I wanted to learn how the seasonal variation relate to climate change. The best samplimg methods are required. Therefore, any references or suggestions are welcome. Thank you
In my opinion it directly depends on which exact indices you would like to estimate in climate (temperature, humidity etc.) and which variables can be used as predictors. I would suggest using linear regression in case of continuous depending variable or multinomial regression in case of categorical depending variable (ie. stable, decreased, increased etc.).
You can also estimate the changes depending on time.
You can easily measure seasonal variation. But to demonstrate the effect of 'climate change' you would need to have sampled in earlier glacial periods. But obviously this is not possible. The best you can do at this time is to correlate biodiversity with microclimate and suggest what might happen if the climate changed significantly. Sampling techniques include random quadrats with replication in different areas and ecosystems and then analysis using ordination and permanova :)