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首页> 外文期刊>Journal of Paleolimnology >Regional heterogeneity and the effects of land use and climate on 20 lakes in the big woods region of Minnesota
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Regional heterogeneity and the effects of land use and climate on 20 lakes in the big woods region of Minnesota

机译：明尼苏达州大森林地区的区域异质性以及土地利用和气候对20个湖泊的影响

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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.
机译：很少有研究评估景观，土地使用历史，气候和区域异质性在湖泊生态系统过程中的相对重要性，尽管这些因素之间的相互作用可能对于控制湖泊动态至关重要。我们使用了明尼苏达州南部草原-森林边界气候敏感地区20个湖心的14种沉积物测量值，以（1）评估现代湖生产力（卡尔森营养状态指数[TSI]），现代土地利用，集水区， （2）对比了从“中世纪气候异常”（1000-1350）到“小冰河世纪”（1350-1800）到“现代”（〜1980-1996 AD）的气候转变的区域响应。 TSI与现代沉积速率，有机质（OM），生物硅（BSi）和总磷（TP）的累积速率显着正相关。 TSI与“现代”土地覆盖，流域或湖泊形态特征无显着相关性，但总有机N（N）与流域面积的种植率呈负相关，与δ 15 N呈负相关沉积物中大量有机物的分布。在过去的1000年中，区域之间的湖间非均质性很高，但是小冰河时代（LIA）的降温似乎导致OM，BSi和TP积累下降了约20％，而过去150年的变暖和文化富营养化相应到200-400％的积累率增加了，碳酸盐的增加了80％，C / N比又小而显着地下降了10％，这与更高的湖内生产率相一致。我们的结果表明，气候确实对湖泊生态系统有区域性影响，但湖间变化很大，反映了当地因素的重要性，并表明需要（1）更明确地定义“区域性”的含义，（2）关注（3）基于多个湖泊和多个湖泊内的多个核心来估算累积速率。

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