Macroecology

Question 1

Definition

Answer 1

The statistical and theoretical study of generalised ecological patterns at large spatial and temporal scales

The interaction between ecology and geography examining patterns that span continents

Vast amounts of data collated to determine the trends of life atmacroscopic levels

Highly theoretical – essential for largescale understanding of human impact on ecosystems

Includes Historical biogeography

Question 2

Why is it important?
Understanding the past helps us to predict the future

Answer 2

Macroecology aims to understand the principles of biodiversity and how things such as climate, anthropological interference and ecological dynamics come together to determine distribution of species. Aiming to understand large scale migration patterns and species interactions to predict species distribution changes in the future.

Question 3

Methodology and approach

Answer 3

Macroecology has a largely statistical basis

Datasets take up many forms:
- Maps
- Correlations/Associations
- Temporal
(and more)

Statistical softwares (R, SPSS, Stata,etc.) and GIS softwares are essentialin the study of modern macroecology.Large-scale ecology has some methodological parameters to consider.

Question 4

Dimensions

Answer 4

Time, space, taxonomy central to ecological study – to be macroecological at least one of these must be large ranging data

Question 5

Metrics of scale

Answer 5

consider grain and extent

Question 6

Reductionist vs emergent approach

Answer 6

The Reductionist Approach (bottom-up)

Finds observational trends
+ The traditional approach to large-scale ecology
+ Helpful in understanding inner workings of a system

Some systems are too complex for this approach:
- It may ignore external influences that affect a character
- upscaling can result in Jensen’s Inequality
- Scaling up non-linear, heteroscedastic data is often ineffective. Approximate at best

Macroecology aims to focus on emergent patterns to understand the origin of the trends we see in nature

Emergent approach (top-down )
employs top-down data analysis considering the set as a whole

Question 7

How is it studied

Answer 7

Observational data Principal for finding certain trends (e.g. patterns of species at geographic scales)

Natural experiments/ experiments in nature
– natural and human caused events that cause changes in a system e.g. earthquakes or introduction of invasive species
- NSEs and NTEs (Natural Snapshot/Trajectory Experiments)

Manipulative Experiments- Controlled experiments. Not as common, but applicable to field and laboratory-based microcosms

Question 8

Statistical considerations

Answer 8

Lack of control variables within observational and natural experiments may require different approaches.
- Null Hypothesis Tests
- Information-Theoretic Approach using models
- Multivariate Approach

Acknowledging autocorrelation is important
- Phylogenetic – due to similar species genetics
- Spatial – due to overlap

Question 9

Patterns: Change in traits along spatial and temporal scales

Answer 9

Macroecology explores how characteristics of species change across geographic ranges and evolutionary time scales.
One example of this is the latitudinal diversity gradient

Question 10

Another example is how species morphology changes across geographic range

Answer 10

Bergmann’s rule: individuals in colder parts of a species geographic range are often large

Allen’s rule: individuals in colder parts of a species geographic range often have shorter, thicker limbs.

Question 11

Patterns: covariation of attributes

Answer 11

Understanding how two traits change together is important in macroecology.

One example is the covariation of population density and individual body size.
- In general, population density decreases with body size.
- As body size is linked to metabolic rate this suggests that different species use a similar amount of energy as others in their population.

Metabolic theory suggests that metabolic rate connects many ecological patterns.

Question 12

Metabolic theory

Answer 12

Kleiber’s law:
- Mammalian metabolic rate scales to ¾ power of its mass
- Greater rate of resources used by individuals of smaller metabolic rate means there is less space in the nice
- so smaller organisms and organisms with higher body temp have higher metabolic rate

Bergmanns rule example : bats
Morphological difference between different sites
Dispersal barriers lower so found where best suited
Allopatric sites studied with a 6.9 degrees c variation in temp
Colder temp determined larger size

Question 13

Latitude and longitude example of latitudinal diversity gradient (LDG)

Answer 13

Coral species are connected across two oceans
Richness is higher in the east
Bell curve due to many widely dist species or many specific location species
Species richness due to easterly ocean currents so richer in east than west
Coral triangle thought to contribute

Question 14

Temporal macroecology example orchids

Answer 14

5,000 taxa of Orchidoidae, first identified 112 Mya in Australia.
Variation in distribution
Increased speciation primarily due to cooling cycles

Inconsistent rate of species accumulation
Correlation between speciation rate and cooling temp?

