Phenology

Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation).

The word is derived from the Greek φαίνω (phainō), "to show, to bring to light, make to appear"[6] + λόγος (logos), amongst others "study, discourse, reasoning"[7] and indicates that phenology has been principally concerned with the dates of first occurrence of biological events in their annual cycle.

[14] The term may not have been common in the decades to follow, as in an article in The Zoologist of 1899 describing an ornithological meeting in Sarajevo, where "questions of Phaenology" were discussed, a footnote by the Editor, William Lucas Distant, says: "This word is seldom used, and we have been informed by a very high authority that it may be defined as "Observational Biology", and as applied to birds, as it is here, may be taken to mean the study or science of observations on the appearance of birds".

Observations of phenological events have provided indications of the progress of the natural calendar since ancient agricultural times.

Many cultures have traditional phenological proverbs and sayings which indicate a time for action: "When the sloe tree is white as a sheet, sow your barley whether it be dry or wet" or attempt to forecast future climate: "If oak's before ash, you're in for a splash.

This program, originally started by Wells W. Cooke, involved over 3,000 observers including many notable naturalists of the time.

In Japan and China the time of blossoming of cherry and peach trees is associated with ancient festivals and some of these dates can be traced back to the eighth century.

Between 1850 and 1950 a long-term trend of gradual climate warming is observable, and during this same period the Marsham record of oak-leafing dates tended to become earlier.

[20] After 1960 the rate of warming accelerated, and this is mirrored by increasing earliness of oak leafing, recorded in the data collected by Jean Combes in Surrey.

Over the past 250 years, the first leafing date of oak appears to have advanced by about 8 days, corresponding to overall warming on the order of 1.5 °C in the same period.

[26][27][28] National recording was resumed by Tim Sparks in 1998[29] and, from 2000,[30] has been led by citizen science project Nature's Calendar [2], run by the Woodland Trust and the Centre for Ecology and Hydrology.

Latest research shows that oak bud burst has advanced more than 11 days since the 19th century and that resident and migrant birds are unable to keep up with this change.

[34] This task is conducted by the secretary of the Grand Council of Geneva (the local parliament), and the opening of the first leaf is announced publicly as indicating the beginning of the Spring.

In eastern North America, almanacs are traditionally used by farmers for information on action phenology (in agriculture), taking into account the astronomical positions at the time.

A noteworthy example of the use of remote sensing based phenology is the work of Ranga Myneni[46] from Boston University.

This is mainly due to the limitation of current space-based remote sensing, especially the spatial resolution, and the nature of vegetation index.

Many species experience changes in life cycle development, migration or in some other process/behavior at different times in the season than previous patterns depict due to warming temperatures.

Phenological mismatches means the loss of many biological interactions and therefore ecosystem functions are also at risk of being negatively affected or lost all together.

Phenological mismatches will effect species and ecosystems food webs, reproduction success, resource availability, population and community dynamics in future generations, and therefore evolutionary processes and overall biodiversity.