Lecture 18-Biogeography of Coasts Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is biogeography?

A

• Science documenting geographic patterns of biodiversity -has largely focused on species diversity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the three historic phases of biogeography?

A
  1. descriptive (ecological) 2. narrative 3. analytical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the definition of a biogeographic province?

A

-coastal region characterised by a relatively distinct and homogenous flora and fauna, with only a small percentage of species common to adjacent regions, and usually differing in temperatures from adjacent provinces by more than 5°C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the O’Hara and Poole study (example of a biogeographic study).

A

•Patterns in species composition, species richness and endemism •347 echinoderm spp. -392 decapod spp. -biogegraphy study of echinoderms and decapods in southern australia -looked at distribution in these two groups -divided the coast into cells and recorded if the organism was there or not(•57x 1° lat/long cells along coast) -shows you have geographic structure 5 biogeographic regions present in the southern coast -strong evidence for biogeographic regions along coast -Fauna related to sea surface temperature, latitude, longitude, break-up of Gondwana

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What was the distribution of Meridiastra calcar and Uniophora granifera in the O’Hara and Poole study and what does it show?

A

• Meridiastra calcar(doesn’t give you much info for biogeography as it is widely distributed) – Albany, WA, to Qld & around Tas. –␣Rockpools, sheltered reefs – Mid-intertidal to 10 m •Uniophora granifera – Spencer Gulf, SA to Solitary Is, NSW, & around Tas. – Sheltered reef, silt, seagrass – 0 to 30 m(this one gives you information as it is not widely distributed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the patterns driving biogeographic distrivution? (4)

A
  1. Plate tectonics 2. Ocean currents & sea temperature 3. Habitat availability 4.Ability of species to disperse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How did the breakup of Gondwana affect biogeography? (1. Plate tectonics)

A
  • along south australia= get different species than east australia as the organisms could interact only for 30MY
  • By 30 Ma, Australia completely separated from Antarctica
  • huge timescale
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is unusual in Australia’s geography of the coast?

A
  • huge amount of south-facing coastline unlike south africa and south america
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the unusual current around Australia? (2. ocean currents and sea temperature)

A

•Unusual to have warm current flowing polewards on east side of ocean basin in southern hemisphere

  • red= coastal Loewen current -tropical water goes around the corner to the south coast
  • unusual
  • so thanks to that trpical organisms get transferred that way
  • go quite far south
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the sea temperature gradient in the world? (2. ocean currents and sea temperature)

A

• Gradient from tropics to poles •Also varies spatially over smaller scales • Has fluctuated through geological time spatial variation over small scales= vary in temp -around victoria= upwelling so cold -latitude biodiversity gradient= more species richness of organisms= but not with algae!!! -in colder water= more diversity of algae than in warmer water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does species richness change with temperature? (2. ocean currents and sea temperature)

A

In general, spp. richness increases with temp. – exceptions include benthic macroalgae • diversity & endemism v. high in southern Aust. -macroalgae are more diverse in cold waters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How long is the Australian coastline and how much of it is sandy beach and rocky shore? (3. Habitat availability)

A
  • coastline approx. 36,000 km – approx. 50% sandy beaches – approx. 40% rocky shores -the remaining 10% are various (estuaries etc.) –more contemporary timescale -determines the biogeography, eg. barnacles= need rocks so won’t occur in sand -mangroves= cannot grow in rocky shore, must have estuaries as less exposed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What determines a species’ ability to disperse? (4. Ability of species to disperse)

A

=Many benthic species have planktonic stage in life history – gametes –spores or larvae =Potential for currents to aid dispersal -so presence of currents and if they have larvae and what type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the two types of larvae?

A

-Lecithotrophic larvae -Planktotrophic larvae (Not always larvae/spores => e.g. seaweeds= disperse via adult thalli)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the characteristics of Lecithotrophic larvae?

A

– non-feeding – [lecitho = egg yolk, trophic = feeding on] – rely on energy reserves – relatively large & few in number –short time in plankton (mins to hrs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the characteristics of Planktotrophic larvae?

A

– [plankto ~ plankton] –obtain own food –relatively small & numerous –longer time in plankton

17
Q

How does time come into dispersal?

A

•More time in water = more potential for dispersal –Quick-settling spores of Postelsia released in spray of rising tide (must settle in matter of hours) – King George whiting larvae drift for 3 - 5 months, the adults swim out and lay eggs, then larvae drift with the current back to Port Philip Bay

18
Q

What is the dispersal of King George whiting like?

A

–cycles in catches match cycles in westerly wind strength,as more larvae transported then with the current –good settlement in PPB corresponds to warmer SST west of Cape Otway

19
Q

Are the planktonic stages completely at mercy of currents?

A

-no -like in the example of Western rock lobster

20
Q

What is the dispersal mechanism of the Western rock lobster?

A

– phyllosoma larvae [phyllo = leaf, soma = body] – migrate vertically to catch offshore currents –spend 9–11 months 400+ km in open ocean (Indian Ocean) –daily vertical migration 0–60 m –late-stage larvae between 60–140 m depth during day to catch east-flowing current -once they grow large enough drop to the current and go towards the coast

21
Q

What are the cues for settlement? (4)

A

1.chemical •e.g. abalone & crustose red algae • barnacles & conspecifics 2. light intensity 3. surface texture 4.presence of biofilm

22
Q

What does this picture show?

A

-older larvae are more desperate to settle

23
Q

What are the two systems of larvae dispersal?

A

-larvae retained= closed system -larvae dispersed= open system

24
Q

What determines the biogeography of coasts?

A

-Various processes acting at different temporal and spatial scales: 1.geological events & evolution 2.dispersal (life history + currents) 3. habitat (temperature & micro-habitat) =Combine to generate the patterns we observe in present-day species distributions.

25
Q

What did research show in terms of number of biorovinces in Australia?

A

5 -one type of division, based on qualitative studies

26
Q

What are the marine bioregions?

A

–IMCRA: Integrated Marine and Coastal Regionalisation of Australia

–24 provinces + 17 transitional bioregions based on geomorphology, oceanography & demersal fish

–also meso-scale bioregions nested within provincial bioregions

–Also exists at global level (Spalding et al. 2007) -finer scale is important for management

27
Q

Why are marine bioregions important?

A

•”provide spatial frameworks . . . for many aspects of natural resource management” •”contribute to an improved understanding of the wide variety of marine environments” •important input to planning and management decisions”