Effects of Experimental Interference with Stand Structure on Establishment of Seedlings in Callunetum

Miles, J.

doi:10.2307/2258948

Cited by 69 publications

(38 citation statements)

References 17 publications

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“…Despite this, many annual species germinated and established successfully -our figures equate to a minimum of 600 seedlings per square metre in 1986 in the heavily-grazed treatment. Even the largest gap size recorded here (12.8 m m diameter) is only one quarter of the smallest diameter of artificial gaps (50 mm) made in previous field work on seedling establishment (Miles 1974;Watt 1987a). This is in agreement with the micro-patterns of heavily grazed and lightly grazed patches produced by sheep grazing (Bakker et al 1983).…”

Section: Autumngrozedsupporting

confidence: 91%

The effects of sheep grazing on seedling establishment and survival in grassland

Watt

Gibson

1988

Vegetatio

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This paper examines the effects of sheep and insect grazing on the generation of natural gaps in turf and the establishment of seedlings therein. The site is on an old field on limestone. There were five sheep grazing treatments: ungrazed, and grazed briefly in spring, briefly in autumn, in autumn or in summer and autumn. The first three of these treatments also contained plots in which insecticide was applied regularly during the growing season. Pins of increasing size (1.6 m m -12.8 mm diameter) were lowered at grid intersections in permanent quadrats to record gap type and the occurrence of seedlings on seven dates over 15 months.Heavily-grazed plots had more bare ground in spring and more herb seedlings established in them. Seedlings of annual species of Bromus were able to establish in gaps (bare ground and litter) of smaller size than was required by herb seedlings (which had much smaller seeds). The use of an insecticide increased seedling establishment in October in ungrazed and in spring-grazed paddocks but decreased it in autumn-grazed paddocks. This may indicate the greater importance of insect herbivory in making gaps in the matted sward of autumngrazed plots. Seedlings which established in October 1986 and March 1987 were more likely to die than those establishing earlier in 1986. This may be because of winter-kill and especially vigorous spring vegetation growth respectively. Seedling mortality was not affected by gap size or grazing treatment (unless such effects operated before we detected the seedlings).

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Section: Autumngrozedsupporting

confidence: 91%

The effects of sheep grazing on seedling establishment and survival in grassland

Watt

Gibson

1988

Vegetatio

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“…The (Miles 1974;Fenner 1985), although under very dry conditions mortality in gaps may be higher than in closed turves (Ryser 1990). In species with no stratification requirement, germination may take place immediately after seed set, or, in species which germinate best at low temperatures, in winter.…”

Section: Introductionmentioning

confidence: 99%

Germination Strategies During Grassland Succession

Olff¹,

Pegtel²,

Groenendael³

et al. 1994

The Journal of Ecology

101

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. We analysed the germination of 91 herbaceous species in response to a temperature gradient, and to alternating temperatures and stratification (chilling). A principalcomponents analysis revealed that the species were distributed along two statistically independent axes, the first of which primary represented the optimal temperature for germination and the second the rate of germination. 2 These results were further related to data on species replacement during 25 years of succession in grassland after the cessation of fertilizer application but with continued hay making. Separate successional sequences were distinguished for the dry parts and the wet parts of the fields Changes in canopy structure were studied by counting gaps and mapping light at the soil surface. 3 Changes in species composition of species present at the different stages were related to the changes in the germination attributes during the succession towards nutrient-poor grassland. The productive grassland was characterized by rapidly germinating species and in the wetter parts, by those germinating at low temperatures. This might enable these species to escape from light competition by germinating in the autumn or winter, i.e. soon after seed set. The species from the less productive, more open stages germinated more slowly, and responded more clearly to stratification and alternating temperatures. It is therefore likely that germination of most seeds of these species is delayed until the following summer. 4 The importance of the observed interspecific differences in germination characteristics in relation to the observed changes in vegetation structure as an explanation for species replacement during succession is discussed. British Ecological Society

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“…Brokaw 1985;Goldberg & Werner 1983;Collins & Pickett 1987;Martinez-Ramos & Alvarez-Buylla 1986;Miles 1974;Wells & Haggar 1984). Furthermore, it has been suggested that different species have different requirements for the kind of gap they are able to colonize and that this provides one or more dimensions in which niche separation may take place (Denslow 1980;Grubb 1977;Silvertown & Wilkin 1983).…”

Section: Introductionmentioning

confidence: 99%

Gaps in the canopy: the missing dimension in vegetation dynamics

Silvertown

Smith

1988

Vegetatio

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Canopy gaps are important as entry points for new genotypes and new species into many types of vegetation, yet little is known about them in any type of vegetation but forests. Forest gaps are too large for manipulative experiments to be readily undertaken, and hitherto grassland gaps have been too small to be easily mapped. Preliminary results from mapping small (> 1 cm) grassland gaps with a new fibre-optic device suggest that experiments need to be performed at a smaller physical scale than has hitherto been achieved.

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Effects of Experimental Interference with Stand Structure on Establishment of Seedlings in Callunetum

Cited by 69 publications

References 17 publications

The effects of sheep grazing on seedling establishment and survival in grassland

The effects of sheep grazing on seedling establishment and survival in grassland

Germination Strategies During Grassland Succession

Gaps in the canopy: the missing dimension in vegetation dynamics

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