Cattle Access Research Articles

Phytoplankton patterns along a series of small man-made reservoirs in Kenya

We studied nine small man-made reservoirs located in different climate regions of Kenya to get an insight into the relationship between phytoplankton community structure and its environment. The investigated ponds form three groups of three reservoirs each found in the rural areas of Machakos district, Mount Kenya region, and Lake Victoria area with varied climatic characteristics. The ponds were sampled in monthly intervals between May 2007 and June 2008 for physicochemical variables including water chemistry, phytoplankton community composition, zooplankton abundance, and bacterial numbers. All ponds were classified as hypertrophic. Seasonal changes were reflected in the phytoplankton pattern, as all ponds showed a community shift after the short dry season in February. Due to high nutrient loads and increased turbidity, Cyanobacteria, which were initially thought to be predominating in all investigated water bodies, were found to play only a minor role except for the Bomet reservoir in Lake Victoria region. Instead, Chloro- and Streptophyta, Dinophyta, and Euglenophyta were abundant in the pelagial. A principal component analysis explained around 85% of the data variance with four principal components (PCs) interpreted as "location", "ions", "zooplankton", and "particulate matter". A clear separation of ponds with and without cattle access based on algal species community data was found indicating the need for a sustainable use and regular monitoring program as the local population is largely dependent on these sensitive small-scale ecosystems.

A study of cattle producer preferences for best management practices in an East Tennessee watershed

Best Management Practices (BMPs) contribute to a broader range of efforts to improve the environmental performance of the livestock sector and its impact on water quality. This research evaluates a survey of cattle producers in an East Tennessee watershed and parts of five surrounding watersheds, along with and the factors correlated with preferences for BMPs designed to reduce sediment, nutrient, and fecal coliform contamination of surface waters by limiting cattle access to streams. The objective of the survey was to gather behavioral information about producer interest in specific BMPs in an effort to supplement a long-term biophysical modeling project. Structures and BMPs analyzed include stream crossings, rotational grazing, pasture improvement, and cattle water tanks. The physical and economic constraints faced by producers and the incentives provided by state and federal programs influence the decision to adopt a set of practices or structures that impact pathogen loading into streams. There was a clear preference for a suite of BMPs that did not include stream crossings, reinforcing anecdotal evidence that the maintenance associated with frequent high flow events may reduce willingness to install stream crossings. Cattle producers were more willing to implement rotational grazing and pasture improvement BMPs, which were associated with cattle health and productivity. The extensive distribution of pastureland in the region analyzed, the relatively inexpensive costs of adopting practices supporting pasture improvement, and higher quality forage correlated with improved pastures suggest a win-win outcome for cattle owners and efforts to enhance water quality.

Transplanting native tree seedlings to enrich tropical live fences: an ecological and socio-economic analysis

The enrichment of live fences with native tree species has been proposed as a conservation strategy in agricultural landscapes; however, little research has explored ways to do this in tropical areas. This study examines selection of native tree species, effects of damage caused by mammals (mainly cattle) in performance (survival and growth) of transplanted seedlings, and cost-benefit balances as critical steps to enrich tropical live fences. Seven native tree species, with ecological and socio-economic importance, were selected in a Mexican agricultural landscape to grow as seedlings, and six of them were transplanted into live fences of cattle ranches with different levels of cattle activity (none/moderate/high). Costs associated with propagation and seedling protection in the field were calculated, and performance and damage in seedlings were measured over 2 years. We developed an index to identify species with the best performance and lowest costs in sites with cattle activity. Our results showed that damage, caused mainly by cattle, reduced the performance of transplanted seedlings. The effect of this damage varied depending on its severity (level and frequency) and the identity and life history of species. All selected species performed well in the site without cattle access. Dendropanax arboreus was the best species at site with moderate cattle activity, and Trema micrantha and Saurauia scabrida at site with high cattle activity. These species are recommended for enriching live fences because of good cost-benefit balance. This approach could be an important quantitative method to select species useful not only in agroforestry but also in restoration projects, which normally remain under the pressure of domestic and wild animals.

