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ABSTRACT We evaluated the reproductive losses in three periods: period I - starting from the time the cows were exposed to the bulls to pregnancy diagnoses (PD, number of cows diagnosed as non-pregnant/total exposed cows × 100); period II - from the time of PD to calving (number of calving cows/number of cows diagnosed as pregnant × 100); and period III - from calving to weaning (number of weaned calves/number of calving cows × 100) in purebred Hereford (HH) and Angus (AA) cows and their crosses in beef cows under extensive production systems. Likewise, the effect of parity (nulliparous, primiparous, and multiparous) and the interaction between both factors were studied. A thirteen-year data set (2505 record) of an experimental breeding herd, maintained in an extensive production system based on natural grassland, was used. The dataset was under a complete diallel design between HH and AA breeds. Both the genetic group and parity of the cow affected the reproductive losses, but only in period I. No interaction was found. Purebred cows had higher reproductive losses than the crossbred cows, without differences between the purebred (HH and AA) or between the crossbred (AH and HA). The greatest losses were observed rather in primiparous than in nulliparous and multiparous cows without difference between the latter two. The use of crossbred cows in extensive production systems is an alternative to reduce reproductive losses and to increase calf harvest.

Home to 88 million people, the Ethiopian mountains are a highly heterogeneous landscape. The Afroalpine ecosystem is found above 3000 masl and is characterized by high levels of species diversity, rarity, and endemism. The objective of this article is to investigate impacts of plantation forests on both the human and plant communities of the Afroalpine zone. We use a case study of a community-based conservation area in the north central highlands, Guassa Community Conservation Area (Guassa), where plantation forests have been established since the 1970s. The study area covers about 78 km2 ranging between 2600 and 3700 masl and largely belongs to the Afroalpine zone. We interviewed 100 residents of the 4 administrative regions closest to Guassa and conducted vegetation sampling of 70 quadrats along 2 transect lines. We found a roughly equal number of ecosystem services between native grassland and plantation forest. However, respondents reported 7 unique ecosystem services from the native grassland and only 3 unique ecosystem services from the plantation forest. Both native grassland and plantation areas were valued for their perceived ability to attract rain and provide habitat for wild animals. We recorded a total of 87 species belonging to 63 genera and 31 plant families across both vegetation types surveyed and a total of 19 endemic species. Of the plant families, Asteraceae had the highest species number. Although plantation forests support less diverse plant communities and provide fewer unique ecosystem services to human communities compared to native Afroalpine vegetation, they are still a valuable piece of the landscape mosaic. [ABSTRACT FROM AUTHOR]

Home to 88 million people, the Ethiopian mountains are a highly heterogeneous landscape. The Afroalpine ecosystem is found above 3000 masl and is characterized by high levels of species diversity, rarity, and endemism. The objective of this article is to investigate impacts of plantation forests on both the human and plant communities of the Afroalpine zone. We use a case study of a community-based conservation area in the north central highlands, Guassa Community Conservation Area (Guassa), where plantation forests have been established since the 1970s. The study area covers about 78 km2 ranging between 2600 and 3700 masl and largely belongs to the Afroalpine zone. We interviewed 100 residents of the 4 administrative regions closest to Guassa and conducted vegetation sampling of 70 quadrats along 2 transect lines. We found a roughly equal number of ecosystem services between native grassland and plantation forest. However, respondents reported 7 unique ecosystem services from the native grassland and only 3 unique ecosystem services from the plantation forest. Both native grassland and plantation areas were valued for their perceived ability to attract rain and provide habitat for wild animals. We recorded a total of 87 species belonging to 63 genera and 31 plant families across both vegetation types surveyed and a total of 19 endemic species. Of the plant families, Asteraceae had the highest species number. Although plantation forests support less diverse plant communities and provide fewer unique ecosystem services to human communities compared to native Afroalpine vegetation, they are still a valuable piece of the landscape mosaic.

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: This paper provides a critical analysis of the development and current outcomes of Australia's first endorsed strategic assessment under the Environment Protection and Biodiversity Conservation Act 1999, namely, the Melbourne Strategic Assessment. It covers progress towards protection of a number of Nationally Significant Species and Ecological Communities – most notably, the native grassland communities immediately adjacent to Melbourne's Urban Growth Boundary. The Commonwealth approval to protect biodiversity and allow urban development was made in 2010 and it aimed to achieve its outcomes by 2020. These outcomes included providing new land for homes, for new transport corridors, and for conservation of biodiversity. Natural Temperate Grassland (4,667 ha), Grassy Eucalypt Woodland (709 ha) and seven other Matters of National Environmental Significance will be impacted. Mitigation for this is establishment of 15,000 ha of grassland reserves, 1,200 ha of grassy woodland reserves, over 4,000 ha of other land zoned for conservation and 300 ha of wetland restoration. We conclude that the Melbourne Strategic Assessment has been a success in terms of the elegance and comprehensiveness of the approach, in cooperation between the levels of government, in the economic benefits, and in some aspects of social engagement of the agreement. However, the achievement of environmental outcomes must be currently considered a failure due to poor implementation. This failure includes not meeting the agreed 10 year deadline for land acquisition and management, poor monitoring and protection of set‐aside areas, and in reporting. We offer suggestions for how these current shortcomings could be overcome. These align well with the recommendations of the review of the Environment Protection and Biodiversity Conservation Act 1999 (The independent statutory review of the Act in 2020) and include the establishment of the proposed Office of Compliance and Enforcement, the adoption of National Environmental Standards and the reforms regarding the role of Indigenous Australians in strategic assessments. If these were adopted, we conclude that the strategic assessment approach should be more widely used because of the more holistic approach and efficiencies that it envisages compared with site by site approaches. [ABSTRACT FROM AUTHOR]

ABSTRACT The objective of this study was to verify the association of improved native grassland and winter and summer pastures on the weaning rate in beef cattle production. Subsequently, we also verified the socioeconomic and productive characteristics related to the adoption of technologies to increase the weaning rate of the farmers. The survey was conducted with 73 producers of Hereford and Braford cattle in the state of Rio Grande do Sul, Brazil. A data analysis was performed using the minimum ordinal squares method and the regression analysis (Tobit). The results showed that cattle farmers who adopt winter pastures have greater weaning rates, and the factors that influence this adoption are related to a greater number of employees on the farm and the use of a crop-livestock production system. In addition, farmers who receive a greater number of technical assistance visits per year are more likely to adopt winter pastures and improved native grassland. This information can be useful in the formulation of technological dissemination programs that aim at a sustainable production of beef cattle.

