Association between competition and facilitation processes and vegetation spatial patterns in alpha steppes

In semiarid ecosystems, the self-organized spatial patterns of plants associated with catastrophic shifts can emerge from a variety of processes. In this study, on moderate slopes where Stipa tenacissima cover was high, the self-organization of some of the typical species of semiarid Mediterranean matorral ( Phlomis purpurea , Sideritis oxteosylla, Helianthemum almeriense , and Brachypodium retusum ) was negatively correlated with Stipa cover. The extent of Stipa cover did not affect desert pioneer species, such as Artemisia herba-alba , Fagonia cretica , and Launaea lanifera . On pronounced slopes, the self-organizing structure of brushwood vegetation did not vary predictably with the amount of Stipa cover. We examined the competition/facilitation processes associated with self-organizing patterns in the dwarf shrub ( Phl. purpurea ) and the half shrub ( H. almeriense ). The developmental stability of H. almeriense was positively correlated with Stipa cover, which was expected because they are associated species in this seral thyme brushwood community. Indeed, facilitation processes were manifested by the developmental stability increases under the Stipa canopy, particularly on high slope areas, where Stipa is less competitive. In Phl. purpurea , negative feedback processes from competition with Stipa were manifested where Stipa cover was high and on low slopes (developmental instability increased). In general, competition with Stipa on low slopes tended to decrease plant self-organization.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 103–113.     

Self‐stigma and the “why try” effect: impact on life goals and evidence‐based practices

Many individuals with mental illnesses are troubled by self-stigma and the subsequent processes that accompany this stigma: low self-esteem and self-efficacy. “Why try” is the overarching phenomenon of interest here, encompassing self-stigma, mediating processes, and their effect on goal-related behavior. In this paper, the literature that explains “why try” is reviewed, with special focus on social psychological models. Self-stigma comprises three steps: awareness of the stereotype, agreement with it, and applying it to one’s self. As a result of these processes, people suffer reduced self-esteem and self-efficacy. People are dissuaded from pursuing the kind of opportunities that are fundamental to achieving life goals because of diminished self-esteem and self-efficacy. People may also avoid accessing and using evidence-based practices that help achieve these goals. The effects of self-stigma and the “why try” effect can be diminished by services that promote consumer empowerment.     

First molecular identification of the vertebrate hosts of Culicoides imicola in Europe and a review of its blood‐feeding patterns worldwide: implications for the transmission of bluetongue disease and African horse sickness

Culicoides (Diptera: Ceratopogonidae) are vectors of pathogens that affect wildlife, livestock and, occasionally, humans. Culicoides imicola (Kieffer, 1913) is considered to be the main vector of the pathogens that cause bluetongue disease (BT) and African horse sickness (AHS) in southern Europe. The study of blood‐feeding patterns in Culicoides is an essential step towards understanding the epidemiology of these pathogens. Molecular tools that increase the accuracy and sensitivity of traditional methods have been developed to identify the hosts of potential insect vectors. However, to the present group's knowledge, molecular studies that identify the hosts of C. imicola in Europe are lacking. The present study genetically characterizes the barcoding region of C. imicola trapped on farms in southern Spain and identifies its vertebrate hosts in the area. The report also reviews available information on the blood‐feeding patterns of C. imicola worldwide. Culicoides imicola from Spain feed on blood of six mammals that include species known to be hosts of the BT and AHS viruses. This study provides evidence of the importance of livestock as sources of bloodmeals for C. imicola and the relevance of this species in the transmission of BT and AHS viruses in Europe.     

Comparison of two sampling methods for domestic populations of Triatoma infestans in north-west Argentina

Abstract. In mud-and-thatch houses of Santiago del Estero Province, northwest Argentina, where no insecticides had been sprayed officially to control domestic infestations of the Chagas disease vector Triatoma infestans (Klug) (Hemiptera: Reduviidae), two knockdown (KD) insecticidal collection procedures were compared with the standard flush-out (FO) method for sampling T. infestans. Bugs were collected by FO using 0.2% tetramethrin in bedrooms of (1) 41 houses of Amama village employing 1 man-hour of capture effort per house, and (2) 19 houses of Trinidad and Mercedes villages employing 4 man-hours/house. From the same houses, 2-5 days after the manual FO collection, bugs were collected by KD indoor-spraying of deltamethrin 25mga.i./m² in Amama, or burning of one γ-HCH (=γ-BHC) fumigant tablet 3.1g of γ-isomer) per bedroom in Trinidad and Mercedes. The majority of infestations were detected by both methods, the proportion of positive houses being 81% at Amama and 95% at the other villages. Although the FO method was more sensitive, at least because it was applied first, the KD method detected infestations in 25% of houses where bugs were not found by FO. Bug densities estimated by FO or by subsequent KD in each house were significantly correlated: r = 0.795 for deltamethrin; r= 0.882 for y-HCH. Compared with FO collections of T.infestans large stages, i.e. adults plus fourth and fifth instar nymphs, the KD catch averaged 0.88x with deltamethrin and 0.57× with γ-HCH, regardless of the apparent population density of bugs per house. However, the KD method has practical advantages of speed and standardization.     

Spring phenology in boreal Eurasia over a nearly century time scale

It has been widely reported that tree leaves have tended to appear earlier in many regions of the northern hemisphere in the last few decades, reflecting climate warming. Satellite observations revealed an 8-day advance in leaf appearance date between 1982 and 1991 in northern latitudes. In situ observations show that leaf appearance dates in Europe have advanced by an average of 6.3 days from 1959 to 1996. Modelling of leaf appearance on the basis of temperature also shows a marked advance in temperate and boreal regions from 1955 to 2002. However, before 1955, reported studies of phenological variations are restricted to local scale. Modelling, ground observations and satellite observations are here combined to analyse phenological variations in Eurasian taiga over nearly a century. The trend observed by remote sensing consists mainly in a shift at the end of the 1980s, reflecting a shift in winter and spring temperature. In western boreal Eurasia, a trend to earlier leaf appearance is evident since the mid-1930s, although it is discontinuous. In contrast, the strong advance in leaf appearance detected over Central Siberia using satellite data in 1982–1991 is strengthened by late springs in 1983–1984; moreover, in this region the green-up timing has displayed successive trends with opposite signs since 1920. Thus, such strong trend is not unusual if considered locally. However, the recent advance is unique in simultaneously affecting most of the Eurasian taiga, the leaf appearance dates after 1990 being the earliest in nearly a century in most of the area.     

SHELL GROWTH OF THE COCKLE CERASTODERMA EDULE IN THE MUNDACA ESTUARY (NORTH SPAIN)

In order to establish a growth curve for the life-span, agedetermination based on shell-ring analysis was undertaken ina population of the cockle Cerastoderma edule located in theMundaca Estuary (Basque Country, North Spain). Mean values ofheight at shell rings showed non-significant differences betweengenerations, meaning absence of interannual variations in growthrate. Frequent sampling and shell measurements over a 20 monthperiod allowed determination of the seasonal pattern of shellgrowth, which was subsequently incorporated into a growth curve. An attempt has been made to relate growth rates to latitudefor different populations of C. edule, using both data fromthe literature and the results of this study. The highly significantcorrelation found (P<0.01) confims the existence of a latitudinaltrend, with growth rates increasing southwards. Low rates ofgrowth recorded for cockles from Mundaca, by camparison withpupulations of similar latitude, are interpreted in terms ofnutritional restrictions associated with both the high tidalposition of the population and poor productivity conditionswithin this particular estuary. (Received 24 March 1989; accepted 20 June 1989)