Ecophysiology and Management Response of the Subtropical Grasslands of Southern South America

The subtropical grasslands of Southern South America (campos) are located approximately in the range of 24° S to 37° S latitude. These grasslands are dominated by C3 and C4 grasses, and in a lesser extent to herbaceous plants, shrubs and dispersed trees, with some exceptions in particular regions. Previous to the introduction of large herbivores, at the beginning of the XVII century, like cattle and horses, shrubs and tall grasses dominated the vegetation. Then, associated with greater grazing pressure and partially due to fire, the original campos are maintained, actually in a pseudo-climax herbaceous phase. These native communities are highly stable, adapted to long periods of water stress and flooding. Campos are generally grazed at continuos stocking all year around by sheep, cattle and horses. With the exceptions of the secondary plant successions, the summer growing species (C4) dominate the campos vegetation, having a high relative frequency (75%). Continuos grazing and coarse summer grasses contribute to decrease the frequency of winter species (C3). There is a high spatial and temporal variation in the native communities related to the type of soil, texture, water capacity, topography, altitude, management, etc., which determinate the different proportions of vegetation types and botanical compositions. The temporal variation is mainly associated with climatic factors, principally rainfall, affecting the variability of the annual dry matter production of campos vegetation (CV = 40 to 50%). The range of annual forage production of campos vegetation varies between 2.5 (shallow and low fertility soils) to 7.0 ton DM ha-1 (deep and fertile soils). Most of the annual forage production is mainly concentrated in spring and summer, reaching 70-80% and 60-70% in shallow and deep soils, respectively. Grazing management, and particularly the stocking rate utilised, is the principal factor determining changes in the botanical composition in this type of vegetation. In general, the use stocking rates greater than 1 stock unit ha-1, for longer periods, causes reductions in forage production, associated with increases and decreases in the frequency of productive species and weeds/shrubs/forbs, respectively. Pasture degradation is even greater, when high stocking rates are applied in conjunction with the use of high sheep/cattle ratios (e.g. 5:1). The use of rotational grazing systems enhances pasture production by 12% as well as pasture utilisation. When continuos stocking is applied, it is difficult to achieve pasture utilisation greater than 50%. Avoiding overgrazing in degraded vegetation, it is possible to obtain a recovery in pasture conditions, while the degradation caused by continuous cropping is unrecoverable. Animal production is negatively affected when herbage mass or sward height are lower than 1000 kg DM ha-1 or 5-6 cm, respectively. Animal selectivity allows sheep and cattle to have a greater crude protein (33 and 22% respectively) and metabolisable energy (15 and 11% respectively) levels than those obtained in the pasture offered. The use application of low quantities of nitrogen and phosphate on native vegetation increase forage production and nutritive value by 50%, enhancing the contribution of winter species (C3) in the sward. Legume introduction by overseeding increases native pasture production by 60-100% and pasture nutritive value by 50-100%, particularly during winter. This response is associated with the contribution of the introduced species and additionally by the increments in proportions of the native winter species (C3), resulting in a higher plan community biodiversity. Improved pastures permit to obtain 4 to 5 times greater secondary production than those unimproved. The generated scientific knowledge has contributed to apply better pasture management practices, which resulted in biological and economical benefits to the farmer community and the whole society in the longer time, with special care of animal and plant communities biodiversity and water conservation for human and animal use. Both animals and plants will be for a long time our main source of food and fibre in the world, hence conditioning our actions and behaviour in the manner that we conserve our natural resources for the future generations

Productivity and Composition of Two Improved Native Pastures under Different Grazing Managements in Uruguay

Two improved native pastures were established by phosphoric (P) fertilisation and oversowing of: white clover (Trifolium repens) mixed with birdsfoot trefoil (Lotus corniculatus) (TbL) and annual lotus (Lotus subbiflorus) (Rin). Such pastures were evaluated during 5 years with steers at two stocking rates (High and Low) and two grazing managements (Rotational and Alternate). Presence of legumes was high and botanical changes were favourable in both pastures that evidenced good persistence. Daily liveweight gains of steers and total animal production were high in both pastures, but significantly (P≤ 0.05) higher in TbL. No significant differences were found due to grazing management. High stocking rate resulted in superior (P≤ 0.05) animal production per hectare than Low. No significant interactions were detected