Grassland management aimed at enhancing carbon (C) in soil is an important tool in mitigation of rising atmospheric CO2, yet little is known of how grassland soil C changes with livestock stocking rate (SR). We relate soil organic and inorganic C mass (t ha−1 to 60 cm depth) with cattle stocking over periods of 7–27 year for 32 paddocks distributed across nine community pastures in the mixed‐grass prairie of Saskatchewan, Canada. Initial analysis comparing Akaike information criterion models showed that cattle SR explained a greater proportion of variance in soil C, particularly soil organic C, than rainfall. Soil organic C mass increased with cattle SR (R2 =.293; p =.001), even when the latter was normalized to account for differences in vegetation composition and growing conditions among pastures. Normalized SR varied from 0.49 to 2.30 times recommended levels, over which SOC increased from 24.7 to 57.4 t ha−1. Increases in soil organic C under greater stocking coincided with increased abundance of introduced vegetation, particularly the rhizomatous grass Poa pratensis. Inorganic soil C accounted for 34.6% of total soil C, being particularly large below 30 cm soil depth, but did not vary with stocking rate. These findings indicate that both organic and inorganic C are important pools of C in northern temperate grassland soils, with soil organic C positively associated with long‐term cattle SR. Further studies are recommended to understand more fully the mechanisms regulating grazing impacts on soil C mass in northern temperate grasslands. [ABSTRACT FROM AUTHOR]

Wildlife translocations have been historically plagued by failure. As more species gain endangered status, we must increase the success rate through use of pre‐emptive empirical, evidence‐based research. The main ecological risk is the potential for the relocated individuals to have competitive advantage at the recipient site, acting invasively and, potentially, outcompeting the native fauna for food, shelter or other resources. Here we investigated the ecological risk of increased population density, following a population augmentation of the pygmy bluetongue lizard (Tiliqua adelaidensis) an endangered lizard, endemic to South Australia. We experimentally increased T. adelaidensis density to ascertain if a sudden increase in T. adelaidensis density would negatively affect the abundance or body condition of the resident conspecifics and co‐existing lizard species found at the recipient site. Twenty‐four individuals, from two populations, were relocated into previously built enclosures at a recipient site in grassland habitat, north of Adelaide, South Australia. For one activity‐season pre and post the augmentation, co‐existing lizard species were sampled in an effort to detect any changes inabundance or body condition. Comparisons were also made between experimental enclosures, containing residents and translocated individuals and control enclosures, containing only residents. Using Menetia greyii as a proxy for all of the competing species, our results show there was no reduction in abundance or body condition post augmentation. Our lack of evidence indicating a negative impact of the T. adelaidensis translocation on the body condition and abundance of the resident lizard species is a positive outcome for future conservation of this species. This study provides a new way of approaching wildlife movements, through identification of potential risks using small‐scale translocations in an enclosed area before conducting large‐scale releases into unfenced areas; the results are intended to facilitate higher translocation success rates and limit the negative effects upon the wider ecological community at recipient sites. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Native grassland in North America is considered one of the most imperiled and altered ecosystems. Unfortunately, an assessment of how much native grassland remains in North America is difficult because all nation-wide landcover mapping products do not reliably distinguish native grasslands from grasslands that have been deliberately planted with tame grasses and forbs (i.e., tame grasslands). We established a 218.5 km2 study area in southwestern Saskatchewan, Canada to evaluate the use of high-resolution Light Detection and Ranging (LiDAR) for classification of native (i.e., fields with native-dominant species mixes or fields that were formerly native species dominated but have been invaded by exotic species) and tame grasslands (i.e., grasslands dominated by exotic grass and forb species), and compared these classifications to the best-available landcover mapping product that is currently available for this area. We used the presence of tractor furrows, identified from the LiDAR digital terrain hillshade product, in tame-dominated grasslands to distinguish them from native-dominated grasslands that had an absence of tractor furrows. The LiDAR method achieved substantially better classification success (Cohen's Kappa = 0.57) at distinguishing native-dominated (N = 82) from tame-dominated grasslands (N = 45), than the currently available landcover product (Cohen's Kappa = 0.13) over our 218.5 km2 study area. Misclassification by LiDAR of fields that had been planted with tame grasses and forbs, but were starting to be re-established by native plants appeared to be one weakness of the method in the study area. Our research highlights a novel and time-efficient method for classifying LiDAR imagery using easily available image analysis features in ArcGIS. Highlights • Distinguishing native from tame grasslands is important for grassland conservation. • A new method using LiDAR was developed to identify these two landcover types. • We achieved better classification success than currently available landcover layers. • This technique is novel and time efficient when classifying large areas. [ABSTRACT FROM AUTHOR]

This research was conducted in the municipality of Santiago de Machaca is the first section of the province José Manuel Pando, is located southeast of the department of La Paz, a distance of 205 km, from the city of La Paz, the research objectives were to determine the consumption Flames selected a native pasture and determine the nutritional quality selected (% PC, % NDF,% FDA) Burning of native pasture. The results were: 18 native grasses consumed by the four camels, fodder were identified that more quantity than was consumed Trifolium pratensis (layu layu) No.1 consumed camel, camel No. 2 (473 (462.93 gr.) , 6 g), camel No. 3 (544.43 g) and the camel No. 4 (477.87 g), native grassland and Bromus catharticus (Cebadilla) camélido No.1 consumed (357.12 gr.), camel No. 2 (409,6gr.), camel No. 3 (445,44gr.) and camel No. 4 ( 310,61gr.). The total consumption of 18 forage species based on live weight (Kg.) was next, camel No.1 consumed (1,323 Kg.) (62 Kg. PV), camel No. 2 (1,280Kg.) (60 Kg. PV), camel No. 3 (1,237Kg.) (58 Kg. PV) and camel No. 4 (1,195 Kg.) (56 Kg. PV). The statistical analysis of the four camels, by completely randomized design (ANOVA), is indicating no significant difference (p ≥0.05) with respect to consumption of native grasslands. The samples sent to the laboratory of the Institute of Diagnostic Laboratory Services and Health Research Institute SELADIS were: maximum concentration crude protein found in the pasture Trifolium pratensis (layu layu) 15.93% and is lower Bromus grassland catharticus (Cebadilla) 15.33%; The concentration of neutral detergent fiber (NDF), Bromus grassland catharticus (Cebadilla) has 65.66% and the pasture Trifolium pratensis (layu layu) 45.21%, the concentration is directly related to the type of pasture and composition flora, being the Bromus grassland catharticus (Cebadilla) is enhanced by the structure of cell walls. Grasslands who consume more camels on the geographic location and area of ​​study is the Trifolium pratensis (layu layu) and Bromus catharticus (Cebadilla). The two Trifolium pratensis (layu layu) and Bromus catharticus (Cebadilla) have good nutritional value, relative to the neutral detergent fiber and acid for Trifolium pratensis (Layu layu) is below 60%., Which promotes the consumption of these native grasslands analyzed for Bromus catharticus (Cebadilla) is above 60% this by having greater wall structure that decreases consumption of this forage species.