Coherence among Different Microbial Source Tracking Markers in a Small Agricultural Stream with or without Livestock Exclusion Practices

Over 1,400 water samples were collected biweekly over 6 years from an intermittent stream protected and unprotected from pasturing cattle. The samples were monitored for host-specific Bacteroidales markers, Cryptosporidium species/genotypes, viruses and coliphages associated with humans or animals, and bacterial zoonotic pathogens. Ruminant Bacteroidales markers did not increase within the restricted cattle access reach of the stream, whereas the ruminant Bacteroidales marker increased significantly in the unrestricted cattle access reach. Human Bacteroidales markers significantly increased downstream of homes where septic issues were documented. Wildlife Bacteroidales markers were detected downstream of the cattle exclusion practice where stream and riparian habitat was protected, but detections decreased after the unrestricted pasture, where the stream and riparian zone was unprotected from livestock. Detection of a large number of human viruses was shown to increase downstream of homes, and similar trends were observed for the human Bacteroidales marker. There was considerable interplay among biomarkers with stream flow, season, and the cattle exclusion practices. There were no to very weak associations with Bacteroidales markers and bacterial, viral, and parasitic pathogens. Overall, discrete sample-by-sample coherence among the different microbial source tracking markers that expressed a similar microbial source was minimal, but spatial trends were physically meaningful in terms of land use (e.g., beneficial management practice) effects on sources of fecal pollution.

Habitat selection by cattle in Foothill landscapes following variable harvest of aspen forest

Logging of aspen (Populus tremuloides Michx.) forests on public grazing land in west central Alberta creates a mosaic of habitat types that may alter cattle (Bos taurus) use of these landscapes. We used an extensive network of field plots and global positioning system (GPS) collars deployed on cattle within four experimental pastures, each containing a mix of uncut forest, clear cut forest, partially harvested areas, and in-block haul roads, to examine habitat preferences during mid-summer grazing in 2008 and 2009. We also examined the effect of two cattle stocking rates the first year. Although cattle removed similar amounts of forage in all habitats, GPS data indicated cattle spent more time in uncut forests, and avoided clear cuts and in-block haul roads during both years, patterns that remained consistent under either livestock stocking rate tested. Observed patterns of habitat use were attributed to conservative cattle stocking rates consistent with or greater than those allocated on publicly grazed forest land in Alberta, combined with specific habitat attributes. Preferred use of uncut forest was attributed in part to favorable forage quality, which was positively associated with cattle utilization (standardized β=+0.13) among plots. Although forage use by cattle of plots also increased with forage biomass (β=+0.33), sharp increases in biomass following clear cut logging appeared to be offset by reductions in forage use associated with increased slash cover (β=−0.12) and sapling density (β=−0.11), both of which may have impeded cattle access. As a result, forage removal remained similar among habitats. Finally, cattle use of forage decreased with increasing distance from water (β=−0.22), highlighting the importance of ensuring reliable access to water across forested pastures to prevent localized overuse. Overall, the reduced time cattle spent in clear cut habitats coupled with similar forage removal suggests that under low cattle stocking rates, grazing can be compatible with deciduous forest management in the region.

