GEOG20009 Lecture 16: Lecture 16 Detailed Notes Landscapes & Diversity GEOG 20009

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LECTURE 16: KARST LANDSCAPE AND BIODIVERSITY
KARST LANDSCAPES
Karst: a landscape formed largely by dissolution of soluble rocks
3 preconditions for karst formation (karstification):
o Soluble rock limestone, dolomite, gypsum
o Secondary porosity bedding plane, fractures, faults
o Favourable climatic conditions availability of water
Speleology: subterranean cavity science caves, mapping
Biospeleology: studying the caves in regard to the biology
Cave Habitats
Subterranean habitats = all habitats below the Earth’s surface focus on
cave habitats
Cave characteristics:
o Lack of light
o High humidity
o Low and stable temperature
o Low food availability
Involve: terrestrial and water habitats, and a transitional zone
Cave Animals
Include occasional visitors of caves (salamanders)
Partially adapted cave animals (bats)
Fully adapted to caves
Schools of thought on why animals moved to caves
o Forced changes in ecological conditions on the surface (climate changes)
o Overabundance of species at the surface (competition)
Not all species migrate at the same time, and have different process of adaptation
Genetic and physical predispositions were prerequisite for successful adaptation to cave environment
Adaptation is a slow and lengthy process millions of years
o Involves regressive and progressive changes
Regressive changes: reduction of already existing characteristics loss of eyes, pigment,
diurnal rhythm
Progressive changes: development of new characteristics to accommodate loss of lost ones
longer extremities and development of sense, accumulation of fat, changes in brain
functioning
DINARIC KARST REGION
Hot spots of subterranean biodiversity in the world SE Europe Croatia and surrounding countries
Large number of endemic species lives in limited number of sites many found only in one location
Relicts and Endemics
Relicts: originated in certain geological period, no longer have relatives living fossils
o Genus with only one species
o Very restricted spatially found on very limited number of locations (endemic)
Dinaric Cave Clam
Only subterranean freshwater clam in the world
Marine animals, known only from a few localities in Dinaric Karst
Entered cave habitat via vertical migration into freshwater sediment at the sea margin left stranded when sea level
dropped
Olm Salamander
Endemic, only subterranean amphibian in Europe
Largest subterranean animal
Longest living amphibian
Predator top of the cave food chain
Bats
Pre-Process
Limestone is usually formed in shallow
and warm sea
Lithified calcium carbonate sediments
are mostly of biogenic origin
Rocks are uplifted by tectonic
processes above sea level
Then, karstification can start
Karstification
Limestone can dissolve in pure water
more soluble in natural waters which
contains weak acids
CO2 from atmosphere, and particularly
from soil catalyse this reaction
Results in underground cave systems
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Document Summary

Karst landscapes: karst: a landscape formed largely by dissolution of soluble rocks. Speleology: subterranean cavity science caves, mapping: biospeleology: studying the caves in regard to the biology. Su(cid:271)terranean ha(cid:271)itats = all ha(cid:271)itats (cid:271)elow the earth"s surfa(cid:272)e focus on cave habitats. Involve: terrestrial and water habitats, and a transitional zone. Schools of thought on why animals moved to caves. Limestone is usually formed in shallow and warm sea. Lithified calcium carbonate sediments are mostly of biogenic origin: rocks are uplifted by tectonic processes above sea level. Limestone can dissolve in pure water more soluble in natural waters which contains weak acids. Co2 from atmosphere, and particularly from soil catalyse this reaction: results in underground cave systems. Involves regressive and progressive changes: regressive changes: reduction of already existing characteristics loss of eyes, pigment, diurnal rhythm. Progressive changes: development of new characteristics to accommodate loss of lost ones longer extremities and development of sense, accumulation of fat, changes in brain functioning.

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