The movements of small mammals within the environmental mosaic of a railway junction

This study investigated small mammal movements within and between semi isolated habitat islands. The results are relevant to urban small mammal species in general and their movements in relation to man-made barriers in particular. The study site was a railway junction consisting of railway tracks of different widths, dissecting an area of relict grassland in an otherwise urban environment.For two years the small mammals in this area were trapped, marked and recaptured. They were also tracked using dyed bait markers and a grid of dropping boards from which were recovered faeces containing remains of the dyed bait. The ability of the small mammals present (Apodemus sylvaticus, Clethrionomys glareolus and Microtus agrestis) to cross the railway lines was correlated with weight and sex; and also related to the width of the railway track and the vegetation on either side.Conclusions were reached concerning the distribution and behavioural ecology of the three species within the study area, particularly in relation to the animals' capabilities for movement within heterogeneous habitats.The biogeography of small islands such as these was considered, with reference to the effects of size and isolation on mammal movements. The effect of population density on such movements and possible local migratory effects were also investigated. The implications for conservation were discussed and it was shown that information from fieldwork such as this can aid biogeographical analysis in reserve design (for conservation of urban mammal populations) and aid in urban planning. <p

Does Green-Person-Organization Fit Predict Intrinsic Need Satisfaction and Workplace Engagement?

The current study assessed whether high green-person-organization fit (GPO; the extent to which an organization’s commitment to pro-environmental outcomes is congruent with its employees’ environmental values) predicts employees’ intrinsic need satisfaction and engagement in the workplace. The sample consisted of 818 full-time Australian workers, which is sourced from an online panel. Consistent with the GPO model, pro-environmental work climate was a more potent predictor of intrinsic need satisfaction and engagement for employees with strong ecocentric values than those with weak ecocentric values. Mediation analyses revealed that the effect of work climate on employee engagement was fully mediated by intrinsic need satisfaction, and this effect was strongest when GPO fit was high. Overall, our findings suggest that organizations with pro-environmental work climates that match their employees’ values have more satisfied and committed workforces

The response of Plantago major ssp pleiosperma to elevated CO2 is modulated by the formation of secondary shoots

The effect of elevated CO2 on the relative growth rate (RGR) of Plantago major ssp. pleiosperma was studied during the vegetative stage, in relation to plant development, by growing plants at 350 mu l l(-1) or at 700 mu l l(-1) CO2 in non-limiting nutrient solution with nitrate. To minimize interference by the accumulation of non-structural carbohydrates in the interpretation of results, RGR was expressed on a f. wt basis (RGR(FW)), as were all plant weight ratios. Stimulation of the RGR(FW) Of the whole plant by elevated CO2 was transient, and did not last longer than 8 d. At the same time a transient increase in root weight ratio (RWR) was observed. In order to investigate whether the transient effect of elevated CO2 on RGR(FW) was size-dependent, the data were plotted versus total f. wt (log(e) transformed). The transient period of stimulation of RGR(FW) and of RWR by elevated CO2 was still found, but in both CO2 treatments RGR(FW) decreased after a certain plant size had been reached. This size coincided with the stage at which secondary shoots started to develop, and was reached earlier in plants grown at elevated CO2. The RGR of these secondary shoots (RGR(see)) was Still increased when the period of whole plant stimulation of RGR(FW) had ended, indicating that the development of these new sinks took priority over a continuation of the stimulation of RWR. It is hypothesized that in this Plantago subspecies the response of the RGR(FW) of the whole plants to elevated CO2 is modulated by the formation of secondary shoots. Apparently, partitioning of the extra soluble carbohydrates at elevated CO2 to this tissue takes precedence over partitioning to the roots. resulting in a cessation of stimulation of plant RGR(FW) by elevated CO2.info:eu-repo/semantics/publishedVersio

Cluster illumination differentially affects growth of fruits along their ontogeny in highbush blueberry (Vaccinium corymbosum L.).

