Effects of high fire frequency in creosote bush scrub vegetation of the Mojave Desert

2012 ◽  
Vol 21 (1) ◽  
pp. 61 ◽  
Author(s):  
Matthew L. Brooks
Keyword(s):  
Mojave Desert ◽  
Plant Invasions ◽  
Fire Frequency ◽  
Creosote Bush ◽  
Community Characteristics ◽  
Short Term ◽  
Desert Ecosystems ◽  
Perennial Plants ◽  
Bromus Rubens ◽  
Creosote Bush Scrub

Plant invasions can increase fire frequency in desert ecosystems where fires were historically infrequent. Although there are many resource management concerns associated with high frequency fire in deserts, fundamental effects on plant community characteristics remain largely unstudied. Here I describe the effects of fire frequency on creosote bush scrub vegetation in the Mojave Desert, USA. Biomass of the invasive annual grass Bromus rubens L. increased following fire, but did not increase further with additional fires. In contrast, density, cover and species richness of native perennial plants each decreased following fire and continued to decrease with subsequent fires, although not as dramatically as after the initial fire. Responses were similar 5 and 14 years post-fire, except that cover of Hymenoclea salsola Torr. & A. Gray and Achnatherum speciosa Trin. & Rupr. both increased in areas burnt once. These results suggest that control of B. rubens may be equally warranted after one, two or three fires, but revegetation of native perennial plants is most warranted following multiple fires. These results are valid within the scope of this study, which is defined as relatively short term vegetation responses (≤14 years) to short fire return intervals (6.3 and 7.3 years for the two and three fire frequency levels) within creosote bush scrub of the Mojave Desert.

Relationships of Native Desert Plants with Red Brome (Bromus rubens): Toward Identifying Invasion-Reducing Species

2011 ◽  
Vol 4 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Scott R. Abella ◽  
Donovan J. Craig ◽  
Lindsay P. Chiquoine ◽  
Kathryn A. Prengaman ◽  
Sarah M. Schmid ◽  
...  
Keyword(s):  
Mojave Desert ◽  
Native Species ◽  
Strongly Correlated ◽  
Annual Grass ◽  
Desert Ecosystems ◽  
Red Brome ◽  
Bromus Rubens ◽  
Competitive Abilities ◽  
Practical Implications

AbstractThe interactions between native and exotic species occur on a continuum from facilitative to competitive. A growing thrust in invasive species science is differentiating where particular native species occur along this continuum, with practical implications for identifying species that might reduce the invasibility of ecosystems. We used a greenhouse experiment to develop a competitive hierarchy of 27 native species with red brome, an invasive annual grass in the arid lands of the southwestern United States, and a field study to assess in situ responses of brome to native perennial species in the Mojave Desert. Native species most competitive with brome in the competition experiment included the annuals Esteve's pincushion and western fiddleneck and the perennials eastern Mojave buckwheat, sweetbush, and brittlebush, which reduced brome biomass to 49 to 70% of its grown-alone amount. There was no clear difference in competitive abilities with brome between annual and perennial natives, and competiveness was not strongly correlated (r = 0.15) with the biomass of the native species. In the field, sweetbush and brittlebush supported among the least cover of brome, suggesting congruence of the strong early competitive abilities of these species with in situ patterns of brome distribution. At the other extreme, brome attained its highest average cover (19%) below littleleaf ratany, significantly greater than all but 3 of the 16 species evaluated. Cover by brome was only weakly related (r = 0.19) to the area of the perennial canopy, suggesting that factors other than the sizes of perennial plants were linked to differences in brome cover among species. Results suggest that (1) interactions with brome differ substantially among native species, (2) these interactions are not as closely linked to biomass production as in more temperate regions, and (3) there is potential for identifying native species that can reduce invasion of desert ecosystems.

