基于MaxEnt模型的油麦吊云杉西藏潜在适生区预测          下载免费PDF全文

舒骏生  彭玺  张晓晨  陈昕 《西北林学院学报》2023,38(1):66-72

为预测西藏自治区在实地调查中不可到达区域内油麦吊云杉的分布情况，通过MaxEnt生态位模型软件和ArcGIS软件预测其在西藏的潜在分布范围，用ROC曲线检测预测精度，用刀切法筛选主要环境变量，并通过主要环境变量的响应曲线分析适宜油麦吊云杉的生态环境条件。结果表明，建立的预测模型的A_UC为0.992,预测精度高；油麦吊云杉在西藏的分布范围主要位于藏东南区域，位于巴宜区、墨脱县的雅鲁藏布江沿线山地，波密县易贡藏布和帕隆藏布沿线山地，察隅县贡日嘎布曲、察隅河沿线山地，左贡县、芒康县南面的怒江、澜沧江沿线山地，与现地调查结果高度契合；年降水量、顶层土壤有机碳含量和年均温变化范围等条件对油麦吊云杉分布的影响最大。  相似文献