Constructing knowledge on Rock Outcrops

image130

Biodiversity and Ecosystem Services

Additional Information

 

Rock outcrop habitats have biodiversity adapted specially to the extreme habitat conditions. Seasonality has a major influence on the species. Several are restricted to specific microhabitats. Many function as terrestrial habitat islands that leads to speciation in all taxa.  


There is no comprehensive estimate of number of plants or animals from the rock outcrops in India. However, regional floristic studies have documented more than 150 endemic species and several new species from outcrop sites. The numbers are influenced by regional richness and hence outcrops in Western Ghats have high endemism, and have been called "hot-speks" in a biodiversity hot-spot. .

Learn More

Most outcrops appear lifeless during dry periods and they are often termed barren or wastelands. This is far from the truth. 

Elements of biodiversity

Flora

Microhabitats

Flora

image131

Vegetation is generally dominated by ephemeral herbs and geophytes. Cryptogamic vegetation is widespread. 

Fauna

Microhabitats

Flora

image132

A diversity of invertebrates, amphibians and reptiles are common on outcrops especially in monsoon period. Some adopt strategies to avoid desiccation in dry period. 

Microhabitats

Microhabitats

Adaptive strategies

image133

Each outcrop type has a diversity of "microhabitats". They differ mainly with respect to soil type, depth and moisture  and each has its specific vegetation. 

Adaptive strategies

Adaptive strategies

Adaptive strategies

image134

Plants and animals show peculiar adaptive strategies to survive on outcrops. Carnivory, desiccation tolerance, mat-forming ability are some of them. 

Ecosystem services

Adaptive strategies

Ecosystem services

Outcrops provide diverse ecosystem services to humans including water, fodder, minerals, pollinator

Outcrops provide diversity of ecosystem services to humans. They have played an important role in the development of human civilizations

Microhabitats

Most outcrops have a continuous layer of cryptogamic vegetation (lichens, cyanobacteria, mosses).

Cryptogamic crust

Most outcrops have a continuous layer of cryptogamic vegetation (with cyanobacteria, lichens, mossess) which supports other vegetation 

image135

Rock pools

Depressions of various sizes filled with water either seasonally or permanently are common on outcrops.

They have hydrophytic vegetation.  

image136

Ephemeral Flush Vegetation

EFV is seen in slightly sloping areas where water continuously seeps through. The characteristic vegetation includes bladderworts and Eriocaulons. 

image137

Rock Crevice

Crevices in the rocks could be very deep and are rich in humus and soil. They offer safe sites for many geophytes and perennial herbs.  

image138

Caves

Some outcrops have deep caves inhabited by special flora and fauna. Lateritic and limestone areas have deep caves formed due to weathering.

image139

Shallow Depressions

Shallow Depressions filled with soil are rich in species of Poaceae, Asteraceae, Balsaminaceae, Commelinaceae etc. 

image140

Monocot Mats

Mat-forming desiccation tolerant Tripogon (Poaceae) are seen on inselbergs and cliffs. The roots are closely interwoven into a mat, which can be easily lifted up. 

image141

Tree cover

Low stunted tree and shrub cover is seen in areas of deep soil on the outcrops. Generally it has species similar to the adjacent forest and scrub areas.

Rock outcrops and humans

Cultural services Petroglyphs

Provisioning services Waterbodies

Cultural services Petroglyphs

image142

Recent evidence of prehistoric petroglyphs and rock art in India indicates that humans have inhabited rock outcrop areas for several centuries. Ex. Bhimbetka, Konkan petroglyphs.

Cultural Services Shrines

Provisioning services Waterbodies

Cultural services Petroglyphs

image143

Many outcrops have small or large shrines and places of worship. Myths, anecdotes and stories that explain the strange and bizarre rock shapes are passed through traditional knowledge.

Provisioning services Waterbodies

Provisioning services Waterbodies

Provisioning services Waterbodies

image144

Natural and man-made ponds are commonly seen on rock outcrops. Historic Outcrop forts such as Raigad, Sinhagad, Gingee have water tanks. 

Recreational services Tourism

Supporting services Pollinator

Provisioning services Waterbodies

image145

Outcrops are often places of landscape tourism, wildflower tourism, recreational or adventure tourism.

Supporting services Pollinator

Supporting services Pollinator

Supporting services Pollinator

image146

Mass blooming of flowers on outcrops supports pollinators. The same pollinators help pollination of crops and orchards.

Supporting services Nutrients

Supporting services Pollinator

Supporting services Pollinator

image147

Apart from water, outcrops are known to function as catchments for nutrients. The nutrients fixed by vegetation are washed into soil in the surrounding area.