Regional heterogeneity and the effects of land use and climate on 20 lakes in the big woods region of Minnesota
Regional heterogeneity and the effects of land use and climate on 20 lakes in the big woods region of Minnesota
复制标题
DOI：
10.1007/s10933-010-9486-5
复制
发表时间：
2011-02
影响因子：
2.1
通讯作者：
C. Umbanhowar;P. Camill;J. A. Dorale
中科院分区：
文献类型：
--
作者：
C. Umbanhowar;P. Camill;J. A. Dorale
很少有研究评估景观、土地利用历史、气候和区域异质性对湖泊生态系统过程的相对重要性，尽管这些因素之间的相互作用对于控制湖泊动态可能很重要。我们使用了来自明尼苏达州南部草原森林边界气候敏感地区 20 个湖泊核心的 14 个沉积物测量数据，以 (1) 评估现代湖泊生产力（卡尔森营养状态指数 [TSI]）、现代土地利用、流域和湖泊形态测量之间的关系，以及 (2) 对比从“中世纪气候异常”（1000-1350 年）到“中世纪气候异常”（1350 年）气候转变的区域响应。 “小冰河时代”（1350-1800）到“现代”（~1980-1996 AD）。 TSI与现代沉降速率以及有机质（OM）、生物硅（BSi）和总磷（TP）的积累速率呈显着正相关。 TSI 与“现代”土地覆盖、流域或湖泊形态特征没有显着相关，但总有机氮 (N) 与流域面积的耕种百分比呈负相关，并与沉积物中大量有机质的 δ15N 呈负相关。过去 1000 年，区域、湖泊间的异质性很高，但小冰期 (LIA) 降温似乎导致 OM、BSi 和 TP 积累下降约 20%，而过去 150 年的变暖和文化富营养化则导致积累率增加 200-400%，碳酸盐增加 80%，C/N 减少 10%，虽小但显着。比率与更大的湖内一致 生产力。我们的结果表明，气候确实对湖泊生态系统有区域影响，但湖泊之间的变异性很高，反映了当地因素的重要性，并表明需要（1）对“区域”的含义进行更明确的定义，（2）关注变化的程度和方向，以及（3）根据多个湖泊和湖泊内的多个核心估算积累率。
Few studies have assessed the relative importance of landscape, land use history, climate, and regional heterogeneity on lake ecosystem processes, despite the likelihood that interactions among these factors must be important for controlling lake dynamics. We used 14 sediment measures from 20 lake cores in a climatically sensitive region of the prairie-forest border in southern Minnesota to (1) assess relationships between modern lake productivity (Carlson’s Trophic State Index [TSI]), modern land-use, catchment, and lake morphometry, and (2) contrast regional responses to climatic transitions from the ‘Medieval Climatic Anomaly’(1000–1350) to the ‘Little Ice Age’ (1350–1800) to ‘Modern’(~1980–1996 AD). TSI was significantly positively correlated with modern sedimentation rate, and accumulation rates of organic matter (OM), biogenic silica (BSi), and total phosphorus (TP). TSI was not significantly correlated with “modern” land cover, catchment, or lake morphometry characteristics, but total organic N(N) was negatively correlated with percent cultivation in the catchment area and negatively correlated with δ15N of bulk organic matter in sediment. Regional, among-lake heterogeneity was high over the past 1,000 years, but Little Ice Age (LIA) cooling appeared to result in an approximately 20% decline in OM, BSi and TP accumulation, while warming and cultural eutrophication of the past 150 years corresponded to a 200–400% increase in accumulation rates as well as an 80% increase in carbonates and a small but significant 10% drop in C/N ratios consistent with greater in-lake productivity. Our results indicate that climate does have regional effects on lake ecosystems but that among-lake variability is high, reflecting the importance of local factors and suggesting a need for (1) more explicit definition of what ‘regional’ means, (2) a focus on degree as well as direction of change, and (3) estimating accumulation rates based on multiple lakes and multiple cores within lakes.