Effectiveness of cattle operated bump gates and exclusion fences in preventing ungulate multi-host sanitary interaction

Tuberculosis (TB) is endemic in Eurasian wild boar (Sus scrofa) and red deer (Cervus elaphus) in south central Spain, where evidence suggests transmission to domestic cattle. Known risk factors for TB at the interface between livestock and wild ungulate species include density and spatial overlap, particularly around waterholes during summer. We evaluated the effectiveness of selective exclusion measures for reducing direct and indirect interaction between extensive beef cattle and wild ungulates at waterholes as an alternative for the integrated control of TB. We first monitored 6 water points (WP) with infrared-triggered cameras at a TB positive cattle farm to quantify interactions. We then assigned 3 WP to be “cattle-only” and 3 to be “wildlife-only”. Cattle-only WP were surrounded with a wildlife-proof fence (2.5m high) and an original design of cattle-specific gate. Wildlife-only WP were surrounded by a fence that wild ungulates could breach but cattle could not (1.2m high). Red deer, roe deer (Capreolus capreolus) and wild boar easily jumped or undercrossed this fence. Wildlife-only fences were 100% effective in preventing cattle access to WP and did not impede wildlife use. Many cows learned to operate the cattle-specific gate quickly and others followed and learned from them. Within 2 weeks, around 70% of cows actively entered and exited through the cattle-specific gate. We demonstrate how simple, low-cost fencing strategies can serve as biosecurity measures to substantially reduce direct and indirect contact between cattle and wild ungulates, serving to reduce the potential for TB transmission. Our designs can be used in the context of integral plans to mitigate disease transmission between cattle and wildlife, and have potential for protecting or segregating the use of a variety of resources in different contexts.

A Comparison of the Abortifacient Risk of Western Juniper Trees in Oregon

• The bark, leaves, and berries of western juniper trees in Oregon can cause abortions in late-term pregnant cattle. • The percentage of the abortion-causing compounds varied from tree to tree in a location, as well as between locations across Oregon, but did not appear to vary across time. • Cattle producers who winter cattle in pastures with western juniper trees should take cautions such as denying late-term pregnant cattle access to these pastures, providing adequate feed and shelter, maintaining pregnant cattle in good body condition, changing calving schedules to late spring or early fall, and, if abortions do occur, seeking veterinary care for any postpartum complications.

Impact of Riparian Zone Protection from Cattle on Nutrient, Bacteria, F-coliphage,Cryptosporidium, andGiardiaLoading of an Intermittent Stream

This 5-yr study compared, via an upstream-downstream experimental design, nutrient and microbial water quality of an intermittent stream running through a small pasture (∼2.5 animals ha) where cattle are restricted from the riparian zone (restricted cattle access [RCA]) and where cattle have unrestricted access to the stream (unrestricted cattle access [URCA]). Fencing in the RCA excluded pasturing cattle to within ∼3 to 5 m of the stream. Approximately 88% (26/32) of all comparisons of mean contaminant load reduction for lower, higher, and all stream flow conditions during the 5-yr study indicated net contaminant load reductions in the RCA; for the URCA, this percentage was 38% (12/32). For all flow conditions, mean percent load reductions in the RCA for nutrients and bacteria plus F-coliphage were 24 and 23%, respectively. These respective percentages for the URCA were -9 and -57% (positive values are reductions; negative values are increases). However, potentially as a result of protected wildlife habitat in the RCA, the mean percent load reduction for for "all flow" was -321% for the RCA and 60% for the URCA; for , these respective percentages were -209% (RCA) and 73% (URCA). For "all flow" situations, mean load reductions for the RCA were significantly greater ( < 0.1) than those from the URCA for NH-N, dissolved reactive phosphorus (DRP), total coliform, , and . For "high flow" situations, mean load reductions were significantly greater for the RCA for DRP, total coliform, and . For "low flow" conditions, significantly greater mean load reductions were in favor of the RCA for DRP, total P, total coliforms, fecal coliforms, , and . In no case were mean pollutant loads in the URCA significantly higher than RCA pollutant loads. Restricting pasturing livestock to within 3 to 5 m of intermittent streams can improve water quality; however, water quality impairment can occur if livestock have unrestricted access to a stream.

