Pub Date : 2003-09-01DOI: 10.2458/AZU_JRM_V56I5_BEUKES
P. C. Beukes, R. Cowling
Non-selective grazing (NSG) is a relatively novel way of farming livestock in the Nama Karoo of South Africa. Our key question was how heavy grazing under this high-intensity, low-frequency grazing system would impact on certain soil properties. The study was designed to compare the impacts of NSG (treatment) with no grazing (control) in terms of: (1) amount of soil organic carbon (OC); (2) soil microbial respiration rates; (3) soil stability and infiltration properties. The treatment significantly lowered the amount of OC in the topsoil. Microbial respiration rates corresponded with the fertile patch matrix in both treatment and control with significantly higher respiration rates measured under plants compared to open, unvegetated areas. Respiration rates in treatment open areas were significantly higher than in control open areas. There was a trend (P < 0.1) for higher aggregate stability, final infiltration rate and cumulative infiltration for treatment open soils compared to controls during an initial rain event of 44 mm hour-1 in a rainfall simulator. During a second rain event on sealed soils only aggregate stability was significantly higher for treatment compared to control soils. We conclude that the short-duration, low-frequency, intensive herbivory by livestock under the non-selective grazing system resulted in a more active microbial community, which turned over organic matter more rapidly and led to higher soil stability and infiltration capacity of open, unvegetated soils. We present this as an example of conditions where herding by high densities of large herbivores can have positive impacts on soil quality. DOI:10.2458/azu_jrm_v56i5_beukes
非选择性放牧(NSG)是南非纳马卡鲁地区一种相对较新的畜牧业方式。我们的关键问题是，在这种高强度、低频率的放牧系统下，重度放牧将如何影响某些土壤性质。本研究旨在比较NSG(处理)与不放牧(对照)在以下方面的影响:(1)土壤有机碳(OC)量;(2)土壤微生物呼吸速率;(3)土壤稳定性和入渗特性。该处理显著降低了表层土壤的有机碳含量。微生物呼吸速率在处理和对照中都与肥沃斑块基质相对应，在植物下测量的呼吸速率显著高于开放的无植被区域。试验区的呼吸速率显著高于对照组。在降雨模拟器中，在初始降雨为44 mm h -1时，处理过的开放性土壤的团聚体稳定性、最终入渗率和累积入渗率均有高于对照的趋势(P < 0.1)。在第二次降雨过程中，封闭土壤只有处理后的团聚体稳定性显著高于对照土壤。结果表明，在非选择性放牧制度下，短时间、低频率、集约化的牲畜放牧使开阔、无植被的土壤微生物群落更加活跃，有机质周转速度更快，土壤稳定性和入渗能力更高。我们将此作为大型食草动物高密度放牧对土壤质量产生积极影响的一个例子。DOI: 10.2458 / azu_jrm_v56i5_beukes
{"title":"Non-selective grazing impacts on soil-properties of the Nama Karoo.","authors":"P. C. Beukes, R. Cowling","doi":"10.2458/AZU_JRM_V56I5_BEUKES","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I5_BEUKES","url":null,"abstract":"Non-selective grazing (NSG) is a relatively novel way of farming livestock in the Nama Karoo of South Africa. Our key question was how heavy grazing under this high-intensity, low-frequency grazing system would impact on certain soil properties. The study was designed to compare the impacts of NSG (treatment) with no grazing (control) in terms of: (1) amount of soil organic carbon (OC); (2) soil microbial respiration rates; (3) soil stability and infiltration properties. The treatment significantly lowered the amount of OC in the topsoil. Microbial respiration rates corresponded with the fertile patch matrix in both treatment and control with significantly higher respiration rates measured under plants compared to open, unvegetated areas. Respiration rates in treatment open areas were significantly higher than in control open areas. There was a trend (P < 0.1) for higher aggregate stability, final infiltration rate and cumulative infiltration for treatment open soils compared to controls during an initial rain event of 44 mm hour-1 in a rainfall simulator. During a second rain event on sealed soils only aggregate stability was significantly higher for treatment compared to control soils. We conclude that the short-duration, low-frequency, intensive herbivory by livestock under the non-selective grazing system resulted in a more active microbial community, which turned over organic matter more rapidly and led to higher soil stability and infiltration capacity of open, unvegetated soils. We present this as an example of conditions where herding by high densities of large herbivores can have positive impacts on soil quality. DOI:10.2458/azu_jrm_v56i5_beukes","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":"61 1","pages":"547-552"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73583242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The objective of this study was to identify and model environmental and management factors associated with cattle feces deposition patterns across