Highlights • There was a shift of the AMF virtual taxa community in response to disturbance type. • Site disturbance decreased AMF richness. • AMF richness was positively correlated with plant richness. • Eight AMF genera were found on undisturbed sites and three on disturbed sites. • Glomus comprised the majority of virtual taxa. Abstract Native grasslands are endangered by non-native plant invasion worldwide, including foothills fescue grasslands in North America. Large populations of non-native plant species have established in these disturbed fescue grasslands, forming dense monocultures and spreading into undisturbed areas. Soil disturbance and plant invasion can alter the arbuscular mycorrhizal fungi (AMF) community, an important symbiotic partner of most land plants, which could negatively affect native plant reestablishment. The objective of this study was to assess whether AMF communities on a fescue grassland shifted in response to disturbances by landfill storage and gravel quarrying and with invasion of non-native plant species relative to undisturbed grassland. Soil and root-AMF samples were procured from disturbed and undisturbed areas at three sites. Plant canopy cover and species richness were assessed. Soils were analyzed for pH; electrical conductivity; total nitrogen, carbon and phosphorus; and available nutrients. For relative AMF taxa abundance assessment, NS31 and AMF specific primer AML2 were used to amplify a central fragment of the V3 and V4 region of the 18S rRNA gene. AMF were characterized using 454 pyrosequencing and multiplexed barcoded samples amplified from genomic DNA isolated from roots. There were 92 AMF, including 15 potentially novel taxa detected. AMF communities in disturbed and undisturbed sampling locations were distinct except for one site, and indicator AMF virtual taxa (VT) for undisturbed grassland and disturbed sites were identified. AMF richness was higher in undisturbed (72 VT) than disturbed (64 VT) sites and AMF richness was positively correlated with plant species richness, diversity and native plant cover, and negatively correlated with non-native plant cover. There were 43 AMF VT on undisturbed and disturbed sites, 62% with higher relative abundance on disturbed sites. Site disturbance shifted AMF communities relative to undisturbed native fescue grassland; thus restoration success with native plants might be highly dependent on reintroducing native AMF. [ABSTRACT FROM AUTHOR]

Little is known about the specific role of exotic species on measures of grassland plant diversity, including how this may vary with climatic conditions or large mammal herbivory. This study examined vegetation responses to long-term livestock grazing, including plant richness and diversity, as well as the contribution of exotic species to these metrics, across a network of 107 northern temperate grasslands in Alberta, Canada, spanning a broad aridity gradient. Exposure to grazing modestly increased plant richness, but did not alter Shannon’s diversity, Simpson’s diversity, or evenness, suggesting stability in floral diversity relative to grazing. However, grazing did increase grass cover while reducing shrub cover, the latter of which was only apparent in mesic grasslands. Unlike total plant diversity, exotic species richness and cover, together with exotic plant contributions to diversity, varied jointly with grazing and aridity. While long-term grazing increased exotic species, this response was most apparent in wetter areas, and non-grazed grasslands remained more resistant to the presence of exotics. Several exotic species were positive indicators of grazing in wetter grasslands, and coincided with lower native species cover, indicating grazing may be facilitating a shift from native to exotic vegetation under these conditions. Overall, our results indicate that while long-term grazing has altered the composition and cover of certain functional groups, including favoring exotics and minimizing woody vegetation in mesic areas, overall changes to plant diversity were limited. Additionally, these findings suggest that semi-arid northern temperate grasslands remain relatively resistant to grazing effects, including their susceptibility to exotic plant encroachment. These results improve our understanding of how ongoing grazing exposure may impact grassland diversity, including efforts to conserve native vegetation, as well as the important role of climate in altering fundamental grassland responses to grazing. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study undertaken to classify lowland native grassland communities in the Tasmanian Midlands region. Data was collected using the 20 band hyperspectral snapshot PhotonFocus sensor mounted on an unmanned aerial vehicle. The spectral range of the sensor is 600 to 875 nm. Four vegetation classes were identified for analysis including Themeda triandra grassland, Wilsonia rotundifolia, Danthonia/Poa grassland, and Acacia dealbata. In addition to the hyperspectral UAS dataset, a Digital Surface Model (DSM) was derived using a structure-from-motion (SfM). Classification was undertaken using an object-based Random Forest (RF) classification model. Variable importance measures from the training model indicated that the DSM was the most significant variable. Key spectral variables included bands two (620.9 nm), four (651.1 nm), and 11 (763.2 nm) from the hyperspectral UAS imagery. Classification validation was performed using both the reference segments and the two transects. For the reference object validation, mean accuracies were between 70% and 72%. Classification accuracies based on the validation transects achieved a maximum overall classification accuracy of 93.

Many streams and rivers in upland watersheds in southern New Zealand drain into deep, oligotrophic lakes with major aesthetic, recreational and conservation values. We examined the effects of increasing pasture cover and weather-related variables on nitrogen (N), phosphorus (P) and dissolved organic carbon (DOC) concentrations in eight streams draining into Lake Wanaka and hypothesised that (1) DOC and N concentrations would increase with increasing land development, but soil characteristics in the watershed would mediate P input and (2) weather-related factors that increase hydrological connectivity in the landscape would enhance the influx of N and DOC. Agricultural development correlated positively with N and DOC concentrations in stream water, but temperature and soil moisture mitigated the influence of pasture cover on surface-water DOC concentration under very dry or very wet conditions. Weather-related factors did not influence N concentrations in streams. Neither land use nor weather-related conditions correlated with concentrations of dissolved P, possibly reflecting good P-binding in soils and lack of sampling during high-flow events. Our results provided evidence that agricultural development in grassland watersheds increases the concentrations ofNand DOC entering Lake Wanaka, and weather and soil conditions mediate the amount of DOC transferred from soils into streams. [ABSTRACT FROM AUTHOR]

Fire is frequently used in the management of pastures in southern Brazil, but its effects on ground-dwelling ant communities in Brazilian subtropical grasslands is still poorly understood. Here, we compared ant species richness and composition between periodically burned and unburned areas in native grasslands of the Atlantic Forest biome. In total, we found 35 epigeic ant species in burned and unburned areas. There was slightly higher species richness in burned than in unburned areas, independent of the sampling period (season). There was a significant difference in richness over the sampling period (season effect). Species composition varied significantly between the areas, in which nine species (26%) occurred only in burned areas, eight (23%) occurred only in unburned areas, and 18 (51%) occurred in both. Four species showed a significant preference for burned sites (Camponotus crassus, Linepithema humile and two undetermined species of Pheidole and Solenopsis). Although this study did not separate fire effects on ground-dwelling ant communities (due to sampling design), it provides new information regarding subtropical native grasslands that can be used as a baseline for future studies. [ABSTRACT FROM AUTHOR]

