Pasture Cover Research Articles

MEASUREMENT OF BIOLOGICAL DIVERSITY OF ARTHROPODS AND RESPIRATION IN SOILS MANAGED UNDER TIME-CONTROLLED AND SET-STOCKED GRAZING PRACTICES IN CENTRAL-WEST NEW SOUTH WALES, AUSTRALIA

In this study we compare the effects of two contrasting grazing regimes (time-controlled grazing (TCG) vs set-stocked grazing (SSG)) on selected parameters of soil biological health . The purpose of the study was to evaluate these soil parameters as potential indicators of soil health and thence sustainable soil management. Two parameters, viz., arthropod biological diversity and soil respiration were chosen as reliable indicators of soil health. Samples of pasture cover, arthropod populations, and soil from varied depths were obtained in spring (September-November 2010) and autumn (March-May 2011). Results from the autumn showed a strong effect of time-controlled grazing with increased arthropod abundance and enhanced soil biological respiration while in spring the differences were not significant. It was concluded that a change to short-duration rotational grazing can be beneficial to soil biological health in the longer term and that the measurement of arthropods present in the litter and topsoil can be a simple yet effective indicator of the impact of grazing regime on soil health.

β-diversity decline of aquatic insects at the microhabitat scale associated with agricultural land use

Several studies report the decline of β diversity caused by agricultural impacts in river ecosystems. However, the susceptible scale of β diversity to agricultural impacts and the indirect effects on β diversity within hierarchically nested ecosystems are unclear. We first tested the hypothesis that β diversity between microhabitats is significantly influenced by agricultural land use. We also examined the indirect effects of agricultural land use on α and β diversities at the microhabitat scale. Twelve microhabitat samples (25 cm2) were collected at 27 reaches within Kitamihorobetsu River, Japan. All reaches were classified into three agricultural intensities based on pasture area (low, middle, and high), and their hierarchical diversities (microhabitat, reach, and catchment) were calculated using additive partitioning. Indirect effects were demonstrated by structural equation modelling using indirect and direct environmental gradients. The α and β diversities at the microhabitat scale decreased significantly with agricultural intensity. Increasing pasture cover within catchments showed a negative correlation with habitat heterogeneity and water quality (habitat homogenization and water degradation) and a positive correlation with sand cover on streambeds (sedimentation of fine particles). The α diversity decreased with sedimentation of fine particles, and the β diversity decreased with habitat homogenization and water degradation. Our findings suggest that species diversity of aquatic insects at the microhabitat scale would be susceptible to agricultural land use. Furthermore, we emphasize that the diversity index used to evaluate restoration projects should be carefully selected because influential abiotic factors were different between α and β diversities.

Seed bank persistence and germination of chinee apple (Ziziphus mauritiana Lam.)

Chinee apple (Ziziphus mauritiana Lam.) is a thorny tree that is invading tropical woodlands of northern Australia. The present study reports three experiments related to the seed dynamics of chinee apple. Experiment 1 and 2 investigated persistence of seed lots under different soil types (clay and river loam), levels of pasture cover (present or absent) and burial depths (0, 2.5, 10 and 20 cm). Experiment 3 determined the germination response of chinee apple seeds to a range of alternating day/night temperatures (11/6°C up to 52/40°C). In the longevity experiments (Expts 1 and 2), burial depth, soil type and burial duration significantly affected viability. Burial depth had the greatest influence, with surface located seeds generally persisting for longer than those buried below ground. Even so, no viable seeds remained after 18 and 24 months in the first and second experiment, respectively. In Expt 3 seeds of chinee apple germinated under a wide range of alternating day/night temperatures ranging from 16/12°C to 47 /36°C. Optimal germination (77%) occurred at 33/27°C and no seeds germinated at either of the lowest (11/6°C) or highest (52/40°C) temperature regimes tested. These findings indicated that chinee apple has the potential to expand its current distribution to cooler areas of Australia. Control practices need to be undertaken for at least two years to exhaust the seed bank.

