Patterns of territory settlement and consequences for breeding success in the Northern Wheatear Oenanthe oenanthe

We examined the pattern of territory settlement and its consequences for breeding success in the Northern Wheatear Oenanthe oenanthe on Bardsey Island, Wales, during the breeding seasons of 1991-93. Males returned earlier than females, and older males returned earlier than first-year breeders. Although their boundaries shifted between years, the general location of territories was consistent during the three-year study. There was a high degree of fidelity to area and territory between years for both sexes. The order of territory settlement, from which a territory rank was calculated, was highly consistent for males between years irrespective of individual settlement patterns and territory fidelity. Patterns of territory settlement were less predictable for females, although there was a significant correlation between the mean territory ranks of paired males and females. There was a male-biased sex ratio in each year, and between 5% and 26% of males remained unpaired throughout the breeding season. Male mating status and breeding success were dependent on arrival date, territory rank and breeding density. Early-arriving, usually older, males were able to settle on territories first and were more likely to pair, while later-arriving individuals were more likely to remain unmated. These effects were consistent between years, and consequently territories could be classified as either preferred (accounting for proportionately more breeding attempts) or non-preferred. Territory quality as opposed to individual quality appeared to explain much of the variation in breeding success, and both sexes benefited by breeding on preferred territories through enhanced breeding success and an increased probability that their offspring would be recruited to the population.     

Fertility Control in Free-Ranging Elk Using Gonadotropin-Releasing Hormone Agonist Leuprolide: Effects on Reproduction,Behavior, and Body Condition

ABSTRACT Overabundant elk (Cervus elaphus) populations have become a significant problem in many areas of North America. This is particularly true for protected areas where high densities of elk can cause long-term ecological degradation. When lethal control is not acceptable in these environments, resource managers must often consider alternative methods for reducing the size of resident elk populations. A potential management alternative is controlling the fertility of female elk. A promising new approach to wildlife contraception involves the use of biodegradable implants containing the gonadotropin-releasing hormone (GnRH) agonist leuprolide. During fall 2002-spring 2004, we compared pregnancy rates, reproductive behavior, daily activity patterns, and body condition of 17 free-ranging female elk treated with a leuprolide formulation with 17 untreated females, in Rocky Mountain National Park, Colorado, USA. After treatment, the pregnancy rate of treated elk was 0%, whereas 79% of control elk became pregnant. The effects of treatment were reversed the subsequent year with the pregnancy rate of treated females 100% compared with 91% for controls. Reproductive behaviors were similar for treated and control elk during the breeding and postbreeding seasons; treated elk did not exhibit postrut reproductive behaviors. Moreover, we found no differences in daily activity patterns of experimental groups during the breeding or postbreeding seasons. Treated elk did not show improved body condition over pregnant females. Instead, treated females catabolized proportionately more body fat during winter after treatment and at a higher rate than pregnant control elk. However, this effect was reversed the next spring with no difference in body fat between treated and control elk. We conclude from this experiment that leuprolide, administered as a controlled release formulation, offers a safe and effective method of controlling fertility in free-ranging female elk. However, practical application is limited by treatment duration and the need to treat females before the breeding season.     

Identification of 13 polymorphic microsatellite loci in the zebra finch,Taeniopygia guttata (Passeridae,Aves)

Polymorphic microsatellite loci were identified in order to determine paternity in a captive population of the zebra finch, Taeniopygia guttata. Primer sets from 93 published passerine microsatellite sequences were tested for cross‐species amplification. Thirteen loci were found to be polymorphic, of which, eight displayed null alleles and one locus (Ase50) was found to be Z‐chromosome linked.     

A NEW PIPINE FROG FROM AN EOCENE CRATER LAKE IN NORTH-CENTRAL TANZANIA

Abstract:  The fossiliferous site of Mahenge, Tanzania, interpreted as a small lake that formed in a kimberlite intrusion, has yielded a vertebrate assemblage that includes scarce frog remains. Radiometric dating of the pipe indicates that the volcanic activity took place at 45·83 ± 0·17 Ma, whereas infilling of the crater was completed in 0·2–1·0 myr after emplacement. The frogs, described herein, are preserved as partially articulated skeletons that represent a new pipine taxon, Singidella latecostata gen. et sp. nov. A parsimony analysis of fossil and extant pipoid frogs indicates that Singidella is more closely related to African Hymenochirus and Pseudhymenochirus than to South American Pipa . It also provides weak support for the sister-group relationship of Singidella and the bizarre Late Cretaceous Pachycentrata taqueti (replacement name for Pachybatrachus taqueti ) from Niger, although the incomplete preservation of Pachycentrata precludes thorough comparisons. This record indicates that prior to the rifting in the Miocene the distribution of pipines extended into eastern Africa where they do not occur today.     