The use and management of native grassland for dairy production during the rainy season was studied on two small-scale dairy farms in the highlands of central Mexico. Two stocking rates (2 and 4 cows/ha) and two levels of supplementation with commercial concentrate (4 and 6 kg/cow/day) under grazing were given to 12 milking Holstein cows in a 4 × 4 Latin square design replicated three times in a factorial arrangement. Net herbage accumulation (NHA), sward height, chemical composition, and in vitro digestibility of organic matter were recorded for the grassland, as well as vegetation cover and herbage mass 12 weeks post experiment. Animal performance variables were milk yield and composition, live weight, and body condition score. A partial budget analysis of feeding costs, returns, and margins was calculated. There were no differences between periods for NHA and herbage height and between plots for chemical composition ( P > 0.05). However, there were highly significant differences among periods ( P < 0.01) for organic matter, neutral detergent fibre (NDF), acid detergent fibre, in vitro organic matter digestibility (IVOMD), and estimated metabolisable energy (eME), with highly significant plot × period interactions ( P < 0.01) for NDF, IVOMD, and eME. There were no statistical differences ( P > 0.05) between treatments for milk yield, chemical composition of milk, live weight, or body condition score. Post-experimental vegetation cover was 72 % for both stocking rates, indicating there was no degradation of the grassland. Lower feeding costs were for the low supplementation treatments. It is concluded that a high stocking rate in studied native grasslands of 4 cows/ha with moderate concentrate supplementation supports a mean milk yield of 11.9 kg/cow/day during the rainy season without deleterious effects on the grassland. [ABSTRACT FROM AUTHOR]

As condições pedoambientais promovem alterações nos atributos do solo. Sendo assim, o objetivo deste trabalho foi estudar as interferências dos pedoambientes nos atributos do solo de uma topossequência de transição Campos/Floresta na região de Humaitá, AM. Escolheu-se uma topossequência característica de sequência Campos/Floresta, em seguida foi estabelecido um caminhamento, partindo do ambiente de campo natural até o ambiente de floresta. Esses pedoambientes foram identificados e delimitados conforme a expressão dos padrões vegetacionais. Foram coletadas 20 amostras laterais ao caminhamento, representativas de cada uma das unidades pedoambientais da topossequência (campo alto: 0,0-14 e 0,30-0,66 m; campo baixo: 0,0-0,15 e 0,27-0,80 m; zona de ecótono: 0,0-0,15 e 0,32-0,50 m; floresta: 0,0-0,15 e 0,67-100 m), totalizando 80 amostras. O critério de escolha das profundidades foi a coincidência com os horizontes diagnósticos superficiais e subsuperficiais determinados na descrição morfológica dos perfis. Foram realizadas análises físicas de textura, argila dispersa e grau de floculação, densidades do solo e das partículas, porosidade total e condutividade hidráulica. Nas análises químicas foram determinados pH em água e KCl, Ca, Mg, K, Na e Al trocáveis, P disponível, H+Al e C orgânico. Os atributos físicos e químicos do solo apresentaram-se dependentes dos pedoambientes. Com o uso das técnicas estatísticas multivariadas foi possível distinguir três diferentes ambientes que equivalem a três pedoambientes.The pedoenvironmental conditions promote changes in soil properties, so the aim of this work was to study Interference of the pedoenvironment on soil properties in a topossequence of the Grassland/Forest transition in the Humaitá region, AM. Was picked up a topossequence characteristic sequence Grassland/Forest, then a pathway was established, from a field environment to the natural forest environment. These pedoambients were identified and defined as the expression patterns of vegetation. Were collected 20 samples at the representative side of the profiles in each one of the pedoambiental units of the topossequence (top grassland: 0.0-14 and 0.30-0.66 m;low grassland : 0.0-0.15 and 0.27-0.80 m; ecotone zone: 0.0-0.15 and 0.32-0.50 m; forest: 0.0-0.15 m 0.67-100 as a total of 80 samples) being the criteria for sampling depths the coincidence with the surface and subsurface diagnostic horizons determined by the morphological description of the profiles. Were performed physical analysis of texture, clay dispersion and flocculation, soil bulk density and particle porosity and hydraulic conductivity. In the chemical analysis were determined pH in water and KCl, Ca, Mg, K, Na and Al contents, available P, H + Al and organic carbon. The physical and chemical soil were dependent on the pedoambients. With the use of multivariate statistical techniques was possible to distinguish three different environments that are equivalent to three pedoambients.

Extensas áreas de campo nativo do sudoeste do Rio Grande do Sul são suscetíveis ao processo de arenização, que ocorre em áreas de fragilidade pedológica, tendo influência de interferência antrópica e fatores abióticos. Com o objetivo de testar a variação da cobertura vegetal e a dinâmica da arenização no tempo e conforme a influência da distância da encosta, foi desenvolvido um estudo florístico e fitossociológico em áreas de campo nativo sob pastejo. Duas subáreas, diferentes quanto ao processo da arenização, foram selecionadas no município de São Francisco de Assis, RS. O levantamento florístico apontou a ocorrência de 102 espécies, distribuídas em 25 famílias. No estudo fitossociológico, 35 quadros permanentes de 0,25 m² em cada subárea foram dispostos em diferentes distâncias da encosta do morro. Foram registradas as coberturas das espécies vegetais, do mantilho e do solo exposto em três períodos. Dados sobre riqueza e diversidade de espécies e formas de vida foram avaliados por análise de variância, via testes de aleatorização, considerando o fator temporal e o espacial (distância da encosta). Houve maior redução da diversidade específica e da cobertura vegetal na subárea 1 (com menor cobertura vegetal) conforme a variação temporal. Na subárea 2 (com maior cobertura vegetal), o aumento do solo exposto e a conseqüente redução da cobertura vegetal tiveram maior influência da distância da encosta. A alteração da cobertura vegetal e a expansão da arenização observadas ao longo do tempo são resultado da influência conjunta da dinâmica pluviométrica, do tipo solo, da presença de encostas dos relevos tabulares com pouca vegetação e da contínua pressão de pastejo.Extensive areas of native grassland in southwestern Rio Grande do Sul are susceptible to sandy desertification, which occurs in pedologically fragile areas influenced by anthropic interference and abiotic factors. A floristic and phytosociological study was carried out in grazed native grasslands to test vegetation cover variation and sandy desertification dynamics over time and according to the influence of slope distance. Two sub-areas that differed as to the sandy desertification process were selected in São Francisco de Assis municipality, Rio Grande do Sul. The floristic survey revealed the presence of 102 species, distributed in 25 families. For the phytosociological study, 35 permanent plots (0.25 m² each) in each sub-area were arranged at different distances from the hillside slope. Cover of plant species and litter, and bare soil were recorded for three periods. Richness, species diversity, and life forms were evaluated by analysis of variance using randomization tests, considering temporal and spatial factors (slope distance). Higher reduction of species diversity and vegetation cover in sub-area 1 (with less vegetation cover) occurred due to temporal variation. In sub-area 2 (with more vegetation cover), the increase in bare soil and a subsequent reduction of vegetation cover were highly influenced by slope distance. Vegetation cover change and sandy desertification expansion observed throughout this period resulted from the joint influence of rainfall dynamics, soil type, presence of tableland slopes with little vegetation, and constant grazing pressure.