PM 9/20 (1) Parthenium hysterophorus

PM 9/20 (1) <i>Parthenium hysterophorus</i>

Redundância entre métricas da qualidade ambiental de riachos em paisagem agrícola

Biological indicators are widely used for the evaluation of the environmental quality of waterbodies. Since monitoring involves high sampling costs, and the creation of multimetric indices assumes uncorrelated metrics, this study evaluated whether there was correlation among metrics that characterize land use and cover, riparian zone composition and forest structure, as well as correlations among indicators of macroinvertebrate and fish communities. The study was conducted on 12 low-order tributaries of the Jacare-Pepira and Jacare-Guacu Rivers, forming a gradient of environmental stress in the central region of Sao Paulo State. There were no correlations among land use metrics, and only pasture cover was correlated with some metrics of riparian forest structure. Therefore, both information on land use and riparian composition and forest structure can be important in the environmental assessment of streams. All metrics related to macroinvertebrate communities were correlated to each other, as well as most metrics related to fish communities, although most studies proposing multimetric indices have not found correlation among these metrics. Those studies evaluated streams in extreme situations (preserved vs. impacted), and impacted streams were influenced by different degradation drivers, which may result in distinct responses by the biological communities. The results of the present study suggest that the development of indices must be specific to the studied region, and that frequently the evaluations are carried out in relation to specific drivers of impact, which may vary for different systems.

Patterns and predictors of β-diversity in the fragmented Brazilian Atlantic forest: a multiscale analysis of forest specialist and generalist birds.

Biodiversity maintenance in human-altered landscapes (HALs) depends on the species turnover among localities, but the patterns and determinants of β-diversity in HALs are poorly known. In fact, declines, increases and neutral shifts in β-diversity have all been documented, depending on the landscape, ecological group and spatial scale of analysis. We shed some light on this controversy by assessing the patterns and predictors of bird β-diversity across multiple spatial scales considering forest specialist and habitat generalist bird assemblages. We surveyed birds from 144 point counts in 36 different forest sites across two landscapes with different amount of forest cover in the Brazilian Atlantic forest. We analysed β-diversity among points, among sites and between landscapes with multiplicative diversity partitioning of Hill numbers. We tested whether β-diversity among points was related to within-site variations in vegetation structure, and whether β-diversity among sites was related to site location and/or to differences among sites in vegetation structure and landscape composition (i.e. per cent forest and pasture cover surrounding each site). β-diversity between landscapes was lower than among sites and among points in both bird assemblages. In forest specialist birds, the landscape with less forest cover showed the highest β-diversity among sites (bird differentiation among sites), but generalist birds showed the opposite pattern. At the local scale, however, the less forested landscape showed the lowest β-diversity among points (bird homogenization within sites), independently of the bird assemblage. β-diversity among points was weakly related to vegetation structure, but higher β-diversity values were recorded among sites that were more isolated from each other, and among sites with higher differences in landscape composition, particularly in the less forested landscape. Our findings indicate that patterns of bird β-diversity vary across scales and are strongly related to landscape composition. Bird assemblages are shaped by both environmental filtering and dispersal limitation, particularly in less forested landscapes. Conservation and management strategies should therefore prevent deforestation in this biodiversity hotspot.

Parâmetros Indicativos para Qualidade da Água em Nascentes com Diferentes Coberturas de Terra e Conservação da Vegetação Ciliar

O objetivo desta pesquisa foi avaliar e comparar a qualidade da água de quatro nascentes em diferentes coberturas de terra e conservação da vegetação no Córrego Pimenta. As coletas de água foram realizadas mensalmente durante um ano, avaliando dez parâmetros físico-químicos, sendo que os dados foram submetidos ao Teste de Tukey. A nascente um (N1) possui mata ciliar preservada; a nascente dois (N2) possui mata ciliar perturbada; a nascente três (N3) possui bambuzal e mata ciliar, e está degradada; a nascente quatro (N4) tem cobertura de pastagem e se encontra em degradação. As nascentes N1 e N2 tiveram os valores inferiores em temperatura, turbidez, cor, nitrato, nitrito e ferro, e valores próximos à neutralidade em pH. A N3 mostrou os valores inferiores para condutividade elétrica, TDS, salinidade e pH. As nascentes N1 e N2 indicaram que sete parâmetros foram melhores na qualidade da água, demonstrando que a mata ciliar auxilia em sua proteção qualitativa da água.

