Hörnfeldt B, Löfgren O, Carlsson B -G
Department of Ecological Zoology, University of Umeå, S-901 87, Umeå, Sweden.
Oecologia. 1986 Mar;68(4):496-502. doi: 10.1007/BF00378761.
Population dynamics for voles (Cricetidae), Tengmalm's owl (Aegolius funereus (L.)), red fox (Vulpes vulpes (L.)) willow grouse (Lagopus lagopus (L.)), black grouse (Lyrurus tetrix (L.)), capercaillie (Tetrao urogallus L.), hazel hen (Tetrastes bonasia (L.)), mountain hare (Lepus timidus L.) and tularemia (Francisella tularensis (McCoy & Chapin)) and game bird recruitment were studied by index methods in northern Sweden. In addition contemporary temperature records and spruce (Picea abies (L.) Karst.) and pine (Pinus silvestris L.) cone crops (as indices for plant production) and the occurrence of forest damage, caused by voles eating bark, were studied.During 1970-80 two synchronous 4-year cycles were observed for voles, predators (Tengmalm's owl and red fox) and their alternative prey species (grouse and mountain hare). In grouse the change of numbers was correlated with that of recruitment. Autumn vole numbers peaked about a year before the other species and extensive forest damage occurred at winter peak densities of voles. These population fluctuations are consistent with a predator-prey model for their regulation. In short the model suggests that vole-food plant interactions trigger the cycle of voles, that voles generate the cycle of predators and that these in turn synchronize alternative prey populations to the others at vole declines.For voles, grouse and red fox the amplitude was higher in the first cycle compared to the second one whilst the opposite was true for the mountain hare. Although temperature and cone crops showed large interannual variations they still implied that herbivore food conditions were 'better' during the former cycle. Hence, the reduction of the amplitude of the vole cycle may be explained by inter-cyclic differences in plant food conditions, implying food shortage (as indicated by bark-eating) at different population levels. The similar decrease of grouse and red fox populations may also be explained by deteriorated food conditions and/or for the fox by an outbreak of sarcoptic mange (Sarcoptes scabiae var. vulpes). The increased amplitude of the mountain hare cycle was part of a long-term rise in numbers after a tularemia epidemic in 1967. This is interpreted as a recovery, probably towards the generally higher pre-epidemic population level.
在瑞典北部，通过指数方法研究了田鼠（仓鼠科）、长耳鸮（鬼鸮（林奈））、赤狐（赤狐（林奈））、柳雷鸟（柳雷鸟（林奈））、黑琴鸡（黑琴鸡（林奈））、松鸡（西方松鸡 林奈）、榛鸡（花尾榛鸡（林奈））、山地野兔（北极野兔（林奈））以及土拉菌病（土拉弗朗西斯菌（麦科伊和查平））和猎禽补充数量的种群动态。此外，还研究了当代温度记录、云杉（欧洲云杉（林奈）喀斯特）和松树（欧洲赤松 林奈）球果产量（作为植物产量指标）以及由田鼠啃食树皮造成的森林损害情况。在1970 - 1980年期间，观察到田鼠、捕食者（长耳鸮和赤狐）及其替代猎物物种（雷鸟和山地野兔）出现了两个同步的4年周期。在雷鸟中，数量变化与补充数量的变化相关。秋季田鼠数量在其他物种达到峰值大约一年前达到顶峰，并且在田鼠冬季密度峰值时发生了广泛的森林损害。这些种群波动与用于调节它们的捕食者 - 猎物模型一致。简而言之，该模型表明田鼠与食物植物的相互作用引发了田鼠的周期，田鼠产生了捕食者的周期，而这些捕食者又在田鼠数量下降时使替代猎物种群与其他种群同步。对于田鼠、雷鸟和赤狐，第一个周期的波动幅度比第二个周期更高，而山地野兔的情况则相反。尽管温度和球果产量表现出较大的年际变化，但它们仍然表明在前一个周期中食草动物的食物条件“更好”。因此，田鼠周期波动幅度的减小可能是由植物食物条件的周期间差异所解释的，这意味着在不同种群水平上存在食物短缺（如啃食树皮所示）。雷鸟和赤狐种群数量的类似下降也可能是由于食物条件恶化和 / 或对于狐狸来说是由于疥螨病（疥螨变种狐）的爆发。山地野兔周期波动幅度的增加是1967年土拉菌病流行后数量长期上升的一部分。这被解释为一种恢复，可能是朝着流行前普遍较高的种群水平恢复。
