DELAYED DENSITY-DEPENDENCE AS A DETERMINANT OF VOLE CYCLES
DELAYED DENSITY-DEPENDENCE AS A DETERMINANT OF VOLE CYCLES
复制标题
DOI：
10.2307/1941735
复制
发表时间：
1994-04-01
期刊：
影响因子：
4.8
通讯作者：
HORNFELDT, B
中科院分区：
文献类型：
--
作者：
HORNFELDT, B
1971-1988年，在瑞典北部乌梅阿附近一个季节性较强的环境中，用捕捉法监测了1971-1988年春季和秋季灰腹隐翅虫、红腹隐翅虫和黑线田鼠种群的基本同步波动。所有物种都是周期性的，它们表现出相当规则的(3-4年)波动，但幅度((Max)/n(Min))不同，每个物种的平均幅度几乎相等到200倍。这一结论得到了自相关和光谱分析的支持，并通过将时间序列数据拟合到相位遗忘周期的模型来支持。相反，数据不符合(具有固定周期和幅度的)相位记忆周期的模型。周期之间的过渡，即从低到高，其特征是在夏季和冬季，数字的变化率从低到高或明显较高。总体而言，夏季的变化速度从增长期到每个周期都在不断下降。此外，冬季的变化率也有类似的下降，尽管变化率(主要是红鳍金龟子和黑斑潜蝇)在周期的早期首先经常增加。在夏季和冬季，所有物种的变化率都表现出延迟的密度依赖关系，表现为夏季和冬季的变化分别与前两个秋季和春季的密度呈高度负相关。这些关于延迟密度依赖(DDD)的新发现支持了田鼠周期是由时间滞后机制产生的这一观点。对不同田鼠种群数量变化率的回归分析表明，种群数量的变化率除了与以前的密度有很强的依赖关系外，还受到当前种子供应(沙田鼠)和/或可能影响食物数量或质量的天气变量(温度和降雨量)的影响。
Largely synchronous population fluctuations of Clethrionomys glareolus, C. rufocanus, and Microtus agrestis were monitored by snap-trapping in spring and autumn in 1971-1988 in a strongly seasonal environment near UmeA, northern Sweden. All species were cyclic in the sense that they showed fairly regular (3-4 yr) fluctuations, but amplitudes ((max)/n(min)) varied, averaging almost-equal-to 200-fold in each species. This conclusion was supported by autocorrelation and spectral analysis, and by fitting time series data to a model for phase-forgetting cycles. By contrast, data did not conform to a model for phase-remembering cycles (with fixed period and amplitude).The transition between cycles, i.e., from the low to increase phase, was characterized by a distinct shift in rate of change in numbers from low to high or markedly higher values both in summer and winter. Generally, rate of change in summer declined continuously from the increase phase through each cycle. Moreover, there was a similar decrease of rate of change in winter, although rate of change (mainly in C. rufocanus and M. agrestis) first frequently increased early in the cycle. Rate of change was delayed density dependent in all species both in summer and winter, as revealed by high negative correlations with density in previous autumn and spring for summer and winter changes, respectively. These new findings of delayed density dependence (DDD) support the suggestion that vole cycles are generated by a time-lag mechanism. Possible mechanisms of the DDD are discussed.Regression analyses of rate of change in the different voles suggest that, besides the strong dependence on previous density, rate of change in numbers was also affected by current seed supply (in C glareolus) and/or weather variables (temperature and precipitation sums) that may have affected the quantity or quality of food.