Productivity and Flowering of Winter Ephemerals in Relation to Sonoran Desert Shrubs

Halvorson, W.L.; Patten, Duncan T.

doi:10.2307/2424164

Cited by 81 publications

(37 citation statements)

References 19 publications

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“…The water retention properties of the soil, rainfall (Beatley, 1974), and temperature (Halvorson & Pattern, 1975) are all factors that may affect the phenology of plants in arid tropical regions; plants of these regions are usually dependent on irregular rainfall (Friedel et al, 1993). Whatever the environmental condition triggering a plant species to flower, a floral homologue that shares the same pollinators may benefit from being triggered to flower by an opposite mechanism.…”

Section: Competition Reduction Hypothesismentioning

confidence: 99%

The reproductive phenology of three sympatric species of columnar cacti on Curaçao

Petit

2001

Journal of Arid Environments

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Section: Competition Reduction Hypothesismentioning

confidence: 99%

The reproductive phenology of three sympatric species of columnar cacti on Curaçao

Petit

2001

Journal of Arid Environments

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“…We observed that some green twigs and annual litter was left in front of some gerbil and rabbit burrows, even blocking the burrows in some cases. The rapid growth of desert summer annuals represents an important pulse in soil nutrient supply (Mulroy and Rundel 1977;Parker et al 1984), and plays an important role in desert productivity (Halvorson and Patten 1975). Hence, summer annuals provide some microbes and animals with high-quality food in desert ecosystems.…”

Section: Discussionmentioning

confidence: 99%

“…Most studies of desert annuals were limited to the Chihuahuan Desert (Gutierrez and Whitford 1987;Guo and Brown 1997;Fernández and Reynolds 2000), Mojave Desert (Beatley 1974;Brooks 2000;DeFalco et al 2001), Sonoran Desert (Halvorson and Patten 1975;Werk et al 1983;Forseth et al 1984;Adondakis and Venable 2004), and Negev Desert in Israel (Gutterman 2000), where winter rainfall plays an important role in ephemeral/annual growth, and most of the annuals are spring or winter plants. Moreover, few studies have focused on the role of desert annuals (including both spring/winter annuals and summer annuals) in nutrient conservation (Parker et al 1984), though annuals play a vital role in soil rehabilitation and production in desert ecosystems due to stabilization of dune surface, prevention of wind erosion, and stability maintenance of desert ecosystems (Wang et al 2003;Li et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Role of desert annuals in nutrient flow in arid area of Northwestern China: a nutrient reservoir and provider

2008

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Previous studies have tested the ''vernal dam'' hypothesis of spring ephemeral herbs in hardwood forests. The desert annual is a component of the desert ecosystem that takes advantage of water resources and temperature conditions during the rainy season to rapidly complete its life cycle within several months. To understand the role desert annual/ephemeral plants play in nutrient flow, we studied vegetation cover, nitrogen content and litter production of annual plants and litter decomposition rate in plant communities dominated by four shrubs (Haloxlon ammodendron, Hedysarum scoparium, Calligonum mongolicum, and Nitraria tangutorum) and two dominant annuals (Agriophyllum squarrosum and Halogeton arachnoideus Moq) in Minqin, northwestern China. Results indicate that over half of the total vegetation cover was provided by annuals. Annuals also took up a large amount of nitrogen (0.46-3.78 g N m -2 ) along the oasis-desert ecotone. Litter production and nutrient content were higher in areas dominated by annual plants than in areas dominated by shrubs. Furthermore, the litter decomposition rate of the annuals was higher than that of the shrubs, except for the shrub H. ammodendron, although almost all of the litter's carbon (C) and nitrogen (N) remained after 6 months of decomposition. Without the annuals, more nutrients and rainwater might be lost through leaching or dust transfer caused by the wind erosion. In addition, green twigs of the annuals are the food for some animals, we found some green twigs and litter from annuals left in front of gerbil and rabbit burrows, sometimes even blocking these burrows. Thus, desert summer annuals, like nutrient reservoirs and providers, take up nutrients during the rainy season, providing some animals and microbes with food, and finally release these nutrients after death.

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“…Studies in semiarid environments have demonstrated that germination of annual forbs and grasses can begin at precipitation levels ranging from 10 to 25 mm. [49][50][51] This appearance of green vegetation sparked by winter rains is often followed by a subsequent senescent period. 52 It is during this senescent period that deep-rooted woody vegetation will green-up, with perennial grasses following after the onset of summer rains (Fig.…”

Section: Ndvimentioning

confidence: 99%

Development of an integrated multiplatform approach for assessing brush management conservation efforts in semiarid rangelands

Collins

Kautz

Tiller

et al. 2015

J. Appl. Remote Sens

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Abstract. Millions of dollars have been spent on brush management, or removal of unwanted woody vegetation, as a conservation practice to control the presence of woody species. Land managers need an inexpensive means of monitoring the effects of brush management conservation methods for decreasing degradation in rangeland systems. In this study, free, publically available, high-resolution (1 m) imagery from the National Agricultural Imagery Program (NAIP) and moderate-resolution (30 m) Landsat-5 Thematic Mapper (TM) imagery were combined to produce a large-scale technique for mapping woody cover. High-resolution imagerybased estimates of woody cover were found to be reasonable (RMSE ¼ 3.8%, MAE ¼ 2.9%) surrogates for ground-based woody cover. An equation for TM-derived woody cover was developed. TM scenes of woody cover (TM WC ) were produced and validated using NAIP and ground-based data. Results showed that the developed relation produced viable (RMSE ¼ 8.5%, MAE ¼ 6.4%) maps of woody cover that could be used to successfully track the occurrence of brush removal, as well as monitor the presence or lack of subsequent reemergence. This work provides land managers with an operational means of determining where to allocate resources to implement brush management, as well as a cost-effective method of monitoring the effects of their efforts.

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Productivity and Flowering of Winter Ephemerals in Relation to Sonoran Desert Shrubs

Cited by 81 publications

References 19 publications

The reproductive phenology of three sympatric species of columnar cacti on Curaçao

The reproductive phenology of three sympatric species of columnar cacti on Curaçao

Role of desert annuals in nutrient flow in arid area of Northwestern China: a nutrient reservoir and provider

Development of an integrated multiplatform approach for assessing brush management conservation efforts in semiarid rangelands

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