Shading highbush blueberry plants generally leads to a delayed fruit development. Experiments have been performed to study the effects of light on fruit growth independently from the rest of the canopy. Clusters were shaded during different fruit growth periods. The equatorial diameter of the fruits as a function of days after full bloom followed a double-sigmoidal growth pattern, being fitted using a Gompertz II nonlinear mixed model, and absolute growth rates were obtained from each fitted model. Both whole-cycle shaded and second-stage shaded fruits showed a delayed peak in absolute growth curves with respect to both first-stage shaded and whole-cycle unshaded controls. Our results suggest that deficiency of light during the last stage of highbush blueberry fruits may lead to a substantial delay (of about 10–16 days) in harvest as compared with well-illuminated fruits. In order to estimate the contribution of intrinsic fruit photosynthesis to its own growth at different stages, clusters were subjected to girdling on their peduncles at different times. Girdling just before the second-stage resulted in fruits gaining between 35 and 40% of dry weight in comparison with the controls. This suggests that fruit photosynthesis may play a relevant role in fruit growth during the second sigmoidal stage, which in turn may contribute to explain the delayed growth observed in shaded fruits

Some effects of supplemental carbon dioxide on the physiology of plant growth and development

This research was concerned with some physiological effects of supra-normal CO₂ concentrations on cucumber, tomato and Japanese Morning Glory (Pharbitis nil), and with measurement of CO₂ levels in a commercial greenhouse. Measurements of CO₂ concentrations in a cucumber greenhouse showed that, in the early stages of crop development, early morning CO₂ levels reached 0.18% as a result of straw decomposition in the plant beds. Later in crop development, daytime levels were much lower and required gas combustion to restore high concentrations. Stomatal resistances in cucumber leaves were relatively insensitive to high greenhouse concentrations. Variation in stomatal resistance through the crop canopy was, however, detected. Generally, the two most recently developed leaves showed higher resistances than those of a slightly greater physiological age. Differences in leaf irradiance could not fully explain this effect, which may be related to the stage of leaf development. Subsequent experiments on greenhouse tomato crops showed that CO₂-enriched (0.09% CO₂) plants flowered earlier and produced 30% more fruit than those grown in normal air. Photosynthetic rates were inherently higher in apical and basal leaves developed under CO₂enrichment at irradiances above 50 m⁻²s⁻¹ .Behavioral indicies of photosynthetic efficiency indicated an enhanced capacity to utilize CO₂ in enriched plants. Measurements of CO₂ exchange in leaves of plants grown in chambers at 3 CO₂ concentrations (0.03, 0.1 and 0.5%) confirmed the enhancement of inherent photosynthetic rates in young leaves of 0.1% grown plants. Reduced rates of photorespiration, total O₂ inhibition of photosynthesis, glycolate oxidase (GaO) activity, and an increased rate of ribulose-biphosphate-carboxylase (RuBP-case) activity, contributed to this enhancement. Maximum photosynthetic rates in young leaves developed at 0.5% CO₂ were similar to those developed in 0.03% CO₂. Growth rates of the 0.1% CO₂-grown plants were higher than the similar rates of plants from the 0.03 and 0.5% regimes. Apparently maximum benefit from CO₂ enrichment is achieved by maintaining atmospheric CO₂ concentrations close to 0.1%. At a later stage of development, however, GaO and RuBP-case activities were similar in the 0.03 and 0.1% CO₂-grown plants and photosynthetic rates did not differ between growth regimes. Observations on the effects of 0.03, 0.1, 1.0 and 5.0% CO₂ on development in the Short-Day Plant Pharbitis nil revealed that 1.0 and 5.0% CO₂ modified normal flowering. These concentrations induced a weak flowering response in Long-Days and Short-Days and promoted stem elongation and leaf production under both photoperiods. These modifications were apparently unrelated to patterns of CO₂ exchange which showed a relatively small increase above 0.5% CO₂. These results are discussed in relation to possible mechanisms for the effects of supra-normal CO₂ concentrations on development. The diversity of physiological effects mediated by CO₂, and their relationship to one another are discussed.Land and Food Systems, Faculty ofGraduat