annual rangeland watersheds in the Sierra Nevada foothills. Daily cattle fecal load accumulation rates were calculated from seasonal fecal loads measured biannually on 40 m 2 permanent transects distributed across a 150.5 ha pasture in Madera County, Calif. during the 4 year period from 1995 through 1998. Associations between daily fecal load per season, livestock management, and environmental factors measured for each transect were determined using a linear mixed effects model. Cattle feces distribution patterns were significantly associated with location of livestock attractants, slope percentage, slope aspect, hydrologic position, and season. Transects located in livestock concentration areas experienced a significantly higher daily fecal load compared to transects outside of these concentration areas (P < 0.001). Percent slope was negatively associated with daily fecal load, but this association had a significant interaction with slope aspect (P = 0.02). Daily fecal load was significantly lower during the wet season compared to the dry season (P = 0.002). Daily fecal loading rates across hydrologic positions were dependent upon season. Our results illustrate the opportunities to reduce the risk of water quality contamination by strategic placement of cattle attractants, and provide a means to predict cattle feces deposition based upon inherent watershed characteristics and management factors.
{"title":"Spatial and temporal patterns of cattle feces deposition on rangeland","authors":"K. Tate, E. Atwill, N. McDougald, M. George","doi":"10.2307/4003833","DOIUrl":"https://doi.org/10.2307/4003833","url":null,"abstract":"The objective of this study was to identify and model environmental and management factors associated with cattle feces deposition patterns across annual rangeland watersheds in the Sierra Nevada foothills. Daily cattle fecal load accumulation rates were calculated from seasonal fecal loads measured biannually on 40 m 2 permanent transects distributed across a 150.5 ha pasture in Madera County, Calif. during the 4 year period from 1995 through 1998. Associations between daily fecal load per season, livestock management, and environmental factors measured for each transect were determined using a linear mixed effects model. Cattle feces distribution patterns were significantly associated with location of livestock attractants, slope percentage, slope aspect, hydrologic position, and season. Transects located in livestock concentration areas experienced a significantly higher daily fecal load compared to transects outside of these concentration areas (P < 0.001). Percent slope was negatively associated with daily fecal load, but this association had a significant interaction with slope aspect (P = 0.02). Daily fecal load was significantly lower during the wet season compared to the dry season (P = 0.002). Daily fecal loading rates across hydrologic positions were dependent upon season. Our results illustrate the opportunities to reduce the risk of water quality contamination by strategic placement of cattle attractants, and provide a means to predict cattle feces deposition based upon inherent watershed characteristics and management factors.","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":"99 1","pages":"432-438"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79299223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wyoming Coal Rules and Regulations require shrubs be returned to mined land and that revegetation "...be self renewing." We evaluated seed production and seed quality of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis (Beetle & Young)) by measuring the effect of mining, herbivory, and environmental modification on seed production at 5 sites on the Dave Johnston Coal Mine near Glenrock, Wyo. Mined-land stands ranged in age from 5 to >20 years. Single sagebrush plants on mined, and adjacent unmined land were treated by: (1) fabric mulch around the base, (2) windbreak on the north and west, (3) both mulch and windbreak, and (4) neither windbreak nor mulch. Plants were fenced and compared with unfenced, untreated, neighboring plants. Seeds were harvested for 3 years and data were collected on seed-stalk numbers, bulk weight of seeds produced, and seed quality. Fenced mined-land plants produced several times more seeds than fenced plants on adjacent unmined land. There was no difference in seed quality. Treatments to modify the plant environment resulted in some benefits but fencing had a greater effect on seed-quality parameters than did planned treatments. We conclude the sagebrush seed-production potential on reclaimed lands such as those of the Dave Johnston Coal Mine is equal to, and often several times greater than that of adjacent unmined lands. However, browsing by wild ungulates can eliminate the mined-land yield advantage. DOI:10.2458/azu_jrm_v56i5_booth
