Reading C J
Institute of Terrestrial Ecology, Furzebrook Research Station, Wareham, Dorset, BH20 5AS, UK e-mail:
Oecologia. 1998 Dec;117(4):469-475. doi: 10.1007/s004420050682.
A 19-year study of a common toad population in south Dorset, UK, was carried out between 1980 and 1998. The daily arrival of sexually mature male and female toads at a breeding pond was recorded each year. The timing of the main arrival of toads at the breeding pond was highly correlated with the mean daily temperatures over the 40 days immediately preceding the main arrival. When the temperatures were higher than average, breeding occurred significantly earlier in the year than if they were either average or lower than average. During the study, the toad breeding seasons were early (2-13 February) in 5 years (1989, 1990, 1993, 1995, 1998), late (16-23 March) in 2 years (1986, 1996) and average (25 February-8 March) during the remaining 12 years. Evidence was found suggesting that common toads have a daylength threshold of about 9 h, below which the migration to the breeding pond does not occur. Evidence was also found indicating that common toads in southern England have a threshold temperature for activity of about 6°C and that the onset of breeding activity is highly correlated with the number of days during the 40 days prior to the main arrival at the breeding pond that were at or above this temperature. Predicting the start of the main breeding migration to a pond in any year may be possible by comparing the pattern of the 40-day running mean daily temperatures from 21 December the preceding year with those from previous years when the start of breeding activity is known. Although all five of the earliest recorded toad breeding years occurred during the last 10 years, and were associated with the occurrence of particularly mild winters, a significant trend towards earlier breeding in recent years compared with previous years was not found.
1980年至1998年间，在英国多塞特郡南部对普通蟾蜍种群进行了一项为期19年的研究。每年记录性成熟的雄性和雌性蟾蜍每天抵达繁殖池塘的情况。蟾蜍主要抵达繁殖池塘的时间与主要抵达前40天的平均日气温高度相关。当气温高于平均水平时，当年的繁殖明显早于气温为平均水平或低于平均水平时。在研究期间，蟾蜍繁殖季节在5年（1989年、1990年、1993年、1995年、1998年）为早期（2月2日至13日），在2年（1986年、1996年）为晚期（3月16日至23日），其余12年为平均水平（2月25日至3月8日）。有证据表明普通蟾蜍有一个约9小时的日照长度阈值，低于这个阈值就不会向繁殖池塘迁移。还有证据表明，英格兰南部的普通蟾蜍活动的阈值温度约为6°C，繁殖活动的开始与主要抵达繁殖池塘前40天内达到或高于该温度的天数高度相关。通过比较前一年12月21日起40天的滑动平均日气温模式与已知繁殖活动开始时间的前几年的模式，有可能预测任何一年向池塘的主要繁殖迁移的开始。尽管最早记录的五个蟾蜍繁殖年份都发生在过去10年中，并且与特别温和的冬季有关，但未发现近年来与前几年相比有明显的提前繁殖趋势。
