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An analysis of land ownership and range management practices in the northern Kansas Flint HillsWilds, Stanley R. January 1986 (has links)
Call number: LD2668 .T4 1986 W542 / Master of Arts / Geography
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Ecology and Management of a High Elevation Southern Range Greater Sage-Grouse Population: Vegetation Manipulation, Early Chick Survival, and Hunter MotivationsGuttery, Michael R. 01 December 2010 (has links)
My research provided new information concerning the management, ecology, and conservation of greater sage-grouse (Centrocercus urophasianus). I report the results of an experiment using strategic intensive sheep grazing to enhance the quality of greater sage-grouse brood-rearing habitat. Although forb cover, an important component of brood-rearing habitat, responded positively to the grazing treatment, the response of other habitat variables was suppressed because the plots were not protected from domestic and wild herbivores during the years following the treatments. Measurements taken in grazing exclosures confirmed that herbivory by both large and small animals had significant impacts on vegetation. However, despite the suppressed habitat response, sage-grouse preferred the treated plots over the controls. In another chapter, I modeled survival rates of sage-grouse chicks to 42-days of age. Average chick survival across my study was high (39%). Survival varied across years and was affected by demographic, behavioral, and habitat factors. The top habitat model indicated that chick survival was positively related to grass cover and was higher in areas dominated by black sagebrush (Artemisia nova) than in big sagebrush (A. tridentata). The top model with demographic/behavioral factors indicated that survival was affected by interactions between hen age and brood mixing as well as between hatch date and brood mixing. In my last chapter I report on a survey of Utah sage-grouse hunter motivations and satisfaction. In 2008 and 2009 I surveyed over 600 sage-grouse hunters in Utah to determine why they chose to apply for sage-grouse hunting permits and what factors contributed to a satisfactory hunting experience. Originally, I had hypothesized that the impending Endangered Species Act listing petition for greater sage-grouse motivated hunters to pursue the species before they lost the opportunity. This hypothesis was not supported by the data. The majority of hunters indicated that they chose to hunt sage-grouse because it was a tradition or because it provided an opportunity to spend time outdoors with family. Additionally, Utah sage-grouse hunter satisfaction was influenced by whether or not the hunter was successful in harvesting at least one bird.
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Greater Sage-Grouse Seasonal Ecology and Responses to Habitat Manipulations in Northern, UtahThacker, Eric T. 01 May 2010 (has links)
Declining greater sage-grouse populations (Centrocercus urophasianus; hereafter sage-grouse) have led to increased concern regarding the long-term stability of the species. Previous research has identified factors contributing to the observed population declines. Habitat degradation and loss have been implicated as major factors in population declines. Although much is known about sage-grouse biology, more information is needed about population responses to specific management actions. This research was conducted to document sage-grouse responses to site-specific management actions. Additionally, I evaluated sage-grouse temporal and seasonal habitat-use and the comparability of techniques used by range and wildlife managers to measure vegetation responses of habitat management. Specifically, I evaluated 1) whether chemical analysis (gas chromatography) of sage-grouse fecal pellets could identify sagebrush species in sage-grouse winter diets, 2) the comparability of the line-point intercept and Daubenmire canopy cover methods for estimating canopy cover, 3) the response of sage-grouse broods to prescribed burns in a high elevation sagebrush community in northeastern Utah, and 4) the vegetation and insect characteristics of sites used by sage-grouse broods during a 24-hour period. I was able to determine wintering sage-grouse diets using gas chromatography by analyzing fecal pellets. This research also confirmed that black sagebrush (Artemisia nova) was an important component of sage-grouse winter diets in western Box Elder County and Parker Mountain populations. The line-point intercept and Daubenmire methods for estimating canopy cover are not comparable. Sage-grouse broods selected small (~ 25 ha) patchy prescribed burns in high elevation mountain big sagebrush (A. tridentata vaseyana) communities in northeastern Utah. Sage-grouse brood-site use in northwestern Utah did not differ during the diurnal hours, but nocturnal roost sites were characterized by shorter statured shrubs and more bare ground when compared to midday sites.