{"title":"Wyoming big sagebrush seed production from mined and unmined rangelands.","authors":"D. T. Booth, Y. Bai, E. E. Roos","doi":"10.2307/4003848","DOIUrl":"https://doi.org/10.2307/4003848","url":null,"abstract":"Wyoming Coal Rules and Regulations require shrubs be returned to mined land and that revegetation \"...be self renewing.\" We evaluated seed production and seed quality of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis (Beetle & Young)) by measuring the effect of mining, herbivory, and environmental modification on seed production at 5 sites on the Dave Johnston Coal Mine near Glenrock, Wyo. Mined-land stands ranged in age from 5 to >20 years. Single sagebrush plants on mined, and adjacent unmined land were treated by: (1) fabric mulch around the base, (2) windbreak on the north and west, (3) both mulch and windbreak, and (4) neither windbreak nor mulch. Plants were fenced and compared with unfenced, untreated, neighboring plants. Seeds were harvested for 3 years and data were collected on seed-stalk numbers, bulk weight of seeds produced, and seed quality. Fenced mined-land plants produced several times more seeds than fenced plants on adjacent unmined land. There was no difference in seed quality. Treatments to modify the plant environment resulted in some benefits but fencing had a greater effect on seed-quality parameters than did planned treatments. We conclude the sagebrush seed-production potential on reclaimed lands such as those of the Dave Johnston Coal Mine is equal to, and often several times greater than that of adjacent unmined lands. However, browsing by wild ungulates can eliminate the mined-land yield advantage. DOI:10.2458/azu_jrm_v56i5_booth","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":"14 1","pages":"542-546"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81523769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding landscape conversion is vital for assessing the impacts of ecological and anthropogenic disturbances at regional and global scales. Since rangelands cover nearly half of the global land surface, and because a large part of rangelands is located in semi-arid ecosystems, they serve as critical land cover types for determining regional biodiversity, global biogeochemical cycles, and energy and gas fluxes. For such vast ecosystems, satellite imagery is often used to inventory biophysical materials and man-made features on Earth's surface. The large area coverage and frequent acquisition cycle of remotely sensed satellite images make earth observation data useful for monitoring land conversion rates at different spatial scales. Remote sensing could also be used for temporal assessment of semi-arid ecosystems by providing complimentary sets of rangeland health indicators. In this paper, temporal satellite data from multiple sensors were examined to quantify land use and land cover change, and to relate spatial configuration and composition to landscape structure and pattern. The findings were correlated with the role of fire to better understand ecological functionality and human and/or natural activities that are generating environmental stressors in a rapidly developing, semi-urban census division located in southeastern Arizona. Results indicate that conversion of a fire-suppressed native grassland area has 2 spatial components; in the rural areas, grass is being eliminated by increasingly homogeneous shrub and mesquite-dominated areas, whereas in the urban and suburban areas, grass as well shrubs and mesquite are being eliminated by a fragmented and expanding built landscape. DOI:10.2458/azu_jrm_v56i5_wallace