Impacts of climatic stability on the structural and functional aspects of macroinvertebrate communities after severe drought

1. Unpredictable, extreme climatic events (e.g. droughts) can potentially destabilize aquatic communities. From 1998 to 2002, southwestern Georgia, U.S.A., experienced the third worst drought of the last 100 years, leading to loss of surface flow in many small streams. We sampled macroinvertebrates, flow and water chemistry in small headwater streams from 2001 to 2007 in two adjacent coastal plain streams of contrasting headwater type (wetland and groundwater‐fed seep) following resumption of flow. 2. Decreasing water temperature, conductivity and nutrient concentrations within the first 2 years of the study indicated flushing of the streambed associated with increased discharge. Invertebrate community composition became less variable over time and during wetter years, reflecting water chemistry, hydrological and climate conditions. 3. A core set of species appeared immediately following breaking of the drought in both streams, reflecting a shared species pool. These species exhibited resilience traits, including short life cycles and resistance to desiccation, which allowed for rapid recovery from disturbance. Such species, which were small‐bodied, sclerotized and abundant in the drift, were then replaced as flows increased by those that were larger, soft‐bodied and rare in drift, suggesting a more stable and less ephemeral habitat. 4. Hydrologic regime and long‐term precipitation indices were strongly correlated with invertebrate community and trait structure. Long‐term data allowed for better interpretation of the effects of infrequent disturbances on aquatic ecosystems. Additionally, long‐term precipitation indices (i.e. 48‐month standardized precipitation index) can indicate the likelihood of a return to drought, allowing for the collection of pre‐disturbance data.     

Phylogeny and systematics of the bee genus Osmia (Hymenoptera: Megachilidae) with emphasis on North American Melanosmia: subgenera,synonymies and nesting biology revisited

The predominantly Holarctic bee genus Osmia Panzer is species‐rich and behaviourally diverse. A robust phylogeny of this genus is important for understanding the evolution of the immense variety of morphological and behavioural traits exhibited by this group. We infer a phylogeny of Osmia using DNA sequence data obtained from three nuclear genes (elongation factor 1‐α, LW‐rhodopsin and CAD) and the mitochondrial gene COI. Our taxon sampling places special attention on North American members of the subgenus Melanosmia Schmiedeknecht; we discuss the novel placement of a number of species traditionally assigned to O. (Melanosmia) and examine the relative support for alternative classifications of this species‐rich subgenus. We use this new phylogeny to guide a reassessment of morphological and behavioural characters within Osmia. Our results provide support for the recognition of Osmia (Hapsidosmia), subgen.n ., a monotypic subgenus containing Osmia iridis Cockerell & Titus. We synonymize Osmia (Mystacosmia) Snelling under O. (Melanosmia), syn.n . We synonymize Osmia (Acanthosmioides) Ashmead under O. (Melanosmia), syn.n ., propose ‘odontogaster species group’ as a replacement for the subgeneric name Acanthosmioides, and refine the morphological characters that serve to diagnose the species group. We additionally propose ‘nigrifrons species group’ for a clade within O. (Melanosmia) containing most species formerly placed in Osmia (Centrosmia) Robertson. We demonstrate more cohesive patterns of nest substrate use in the nigrifrons and odontogaster species groups than was previously believed to occur, reconsider character polarity of aspects of the female mandible, and show that a large number of morphological characters have evolved convergently within the genus. In order to facilitate discussion of relevant taxa, we propose the following 15 new synonymies: O. bakeri Sandhouse under O. melanopleura Cockerell; O. crenulaticornis Michener under O. pinorum Cockerell; O. claremontensis Michener under O. sedula Sandhouse; O. cockerelli Sandhouse under O. dakotensis Michener; O. francisconis White under O. enixa Sandhouse; O. hurdi White under O. austromaritima Michener; O. sladeni Sandhouse under O. nifoata Cockerell; O. titusi Cockerell under O. phenax Cockerell; O. subtrevoris Cockerell, O. physariae Cockerell, and O. erecta Michener under O. giliarum Cockerell; and O. universitatis Cockerell, O. integrella Cockerell, O. amala Cockerell, and O. metitia Cockerell under O. nigrifrons Cresson, syn.n . We remove O. wyomingensis Michener from synonymy with O. nifoata Cockerell, stat.n ., and O. pinorum Cockerell from synonymy with O. physariae Cockerell, stat.n . This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:A3E7D63B‐5C4C‐4ACF‐BF33‐48E5C5DD1B0D .     

