Granivory in Desert Ecosystems

Brown, James H.; Reichman, O. J.; Davidson, Diane W.

doi:10.1146/annurev.es.10.110179.001221

Cited by 461 publications

(341 citation statements)

References 68 publications

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“…1 Many factors can affect rodent population dynamics, including food availability, disease, and climatic variables, such as precipitation and temperature. [4][5][6][7][8][9][10][11][12] Seasonal fluctuations in the abundance of certain flea species also have been reported to be correlated with precipitation and temperature changes. [13][14][15][16][17] Additionally, the ability of fleas to transmit Y. pestis has been demonstrated to be temperature-dependent, with high temperatures (Ն 81.5ЊF, Ն 27.5ЊC) resulting in reduced rates of transmission.…”

Section: Introductionmentioning

confidence: 99%

Modeling relationships between climate and the frequency of human plague cases in the southwestern United States, 1960-1997.

Enscore¹,

Biggerstaff²,

Brown³

et al. 2002

The American Journal of Tropical Medicine and Hygiene

153

158

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Abstract. The relationships between climatic variables and the frequency of human plague cases were modeled by Poisson regression for two adjoining regions in northeastern Arizona and northwestern New Mexico. Model outputs closely agreed with the numbers of cases actually observed, suggesting that temporal variations in plague risk can be estimated by monitoring key climatic variables, most notably maximum daily summer temperature values and time-lagged (1 and 2 year) amounts of late winter (February-March) precipitation. Significant effects also were observed for time-lagged (1 year) summer precipitation in the Arizona model. Increased precipitation during specific periods resulted in increased numbers of expected cases in both regions, as did the number of days above certain lower thresholds for maximum daily summer temperatures (80ЊF in New Mexico and 85ЊF in Arizona). The number of days above certain high-threshold temperatures exerted a strongly negative influence on the numbers of expected cases in both the Arizona and New Mexico models (95ЊF and 90ЊF, respectively). The climatic variables found to be important in our models are those that would be expected to influence strongly the population dynamics of the rodent hosts and flea vectors of plague.

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Section: Introductionmentioning

confidence: 99%

Modeling relationships between climate and the frequency of human plague cases in the southwestern United States, 1960-1997.

Enscore¹,

Biggerstaff²,

Brown³

et al. 2002

The American Journal of Tropical Medicine and Hygiene

153

158

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“…Mature stands of desert shrubs may effectively prevent recruitment of their own offspring through superior competitive ability, so that favorable weather sequences must be coupled with some form of disturbance for natural recruitment to occur (Sheps 1973;Hunter 1989;Owens and Norton 1989;Mauchamp et al 1993). And the seeds of shrubs may be a primary source of food for at least one of several guilds of desert granivores, including ants, rodents, and birds, so that 'mast' years of exceptionally high seed production may be necessary for seeds to escape predation and enter the seed bank (Brown et al 1979;Kelly 1994;Herrera et al 1998). Shrub recruitment in deserts is therefore expected to be episodic as well as patchy in nature and not often observed.…”

Section: Introductionmentioning

confidence: 99%

Factors affecting seed germination and seedling establishment of a long-lived desert shrub (Coleogyne ramosissima: Rosaceae)

Meyer

Pendleton

2005

Plant Ecol

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Long-lived desert shrubs exhibit infrequent, episodic recruitment from seed. In spite of this long time scale, selection on life history attributes that affect seedling recruitment should be strong. We studied factors affecting germination phenology and seedling establishment for Coleogyne ramosissima, a dominant shrub species in the ecotone between warm and cold deserts in western North America. We also examined ecotypic differentiation in establishment strategy in response to selection regimes in two contrasting habitats. We followed patterns of dormancy loss, germination, emergence, and survival in reciprocal field experiments at warm winter Mojave Desert and cold winter Colorado Plateau study sites. Seed germination took place in late winter, under winter rain conditions at the warm desert site and under snow at the cold desert site. Distinctive germination phenologies for the two seed populations at contrasting field sites followed predictions based on laboratory germination experiments. There was no seed bank carryover across years. Seedling survival at the end of three growing seasons was remarkably high (mean survival 54%). Most seedling mortality was due to sprout predation by rodents early the first spring in unprotected caches. Emergence and establishment at each site were significantly higher for seeds from the local population, supporting the idea of ecotypic differentiation in establishment strategy. Establishment success was an order of magnitude greater overall at the Colorado Plateau site, which represents the leading edge of an upward elevational shift in distribution for this species under the current climatic regime. The Mojave Desert site is on the trailing edge of this shift, and recruitment there is apparently a much less frequent occurrence.

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“…In these studies, ants have been shown to to play a role in seed dispersal (Gorn et al 2000;Heithaus 1981), grain consumption (Brown et al 1979), decomposition (Haines 1978), defoliation (Cherrett 1968) and soil nutrient turnover (Wagner et al 1997;Nkem 2000;Risch et al 2005). Although some of these functions may also occur in higher latitude coniferous forests, for example, soil nutrient turnover (Frouz et al 2003), two specific ecological roles have been well established in ecosystems more typical of this province.…”

Section: List Of Figuresmentioning

confidence: 99%

“…In addition to pest control (Finnegan 1974;Torgersen and Mason 1987;Way and Khoo 1992), these include soil-nutrient turnover (Wagner et al 1997), seed dispersal (Heithaus 1981;Gorn et al 2000), grain consumption (Brown et al 1979), and decomposition of organic material (Haines 1978). Ants have also been found to be an important food source for birds and large omnivorous vertebrates such as black (Noyce et al 1997) and grizzly bears (Elgmork and Unander 1999;Swenson et al 1999).…”

Section: Introductionmentioning

confidence: 99%

The ant (Hymenoptera: Formicidae) communities of the central interior of British Columbia: Adaptations to a temperature-constrained environment.

Higgins¹

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Granivory in Desert Ecosystems

Cited by 461 publications

References 68 publications

Modeling relationships between climate and the frequency of human plague cases in the southwestern United States, 1960-1997.

Modeling relationships between climate and the frequency of human plague cases in the southwestern United States, 1960-1997.

Factors affecting seed germination and seedling establishment of a long-lived desert shrub (Coleogyne ramosissima: Rosaceae)

The ant (Hymenoptera: Formicidae) communities of the central interior of British Columbia: Adaptations to a temperature-constrained environment.

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