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Vegetation Characteristics of Wyoming Big Sagebrush Communities Historically Seeded with Crested Wheatgrass in Northeastern Great Basin, USAWilliams, Justin Rodney 01 May 2009 (has links)
Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) is one of the most commonly seeded grass species in the western United States and dominates thousands of hectares in the Great Basin. Although many degraded Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) plant communities have been seeded with crested wheatgrass, successional pathways, influence of soil attributes, and cultivation history on the vegetation of these communities have not been fully characterized. I sought to identify community phases, vegetative differences, and soil attributes that explain variation among 35 Wyoming big sagebrush communities historically seeded with crested wheatgrass. All communities were more than 30 years old and had not experienced fire, or received subsequent chemical or mechanical treatments following their original seeding. Species richness, diversity, vegetation cover, and soil samples were measured in four 20 x 5 m intensive Modified Whittaker plots per community. Hierarchical clustering and principal component analysis of three indicator species (crested wheatgrass, Sandberg bluegrass, and Wyoming big sagebrush) identified four distinct community phases. Community phase 1 was dominated by crested wheatgrass and had the lowest species richness and cover of big sagebrush. Phases 2 and 3 had the highest species richness and cover of native species. Phase 4 was dominated by big sagebrush and had the lowest cover of crested wheatgrass. Community phases differed significantly for soil texture, soil nitrogen, and ground cover characteristics. Bare soil was almost double on loam-textured soils and rock cover was higher on clay loam texture soils (P < 0.05) as well as native plant cover. Communities previously cropped occurred on more coarse-textured soils and had 6-fold lower native species cover and double exotic herbaceous and crested wheatgrass cover. Cropping occurred on favorable, low rock, fine-texture soils, the same soils that favor crested wheatgrass production and reduce resilience of native plant composition. Delineation of community phases provided a new, empirically based state-and-transition model, while the characterization of soil attributes and disturbance history provided information about feedback mechanisms influencing dominant species that delineate community phases and effect community structure. This information can be used to assist in the development of management strategies in crested wheatgrass seeded communities.
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A strategy for optimal beef production off sourveld.Buntting, Clive Bartle. 06 December 2013 (has links)
The economic necessity of a better production strategy on sourveld promoted this study. Production of marketable two-tooth steers in the summer season and overwintering of all cattle without excessive feed costs were motivating factors. The problems of economic beef production were identified as resulting from the seasonal flow of forage quality from
sourveld grass production. Season long rests, early burning and non-selective grazing of nutritious grass were identified as essential elements of a new utilization strategy. A 'forage reserve', built into the system to cater for fluctuations in grass production due to varied climatic conditions, is used as an indicator of the seasonal stocking rate. This
provides a barometer in relation to the economic and ecological carrying capacity of the property. Research was conducted on the winter utilization of rested veld and its effects on grass species composition and vigour in the following season. It was found that the winter grazing of the rested veld did not affect (P>0.05) the subsequent production in the three
seasons of this study on 'Stratherne' in the Dundee district, KwaZulu-Natal South Africa (30°17'E 28°17'S). The grass species composition of four transects was recorded in 1994, prior to the implementation of the grazing system under test. The same transects were recorded again in 2002 to determine the effect of the change in utilization on grass species composition. It was found that a more productive state was developing in response to the strategy implemented in this study. The general trend has been for sites to move from a Hyparrhenia hirta dominated state to a more productive one associated with species such as Themeda triandra. Summer mass gains of steers (147 kg and 143 kg over the two summers) have improved over the previous systems applied (average 119 kg), as a result of the more nutritious grazing. A greater proportion reached market readiness as two-year old to two and half year olds (97%) on veld, which is far superior to the 38% quoted from research using similar Bonsmara type steers from 'conventional' systems. Monitoring and flexibility are
important in the application of the strategy to conditions in Africa. The principles of adaptive management (monitoring, recording, constant learning and adaptation) will build a data base to ensure long-term success of the strategy. A change of focus in grazing strategy from needs of animals to the needs of plants is strongly advocated. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
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The effects of burning and mowing on microclimate and soil resources and implications for species change in the southern tall grassveld of KwaZulu-Natal.Ghebrehiwot, Habteab Mesghina. 10 December 2013 (has links)
Promotion of a predictive understanding of plant community response to various forms,
frequencies and seasons of disturbance, either through the direct physical effect on biota and
or indirect effect on plants, through modification of microclimate and soil attributes is
currently a major goal in plant ecology. In particular, the effect of disturbance on altering the
ratio between available light and nutrients and their resultant effect on growth, shoot/root
allocation, and thus community composition has gained considerable recognition in
connection with the mechanisms of plant succession under a popular heading "the resource
ratio hypothesis of plant succession". Contemporary and long-term (>50 years) burning and
mowing experiments in KwaZulu-Natal (KZN) provide important sites for investigation that
in the mesic grasslands of KZN, community composition changes in response to the
frequency, time and type of disturbances such as burning, mowing and veld fertilization.