O experimento foi desenvolvido em área de pastagem nativa representativa da transição entre a Serra do Sudeste e a Depressão Central do Rio Grande do Sul, onde as espécies indesejáveis foram representadas especialmente por carqueja (Baccharis trimera (Less.) DC.), caraguatá (Eryngium horridum (Spreng.) Less.) e alecrim (Vernonia nudiflora Less.). Foram avaliados os efeitos iniciais de dois métodos de controle de espécies indesejáveis (até 60 dias após aplicação) sobre a produção de forragem, a dinâmica da vegetação e a eficiência de controle: sem-controle; controle mecânico; e controle químico (herbicida comercial à base de Picloram [64 g/L] + 2,4-D [240 g/L], na dosagem de 5 L do produto comercial/ha). Os tratamentos foram arranjados em um delineamento em blocos ao acaso, com quatro repetições. A massa gramíneas verdes secas e a massa total de MS não diferiram entre os métodos de controle. Foram obtidos valores de 587,9; 472,0 e 0 kg de MS com o controle mecânico, o controle químico e sem-controle, respectivamente, o que comprova influência do método de controle sobre a massa de forragem de leguminosas. A eficiência de controle das espécies indesejáveis, em comparação à ausência de controle, foi de 76,2% para o controle químico e 27,9% para o controle mecânico. A eficiência de controle de espécies, sob aspectos de freqüência dos componentes da pastagem, evidenciou que o controle mecânico não foi eficiente aos 60 dias após aplicação no controle de plantas de alecrim no segundo toque (-27,7%) e plantas de caraguatá no primeiro toque (-30,0%).The study was conducted in a representative native pasture area in the transition between the Serra do Sudeste and Depressão Central of RS. The main undesirable species were represented by: carqueja (Baccharis trimera (Less.) DC.), caraguatá (Eryngium horridum (Spreng.) Less.) and alecrim (Vernonia nudiflora Less). It was evaluated the initial effect (until 60 days after application) of two methods of controlling undesirable plants on forage production, vegetation dynamics, and control efficiency: T1 - without control (control, SC), T2 - mechanical control (mechanic control, CM) and T3 - chemical control (commercial herbicide composed by Picloram (64 g/L) + 2.4-D (240 g/L), in the dosage of 5 L commercial product/ha, CQ). The treatments were organized in a complete block design, with four replications. There were no differences among treatments for the green dry matter of grasses and total DM. The forage legume biomass differed among treatments, with values of 587.9, 472.0 and 0 kg/ha of DM in the CM, CQ and SQ, respectively. The control efficiency of undesirable species in this study was 76.2% for CQ and 27.9% for CM when compared to SC. The species control efficiency, in terms of frequency of pasture components, showed that the CM treatment was not efficient at 60 days after treatment application in the control of Vernonia nudiflora (Alecrim) in the second touch (-27.7%) and Eryngium horridum (Caraguatá) in the first touch (-30.0%).

A monitored population of the critically endangered Plains-wanderer ( Pedionomus torquatus) on Victoria's Northern Plains declined by over 90% between 2010 and 2012 following an unusually wet year which led to flooding, excess grass growth and a major change in the structure of native grasslands. The Plains-wanderer population remained very low on private land during 2013 and 2014 when dry conditions prevailed and domestic stock overgrazed most of its favoured grasslands on red soil. Numbers also remained very low on public reserves despite grassland structure gradually improving there by 2014. In 2015, the population partially recovered in some grasslands protected from overgrazing. Grassland structure is critically important for Plains-wanderer conservation. The 'golf ball technique' proved to be a quick and effective method for measuring grassland structure; it offers a means of accelerating responses to habitat change because it can be easily used by land managers. [ABSTRACT FROM AUTHOR]

A recently purchased private reserve of high conservation value has been grazed in summer by cattle since the early nineteenth century. We ask whether the cattle are causing continuing damage and whether they are necessary to maintain any conservation values. We used five-year-old exclosures to determine the effects of cattle on wetland vegetation, mapped damage to soils and landforms and mapped cattle dung deposition in relation to the distributions of rare and threatened plant species. Cattle impacts on wetland plants were minor. Cattle damage to landforms by pugging and bank collapse was frequent near unfenced water bodies. Rare and threatened species were largely on well-drained ground, while cattle dung was concentrated in wetlands and near water bodies. We conclude that cattle grazing is impacting some conservation values and is not necessary for conservation purposes. Destocking should be accompanied by careful monitoring of threatened plant populations. If necessary, alternative planned disturbances can provide regeneration niches for rare and threatened plants. [ABSTRACT FROM AUTHOR]

We examined patterns of shifting cropland cultivation in the US Great Plains from the dust bowl to the beginning of the twenty-first century, by comparing land-cover data from 400 sample sites across the region from the 1930s, 1950s, 1970s, 1990s and 2000s. The small area land-cover data were nested within 50 target counties across the region. To understand the use of marginal land for cultivation since the Great Depression, we argue, requires consideration of the long term dynamics of demography, technology and policy. We draw on these historical dynamics, and their interactions with programs aimed at reducing environmental impacts of agriculture, to tell the story of how and when marginal lands have been brought into use. In a multilevel panel design, macro- and micro-level covariates were used to predict levels of encroachment on marginal soils. We conclude that land retirement programs (like the Conservation Reserve Program) have had a generally stabilizing effect on the micro-level patterns of land use in recent decades, but that increased levels of encroachment on marginal soils and native grassland remain a problem in areas with higher or increasing population densities. [ABSTRACT FROM AUTHOR]

Aims: The principal objective was to evaluate the interference by the invasive species, H. pilosella, on native grassland species at the physiological performance level. We hypothesised that the invasive species is able to alter the nitrogen uptake of native plant species, and can modify community functioning. Methods: This study was performed under field conditions in the Magellanic Steppe (Argentina). We compared stable isotope signatures, nutrient content and several functional physiological traits in four grassland species with and without H. pilosella interference. Results: We found significant interference effects from the invasive species on native species, mostly through changes in nitrogen uptake. The variation in the natural abundance of foliar δN suggests that the native plants switched nitrogen sources due to interference with the exotic species. A linear relationship between chlorophyll and proline content that disappears when species are under H. pilosella interference, suggests major changes in the N allocation of native species. Grassland species under interference with exotic species exhibit lower photochemical efficiency and higher water use efficiency. Canonical discriminant analysis evidenced the existence of a different set of functional traits between invasive and native plants, and also among native species with and without H. pilosella interference. Conclusions: Our results support the hypothesis that H. pilosella exerts intense interference with native species through shifting the N sources available for native species, a lower leaf N content, and increasing water stress. [ABSTRACT FROM AUTHOR]

