Lichens provide several important ecosystem services: 1) Lichen-dominated biological soil crusts play a key role in soil formation, mineral cycling, and water retention by increasing infiltration and moisture retention. 2) Some lichens are used as a food source for humans and animals, provide nesting materials, and create habitat. 3) Lichens produce valuable secondary metabolites that have applications in medicine and human health. 4) Lichens are effective bioindicators of pollution and climate change due to their sensitivity, and can be used to monitor environmental conditions via changes in diversity.

1. Lichen Biodiversity: Ecological functions and
role in Ecosystem services
Dr. HIMANSHU RAI1, 2
MRD, Project Principal Investigator
Uttarakhand State Council for Science and Technology,
Department of Botany, Pt. L.M.S Govt PG College,
Rishikesh (Dehradun)-249201, INDIA

2. Lichens what are they….?

3. Lichen: Growth forms
Crustose ( crust like)
Ioplaca spp. Leprose ( Powdery crust)
Lepraria spp.
Foliose ( Leaf like)
Flavoparmelia spp.
Fruticose ( Shrub like)
Ramalina spp.
Dimorphic
Primary thallus squamulose
Secondary thallus
Fruticose
Caldonia spp.

4. Lichen: Habitat subsets
Corticolous ( on bark)
Terricolous ( on soil)
Ramicolous ( on twig)
Omnicolous ( on man made structures)
On iron railway sleepers Heterodermia galactophylla
Parmotrema reticulatum
Bulbothrix meizospora
Saxicolous ( on rock)
Xanthoria elegans
Muscicolous ( on mosses)
Hypotrachyna spp.
Ramalina spp.

5. Ecosystem services and Lichens
Lichen and Ecosystem services
The set of ecosystem functions that
are useful to humans are defined as
ecosystem services.

6. Lichens: Soil formation
Supporting
services

7. Lichens: Mineral cycling
 Lichens are major constituent of cryptogamic biological
soil crusts (BSCs) in arid/ water delimited habitats and
play important functional role in maintaining the fertility
of soils trough extensive contribution in nitrogen
dynamics of soil sink.
 Lichen dominated BSCs as a constituent of cryptogamic
ground cover (CGC) along with cryptogamic plant
cover (CGC) constitute an global continuum of
cryptogamic cover acting as major sink of atmospheric
CO2 and nitrogen which accounts for about 7% of net
primary production and about half of biologically fix
nitrogen in terrestrial biomes.
Stereocaulon spp.
Peltigera spp.
 Species of cyanolichens i.e. Collema, Peltigera,
Leptogium and Stereocaulon are key elements
in nitrogen dynamics of soil. Heterocystous
cyanobacteria i.e. Nostoc, Crococcus and
Scytonema in cyanolichens metabolize
atmospheric N2 to biologically active nitrogen.
 Lichens along with fixing atmospheric N2 also
act as CO2 sink and produce carbon and
nitrogen containing organic compounds e.g.
amino acids, carbohydrates and extracellular
polymeric substances.
 These products and cryptogamic biomass, are
consumed by plants, animals and other
organisms in the surrounding ecosystem or
removed by erosion or runoff.
 Lichens are able to fuel food webs by
photosynthesis and nitrogen fixation, which is
particularly important in water delimited habitats
(deserts, alpine barren lands, cold deserts,
poles and glacial terminal moraines) and other
terrestrial environments with low abundance of
organic nutrients.
Supporting
services

8. Water retention and cycling: Lichen dominated BSCs
 Lichen dominated BSCs plays significant role in
soil hydrological cycle influencing the overall
biomass accumulation is soil crusts.
 There are many feedback loops among crust
and soil features that can influence local
hydrologic processes.
 Lichen dominated soil crusts increases surface
roughness which slows water and, thereby
increases soil infiltration, thus accumulated
greater soil moisture allows for greater crust
carbon and nitrogen fixation, which results in
greater crust biomass, which increases soil
surface absorptivity, soil aggregates, soil
micropore formation and stability and, up to a
point, also increase soil moisture retention.
 The loop is closed as these factors in turn lead
to greater crust biomass resulting eventually,
increase in soil biota, soil fertility, vascular
vegetation structure which further facilitates
water infiltration
Supporting
services

9. Lichens: Food, fodder and Habitat
Provisioning services
Cetraria islandica
Cladonia rangiferina
Macrochlamys indica
Cladonia (China)
Invertebrate herbivory
Nesting material
Parmelioid
lichens

10. Lichen : Medicines and Human health
Provisioning services
Lichens produce a wide
array of both
Primary (intracellular)
metabolites : amino
acids, polyols,
carotenoids,
polysaccharides, and
vitamins.
Secondary(extracellula
r) metabolites : Lichen
acids
Lichen secondary metabolites are
derived from three chemical
pathways:
Shikimic acid pathway
pulvinic acid derivatives (yellow
pigments)
Mevalonic acid pathway
terpenes
Acetate-polymalonate pathway
depsides, depsidones, usnic acid,
anthraquinones, xanthones,
aliphatic acids (majority of lichen
compounds)

11. Lichen : efficient biomonitors/ bioindicators
Zoo-anthropogenic
Disturbances
Pollutants
 Metals
 C,N,S
 PAHs
Change in diversity
Regulating services
Pyxine cocoes

12. Lichenometry: Glacial recede/ climate change
Regulating services

13. Lichen : Dyes and Recreational value
Parmelia sulcata
Cultural services