Pub Date : 2003-07-01DOI: 10.2458/AZU_JRM_V56I4_BURBOA-CABRERA
F. R. Burboa-Cabrera, W. Schacht, Bruce Anderson
The relationship between stocking density and grazing distribution was studied in eastern Nebraska pastures seeded to a warm-season, tall-grass mixture and grazed at 4 stocking densities: 9, 18, 27, and 54 steers ha-1. Each of 4 pastures was divided into 4 paddocks ranging in size from 0.18 to 1.12 ha. Paddocks within each pasture were grazed rotationally by 10 steers averaging 282 kg during 3 consecutive cycles (12, 36, and 24 days) from early June to late August in 1995 and 1996. Transects 12-m long were established in a grid pattern in each paddock. Six tillers each of big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) were marked permanently in each transect. Height and leaf length of marked tillers were measured before and after grazing in the last 2 grazing cycles in both years. Utilization was estimated by the reduction in tiller height or leaf length. Estimates of grazing distribution were based on a uniformity index, which was calculated by summing the absolute differences of tiller height or leaf length between adjacent transects. Stocking density generally did not affect (P > 0.05) tiller height reduction which ranged from 19 to 22 cm and from 29 to 38 cm among the stocking densities in 1995 and 1996, respectively. In most grazing cycles, leaf length reduction for big bluestem was greater (P 0.05) by stocking density but big bluestem was grazed more evenly (P < 0.05) than switchgrass in the last cycle in each year. Stocking densities as high as 54 steers ha-1 on warm-season, tall-grass mixtures do not appear to be a major factor in affecting spatial grazing distribution or forage plant selection. DOI:10.2458/azu_jrm_v56i4_burboa-cabrera
{"title":"Utilization and grazing distribution of cattle at 4 stocking densities.","authors":"F. R. Burboa-Cabrera, W. Schacht, Bruce Anderson","doi":"10.2458/AZU_JRM_V56I4_BURBOA-CABRERA","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I4_BURBOA-CABRERA","url":null,"abstract":"The relationship between stocking density and grazing distribution was studied in eastern Nebraska pastures seeded to a warm-season, tall-grass mixture and grazed at 4 stocking densities: 9, 18, 27, and 54 steers ha-1. Each of 4 pastures was divided into 4 paddocks ranging in size from 0.18 to 1.12 ha. Paddocks within each pasture were grazed rotationally by 10 steers averaging 282 kg during 3 consecutive cycles (12, 36, and 24 days) from early June to late August in 1995 and 1996. Transects 12-m long were established in a grid pattern in each paddock. Six tillers each of big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) were marked permanently in each transect. Height and leaf length of marked tillers were measured before and after grazing in the last 2 grazing cycles in both years. Utilization was estimated by the reduction in tiller height or leaf length. Estimates of grazing distribution were based on a uniformity index, which was calculated by summing the absolute differences of tiller height or leaf length between adjacent transects. Stocking density generally did not affect (P > 0.05) tiller height reduction which ranged from 19 to 22 cm and from 29 to 38 cm among the stocking densities in 1995 and 1996, respectively. In most grazing cycles, leaf length reduction for big bluestem was greater (P 0.05) by stocking density but big bluestem was grazed more evenly (P < 0.05) than switchgrass in the last cycle in each year. Stocking densities as high as 54 steers ha-1 on warm-season, tall-grass mixtures do not appear to be a major factor in affecting spatial grazing distribution or forage plant selection. DOI:10.2458/azu_jrm_v56i4_burboa-cabrera","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78565148","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 : 2003-07-01DOI: 10.2458/AZU_JRM_V56I4_GONNET
J. Gonnet, J. Guevara, O. R. Estevez
The study analyzed the basal area and density of perennial grasses along a cattle grazing intensity gradient away from a water development. Several mechanisms explaining combinations of changes in basal area and density with increasing grazing intensity were proposed. There was a curve-linear gradient of decreasing utilization of grasses at greater distances from water, and that gradient declined at greater distances from water. Basal diameter and density of 8 grasses were recorded at 11 distances from water ranged from 0.1 to 4.6 km within 16, 1-m2 plots for each distance. Circular basal area for each species was derived from its mean basal diameter. Plant density was estimated counting each tussock for bunchgrasses and each tiller as an individual for the 1 rhizomatous grass. The abundance of basal area and density to the gradient of distance from water was analyzed for grasses grouped according to their selectivity