Water and sediment loss through runoff in areas of forest and pasture cover in southwestern Amazonia – Acre – Brazil

Water and sediment loss through runoff in areas of forest and pasture cover in southwestern Amazonia – Acre – Brazil

Avaliação qualitativa de nascentes com diferentes coberturas do solo e conservação da vegetação em seu entorno no córrego Pimenta

The sources lose their qualitative and quantitative capacity of water, when it is changed by human actions. The objective of this research was to qualitative evaluation of four sources, to evaluate the positive and negative impacts on their surroundings in creek Pepper as well as the framing of each source in CONAMA Resolution 357/05. For the physical characterization of the sources and their surroundings were classified as preserved, disturbed or degraded, beyond the positive and negative environmental impacts. Sampling of surface water were made ​​in the period of one year , with ten physicochemical parameters monitored. The first source (N1) it is preserved and presents coverage of riparian forest. The source two (N2) has coverage of riparian forest and is in a state of disturbance. The source three (N3) has coverage of bamboo forest and natural forest and it is degraded. The source four (N4) has pasture cover and is in degradation. The adjust of physico-chemical parameters had the N1 within the standards for Class II, the N2 is adjusting for Class III , N3 and N4 did not show the values allowed in class II and III. The sources preserved and disturbed with riparian vegetation had all positive impacts, while degraded sources have the most negative impacts. The presence of riparian vegetation in disturbed and preserved sources auxiliary in qualitative protection of water resources compared the degraded sources.

Potential impacts of different spring grazing strategies on lamb finishing in hill country

How does the pasture cover at the beginning of lambing and the grazing strategy used in early spring influence the ability of a hill country sheep and beef farm to finish lambs? The results from an intensive pasture-mowing trial investigating three defoliation intensities (Lax, Moderate and Intense) starting from two herbage masses (1200 or 1500 kg DM/ha) during early spring were used to provide data on potential pasture consumption and feed quality from lambing to weaning for a breeding ewe flock. Using simulation modelling, this pasture data was used to estimate the potential lamb and ewe liveweight changes from birth to weaning at each of three different stocking rates (4.5, 8 and 10.5 twin-bearing ewes/ha) that closely represented the three defoliation intensities originally studied in a mowing trial. The impacts of these early-spring herbage masses and grazing intensities/ stocking rates on subsequent feed requirements and potential lamb finishing during the later summer and autumn period in four contrasting geo-climatic regions of New Zealand were then further investigated using simulation modelling. Variations in ewe and lamb weaning weights were evident and reflected the amount of pasture available through the different grazing management approaches. For all four geoclimatic regions studied, the Intense grazing, high stocking rate strategy generally produced the greatest gross revenue per ha from lamb sales out of the three grazing strategies investigated, though not significantly greater than the moderate stocking rate in summer dry environments. However, under Intense grazing, a high pasture cover (1500 kg DM/ha), in comparison to a low pasture cover (1200 kg DM/ha) at the start of ewe lactation further improved the gross revenue received from lamb sales, especially in the Canterbury and Waikato environments but less so in the Hawke's Bay and Southland environments. These variations demonstrate how iterations based on the same starting properties impact on weaning weight of lambs and post-weaning pasture growth and/or feed quality. Keywords: emergence, feed supply, geo-climatic regions, iteration, lactation, lamb weaning weight, pasture quality.

