Search results for "GRASSLAND"

Flora and vegetation of pastures utilized by the Sicilian Black Pig of the Nebrodi Mountains (NE Sicily).

2007

High emissions of greenhouse gases from grasslands on peat and other organic soils

2016

Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site-averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO2 -eq. ha-1  yr-1 ) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO2 (27.7 ± 17.3 t CO2  ha-1  yr-1 ) dominated the GHG budget. Nit…

Daurian pikas ( Ochotona daurica ) and grassland condition in eastern Mongolia

2003

Pikas ( Ochotona spp.) are burrowing herbivorous mammals believed to play a keystone role in determining the biodiversity of steppe ecosystems. Impacts of domestic livestock grazing on the distribution and abundance of the Daurian pika Ochotona daurica were investigated in eastern Mongolia where the species is widespread and abundant. Effects of pikas on plant species richness and vegetation coverage were examined at different distances from burrow systems. Daurian pikas were nearly absent from severely grazed study sites, and incidence of the species increased with decreasing grazing intensity. The number of occupied burrow systems and usage of burrows was higher in sites with lower grazin…

Flux heterogeneity and evapotranspiration partitioning in a sparse canopy: the fallow savanna

1997

Abstract This paper focuses on in situ measurements obtained during the intensive observation period of the HAPEX-Sahel experiment. Micrometeorological measurements and trunk sap flow monitoring were combined to analyse transfer characteristics of a fallow savanna site within the East Central Supersite. Results show that the shrub canopy heterogeneity induces a large spatial variability of solar irradiance, soil heat flux and sensible and latent heat fluxes at the grassland level. This variability is induced by both a “shade effect” and a “wake effect”. Both shrubs and grassland provide sources of vapour, but the partitioning of evapotranspiration between these two components varies conside…

Effects of mountain grassland maturity stage and grazing management on carotenoids in sward and cow's milk

2006

Carotenoids are involved in the sensorial and nutritional values of dairy products. In grazing systems, both herbage maturity stage and grazing management may affect the amount of carotenoid ingested, thus these factors may affect carotenoid concentrations in milk. Two homogenous plots of mountain grassland (1.4 and 2.0 ha) were grazed during two cycles of growth by 6 dairy cows in mid lactation, in strip (SG) and rotational grazing (RG), respectively. We monitored the changes in carotenoid concentrations in sward and milk, measured by HPLC twice a week. Seven carotenoids were identified in the sward: violaxanthin, antheraxanthin, epilutein, lutein, zeaxanthin, ß-carotene and 13-cis ß-carot…

Massive migration from the steppe was a source for Indo-European languages in Europe

2015

We generated genome-wide data from 69 Europeans who lived between 8,000-3,000 years ago by enriching ancient DNA libraries for a target set of almost four hundred thousand polymorphisms. Enrichment of these positions decreases the sequencing required for genome-wide ancient DNA analysis by a median of around 250-fold, allowing us to study an order of magnitude more individuals than previous studies and to obtain new insights about the past. We show that the populations of western and far eastern Europe followed opposite trajectories between 8,000-5,000 years ago. At the beginning of the Neolithic period in Europe, ~8,000-7,000 years ago, closely related groups of early farmers appeared in G…

Simulated poaching affects global connectivity and efficiency in social networks of African savanna elephants-An exemplar of how human disturbance im…

2022

Selective harvest, such as poaching, impacts group-living animals directly through mortality of individuals with desirable traits, and indirectly by altering the structure of their social networks. Understanding the relationship between disturbance-induced, structural network changes and group performance in wild animals remains an outstanding problem. To address this problem, we evaluated the immediate effect of disturbance on group sociality in African savanna elephants—an example, group-living species threatened by poaching. Drawing on static association data from ten free-ranging groups, we constructed one empirically based, population-wide network and 100 virtual networks; performed a …

Grasslands and Shrublands of the Mediterranean Region

2020

The Mediterranean Region extends to the 1.6% of the world’s land surface and more than the half of the Mediterranean-type ecosystems of the world. The remarkable species richness in the Mediterranean Region mainly originates from an exceptional habitat diversity and the presence of several natural barriers facilitating the segregation and differentiation of local taxa and biocoenoses. In this article, we deal with the habitats characterized by grasslands and shrublands that clearly show the adaptations to what could be called “the Mediterranean syndrome”, i.e., the intrazonal Mediterranean grasslands and shrublands (MG&S). The main driving forces of the adaptive radiation and high biodi…

Abrupt vegetation changes in the Segura Mountains of southern Spain throughout the Holocene

2001

Summary 1 The fossil pollen record of Canada de la Cruz in the Segura mountains of southern Spain yields insights into high-elevation vegetational dynamics over the last c. 8320 years. Phases of xerophytic grassland alternate with high-mountain open pine forests and expansion of deciduous forests and Mediterranean scrub at lower altitudes. 2 Longer-term stable vegetation patterns are interrupted by multidecadal to century-scale shifts at about 7770, 3370, 2630, 1525 and 790 years BP. 3 Some of the vegetation types have no modern analogues and represent high-altitude remnants of widespread last-glacial xerophytic communities. Other species patterns, characteristic of current scrub associatio…

Soil aggregate stability under different Mediterranean vegetation types

1998

The influence of vegetation type on soil erodibility was studied by means of aggregate stability measurements using the Modified Emerson Water Dispersion Test (MEWDT), water-drop impacts (CND and TDI) and Ultrasonic Disruption (UD) methods on soils from north-facing slopes of the mountain range of La Serra Grossa in the eastern Iberian Peninsula. Soils with similar characteristics but covered by the main plant species at the study area were selected. Quercus ilex woodland showed the most resistant soil aggregates followed by Q. coccifera and Pistacea lentiscus scrubland, Brachypodium retusum grassland and Pinus halepensis woodland. Aggregates developed beneath dwarf shrubs like Rosmarinus o…