by cattle (undesirable, preferred, desirable, and secondary preference) and for the major preferred grass, Chloris castilloniana Lillo & Parodi and the 2 undesirable grasses, Aristida inversa Haeck. and A. mendocina Phil. Distance from water was regressed separately on basal area and on density for each selectivity group and each individual species. Basal area of total, undesirable, and desirable grasses increased up to intermediate distances from water and decreased at sites farther from water. Basal area of both the preferred grasses combined and the major preferred species increased linearly with distance from water. Basal area of A. inversa showed the same trend as the undesirable grasses while basal area of A. mendocina showed no definite pattern with increasing grazing intensity. Basal area of secondary preference species showed no definite pattern with distance from water. Density of total and desirable grasses increased up to intermediate distances from water and decreased at sites farther from water. Density of preferred species combined and the major preferred grass increased linearly with distance from water. Density of the 2 undesirable grasses and the secondary preference grass showed no definite trend with increasing grazing intensity. The combined patterns of basal area and density across the grazing intensity gradient suggest that the expression of recruitment, mortality, and plant growth (or shrinkage) in relation to grazing intensity varies among species and at different levels of grazing intensity. However, controlled experiments are needed to decipher the relative contributions of grazing intensity, neighboring species composition, or vegetation patterns existing before the establishment of the livestock water in the patterns of abundance. DOI:10.2458/azu_jrm_v56i4_gonnet
{"title":"Perennial grass abundance along a grazing gradient in Mendoza, Argentina.","authors":"J. Gonnet, J. Guevara, O. R. Estevez","doi":"10.2458/AZU_JRM_V56I4_GONNET","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I4_GONNET","url":null,"abstract":"The study analyzed the basal area and density of perennial grasses along a cattle grazing intensity gradient away from a water development. Several mechanisms explaining combinations of changes in basal area and density with increasing grazing intensity were proposed. There was a curve-linear gradient of decreasing utilization of grasses at greater distances from water, and that gradient declined at greater distances from water. Basal diameter and density of 8 grasses were recorded at 11 distances from water ranged from 0.1 to 4.6 km within 16, 1-m2 plots for each distance. Circular basal area for each species was derived from its mean basal diameter. Plant density was estimated counting each tussock for bunchgrasses and each tiller as an individual for the 1 rhizomatous grass. The abundance of basal area and density to the gradient of distance from water was analyzed for grasses grouped according to their selectivity by cattle (undesirable, preferred, desirable, and secondary preference) and for the major preferred grass, Chloris castilloniana Lillo & Parodi and the 2 undesirable grasses, Aristida inversa Haeck. and A. mendocina Phil. Distance from water was regressed separately on basal area and on density for each selectivity group and each individual species. Basal area of total, undesirable, and desirable grasses increased up to intermediate distances from water and decreased at sites farther from water. Basal area of both the preferred grasses combined and the major preferred species increased linearly with distance from water. Basal area of A. inversa showed the same trend as the undesirable grasses while basal area of A. mendocina showed no definite pattern with increasing grazing intensity. Basal area of secondary preference species showed no definite pattern with distance from water. Density of total and desirable grasses increased up to intermediate distances from water and decreased at sites farther from water. Density of preferred species combined and the major preferred grass increased linearly with distance from water. Density of the 2 undesirable grasses and the secondary preference grass showed no definite trend with increasing grazing intensity. The combined patterns of basal area and density across the grazing intensity gradient suggest that the expression of recruitment, mortality, and plant growth (or shrinkage) in relation to grazing intensity varies among species and at different levels of grazing intensity. However, controlled experiments are needed to decipher the relative contributions of grazing intensity, neighboring species composition, or vegetation patterns existing before the establishment of the livestock water in the patterns of abundance. DOI:10.2458/azu_jrm_v56i4_gonnet","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73834356","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}