Regular estimates of paddock pasture mass can improve profitability on New Zealand dairy farms

Paddock selection is an important component of grazing management and is based on either some estimate of pasture mass (cover) or the interval since last grazing for each paddock. Obtaining estimates of cover to guide grazing management can be a time consuming task. A value proposition could assist farmers in deciding whether to invest resources in obtaining such information. A farm-scale simulation exercise was designed to estimate the effect of three levels of knowledge of individual paddock cover on profitability: 1) "perfect knowledge", where cover per paddock is known with perfect accuracy, 2) "imperfect knowledge", where cover per paddock is estimated with an average error of 15%, 3) "low knowledge", where cover is not known, and paddocks are selected based on longest time since last grazing. Grazing management based on imperfect knowledge increased farm operating profit by approximately $385/ha compared with low knowledge, while perfect knowledge added a further $140/ha. The main driver of these results is the level of accuracy in daily feed allocation, which increases with improving knowledge of pasture availability. This allows feed supply and demand to be better matched, resulting in less incidence of under- and over-feeding, higher milk production, and more optimal post-grazing residuals to maximise pasture regrowth. Keywords: modelling, paddock selection, pasture cover

Seed bank longevity and age to reproductive maturity of Calotropis procera (Aiton) W.T. Aiton in the dry tropics of northern Queensland

Understanding the reproductive biology of Calotropis procera (Aiton) W.T. Aiton, an invasive weed of northern Australia, is critical for development of effective management strategies. Two experiments are reported on. In Experiment 1 seed longevity of C. procera seeds, exposed to different soil type (clay and river loam), pasture cover (present and absent) and burial depth (0, 2.5, 10 and 20 cm) treatments were examined. In Experiment 2 time to reach reproductive maturity was studied. The latter experiment included its sister species, C. gigantea (L.) W.T. Aiton, for comparison and two separate seed lots were tested in 2009 and 2012 to determine if exposure to different environmental conditions would influence persistence. Both seed lots demonstrated a rapid decline in viability over the first 3 months and declined to zero between 15 and 24 months after burial. In Experiment 1, longevity appeared to be most influenced by rainfall patterns and associated soil moisture, burial depth and soil type, but not the level of pasture cover. Experiment 2 showed that both C. procera and C. gigantea plants could flower once they had reached an average height of 85 cm. However, they differed significantly in terms of basal diameter at first flowering with C. gigantea significantly smaller (31 mm) than C. procera (45 mm). On average, C. gigantea flowered earlier (125 days vs 190 days) and set seed earlier (359 days vs 412 days) than C. procera. These results suggest that, under similar conditions to those that prevailed in the present studies, land managers could potentially achieve effective control of patches of C. procera in 2 years if they are able to kill all original plants and treat seedling regrowth frequently enough to prevent it reaching reproductive maturity. This suggested control strategy is based on the proviso that replenishment of the seed bank is not occurring from external sources (e.g. wind and water dispersal).

Floristic composition and pasture condition of Aristida/Bothriochloa pastures in central Queensland. II. Soil and pasture condition interactions

Sustainable management of native pastures requires an understanding of what the bounds of pasture composition, cover and soil surface condition are for healthy pastoral landscapes to persist. A survey of 107 Aristida/Bothriochloa pasture sites in inland central Queensland was conducted. The sites were chosen for their current diversity of tree cover, apparent pasture condition and soil type to assist in setting more objective bounds on condition ‘states’ in such pastures. Assessors’ estimates of pasture condition were strongly correlated with herbage mass (r = 0.57) and projected ground cover (r = 0. 58), and moderately correlated with pasture crown cover (r = 0.35) and tree basal area (r = 0.32). Pasture condition was not correlated with pasture plant density or the frequency of simple guilds of pasture species. The soil type of Aristida/Bothriochloa pasture communities was generally hard-setting, low in cryptogam cover but moderately covered with litter and projected ground cover (30–50%). There was no correlation between projected ground cover of pasture and estimated ground-level cover of plant crowns. Tree basal area was correlated with broad categories of soil type, probably because greater tree clearing has occurred on the more fertile, heavy-textured clay soils. Of the main perennial grasses, some showed strong soil preferences, for example Tripogon loliiformis for hard-setting soils and Dichanthium sericeum for clays. Common species, such as Chrysopogon fallax and Heteropogon contortus, had no strong soil preference. Wiregrasses (Aristida spp.) tended to be uncommon at both ends of the estimated pasture condition scale whereas H. contortus was far more common in pastures in good condition. Sedges (Cyperaceae) were common on all soil types and for all pasture condition ratings. Plants identified as increaser species were Tragus australianus, daisies (Asteraceae) and potentially toxic herbaceous legumes such as Indigofera spp. and Crotalaria spp. Pasture condition could not be reliably predicted based on the abundance of a single species or taxon but there may be scope for using integrated data for four to five ecologically contrasting plants such as Themeda triandra with daisies, T. loliiformis and flannel weeds (Malvaceae).

