Article by Kaushiki Das (Karimganj College, Botany Department)
Climate change is one of the biggest problem of our times. The rising temperatures results in drought and forest fire are becoming more frequent. Rainfall pattern are shifting, glacier and snow are melting and the global mean sea level is rising. To mitigate the climate change we have to reduce the emissions linked with human activities.
Climate change is known to have an enormous impact on the plant biodiversity patterns and further impacts are expected in future. It is expected that the climate change will remain one of the major drivers 9f biodiversity patterns in future. Human actions are continuously triggering the sixth major mass extinction. Our earth has been changing and the distribution and abundance of many plants are also changing
The earth has experienced many changes in the climate since the plant first evolved. In comparison to the present day, this history has seen earth as cooler warmer dryer and wetter. And carbon dioxide concentration has been both higher and lower. These changes have been reflected by constantly shifting vegetation. For example forest communities dominating more areas in inter-logical period in period and herbaceous community dominating glacial periods.
Past climatic changes had been major drivers of speciation and extinction.
There is significant research focusing on the phenomenon of recent anthropogenic climatic changes or global warming. Focus is on identifying the coherent impact of climate change on biodiversity and predicting these effects in future.
EFFECT OF CARBON DIOXIDE.
Co2 concentration have been steadily rising for more than two centuries. Increased co2 have been implemented in vegetation thickening which affects plant community structure and function. Increased co2 can lead to increase in carbon nitrogen ratio in the leaves of plant changing herbivore nutrition.
EFFECT OF WATER.
A change in water availability would show a direct correlation to the growth rate and persistence of plant species in that reason. With less consistent, more intense rainfall events the water Avila will have a direct impact on the soil moisture. A decrease in soil moisture will have a negative impact on the plant growth.
EFFECT OF TEMPERATURE.
Increase in temperature raise the rate of many physiological process in the plants like photosynthesis. However extreme temperatures can be harmful.
A common hypothesis of scientist is that the warmer areas are, higher is the olant diversity
DIRECT IMPACT OF CLIMATE CHANGE.
.change in distribution
If climatic factors such as temperature or precipitation change in a region beyond the tolerance of the species, then distribution change of the species occurs. There are evidence that plant species are evidence that plant species are changing their ranges in altitude and latitude in response to the changing regional climate. Yet it is difficult to predict how species ranges change in response to the climate and spate this changes from all other man made environmental changes.
Changes in life cycle (Phenology)
The timing of phenological events such as flowering are often related to environmental variables changing environment are therefore expected to lead to change in life cycle events and these have been recorded for many species of plants.
Flowering times in British plants for example have changed, leading to annual plants flowering earlier than perennials and insert pollinated plants flowering earlier than wind pollinated plants. A recently published study has used the data recorded by Henry David to confirm affects of climate on Phenology of same species in the areas of Conord, Massachusetts.
Change in genetic diversity.
Genetic diversity is a mass contributor how an organism can evolve, the ecosystem would be much more succesptible to getting wiped out since each individual would be similar to the next. An absence of gene mutations and decrease in species richness greatly enhance the possibility of extinction.
INDIRECT IMPACT OF CLIMATE CHANGE
In Europe, the temperature and precipitation effects due to climate change can indirectly affect certain populations of plants.
The range of symbiotic fungi associated plants roots may directly change as a reault of altered climate, resulting in a change in the plant distribution.
A new grass into a region altering the fire regime and greatly changing the species composition.
A pathogen or parasite may change its interactions with a plant, such as a pathogenic fungus becoming more common in a area where rainfall increases
HIGHER LEVEL CHANGES.
Species respond in different manner to climate changes. Bird migration patterns already showing a change. If birds are leaving sooner this would decrease the pollination rates of some plants.
With certain species of plants having a disadvantage with a warmer climate, their insect herbivore would also be taken a hit. As these. Insect herbivore decrease, so will the higher species that eat those insects.