M. Abu-Zanat, F. M. Al-Hassanat, M. Alawi, G. Ruyle
The study was conducted at 3 locations in the arid region of Jordan to assess the seasonal changes of oxalate and tannins in Atriplex halimus L. and A. nummularia L. plants commonly used for revegetation of degraded rangelands. During spring and fall seasons, 20 shrubs of each species were selected randomly at each location, 20 similar twigs per shrub were clipped and analyzed for oxalate and tannins. Atriplex halimus contained higher levels of oxalate (7.00%) compared with A. nummularia plants (6.20%) (P < 0.001). Oxalate levels averaged 8.29 and 4.92% in spring and fall season, respectively. Plants of A. halimus accumulated more oxalate in spring than those of A. nummularia. Clipping had no effect on oxalate concentration. The seedlings of A. nummularia contained more oxalate than old plants whereas old shrubs of A. halimus contained more oxalate than the young seedlings. The browse of A. halimus contained more condensed and hydrolyzable tannins (1.05% and 0.67%, P < 0.0001) than A. nummularia (0.80% and 0.39%, P < 0.0001), respectively. Clipping had no effect on the levels of tannic phenols, condensed and hydrolyzable tannins. Young plants of the 2 species had higher levels of condensed tannins compared to older plants. However, seedlings of A. nummularia contained significantly higher levels of condensed tannins compared to A. nummularia seedlings (1.57% and 1.47%, respectively). Atriplex halimus synthesized more oxalate, tannic phenols, condensed and hydrolyzable tannins than A. nummularia. These secondary metabolites may explain the low palatability of Atriplex halimus compared to A. nummularia. DOI:10.2458/azu_jrm_v56i4_abu-zanat
{"title":"Oxalate and tannins assessment in Atriplex halimus L. and A. nummularia L.","authors":"M. Abu-Zanat, F. M. Al-Hassanat, M. Alawi, G. Ruyle","doi":"10.2307/4004041","DOIUrl":"https://doi.org/10.2307/4004041","url":null,"abstract":"The study was conducted at 3 locations in the arid region of Jordan to assess the seasonal changes of oxalate and tannins in Atriplex halimus L. and A. nummularia L. plants commonly used for revegetation of degraded rangelands. During spring and fall seasons, 20 shrubs of each species were selected randomly at each location, 20 similar twigs per shrub were clipped and analyzed for oxalate and tannins. Atriplex halimus contained higher levels of oxalate (7.00%) compared with A. nummularia plants (6.20%) (P < 0.001). Oxalate levels averaged 8.29 and 4.92% in spring and fall season, respectively. Plants of A. halimus accumulated more oxalate in spring than those of A. nummularia. Clipping had no effect on oxalate concentration. The seedlings of A. nummularia contained more oxalate than old plants whereas old shrubs of A. halimus contained more oxalate than the young seedlings. The browse of A. halimus contained more condensed and hydrolyzable tannins (1.05% and 0.67%, P < 0.0001) than A. nummularia (0.80% and 0.39%, P < 0.0001), respectively. Clipping had no effect on the levels of tannic phenols, condensed and hydrolyzable tannins. Young plants of the 2 species had higher levels of condensed tannins compared to older plants. However, seedlings of A. nummularia contained significantly higher levels of condensed tannins compared to A. nummularia seedlings (1.57% and 1.47%, respectively). Atriplex halimus synthesized more oxalate, tannic phenols, condensed and hydrolyzable tannins than A. nummularia. These secondary metabolites may explain the low palatability of Atriplex halimus compared to A. nummularia. DOI:10.2458/azu_jrm_v56i4_abu-zanat","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80613556","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 : 2003-07-01DOI: 10.2458/AZU_JRM_V56I4_JOSEPH
Jamus Joseph, J. Holechek, Raul Valdez, M. Collins, Milt G. Thomas
Scaled quail (Callipepla squamata) numbers were evaluated during and after a 2-year drought period using strip census techniques on 2 pastures in late seral rangeland ecological condition and 2 pastures in mid-seral rangeland ecological condtion. This study was conducted on the Chihuahuan Desert Rangeland Research Center (CDRRC) in south-central New Mexico on 4 adjoining pastures that were similar in size and terrain. During part of the study (August 1994 to April 1997) all 4 pastures were destocked due to depletion of perennial grass cover and biomass from a combination of drought and heavy cattle grazing. Scaled quail sightings pooled across sampling periods (9) were different (P = 0.08) on high and low rangeland ecological condition treatments. They averaged 10.72 birds per pasture on late-seral and 4.22 birds per pasture on mid-seral rangeland ecological condition treatments. Autumn perennial grass cover and standing biomass levels was higher (P 0.10) between treatments. Our study indicates that during extended dry periods livestock grazing at moderate intensities may adversely affect scaled quail populations in the Chihuahuan Desert by depleting perennial grass cover. However, in years of above average precipitation there is evidence scaled quail prefer mid-seral pastures over late-seral pastures. Maintaining a mosaic of conservatively (late-seral) and moderately (mid-seral) grazed pastures should best meet the habitat needs of scaled quail in the Chihuahuan Desert. DOI:10.2458/azu_jrm_v56i4_joseph