Source strengths, transport pathways and delivery mechanisms of nutrients, suspended solids and coliforms within a small agricultural headwater catchment

Analysis of water samples and accompanying flow data collected (on ~100 occasions) from well defined land drain outlets located in a small catchment in NE Scotland were made over a five year period. The complex relationship between individual sources that can exist even within a small (200ha) agriculturally managed headwater catchment was clearly evident. On average ~60% of the measured flow from the catchment outlet was accounted for, with ~50% originating from field drains and 10% from the farmyard. Certain field drains stopped flowing during the summer. Flow from the farmyard was continuous, and because livestock were present all year round also represented a renewable source of potential contaminants. The majority of nitrate and suspended sediment originated directly from field drainage. The variability in nitrate concentration between individual field drains was large and probably reflected differences in soil drainage properties. Farmyard drainage contributed a large proportion of the ammonium, phosphate and Faecal Indicator Organisms (FIO) measured as a flux from the catchment. On numerous sampling occasions the combined flux from individual sources was greater than the corresponding loss measured at the catchment outlet. This was attributed to result from the temporary storage/retention mechanisms (sedimentation, transformation or biological uptake/exchange) that can operate within the stream channel. Despite many fields being grazed and/or receiving regular applications of slurry/manure, the majority ~60% of the total flux of FIO still originated from the ‘farmyard’, with significant contributions from the field drains only occurring during the autumn. The presence of field drinkers and secure well maintained fencing denying cattle access to the open drainage channel (often a recommended best management practice) may well have contributed to this observation. Benefits to water quality that might arise from riparian management, such as buffer strips in this particular situation may be limited due to the dominant contribution originating from land drains and farmyard.

Assessing Riparian Conservation Land Management Practice Impacts on Gully Erosion in Iowa

Well-established perennial vegetation in riparian areas of agricultural lands can stabilize the end points of gullies and reduce their overall erosion. The objective of this study was to investigate the impacts of riparian land management on gully erosion. A field survey documented the number of gullies and cattle access points in riparian forest buffers, grass filters, annual row-cropped fields, pastures in which the cattle were fenced out of the stream, and continuously, rotationally and intensive rotationally grazed pastures in three regions of Iowa. Gully lengths, depths and severely eroding bank areas were measured. Gullies exhibited few significant differences among riparian management practices. The most significant differences were exhibited between conservation and agricultural management practices, an indication that conservation practices could reduce gully erosion. Changes in pasture management from continuous to rotational or intensive rotational grazing showed no reductions in gully erosion. It is important to recognize that more significant differences among riparian management practices were not exhibited because the conservation and alternative grazing practices had recently been established. As gully formation is more impacted by upland than riparian management, gully stabilization might require additional upland conservation practices. The existence of numerous cattle access points in pastures where cattle have full access to the stream also indicates that these could be substantial sources of sediment for streams. Finally, the gully banks were less important sediment contributors to streams than the streambanks. The severely eroding bank areas in streams were six times greater than those in the gullies in the monitored reaches.

Widespread Occurrence of Ranavirus in Pond-Breeding Amphibian Populations

Ranaviruses are an emerging threat for many amphibian populations, yet their distribution in amphibian communities and the association of infection with possible stressors and species is not fully understood due to historically sparse surveillance. Agricultural practices that reduce the water quality of amphibian breeding habitats (e.g., cattle access to wetlands) and environmental stressors (e.g., lower temperatures) may contribute to ranavirus emergence. We tested larval amphibians for ranavirus infection across four seasons in farm ponds (n=40) located in Tennessee, USA. Cattle at various densities were allowed access to half of the sampled ponds. Ranavirus infections were detected in nine species and in 33 of the sampled ponds (83%), illustrating widespread occurrence of the pathogen. Species within the family Ranidae were the most frequently infected. In 13 of the ponds containing infected individuals, prevalence exceeded 40% during at least one season. Infections were detected in multiple seasons in 20 of the sampled ponds containing infections, suggesting that ranaviruses are relatively persistent in these systems. Cattle had negative effects on water quality (turbidity and ammonia) and there was a positive association between cattle abundance and ranavirus prevalence in the summer. Counter to previous field studies in North America, we found a significant positive association between water temperature and ranavirus prevalence in the fall sampling events. Despite these findings, the influences of cattle and temperature on ranavirus prevalence were not consistent across seasons. As such, the mechanisms driving high ranavirus prevalence across the landscape and over time remain unclear. Given the widespread occurrence of ranaviruses in wild amphibians, we encourage the implementation of surveillance programs to help identify potential drivers of emergence. Sites with high ranavirus prevalence should be monitored annually for outbreaks, and the long-term effects on population size determined.

