Habitat associations and communities of breeding birds in the highlands of south-west Jordan

Abstract

Habitat associations and communities of breeding birds were studied for the first time in a semi-arid region in the southern highlands of Jordan. Birds were censused and habitat variables estimated in different habitat types, ranging from steppe to open, Mediterranean-type woodland. The variation of abundance of several species was explained adequately with multiple regressions of up to five habitat variables. A distinct bird community was identified by using principal component analysis on the highland plateau (e.g. Short-toed Lark, Isabelline Wheatear), in steppe habitats modified by dry farming methods. The plateau was identified as a transition zone of Palaeoxeric/Turkestanian and Mediterranean faunal types. The remainding cluster included species of diverse origins (Palaearctic, Mediterranean, Saharo-Sindian, Afrotropical and others). It was subdivided into three bird assemblages with preferences for following habitat types: Mediterranean-type open woodlands (e.g. Syrian Serin), dwarf shrub formations of higher altitudes (e.g. Spectacled Warbler), dwarf shrub formations, including clearings and the edge of woodlands at lower altitudes (e.g. Scrub Warbler).     

An experimental investigation into the effects of traffic noise on distributions of birds: avoiding the phantom road

Many authors have suggested that the negative effects of roads on animals are largely owing to traffic noise. Although suggestive, most past studies of the effects of road noise on wildlife were conducted in the presence of the other confounding effects of roads, such as visual disturbance, collisions and chemical pollution among others. We present, to our knowledge, the first study to experimentally apply traffic noise to a roadless area at a landscape scale—thus avoiding the other confounding aspects of roads present in past studies. We replicated the sound of a roadway at intervals—alternating 4 days of noise on with 4 days off—during the autumn migratory period using a 0.5 km array of speakers within an established stopover site in southern Idaho. We conducted daily bird surveys along our ‘Phantom Road’ and in a nearby control site. We document over a one-quarter decline in bird abundance and almost complete avoidance by some species between noise-on and noise-off periods along the phantom road and no such effects at control sites—suggesting that traffic noise is a major driver of effects of roads on populations of animals.     

Evaluating the effectiveness of conservation site networks under climate change: accounting for uncertainty

We forecasted potential impacts of climate change on the ability of a network of key sites for bird conservation (Important Bird Areas; IBAs) to provide suitable climate for 370 bird species of current conservation concern in two Asian biodiversity hotspots: the Eastern Himalaya and Lower Mekong. Comparable studies have largely not accounted for uncertainty, which may lead to inappropriate conclusions. We quantified the contribution of four sources of variation (choice of general circulation models, emission scenarios and species distribution modelling methods and variation in species distribution data) to uncertainty in forecasts and tested if our projections were robust to these uncertainties. Declines in the availability of suitable climate within the IBA network by 2100 were forecast as ‘extremely likely’ for 45% of species, whereas increases were projected for only 2%. Thus, we predict almost 24 times as many ‘losers’ as ‘winners’. However, for no species was suitable climate ‘extremely likely’ to be completely lost from the network. Considerable turnover (median = 43%, 95% CI = 35–69%) in species compositions of most IBAs were projected by 2100. Climatic conditions in 47% of IBAs were projected as ‘extremely likely’ to become suitable for fewer priority species. However, no IBA was forecast to become suitable for more species. Variation among General Circulation Models and Species Distribution Models contributed most to uncertainty among forecasts. This uncertainty precluded firm conclusions for 53% of species and IBAs because 95% confidence intervals included projections of no change. Considering this uncertainty, however, allows robust recommendations concerning the remaining species and IBAs. Overall, while the IBA network will continue to sustain bird conservation, climate change will modify which species each site will be suitable for. Thus, adaptive management of the network, including modified site conservation strategies and facilitating species' movement among sites, is critical to ensure effective future conservation.     

Seasonal dimorphism in the horny bills of sparrows

Bill size is often viewed as a species‐specific adaptation for feeding, but it sometimes varies between sexes, suggesting that sexual selection or intersexual competition may also be important. Hypotheses to explain sexual dimorphism in avian bill size include divergence in feeding niche or thermoregulatory demands, intrasexual selection based on increased competition among males, or female preference. Birds also show seasonal changes in bill size due to shifts in the balance between growth rate and wear, which may be due to diet or endogenous rhythms in growth. Insight into the function of dimorphism can be gained using the novel approach of digital x‐ray imaging of museum skins to examine the degree to which the skeletal core or the rhamphotheca contribute to overall dimorphism. The rhamphotheca is ever‐growing and ever‐wearing, varying in size throughout life; whereas the skeletal core shows determinant growth. Because tidal marsh sparrows are more dimorphic in bill size than related taxa, we selected two marsh taxa to investigate dimorphism and seasonality in the size of the overall bill, the skeletal core, and the rhamphotheca. Bill size varied by sex and season, with males having larger bills than females, and bill size increasing from nonbreeding to breeding season more in males. Skeletal bill size varied with season, but not sex. The rhamphotheca varied primarily with sex; males had a larger rhamphotheca (corrected for skeletal bill size), which showed a greater seasonal increase than females. The rhamphotheca, rather than the skeletal bill, was responsible for sexual dimorphism in overall bill size, which was particularly well developed in the breeding season. The size of the rhamphotheca may be a condition‐based character that is shaped by sexual selection. These results are consistent with the evidence that bill size is influenced by sexual selection as well as trophic ecology.     