{"title":"Research observation: Effects of rangeland ecological condition on scaled quail sightings.","authors":"Jamus Joseph, J. Holechek, Raul Valdez, M. Collins, Milt G. Thomas","doi":"10.2458/AZU_JRM_V56I4_JOSEPH","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I4_JOSEPH","url":null,"abstract":"Scaled quail (Callipepla squamata) numbers were evaluated during and after a 2-year drought period using strip census techniques on 2 pastures in late seral rangeland ecological condition and 2 pastures in mid-seral rangeland ecological condtion. This study was conducted on the Chihuahuan Desert Rangeland Research Center (CDRRC) in south-central New Mexico on 4 adjoining pastures that were similar in size and terrain. During part of the study (August 1994 to April 1997) all 4 pastures were destocked due to depletion of perennial grass cover and biomass from a combination of drought and heavy cattle grazing. Scaled quail sightings pooled across sampling periods (9) were different (P = 0.08) on high and low rangeland ecological condition treatments. They averaged 10.72 birds per pasture on late-seral and 4.22 birds per pasture on mid-seral rangeland ecological condition treatments. Autumn perennial grass cover and standing biomass levels was higher (P 0.10) between treatments. Our study indicates that during extended dry periods livestock grazing at moderate intensities may adversely affect scaled quail populations in the Chihuahuan Desert by depleting perennial grass cover. However, in years of above average precipitation there is evidence scaled quail prefer mid-seral pastures over late-seral pastures. Maintaining a mosaic of conservatively (late-seral) and moderately (mid-seral) grazed pastures should best meet the habitat needs of scaled quail in the Chihuahuan Desert. DOI:10.2458/azu_jrm_v56i4_joseph","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83600595","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}
Prescribed burning has long been recognized as a useful tool in rangeland management, but with it comes the risk of fire and smoke damage to the property of others. All but 2 states have codified laws specifying criminal penalties or liability rules for prescribed burning, but the laws in a number of states have changed in recent years or are under review. We develop an economic model of the incentive and welfare effects of prescribed burning law and regulation in which the likelihood and extent of external damage can be reduced by precautionary effort on the part of both the burner and/or the victim. The model provides implications regarding the comparative advantages to the public of strict liability versus negligence rules. We conclude that the relative effectiveness of a liability rule depends in large part on the relative ability of burners and other landowners to mitigate the probability and extent of damage, as well as the legal costs associated with implementing a given liability rule.
{"title":"The economic logic of prescribed burning law and regulation","authors":"J. Yoder, D. Engle, M. Tilley, S. Fuhlendorf","doi":"10.2307/4004032","DOIUrl":"https://doi.org/10.2307/4004032","url":null,"abstract":"Prescribed burning has long been recognized as a useful tool in rangeland management, but with it comes the risk of fire and smoke damage to the property of others. All but 2 states have codified laws specifying criminal penalties or liability rules for prescribed burning, but the laws in a number of states have changed in recent years or are under review. We develop an economic model of the incentive and welfare effects of prescribed burning law and regulation in which the likelihood and extent of external damage can be reduced by precautionary effort on the part of both the burner and/or the victim. The model provides implications regarding the comparative advantages to the public of strict liability versus negligence rules. We conclude that the relative effectiveness of a liability rule depends in large part on the relative ability of burners and other landowners to mitigate the probability and extent of damage, as well as the legal costs associated with implementing a given liability rule.","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82546636","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}
