Some aspects of seed ecology of gorse

Ivens, G. W.

doi:10.30843/nzpp.1978.31.9336

Cited by 22 publications

(23 citation statements)

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“…When interpreting the data given below it is important to remember that Exapion destroys between 35% and 50% of seed production, and so seed bank density should be increased by a factor of c. 1·5. The distribution of seeds in the soil has been measured many times, and approximately 75% of all seeds are found in the litter and the top 5 cm ( Moss 1959;Ivens 1978;Zabkiewicz & Gaskin 1978). The size and behaviour of seed banks varies greatly.…”

Section:     mentioning

confidence: 99%

“…Chater (1931) recorded 44 seeds m -2 in close-turf plots, through which seeds could not penetrate, but 11 100 seeds m -2 in plots where there was a litter layer. Other instantaneous measures of seed bank density include 2070 seeds m -2 (Ivens 1978) and 133-20 742 seeds m -2 (mean = 5446; Zabkiewicz & Gaskin 1978). Partridge et al .…”

Section:     mentioning

confidence: 99%

“…Studies consistently show that gorse seedlings survive poorly in competition with pasture grasses ( Thompson 1974;Ivens 1979;Ivens & Mlowe 1980). Ivens (1978) found that 350 seedlings m -2 emerged over 16 months in plots initially cleared of vegetation, but mortality over that period was 41% and this increased as competing vegetation invaded the site. In undisturbed gorse plots, 170 seedlings m -2 were recorded and mortality was 70%.…”

Section:  mentioning

confidence: 99%

“…In undisturbed gorse plots, 170 seedlings m -2 were recorded and mortality was 70%. Seedlings surviving in the shade of bushes were etiolated, and were only 1% of the biomass of those in the open ( Ivens 1978). Partridge et al .…”

Section:  mentioning

confidence: 99%

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Large−scale disturbances, biological control and the dynamics of gorse populations

Rees

Hill

2001

Journal of Applied Ecology

327

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Summary 1.Simulation and analytical models were developed for gorse Ulex europaeus . The simulation model incorporated spatially local density-dependent competition, disturbance, asymmetric competition between seedlings and established plants, a seed bank, local seed dispersal, an age structured established plant population, and temporal variation in the probability of disturbance. The analytical models were simple approximations of the simulation. 2. The models extended our previously published model for Scotch broom Cytisus scoparius to include large-scale disturbances and possible management options, such as the use of fire, herbicides and oversowing with perennial grasses. Fire was assumed to influence established plant mortality, seed survival in the seed bank, and the probability of germination. 3. We reviewed published data on the demography of gorse in New Zealand, the current management techniques, and the ongoing biological control programme. 4. Over a wide range of biologically reasonable parameter values, the analytical models accurately predicted the outcome of the simulations. The analytical models worked well, providing gorse occupied a high proportion of the available sites and large-scale disturbances did not occur too frequently. 5. The potential impact of seed-feeding biological control agents on gorse abundance was assessed, using the models, for several environmental and management scenarios. In particular, we explored how large-scale disturbance, such as fire and herbicide application, influences the outcome of biological control. 6. The success of a biological control programme was found to depend critically on the frequency and intensity of disturbance, whether disturbed sites became suitable for recruitment, and the effects of disturbance on germination and seed mortality. 7. The models highlight the need to manage recruitment opportunities carefully in order to maximize the effect of biological control agents. The models also indicate that details of plant population biology can have a profound effect on the success of any management strategy.

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Section:     mentioning

confidence: 99%

Section:     mentioning

confidence: 99%

Section:  mentioning

confidence: 99%

Section:  mentioning

confidence: 99%

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Large−scale disturbances, biological control and the dynamics of gorse populations

Rees

Hill

2001

Journal of Applied Ecology

327

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“…The importance of gorse {Ulex europaeus L.) as a weed in New Zealand hill country pasture and the significance of seed in perpetuating gorse infestations have been di.scussed by Ivens & Mlowe (1980). Few seeds germinate in the shade of established gorse, but observations by Ivens (1978) showed that mechanical removal of a dense gorse cover was followed by a flush of germination as soon as moisture became available. The most likely explanation for the observed stimulation of germination was considered to be either the increased light intensity at ground level following removal of the canopy or associated changes in temperature conditions.…”

Section: Introduetionmentioning

confidence: 99%

The influence of temperature on germination of gorse (Ulex europaeus L.)

Ivens

1983

Weed Research

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Summary The germination of U. europaeus seed was investigated at temperatures between 4 and 40°C on a thermal gradient bar. At constant temperature the germination rate increased linearly with temperature from a minimum near 0°C to an optimum at 18°C and then decreased to a maximum at 26°C. At still higher temperatures seeds became imbibed but only germinated when transferred to cooler conditions. Above 35°C viability was lost. The rate of imbibition prior to germination increased with temperature over the whole range. Germination was not increased either by a light treatment or by potassium nitrate. Germination was not stimulated by a wide range of alternating temperature regimes and at mean temperatures below the optimum the germination rate could be adequately predicted from a formula based on performance at constant temperature. At higher temperatures the observed rates became progressively slower than predicted. Seeds from three different sources were tested, all showing similar relationships between germination rate and temperature but differing in the proportion of hard seed. The proportion was least with seed extracted from the soil, intermediate with a collection from the surface and greatest from pods. The findings are discussed in relation to germination in the field following clearing of gorse thicket.

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Analyzing the landscape characteristics promoting the establishment and spread of gorse (Ulex europaeus) along roadsides

et al. 2016

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The International Union for Conservation of Nature listed gorse (Ulex europaeus, Fabaceae), a heliophilous evergreen shrub, as one of the world's 100 worst invasive species. Over the years, multiple attempts have been made for controlling gorse, including biological methods, but they have not been fully successful. This study aims to investigate some aspects that still remain unexplored such as the relationship between anthropogenic disturbances with the spatial mechanisms of species spread. We aimed to fill this gap by analyzing the role of transportation network configurations and landscape context on gorse propagation. We surveyed the presence of gorse in southern Brazilian forest‐grassland mosaics by completing landscape‐level road transects coupled with remote sensing, to evaluate land use and landscape structure. A binary logistic regression model was performed to test the influence of independent variables (e.g., road orientation, type and category in addition to distance to the nearest habitat patch of forest, grassland and anthropogenic area) on gorse occurrence. Our results showed that the structure of road networks can facilitate the spread of heliophilous taxa like gorse. Specifically, local, paved, NWSE and NS‐oriented (which exhibited high light exposure) roads had the highest probability of finding gorse. This suggests that human transportation activity (traffic, road construction, and maintenance) constitutes a significant dispersal agent for the species. In addition, the landscape matrix context also played a significant role; gorse was most prevalent along roadsides close to urban or agricultural areas than to forests and grasslands. No area was completely free from disturbances, such as fire, livestock grazing, and silviculture, in these seminatural landscapes. We concluded that, disturbances affecting small‐scale processes, at roadside and adjacent habitat patches, were probably as important factors explaining gorse occurrence as the urban impact. Furthermore, the current work also emphasizes the need of understanding the complexity of interacting factors. Our work has important implications for ecosystem conservation and habitat management, and consequently should be considered a prior step in establishing new approaches for gorse control.

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Some aspects of seed ecology of gorse

Cited by 22 publications

References 0 publications

Large−scale disturbances, biological control and the dynamics of gorse populations

Large−scale disturbances, biological control and the dynamics of gorse populations

The influence of temperature on germination of gorse (Ulex europaeus L.)

Analyzing the landscape characteristics promoting the establishment and spread of gorse (Ulex europaeus) along roadsides

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