Introduction to soil biodiversity

Question 1

What percentage of species on Earth are soil-dwelling?

Answer 1

59% (±15%)

Question 2

Name two groups that comprise a substantial part of soil biodiversity

Answer 2

Bacteria and phages

Question 3

What are three major reasons that it is difficult to estimate soil species richness?

Answer 3

Limited data, variable methodologies, and geographic biases

Question 4

What are three major reasons of the importance of soil in international strategies for biodiversity conservation?

Answer 4

Role in supporting ecosystem services, resilience to environmental change, and sensitivity to global factors

Question 5

What did a 2015 study conclude about soil resources?

Answer 5

Majority of soil resource are in fair/poor/very poor condition due to human activity

Question 6

What did a 2015 study conclude about land?

Answer 6

33% of land is moderately to highly degraded

Question 7

What did a 2015 study conclude about topsoil?

Answer 7

25–40bil tonnes of topsoil is lost to erosion per year

Question 8

How long does it take to produce a metre depth of soil?

Answer 8

10,000 years (degradation>production therefore it is a non-renewable resource)

Question 9

How much carbon is stored in soil?

Answer 9

2.5 trillion tonnes (3rd largest carbon store)

Question 10

What do the UK government aim to do by 2030?

Answer 10

Ensure sustainable management of soil and establish sufficient data to understand the current state of soil health

Question 11

What are the four classifications of soil-dwelling organisms (based on body size)

Answer 11

Microflora, microfauna, mesofauna, macrofauna

Question 12

Give two examples of microflora

Answer 12

Bacteria and archaea

Question 13

Give two examples of microfauna

Answer 13

Nematodes, protozoa

Question 14

Give an example of mesofauna

Answer 14

Microarthropods

Question 15

Give three examples of macrofauna

Answer 15

Worms, termites, millipedes

Question 16

Describe the microbial biomass in soil

Answer 16

Most abundant and diverse group in soil. Primary consumers.

Question 17

What are the four primary roles of the soil microbial biomass?

Answer 17

Breakdown of complex organic material, nutrient transformation, structural stability, symbiotic relationships (mycorrhizal fungi and N fixing)

Question 18

Describe soil fauna

Answer 18

Secondary and high order consumers

Question 19

Give four examples of fine-scale abiotic properties of soil

Answer 19

Porosity, water, temperature, pH

Question 20

What is rhizodeposition?

Answer 20

The deposition of amino acids and sugars in the soil adjacent to the plant root that stimulates microbial abundance and diversity

Question 21

What are the two main plot-to-field scale categories

Answer 21

Resource quality and human disturbances

Question 22

What are the two categories of soils in terms of resource quality?

Answer 22

Mull soils and mor soils

Question 23

Describe mull soils

Answer 23

Fertile, neutral pH soils with high abundance of bacteria and bacterial-feeding fauna and earthworms

Question 24

Where and how are mull soils produced?

Answer 24

Deciduous forests with high litter nitrogen, low lignin and phenolics (protects plants from herbivores)

Question 25

Describe mor soils

Answer 25

Infertile, acidic soils. Absence of earth worm, high abundance of fungi, microarthropods/enchytraeids (annelids).

Question 26

Where and how are mor soils produced?

Answer 26

Coniferous forests with low litter nitrogen, high lignin and phenolics

Question 27

Give three examples of human impacts on soil

Answer 27

Intensive agricultures, climate change, increasing aridity