Monitoring processes that affect plant population dynamics and determine community structure is central in forest restoration ecology. To study effects of mule deer (Odocoileus hemionus) and elk (Cervus elaphus) on buckbrush (Ceanothus fendleri Gray), we built exclosures around 90 plant-centered plots in 3 ponderosa pine (Pinus ponderosa Laws.) forest restoration management units and compared vegetative and flowering characteristics with unprotected plots for 2 years. On unprotected plots, 69% of the current-year branches were browsed during the first year and 44% were browsed the second year. There was no difference in number of aerial stems or current-year branches in the first year, yet stems on protected plots were longer (24.1 cm; P < 0.01) and retained more than 4 times the current-year biomass (1.4 g stem-1; P < 0.01) than those on unprotected plots (12.9 cm and 0.3 g stem-1, respectively). Stem number, length and diameter, number of current-year branches, and current-year biomass on protected plots were all greater (P < 0.01) than on unprotected plots in the second year. Stems on protected plots had significantly higher (P < 0.01) length-diameter ratios and had fewer current-year branches per unit length (P < 0.05) than unprotected stems. Flowering stems were found on significantly (P < 0.05) more protected plots (55%) than unprotected plots (8%) in the second year. Effects of ungulate herbivores on buckbrush size, stem recruitment, morphology, and flowering represent important constraints to early understory development and restoration in this Southwest ponderosa pine forest. DOI:10.2458/azu_jrm_v56i4_huffman
{"title":"Ungulate herbivory on buckbrush in an Arizona ponderosa pine forest","authors":"D. Huffman, M. M. Moore","doi":"10.2307/4004039","DOIUrl":"https://doi.org/10.2307/4004039","url":null,"abstract":"Monitoring processes that affect plant population dynamics and determine community structure is central in forest restoration ecology. To study effects of mule deer (Odocoileus hemionus) and elk (Cervus elaphus) on buckbrush (Ceanothus fendleri Gray), we built exclosures around 90 plant-centered plots in 3 ponderosa pine (Pinus ponderosa Laws.) forest restoration management units and compared vegetative and flowering characteristics with unprotected plots for 2 years. On unprotected plots, 69% of the current-year branches were browsed during the first year and 44% were browsed the second year. There was no difference in number of aerial stems or current-year branches in the first year, yet stems on protected plots were longer (24.1 cm; P < 0.01) and retained more than 4 times the current-year biomass (1.4 g stem-1; P < 0.01) than those on unprotected plots (12.9 cm and 0.3 g stem-1, respectively). Stem number, length and diameter, number of current-year branches, and current-year biomass on protected plots were all greater (P < 0.01) than on unprotected plots in the second year. Stems on protected plots had significantly higher (P < 0.01) length-diameter ratios and had fewer current-year branches per unit length (P < 0.05) than unprotected stems. Flowering stems were found on significantly (P < 0.05) more protected plots (55%) than unprotected plots (8%) in the second year. Effects of ungulate herbivores on buckbrush size, stem recruitment, morphology, and flowering represent important constraints to early understory development and restoration in this Southwest ponderosa pine forest. DOI:10.2458/azu_jrm_v56i4_huffman","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79990180","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 : 2003-07-01DOI: 10.2458/AZU_JRM_V56I4_PARSONS
Cory T Parsons, P. Momont, T. DelCurto, M. L. McInnis, Marni L. Porath
To quantify the effects of season of use on beef cattle distribution relative to the riparian area, 52 cow/calf pairs were used to evaluate 1) early summer grazing (mid-June to mid-July), and 2) late summer grazing (mid-August to mid-September) during the summers of 1998 and 1999. Within a block, cow/calf pairs used during early summer were also used during late summer grazing periods. Pastures were stocked to achieve 50% utilization of herbaceous vegetation after a 28-day grazing trial. Livestock location and ambient air temperature were recorded hourly during two, 4-day periods in each season of use. Locations were transcribed to a geographical information system for the study area. Ocular vegetation utilization estimates, forage quality, and fecal deposits within 1-m of the stream were recorded post-grazing. During early summer, cattle were further from the stream (P < 0.01) than late summer, averaging 161 and 99-m, respectively. Cows were observed closer (P < 0.01) to the stream when ambient air temperatures were higher. Fecal deposits within 1-m of the stream were similar (P = 0.13) following early and late summer grazing. Forage quality varied (P < 0.01) between seasons, with early summer forages having lower dry matter, greater crude protein, lower fiber, and greater in situ dry matter disappearance compared with late summer forages. Utilization of riparian vegetation was lower and use of upland vegetation greater during early summer than late summer (P < 0.05). In summary, season of use affected cattle distribution relative to the riparian area, with late summer pastures having more concentrated use of riparian vegetation. DOI:10.2458/azu_jrm_v56i4_parsons
