Bioaccumulation of lead by the lichen Acarospora smaragdula from smelter emissions

Accumulation of lead in the crustose lichen Acarospora smaragdula sensu lato is reported in the vicinity of an ore- processing plant where it is subjected to acidification and metal particulate fallout. A combination of light microscopy, X-ray element mapping, field emission scanning electron microscopy (FESEM) and other analytical techniques identifies Pb accumulation within specific fungal tissues derived from smelter particles (PM10s). No Pb was detected within the photobiont layer. Our studies suggest that Pb is highly mobile under the prevailing acidic conditions, and is fixed within the lichen cortex and melanized apothecia. Lead is also accumulated within the medulla and at the rock–lichen interface where it may precipitate as amorphous botryoidal encrustations on medullary hyphae and iron-rich particles. Modern FESEMs and microprobes enable analysis of minute quantities of material, and are important tools in understanding the fate of metals within lichens necessary to develop their use as predictive and sensitive bioindicators of aerial particulate contaminants. We suggest that crustose lichens, hitherto largely ignored in metal pollution studies, may be useful bioindicators of aerial particulate contaminants in polluted areas where macrolichens are absent.     

Products of Mitochondrial Protein Synthesis in Yeast

Analysis of membrane proteins of Saccharomyces cerevisiae mitochondria in cycloheximide-inhibited cells shows that they are encoded on mitochondrial DNA.     

Factors Related to Preferences for Trap-Neuter–Release Management of Feral Cats Among Illinois Homeowners

ABSTRACT Populations of feral domestic cats have increased throughout the United States, affecting wildlife and warranting attention from a variety of management agencies. This contentious issue requires a greater understanding of public attitudes and preferences for population control. We used data from a 2004 mail survey of Illinois, USA, homeowners’ attitudes towards wildlife and conservation to investigate support for the trap-neuter–release (TNR) of feral cats and to examine factors (demographic, experience, and wildlife values orientations) that may influence preference for TNR as a management option. Age, gender, and wildlife rights values orientations were significant predictors of preference for TNR, while negative experiences with feral cats were correlated with preferences for management options other than TNR. Investigations of public perceptions of feral cat management can help wildlife managers understand the growing public debate regarding feral cat management and provide appropriate input and educational materials regarding cat management and wildlife.     

Small Heat Shock Proteins Protect Electron Transport in Chloroplasts and Mitochondria During Stress

Evidence indicates that small heat-shock proteins (Hsps) areinvolved in stress tolerance, but the specific cell componentsor functions that small Hsps protect or repair are mostly unidentified.We recently showed that the chloroplast small Hsps of higherplants (1) are produced in response to many environmental stresses(e.g., heat, oxidative, and high-light stress); and (2) protect(but do not repair) photosynthetic electron transport in vitroduring stress, specifically by interacting with the oxygen-evolving-complexproteins of Photosystem II (PSII) within the thylakoid lumen.However, in vivo evidence of the importance of these Hsps tophotosynthetic stress tolerance is lacking. Here we report positiverelationships between chloroplast small Hsp production and PSIIthermotolerance in (1) a heattolerant genotype of Agrostis palustris(bentgrass) and a heat sensitive genotype which lacks one ormore chloroplast small Hsps produced by the tolerant genotype;(2) ecotypes of Chenopodium album (lambs quarters) from thenorthern vs. southern U.S. (New York vs. Georgia); and (3) nineLycopersicon (tomato) cultivars/species differing in heat tolerance.These in vivo results are consistent with our previous in vitroobservations and indicate that genetic variation in productionof the chloroplast small Hsp is an important determinant ofphotosynthetic and, thereby, whole-plant thermotolerance. Recently,we showed that the mitochondrial small Hsp of plants protectsrespiratory (specifically Complex I) electron transport in vitroduring heat stress, and here we present evidence for previouslyunidentified small Hsps in mitochondria of mammal (rat) cellswhich also protect Complex I during heat stress. These resultssuggest that the mitochondrial small Hsps, like the small chloroplastHsps, are general stress proteins that contribute significantlyto cell and organismal stress tolerance.     

A test for Allee effects in the self‐incompatible wasp‐pollinated milkweed Gomphocarpus physocarpus

It has been suggested that plants that are good colonizers will generally have either an ability to self‐fertilize or a generalist pollination system. This prediction is based on the idea that these reproductive traits should confer resistance to Allee effects in founder populations and was tested using Gomphocarpus physocarpus (Asclepiadoideae: Apocynaceae), a species native to South Africa that is invasive in other parts of the world. We found no significant relationships between the size of G. physocarpus populations and various measures of pollination success (pollen deposition, pollen removal and pollen transfer efficiency) and fruit set. A breeding system experiment showed that plants in a South African population are genetically self‐incompatible and thus obligate outcrossers. Outcrossing is further enhanced by mechanical reconfiguration of removed pollinaria before the pollinia can be deposited. Self‐pollination is reduced when such reconfiguration exceeds the average duration of pollinator visits to a plant. Observations suggest that a wide variety of wasp species in the genera Belonogaster and Polistes (Vespidae) are the primary pollinators. We conclude that efficient pollination of plants in small founding populations, resulting from their generalist wasp‐pollination system, contributes in part to the colonizing success of G. physocarpus. The presence of similar wasps in other parts of the world has evidently facilitated the expansion of the range of this milkweed.     