However, the relationship between disturbance-resource-plant traits and their interactive role
in species change is virtually unknown. This study sought to improve understanding of mesic
grassland dynamics in. KZN, using short-term pot and plot experiments. The principal
objectives were: 1) by subjecting plants to different levels of resources viz. light, nutrients,
water and cutting to determine the relative above and below-ground growth performances
(biomass allocation) of species from contrasting habitat preference in KZN, which implies
their relative competitive ability for limiting resources and tolerance to cutting, 2) by using a
short-term (one-season period) burning and mowing experiment to determine the effect of
different veld management practices on microclimate and availability of soil resources and
their subsequent effect on plant growth performances, 3) testing the relative shade tolerance of
representative species from contrasting habitat preferences, 4) by combining the outcomes
from these experiments, to provide a general synthesis concerning species' response to
disturbance/resource which further signifies species change.
The hypothesis that competitive ability as a function of biomass allocation is fertility
dependent was supported by a pot experiment. In low nutrient treatments short grass species
that predominate infertile soils in KZN viz. Aristida funcifarmis and Themeda triandra
attained double the shoot biomass, more than double root biomass, initiated more tillers and re-grew better (after cutting) than those inherently tall species that predominate fertile sites
viz. Eragrostis curvula and Hyparrhenia hirta. In contrast, in high nutrient treatments, tall
species attained far higher shoot biomass and grew taller in height. Interestingly, short species
had a smaller shoot: root ratio than tall species, consistent with the prediction of the resource
ratio hypothesis. However, no evidence was obtained suggesting that tall species were more
shade tolerant than short species. A field-based shade experiment rather showed that, those
species that initiate tillers below-ground viz. Aristida junciformis, Eragrostis curvula and
Tristachya leucothrix were more shade tolerant than those species that initiate tillers above-ground
viz. Hyparrhenia hirta and Themeda triandra.
On the other hand, the effect of disturbance/resource relationship in influencing the
growth (biomass production, growth rate, and basal circumference) of contrasting species was
examined by conducting a short-term (one season) burning and mowing experiment. The
effect of disturbance, its form and frequency through its effect on light and soil moisture was
able to account for a substantial difference in species vigour, which can potentially impact
community composition. Short species (Themeda triandra and Tristachya leucothrix) showed
their highest biomass production and higher basal circumference enlargement in burnt summer
mown sites, whereas medium to tall species (Aristida junciformis, Eragrostis curvula and
Hyparrhenia hirta) were less tolerant to summer mowing. Aristidajunciformis and Eragrostis
curvula appeared to be more vigorous (both in terms of above-ground biomass production and
growth rate) in burnt but not mown and control treatment respectively. High biomass and litter
accumulation on sites protected from disturbance appeared to have a large influence on
species vigour. Species such as Aristida junciformis, Eragrostis curvula and Tristachya
leucothrix had high tolerance to litter accumulation while in contrast Hyparrhenia hirta and
Themeda triandra were more vulnerable. In total this study has revealed that the association of
some short species e.g. Themeda triandra with the reccurrence of disturbance is mainly due to
increases in light availability and lowered dominance from tall species in frequently disturbed
sites rather than nutrient related. However, this study has revealed that there are some
indications whereby the notion that the inverse relationship between available light and
nitrogen are important driving variables in species change is an important working theory in the mesic grassveld of KZN. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.