A more quantitative approach to pasture renewal

On New Zealand dairy farms the level of pasture renewal has been estimated at 6% and 8%, with one analysis suggesting greater levels would benefit the economy. There is little research on how farmers set a renewal level, but we suggest five main drivers: crop requirement, historical, an event response, development and cost/benefit driven. This paper presents a case study using a cost/benefit approach to pasture renewal for Willsden dairy farm in Canterbury, which has renewed 28% and 38% of the property in the last 2 seasons. On this farm spray-drilling Italian ryegrass has shown an estimated 1.7 t DM/ha/year extra yield in the season of sowing, with a net value of $1090/ha, suggesting a payback period of around 5 months and a 198% return within the season of sowing. This case study shows there is a significant opportunity for dairy farmers to profit from better use of weekly pasture cover information to plan pasture renewal, to better assess the success of any renewal, and for pasture management software developers to provide automated analysis options to support a cost/benefit pasture renewal strategy. Keywords: pasture renewal, spray-drill, spraycultivate, perennial ryegrass, Italian ryegrass

Factors influencing natural regeneration of totara (Podocarpus totara D.Don) on grazed hill country grassland in Northland, New Zealand

There is increasing interest in establishing indigenous forests on marginal pastoral hill country in New Zealand to improve soil conservation, water quality and indigenous biodiversity. Large-scale reforestation using native seedlings is extremely costly. However, given suitable seed sources, it is possible to encourage natural regeneration of grassland into native plants. A grazed, sloping pasture site in Northland where totara (Podocarpus totara D.Don) regeneration had been allowed to develop over a 10-year period was assessed using a grid of 2-metre diameter plots. Counts of regenerating woody species and cover of herbaceous species were obtained in each plot. Plots were classified on the basis of herbaceous species cover using the TWINSPAN classification procedure. Regression analyses were used to identify site factors and characteristics of the herbaceous vegetation associated with totara regeneration. More than 7,000 stems ha−1 of woody species, mostly totara and gorse (Ulex europaeus L.), had accumulated over the 10-year period despite the presence of cattle grazing. Regeneration of totara was associated with steeper slopes and sites with the greatest diversity of herbaceous species but with lower overall levels of herbaceous cover. The regeneration pattern of the other main woody species was similar although gorse colonised a wider range of sites. Regeneration of woody species was absent on flatter sites, which were dominated by a few high-fertility tolerant herbaceous species and had high levels of herbaceous cover. This study has shown that regeneration of totara on a pastoral hill-country site was most prevalent on steeper slopes of lower fertility with typically sparse vegetation cover comprising low fertility tolerant herbaceous species. Conversely, totara regeneration was absent on flatter areas of higher fertility. It seems likely that grazing assists totara regeneration by keeping pasture cover short, thus increasing light levels near ground level for newly germinated seedlings. The propensity for totara to regenerate on pastoral hill country in the presence of grazing and where there is a nearby seed source could provide a practical option for re-establishing indigenous woody vegetation on erosion-prone marginal land.

Can Organic Amendments Be Useful in Transforming a Mediterranean Shrubland into a Dehesa?

AbstractTransforming a shrubland into a dehesa system may be useful for recovering certain productive and regulatory functions of ecosystems such as grazing potential, soil erosion control, and also for reducing the risk of wildfire. However, the productivity of the herbaceous cover and tree development in the transformed system may be limited by soil fertility, especially after wildfire events. Previous studies have shown that adequate doses of sewage sludge may improve soil fertility and facilitate plant recovery, but few studies have focused on plant biodiversity assessment. Here, we compare the effects of sewage sludge that has undergone different post‐treatments (dewatering, composting, or thermal drying) as a soil amendment used to transform a fire‐affected shrubland into a dehesa, on tree growth and pasture composition (vegetation cover, species richness, and diversity). In the short term, sewage sludge causes changes in both pasture cover and tree growth. Although no major differences in vegetation species richness and composition have been detected, fertilization using sewage sludge was shown to modify the functional diversity of the vegetation community. Rapid replacement of shrubs by herbaceous cover and ruderal plants (e.g. Bromus hordeaceus and Leontodon taraxacoides) and of the three grass species sown (Festuca arundinacea, Lolium perenne, and Dactylis glomerata) was observed, whereas N‐fixing species (leguminous) tended to be more abundant in nonfertilized soils and soils amended with composted sludge. These results indicate that sewage sludge modifies the functionality of vegetation when applied to soils, and that the response varies according to the treatment that the sludge has undergone.

