Territorial defense and advertisement by footdrumming in bannertail kangaroo rats (Dipodomys spectabilis) at high and low population densities

Summary Behaviors associated with territorial defense of large dirt mounds by bannertail kangaroo rats (Dipodomys spectabilis) at high and low population densities are reported. Rats were observed for 640 h during three summers and one spring from 1980–1982 in SE Arizona.Bannertail kangaroo rats defended their territories by footdrumming, as a long-distance warning signal, and chasing as a closer-distance threat. They footdrummed on or near their mounds spontaneosly during the night, in response to neighbors' footdrums, and durint mound challenges. There were no sexual differences in footdrumming, and juveniles frequently performed the behavior. The low frequency sounds were within the auditory sensitivities of the rats and footdrumming patterns differed somewhat between individuals. A playback experiment provided preliminary evidence that rats can differentiate between the footdrums of neighbors and strangers. When a bannertail visited the mound of another bannertail the mound owner actively defended its mound and immediately chased the visitor away. Fighting and mound challenges occurred infrequently, and the uniformly dispersed distribution of mounds suggested an effort by rats to avoid mutual interference.When population densities were high, dispersing juveniles built new mounds, consequently, distances between mounds decreased. Rats responded by tolerating closer neighbors, spending more time active on their mounds, and visiting neighboring mounds less. Adults increased footdrumming rates at high population densities, but juveniles footdrummed at high rates regardless of the population size.     

Expected,prenatally discovered,and born cases of Down syndrome in Denmark during the period 1980–1998

In order to elucidate the consistency between generally used age-dependent risk values for Down syndrome (DS) and estimates of the probability of miscarriage in Down pregnancies we have compared expected numbers with estimated numbers of births with DS in Denmark had no intervention at all been carried out. The expected numbers were calculated from the distribution of newborn children according to maternal age combined with the age-related risk of DS. The estimated numbers of children that actually would have been born without any intervention were estimated from observed numbers of cases of DS, i.e. the cases born plus – with corrections because of the high probability of miscarriage in DS pregnancies – a proportion of those cases discovered prenatally. The analysis was carried out separately for mothers aged 35 years or older and for younger mothers. We found a high degree of compatibility between expected and estimated numbers, probably with a minor underestimation of the expected values for the older mothers. The performance of DS screening in Denmark in the period under consideration (1980–1998) is discussed in relation to the figures presented. Despite the fact that 11.8% of all pregnancies were subjected to an invasive diagnostic procedure, only about 38% of all births with DS were prevented. This means that in the period 1990–1998, reluctance to accept serological screening has indirectly resulted in the birth of almost 300 cases of DS in Denmark and at the same time the miscarriage of an unreasonable high number of normal fetuses. Copyright © 2001 John Wiley & Sons, Ltd.     

Climate and air quality-driven scenarios of ozone and aerosol precursor abatement

In addition to causing domestic and regional environmental effects, many air pollutants contribute to radiative forcing (RF) of the climate system. However, climate effects are not considered when cost-effective abatement targets for these pollutants are established, nor are they included in current international climate agreements. We construct air pollution abatement scenarios in 2030 which target cost-effective reductions in RF in the EU, USA, and China and compare these to abatement scenarios which instead target regional ozone effects and particulate matter concentrations. Our analysis covers emissions of PM (fine, black carbon and organic carbon), SO₂, NO_x, CH₄, VOCs, and CO. We find that the effect synergies are strong for PM/BC, VOC, CO and CH₄. While an air quality strategy targeted at reducing ozone will also reduce RF, this will not be the case for a strategy targeting particulate matter. Abatement in China dominates RF reduction, but there are cheap abatement options also available in the EU and USA. The justification for international cooperation on air quality issues is underlined when the co-benefits of reduced RF are considered. Some species, most importantly SO₂, contribute a negative forcing on climate. We suggest that given current knowledge, NO_x and SO₂ should be ignored in RF-targeted abatement policies.     

Feather-like development of Triassic diapsid skin appendages

Of the recent sauropsid skin appendage types, only feathers develop from a cylindrical epidermal invagination, the follicle, and show hierarchical branching. Fossilized integuments of Mesozoic diapsids have been interpreted as follicular and potential feather homologues, an idea particularly controversially discussed for the elongate dorsal skin projections of the small diapsid Longisquama insignis from the Triassic of Kyrgyzstan. Based on new finds and their comparison with the type material, we show that Longisquama's appendages consist of a single-branched internal frame enclosed by a flexible outer membrane. Not supporting a categorization either as feathers or as scales, our analysis demonstrates that the Longisquama appendages formed in a two-stage, feather-like developmental process, representing an unusual early example for the evolutionary plasticity of sauropsid integument.     

