Geographic patterns of simulated establishment of two <i>Bouteloua</i> species: implications for distributions of dominants and ecotones

Minnick, Tamera J.; Coffin, Debra P.

doi:10.2307/3237063

Cited by 45 publications

(41 citation statements)

References 48 publications

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“…These results are supported by simulation analyses showing that recruitment decreases geographically from the Shortgrass Steppe to the Chihuahuan Desert, but remains .0 at this biome transition zone (Minnick and Coffin 1999). However, B. eriopoda may be a relic based on current land management practices that promote livestock grazing throughout the region on public and private land, except in protected areas such as the Sevilleta National Wildlife Refuge.…”

Section: Patterns In Dominance and Trends In Cover Through Timementioning

confidence: 65%

Long‐term experimental loss of foundation species: consequences for dynamics at ecotones across heterogeneous landscapes

Peters

Jin

2012

Ecosphere

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Abstract. Biome transition zones where species co-exist near their geographic limits are expected to be among the most responsive to changes in climate that result in mortality of foundation species. Long-term (.13 years) patterns in dominance and cover of functional types were examined following the annual experimental removal of one of three foundation species at an arid-semiarid biome transition zone. Objectives were to identify key processes influencing these patterns, and to predict future landscape-scale dynamics following mortality of different foundation species. Aboveground biomass of dominant species was removed from 3 3 4 m plots. Cover by species on control and removal plots was estimated annually in communities with a single dominant species, and in ecotonal communities with two dominant species across two types of ecotones (semiarid grassland-arid grassland, arid grassland-arid shrubland).For most species and functional types, trends in cover through time were related to the remaining species assemblages rather than to variable climatic conditions. In ecotonal communities, resident co-dominant species increased to dominance following the loss of a foundation species with little change in community composition. In mono-dominated communities, dominant species loss resulted in a shift to species that are currently sub-dominants of the same functional type as the species that was removed. Subdominant perennial grass and shrub species increased rapidly following removals in most grassland locations. Annuals and perennial forbs had variable cover values through time that were not clearly related to pulses in precipitation and were not synchronized across locations. The most common response regardless of the identity of the foundation species removed or the community type was an increase in cover by subdominant grasses and by the arid grass species (Bouteloua eriopoda). The rate of increase by B. eriopoda depended on initial cover, and resulted from both vegetative growth and seedling recruitment from other locations. Seed dispersal and seedling recruitment from other locations were not found for the semiarid grass, Bouteloua gracilis or the arid shrub, Larrea tridentata. Because B. eriopoda is more susceptible to shrub invasion, drought, and livestock grazing than the other two foundation species, widespread loss of either of the other species and subsequent increase in B. eriopoda is expected to result in an increase in landscapescale vulnerability to these environmental drivers. The extent and magnitude of this change in vulnerability will depend on the ability of B. eriopoda to respond based on the micro-environmental conditions of the site regardless of which species (B. gracilis, L. tridentata) is lost.

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Section: Patterns In Dominance and Trends In Cover Through Timementioning

confidence: 65%

Long‐term experimental loss of foundation species: consequences for dynamics at ecotones across heterogeneous landscapes

Peters

Jin

2012

Ecosphere

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“…This can result from increases in seed number to CO 2 (Jablonski et al 2002), or from the more indirect effects of CO 2 on the seedbed environment (Edwards et al 2001), most importantly soil water content, light, and temperature, all of which can effect germination, emergence, and seedling survival (Wester 1995, Minnick andCoffin 1999). However, the significance of seedling recruitment responses to CO 2 is community dependent, as plant communities differ in the occurrence and importance of reproductive vs. vegetative recruitment.…”

Section: Introductionmentioning

confidence: 99%

CO₂ENHANCES PRODUCTIVITY, ALTERS SPECIES COMPOSITION, AND REDUCES DIGESTIBILITY OF SHORTGRASS STEPPE VEGETATION

Morgan¹,

Mosier

Milchunas

et al. 2004

Ecological Applications

158

176

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Abstract. The impact of increasing atmospheric CO 2 concentrations has been studied in a number of field experiments, but little information exists on the response of semiarid rangelands to CO 2 , or on the consequences for forage quality. This study was initiated to study the CO 2 response of the shortgrass steppe, an important semiarid grassland on the western edge of the North American Great Plains, used extensively for livestock grazing. The experiment was conducted for five years on native vegetation at the USDA-ARS Central Plains Experimental Range in northeastern Colorado, USA. Three perennial grasses dominate the study site, Bouteloua gracilis, a C 4 grass, and two C 3 grasses, Pascopyrum smithii and Stipa comata. The three species comprise 88% of the aboveground phytomass. To evaluate responses to rising atmospheric CO 2 , we utilized six open-top chambers, three with ambient air and three with air CO 2 enriched to 720 mol/mol, as well as three unchambered controls. We found that elevated CO 2 enhanced production of the shortgrass steppe throughout the study, with 41% greater aboveground phytomass harvested annually in elevated compared to ambient plots. The CO 2 -induced production response was driven by a single species, S. comata, and was due in part to greater seedling recruitment. The result was species movement toward a composition more typical of the mixed-grass prairie. Growth under elevated CO 2 reduced the digestibility of all three dominant grass species. Digestibility was also lowest in the only species to exhibit a CO 2 -induced production enhancement, S. comata. The results suggest that rising atmospheric CO 2 may enhance production of lower quality forage and a species composition shift toward a greater C 3 component.