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Studies of the management of grazing resources on the Makatini Flats and Pongolo River Floodplain.Buchan, Alastair James Charles. January 1988 (has links)
Subsequent to the impounding of the Pongolo river in the 1970's, development
of irrigated agriculture on the Makatini flats has been reducing the area of
vegetation available for grazing, and flooding patterns on the seasonally
inundated Pongolo River Floodplain have been determined by the controlled
release of water from the Pongolapoort dam. About 50 000 people live along
the 10 000 ha floodplain within the 63 000 ha northern region of the flats
which was studied. This population includes 2 970 registered cattle owners who
own a total of 19 300 cattle.
The objectives of this study were: to gain an understanding of the Makatini
pastoral system which would facilitate prediction of the effects of potential
developments, including agricultural expansion, modification of floodplain
hydrology and changed cattle management practices on the utility value of
cattle; and to provide guidelines for the management of pastoral resources on
the Makatini and other traditional African pastoral systems.
It was established that the value of cattle cannot be determined without
understanding the importance of the subsistence utilities provided and that
the value of utilities relative to each other influences the way in which the
system is stocked and managed by the local people. The value of all marketed
and non-marketed utilities was determined and the implications of the economic
evaluation for the identification of management options in African pastoral
systems assessed. Despite the "low productivity" of the Makatini system
compared to western style ranches, cattle owners receive annual returns worth
approximately 100 % of the asset value of their stock. This explains low
market offtake rate in this and other subsistence systems. Non-marketed
utilities, particularly milk production provide most of the returns to cattle
owners.
The mean stocking density on the floodplain vegetation was estimated to be
three times that of dry-land areas, but only 23 % of all grazing time is spent
on the floodplain. Although floodplain forage provides an important
supplement to winter grazing, its use is not vital to maintenance of animal
condition. The coincident occurrence of an annual "stress period"; greater
acceptability of Echinochloa pyramidalis vegetation as forage; the absence of
floods; and the reduced use of floodplain fields, results in increased
floodplain use in winter to a stocking density approximately ten times that of
dry-land areas.
How the floodplain hydrology, rainfall and grazing interact with the crop
growth rate and quality of E. pyramidalis stands was examined. The forage
production potential of E. pyramidalis was found to be higher than that of
other floodplain vegetation types and stocking densities of up to 4.5 AU/ha in
summer and 2.5 AU/ha in winter are considered possible on the Pongolo
floodplain. Echinochloa pastures may become wet and cause scouring if grazed
exclusively, but grazing reduces plant moisture content and makes the forage
more acceptable.
Local pastoral management was found to depend on the collective activities of
cattle owners in pursuit of personal needs in a dynamic socio-economic
context. Motivation for the manipulation of cattle numbers and herd
composition is dictated by a cattle owner's perception of his needs for
utilities and his ability to access those benefits. Because of this, the
pastoral practices were found to be closely linked to other socio-economic
activities such as agriculture and migrant labour. stock owners have a narrow
perspective of pastoral resource management and use strategies developed on
small spatial and temporal scales.
In contrast development planners tend to identify objectives on a regional
scale and on long-term (10 - 50 year) time scales and to orient management
towards maximising the value of marketable utilities and preventing long-term
overstocking. Management of pastoral resources in traditional African systems
requires that the needs of local people be met, that the resource base be
maintained; that pastoral policy be developed as a component of regional
development planning and that close liaison between interest groups be
maintained. Failure to establish or maintain this liaison is considered the
main reason for the failure of many African pastoral development programmes.
It was recommended that local pasture management committees be established on
the Makatini and that extension officers, trained specifically to understand
management problems of Third World pastoral systems, be used to maintain
liaison between stock owners and development planners. It was also suggested
that formal cattle camps be established and managed by local people and that
at least one flood (river flow> 200 cumecs) be released from the Pongolapoort
darn each summer. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1988.
