Fowler Nicholas L, Petroelje Tyler R, Kautz Todd M, Svoboda Nathan J, Duquette Jared F, Kellner Kenneth F, Beyer Dean E, Belant Jerrold L
Global Wildlife Conservation Center College of Environmental Science and Forestry State University of New York Syracuse New York USA.
Alaska Department of Fish and Game, Kodiak Kodiak Alaska USA.
Ecol Evol. 2022 Feb 9;12(2):e8542. doi: 10.1002/ece3.8542. eCollection 2022 Feb.
The parallel niche release hypothesis (PNR) indicates that reduced competition with dominant competitors results in greater density and niche breadth of subordinate competitors and which may support an adaptive advantage.We assessed support for the PNR by evaluating relationships between variation in niche breadth and intra- and interspecific density (an index of competition) of wolves () coyotes (), and bobcats ().We estimated population density (wolf track surveys, coyote howl surveys, and bobcat hair snare surveys) and variability in space use (50% core autocorrelated kernel density home range estimators), temporal activity (hourly and overnight speed), and dietary (isotopic δC and δN) niche breadth of each species across three areas of varying wolf density in the Upper Peninsula of Michigan, USA, 2010-2019.Densities of wolves and coyotes were inversely related, and increased variability in space use, temporal activity, and dietary niche breadth of coyotes was associated with increased coyote density and decreased wolf density supporting the PNR. Variability in space use and temporal activity of wolves and dietary niche breadth of bobcats also increased with increased intraspecific density supporting the PNR.Through demonstrating decreased competition between wolves and coyotes and increased coyote niche breadth and density, our study provides multidimensional support for the PNR. Knowledge of the relationship between niche breadth and population density can inform our understanding of the role of competition in shaping the realized niche of species.
平行生态位释放假说（PNR）表明，与优势竞争者的竞争减少会导致从属竞争者的密度和生态位宽度增加，这可能支持一种适应性优势。我们通过评估狼（Canis lupus）、郊狼（Canis latrans）和山猫（Lynx rufus）的生态位宽度变化与种内和种间密度（竞争指数）之间的关系，来评估对PNR的支持。我们估计了美国密歇根州上半岛三个狼密度不同的区域中每个物种的种群密度（狼踪调查、郊狼嗥叫调查和山猫毛发陷阱调查）以及空间利用（50%核心自相关核密度家域估计器）、时间活动（每小时和夜间速度）和饮食（同位素δC和δN）生态位宽度的变异性，时间跨度为2010 - 2019年。狼和郊狼的密度呈负相关，郊狼空间利用、时间活动和饮食生态位宽度变异性的增加与郊狼密度增加和狼密度降低相关，支持了PNR。狼的空间利用和时间活动变异性以及山猫的饮食生态位宽度也随着种内密度的增加而增加，支持了PNR。通过证明狼和郊狼之间竞争的减少以及郊狼生态位宽度和密度的增加，我们的研究为PNR提供了多维度支持。了解生态位宽度与种群密度之间的关系可以增进我们对竞争在塑造物种实际生态位中的作用的理解。