Effect of Winter Grazing Management of Stockpiled Native Pastures of Basaltic Soils of Uruguay on Daily Gains of Heifers

The effect of three grazing systems of fall stockpiled native pastures on the winter gains of 66 Hereford heifers (135 kg) was studied. Treatments were: continuos grazing (CG); (C7) the plot was divided in 12 and each was grazed for 7 days and (C28), the plot was divided in 3 and each were grazed for 28 days. Heifers were weighed every 14 days and grazing behaviour was recorded. Stockpiled HM was greater (P\u3c 0.05) in C7 and C28 than in CG (988, 912, and 604 kg DM/ha, respectively). Herbage allowance (HA) was greater (P\u3c 0.01) in CG followed by C28 and C7 (11.7, 6.6 and 5.9 kg DM/100 kg LW, respectively). Post-grazing HM was greater (P0.05) in all pastures (CP 10.2%, NDF 71.2%, ADF 41.3% and ash 14.4%). Final LW of heifers were similar (P\u3e 0.05) (167, 162 and 160 kg for CG, C7 and C28, respectively). A very mild winter favoured exceptional gains which tended to be higher in CG (0.353 kg/day) than in C7 (0.305 kg/day) and C28 (0.278 kg/day). Grazing time was greater (P\u3c 0.05) in CG and bite rate was lower in C28 than in C7 and CG heifers. Grazing management did not affect daily gains. Nevertheless, total remaining HM in C28 and more so in C7 more than doubled that in CG, where more animals could have grazed with increasing total productivity

A Sheep and Catlle Diet Selection Study on a Fertilized Native Sward in Uruguay

This study was undertaken during winter, spring and summer 1997, located in the basaltic region of Uruguay to evaluate the effects of stocking rate (SR) and N and P fertilizer application on sward characteristics and on sheep and cattle diet selection and grazing behaviour. The treatments applied were: a) control (C; without fertilizer application using a SR of 0.9 stock units (SU)/ha), b) T1 (with N and P fertilizer application using a SR of 0.9 SU/ha), c) T2 (with N and P fertilizer application using a SR of 1.2 SU/ha) and d) T3 (with N and P fertilizer application using a SR of 1.5 SU/ha). In general, compared with C, fertilized treatments resulted in increments in sward surface height (SSH) and sheep bite weight (BW): a) winter (3, 8, 5 and 5 cm., P \u3c 0.01; 79, 142, 139 and 92 mg DM/bite, P \u3c 0.05), b) spring (3, 8, 5 and 6 cm., P \u3c 0.01; 108, 188, 115 and 215 mg DM/bite, P \u3c 0.01), and c) summer (7, 14, 11 and 8 cm., P \u3c 0.01;146, 199, 182 and 131 mg DM/bite, P \u3c 0.05) for C, T1, T2 and T3, respectively. In general, the nutritive value of diet selected by sheep and cattle was higher than that of the pasture on offer, and higher in sheep than in cattle: a) winter (17, 18 and 16% crude protein, CP, P \u3c 0.05; 39, 37 and 41% acid detergent fiber, ADF, P \u3c 0.05), b) spring (11, 14 and 11% CP, P \u3c 0.05; 42, 33 and 37% ADF, P \u3c 0.01), and c) summer (8, 10 and 9% CP, P \u3c 0.05; 50, 40 and 45% ADF, P \u3c 0.01) for pasture on offer, sheep and cattle diets, respectively. This study demonstrated the importance of fertilizing native swards to improve production, structure, nutritive value, and animal carrying capacity and animal performance. It also shows the important role that diet selection plays in determining the nutritive value of the forage eaten by sheep and cattle, and stresses the greater selective ability of sheep over cattle

A Comparative Grazing Study of Sheep and Cattle Diet Selection on Native Pastures in Uruguay