Leaf appearance rate and phyllochron are related variables which play a central role in forage production. Phyllochron is the time interval between the appearance of successive leaves and varies according to a number of environmental factors, among which temperature is the most important. The experiment was conducted in natural pasture with the aim of testing phyllochron variation under different seasons, herbage allowances, and topographic positions. Marked tillers were used to define the phyllochron, establishing a relationship between the number of leaves produced against thermal time during the sampling period. The time (expressed in °C) needed for the emergence of a leaf is equal to 1/b, where b is the slope coefficient of the regression. The lines for the season combinations, herbage allowances and topographic positions sampled were compared. Under Spring and Summer conditions, the phyllochrons for P. notatum and C. selloana were 156°C and 238°C respectively, regardless of treatment.A taxa de aparecimento de folhas (TAF) e o filocrono são conceitos associados, que exercem forte influência na produção de forragem. O filocrono é o intervalo de tempo entre o aparecimento de duas folhas sucessivas acima do pseudocaule e varia de acordo com alguns fatores ambientais, sendo a temperatura o fator determinante. O experimento foi conduzido em pastagem natural em Eldorado do Sul, RS, com o objetivo de testar a variação no filocrono em diferentes estações do ano, níveis de oferta de forragem (NOF) e posições topográficas (PT). Para a definição do filocrono, foram amostrados perfilhos marcados e estabeleceu-se a relação entre número de folhas produzidas e a soma térmica do período amostral. A soma térmica (em °C) necessária para que a planta emita uma folha é igual a 1/b, sendo b o coeficiente angular verificado na regressão. As retas obtidas para as combinações entre estações, NOF e PT foram comparadas. Em condições de primavera e verão, se obteve filocrono de 156°C para P. notatum e de 238°C para C. selloana, independentemente dos tratamentos avaliados.

Floristic dissimilarity and indicator species of Araucaria Forest and ecotones. The search for knowledge about the expansion of forests in relation to associated ecosystems (native grassland and wetland) addresses the presence of environmental factors such as fire and grazing, often described as determinants of ecological processes in favor of succession dynamics. The objective here was to verify if there are differences among the floristic composition of the interior of forest fragments and transition sectors of forest-native grassland and forest-wetland, as well as to identify indicator species for each of these environments. The research was conducted in forest fragments located in the municipalities of Bom Jardim da Serra and Lages (Coxilha Rica), SC, where we installed two permanent plots of 50x50 m, subdivided into sectors of 10x10 m categorized into three sectors: Araucaria Forest, forest transition x native grassland and forest x wetland transition. There is floristic dissimilarity between the local forest fragments and also between the transition areas (ecotones). The indicator species of ecotones are linked to early stages of forest succession, with potential for colonization of the field, they can operate in the start of the expansion of the forest boundary process. [ABSTRACT FROM AUTHOR]

Currently, livestock management in the North American Great Plains aims for even use of forage, which creates a homogenous landscape. Reintroducing heterogeneity, defined here as the variation in vegetation structure and composition, to native North American rangelands is imperative to maintaining grassland biodiversity, and using a variety of cattle stocking rates on the landscape could accomplish this. We assessed effects of stocking rates on northern mixed-grass prairie vegetation structure, structural heterogeneity, and plant species diversity. The study took place in Grasslands National Park in Saskatchewan, Canada, using nine pastures (∼300 ha) that were grazed at a range of stocking rates from very low to very high for this region. Three of these pastures were ungrazed controls. We used generalized linear mixed models to describe effects of stocking rate on vegetation over 4 years, following the reintroduction of livestock grazing to this landscape after 15 years without grazing. We used a Mantel test to determine whether plant communities changed with varying stocking rates and over time. Effects of grazing on many response variables were cumulative and changed over time. Species richness in uplands increased with stocking rate and time, but richness decreased with stocking rate in lowlands. Heterogeneity generally increased with stocking rate and time in upland but not lowland habitats. While natural annual variability influenced many variables, the cumulative effects of grazing were still apparent. A variety of stocking rates could be used to maximize structural heterogeneity and provide a diversity of habitat structure at the landscape scale. [ABSTRACT FROM AUTHOR]

The importance of animal production in the overall context of human activity is undisputed and influences food supply, job security, income producing, as well as landscape and local ecosystems conservation. This relevance enhances the charges by society as the environmental impacts of various activities, especially in relation to ruminant production amid the current problems of climate changes. In this context, we analyzed the main environmental impacts of two typical beef cattle production systems from southern Brazil, namely the extensive system (ES) and the improved system (IS), and identified the components that have the greatest environmental impacts using the life cycle assessment method. The basis of the system construction was a cattle herd that originated from 100 weaned heifers, four weaned calves, and the progeny of these cattle during their productive life (12 years), and the land areas, external inputs, and other natural resources and technologies necessary to the operations. The functional unit was the production of 1 kg of live weight. The values of greenhouse gas emissions, land use, and freshwater depletion in the ES were higher compared with those values obtained for the IS (22.52 and 9.16 kg CO 2 equivalents; 234.78 and 21.03 m 2 a; and 0.217 and 0.0949 m 3 , respectively). These variations were attributed to the permanence time of the animals in each system and to the quality and production of the pastures. The ES presented lower potential impacts than the IS on metal depletion and soil acidification (0.000519 and 0.0536 kg Fe equivalents; and 0.0028 and 0.0038 kg SO 2 equivalents, respectively) mainly due to the pasture improvement practices and the salt supply to the animals. Moreover, the values of freshwater eutrophication and fossil depletion were higher in the ES than in the IS (0.00383 and 0.00219 kg P equivalents and 0.0042 and −0.1255 kg oil equivalents, respectively). While the pasture nutrient loss from runoff and leaching defined the values of eutrophication, the introduction of legumes compensates the use of fossil fuels. The diversity of the results provides a better understanding of the environmental impacts of different production systems and of regional singularities. [ABSTRACT FROM AUTHOR]