Bovine cysticercosis in Ethiopia: A review

Bovine cysticercosis is an infection of cattle caused by Cysticercus bovis, the larval stage of Taenia saginata. It is an infection of public health significance as eating of raw or undercooked beef results taeniasis in human population and an important cause of economic loss mainly due to condemnation, refrigeration and downgrading of infected carcasses. Bovine cysticercosis is prevalent in cattle population of various regions of Ethiopia in a range of 2.2% to 26.25%. The reported rates of prevalence may be an underestimate because employment of the latest diagnostic methods is uncommon and the routine meat inspection is the only method in use. Habit of eating raw beef dishes, low level of toilet use by human population, backyard slaughter, low availability of taenicides, free access of cattle to surface water, and proximity of wastewater are important causes for transmission of bovine cysticercosis to a herd of cattle and taeniasis in human population and such practices are not uncommon in Ethiopia. Competent meat inspection procedure supported by immunodiagnostics, chemotherapy and vaccination are the recommended approaches to prevent bovine cysticercosis and therefore such approaches along with the current status of bovine cysticercosis in Ethiopia are highlighted in the present review.

Environmental quality of Lower Little Bow River and riparian zone along an unfenced reach with off-stream watering

► We evaluated off-stream watering on riparian zone and river. ► Off-stream watering reduced cattle on the river bank and in river. ► The BMP improved riparian health and prevented river pollution by cattle. ► Certain vegetative properties were improved at the cattle access site. ► Rainfall simulation quality at cattle access site was not affected. The goal of beneficial management practices (BMPs) such as off-stream watering without fencing is to direct cattle away from rivers, improve the environmental quality of the riparian zone, and prevent or reduce river pollution. We conducted a four year (2005–2008) study on an unfenced 1.3 km reach of the Lower Little Bow (LLB) River in southern Alberta, Canada where three off-stream watering systems were installed 290 to ≥730 m from the river in August, 2005. Our hypothesis was that off-stream watering would reduce cattle activity at the river, improve riparian health, prevent river pollution by cattle, and improve the soil, vegetative, and rainfall simulation runoff variables at a cattle access site near the river. Off-stream watering did not significantly ( p > 0.10) reduce the median number of cattle on the river bank, in the river, or drinking from the river one year later. However, there was a reduction of 20% ( p = 0.15) for median number of cattle on the river bank and a 72% reduction ( p = 0.20) for cattle in the river. The BMP moderately improved the riparian health score from 60% (2005) to 65% (2007). Our spatial analysis (upstream–downstream) of base-flow during the post-BMP period (2006–2008) suggested that off-stream watering prevented river pollution by cattle for the majority of water quality variables measured. Canopy cover at the cattle access site near the river was significantly ( p ≤ 0.10) increased by 26–53% one and two years after the BMP. Two years after the BMP was implemented, total basal area, biomass, and mulch were significantly increased by 37–106%, while bare soil and NO 3 -N in surface soil were decreased by 38–89%, respectively. In contrast, other vegetative and soil properties were not significantly improved. Concentrations of the majority of N and P fractions in rainfall simulation runoff were not significantly reduced, and may be related to the high precipitation in the pre-BMP year of 2005. We accept the hypothesis that off-stream watering improved riparian health, prevented river pollution by cattle, and improved certain vegetative (canopy cover, total basal area, mulch, bare soil) and soil properties (soil NO 3 -N) near the river. However, we reject the hypothesis that off-stream watering improved other vegetation (live basal area) and soil properties (bulk density, NH 4 -N, total N and C), or improved rainfall simulation runoff quality near the river. Although we cannot statistically prove that the positive benefits of off-stream watering on certain environmental variables was due to reduced cattle activity, the non-significant reductions in cattle activity suggested this may be a possibility.