{"title":"Cattle distribution patterns and vegetation use in mountain riparian areas.","authors":"Cory T Parsons, P. Momont, T. DelCurto, M. L. McInnis, Marni L. Porath","doi":"10.2458/AZU_JRM_V56I4_PARSONS","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I4_PARSONS","url":null,"abstract":"To quantify the effects of season of use on beef cattle distribution relative to the riparian area, 52 cow/calf pairs were used to evaluate 1) early summer grazing (mid-June to mid-July), and 2) late summer grazing (mid-August to mid-September) during the summers of 1998 and 1999. Within a block, cow/calf pairs used during early summer were also used during late summer grazing periods. Pastures were stocked to achieve 50% utilization of herbaceous vegetation after a 28-day grazing trial. Livestock location and ambient air temperature were recorded hourly during two, 4-day periods in each season of use. Locations were transcribed to a geographical information system for the study area. Ocular vegetation utilization estimates, forage quality, and fecal deposits within 1-m of the stream were recorded post-grazing. During early summer, cattle were further from the stream (P < 0.01) than late summer, averaging 161 and 99-m, respectively. Cows were observed closer (P < 0.01) to the stream when ambient air temperatures were higher. Fecal deposits within 1-m of the stream were similar (P = 0.13) following early and late summer grazing. Forage quality varied (P < 0.01) between seasons, with early summer forages having lower dry matter, greater crude protein, lower fiber, and greater in situ dry matter disappearance compared with late summer forages. Utilization of riparian vegetation was lower and use of upland vegetation greater during early summer than late summer (P < 0.05). In summary, season of use affected cattle distribution relative to the riparian area, with late summer pastures having more concentrated use of riparian vegetation. DOI:10.2458/azu_jrm_v56i4_parsons","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73717415","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 : 2003-07-01DOI: 10.2458/AZU_JRM_V56I4_FRANK
A. Frank, J. Karn
Native grasslands are a sink for atmospheric CO2 sequestration, but ways for extending site-specific CO2 flux measurements to a regional scale are lacking. Objectives of this study were to determine the utility of using canopy radiometric reflectance for estimating CO2 fluxes for semiarid grasslands. The relationship between the normalized difference vegetation index (NDVI) calculated from spectral reflectance data obtained with hand-held radiometers was compared to CO2 flux calculated from Bowen ratio/energy balance measurements. Carbon dioxide flux was measured during the plant growing season over a nongrazed prairie, grazed prairie, and a shrub dominated prairie site near Mandan, N.D. Measurements were also made of evapotranspiration (ET), green biomass, and green leaf area index (LAI). Correlation coefficients of NDVI with vegetation parameters of biomass and LAI for each site and year exceeded 0.84 in 1999, 0.74 in 2000, and 0.91 in 2001; with CO2 flux correlations exceeded 0.63 in 1999, 0.68 in 2000, and 0.69 in 2001; with ET correlations exceeded 0.91 in 1999, 0.92 in 2000, and 0.90 in 2001. Regression analysis over all years and sites produced a nonlinear relation between NDVI and both biomass (R2 = 0.83) and LAI (R2 = 0.77) and a linear relationship between NDVI and both CO2 flux (R2 = 0.51) and ET (R2 = 0.81). The relationships between NDVI and biomass, LAI, CO2 flux, and ET for the 3 grassland sites, which differed in management and vegetation, were generally quite similar suggesting that NDVI has potential for use in predicting canopy CO2 flux rates for semiarid grasslands in the Northern Great Plains. DOI:10.2458/azu_jrm_v56i4_frank