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Summary Soil moisture is a critical state variable affecting a variety of land surface and subsurface processes. Despite the complex interactions between soil moisture and its controlling factors, the phenomenon of temporal stability of soil moisture ( TS SM ) has been widely observed under natural conditions. In this study, the control of vegetation on TS SM is investigated by artificially manipulating surface vegetation (e.g., vegetated and de-vegetated plots) in a native grassland-stabilized sand dune area with similar soil texture and topography. Soil moisture data were collected at the depths of 30 cm (within the root zone) and 110 cm (below the root zone) over a period of four years. Using soil moisture data from the de-vegetated plots as a baseline, TS SM within the root zone is shown to be mainly affected by vegetation phenology at the study site. Therefore, the control of vegetation on TS SM varies on both seasonal and annual time scales. The change in the interseasonal patterns of TS SM is tightly related to plant phenology and the control of vegetation on the ranking of mean relative difference ( MRD ) of soil moisture significantly weakens during non-growing seasons due to diminished root water uptake. It suggests that the timing of sampling schemes (e.g., growing season vs. non-growing season) may alter TS SM patterns. On annual time scales, TS SM is affected by climatic conditions, as the control of vegetation on TS SM becomes stronger under drier conditions. In particular, vegetation tends to create larger contrasts in soil moisture levels between vegetated and de-vegetated plots in drier years. The soil moisture data also provide evidence that vegetation tends to reduce TS SM and increase spatial variability in soil moisture at the study site. The standard deviation of relative difference ( SDRD ) of soil moisture at the 30 cm depth (within the root zone) is considerably larger in the vegetated plots than those in the de-vegetated plots. As such, the effectiveness of using representative locations for monitoring mean soil moisture conditions in the vegetated plots deteriorates. [ABSTRACT FROM AUTHOR]

Recent public policies in favor of family farming in Uruguay face a lot of tension with the dominant neoliberal logic of Uruguayan agriculture. This paper analyzes the public policy innovations in the management of natural resources, land use and rural development decentralization. It also examines their effects, especially on the area of family livestock farming. Uruguay is in the process of integrating international standards in environmental policies (conservation of water and soil) and regional sustainable development. But the implementation of new regulatory instruments (territorial, environmental, land use, etc.) has problems as they come in tension or conflict with the interests of the corporate sector or with the identity of family farmer. [ABSTRACT FROM AUTHOR]

O presente estudo objetivou avaliar modificações ocorridas na vegetação em uma área de campo natural, após oito anos sem influência de pastoreio. A área situa-se na Estação Experimental Agronômica da UFRGS, no município de Eldorado do Sul, RS, onde foram realizadas amostragens em 1984 e 1992. Dezesseis unidades amostrais permanentes de 0,25 m² foram utilizadas para verificar a presença e o valor de cobertura das espécies, pela escala de Daubenmire. São apresentados os valores de freqüência e cobertura absolutas (FA e CA, respectivamente) das espécies de Gramineae, Compositae, Rubiaceae, Leguminosae, Umbelliferae e Cyperaceae nos levantamentos de 1984 e 1992. O trabalho evidenciou a relação entre a forma biológica das espécies predominantes e os estados pastejado ou excluído. Em Gramineae, espécies rasteiras, estoloníferas ou rizomatosas (Paspalum notatum, Axonopus affinis e outras), características da área pastejada, foram substituídas por plantas de hábito cespitoso (Andropogon lateralis, Elyonurus candidus e outras), capazes de sombrear e sobrepujar as de baixo porte. Espécies de compostas e rubiáceas, de um modo geral, apresentaram uma redução em FA e pouca alteração em CA. As leguminosas apresentaram principalmente um aumento em FA, mantendo a CA praticamente constante. As umbelíferas destacaram-se pelo aumento da CA em metade de suas espécies. Ocorreu o surgimento de 25 e o desaparecimento de 42 espécies em 1992.The aim of this study was to evaluate modifications after eight years without grazing in a native grassland area, located at the Estação Experimental Agronômica - UFRGS, in Eldorado do Sul, RS. Vegetation surveys were done in 1984 and 1992. Sixteen permanent sample quadrats (0.25 m²) were established and presence of species and cover-abundance values according to the Daubenmire scale were recorded. Absolute frequencies and cover values (AF and AC, respectively) in 1984 and 1992 are presented for Gramineae, Compositae, Rubiaceae, Leguminosae, Umbelliferae and Cyperaceae species. The study showed the relation between the growth forms of the most abundant species and the grazed and ungrazed situations. Creeping, stoloniferous and rhizomatous species of Gramineae (Paspalum notatum, Axonopus affinis and others) were conspicuous when the area was under grazing, being replaced by tussock-type plants (Andropogon lateralis, Elyonurus candidus and others) able to dominate and shade out small understory herbs, when excluded. Compositae and Rubiaceae species showed a reduction in AF and few changes in AC. Leguminosae species had an increase in AF, presenting almost constant values for AC. Half of the Umbelliferae species presented an increase in AC in the second survey. Twenty five species appeared and 42 vanished in 1992.

The supply of pasture quantity and quality in areas of native grassland is goal of ranchers. In this study we evaluated the impact of three grazing intensities by beef cattle in an area of unspoilt countryside with improved white clover and red cloveron soil bulk density (Bd), pre-consolidation pressure (sp), compression index (Ci) and the relaxation index (Ri) in a Vertisol derived from basalt. The experiment was conducted in an area of unspoilt countryside with improved white clover and red clover, subjected to three intensities of grazing, located in the experimental field of INIA Glencoe, in the Centre-North of Uruguay (Latitude: 32º41'S and Longitude: 56º16'W). The soil has a depth of 0.92m, clayey silt (0.58kg kg-1 clay) and has granular structure. The intensity of grazing configured the treatments: no grazing (SP), grazing with low load (consisting of grazing animals per hectare from 20 to approximately 385kg of body weight, during 4 days) (PCB) and grazing with high load (40 animals per hectare of approximately 385kg live weight, during 4 days) (PCA). Statistical analysis consisted of comparing averages of Bd, sp, Ci and Ri in the three soil treatments by Student's t test at 5% of significance. PCA caused no increase in relation to the Ds SP nor significant changes sp and Ic, indicating that the bulk of the organic material provided on the surface of Vertisoil high load bearing capacity, low compaction susceptibility and high elasticity of the soil. The most superficial layer of Ri with respect to subsurface conditioned more resilient deformation, because the PCA were no significant changes in sp and Ic against the SP and PCB. [ABSTRACT FROM AUTHOR]