Nonlinear response of stream ecosystem structure to low‐level phosphorus enrichment

Summary Anthropogenic inputs of nitrogen (N) and phosphorus (P) create environmental conditions that alter biological organisation and ecosystem functioning in fresh waters. We studied 38 wadeable streams spanning a N and P gradient to contrast responses of algal and fish assemblages to nutrient enrichment. Surface water total P (TP) and total N (TN) concentrations represented a wide range (TP: 7–2380 μg L−1; TN: 127–15 860 μg L−1) and were correlated across our study sites. Total P explained significantly more variance in periphyton carbon (C)‐to‐nutrient (C : P, C : N) and N : P ratios than TN. Abrupt, nonlinear declines in these ratios were observed between 20 and 50 μg L−1 TP and 500–1000 μg L−1 TN; beyond these values, ratios exhibited minimal additional decline. Algae assemblage structure was strongly linked to surface water TP, TN and catchment‐scale nutrient sources (wastewater treatment plant (WWTP) discharges and % pasture cover). In particular, there were synchronous declines in frequency and cell densities of many alga species associated with TP concentrations &gt;21 μg L−1 (90% CI of 18–48 μg L−1) as well as simultaneous increases in tolerant species associated with increasing enrichment. Fish assemblage structure was most strongly associated with % pasture, WWTP discharges and fine sediment cover, yet also showed significant but weaker correlations with surface water and periphyton nutrient variables. However, two benthic fish species, Etheostoma spectabile and Campostoma anomalum, significantly declined with TP &gt;28 μg L−1 (90% CI, 24–56 μg L−1) and 34 μg L−1 (90% CI, 21–56 μg L−1), respectively. Conversely, the tolerant minnow Cyprinella lutrensis and invasive carp Cyprinus carpio increased nonlinearly with increasing surface water TP. Our results provide new insights into interpretation and analysis of assemblage‐level responses to nutrient enrichment. Our findings indicate that a numerical criterion for surface water TP of c. 20 μg L−1 would be needed to maintain natural algae assemblages and at least two specialist fishes within our study region. Proliferation of weedy alga species and increased abundance of invasive fishes are also likely when surface water concentrations exceed these thresholds. While many streams likely exceed these thresholds, managers should consider potential low‐level enrichment effects when developing criteria for ecosystems to protect existing nutrient‐limited streams.

Turf wars: experimental tests for alternative stable states in a two‐phase coastal ecosystem

Alternative stable states have long been thought to exist in natural communities, but direct evidence for their presence and for the environmental switches that cause them has been scarce. Using a combination of greenhouse and field experiments, we investigated the environmental drivers associated with two distinctive herbaceous communities in coastal ecosystems in New Zealand. In a mosaic unrelated to micro-topography, a community dominated largely by native turf species (notably Leptinella dioica, Samolus repens, and Selliera radicans) alternates with vegetation comprising exotic (i.e., nonnative) pasture species (notably Agrostis stolonifera, Holcus lanatus, Lolium perenne, and Trifolium repens). The species of these two communities differ in functional characters related to leaf longevity and growth rate, and occupy soils of differing nitrogen levels. Both spatial and environmental factors influenced the species composition locally. Reciprocal transplants of soil, with and without associated vegetation, showed that a native turf community developed when sward or soil from either community was bounded by turf, and a pasture community developed when sward or soil from either community was surrounded by pasture. In artificial mixed communities in the greenhouse, turf was able to invade the pasture community where the vegetation was clipped to simulate grazing, and also where Trifolium was removed and/or salt spray was applied. The pasture community invaded the turf where Trifolium was present or nitrogen was added. These results were supported by trends in experimentally manipulated field plots, where the amount of turf cover increased when nitrogen was kept low and when salt spray was applied, whereas pasture cover increased in the absence of salt spray. Thus, persistence of the native turf community is dependent on grazing, both directly and via its effect on keeping nitrogen levels low by excluding the exotic, nitrogen-fixing Trifolium, and by exposing the vegetation to salt spray. If any of these factors change, there could be a state change to pasture dominance that might be resistant to reversion to turf. Managing such coastal herbaceous communities therefore requires an understanding of the environmental and species characteristics that maintain alternative states.