{"title":"Vegetation indices, CO2 flux, and biomass for Northern Plains grasslands.","authors":"A. Frank, J. Karn","doi":"10.2458/AZU_JRM_V56I4_FRANK","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I4_FRANK","url":null,"abstract":"Native grasslands are a sink for atmospheric CO2 sequestration, but ways for extending site-specific CO2 flux measurements to a regional scale are lacking. Objectives of this study were to determine the utility of using canopy radiometric reflectance for estimating CO2 fluxes for semiarid grasslands. The relationship between the normalized difference vegetation index (NDVI) calculated from spectral reflectance data obtained with hand-held radiometers was compared to CO2 flux calculated from Bowen ratio/energy balance measurements. Carbon dioxide flux was measured during the plant growing season over a nongrazed prairie, grazed prairie, and a shrub dominated prairie site near Mandan, N.D. Measurements were also made of evapotranspiration (ET), green biomass, and green leaf area index (LAI). Correlation coefficients of NDVI with vegetation parameters of biomass and LAI for each site and year exceeded 0.84 in 1999, 0.74 in 2000, and 0.91 in 2001; with CO2 flux correlations exceeded 0.63 in 1999, 0.68 in 2000, and 0.69 in 2001; with ET correlations exceeded 0.91 in 1999, 0.92 in 2000, and 0.90 in 2001. Regression analysis over all years and sites produced a nonlinear relation between NDVI and both biomass (R2 = 0.83) and LAI (R2 = 0.77) and a linear relationship between NDVI and both CO2 flux (R2 = 0.51) and ET (R2 = 0.81). The relationships between NDVI and biomass, LAI, CO2 flux, and ET for the 3 grassland sites, which differed in management and vegetation, were generally quite similar suggesting that NDVI has potential for use in predicting canopy CO2 flux rates for semiarid grasslands in the Northern Great Plains. DOI:10.2458/azu_jrm_v56i4_frank","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83757033","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 : 2003-07-01DOI: 10.2458/AZU_JRM_V56I4_FUCHS
Erek H. Fuchs, M. Wood, T. M. Jones, B. Racher
Off-road military vehicle traffic is a major consideration in the management of military lands. The objective of this study was to determine the impacts of military tracked M1A1 heavy combat tank vehicles on sediment loss from runoff, surface plant cover, and surface microtopography in a desert military training environment. A randomized block design was used which had 10 blocks with 4 plots (0.5 m2) in each block. Each block had randomly selected treatments that included an untreated control, 1 pass by a M1A1 tank under wet seasonal conditions, 3 passes by a M1A1 tank under wet seasonal conditions, 1 pass by a M1A1 tank under dry seasonal conditions, and 3 passes by a M1A1 tank under dry seasonal conditions. Data were analyzed using mean separation and stepwise regression techniques. Most sample periods showed that sediment losses from M1A1 tank treatments, single or triple passes under wet or dry seasonal conditions, did not differ statistically from natural sediment losses under nominal rainfall events. However, comparatively intense rainfall events often generated significantly (P < 0.05) greater sediment losses from the M1A1 tank triple pass treatments. Triple pass M1A1 tank impacts had detrimental effects that could last many years, particularly when disturbances were imposed under dry seasonal conditions. Seasonal drought for the area, occurring 2 out of 3 years during the study period, may have exacerbated the effects of triple pass M1A1 tank impacts. Analysis showed that grass cover, litter cover, and microtopographic variance were highly and negatively correlated (R = -0.62) with cumulative sediment loss. Depending on precipitation availability, a minimum of 3 years for most triple pass M1A1 tank impacts is suggested for suitable vegetation recovery and soil stability. It is recommended that site repetitious M1A1 tank training maneuvers should be conducted with particular attention to site recovery. Furthermore, the influence of climate, drought in particular, should be among the topics addressed by future military training land use models. DOI:10.2458/azu_jrm_v56i4_fuchs
{"title":"Impacts of tracked vehicles on sediment from a desert soil","authors":"Erek H. Fuchs, M. Wood, T. M. Jones, B. Racher","doi":"10.2458/AZU_JRM_V56I4_FUCHS","DOIUrl":"https://doi.org/10.2458/AZU_JRM_V56I4_FUCHS","url":null,"abstract":"Off-road military vehicle traffic is a major consideration in the management of military lands. The objective of this study was to determine the impacts of military tracked M1A1 heavy combat tank vehicles on sediment loss from runoff, surface plant cover, and surface microtopography in a desert military training environment. A randomized block design was used which had 10 blocks with 4 plots (0.5 m2) in each block. Each block had randomly selected treatments that included an untreated control, 1 pass by a M1A1 tank under wet seasonal conditions, 3 passes by a M1A1 tank under wet seasonal conditions, 1 pass by a M1A1 tank under dry seasonal conditions, and 3 passes by a M1A1 tank under dry seasonal conditions. Data were analyzed using mean separation and stepwise regression techniques. Most sample periods showed that sediment losses from M1A1 tank treatments, single or triple passes under wet or dry seasonal conditions, did not differ statistically from natural