Agriculture and wildlife conservation programs have converted vast amounts of cropland into grasslands planted with exotic species. Understanding how landscape context influences avian use of native and planted grasslands is essential for developing effective conservation strategies in agricultural landscapes. Our primary objective was to determine the extent to which the amount and type of grassland in the surrounding landscape influences the abundance of grassland songbird species on native and planted grassland parcels in southern Saskatchewan and Alberta, Canada. Bird abundance was more strongly influenced by the amount and type of grassland within 400 m of breeding parcels than at larger spatial scales. Grassland specialists responded similarly to habitat and landscape type over both years and provinces. Sprague's pipit ( Anthus spragueii) and Baird's sparrow ( Ammodramus bairdii) were most common in native grassland parcels surrounded by native grassland and were more likely to occur in planted grasslands surrounded by native grassland. Bobolinks ( Dolichonyx oryzivorus) were most common in planted grassland parcels, but their abundance increased with the amount of native grassland surrounding these parcels. Our findings indicate that the suitability of planted grasslands for these species is influenced by their proximity to native grassland. Grassland generalists showed mixed responses to habitat and landscape type over the 2 years (Le Conte's sparrow [ Ammodramus leconteii]) and between provinces (Savannah sparrow [ Passerculus sandwichensis] and western meadowlark [ Sturnella neglecta]). Management to benefit grassland specialists should therefore consider the landscape context when seeding cultivated land to non-native grassland and conserve extant native grassland. © 2013 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines drivers of land-cover change in the U.S. Great Plains in the last half of the twentieth century. Its central aim is to evaluate the dynamics of grassland preservation and conversion, across the region, and to identify areas of grassland that were never plowed during the period. The research compares land-cover data from 400 sample areas, selected from and nested within 50 counties, to aggregate data from the agricultural and population censuses. The spatially explicit land-cover data were interpreted from aerial photographs taken at three time points (1950s, 1970s and 2000s). Sample areas were chosen using a stratified random design based on the Public Land Survey grid with in the target counties, in several clusters across the region. We modeled the sequences and magnitudes of changes in the interpreted air photo data in a multi-level panel model that included soil quality and slope of sample areas and agricultural activities and employment reported in the U.S. Censuses of Agriculture and Population. We conclude that land retirement programs and production subsidies have worked at cross purposes, destabilizing micro-level patterns of land use in recent decades, increasing levels of switching between cropland and grassland and reducing the size of remaining areas of native grassland in the U.S. Great Plains. [Copyright &y& Elsevier]

Abstract: The Ernest Henry Mine in north west Queensland, Australia, is required to return disturbed land to native grassland and has been undertaking extensive revegetation of waste rock dumps since 2002. To ascertain the trajectories for revegetation success of these rehabilitated native grasslands, annual vegetation monitoring of both rehabilitation sites and selected reference areas has been undertaken since 2007. Long-term monitoring efforts have included assessments of vegetation composition, ecological structure and function at four rehabilitation areas (1–7 years post-rehabilitation) and proximal reference sites within surrounding grazed and ungrazed agro-ecosystems, undisturbed by mining. Our findings demonstrated that the oldest rehabilitated sites had similar species composition and functional elements to selected reference sites, although plant cover and biomass (particularly of native grasses) was lower than both grazed and ungrazed reference areas. The youngest sites had little established vegetation, however species richness was similar to the reference sites and functional life forms were present despite being in very low abundance. It is suggested that future monitoring events and informed management inputs (which consider local climatic conditions and soil fertility factors) could contribute to the development of a stable and sustainable native grassland thus achieving the desired end land use on these post-industrial landscapes. [Copyright &y& Elsevier]

The article offers information that both intraspecific spatial aggregation and temporal priority effects have the potential to increase long term species coexistence. It states intrasepecific aggregation can facilitate coexistence by limited dispersal or asymmetric interaction distance. Temporal priority effects may represent an underappreciated pathway by which intraspecific aggregation can increase coexistence. Restorationists can maintain diverse communities by planting monospecific patches.

The article discusses the results of a study on the compositional changes of short-term native grassland after the application of liquid hog manure. The study shows a decline in plant diversity in mixed native grasslands but an increase in fescue grassland after application of manure. It also mentions the tolerance of native grassland communities to liquid hog manure. The authors suggest the need to be cautious in using native grasslands for manure disposal.

Abstract: Loss and degradation of native grasslands on the North American landscape are some of the key factors influencing population declines of grassland songbirds. It is unclear what role anthropogenic grasslands play in the conservation of grassland specialists and whether demographic parameters of grassland songbirds differ between anthropogenic and native grasslands. Furthermore, there has been little research examining the overlap (or lack thereof) between nesting and post-fledging habitat. We initiated a radio-telemetry study from 2004 to 2008 on dispersal, microhabitat use, and survival of juvenile Sprague’s pipits (Anthus spragueii), a threatened grassland-obligate songbird, in native pastures and fields planted with exotic species (planted grasslands). Dispersal distance was greater in planted compared to native grasslands, but appeared to be constrained to natal fields up to 26-d post-fledging. Pipits used microhabitats in planted grasslands with vegetation that was on average 11cm taller than used locations in native pastures, possibly due to the rapid growth of planted vegetation by the time individuals fledged. Individuals that were reared in planted grasslands had consistently lower daily survival rates compared to those in native pastures. Our observation that young birds rarely left their natal field suggests that conserving nesting habitat in native pastures would be an effective management strategy for this species. However, our results suggest that planted grasslands may act as population sinks given the lower survival of juvenile pipits reared in planted fields in our region. Demographic studies during the post-fledging period are essential to determine the conservation value of anthropogenic grasslands for North American songbirds. [ABSTRACT FROM AUTHOR]

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Copyright of Biociências is the property of EDIPUCRS - Editora Universitaria da PUCRS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil carbon sequestration is a viable short-term option to mitigate increased atmospheric CO2. In agriculture, strategies to increase the soil carbon (C) sink include no-tillage, cover crops, and improved crop rotation. The objective of this study was to determine the influence of tillage systems on SOC and total N, soil aggregation and aggregate associated C and N in three soil types: Oxisol (Brazil), Vertisol (Argentina), and Mollisol (USA). Long-term tillage experiments included tilled (T) and no-till (NT) systems. A native grassland was included for comparison in each site. Soil samples were taken at 0–5, 0–15, and 15–30 cm depths. Water-stable aggregates (WSA) were separated using a wet-sieving method. Total C and total N were determined by dry combustion. A shift from native grassland to an agroecosystem decreased microbial biomass, but this decrease was less pronounced under NT. Cultivation reduced the mass of macroaggregates and the concentration associated C and N; however among agroecosystems, NT, regardless soil type, tended to be more similar to the native grassland sites. Agroecosystems reduced TOC and total N stocks, regardless of soil type, compared to the native grassland. This effect followed: Mollisol > Oxisol > Vertisol, and was more pronounced at the 0–5 cm soil depth than at deeper depths. This loss of C and N was associated with the decrease in the mass of macroaggregates and lower C and N concentrations of the aggregates. Macroaggregation was related to TOC and microbial biomass in the Mollisol, suggesting that the biological process of aggregate formation is the principal mechanism of C protection in these soils. The relationship between TOC and large macroaggregates showed lower values for the Oxisol and Vertisol, indicating that in these soils TOC has a complementary role in macroaggregation. [ABSTRACT FROM AUTHOR]