{"title":"Remote sensing for cover change assessment in southeast Arizona.","authors":"O. Wallace, J. Qi, P. Heilma, R. Marsett","doi":"10.2307/4003829","DOIUrl":"https://doi.org/10.2307/4003829","url":null,"abstract":"Understanding landscape conversion is vital for assessing the impacts of ecological and anthropogenic disturbances at regional and global scales. Since rangelands cover nearly half of the global land surface, and because a large part of rangelands is located in semi-arid ecosystems, they serve as critical land cover types for determining regional biodiversity, global biogeochemical cycles, and energy and gas fluxes. For such vast ecosystems, satellite imagery is often used to inventory biophysical materials and man-made features on Earth's surface. The large area coverage and frequent acquisition cycle of remotely sensed satellite images make earth observation data useful for monitoring land conversion rates at different spatial scales. Remote sensing could also be used for temporal assessment of semi-arid ecosystems by providing complimentary sets of rangeland health indicators. In this paper, temporal satellite data from multiple sensors were examined to quantify land use and land cover change, and to relate spatial configuration and composition to landscape structure and pattern. The findings were correlated with the role of fire to better understand ecological functionality and human and/or natural activities that are generating environmental stressors in a rapidly developing, semi-urban census division located in southeastern Arizona. Results indicate that conversion of a fire-suppressed native grassland area has 2 spatial components; in the rural areas, grass is being eliminated by increasingly homogeneous shrub and mesquite-dominated areas, whereas in the urban and suburban areas, grass as well shrubs and mesquite are being eliminated by a fragmented and expanding built landscape. DOI:10.2458/azu_jrm_v56i5_wallace","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":"69 6 1","pages":"402-409"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80889830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-09-01DOI: 10.2458/AZU_JRM_V56I5_JOHNSON
Douglas A. Johnson, N. Saliendra, John W. Walker, J. Hendrickson
Because of their expansiveness, sagebrush (Artemisia spp.)-steppe rangelands could contribute significantly to the global carbon budget. However, it is important to determine if there are differences between methods for determining CO2 fluxes on these rangelands. The objective of this study was to compare the Bowen ratio-energy balance and canopy chamber techniques for measuring CO2 fluxes in a sagebrush-steppe ecosystem. A Bowen ratio-energy balance system was installed at a sagebrush-steppe site near Dubois, Ida., U.S.A to continuously measure the vertical gradients of air temperature, water vapor, and CO2 concentration in conjunction with associated micrometeorological characteristics. The canopy chamber technique, which employed a 1-m2 (1,020 liter) clear plexiglass/plastic film chamber in combination with a portable gas exchange system, was used periodically during May through August across 4 years (1996-1999) to obtain instantaneous measurements of CO2 fluxes across 3 replicate blocks during a 2-min. measurement period. For the same measurement dates and times across the 4 years of study, CO2 fluxes ranged from -0.22 to 0.55 mg m-2 sec-1 for the Bowen ratio-energy balance technique and from -0.18 to 0.48 mg m-2 sec-1 for the canopy chamber technique. Estimates of CO2 fluxes by the 2 techniques were not statistically different (P > 0.05) for the early (May) and mid-season (June to mid-July) portions of the growing season; however, fluxes measured by the 2 techniques were significantly different (P < 0.05) for the late-season period (late-July to late-August). Despite this difference during the hot-dry, late-season period, flux estimates from the 2 techniques were significantly and positively correlated during the early (r2 = 0.71), mid- (r2 = 0.88), and late- (r2 = 0.72) season periods. Thus, both techniques showed similar patterns of CO2 fluxes at our sagebrush-steppe study site across 4 years of study, although caution should be used when the canopy chamber technique is used during hot, dry conditions. DOI:10.2458/azu_jrm_v56i5_johnson