Diurnal Habitat Use by Lower Keys Marsh Rabbits

Abstract: We used radiotelemetry to locate daytime forms of endangered Lower Keys marsh rabbits (LKMRs; Sylvilagus palustris hefneri) throughout their range so we could determine habitat characteristics of diurnal cover. We typically found forms (n = 1,298) of 36 rabbits in brackish wetlands in patches of saltmarsh or buttonwoods. In freshwater wetlands, forms (n = 54) were located most often in patches of freshwater hardwoods embedded in or adjacent to freshwater marshes. Forms (n = 942) in brackish wetlands were characterized by thick groundcover (>75%), whereas those (n = 42) in freshwater wetlands had both thick groundcover and canopy vegetation. The mean minimum convex polygon around forms of 15 rabbits was 1.4 ha (SD = 1.7), with smaller ranges characterized by thick bunchgrasses or clump-forming sedges. To increase the amount of annual space usable by LKMRs, managers should provide more saltmarsh habitat interspersed with buttonwoods and enhance ground cover in existing habitat.     

Bird richness and composition along an agricultural gradient in New Guinea: The influence of land use,habitat heterogeneity and proximity to intact forest

Abstract We examined variation in bird species richness, abundance and guild composition along an agricultural gradient in New Guinea, and looked for any additive influence of habitat heterogeneity on these variables. The study was based on a grid of survey plots, six plots wide and 24 plots long with the long axis running from a settlement 2.4 km through active and abandoned agricultural plots towards a large area of forest. Each circular survey plot (25 m radius) was assigned to a broad habitat type, ten habitat measures taken, and birds counted for 1 h in each plot. Principal component analysis (PCA) habitat axis 1 described an axis of decreasing forest alteration (larger trees, greater tree densities, fuller canopy) that was positively correlated with distance from the settlement. Bird richness and abundance were highest at intermediate disturbance levels (plots with mid‐range axis 1 scores). Proportions of insectivores and frugivores increased with decreasing forest alteration, while proportions of nectarivores decreased. We calculated three measures of habitat heterogeneity by comparing each plot's PCA score to those of eight neighbouring plots (50–110 m away). These measures reflected how different the plot was to its neighbours, how variable the habitat was around the plot, and the degree to which the plot bordered less disturbed forest. We related these measures to plot bird variable scores independently, and to residuals following regressions of bird scores against PCA scores. Heterogeneity measures had no significant influence on abundance or richness measures, but there were greater proportions of frugivores in plots showing a given degree of habitat alteration if they bordered more pristine habitat. While we readily identified differences in bird communities along the agricultural gradient, the influences of habitat heterogeneity were not striking for birds at this fine scale.     

Freshwater stingrays from the Plio-Pleistocene of the Turkana Basin, Kenya and Ethiopia

The fossil freshwater stingray from the Turkana Basin of Kenya and Ethiopia is redescribed and reassigned to Dasyatis africana (Arambourg) on the basis of extensive new collections. The ray apparently evolved into an endemic freshwater species derived from a stock which entered the Turkana Basin from the Indian Ocean at about 1.9 Ma. At that time, the ancestral Omo River system flowed through a major lake and exited to the southeast. A fluvial corridor, termed the Turkana River, connected the Turkana Basin with the Indian Ocean. Once established in the basin, the rays flourished and persisted for over half a million years. Their extinction has been placed subsequent to 1.3 Ma, and likely reflects the changing environmental and tectonic conditions recorded in subsequent strata. The fluvial corridor which formed the route of migration into the Turkana Basin has important implications for modern African biogeography as well as that of the past. □ Turkana Basin, Kenya, Ethiopia, Pliocene, Pleistocene, Stingrays, Dasyatidae.     

Fungi on red raspberry from lesions associated with feeding wounds of cane midge (Resseliella theobaldi)

Two types of vascular lesion are described from the base of canes in plantations infested by raspberry cane midge ( Resseliella theobaldi ); (1) brown lobate lesions ('patches') confined to midge feeding areas, (2) brown lesions spreading proximally and distally from the point of infection ('stripes'). Either or both types of lesion may be presented in individual canes. Isolations from (1) produced principally Fusarium avenaceum ; isolations from tissues where (1) and (2) are contiguous gave Leptosphaeria coniothyrium and F. avenaceum ; isolations from (2) arising from old cane stub wounds in the absence of midge gave L. coniothyrium .
The important secondary role of fungi in the midge blight complex is confirmed, but the involvement of L. coniothyrium in the complex is unclear because it also infects stub wounds on midge-infested canes.     

Condition, growth and reproduction in female red lechwe (Kobus leche leche Gray 1850)

Information on condition, growth and reproduction was collected from a sample of 155 female lechwe in the Linyanti Swamp, northern Botswana. Condition varied significantly with age, reproductive state and season and indications were found of relationships between body mass and the attainment of puberty in young females and body mass and the fertility of adult females. There were also indications that the population was under nutritional stress because of high water levels and that this had caused reductions in the growth rate and fertility of young females. It is suggested that the sensitivity of young females to adverse environmental conditions could be exploited to optimize population monitoring for conservation purposes by using them as an indicator class, rather than monitoring the entire population. Because of relationships between condition, growth and reproduction, it is also suggested that long-term monitoring of condition should form part of any effort to understand population dynamics.