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

Lichens what are they….?

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.

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.

Ecosystem services and Lichens

Lichen and Ecosystem services

The set of ecosystem functions that

are useful to humans are defined as

ecosystem services.

Lichens: Soil formation

Supporting services

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

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

Lichens: Food, fodder and Habitat

Provisioning services

Cetraria islandica

Cladonia rangiferina

Macrochlamys indica

Cladonia (China)

Invertebrate herbivory

Nesting material

Parmelioid

lichens

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)

Lichen : efficient biomonitors/ bioindicators

Zoo-anthropogenic

Disturbances

Pollutants Metals

C,N,S

PAHs

Change in diversity

Regulating services

Pyxine cocoes

Lichenometry: Glacial recede/ climate change

Regulating services

Lichen : Dyes and Recreational value

Parmelia sulcata

Cultural services