An experiment was carried out during winter, spring and summer 1997, on native pastures of the basaltic region of Uruguay to evaluate the effects of different herbage mass levels (high, medium and low) on sward characteristics and on sheep and cattle diet selection and grazing behaviour. Higher herbage masses resulted in increments in herbage accumulation and sheep bite weight: winter (1880, 1513 and 610 kg DM ha-1, P \u3c 0.01; 199, 148 and 128 mg DM/bite, P \u3c 0.01), and summer (3046, 2175 and 1172 kg DM ha-1, P \u3c 0.01; 214, 175 and 143 mg DM/bite, P \u3c 0.01) for high, medium and low herbage mass levels respectively. The nutritive value of diet selected by sheep and cattle was higher than that of the herbage on offer, and higher in sheep than in cattle: winter (10.2, 15.9 and 12.5% crude protein, CP, P \u3c 0.05; 49.2, 32.4 and 38.1% acid detergent fiber, ADF, P \u3c 0.01, and summer (7.4, 10 and 9.5% CP, P \u3c 0.05; 51.1, 36.8 and 43% ADF, P \u3c 0.01) for herbage on offer, sheep and cattle diets respectively. These contrasting results found in the nutritive value were closely associated with differences in the proportions of the botanical components recorded, particularly the differential contribution of dead material. This experiment quantified the importance of diet selection in determining the nutritive value of the forage eaten by sheep and cattle on the native pastures of the basaltic region of Uruguay and established some relationships between diet selection and grazing management, involving animal selectivity ability differences (sheep versus cattle) and seasonal effects

Residential energy efficiency interventions: A meta-analysis of effectiveness studies

BACKGROUND: The residential sector releases around 17% of global greenhouse gas emissions and making residential buildings more energy efficient can help mitigate climate change. Engineering models are often used to predict the effects of residential energy efficiency interventions (REEI) on energy consumption, but empirical studies find that these models often over-estimate the actual impact of REEI installation. Different empirical studies often estimate different impacts for the same REEI, possibly due to variations in implementation, climate and population. Funding for this systematic review was provided by the evaluation function at the European Investment Bank Group. OBJECTIVES: The review aims to assess the effectiveness of installing REEIs on the following primary outcomes: energy consumption, energy affordability, CO2 emissions and air quality indices and pollution levels. SEARCH METHODS: We searched CAB Abst, Econlit, Greenfile, Repec, Academic Search Complete, WB e-lib, WoS (SCI and SSCI) and other 42 databases in November 2020. In addition, we searched for grey literature on websites, checked the reference lists of included studies and relevant reviews, used Google Scholar to identify studies citing included studies, and contacted the authors of studies for any ongoing and unpublished studies. We retrieved a total of 13,629 studies that we screened at title and abstract level, followed by full-text screening and data extraction. SELECTION CRITERIA: We included randomised control trials, and quasi-experimental studies that evaluated the impact of installing REEIs anywhere in the world and with any comparison. DATA COLLECTION AND ANALYSIS: Two independent reviewers screened studies for eligibility, extracted data and assessed risk of bias. When more than one included study examined the same installation of the same type of REEI for a similar outcome, we conducted a meta-analysis. We also performed subgroup analyses. MAIN RESULTS: A total of 16 studies were eligible and included in the review: two studies evaluated the installation of efficient lighting, three studies the installation of attic/loft insulation, two studies the installation of efficient heat pumps, eight studies the installation of a bundle of energy efficiency measures (EEMs), and one study evaluated other EEMs. Two studies, neither appraised as having a low risk of bias, find that lighting interventions lead to a significant reduction in electricity energy consumption (Hedges' g = −0.29; 95% confidence interval [CI]: −0.48, −0.10). All the other interventions involved heating or cooling, and effects were synthesizised by warmer or colder climate and then across climates. Four studies examined the impact of attic/loft insulation on energy consumption, and two of these studies were appraised as having a low risk of bias. Three studies took place in colder climates with gas consumption as an outcome, and one study took place in a warmer climate, with the electricity consumption (air conditioning) as the outcome. The average impact across all climates was small (Hedges' g = 0.04; 95% CI: −0.09, 0.01) and statistically insignificant. However, two of the studies appear to have evaluated the effect of installing small amounts (less than 75 mm) of insulation. The other two studies, one of which was appraised as low risk of bias and the other involving air conditioning, found significant reductions in consumption. Two studies examined the impact of installing electric heat pumps. The average impact across studies was not statistically significant (Hedges' g = −0.11; 95% CI: −0.41, 0.20). However, there was substantial variation between the two studies. Replacing older pumps with more efficient versions significantly reduced electricity consumption in a colder climate (Hedges' g = −0.36; 95% CI, −0.57, −0.14) in a high risk of bias study. However, a low risk of bias study found a significant increase in electricity consumption from installing new heat pumps (Hedges' g = 0.09; 95% CI, 0.06, 0.12). Supplemental analyses in the latter study indicate that households also used the heat pumps for cooling and that the installed heat pumps most likely reduced overall energy consumption across all sources—that is, households used more electricity but less gas, wood and coal. Seven studies examined bundled REEIs where the households chose which EEMs to install (in five studies the installation occurred after an energy audit that recommended which EEMs to install). Overall, the studies estimated that installing an REEI bundle is associated with a significant reduction in energy consumption (Hedges' g = −0.36; 95% CI, −0.52, −0.19). In the two low risk of bias studies, conducted with mostly low-income households, installed bundles reduced energy consumption by a statistically significant amount (Hedges' g = −0.16; 95% CI, −0.13, −0.18). AUTHORS' CONCLUSIONS: The 16 included studies indicate that installing REEIs can significantly reduce energy consumption. However, the same type of REEI installed in different studies caused different effects, indicating that effects are conditional on implementation and context. Exploring causes of this variation is usually not feasible because existing research often does not clearly report the features of installed interventions. Additional high quality impact evaluations should be commissioned in more diverse contexts (only one study was conducted in either Asia or Africa—both involved lighting interventions—and no studies were conducted in South America or Southern Europe)