{"title":"Bowen ratio versus canopy chamber CO2 fluxes on sagebrush rangeland","authors":"Douglas A. Johnson, N. Saliendra, John W. Walker, J. Hendrickson","doi":"10.2458/AZU_JRM_V56I5_JOHNSON","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I5_JOHNSON","url":null,"abstract":"Because of their expansiveness, sagebrush (Artemisia spp.)-steppe rangelands could contribute significantly to the global carbon budget. However, it is important to determine if there are differences between methods for determining CO2 fluxes on these rangelands. The objective of this study was to compare the Bowen ratio-energy balance and canopy chamber techniques for measuring CO2 fluxes in a sagebrush-steppe ecosystem. A Bowen ratio-energy balance system was installed at a sagebrush-steppe site near Dubois, Ida., U.S.A to continuously measure the vertical gradients of air temperature, water vapor, and CO2 concentration in conjunction with associated micrometeorological characteristics. The canopy chamber technique, which employed a 1-m2 (1,020 liter) clear plexiglass/plastic film chamber in combination with a portable gas exchange system, was used periodically during May through August across 4 years (1996-1999) to obtain instantaneous measurements of CO2 fluxes across 3 replicate blocks during a 2-min. measurement period. For the same measurement dates and times across the 4 years of study, CO2 fluxes ranged from -0.22 to 0.55 mg m-2 sec-1 for the Bowen ratio-energy balance technique and from -0.18 to 0.48 mg m-2 sec-1 for the canopy chamber technique. Estimates of CO2 fluxes by the 2 techniques were not statistically different (P > 0.05) for the early (May) and mid-season (June to mid-July) portions of the growing season; however, fluxes measured by the 2 techniques were significantly different (P < 0.05) for the late-season period (late-July to late-August). Despite this difference during the hot-dry, late-season period, flux estimates from the 2 techniques were significantly and positively correlated during the early (r2 = 0.71), mid- (r2 = 0.88), and late- (r2 = 0.72) season periods. Thus, both techniques showed similar patterns of CO2 fluxes at our sagebrush-steppe study site across 4 years of study, although caution should be used when the canopy chamber technique is used during hot, dry conditions. DOI:10.2458/azu_jrm_v56i5_johnson","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":"65 1","pages":"517-523"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81400967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tannins are secondary metabolites that may influence feeding by mammals on plants. We analyzed hydrolyzable and condensed tannins in 30 plant species consumed by livestock and deer, as a preliminary attempt to study their possible implications on browsing and grazing in forest ecosystems. Heathers (Ericaceae) and plants of the Rose (Rosaceae) family had tannins, while forbs, grasses and shrubs other than the heathers did not show astringency properties. We found the highest tannin content of all the species in Rubus sp., with the highest value around 180 mg TAE/g dry weight in spring. Potentilla erecta, Alnus glutinosa and Quercus robur were next with 57 to 44 mg TAE/g dw. Total tannins in heathers ranged from 22 to 36 mg TAE/g dw. Levels of condensed tannins were higher than hydrolyzable for most of the species. Only Betula alba, Calluna vulgaris, Pteridium aquilinum and Vaccinium myrtillus had 100% hydrolyzable tannins. Tannin content of the species changed seasonally with highest values during the growing season, corresponding to late winter or early spring, depending on the species. DOI:10.2458/azu_jrm_v56i5_gonzalez-hernandez
{"title":"Research observation: Hydrolyzable and condensed tannins in plants of the northwest","authors":"M. González-Hernández, J. Karchesy, E. Starkey","doi":"10.2307/4003837","DOIUrl":"https://doi.org/10.2307/4003837","url":null,"abstract":"Tannins are secondary metabolites that may influence feeding by mammals on plants. We analyzed hydrolyzable and condensed tannins in 30 plant species consumed by livestock and deer, as a preliminary attempt to study their possible implications on browsing and grazing in forest ecosystems. Heathers (Ericaceae) and plants of the Rose (Rosaceae) family had tannins, while forbs, grasses and shrubs other than the heathers did not show astringency properties. We found the highest tannin content of all the species in Rubus sp., with the highest value around 180 mg TAE/g dry weight in spring. Potentilla erecta, Alnus glutinosa and Quercus robur were next with 57 to 44 mg TAE/g dw. Total tannins in heathers ranged from 22 to 36 mg TAE/g dw. Levels of condensed tannins were higher than hydrolyzable for most of the species. Only Betula alba, Calluna vulgaris, Pteridium aquilinum and Vaccinium myrtillus had 100% hydrolyzable tannins. Tannin content of the species changed seasonally with highest values during the growing season, corresponding to late winter or early spring, depending on the species. DOI:10.2458/azu_jrm_v56i5_gonzalez-hernandez","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":"51 1","pages":"461-465"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87372409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-09-01DOI: 10.2458/AZU_JRM_V56I5_KIRBY
