Terrestrial home works Flashcards
Temple’s hypothesis
Calvaria major depended on dodo to scarify and disperse seed (co-evolution).
EXPERIMENT
- Temple force fed single seeds of Calvaria to 17 turkeys (similar size to Dodo)
- Seven of the 17 seeds crushed by Turkey gizzards
- Remaining 10 were either regurgitated or passed in faeces
- Three of these 10 seeds later germinated agter being planted in a nursery
- Temple’s conclusion: the present lack of regeneration of Calvaria refelcts its former dependance on seed scarification and disperal by the extinct Dodo
-Do you think his conclusion was justified?
Why/Why not?
- We don’t know much about turkey digestive physiology about extinct species, so their is a big assumption by Templer that it is similar to a Turkeys
- No conclusive evidence that Turkey and Dodo digestive track function the same
- No Control (fatal floor) 3/17 seats germinating, to interprid the significance of this a control is needed such as 17 seeds being planted naturally.
- When you do experimental treatment you must compare it with something
- More germination may have occured in a nursery, but nothing to compare.
Experiment
How could you test the effect of species 1 (circles) on species 2 (diamonds)?
1. Would removing circles in plot 1 accelerate or retard the arrival of diamonds.
(You have to have a control plot to determine the above)
If arrival of diamonds accelerated you can conclude there is inhibition occuring by the circles keeping plants out.
1. Which are Pioneers?
Definitely Ast - Maybe Ent
All possibly because they have high growth rates in gaps suggesting they grow best in open environment (more light)
(not Sch as no ditinct evidence suggesting it does grow better)
2. Which mechanism of succession describes the effect of the residual trees on most of the seven species?
Facilitators
CAV, EUG, MYR, TAB show clear signs of being facilitators as they have a higher survivability from seedlings than the ‘in gap’ species suggesting they grow better under the shade of other trees and have a better shade tolerance.
3 MAIN FOREST FORMATIONS
-Kauri-broadleaf forrest
3 MAIN FOREST FORMATIONS
Podocarp-broadleaf forests
3 MAIN FOREST FORMATIONS
Beech forest
Data set from Victoria, Australia with naturally regenerated stands of Eucalyptus species
(Probably post fire stand)
Stands thinned to diff densities plus a stand (controll) of 4000 left
Merchantable sizes are 32.5cm >
1. Which treatment has maximised the number of merchantable stems per hectare at age 64 years? Briefly explain your choice.
-Controll has most merachantable stands at 1308
2. Which treatment has maximised the volume of merchantable timber per ha? Show you working.
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2. Which treatment has maximised
Magnitudes of various water fluxes in an old-growth native forest at a site receiving 1500ml annual rainfall. Suggest corresponding flux figures under other land-uses at the same time.
PINUS RADIATA PLANTATION
Interception
Interception Old growth forest more patchy/gappy. Interception similar but it will be more uniform throughout as the trees are likely to be planted the same time. Plantation age willmake the biggest difference. Interception will be higher in older plantations as more wood to intercept. Wil be lower in young plantations as trees smaller and lower surface area of trunk.
Infiltration
Possibly less infiltration as there is less understorey in a forestry plantation. No fallen logs or debris.
Overland Flow
Faster as few obstructions preventing water run off compared to under story in a native forest.
Transpiration
Higher in pinus radiata plantation as they are very fast growing trees. Fast growth rate sustained by high photosynthetic rates which are linked to high transpiration rates.
GRAZED PASTURE
Interception
Low interception as much less cover due to grazing. Alot less leaf and stems to intercept also. It would increase if the pasture was left to grow naturally.
Infiltration
Low because because high compaction of the soil in grazed environments. Agriculture generally high compaction.
Overland Flow
High because of lower interception and lower infiltration.
Transpiration
In pastures it’s like farm land so you don’t have fast growing trees like you do in plantations and forests like a lot of the vegetation is grazed or sparse
And so the uptake or water and therefore transpiration is less
SUBURBAN ENVIRONMENT
Interception
Less than forests as more ground exposed.
Infiltration
Extremely low due to non permiable roads/pavements.
Overland Flow
Extreme overland flow. Huge problem as roads/footpaths are not permiable. Is reduced where draininage systems are well thought out.
Transpiration
Low, fewer trees so little photosynthetic activity.
Densitys of plant species in the browse layer inside (I) and outside (O) of 30 browsing mammal exclosure plots. At each location, the shaded bar is the larger of the two.
+, *, **, and *** indicate that the inside and outside values differ at
P < 0.10, 0.05, 0.01 and 0.001, respectively.
According to this evidence, identify plant species that are consistantly avoided by browsing mammals.
2 Possible Causes
Carying capacity overshot
Lack of preffered food/resources due to over population of ibex and because of the poor health of a bad diet reproduction rates drop and animals starve to death. To determine if this is the correct cause of death the carcus’s should be weighed and their general condition should be asseses to check their health (Autopsy)
Predation
Disease
Parasites
Why haven’t Eucalypts gone crazy in NZ like other invasives have?
1.Haven’t gone crazy because NZ climate is different to Euc’s native climate of Aus.
2.Eucalypts are strongly fire addapted. Regenerate best after a fire. Fires create big openings and Eucalypts are very light demanding (Pioneers). Perhaps there best chances of growth would be in open pastures in Northland (hot climate)
3. Eucalypts not as well dispersed as pines or a lack of suitable dispersers.
4. Not enough introduction attempts
5. Alpine climate to cold in South Island