HOW LANDSCAPE PATTERNS INFLUENCE ROAD-KILL OF THREE SPECIES OF MAMMALS IN THE BRAZILIAN SAVANNA

Roads are one of the main threats to mammal species conservation. Identifying relationships between landscape and road-kill patterns is necessary to build predictive models and to propose mitigation measures, particularly in heterogeneous landscapes. We choose three species of medium-sized mammals with high dispersal capacity and opportunistic habitat use as representatives to understand which landscape features affect road-kills: the crab-eating fox Cerdocyon thous , the maned-wolf Chrysocyon brachyurus , and the hare Lepus europaeus. The study was done over two consecutive years on the SP-225 highway in the State of Sao Paulo, southeastern Brazil. Road-kill data were collected on a daily basis, every three hours, by car travelling at 50-60 km/h. We used a logistic regression considering, as dependent variable, the occurrence of road-kills for each species, and as independent variables, the following landscape features: sugarcane fields cover, pasture cover, native vegetation cover, forestry cover, orange groves cover, urban area, and distance to the nearest river. Three buffer sizes were created around each road-kill occurrence to evaluate the effect of spatial scale. Model selection using Akaike Information Criterion with correction for small samples (AICc) showed that the road-kill incidence of Chrysocyon brachyurus was positive associated to urban area at larger scale, and for Cerdocyon thous and Lepus europaeus was found a positive association to forestry cover at different scales. For C. thous and L. europaeus , some models worth interpreting included water bodies area, distance to the nearest river and sugarcane fields cover. Matrix permeability and river proximity could be used to indicate sites to apply mitigation measures to road-kill for these mammal species in the Brazilian Savanna.

Factors associated with extended milking intervals in a pasture-based automatic milking system

In pasture-based automatic milking systems (AMS) cow traffic and behaviour are markedly different and generally cows achieve lower milking frequencies (MF, defined here as the number of milking events/cow in a 24h period) and lower milk production levels in comparison to indoor systems. In this study, a total of 151,893 individual milking records collected from the FutureDairy pasture-based AMS research farm during 2007 and 2008 were analysed to examine relationships between cow traffic related variables and cow performance. In addition, factors specific to pasture-based systems, such as proportion of pasture in the diet, pasture allowance, distance to pasture allocation and pre-grazing pasture cover, were explored to understand their association with occurrence of different milking intervals (MI, defined here as the amount of time elapsed between consecutive milking events, measured at every milking session in hours since the previous milking event). Although there was a wide range of MI and MF, higher MI were associated with greater milk yields per milking. Yet, efforts should be focused on reducing the occurrence of MI above 16h, because secretion rate beyond that threshold tended to decrease. Increasing MF was associated with greater daily milk yield for cows in all stages of lactation. Overall, longer MI were observed in late lactation and primiparous cows. Additionally, an increase in distance between the paddock and the dairy up to 500m appeared to be unrelated to a change in MI, but higher MI were observed with distances from the dairy facility between 500m and up to 1km. Pre-grazing pasture covers above 3000kg DM/ha or below 2000kg DM/ha were associated with shorter and longer MI respectively. For every 5kg DM/cow increase in pasture allowance above 10kg DM/cow, there was a 10–15min increase in MI. Modifying management practices to accommodate these factors specific to pasture-based systems could allow for increased MF and higher total milk yield per cow.