D. Kirby, R. Lym, J. Sterling, C. Sieg
The western prairie fringed orchid (Platanthera praeclara Sheviak and Bowles) is a threatened species of the tallgrass prairie. Invasion by leafy spurge (Euphorbia esula L.) is a serious threat to western prairie fringed orchid habitat. The objectives of this study were to develop a herbicide treatment to control leafy spurge while sustaining western prairie fringed orchid populations and to evaluate the soil seedbank composition of leafy spurge-infested sites to guide long-term management strategies. Quinclorac (3,7-dichloro-8-quinolinecarboxylic acid), imazapic {(+/-)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2=yl]-5-methyl-3-pyridinecarboxylic acid}, and glyphosate [N-(phosphonomethyl)glycine] plus 2,4-D (2,4-dichlorophenoxy acetic acid) were applied in the fall for 2 consecutive years, and changes in leafy spurge cover, density, yield, and herbaceous yield were assessed. In a separate study, quinclorac, imazapic, and glyphosate plus 2,4-D were each fall-applied to 12 western prairie fringed orchids and assessed for reoccurrence and density of orchids 1-year after treatment. Quinclorac and imazapic, but not glyphosate plus 2,4-D, reduced leafy spurge cover, density, and yield without causing deleterious effects to associated native herbaceous cover and yields. Western prairie fringed orchid reoccurrence and density were unaffected by any herbicide 1 year after treatment. Soil cores were removed in spring and fall following the first year herbicide treatment, washed and placed in trays. Seedlings were allowed to germinate for 16 weeks in the greenhouse. Over 50 plant species were identified in the soil seedbank, of which approximately 60% were early seral species indicative of disturbance. Given the dominance of leafy spurge in the seed bank, a long-term management program to control this noxious species is warranted. Although these results are promising, longer-term studies need be conducted to ensure that repeated herbicide treatments do not harm the western prairie fringed orchid. DOI:10.2458/azu_jrm_v56i5_kirby
{"title":"Observation: Leafy spurge control in western prairie fringed orchid habitat","authors":"D. Kirby, R. Lym, J. Sterling, C. Sieg","doi":"10.2458/AZU_JRM_V56I5_KIRBY","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I5_KIRBY","url":null,"abstract":"The western prairie fringed orchid (Platanthera praeclara Sheviak and Bowles) is a threatened species of the tallgrass prairie. Invasion by leafy spurge (Euphorbia esula L.) is a serious threat to western prairie fringed orchid habitat. The objectives of this study were to develop a herbicide treatment to control leafy spurge while sustaining western prairie fringed orchid populations and to evaluate the soil seedbank composition of leafy spurge-infested sites to guide long-term management strategies. Quinclorac (3,7-dichloro-8-quinolinecarboxylic acid), imazapic {(+/-)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2=yl]-5-methyl-3-pyridinecarboxylic acid}, and glyphosate [N-(phosphonomethyl)glycine] plus 2,4-D (2,4-dichlorophenoxy acetic acid) were applied in the fall for 2 consecutive years, and changes in leafy spurge cover, density, yield, and herbaceous yield were assessed. In a separate study, quinclorac, imazapic, and glyphosate plus 2,4-D were each fall-applied to 12 western prairie fringed orchids and assessed for reoccurrence and density of orchids 1-year after treatment. Quinclorac and imazapic, but not glyphosate plus 2,4-D, reduced leafy spurge cover, density, and yield without causing deleterious effects to associated native herbaceous cover and yields. Western prairie fringed orchid reoccurrence and density were unaffected by any herbicide 1 year after treatment. Soil cores were removed in spring and fall following the first year herbicide treatment, washed and placed in trays. Seedlings were allowed to germinate for 16 weeks in the greenhouse. Over 50 plant species were identified in the soil seedbank, of which approximately 60% were early seral species indicative of disturbance. Given the dominance of leafy spurge in the seed bank, a long-term management program to control this noxious species is warranted. Although these results are promising, longer-term studies need be conducted to ensure that repeated herbicide treatments do not harm the western prairie fringed orchid. DOI:10.2458/azu_jrm_v56i5_kirby","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":"98 1","pages":"466-473"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85768330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-09-01DOI: 10.2458/AZU_JRM_V56I5_COLBERG
