Grasslands Flashcards
What is a heliophile?
Sun loving species
What is the elm decline?
Occurred at boundary between sub zones VIIa/b, Atlantic/Sub Boreal boundary
establishment of neolithic farming in Britain, decline due to disease, selective cropping and pollarding
What is the landnam clearance?
Similar time to elm decline, temporary forest clearance in Denmark, shown in pollen count as a decree of trees and an increase in grass and herbs
Cleared for pastures
5 peaks of plantago pollen, suggesting 5 clearances
What are the neolithic clearances?
More extensive and permanent deforestation, associated with well populated areas
What are the Bronze Age clearances?
Continuation of landnam clearances with increased intensity
What are the iron age clearances?
climactic deforestation, marked an increase in precipitation, continuation of Bronze Age clearances
How are grassland managed?
By grazing or mowing, which is partial defoliation
What is adpressed growth?
Close to the ground or stem, e.g. negatively phototrophic rosettes, not easily grazed
What are the adaptations of grassland plants?
Intercalary meristem, adpressed growth, low palatability and ephemeral life history
What is an example of a plant with adpressed growth?
Plantago lanceolata
How are plants adapted for low palatability?
Spines, woody tissues, distastefulness and chemical toxins
What are ephemerals?
Grow rapidly in periods of limited grazing, short life cycle, exploit patches of bare soil
What is a calcifuge species?
Species growing on acidic soils e.g. Nordus stricta
What is a calcicole species?
Species growing in calcareous soils e.g. Scabiosa columbaria
What is an example of a species that can grow in a range of soil ph?
Festuca ovina
What is the major impact of pH on plant distribution?
the influence on availability of other ions
What type of grassland occurs in Peak District?
limestone grassland, very species rich
What is the characteristic soil of limestone grasslands?
Rendzina
What are rendzina soils?
Immature, high pH and low fertility, thin due to purity of the bedrock , little residue on dissolution
What is a toposequence?
A sequence of soils in which distinctive soil characteristics are related to topographic situation
What is a podzol?
An infertile, acidic soil
What soils and species would you expect on a plateau?
Podsol pH<5, Low fertility,
Deschampsia flexuosa, Calluna vulgaris, Festuca ovina
What soils and species would you expect on a slope?
Rendzina, pH>7, low fertility,
Festuca ovina
What soils and species would you expect on a valley bottom?
Brown earth/alluvium
pH 5.5-7.5, high fertility
What does Grime’s classic “hump-backed curve” show?
between crop-mass 300 - 900 g m-2, =
corridor of high potential species richness
Calcareous (limestone or chalk) grasslands have intermediately low nutrient status = high alpha diversity
How is pH a driver of species richness?
helps account for variation in richness within the crop- mass corridor of 300 - 900 g m-2
Low pH soils invariably species poor,
What is the reservoir effect?
fewer species adapted to grow in acid soils that calcareous soils
