6 FUNCTIONAL GROUPS

Question 1

How organisms respond to various ecological factors and in turn how these responses affect ecosystem functioning is fundamental to discerning ecological what?

Answer 1

Ecological consequences of change

Question 2

What do taxon based approaches compare? What do they often use? Why don’t identified patterns necessarily point to causation/provide mechanistic understanding from a functional standpoint?

Answer 2

• Compare species assemblage in relation to environmental conditions
• often using multivariate statistical approaches
• any identified patterns don’t necessarily point to causation or provide mechanistic understanding from functional standpoint bc taxonomic position of a species isn’t a reliable indicator of ecological role of species

Question 3

What is the focus in trait based approaches?

Answer 3

• How the components of biodiversity influence ecosystem properties
• Therefore are touted as offering greater mechanistic understanding that can be applied more generally.

Question 4

What are functional traits?

Answer 4

Those that define species in terms of their ecological roles; how they interact with the environment & other species.

Question 5

What are biological species traits? What do they relate to?

Answer 5

The attributes of a species.
They relate to morphological, biochemical, physiological, structural, phenological, behavioural, and/or any other functionally relevant life-history features of the organism

Question 6

What is a functional effect trait? What can they help us understand?

What is a functional response trait? What can they help us understand? What is functional redundancy?

Answer 6

• Any trait which alters specific community or ecosystem properties. They can help us understand organism-sediment interactions, how species effect ecosystem processes, and the delivery of ecosystem functioning.
• Any trait responding to external forcing that alters the performance or fitness of an individual, e.g. via its effects on growth, reproduction and survival. Can help us understand how communities may change in resp to environmental change.
• Functional redundancy = overlap in functional capability (several species contribute/respond in the same way as other species)

Question 7

What is a functional group?

Answer 7

A set of organisms sharing similar responses to the environment (e.g. temp, salinity, nutrients, competition) / have similar effects on ecosystem processes (e.g. bioturbation) / functioning (e.g. productivity, nutrient cycling)

Question 8

What is a good strategy for understanding effects of functional diversity on ecosystem processes?

Answer 8

Nesting functional response groups within functional effect groups
Unifies the processes of community assembly and biodiversity effects on ecosystem function.

Question 9

What are some examples functional trait category/associated categorised trait modality pairings?

Answer 9

body mass -> biomass, biovolume or other size measurement

morphology -> shape, structure & network properties

larval type -> planktotrophic, lechithotrophic, direct development

living habit -> sedentary, errant, attached, tube or burrow dweller

activity -> periodicity (occasional, cyclic, continuous) or mode (e.g. bioturbation, reworking modes)

feeding habit -> detritivore, herbivore, carnivore, omnivore, scavenger, predator, parasitic

resource capture -> jawed, siphon, tentaculate, pharynx, radula

mobility -> sedentary, semi-mobile, mobile

movement -> byssus, swimmer, rafter/drifter, crawler, burrower

environmental position -> pelagic, epibenthic, benthic, physiological requirements

Question 10

Why is size (typically biomass) not necessarily a reliable indicator of species functional distribution?

Answer 10

reflects a range of other factors, like life stage and recent environmental conditions.

Question 11

How do tube building species/species with protruding physical structures act as sediment stabilisers?
How do species that disproportionately mix the sediment profile act as sediment destabilisers?

Answer 11

• act as baffles and redirect current flow, and large stands of species can raise the benthic boundary layer
• can increase porosity and erodibility of the sediment surface

Question 12

What are the different functional feeding groups? (6)

Answer 12

• engulfer
• shredder
• piercer
• scraper
• collector
• filterer

Question 13

What are the 6 trophic feeding groups?

Answer 13

suspension
deposit
carnivore
omnivore
herbivore

Question 14

What are the 7 types of bioturbation?

Answer 14

1. epifaunal
2. surficial modifiers
3. biodiffusers
4. gallery biodiffusers
5. upward conveyors
6. downward conveyors
7. regenerators

Question 15

What is the difference between classification and ordination approaches to group species into functional groups?

Answer 15

Classification techniques: tend to assign species on assumed a priori defined species roles & tend to be based on evidence from lit & expert knowledge. Groups similar species based on assumed traits.

Ordination: studies tend to use continuous rather than categorical traits & identify functional group membership using statistical techniques based on measured data. Groups similar species based on measured traits.

Question 16

What is the requirements of summary functional effect descriptors in order to be useful, but are rarely filled?