Link between speciation and coldness – higher speciation rate in cold areas?

Question 15

Applications

Answer 15

Maintaining Ecosystem function
-Effect of climate change on global fisheries potential
-Range shifts leading to unequal distribution
-Impacts on fishery-dependent communities
-Food availability and security

conservation and maintaining biodiversity
- by identifying large-scale patterns

Question 16

Practical applications: ecosystem function has commercial value

Answer 16

-Effect of climate change on global fisheries potential
-Range shifts leading to unequal distribution
-Impacts on fishery-dependent communities
-Food availability and security

e.g. Global fisheries require maintenance of fish stocks
- Range shifts due to climate change can impact fishing quota and political boundaries can result in food source instability.
- Computational models beneficial in political fishery agreements – advanced modelling could allow for negotiations before issues arise

Question 17

Limitations of models

Answer 17

For models to be accurate enough data collection must be broad and large sets which have not been as possible in the past

Establishing temporal baselines and future directory such as in the context of human impact is difficult (graphs on right show that human impact precedes human monitoring)

Lack of continuity between past data sets

Question 18

The future of macroecology: data collection and analysis

Answer 18

developments in tech will allow the large scale data sets necessary to study macroecology effectively

• Developments in satellite imaging to create detailed maps of the earth’s surface e.g. LiDAR - Light Detection and Ranging using laser pulses to measure the distance to the earth’s surface and create 3D models of terrain and vegetation structure.
  ^ These satellite maps show vegetation health and cover + allow us to access areas not previously analysed improving prediction accuracy, also makes it possible to access areas which are hard to reach for scientists

AI to collect and collate large vol of data swiftly resulting in larger available data sets e.g. mapping penguin colonies using an ai

Developments in artificial intelligence will allow large volumes of data to be in analysed in seconds and continuously updated.

The ease of data analysis and collection will increase the accessibility and will therefore increase the available datasets.

For example
New colonies of emperor penguins discovered by students at Stirling High School using satellite mapping imagery from the European Space Agency’s Copernicus Sentinel-2.
Dwyer (2021)

Question 19

How will these developments affect macroecology as a whole?

Answer 19

-The pace of macroecological research is set to increase.

-This should motivate the integration of the different disciplines of science with the common goal of conservation.

-Help to eliminate the reputation macroecology has for being too abstract to do any real good.

Question 20

Summary

Answer 20

-Macroecology is important for understanding trends in our biosphere and its health, particularly in a key period of human influence.

-There are two approaches in ecology: emergent and reductionist. Emergent is more applicable in this field but reductionist is important too.

-Statistical method is key when considering the lack of control variables and presence of autocorrelation.

-Patterns can be changes in traits across spatial or temporal scales, such as the latitudinal diversity gradient.

-Applications include preserving biodiversity and ecosystem function.

-Technological developments will allow macroecology to evolve as a discipline

Question 21

Manipulative experiments – microcosms in lab for data collection: How do you go about creating a microcosm?

Answer 21

How do you go about creating a microcosm – how many species need to be involved to provide useful representation of an ecosystem?

Useful in the context of microorganisms not used for macroorganisms

Change in parameters as the result of natural events – can be treated as an experimental form outside the lab – one aspect has changed.

Spacial autocorrelation testing available

Question 22

Macroecological exceptions are many –

Answer 22

however certain macroecological factors specific to those areas specifically may be causing this.

Question 23

In a world with limited funds and many conservation issues how can macroecology study help?

Answer 23

Beneficial in global legislation planning

Justifies grant requests – due to potential large impact

Due to rapid changes at present predictions will help to provide general guidance necessary to respond fast.

Question 24

Metabolic theory maximum threshold cutoff point?

Answer 24

Some species have lower thresholds than others

Linear metabolic increase until plateau where organism enzymes denature and it dies

Question 25

Can we find a way to predict fish stock levels before intensive human fishing?

Answer 25

Sedimentalogical data could help to derive previous fish stock densities before intensive human fishing activities – not easy to get one solid number due to many potential influences. Forecasting models backward using population density information from current records.

Utilising hunting records, shooting, fishing and trapping records can provide accurate data for conservation.