Effects of Livestock Grazing on Grasshopper Abundance on a Native Rangeland in Montana

Livestock grazing can affect habitat quality for grasshoppers through effects on food and oviposition site availability, microclimate, and other factors. Because of this, some authors have suggested that grazing programs can be used to help manage pest grasshopper populations. In a 6-yr study, we controlled access of cattle to replicated experimental plots on an Agropyron spicatum/Poa sandbergii pasture to create consistent year-to-year differences in postgrazing plant cover, with resultant affects on microclimate. After sampling grasshoppers multiple times after grazing treatments each summer, we found evidence of between-treatment differences in grasshopper abundance for the entire assemblage during 4 of the 6 yr. Some species, including Melanoplus sanguinipes (perhaps the worse rangeland grasshopper pest in the western United States), tended to be more abundant on ungrazed plots, whereas Melanoplus gladstoni often had greater densities on heavily-grazed plots. The effect of grazing on grasshopper densities in this study was lower in magnitude and less consistent among years than in a study we conducted simultaneously at a nearby site where the vegetation was dominated by the exotic species crested wheatgrass (Agropyron cristatum). Our results generally support proposals that grazing could be used to reduce pest grasshopper densities, although the effectiveness of a particular grazing scheme may vary among sites, years, and grasshopper and vegetation assemblages.

Soil test phosphorus and nitrate adjacent to artificial and natural cattle watering sites in southern Alberta

Off-stream watering troughs may reduce surface water pollution by keeping nutrients away from natural water bodies, but may increase nutrient contaminant of groundwater. The objective of this study was to determine to what extent off-stream watering troughs active for 2 to 7 yr caused enrichment and leaching of soil test P (STP) and KCl-extractable NO3-N. The study was conducted in the Lower Little Bow (LLB) River watershed of southern Alberta, Canada. Soil samples were obtained at three recently installed off-stream watering troughs, four active cattle watering sites adjacent to the LLB River, and at two sites along a fenced reach of the river with no cattle access. At each location, samples were obtained along four 100-m transects. Surface (0-5 cm) soil immediately adjacent to the LLB River was not enriched in STP or NO3-N, which was attributed to flushing of nutrients during periods of high flow. Surface soil at distances ≤ 5 m from the three water troughs was approximately three times higher in STP than surface soil obtained at distances ≥10 m and was seven times higher in NO3-N. Subsurface soil layers adjacent (3 m distance) to the three water troughs were not enriched in STP compared with background levels (100 m distance). The subsurface soil adjacent (3 m) to the longest active watering trough was enriched in NO3-N to the 60 cm depth compared with background levels (100 m). Greater nutrient enrichment at the off-stream watering troughs than at the cattle watering sites adjacent to the river suggested that this beneficial management practice (BMP) was effective in shifting nutrient distribution away from the river. Key words: Pasture, nutrient leaching, nitrate, best management practices

Physicochemical characteristics of Lake IRAD, an artificial lake in Wakwa region, Cameroon

