Climate clarification Albedo Definition: the extent to which an object reflects light from the sun Range of values: 0 to 1 Impact: high albedo, high reflectance less solar energy absorbed by object. Typical albedo Snow 0.8-0.9 Tundra shrubs 0.2 summer 0.6 snow covered
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Definition: the extent to which an object reflects light from the sun
Range of values: 0 to 1
Impact: high albedo, high reflectance
less solar energy absorbed by object
Tundra shrubs 0.2 summer
0.6 snow covered
Amazon forest 0.13
Amazon ranchland 0.18
Boreal forest 0.08
Boreal grass 0.2
Warming will melt sea ice and promote growth of shrubs in the arctic
Puddles and shrubs have lower albedo (reflectance) than ice and tundra
Puddles and shrubs will warm up rather than reflect solar energy
Warm puddles and shrubs will increase ice melt and promote further shrubification
+- indicates effect of forest
+- indicates effect of forest
A Case study:
Lake Victoria’s Nile perch fishery and cichlid biodiversity
1858 “discovered” by John Speke
- sparsely populated region
- subsistence fishery (small native species)
1902 – colonial government links lake to Mombasa
1930 – Europeans had deforested watershed
- planted tea coffee sugar tobacco cotton
- population had exploded
- urban centres provided market for fish
1950 – native tilapia commercially extinct
1951 - English introduce non-native tilapia
1955 – English introduce Nile Perch
1955 – introduced to Lake Victoria
1969-70 Haplochromines 83% biomass
Nile perch 0.05%
1980’s Nile Perch 80% biomass
Massive loss diversity
400+ 200 species
– the next 30 years
Decline has continued
Intensive fishing led to a resurgence of native species
Haplochromine cichlids, particularly pelagic species recovered
Three areas acted as refugia
- Wetlands and rocky habitats
- Hypoxic areas
- Satellite lakes
But current environment is very different
New fauna will differ in richness,
composition and ecosystem function
Award winning documentary by
Hubert Sauper is a tale about
Lake Victoria, humans in the north and south, globalization,
corporate corruptness, and fish.
The following are excerpts
from the film.
If goal is to conserve the remaining cichlid diversity what should conservation biologists do?
The Lake Victoria Fisheries Research project has organised fisheries managers to work on quantifying the fisheries stocks of Lake Victoria and has also managed to bring together scientists from the 3 countries to exchange views and identify gaps in research and recommend how to deal with those gaps.
Planning for the lake’s future (economically and biologically) may proceed with a two-pronged approach:
Lake Victoria Fisheries Organization (LVFO) comprises stakeholders whose objective is to
“protect and restore the lake”.
Where is the political power?
Whose interests are being protected?
Given the population pressure and the industry/political pressure
what would YOUR conservation strategy be?
Possible avenues for biodiversity conservation stakeholders whose objective is to
Conservation of habitat and biodiversity will only succeed if water quality is improved –
nutrient levels and toxic contamination should be controlled
Stock management strategies linked to rational regulation of fishing effort are needed
Representative habitats in the lake should be conserved with focus on high diversity areas, refugia, satellite lakes and shoreline wetlands
Development of an integrated basin wide plan
- international cooperation is necessary to regulate nutrient influx and fishing pressure