A new species of Brethesiella (Hymenoptera: Encyrtidae) from California, USA, a parasitoid of Steatococcus tabernicolus (Hemiptera: Margarodidae)

Zootaxa ◽  
2006 ◽  
Vol 1167 (1) ◽  
pp. 1 ◽  
Author(s):  
VLADIMIR A. TRJAPITZIN ◽  
SERGUEI V. TRIAPITSYN
Keyword(s):  
New Species ◽  
Mojave Desert ◽  
New World ◽  
Larrea Tridentata ◽  
Creosote Bush ◽  
Type Series ◽  
A New Species

A new species of the encyrtid wasp genus Brethesiella Porter, 1920 is described from the Mojave Desert in California, USA. The type series of B. mojave sp. n. was reared from the margarodid scale Steatococcus tabernicolus Ferris on creosote bush, Larrea tridentata. The genus Aztecencyrtus Timberlake, 1926 is synonymized under Brethesiella and its two described species are transferred to the latter as B. flava (Timberlake, 1926) comb. n. and B. iceryae (Howard, 1892) comb. n. A brief review of the encyrtid parasitoids of Margarodidae, a diagnosis of Brethesiella, and an annotated key to its six described species with known females in the New World are provided.

The short-term effects of an extensive and high-intensity fire on vertebrates in the tropical savannas of the central Kimberley, northern Australia

2008 ◽  
Vol 35 (1) ◽  
pp. 33 ◽  
Author(s):  
Sarah Legge ◽  
Stephen Murphy ◽  
Joanne Heathcote ◽  
Emma Flaxman ◽  
John Augusteyn ◽  
...  
Keyword(s):  
Species Richness ◽  
High Intensity ◽  
Fire Frequency ◽  
Northern Australia ◽  
Tropical Savannas ◽  
Short Term ◽  
Large Herbivores ◽  
Species Richness And Abundance ◽  
Species Specific ◽  
In Fire

We report the effects of an extensive (>7000 km2), high-intensity late-dry-season fire in the central Kimberley, Western Australia, on the species richness and abundance of mammals, reptiles and birds. Five weeks after the fire we surveyed 12 sites (six burnt, six unburnt); each pair of sites was closely matched for soil type and vegetation. The species richness and abundance of mammals and reptiles was greater at unburnt sites, especially for mammals (with a 4-fold difference in abundance between burnt and unburnt sites). There was an indication that reptiles immigrated into unburnt patches, but mammals did not. There were also species-specific responses to the fire: Rattus tunneyi and Pseudomys nanus were much more abundant in unburnt sites, whereas Pseudomys delicatulus was caught in equal numbers at burnt and unburnt sites. Diurnal reptiles were more abundant at unburnt sites, but nocturnal reptiles were equally common at burnt and unburnt sites. Avian species richness and overall abundance was similar between burnt and unburnt patches, although a few species showed preferences for one state or the other. The overall high trapping success for mammals (18% across all sites; 28% in unburnt patches) contrasts with the well documented mammal collapse in parts of northern Australia and seems paradoxical given that our study area has experienced the same increase in fire frequency and extent that is often blamed for species collapse. However, our study area has fewer pressures from other sources, including grazing by large herbivores, suggesting that the effects of these pressures, and their interaction with fire, may have been underestimated in previous studies.

Short-term effects of experimental fires on a Mojave Desert seed bank

2010 ◽  
Vol 74 (10) ◽  
pp. 1302-1308 ◽  
Author(s):  
Todd C. Esque ◽  
James A. Young ◽  
C. Richard Tracy
Keyword(s):  
Seed Bank ◽  
Mojave Desert ◽  
Short Term ◽  
Short Term Effects

Short-term recolonization of stones in a tropical island stream

2002 ◽  
Vol 53 (6) ◽  
pp. 993 ◽  
Author(s):  
Luz Boyero ◽  
Jose Luis DeLope
Keyword(s):  
Significant Variation ◽  
National Park ◽  
Taxonomic Composition ◽  
Total Density ◽  
Community Characteristics ◽  
Tropical Stream ◽  
Short Term ◽  
Taxa Richness ◽  
Abiotic Variables ◽  
Community Evenness

The recolonization of stones by macroinvertebrates in streams can occur at very small temporal scales, an often-neglected factor in recolonization studies. In a tropical stream in Coiba National Park, Panama, 36 stones were washed and brushed and each one was subjected to four different periods of exposure in a riffle (1, 3, 9, 27 h). Ephemeroptera, together with Diptera, Trichoptera, Coleoptera, Lepidoptera and Hydracarina, were the main recolonizers. Total density of individuals, and density and relative abundance of the most common taxon (Baetidae : Ephemeroptera), showed significant variation over the four recolonization periods, partially explained by some abiotic variables (water depth, current velocity and stone shape). Taxa richness, community evenness and taxonomic composition did not vary significantly over the four periods. The recolonization of stones in the tropical stream began immediately after the disturbance, although only some community characteristics varied significantly over the first hours.

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