Answer 16

• need to have been derived using systematic selection process
• sufficiently comprehensive
• to provide acceptable explanatory power for observed species contributions to ecosystem function

Question 17

What is an example of how species can appear to belong to the same functional group, when in fact being functionally distinct?

Answer 17

Resource partitioning
Diff bivalve species share same mode of reworking (surficial modifiers) and feeding mode (suspension feeding), but diff in body size and occupy v diff depths within sediment profile.

Question 18

What is a commonly used marker of trophic position?

What is their advantage over gut content analysis?

Answer 18

Analysis of stable isotopes
They reflect tissue assimilation from prey
Aren’t hindered by stomach content biases

Question 18

What is a commonly used marker of trophic position?

What is their advantage over gut content analysis?

Answer 18

Analysis of stable isotopes
They reflect tissue assimilation from prey
Aren’t hindered by stomach content biases

Question 19

Why could the food availability hypothesis, regarding sandy and muddy sediments dominated by suspension and filter feeders due to food availability, be incorrect?

Answer 19

i) water column data revealed more organics in water column above mud, but still no suspension feeders
ii) boundaries betw suspension feeding and deposit feeding often too sharp to reflect food supply gradients
iii) hard substrata e.g. rocks in otherwise muddy sediments were not necessarily covered in suspension feeders

Question 20

What did rhoads and young hypothesise regarding deposit and suspension feeders?

Answer 20

• deposit feeders negatively effect suspension feeders, excluding them from mud habitats
• showed relationship between high sediment turnover and high water content

Question 21

Do deposit feeders increase erosion? Use the Rhoads and Young experiments to explain; they thought that deposit feeders may create much finer sediments that, in turn, would clog the filtering apparatus of suspension feeders.

Answer 21

YES

• greater resuspension leading to turbidity above the burrowed sediment than over the unburrowed sediment
• during erosion of loose granular sediment, roughness of the sed surface increased, producing turbulence, which accelerated the erosion process

Question 22

Does sediment resuspension benefit suspension feeders? Think about growth of juvenile mercenaria mercenaria on trays at different elevations from seabed.

Answer 22

NO

growth of juvenile m mercenaria is inhibited near the unstable sediment-water interface

Question 23

What is the trophic group amensalism hypothesis? Think about suspension & deposit feeding trophic groups.
What did their rationale include?

Answer 23

Rhoads and Young suggest that there are interactions betw suspension and deposit feeding trophic groups that lead to exclusion of one group over the other.

1. deposit feeders create much finer sediments that clog the filtering apparatus of suspension feeders
2. deposit feeders would consume settling larvae
3. deposit feeders would cover any surfaces to which suspension feeders would attach

Question 24

Recent work shown that expression of functional ... isn't fixed and occurs at scale of ... and in response to ...

Answer 24

traits individual context

Question 25

The functional ... of organisms depend on ... in the aquatic/benthic ... area, behaviour reflects ... rates, while in the ... layers, behaviour is largely focused on ... and or modifying flow rates (tubes, pits, mounds, burrow, ventilatory activity).

Answer 25

``` behaviour location boundary flow sediment constraining ```

Question 26

As organism behaviour is intimately associated with ... and horizontal components of benthic ..., the realised ... role of an individual is likely to reflect the ... an individual has to contend with that reflect the circumstances within which an individual operates.

Answer 26

ecospace functional tradeoffs

Question 27

Instead of defining species by a single trait category, info from ... traits define the ... group. these ... group typologies are very ..., giving rise to many more functional groups

Answer 27

multiple functional functional detailed

Question 28

Bioturbation potential of a community provides estimate of the potential of a community to... BPc provides means to estimate the extent to which benthic communities are likely to affect ... properties that underpin ecosystem ...

Answer 28

bioturbate ecosystem functioning

Question 29

What is biological trait analysis? uses multivariate ordination...

Answer 29

technique that allowed functional group allocation to be based on extended series of life history, morphological and behavioural characteristics. uses multivariate ordination to describe patterns of biological trait composition over entire assemblages.

Question 30

nMDS is based on...

Answer 30

the rank similarities of samples and produces ordination plot showing relative differences in biological trait composition. best for providing general picture of functioning, whilst FCA and Col had greater power to detect change but were much harder to interpret.

Question 31

What attributes does a functional group need to have?

Answer 31

1. based on common attributes rather than phylogentic relationships 2. incorporate interactions between org's and their environment 3. relevant to interest or purpose of study 4. supported by empirical evidence 5. accompanied by caveats (limitations, scale, context etc.)