Effect of Stocking Rate and Grazing System on Fine and Superfine Merino Wool Production and Quality on Native Swards of Uruguay

Modern textile tendencies show that consumers prefer light, soft, resistant, natural, and comfortable clothes, for which fine and superfine wools are in great demand, particularly at the high value markets (Whiteley, 2003). The main objective of the present study was to define sustainable stocking rates and grazing systems on native swards for fine and superfine wool production in the Basaltic region of Uruguay

PROTOCOL: Residential energy efficiency interventions: An effectiveness systematic review

This review aims to identify, appraise and synthesise the evidence available on the effectiveness of energy efficiency measure installations, including those bundled with behavioural interventions. The synthesis will estimate the overall impact of these interventions as well as examine possible causes of variation in impacts. We will also attempt to assess the cost-effectiveness of residential energy efficiency interventions

Amphetamine-evoked c- fos mRNA expression in the caudate-putamen: the effects of DA and NMDA receptor antagonists vary as a function of neuronal phenotype and environmental context

Dopamine (DA) and glutamate neurotransmission is thought to be critical for psychostimulant drugs to induce immediate early genes (IEGs) in the caudate-putamen (CPu). We report here, however, that the ability of DA and glutamate NMDA receptor antagonists to attenuate amphetamine-evoked c- fos mRNA expression in the CPu depends on environmental context. When given in the home cage, amphetamine induced c- fos mRNA expression predominately in preprodynorphin and preprotachykinin mRNA-containing neurons (Dyn-SP+ cells) in the CPu. In this condition, all of the D1R, D2R and NMDAR antagonists tested dose-dependently decreased c- fos expression in Dyn-SP+ cells. When given in a novel environment, amphetamine induced c- fos mRNA in both Dyn-SP+ and preproenkephalin mRNA-containing neurons (Enk+ cells). In this condition, D1R and non-selective NMDAR antagonists dose-dependently decreased c- fos expression in Dyn-SP+ cells, but neither D2R nor NR2B-selective NMDAR antagonists had no effect. Furthermore, amphetamine-evoked c- fos expression in Enk+ cells was most sensitive to DAR and NMDAR antagonism; the lowest dose of every antagonist tested significantly decreased c- fos expression only in these cells. Finally, novelty-stress also induced c- fos expression in both Dyn-SP+ and Enk+ cells, and this was relatively resistant to all but D1R antagonists. We suggest that the mechanism(s) by which amphetamine evokes c- fos expression in the CPu varies depending on the stimulus (amphetamine vs. stress), the striatal cell population engaged (Dyn-SP+ vs. Enk+ cells), and environmental context (home vs. novel cage).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66272/1/j.1471-4159.2003.01815.x.pd