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The bioeconomic implications of various stocking strategies in the semi- arid savanna of Natal.Hatch, Grant Peter. January 1994 (has links)
Climatic and market uncertainty present major challenges to livestock producers
in arid and semi-arid environments. Range managers require detailed information
on biological and economic components of the system in order to formulate
stocking strategies which maximise short-term financial risk and minimise long-term
ecological risk. Computer-based simulation models may provide useful tools to
assist in this decision process. This thesis outlines the development of a
bioeconomic stocking model for the semi-arid savanna of Natal.
Grazing trials were established at two sites (Llanwarne and Dordrecht) on
Llanwarne Estates in the Magudu area of the semi-arid savanna or Lowveld of
Natal. The Lowveld comprises a herbaceous layer dominated by Themeda triandra,
Panicum maximum and P. coloratum and a woody layer characterised by Acacia
species. The sites differed initially in range composition. Llanwarne was
dominated by Themeda triandra, Panicum maximum and P. coloratum, while
Dordrecht with a history of heavy stocking was dominated by Urochloa
mosambicensis, Sporobolus nitens and S. iocladus. Three treatments were stocked
with Brahman-cross cattle at each site to initially represent 'light'(0.17 LSU ha-'),
'intermediate' (0.23 LSU ha-') and 'heavy' (0.30 LSU ha-') stocking. Data collected
at three-week intervals over seven seasons (November 1986 to June 1993 or 120
measuring periods) provided the basis for the development of a bioeconomic
stocking model (LOWBEEF - LOWveid BioEconomic Efficiency Forecasting) which
comprised two biological sub-models (GRASS and BEEF), based on step-wise
multiple linear regression models, and an integrated economic component (ECON) .
The GRASS model predicted the amount of residual herbage at the end of summer
(kg ha-') and the forage deficit period (days) over which forage supplementation
would be required to maintain animal mass. Residual herbage mass at the end of
summer (kg ha-') was significantly related (P < 0.01) to cumulative summer grazing
days (LSU gd ha-'), rainfall (mm) (measured 1 July to 30 June) and range condition
(indexed as the sum of the proportions of T. triandra, P. maximum and P.
coloratum). The forage deficit period (days) over which herbage mass declined
below a grazing cut-off of 1695 kg ha-' was significantly related (P < 0.01) to residual herbage mass at the end of summer. The BEEF model predicted the
livemass gain over summer (kg ha¯¹)
which was significantly related (P< 0.01)
to rainfall (mm) stocking rate (LSU ha¯¹) but interestingly not to
condition. The economic component (ECON) reflected the difference between
gross income (R ha¯¹) and total costs, which were based on fixed and variable cost
structures (using 1993 Rands), including demand-related winter costs, to
reflect net returns to land management (R ha¯¹).
A conceptual model of range dynamics based on three discrete states, was
to developed to summarise the effects of rainfall and stocking rate in semi-arid
savanna. State 1, characterised by iocladus and S. nitens, was associated with
heavy stocking. Movement towards State 2, characterised by T. triandra and
P. maximum, was associated with periods of above-average rainfall. Drought
conditions, which comprised a major system disturbance led to stability at State 3,
dominated by U. mosambicensis. Post-drought recovery was influenced by predrought
composition and stocking levels where tuft numbers, basal cover and seedbank
were significantly reduced by increased stocking within a sward
dominated by species of low stature such as Aristida congesta subsp
Urochloa mosambicensis, Sporobolus nitens, Sporobolus iocladus and Tragus
racemosa. It was suggested that extensive soil loss may lead to stabilisation
across an irreversible threshold at a forth state characterised by shallow
species such as Tragus racemosa Aristida congesta subsp. congesta.