Tyler J. Colberg, J. Romo
Clubmoss (Selaginella densa Rydb.), a low growing, vascular cryptogam forms carpet-like mats that cover up to 80% of the ground in the Northern Mixed Prairie. Many range managers believe clubmoss competes with grasses for water or intercepts precipitation and negatively affects plant water relations and productivity. The objective of these studies was to test the hypothesis that precipitation has greater effects on leaf xylem water potentials (Leafxwp) and plant productivity than clubmoss. Studies examined the effects of clubmoss on Leafxwp of Junegrass (Koeleria cristata Pers.) and blue grama (Bouteloua gracilis [HBK.] Lag.), and productivity of forbs and graminoids by: 1) irrigating or reducing precipitation relative to natural precipitation; 2) removing clubmoss relative to clubmoss present, and; 3) irrigating with 0.0 to 25 mm of water when clubmoss was present or removed. Leafxwp of Junegrass and blue grama were unaffected by clubmoss through the growing season (P = 0.33), but Leafxwp were lowest (P < or = 0.05) when precipitation was reduced relative to the control and when irrigating. Standing crop of forbs was similar in the control and clubmoss removal treatment (P = 0.22) and among precipitation treatments (P = 0.13), averaging 28 g m-2 (SE = 2.2). Graminoid standing crop was unaffected by clubmoss (P = 0.35) and was greatest (P = 0.02) when irrigated (74 g m-2), intermediate in the control (53 g m-2), and least (36 g m-2) with reduced precipitation (SE = 8.7). Clubmoss did not affect (P = 0.70) total standing crop; total standing crop declined from 102 g m-2 when irrigated to 76 g m-2 in the control, and 69 g m-2 (SE = 9.0) with reduced precipitation. Clubmoss had no influence (P = 0.06) on Leafxwp when irrigated with 0 to 25 mm of water. The decline in Leafxwp from 1 to 7 days after irrigation was the product of the interacting effects of the amount of water applied and days after irrigation (P = 0.03). More than 10 mm of irrigation water were required to impart a significant increase (P < or =0.05) in Leafxwp. The hypothesis that clubmoss reduces productivity of associated plants in the Northern Mixed Prairie by increasing water stress is rejected. Similarly clubmoss does not reduce plant water stress or increase production. Precipitation amounts overshadow any effects clubmoss has on Leafxwp and plant production. Range managers in the Northern Mixed Prairie may want to consider maximizing the effectiveness of precipitation in this water-limited environment instead of focusing on reducing or attempting to eliminate clubmoss. DOI:10.2458/azu_jrm_v56i5_colberg
松苔(Selaginella densa Rydb.)，一种低矮的维管隐生植物，形成地毯状的垫子，覆盖了北部混合草原80%的土地。许多牧场管理者认为藓类会与草类争夺水分或拦截降水，对植物的水分关系和生产力产生负面影响。这些研究的目的是验证降水对叶片木质部水势(Leafxwp)和植物生产力的影响大于苔藓的假设。研究了棒藓对六月草(Koeleria cristata Pers.)和蓝草(Bouteloua gracilis [HBK.])叶片的影响。(1)相对于自然降水，灌溉或减少降水;2)相对于存在的杆苔去除杆苔;3)当出现或除去苔藓时，用0.0 ~ 25mm的水灌溉。整个生长季中，杨茅和蓝茅叶片的叶片xwp均未受苔藓影响(P = 0.33)，但在降水相对于对照减少和灌溉时叶片xwp最低(P <或= 0.05)。在对照和去除藓类处理中(P = 0.22)，在降水处理中(P = 0.13)，牧草的直立产量相似，平均为28 g m-2 (SE = 2.2)。禾草类直立作物不受杆藓的影响(P = 0.35)，在灌水(74 g m-2)时最大(P = 0.02)，在对照(53 g m-2)时居中，在降水减少(SE = 8.7)时最小(36 g m-2)。苔藓对总直立作物没有影响(P = 0.70);随着降水的减少，林分作物总量从灌水时的102 g m-2下降到对照时的76 g m-2，减少到69 g m-2 (SE = 9.0)。在0 ~ 25 mm的水灌溉条件下，藓类对Leafxwp无显著影响(P = 0.06)。灌后1 ~ 7 d叶片叶片光合活性下降是施水量与灌后天数交互作用的结果(P = 0.03)。超过10毫米的灌溉用水要求传授显著增加(P <或在Leafxwp = 0.05)。通过增加水分胁迫来降低北方混合草原相关植物生产力的假设被否定。同样地，苔藓不会减少植物的水分胁迫或增加产量。降水量掩盖了clubmoss对Leafxwp和植物产量的影响。北部混合草原的牧场管理者可能想要考虑在这种水资源有限的环境中最大限度地提高降水的有效性，而不是专注于减少或试图消除苔藓。DOI: 10.2458 / azu_jrm_v56i5_colberg
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Book description: In recent years, the concept of “sustainable development” has promoted a great expansion of bureaucratic activity at the regional, national and international level. The sustainable-development movement claims to support environmental and human well-being, but A Poverty of Reason: Sustainable Development and Economic Growth, by Wilfred Beckerman, shows this is not the case. Support for sustainable development is based on confusion about its ethical implications and on a flagrant disregard of the relevant factual evidence.