Cranial pneumatization and auditory perceptions of the oviraptorid dinosaur <Emphasis Type="Italic">Conchoraptor gracilis</Emphasis> (Theropoda,Maniraptora) from the Late Cretaceous of Mongolia

The distribution of air-filled structures in the craniofacial and neurocranial bones of the oviraptorid ZPAL MgD-I/95, discovered at the Hermiin Tsav locality, Mongolia, is restored. Based on the complete obliteration of most of the cranial sutures, the specimen is identified as an adult individual of Conchoraptor gracilis Barsbold 1986. Except for the orbitosphenoids and epipterygoids, the preserved bones of the neurocranium are hollow. Three types of tympanic recess are present in Conchoraptor, a characteristic shared with troodontids, dromaeosaurids, and avian theropods. The contralateral middle ear cavities are interconnected by the supraencephalic pathway that passes through the dorsal tympanic recesses, the posterodorsal prootic sinuses and the parietal sinus. The spatial arrangements of the middle ear cavity and a derived neurocranial pneumatic system in Conchoraptor indicate enhancements of acoustic perception in the lower-frequency registers and of auditory directionality. We further speculate that this improvement of binaural hearing could be explained as an adaptation required for accurate detection of prey and/or predators under conditions of low illumination. The other potentially pneumatic structures of the Conchoraptor cranium include (1) recessus-like irregularities on the dorsal surface of the nasal and frontal bones (a putative oviraptorid synapomorphy; pos); (2) a subotic recess; (3) a sub-condylar recess; and (4) a posterior condylar recess (pos). Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Positive long-term effect of mulching on species and functional trait diversity in a nutrient-poor mountain meadow in Central Europe

Oligotrophic mountain meadows are threatened biodiversity hotspots throughout Europe. The traditional summer hay-making followed by autumn grazing is no longer economic and question is whether alternative managements can maintain both plant species and functional diversity typical of these habitats. In the Bohemian Forest Mts., we applied three treatments (mowing once a year - i.e., cutting and removing the biomass, mulching once a year - cutting and leaving the crushed biomass to decompose in situ, fallowing - no cutting) in order to assess temporal changes in meadow vegetation, plant trait composition and biomass production in a 13-year experiment. We recorded for each species twenty-five traits as to be most informative of plant strategies related to growth, resource acquisition and carbon-water economy. We compared different components of trait composition (community averages that mostly reflect traits of dominant species vs. the Rao index of functional diversity that reflects trait dissimilarity among species) and their impact on biomass production. We show that mulching promotes species and functional diversity by facilitating heliophilous forbs and legumes with more acquisitive strategies in resource use and release, e.g., higher foliar N and P content. This occurs at the expense of tall grasses (with resource-retentive strategies, e.g., high leaf dry matter content) which dominate the mown and fallow plots. The divergence in most quantitative traits indicates that niche complementarity is the dominant assembly process in mulched plots, which can prevent competitive exclusion and enable species coexistence. The divergent development was detected only after 5-6 years. This slow floristic and functional response is caused by acidity of soil and severe mountain climate that preclude rapid responses of vegetation to land-use changes. We conclude that mulching represents a good compromise maintaining both plant species and functional diversity as well as a relatively high biomass production. Mowing without grazing leads to gradual nutrient loss and thus reduces the productivity and diversity in these oligotrophic ecosystems. Fallowing causes gradual loss in diversity by increased grass competition and litter accumulation.     

SWOT Analysis and Challenges of Nile Basin Initiative: An Integrated Water Resource Management Perspective

Abstract

River Nile is one of the longest transboundery rivers and it is shared and used by Burundi, Democratic Republic of Congo, Egypt, Ethiopia, Eritrea, Kenya, Rwanda, Sudan, Tanzania and Uganda. As of today, the Nile is a crucial resource for the economic development of the Nile Basin countries and a vital source of livelihood for 160 million inhabitants as well as 300 million people living in the 10 riparian countries. The Nile Basin Initiative (NBI) is one of the international cooperative river basin management program and regional partnership where all the Nile Basin countries except Eritrea unite to pursue long-term sustainable development, improved land use practices and management. This review therefore focused on the challenges not faced on NBI in terms of integrated use of the river and conducted analysis of strengths, weaknesses, opportunities and threats (SWOT) based on secondary data. The result of the review revealed that for decades, the Nile Basin people have been facing many complex environmental, social, economic and political challenges that have made it difficult for the proper management and sustainability of Nile water. The initiative provides training to develop skills in government ministries, non-governmental organizations and local communities in each country. It is also working to raise awareness of critical environmental issues by strengthening networks of environmental education practitioners; developing curriculum in the education sector. The challenges of NBI include the involvement and funding of World Bank, lack of sufficient staff, procedural and policies conflicts, lack of coordination and linkage with other regional institutions and lack of recognition as river basin organization. Considering the complex nature of the project, it is recommended that the NBI should come up with a strong multi-disciplinary monitoring and evaluation team to follow up all implemented projects. The NBI should carry out participatory land use planning in communities along the river basin. Moreover, livelihood analysis should be carried out especially in communities along the Nile to come up with poverty eradication projects which are socially acceptable, applicable, economically viable and affordable.     

Exploring the potential effect of Achnatherum splendens L.–derived biochar treated with phosphoric acid on bioavailability of cadmium and wheat growth in contaminated soil

Environmental Science and Pollution Research - Biochar remediation efficiency could be enhanced through numerous treatments such as acids treatment. Still, there has little work done on...