Species distribution

Question 1

species distribution definition

Answer 1

The distribution of a population that describes its spatial location, the area over which it occurs.

Species distribution is dynamic and complex with different scales and timelines

Question 2

Niche theory

Answer 2

The interaction between biotic and abiotic factors and dispersal abilities defines a species niche.
This is visualised in a BAM diagram (Biological,Abiological,Movement diagram -see notes)

A realised niche is shaped by multiple factors and in n-dimensional space from a fundamental niche

Question 3

Collecting and filtering data

Answer 3

Methods: research surveys,museum records, more tech advanced remote surveys camera traps and citizen sampling

Different collection methods can introduce bias

Reduce bias using:

Data partitioning – half the data is used to train and calibrate a model and the other half to test reliability/accuracy e.g. Brown bears study

Question 4

Species distribution modelling is used to make predictions
There are 3 key types:

Answer 4

Correlative modelling –realised niche is modelled, modelling the distribution as a factor of environmental conditions e..g. max ent.

Mechanistic modelling – utilises species physiological data to understand environmental processes influencing distribution to do future modelling

Ensemble modelling – combines models to minimise bias

Question 5

Factors that influence/limit species distribution

Answer 5

PH, food and water availability etc.

Question 6

bipolar species distribution

Answer 6

e.g. grass species C. canescens (Villaverde et al 2017)
Moves across equator by mountain bridge
Direct long distance seed dispersal by birds

Question 7

Abiotic factors: climatic, edaphic, social

Answer 7

Abiotic Factors can be climactic, edaphic or social

Climatic – humidity or temp related
Edaphic – soil ph and nutrient related
Social - ?

Question 8

Edaphic example: soil

Answer 8

Snowdon lily has an arctic alpine distribution over glacial refuge areas across mountain areas worldwide that remained cold enough after ice age

Question 9

Endemism

Answer 9

• Endemic – A distribution limited to a small geographic area
• Islands often have high levels of endemism due to longterm isolation
• Endemism is lower in UK due to at least three Ice-Sheets have covered the UK and Ireland; The Anglian, The Wolstonian, and the Devensian connecting the islands.

*Repeated Glaciation events have meant the climate wasn’t stable and isolated enough over long periods of time to allow for endemic species to speciate. The Distribution of Endemic Species displays a northwestern bias, usually being found in upland areas and islands.

Question 10

Biotic factors

Answer 10

Biotic Factors include: disease, predation, inter- and
intra-specific competition, as well as a species’
evolutionary history.
Anthropogenic factors may also be included under
this umbrella

Question 11

Example of biotic factors impacting species distribution

Answer 11

The European Hedgehog (Erinaceus europaeus) has declined in Britain due to biotic factors.
Namely Habitat Loss, Predation and competition
Changing agricultural practice has removed large portions of
its traditional Habitat (Hedgerows)
Badger numbers, both predators and competitors, have increased.

Question 12

Mismatch between niche-model and geographic distributions

Answer 12

Due to:
Higher persistence ability lower dispersal ability
More frequently occupy environments outside their niches

Question 13

Why is it important to understand species distribution?

Answer 13

Settling land-use conflicts

Conservation prioritisation

Urban management

Question 14

Kuta plant

Answer 14

Climate change is causing south ward movement of distribution
Loss of key cultural weaving plant
(Bond et al 2019)

Question 15

Species distribution and human interaction example

Answer 15

Range of venomous snakes is changing in Iran and will soon include many villages – awareness and education is necessary (Yousefi et al 2020)

Question 16

Species distribution for prediction and prevention of invasive species example

Answer 16

e.g. himalayan balsam an invasive specie alters mycorrhizal interactions in native plants
Mapping suitable habitats, biotic interactions and dispersal capacity of the species can be used to identify areas at risk

Question 17

Species distribution for socio-economic stability example

Answer 17

e.g. understanding of fish distribution – North Sea cod abundance will reduce whereas Sea Bass and Red Snapper will increase so markets will need remodelling (Copernicus 2019)

Question 18

Distortion of the food web can result from species redistribution

Answer 18

Especially an issue in changed migration ranges
Can cause home ranges to overlap – e.g. grizzly and polar bears now more likely to crossbreed – Pizzly Bears

Question 19

Human impact on species distribution

Answer 19

e.g. Arbutus unedo brought to Ireland by copper miners from spain in the bronze age

Question 20

Key empirical results

Answer 20

latitudinal gradient
elevational gradient
negative anthropogenic influence
high extinction rates
island biogeography theory
decrease in endemic species and increase in widespread species

Question 21

challenging and understudied distributions

Answer 21

Deep sea species

Cryptic species

Deep seafloor microbial species

Extremophiles

Question 22

applications of citizen science and AI

Answer 22

Issue with citizen science is its provided by non-scientists

Mosquito dashboard is an app where you can record where you’ve been bitten and which species bit you

Question 23

Possible future improvements

Answer 23

Improved tracking sensors

Environmental DNA – collected from soil can help to determine cryptic and invasive species

Question 24

Summary

Answer 24

• Species distribution is diverse, and dynamic being affected by biotic, abiotic and dispersal factors from niche theory.
• Consideration of all factors and interaction with each other is key to construct accurate models and estimation.
• Plasticity and dispersal ability of species will determine either evolution, speciation and species range sift.
• Species distribution models will help us to plan mitigation actions against climate change for industry, people and wild organisms.
• Developing technology and modeling will increase the practicality and accuracy of species distribution models.

Question 25

GBIF best data set of world-wide species distribution

Answer 25

GBIF—the Global Biodiversity Information Facility—is an international network and data infrastructure funded by the world’s governments and aimed at providing anyone, anywhere, open access to data about all types of life on Earth. https://www.gbif.org/