对于许多物种来说,空间使用和饮食组成之间的关系是复杂的,个人采用不同的空间使用策略,如地域性,以促进资源获取。土狼(Canislatrans)表现出两种不同类型的空间使用;捍卫相互排斥的领土(居民)或游牧地穿越景观(瞬变)。居民土狼增加了对熟悉的食物资源的获取,从而改善了觅食机会,以补偿保卫领土的能量成本。相反,瞬变不保卫领土,能够将领土防御的能量成本转向广泛的运动,以寻找配偶和繁殖机会。这些空间使用的差异归因于不同的行为策略可能会影响觅食和最终的饮食组成,但是这些关系还没有得到很好的研究。我们通过将单个空间使用模式与稳定碳(δ13C)和氮(δ15N)同位素值的分析配对来评估饮食,从而研究了美国东南部居民和短暂的土狼的饮食组成。在2016-2017年期间,我们监测了41只土狼(26名居民,15瞬变)与美国东南部萨凡纳河地区的GPS无线电项圈一起使用。我们在土狼饮食中观察到冠层对δ13C值的影响和很少的人为食物,表明13C富集可能受到冠层覆盖率降低的影响大于人类食物的消耗。我们还观察到其他土地覆盖效应,如农业覆盖率和道路密度,在δ15N值以及土狼使用的缩小空间上,表明覆盖类型和本地化,居民般的空间使用会影响土狼的食肉程度。最后,尽管观察到潜在食物来源对其饮食的比例贡献存在差异,但常住土狼和短暂土狼的饮食和生态位空间没有差异。尽管我们的稳定同位素混合模型检测到常驻和短暂土狼饮食之间的差异,两者都主要依赖哺乳动物的猎物(52.8%,居民的SD=15.9,42.0%,瞬变的SD=15.6)。居民土狼消耗更多的野鸟(21.3%,SD=11.6vs13.7%,SD=8.8)和较少的水果(10.5%,SD=6.9vs21.3%,SD=10.7)和昆虫(7.2%,SD=4.7vs14.3%,SD=8.5)比瞬态。我们的发现表明,土狼种群落在杂食到食肉动物的连续摄食上,其中摄食策略的变异性受土地覆盖特征和空间使用行为的影响。
For many species, the relationship between space use and diet composition is complex, with individuals adopting varying space use strategies such as territoriality to facilitate resource acquisition.
Coyotes (Canis latrans) exhibit two disparate types of space use; defending mutually exclusive territories (residents) or moving nomadically across landscapes (transients). Resident
coyotes have increased access to familiar food resources, thus improved foraging opportunities to compensate for the energetic costs of defending territories. Conversely, transients do not defend territories and are able to redirect energetic costs of territorial defense towards extensive movements in search of mates and breeding opportunities. These differences in space use attributed to different behavioral strategies likely influence foraging and ultimately diet composition, but these relationships have not been well studied. We investigated diet composition of resident and transient
coyotes in the southeastern United States by pairing individual space use patterns with analysis of stable carbon (δ13C) and nitrogen (δ15N) isotope values to assess diet. During 2016-2017, we monitored 41
coyotes (26 residents, 15 transients) with GPS radio-collars along the Savannah River area in the southeastern United States. We observed a canopy effect on δ13C values and little anthropogenic food in coyote diets, suggesting 13C enrichment is likely more influenced by reduced canopy cover than consumption of human foods. We also observed other land cover effects, such as agricultural cover and road density, on δ15N values as well as reduced space used by coyotes, suggesting that cover types and localized, resident-like space use can influence the degree of carnivory in coyotes. Finally, diets and niche space did not differ between resident and transient coyotes despite differences observed in the proportional contribution of potential food sources to their diets. Although our stable isotope mixing models detected differences between the diets of resident and transient coyotes, both relied mostly on mammalian prey (52.8%, SD = 15.9 for residents, 42.0%, SD = 15.6 for transients). Resident
coyotes consumed more game birds (21.3%, SD = 11.6 vs 13.7%, SD = 8.8) and less fruit (10.5%, SD = 6.9 vs 21.3%, SD = 10.7) and insects (7.2%, SD = 4.7 vs 14.3%, SD = 8.5) than did transients. Our findings indicate that coyote populations fall on a feeding continuum of omnivory to carnivory in which variability in feeding strategies is influenced by land cover characteristics and space use behaviors.