sediment losses under nominal rainfall events. However, comparatively intense rainfall events often generated significantly (P < 0.05) greater sediment losses from the M1A1 tank triple pass treatments. Triple pass M1A1 tank impacts had detrimental effects that could last many years, particularly when disturbances were imposed under dry seasonal conditions. Seasonal drought for the area, occurring 2 out of 3 years during the study period, may have exacerbated the effects of triple pass M1A1 tank impacts. Analysis showed that grass cover, litter cover, and microtopographic variance were highly and negatively correlated (R = -0.62) with cumulative sediment loss. Depending on precipitation availability, a minimum of 3 years for most triple pass M1A1 tank impacts is suggested for suitable vegetation recovery and soil stability. It is recommended that site repetitious M1A1 tank training maneuvers should be conducted with particular attention to site recovery. Furthermore, the influence of climate, drought in particular, should be among the topics addressed by future military training land use models. DOI:10.2458/azu_jrm_v56i4_fuchs","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72725058","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}
Wildfires commonly occur in the Fescue Prairie of Alberta, but little information exists to provide a basis for making grazing recommendations after burning. A wildfire in April 1999 provided an opportunity to study the effect of season and intensity of post-burn defoliation on foothills rough fescue (F. campestris Rydb.) in southwestern Alberta. A 3 (date of defoliation) x 2 (defoliation intensity) factorial experiment with 10 replicates (plants) was established in both a burned and a non-burned grassland and analyzed as a nested design. Plants were defoliated once during active vegetative growth (17 May), inflorescence development (2 July), or dormancy (30 September), at either 5 or 15-cm clipped stubble heights in the first growing season after fire. Burning increased tiller numbers by 54% compared to non-burned plants but reduced plant ANPP by 51% in the second growing season. While a single defoliation of burned plants, particularly early in the year, had little effect on growth, delaying defoliation into July decreased tillers 1 year later. Increasing defoliation intensity had the greatest impact on non-burned plants, reducing plant height (15%) as well as tiller (21%) and plant (32%) ANPP in the second year. May defoliation reduced etiolated growth 1 year later regardless of burn treatment. A single grazing event after wildfire does not necessarily appear to detrimentally affect rough fescue; however, the low herbage available immediately after fire may not justify the increased risk to the plant with subsequent grazing. DOI:10.2458/azu_jrm_v56i4_bogen
{"title":"Defoliation impacts on Festuca campestris (Rydb.) plants exposed to wildfire","authors":"A. D. Bogen, E. Bork, W. Willms","doi":"10.2307/4004042","DOIUrl":"https://doi.org/10.2307/4004042","url":null,"abstract":"Wildfires commonly occur in the Fescue Prairie of Alberta, but little information exists to provide a basis for making grazing recommendations after burning. A wildfire in April 1999 provided an opportunity to study the effect of season and intensity of post-burn defoliation on foothills rough fescue (F. campestris Rydb.) in southwestern Alberta. A 3 (date of defoliation) x 2 (defoliation intensity) factorial experiment with 10 replicates (plants) was established in both a burned and a non-burned grassland and analyzed as a nested design. Plants were defoliated once during active vegetative growth (17 May), inflorescence development (2 July), or dormancy (30 September), at either 5 or 15-cm clipped stubble heights in the first growing season after fire. Burning increased tiller numbers by 54% compared to non-burned plants but reduced plant ANPP by 51% in the second growing season. While a single defoliation of burned plants, particularly early in the year, had little effect on growth, delaying defoliation into July decreased tillers 1 year later. Increasing defoliation intensity had the greatest impact on non-burned plants, reducing plant height (15%) as well as tiller (21%) and plant (32%) ANPP in the second year. May defoliation reduced etiolated growth 1 year later regardless of burn treatment. A single grazing event after wildfire does not necessarily appear to detrimentally affect rough fescue; however, the low herbage available immediately after fire may not justify the increased risk to the plant with subsequent grazing. DOI:10.2458/azu_jrm_v56i4_bogen","PeriodicalId":16918,"journal":{"name":"Journal of Range Management","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73251679","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}
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