Phenology is thus concerned with chronological patterns in nature. When do leaves appear in spring, when do leaves change colour in the autumn? When do bears wake from their hibernation, when do migrating birds arrive in Sweden? Much of what we regard as the seasons are precisely these changes in nature - the coltsfoot comes into flower, and we feel that spring is on the way. Apart from describing the timing of natural events, phenologists try to understand what governs these and what happens when these times change.
The motive behind a phenological network is to document the changes in seasonal patterns all over the world, and our need to understand these effects. The phenological network shall construct a database on the basis of individual observations and data collected from field and research stations. Together, these data will be of great importance for our ability to deal with the effects of climate change.
One of the effects of the ongoing climate change is that it will be warmer on earth and the systems used by plants and animals to regulate their annual cycles will therefore change. This will pose the greatest challenge for plants since these cannot move but must adapt to the conditions prevailing in their habitats. Many plants are also dependent on insects for pollination and on birds to spread their seeds. At present, we know very little of how these interactions between insects, birds and plants will be affected by climate change.