Major Biological Issues Resulting from Anthropogenic Disturbance of the Nitrogen Cycle

A two-day Discussion Meeting of the Royal Society, 'The Nitrogen Cycle', held in London in June 1991 (Stewart & Rosswall, 1992) reviewed the considerable progress made in understanding the N cycle in agricultural, forest and aquatic systems. The meeting included some discussion of the concerns which were already being expressed at that time over nitrate in water supplies, and the impacts of nitrogenous gases on tropospheric chemistry, the greenhouse effect and the ozone layer. Since then, disquiet over the impacts of nitrogenous compounds on the environment has increased, and numerous papers have been published on many aspects of the problem. We now have much better understanding of the size and scale of the perturbation of the N cycle, and several review papers have highlighted the complexity of the formidable issues that are challenging environmental scientists (Vitousek, 1994; Galloway et al ., 1995; Vitousek et al ., 1997).     

Changes in the Distribution of 14C-Labelled Assimilates in Sugar-beet with Variation of Temperature

Plants were allowed to assimilate ¹⁴CO₂ for 30 min at 5, 15,25, and 35 °C. The changes in ¹⁴C content of a mature expandedleaf (Leaf 4), young apical leaves, and storage root, were sequentiallyfollowed over a subsequent period of 24 h in continuous light.In a second experiment plants were transferred after ¹⁴CO₂ assimilationto temperatures of 10, 18, 26, and 34 °C, and the partitionof ¹⁴C between the ethanol-soluble and ethanol-insoluble fractionsof the roots and leaves was followed over a period of 72 h. The specific activities of the apical leaves and of the storageroot increased to a maximum 2 h after labelling at 25 °C,4 h at 15 and 35 °C, and 6 h at 5 °C suggesting thatthe optimum temperature for translocation of photosynthate wasabout 25 °C. The ¹⁴C partition to ethanol-soluble and ethanol-insoluble fractionsof the roots and leaves was largely attained in. 9 h. Littlerepartition of ¹⁴C assimilate fractions occurred as a resultof temperature change or growth. Root ethanol-insoluble activity,however, did increase significantly over the 72-h period : possiblecauses of this slow incorporation and their relevance to themechanism of sugar storage are discussed.     

Abundance of Diurnal Raptors in Relation to Prairie Dog Colonies: Implications for Bird-Aircraft Strike Hazard

Abstract: Some diurnal raptors are frequently observed at prairie dog (Cynomys sp.) colonies. As a result, some military installations have conducted prairie dog control activities to reduce the bird-aircraft strike hazard (BASH) potential of low-flying aircraft. To evaluate the validity of this management strategy, we assessed raptor associations with prairie dog colonies at 2 short-grass prairie study areas: southern Lubbock County, Texas, USA, and Melrose Bombing and Gunnery Range in east-central New Mexico, USA. We quantified diurnal raptors (i.e., Falconiformes) at plots occupied (colony plots) and unoccupied (noncolony plots) by black-tailed prairie dogs (Cynomys ludovicianus) at both sites throughout 2002. We compared the number of individual birds of a given species at colony and noncolony plots within each study area by season. Ferruginous hawks (Buteo regalis) and northern harriers (Circus cyaneus) were more abundant at colony plots, whereas Swainson's hawks (B. swainsoni) and American kestrels (Falco sparverius) were more abundant at noncolony plots. Red-tailed hawk (B. jamaicensis) abundance did not differ between the 2 plot types. Our results suggest prairie dog control as a method of reducing BASH potential may be effective at some sites but may be ineffective or even increase the BASH potential at others. Thus, bird-avoidance models assessing the BASH potential should be conducted on a site-specific basis using information on relative and seasonal abundances of individual raptor species and the relative strike risks they pose to aircraft.