AbstractWakwa is a region in north Cameroon characterized by intensive cattle production. This study evaluated the physicochemical characteristics of the waters in Lake IRAD, located near Wakwa, which is the main water source for cattle grazing in this area. Water samples were collected at four sampling sites during the rainy and dry seasons (April, July, October and February). The chemical composition of the water samples was analysed for various constituents, including nitrate (NO3–), chloride (Cl−), phosphate (PO43−), bicarbonate (HCO3−), calcium (Ca), magnesium (Mg), manganese (Mn), aluminium (Al), zinc (Zn), copper (Cu), iron (Fe), nickel (Ni), cadmium (Cd), ammonia–nitrogen (NH4–N) and organic matter (OM). The mineral composition varied significantly (P &lt; 0.05) with the sampling period. High concentrations of zinc (0.96 mg L−1) and dissolved iron (1.23 mg L−l) were observed during the dry season. Total iron (3.25 mg L−1), OM (15.4 mg of O2 L−1), nitrate (28.82 mg L−1) and NH4–N (1.05 mg L−1) concentrations were highest during the rainy season. The iron, OM and NH4–N concentrations were higher than the USEPA‐recommended values (0.2 mg L−1, 4 mg of O2 L−1 and 0.5 mg L−1, respectively). The phosphate, copper, nickel and cadmium concentrations, considered as the polluting substances, were present in negligible concentrations, being below the detection limits of the analytical techniques used to measure them. The high iron, OM and nitrogen concentrations were attributed to water‐leached soil run‐off, as well as the activity of animals in the lake. Sampling sites 1 and 2, which were used mostly by cattle, were observed to have the highest concentrations of NH4–N, compared with sites 3 and S (exit point). It will be necessary to delimit cattle access points to the lake to reduce this type of contamination of drinking water.

Cost‐effective alternatives for mitigating Cryptosporidium risk in drinking water and enhancing ecosystem services

Under the multibarrier paradigm, water quality management barriers that mitigate risk to consumers are required at multiple points from the catchment to the tap. We present a cost‐effectiveness analysis of 13 catchment‐ and treatment‐based management alternatives for mitigating Cryptosporidium risk in the Myponga water supply catchment, South Australia. A broad range of costs and benefits are identified and valued, including setup, operation and maintenance, and opportunity costs, and benefits for ecosystem services including water quality, biodiversity, carbon sequestration, and farm production services. The results suggest that the cost‐effectiveness of investment in water quality management can be substantially enhanced by considering the costs of management and the benefits for ecosystem services, in addition to Cryptosporidium removal effectiveness. Cost‐effectiveness of investment in management alternatives is dependent upon the desired level of Cryptosporidium removal effectiveness by both the catchment and treatment barriers. The combination of a spatially targeted 25% restriction in water course access of nondairy cattle and treatment by enhanced coagulation provides the most (net) cost‐effective Cryptosporidium risk mitigation strategy. This combination may achieve 0.614 log removal at a net cost of A$0.7 million and (net) cost‐effectiveness of A$1.14 million per log removal. Additional risk mitigation can be achieved through the addition of ultraviolet irradiation treatment, higher levels of water course access restriction for cattle, and the adoption of dung beetles in the catchment. Economic valuation of a range of costs and benefits of management priorities can support cost‐effective water quality management investment decisions and inform elements of policy design such as cost‐sharing arrangements and spatial targeting.

Differential Responses of Postmetamorphic Amphibians to Cattle Grazing in Wetlands

ABSTRACT Global amphibian declines have been linked to various anthropogenic land uses. Recent studies have documented negative impacts of cropland agriculture and deforestation on amphibians; however, few have examined potential impacts of cattle grazing in wetlands on resident amphibians. Therefore, we measured differences in number of captures and body size of postmetamorphic amphibians, egg mass abundance, and shoreline vegetation structure and composition between 4 wetlands with direct cattle access and 4 wetlands from which cattle were excluded on the Cumberland Plateau in Tennessee, USA. We captured amphibians at wetlands from March to August 2005 and 2006 using pitfall traps. Number of green frog (Rana clamitans) metamorphs captured at nonaccess wetlands was 2.5 times and 9.8 times greater than at wetlands with cattle access in 2005 and 2006, respectively. However, number of American toads (Bufo americanus) captured was 68 times and 76 times greater at cattle‐access wetlands in 2005 and 2006, respectively. In general, metamorph body size was negatively correlated with species‐specific capture rate. We detected no differences in egg mass abundance between cattle land‐use types. Height, percent horizontal cover, and percent vertical cover of shoreline vegetation were 74%,25%, and 84% greater, respectively, in nonaccess wetlands in 2005; vegetation trends were similar in 2006. Our results suggest that cattle impact amphibian populations but effects vary by species. Differences in postmetamorphic capture rate may be related to less emergent vegetation at cattle‐access wetlands. Although body size differed between land uses for metamorphs, these trends probably were short‐lived, because we did not detect differences in juvenile and adult body size between land uses for most species. Based on our findings, we suggest that fencing cattle from wetlands may be a prudent conservation strategy for some amphibian species (e.g., ranids), whereas other species (e.g., bufonids) may benefit from controlled grazing.

