A Field-Portable Instrument for Mapping the Micro-Environment within Grass Canopies

Silvertown, Jonathan; Prince, Stephen D.; Smith, Ben

doi:10.2307/2389703

Cited by 15 publications

(6 citation statements)

References 10 publications

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“…Measurements of the ratio of light intensity in non-overlapping wavebands in the red and near infra-red (R/IR) made beneath the grassland canopy are directly correlated with leaf area index (Jordan 1969;Frankland & Poo 1980). A field-portable, microcomputer-controlled instrument (Silvertown et aL 1988) with a fibre-optic probe was used to record the R/IR ratio at 1 cm intervals in a grid pattern in grassland quadrats at the campus of the Open University in Milton Keynes, Buckinghamshire. Twelve quadrats 25 cm x 25 cm each in a ca 6 cm tall grassland of Loliumperenne were mapped in this fashion on 18 August 1987.…”

Section: Maps Of Grassland Gapsmentioning

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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Section: Maps Of Grassland Gapsmentioning

confidence: 99%

Gaps in the canopy: the missing dimension in vegetation dynamics

Silvertown

Smith

1988

Vegetatio

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“…Over the past decade or two, the fine‐scale horizontal dimension has become more appreciated as an important factor structuring plant communities. Its significance is primarily due to the sessile nature of plants (Pacala 1988), and concerns heterogeneity in resource levels both below ground (Caldwell & Pearcy 1994; Hutchings & de Kroon 1994; Stark 1994) and above ground (Silvertown et al 1989; Tang et al 1992; Tang & Washitani 1995). Horizontal heterogeneity of resources is a direct outcome of the important property of resources in terrestrial systems; namely, constraints on mobility in the horizontal direction.…”

Section: Introductionmentioning

confidence: 99%

Neighborhood effects and genetic structure in a clonal grass: The role of the spatial structure of the environment

Herben

Hara

Hadincová

et al. 2001

Plant Species Biology

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A dominant plant of temperate nutrient-poor grasslands, Festuca rubra, has been used as a model species to assess biotic effects of fine-scale environmental heterogeneity in the field and its genetic differentiation in response to this variation. Using experimental data, it is shown that this heterogeneity is partly due to interspecific variation in competitive abilities in the 'matrix' plants. Festuca rubra possesses remarkable intraspecific differentiation in its parameters of spatial spreading and competitive performance, and in their plasticity under cultured conditions. This morphological plastic response to the environment is weaker in the field. This indicates that in the field individuals use only a fraction of the full potential range of plasticity to respond to variation in competitive environments. A random amplified polymorphic DNA study has shown that populations of F. rubra consist of a high number of coexisting genets. The genet size distribution is strongly skewed, indicating high early stage mortality and lower larger genet mortality. There should be continuous seedling regeneration in order to maintain this genetic structure. The data presented here display major features that distinguish clonal expansion from vertical competition. These are: (i) absence of integration over the whole plant; (ii) potentially unlimited size; (iii) large and unpredictable environmental variation experienced by different parts of the genet; and (iv) absence of a size-determined competition outcome at the genet level, and thus higher potential for species-specific effects.

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“…*Present address and author to whom correspondence should be addressed: Division of Global Environmental Studies, National Institute for Environmental Studies, Tsukuba, Ibaraki, 305 Japan. ments at small scales from centimeters to meters within plant canopies is receiving increasing attention (Silvertown et al 1988;Tang et al 1990;Williams 1992). Silvertown et al (1988) showed a marked heterogeneity in R/FR ratios in a 160 cm 2 plot under a grass canopy and discussed its ecological implications.…”

Section: Introductionmentioning

confidence: 99%

“…ments at small scales from centimeters to meters within plant canopies is receiving increasing attention (Silvertown et al 1988;Tang et al 1990;Williams 1992). Silvertown et al (1988) showed a marked heterogeneity in R/FR ratios in a 160 cm 2 plot under a grass canopy and discussed its ecological implications. Within M. sinensis grass canopies, the spatial distribution of photon flux density (PFD) is highly heterogeneous (Tang et al 1989).…”

Section: Introductionmentioning

confidence: 99%

Characteristics of small‐scale heterogeneity in light availability within a Miscanthus sinensis canopy

Tang

Washitani

1995

Ecological Research

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To examine the small-scale variations in light and space availability, photon flux density (PFD) at 20 cm aboveground was measured at 2 cm intervals along each of four 160 cm horizontal transects under an overcast sky condition in a Miscanthus sinensis Anderss grass canopy. Two characteristics were identified for the variation patterns of PFD penetration along transects; the predominant variations of PFD penetration prevailed at the scales usually larger than 10 cm, and the point-to-point fluctuations occurred everywhere. Spatial autocorrelation coefficients of PFD penetration along transects were highly positive (> 0.5) over the lag distances from 2 to 6 cm, while those of the point-to-point fluctuations exhibited a random series. Spectrum analysis showed a higher spectrum density at the lower frequency, that is, at the higher periodicity, which indicated that the variation of PFD penetration was mainly due to the patchy distribution of grass canopy. PFD-available spans along the transects and contour maps were examined to evaluate the microsites fulfilling both PFD and space requirements in the growth of Quercus serrata Thunb. seedlings. More than 75 % of the spans with PFD penetration constantly exceeding 0.04 were shorter than 8 cm, which suggests that a large proportion of high PFD spots may not be used by Q. serrata seedlings in the grass canopy because of the limitation of availability in space. The spatial heterogeneity of PFD at small scales may be of great importance in the succession of M. sinensis grass communities.

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A Field-Portable Instrument for Mapping the Micro-Environment within Grass Canopies

Cited by 15 publications

References 10 publications

Gaps in the canopy: the missing dimension in vegetation dynamics

Gaps in the canopy: the missing dimension in vegetation dynamics

Neighborhood effects and genetic structure in a clonal grass: The role of the spatial structure of the environment

Characteristics of small‐scale heterogeneity in light availability within a Miscanthus sinensis canopy

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