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T. A. Jones, D. Nielson, J. Arredondo, M. Redinbaugh
Squirreltail (Elymus elymoides, E. multisetus) is a complex of 5 taxa whose systematic interrelationships are uncertain. Our objectives were to determine whether the 3 taxa studied here, Elymus elymoides ssp. elymoides, E. elymoides ssp. brevifolius, and E. multisetus, can be distinguished by several ecological and physiological traits and whether geographical origin is correlated with these traits across accessions within taxa. A multivariate principal component analysis of materials collected in the 10 contiguous western states successfully distinguished taxa, but no pair of the 3 taxa appeared to be more ecologically similar than any other pair. Elymus elymoides ssp. elymoides, which prevails in the semi-arid cold desert, was shortest and exhibited the lowest total plant dry-matter, earliest phenology, and lowest seed mass. Elymus elymoides ssp. brevifolius, which prevails in the Rocky Mountains, exhibited slowest emergence, highest specific root length, lowest nitrate reductase activity, and lowest root-to-shoot ratio. Elymus multisetus, which is most common in areas with relatively warm springs, exhibited fastest emergence (particularly from deep seeding), greatest root length, and greatest root-to-shoot ratio. Elymus elymoides ssp. brevifolius accessions clustered into 3 groups: late-maturing high-seed mass accessions originating in Colorado, New Mexico, and Arizona (Group A), early-maturing low-seed mass accessions originating in Colorado and Utah (Group B), and intermediate-maturing low-seed mass accessions originating in the Snake River Plain of southern Idaho (Group C). The ecologically distinct subspecies and groups within ssp. brevifolius are indicative of the highly ecotypic nature of the squirreltails, suggesting that restoration practitioners should match site with genetically and ecologically appropriate plant material for these species.
松鼠尾(Elymus elymoides, E. multisetus)是一个由5个分类群组成的复合体，它们之间的系统相互关系尚不确定。我们的目的是确定这里研究的3个分类群，elyymus elymoides ssp。鞘翅目，鞘翅目;短叶橐吾(brevifolius)和多毛橐吾(E. multisetus)在分类群内的生态生理特征及其地理来源是否与这些特征相关。对西部10个相邻州收集的资料进行多元主成分分析，成功地区分了3个类群，但没有一对类群表现出比其他类群更相似的生态相似性。羊角草在半干旱寒冷沙漠中普遍存在的鞘翅属植物，其长度最短，总干物质最低，物候最早，种子质量最低。羊角草在落基山脉常见的短叶草，其出苗最慢，比根长最高，硝还原酶活性最低，根冠比最低。在春季相对温暖的地区最常见的羊草(Elymus multisetus)出苗速度最快(特别是深播)，根系长度最大，根冠比最大。羊角草短叶茅属植物可分为3个类群:起源于科罗拉多州、新墨西哥州和亚利桑那州的晚熟高种子质量类群(A组)，起源于科罗拉多州和犹他州的早熟低种子质量类群(B组)，以及起源于爱达荷州南部蛇河平原的中熟低种子质量类群(C组)。短尾草是松鼠高度生态型的标志，这表明恢复从业者应该为这些物种匹配遗传和生态适宜的植物材料。
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