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“…As a result of this assessment, we conducted a more extensive survey of the fungi associated with B. gracilis roots. B. gracilis is one of the most dominant perennial grasses in North America, in part, because it is highly resistant to drought (see the PLANTS database at http://plants.usda.gov) (12,47). Our hypothesis is that the wide distribution of B. gracilis may be related to its relationship with fungal endophytes.…”

mentioning

confidence: 99%

Novel Root Fungal Consortium Associated with a Dominant Desert Grass

Porras-Alfaro

Herrera

Sinsabaugh

et al. 2008

Appl Environ Microbiol

197

149

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The broad distribution and high colonization rates of plant roots by a variety of endophytic fungi suggest that these symbionts have an important role in the function of ecosystems. Semiarid and arid lands cover more than one-third of the terrestrial ecosystems on Earth. However, a limited number of studies have been conducted to characterize root-associated fungal communities in semiarid grasslands. We conducted a study of the fungal community associated with the roots of a dominant grass, Bouteloua gracilis, at the Sevilleta National Wildlife Refuge in New Mexico. Internal transcribed spacer ribosomal DNA sequences from roots collected in May 2005, October 2005, and January 2006 were amplified using fungal-specific primers, and a total of 630 sequences were obtained, 69% of which were novel (less than 97% similarity with respect to sequences in the NCBI database). B. gracilis roots were colonized by at least 10 different orders, including endophytic, coprophilous, mycorrhizal, saprophytic, and plant pathogenic fungi. A total of 51 operational taxonomic units (OTUs) were found, and diversity estimators did not show saturation. Despite the high diversity found within B. gracilis roots, the root-associated fungal community is dominated by a novel group of dark septate fungi (DSF) within the order Pleosporales. Microscopic analysis confirmed that B. gracilis roots are highly colonized by DSF. Other common orders colonizing the roots included Sordariales, Xylariales, and Agaricales. By contributing to drought tolerance and nutrient acquisition, DSF may be integral to the function of arid ecosystems.Symbiotic associations of fungi and plants are ancient and phylogenetically diverse (4,9,11,42,43,60,64,69). Some of these fungi, notably mycorrhizal fungi, have received extensive study, but accumulating evidence indicates that many of the fungi associated with plant roots are dark septate fungi (DSF). These fungi are usually described as endophytes, whose functions have only recently been studied (43,44,76). DSF comprise a taxonomically diverse group (34, 37) characterized by melanized septate hyphae. Endophytes with hyaline hyphae are also common (e.g., see references 48, 53, and 76), but are less well characterized, because they are more difficult to detect in microscopic analysis and are sometimes considered contaminants in mycorrhizal fungal studies. Growing evidence showing the broad distribution and high root colonization rates of DSF in different ecosystems suggests that their functional importance may rival that of arbuscular mycorrhizal fungi (AMF) (1, 43), particularly for plants growing in stressed environments, such as alpine habitats and arid grasslands (8, 45a, 54, 56, 75). In these habitats, endophytic DSF and other rootassociated fungi allow some plants to increase their resistance to drought and heat and facilitate the acquisition of nutrients (23, 43, 45a, 50, 57, 76, 81).Desert environments are one of the most challenging ecosystems for plants and microorganisms (18,51,87). Biological activity, dive...

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Geographic patterns of simulated establishment of two Bouteloua species: implications for distributions of dominants and ecotones

Cited by 45 publications

References 48 publications

Long‐term experimental loss of foundation species: consequences for dynamics at ecotones across heterogeneous landscapes

Long‐term experimental loss of foundation species: consequences for dynamics at ecotones across heterogeneous landscapes

CO₂ENHANCES PRODUCTIVITY, ALTERS SPECIES COMPOSITION, AND REDUCES DIGESTIBILITY OF SHORTGRASS STEPPE VEGETATION

Novel Root Fungal Consortium Associated with a Dominant Desert Grass

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Geographic patterns of simulated establishment of two Bouteloua species: implications for distributions of dominants and ecotones

Cited by 45 publications

References 48 publications

Long‐term experimental loss of foundation species: consequences for dynamics at ecotones across heterogeneous landscapes

Long‐term experimental loss of foundation species: consequences for dynamics at ecotones across heterogeneous landscapes

CO2ENHANCES PRODUCTIVITY, ALTERS SPECIES COMPOSITION, AND REDUCES DIGESTIBILITY OF SHORTGRASS STEPPE VEGETATION

Novel Root Fungal Consortium Associated with a Dominant Desert Grass

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CO₂ENHANCES PRODUCTIVITY, ALTERS SPECIES COMPOSITION, AND REDUCES DIGESTIBILITY OF SHORTGRASS STEPPE VEGETATION