Sensitivity of optimum economic stocking rate net return to price and interest
rate fluctuations, and wage and feed cost increases were examined for various
rainfall and range condition scenarios. Net return and optimum economic stocking
rate increased as rainfall and range condition increased through the effect of increased
residual herbage mass at the end summer, decreased forage deficit
periods and reduced supplementary feed costs. Net return was highly responsive
to changes beef price where an increase in beef price led to an increase in
optimum economic stocking rate and net return. The effect of reduced prices may
be compounded by dry where supply-driven decreases in price may occur. This suggested that for dry seasons the optimum stocking rate was the lightest
within the range of economic stocking rates. Although an increase in interest rates
would increase variable costs and lead to reduced returns, the influence of interest
rates on enterprises will vary in relation to farm debt loads. Increased labour costs
would result in a corresponding decline in net return although optimum economic
stocking rate would remain unaffected. Increased supplementary feed cost had
little influence on net return relative to the effect of demand-driven increases in
feed costs as rainfall decreased .
The distribution of net returns for stocking strategies of 0.20, 0.30 and 0.40 LSU
ha¯¹ and climate-dependent stocking (where stocking levels were varied in relation
to rainfall and hence forage availability) and range condition scores of 10, 50, 80
and a dynamic range model were examined for a 60 year rainfall sequence (1931-
1991). While a range score of 10 would see residual herbage mass decline to
below a grazing cut-off of 1695 kg ha¯¹ before the end of summer, a range score
of 80 suggested that, irrespective of stocking strategy within the range
investigated, herbage would not become limiting. This suggested that irrespective
of stocking strategy a range score of 10, established across an irreversible soil loss
threshold, would reflect accumulated losses over the 60 year period. In contrast,
a range score of 80 would lead to positive accumulated returns. A dynamic range
model (where range composition was related to previous seasons rainfall) and a
climate-dependent stocking strategy, suggested that herbage would not become
limiting by the end of summer and forage deficit periods would be restricted to an
average of 88 days per year. Such an approach would yield a higher accumulated
cash surplus than fixed stocking strategies.
Incorporation of stochastic rainfall effects allowed the development of cumulative
probability distributions based on 800-year simulations to evaluate the risk
associated with various stocking strategies. Range condition played a major role
in determining the risk of financial loss where decreased range condition was
associated with enhanced risk. An increase in stocking rate resulted in increased
variability in returns. Although the risk of forage deficits and financial losses may be reduced with lighter stocking, this may be at the cost of reduced returns during
wetter seasons. Increased stocking may increase the probability of higher returns
during wetter seasons although this may at the cost of increased risk of forage
deficits and highly negative returns during dry seasons. Importantly, ecological risk
may increase as stocking is increased. A flexible or climate-dependent strategy,
where stock numbers are adjusted according to previous seasons rainfall,
combine financial benefits of each approach and reduce financial risk.
Although errors may carry hig h ecological costs where, for example, the effect of
an above-average rainfall season would be to increase stock numbers into a
subsequent dry season, the probability of incurring such error was low.
Current livestock production systems in the semi-arid savanna of Natal based on
breeding stock may not be appropriate in a highly variable environment where low
rainfall may require extended periods of supplementary feeding or force the sale of
breeding stock. A change in emphasis from current systems to a mixed breeding
system, where the level of breeding stock would be set at the optimum economic
stocking rate for drier seasons, may decrease both financial and ecological risk.
Growing stock may either be retained or purchased during wetter seasons to reach
the optimum economic stocking rate for such seasons. Although growing stock
may display a greater tolerance to restricted intake (during dry seasons)
than would breeding stock, additional growing may be rapidly sold in
response to declining rainfall with no influence on the breeding system. Integration
of wildlife into current cattle systems may be an important means of reducing
financial risk associated with variable rainfall and profitability and ecological risk
associated with woody plant encroachment. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1994.
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Nature management by grazing and cutting on the ecological significance of grazing and cutting regimes applied to restore former species-rich grassland communities in the Netherlands.Bakker, Jan Pouwel. January 1989 (has links)
Thesis (doctoral)--Rijksuniversiteit te Groningen, 1989. / Includes bibliographical references (p).
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Influence of previous cattle and elk grazing on the subsequent diet quality and nutrient intake rate of cattle, deer, and elk grazing late-summer mixed-conifer rangelands /Damiran, Daalkhaijav. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references. Also available on the World Wide Web.
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