Molecular detection of Angiostrongylus vasorum in gastropods in Surrey, UK

Surrey, a county in southern England, is a hot spot for angiostrongylosis in domestic dogs but there have been no investigations into the intermediate hosts of Angiostrongylus vasorum in this area. This study aimed to determine the prevalence of A. vasorum in gastropods in Guildford, the most populous town in Surrey, and to ascertain which gastropod species can act as intermediate hosts for A. vasorum. Gastropods (n=97) were sampled in six locations, representing urban, suburban and rural environments and identified to species based on morphological features. A PCR assay was used to detect A. vasorum DNA in gastropod tissue and the species of infected specimens was confirmed by sequencing of mitochondrial genes. 4.1% (4/97) of sampled gastropods and 9.1% (4/44) of sampled slugs were A. vasorum positive. Infected gastropod species were Arion rufus (n=3) and Deroceras invadens (n=1), the first description of the latter species as a potential intermediate host for A. vasorum. Two infected slugs were sampled in urban environments and two in suburban environments. The results demonstrate that there is a risk of transmission of A. vasorum to domestic dogs from the gastropod population in urban and suburban areas of Guildford

The Physiological Ecology of Dicranum fuscescens Turn in the Subarctic

Experiments designed to ellucidate the physiology of the subarctic moss Dicranum fuscescens in relation to its environment were conducted at Schefferville, Quebec (latitude 55°N) throughout the summer of 1974. Two study sites were chosen, a lowland lichen woodland and highland semi-tundra area. Laboratory measurements of net CO2 exchange in relation to light intensity and temperature indicated an acclimation to warmer conditions in the mid-season. Subsequent experiments on field collected samples exposed to different growth chamber regimes confirmed the seasonal temperature acclimation response. Light saturation points for photosynthesis showed an increase through the mid-season and subsequently declined. Absolute rates of net photosynthesis were higher in the semi-tundra plants throughout July and August. Maximum diurnal rates of net photosynthesis in fully moist samples were between 8 and 9 mg C02 · g dry weight -1 · day -1. […]Des expériences destiné àexpliquer la physiologie de la mousse subarctique Dicranum fuscescens en relation avec son environment, ont été faites a Schefferville, Quebec (55° latitude N) pendant l'été 1974. Deux stations d'étude ont été choises: une plaine boisée ou on note la présence de lichen et une région de hautes terres et de semi-toundra. Des mesines photosynthèse nette en relation avec ‘intensité lumineuse et la température ont été prises en laboratoire. Elles montrent que les mousses peuvent s'adapter à des conditions plus chaudes au milieu de la saison. Des expériences subséquentes faites sur des spécimens récoltés sur la terrain, soumis à differentes conditions de croissances controlées, confirment l'adaptation des mousses aux différents températures saisonnières. Les points de saturation de photosynthèse en fonction de l'intensité lumineuse montrent une augmentation en mis saison suive d'une diminution. Les taux absolus de photosynthèse nette étaient plus hauts pour les plantes de la région semi-toundra pendant Juillet et Aout. Les taux maximums diurne de photosynthèse pour les spécimens mouilles étaient entre 8 et 9 CO · poids sec -1· jour. […

Prohexadione-calcium modifies growth and increases photosynthesis in strawberry nursery plants

Prohexadione-calcium (ProCa) at an active ingredient concentration of 62.5 mg L-1 was applied as a foliar spray to Camarosa and Sweet Charlie strawberry (Fragaria x ananassa Duchesne) plants in growth chambers to assess its effects on dry weight allocation and growth over 42 d. The height, leaf number, leaf area, and specific leaf area (SLA) of daughter plants and the total dry weights of their leaves, stems and roots were all affected by ProCa treatments. Treated plants weighed less than untreated plants for the first 28 d after treatment, but by 42 d, all plants were similar in total weight regardless of treatment. ProCa-treated plants consistently allocated more dry weight to roots, and proportionally less to shoots, and were reduced in height, leaf area and SLA. ProCa increased net photosynthesis in plants grown in growth chambers and in the field. Plants grown in the field responded to ProCa earlier, and their photosynthetic rates were higher (i.e., 23-34% higher in daughters and 34-41% higher in mothers) than those grown in growth chambers