Dear Abhishek

In my opinion, if you put plants in functional groups, you will get better results.

To find the most effective factors, you can also use the principal component analysis. Because it provides effective factors of each region. In some areas, the effects of soil, topography, exploitation, etc. may be more than the effects of climate.

Hello Abhishek; I am thinking about the cactuses in the southwestern USA. As temperatures have risen, soil water budgets have declined. This is only one of the variables that covary. It isn't always clear which of the variables is the one that is effecting the plants. If you thought that temp was the range limiter, but in fact it was the water budget, you may misinterpret the data.

In another example, young plants are susceptible to freezing nights. One or two very cold nights during the winter limit the plants' upper elevation range limit. The water budget or the average summer temperature aren't the issue. Best regards, Jim Des Lauriers

Dear Abhishek

In my opinion, if you put plants in functional groups, you will get better results.

To find the most effective factors, you can also use the principal component analysis. Because it provides effective factors of each region. In some areas, the effects of soil, topography, exploitation, etc. may be more than the effects of climate.

Thank you @James Des Lauriers. Your point is valid, we may have misinterpreted the evidence.

Temperature is a very big factor. and in the whole range cliamatic changes can not be ignored. A variety of water components change with change in temperature and this may affect plants ione way or another

I think that various factors such as soil type, nutrient, and the presence of adequate breeding sites may prevent a range shift to some species of plants whereas support to others.