Hydroxylation of quinocetone and carbadox is mediated by CYP1As in the chicken (Gallus gallus)

Quinoxaline derivatives (quinoxalines) comprise a class of drugs that have been widely used as animal antimicrobial agents and feed additives. Although the metabolism of quinoxaline drugs has been mostly studied using chicken liver microsomes, the biochemical mechanism of biotransformation of these chemicals in the chicken has yet to be characterized. In this study, using bacteria produced enzymes, we demonstrated that both CYP1A4 and CYP1A5 participate in the oxidative metabolism of quinoxalines. For CYP1A5, three hydroxylated metabolites of quinocetone were generated. In addition, CYP1A5 is able to hydroxylate carbadox. For CYP1A4, only one hydroxylated product of quinocetone on the phenyl ring was identified. Neither CYP1A5 nor CYP1A4 showed hydroxylation activity towards mequindox and cyadox. Our results suggest that CYP1A4 and CYP1A5 have different and somewhat overlapping substrate specificity in quinoxaline metabolism, and CYP1A5 represents a crucial enzyme in hydroxylation of both quinocetone and carbadox.     

Effect of mineral oil on Potato virus Y acquisition by Rhopalosiphum padi

Seed potato crops are currently sprayed weekly with mineral oil to prevent transmission of the Potato virus Y (PVY; Potyviridae: Potyvirus), one of the most prevalent and important non‐persistent viruses affecting potato production. In spite of its wide usage as inhibitor of virus transmission, the mode of action for mineral oil is poorly known. The objective of this study was to quantify the effect of dosage and time from application of mineral oil on the inhibition of PVY acquisition. The bird cherry‐oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae), known as vector of PVY, was used in all the experiments. The results indicated that mineral oil efficiently decreased PVY acquisition by 75 and 70% 1 day after application of 5 and 10 l ha^?1, respectively. The inhibition effect decreased with time from application; mineral oil inhibits acquisition for less than 4 days at 5 l ha^?1 and between 8 and 12 days at 10 l ha^?1. As mineral oil was detected in the body of fewer aphids when they fed on plants 1 day after oil application, a change in the aphid probing behaviour on mineral oil‐treated plants was deduced. These results support the hypothesis that mineral oil physically inhibits the binding of the virus at the tip of the stylets.     

A response to Gatali and Wallin (2015) Bird diversity in the savanna habitats of Akagera National Park,Rwanda, in the post-war recovery period

The paper ‘Bird diversity in the savanna habitats of Akagera National Park, Rwanda, in the post-war recovery period’ by Gatali and Wallin (Ostrich 86(3): 267–276, 2015) makes several claims for new species records for Akagera National Park and Rwanda. We found that Gatali and Wallin recorded several species considered very rare in Rwanda and new discoveries; these findings often contradicted the existing literature. We doubt the validity of 34 species records and we aim to demonstrate that these claims are mostly the result of misidentification or human error and consider that future researchers should use their findings with caution. Some findings around more common species may be validated through further studies and we encourage others to conduct fieldwork in Akagera National Park.     

中国鸟类亚种新记录——黑冠黄鹎

2010年12月和2011年4月,分别在广西西北部百色市右江区和靖西县古龙山自然保护区拍摄和观察到黑冠黄鹎(Pycnonotus flaviventris)的johnsoni亚种.其喉部为红色,与中国其他记录亚种区别明显,属中国鸟类亚种的新记录.该文亦初步讨论了该亚种的分类和分布.     

When secondary comes first – The importance of non-canonical DNA structures

Secondary structure-forming DNA motifs have achieved infamy because of their association with a variety of human diseases and cancer. The 3rd FASEB summer conference on dynamic DNA structures focused on the mechanisms responsible for the instabilities inherent to repetitive DNA and presented many exciting and novel aspects related to the metabolism of secondary structures. In addition, the meeting encompassed talks and posters on the dynamic structures that are generated during DNA metabolism including nicked DNA, Holliday junctions and RNA:DNA hybrids. New approaches for analysis and sequencing technologies put forth secondary structures and other DNA intermediates as vital regulators of a variety of cellular processes that contribute to evolution, polymorphisms and diseases.     

The impact of roads on the avifauna of páramo grasslands in Cajas National Park,Ecuador

National parks are an important tool for conserving biodiversity, particularly in areas of high biodiversity and endemism such as the tropical Andes. However, national parks often face a variety of stressors related to recreation, road construction and illegal extraction of natural resources. Unfortunately, the influence of these stressors for biodiversity is rarely well documented. Cajas National Park in Ecuador is no exception. Despite being traversed by the Cuenca-Molleturo-Naranjal road, effects of the road construction on biodiversity have not been determined. We therefore assessed the influence of road proximity on bird species richness and abundance as well as composition of bird habitat groups in Cajas National Park using transect walks at 25 m and 250 m distance to the road (overall 18 transects, each 1 km length). In total, we recorded 1110 individuals of 28 páramo bird species. Overall species richness did not differ between transects near and far from the road. Nevertheless, the average abundance of shrubby páramo species was significantly higher far from the road than near the road (Far = 36, Near = 25). Moreover, we found a tendency towards differences in the composition of bird habitat groups between transects near and far from the road. One aspect potentially driving the observed patterns was the increasing proportion of planted non-native woody tree species within páramo grassland near the road, which may have caused reduced abundances of shrubby páramo bird species there. While roads represented a clear impact on the composition of bird species in the páramo, the major effect seems to be driven by the introduction of non-native plant species along the roadside. In order to reduce the impact of roads to a minimum, we suggest that park managers should control the introduction of such plant species.