Juniper Oil Yield, Terpenoid Concentration, and Antimicrobial Effects on Deer

Schwartz, Charles C.; Nagy, Julius G.; Regelin, Wayne L.

doi:10.2307/3808356

Cited by 70 publications

(35 citation statements)

References 10 publications

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“…Several studies have already demonstrated that monoterpenes can affect cervid food choice (mule deer: Longhurst et al 1968;Welch et al 1981;red deer, Cervus elaphus: Elliott and Loudon 1987;Duncan et al 1994), and in vitro experiments have shown that monoterpenes can be toxic to mammalian herbivores by inhibiting rumen microbial activity (Oh et al 1967;Schwartz et al 1980). Monoterpenes are volatile molecules and in addition to being toxic could serve as olfactive signals (Elliott and Loudon 1987) and influence food choice before browsing by deer.…”

Section: Plant Choice By Deer and Its Relation To Chemical Compositionmentioning

confidence: 95%

Defensive adaptations of Thuja plicata to ungulate browsing: a comparative study between mainland and island populations

et al. 2001

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Forests on the Haida Gwaii (HG) archipelago (British Columbia, Canada) evolved for about 10,000 years in the absence of large-mammal browsing. The introduction of black-tailed deer (Odocoileus hemionus sitkensis) from the mainland prior to 1901 provides an opportunity to evaluate changes in the adaptive defensive responses of plants to herbivory. We compared (1) food choice by deer and (2) chemical defence (terpene concentrations) between HG and mainland red cedars (Thuja plicata) using (1) nursery-grown seedlings never exposed to deer, (2) branches from trees that grew before the introduction of deer ("old trees") and (3) saplings exposed to deer herbivory on the mainland and on HG. We used the first two plant categories to test the hypothesis that plants that evolve under low herbivory levels have lower anti-herbivore defences. We used saplings to study the consequences of the dramatic increase in browsing on HG. During food experiments, deer preferred HG seedlings and old tree branches compared to those from the mainland. Total monoterpene concentrations were much higher than diterpene concentrations in all plant categories. Within plant categories, multivariate analysis showed that terpene profiles differed significantly between HG and mainland red cedars: HG seedlings and old trees had lower monoterpene levels. These results suggest that some monoterpenes may be determinants of deer food choice and that the defences of HG plants are less effective than those of mainland plants. The deer used branches from HG and mainland saplings indiscriminately. However, terpene profiles differed significantly between HG and mainland saplings, with multivariate analysis suggesting a higher defensive response in browsed HG saplings. Monoterpene profiles were different in lightly and heavily browsed saplings from HG, suggesting that under the current browsing regime, individuals with the greatest constitutive defences, or with greatest potential for induced defences, grow better and are selected on HG.

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Section: Plant Choice By Deer and Its Relation To Chemical Compositionmentioning

confidence: 95%

Defensive adaptations of Thuja plicata to ungulate browsing: a comparative study between mainland and island populations

et al. 2001

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“…Over 60 % of the total monoterpene constituents for western red-cedar are comprised of a-, b-thujone, which is an oxygenated terpenoid compound not found in either Douglas-fir or western hemlock. These oxygenated monoterpenes have been shown by Schwartz et al (1980) to inhibit microbial fermentation within ungulate rumen and, thus, act as a deterrent to ungulate browse (Vourc'h et al 2002). This link was evident in a field study conducted by Burney and Jacobs (2011) in which western red-cedar seedlings with higher concentrations of a-, b-thujone had a significantly lower likelihood of ungulate browse.…”

Section: Discussionmentioning

confidence: 98%

Terpene production and growth of three Pacific Northwest conifers in response to simulated browse and nutrient availability

Burney

Jacobs

2012

Trees

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Natural variation in ungulate browsing behavior interferes with the understanding of plant morphological and biochemical responses to herbivory. To investigate mechanisms for recovery from herbivory, we examined growth patterns and biosynthesis of terpenoids under simulated browse (three clipping intensities) and supplemental mineral nutrition (four levels of controlled-release fertilization) for Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco], western hemlock (Tsuga heterophylla Raf. Sarg.), and western red-cedar (Thuja plicata Donn ex D. Don) seedlings on a reforestation site in Northwestern Oregon, USA, that was fenced to exclude ungulates. Higher clipping intensities increased relative height growth (at cost of diameter growth) for all the species. Only western red-cedar showed a decline in monoterpene concentrations with increasing clipping severity, suggesting prioritization in biosynthesis of terpenoids for this species. Douglas-fir and western hemlock responded to fertilization mostly through increased growth. Western red-cedar growth responses to fertilization were less pronounced, but monoterpene concentrations were 2-3 times higher compared to non-fertilized trees. Douglas-fir and western hemlock browse recovery and responses to fertilization consisted primarily of increased growth, while western red-cedar balanced growth promotion with production of chemical defense compounds. Our data suggests the evolution of speciesdependent resource allocation strategies in response to both browse and soil nutrient availability.

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“…Past research has identified the oxygenated monoterpenes, a-and b-thujone, to quickly degrade in the ruminal milieu and form the toxic compounds iso-3-thujanol, neo-3-thujanol, carvomethone, and carvomenthol (Chizzola et al, 2004). Oh et al (1967) and Schwartz et al (1980) found that oxygenated monoterpenes (not including a-and b-thujone) strongly inhibited microbial fermentation within ungulate rumen, whereas hydrocarbon monoterpenes (a-pinene, b-pinene, b-myrcrene, a-phellendrene, sabinene, limonene, and D-carene) were found to actually promote fermentation (Oh et al, 1967;Schwartz et al, 1980). Results from this study suggest that increased western redcedar monoterpene production from fertilization results in higher concentration levels of a-and b-thujone and thus provides seedlings with a stronger deterrent mechanism against ungulate browse.…”

Section: Discussionmentioning

confidence: 98%

Ungulate herbivory of regenerating conifers in relation to foliar nutrition and terpenoid production

Burney

Jacobs

2011

Forest Ecology and Management

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Juniper Oil Yield, Terpenoid Concentration, and Antimicrobial Effects on Deer

Cited by 70 publications

References 10 publications

Defensive adaptations of Thuja plicata to ungulate browsing: a comparative study between mainland and island populations

Defensive adaptations of Thuja plicata to ungulate browsing: a comparative study between mainland and island populations

Terpene production and growth of three Pacific Northwest conifers in response to simulated browse and nutrient availability

Ungulate herbivory of regenerating conifers in relation to foliar nutrition and terpenoid production

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