Short-Term Effect of Cattle Exclosures on Columbia Spotted Frog (Rana luteiventris) Populations and Habitat in Northeastern Oregon

Livestock grazing is a common land use across the western United States, but concerns have been raised regarding its potential to affect amphibian populations. We studied the short-term effects of full and partial livestock grazing exclosures on Rana luteiventris (Columbia Spotted Frog) populations using a controlled manipulative field experiment with pre- and posttreatment data (2002-2006). Despite a significant increase in vegetation height within grazing exclosures, we did not find treatment effects for egg mass counts, larval survival, or size at metamorphosis 1-2 years following grazing exclosure installation. Water samples taken in late summer showed concentrations of nitrite, nitrate, ammonia, and orthophosphate that were low or near detection limits across all ponds and years. The results of this experiment do not support a hypothesis that limiting cattle access to breeding ponds will help conserve R. luteiventris populations in our study area. Further research is needed to evaluate regional variation and long-term effects of grazing exclosures on R. luteiventris populations.

Livestock exclusion influences on riparian vegetation, channel morphology, and benthic macroinvertebrate assemblages

Measurements in paired stream reaches with and without livestock access in southwestern Virginia suggest that livestock exclusion practices installed on short, isolated stream reaches result in improved geomorphic and riparian vegetation conditions, but do not significantly improve benthic macroinvertebrate assemblages. Numerous state and federal programs encourage agricultural producers to protect environmentally sensitive lands (such as streams and wetlands) through the elimination of livestock access to these sensitive areas. In addition to achieving soil conservation goals, it is widely believed that livestock exclusion from streams will result in improvements in riparian vegetation, channel morphology, as well as instream habitat and aquatic insect assemblages. This research assessed the changes in channel morphology, riparian vegetation, and benthic macroinvertebrate assemblages as affected by livestock exclusion over time. Study sites consisted of paired, nearly contiguous stream reaches (five pairs), with and without active livestock access, across a range of time since livestock exclusion was implemented. Four of the livestock exclusion reaches ranged in time since best management practice implementation from 1 to 14 years, while one site consisted of a grazed reach paired with a reach that has been forested and without cattle access for at least 50 years. Livestock exclusion reaches were significantly deeper, had larger median riffle substrate, and scored higher on the Reach Condition Index (a qualitative geomorphic assessment methodology). The livestock exclusion reaches also had significantly higher riparian groundcover vegetation biomass; however, the benthic macroinvertebrate assemblages were not significantly different. The only parameter that showed correlation with time since livestock exclusion was the Reach Condition Index, which increased (indicating improved bank stability) with time since livestock exclusion. Our observations suggest that, while livestock exclusion from streams has positive impacts on streams, best management practice implementation along short stream stretches does not have the desired instream benefits. In particular, benthic macroinvertebrate response depends more on upstream watershed-scale conditions and impacts than localized, reach-scale livestock-access issues. Therefore, a more targeted approach addressing entire stream lengths and the associated watersheds may be required to restore the integrity of aquatic ecosystems.