Phenology
Encyclopedia
Phenology is the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate. The word is derived from the Greek
φαίνω (phainō), "to show, to bring to light, make to appear" + λόγος (logos
), amongst others "study, discourse, reasoning" and indicates that phenology has been principally concerned with the dates of first occurrence of biological events in their annual cycle. Examples include the date of emergence of leaves and flowers, the first flight of butterflies and the first appearance of migratory
birds, the date of leaf colouring and fall in deciduous trees, the dates of egg-laying of birds and amphibia, or the timing of the developmental cycles of temperate
-zone honey bee colonies. In the scientific literature on ecology
, the term is used more generally to indicate the time frame for any seasonal biological phenomena, including the dates of last appearance (e.g., the seasonal phenology of a species may be from April through September).
Because many such phenomena are very sensitive to small variations in climate
, especially to temperature, phenological records can be a useful proxy
for temperature in historical climatology
, especially in the study of climate change
and global warming
. For example, viticultural records of grape harvests in Europe have been used to reconstruct a record of summer growing season temperatures going back more than 500 years.
In addition to providing a longer historical baseline than instrumental measurements, phenological observations provide high temporal resolution
of ongoing changes related to global warming
.
The concept of Growing-degree day contributes to our understanding of phenology.
The North American Bird Phenology Program
at USGS Patuxent Wildlife Research Center (PWRC) is in possession of a collection of millions of bird arrival and departure date records for over 870 species across North America, dating between 1880 and 1970. This program, originally started by Wells W. Cooke, involved over 3,000 observers including many notable naturalists of the time. The program ran for 90 years and came to a close in 1970 when other programs starting up at PWRC took precedent. The program was again started in 2009 to digitize the collection of records and now with the help of citizens worldwide, each record is being transcribed into a database which will be publicly accessible for use.
Gilbert White
and William Markwick reported the seasonal events of more than 400 plant and animal species, Gilbert White in Selbourne, Hampshire and William Markwick in Battle, Sussex over a 25-year period between 1768 and 1793. The data, reported in White's Natural History and Antiquities of Selborne are reported as the earliest and latest dates for each event over 25 years; so annual changes cannot therefore be determined.
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. Such historical records may, in principle, be capable of providing estimates of climate at dates before instrumental records became available. For example, records of the harvest dates of the pinot noir
grape
in Burgundy have been used in an attempt to reconstruct spring–summer temperatures from 1370 to 2003; the reconstructed values during 1787–2000 have a correlation with Paris instrumental data of about 0.75.
is the founding father of modern phenological recording. Marsham was a wealthy landowner who kept systematic records of "Indications of spring" on his estate at Stratton Strawless
, Norfolk
, from 1736. These were in the form of dates of the first occurrence of events such as flowering, bud burst, emergence or flight of an insect. Consistent records of the same events or "phenophases" were maintained by generations of the same family over unprecedentedly long periods of time, eventually ending with the death of Mary Marsham in 1958, so that trends can be observed and related to long-term climate records. The data show significant variation in dates which broadly correspond with warm and cold years. 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.
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 of the order of 1.5°C in the same period.
Towards the end of the 19th century the recording of the appearance and development of plants and animals became a national pastime, and between 1891 and 1948 a programme of phenological recording was organised across the British Isles by the Royal Meteorological Society
(RMS). Up to 600 observers submitted returns in some years, with numbers averaging a few hundred. During this period 11 main plant phenophases were consistently recorded over the 58 years 1891-1948, and a further 14 phenophases were recorded for 20 years between 1929 and 1948. The returns were summarised each year in the Quarterly Journal of the RMS as The Phenological Reports. The 58-year data have been summarised by Jeffree (1960), and show that flowering dates could be as many as 21 days early and as many as 34 days late, with extreme earliness greatest in summer flowering species, and extreme lateness in spring flowering species. In all 25 species the timings of all phenological events are significantly related to temperature indicating that phenological events are likely to get earlier as climate warms.
The Phenological Reports ended suddenly in 1948 after 58 years, and Britain was without a national recording scheme for almost 50 years, just at a time when climate change was becoming evident. During this period, important contributions were made by individual dedicated observers. The naturalist and author Richard Fitter recorded the First Flowering Date (FFD) of 557 species British flowering plants in Oxfordshire between about 1954 and 1990. Writing in Science
in 2002, Richard Fitter and his son Alistair Fitter found that "the average FFD of 385 British plant species has advanced by 4.5 days during the past decade compared with the previous four decades." They note that FFD is sensitive to temperature, as is generally agreed, that "150 to 200 species may be flowering on average 15 days earlier in Britain now than in the very recent past" and that these earlier FFDs will have "profound ecosystem and evolutionary consequences".
In the last decade, national recording in Britain has been resumed by the UK Phenology network http://www.naturescalendar.org.uk, run by Woodland Trust
and the Centre for Ecology and Hydrology
and the BBC Springwatch survey. There is a USA National Phenology Network http://www.usanpn.org/ in which both professional scientists and lay recorders participate, a European Phenology Network that has monitoring, research and educational remits and many other countries such as Canada (Alberta Plantwatch http://plantwatch.fanweb.ca/ and Saskatchewan PlantWatch), China and Australia have phenological programs.
In eastern North America, almanacs are traditionally used for information on action phenology (in agriculture), taking into account the astronomical positions at the time.
William Felker has studied phenology in Ohio
, USA since 1973 and now publishes "Poor Will's Almanack", a phenological almanac for farmers (not to be confused with a late 18th century almanac by the same name).
s and stands of vegetation
on a global scale using proxy approaches. These methods complement the traditional phenological methods which recorded the first occurrences of individual species and phenophases.
The most successful of these approaches is based on tracking the temporal change of a Vegetation Index (like Normalized Difference Vegetation Index
(NDVI)). NDVI makes use of the vegetation's typical low reflection in the red (red energy is mostly absorbed by growing plants for Photosynthesis) and strong reflection in the Near Infrared
(Infrared energy is mostly reflected by plants due to their cellular structure). Due to its robustness and simplicity, NDVI has become one of the most popular remote sensing based products. Typically, a vegetation index is constructed in such a way that the attenuated reflected sunlight energy (1% to 30% of incident sunlight) is amplified by ratio-ing red and NIR following this equation:
The evolution of the vegetation index through time, depicted by the graph above, exhibits a strong correlation
with the typical green vegetation growth stages (emergence, vigor/growth, maturity, and harvest/senescence). These temporal curves are analyzed to extract useful parameters about the vegetation growing season (start of season, end of season, length of growing season
, etc.). Other growing season parameter
s could potentially be extracted, and global maps of any of these growing season parameters could then be constructed and used in all sorts of climatic change
studies.
A noteworthy example of the use of remote sensing
based phenology is the work of Ranga Myneni from Boston University
. This work showed an apparent increase in vegetation productivity that most likely resulted from the increase in temperature and lengthening of the growing season in the boreal forest. Another example based on the MODIS
enhanced vegetation index (EVI
) reported by Alfredo Huete at the University of Arizona and colleagues showed that the Amazon Rainforest
, as opposed to the long held view of a monotonous growing season or growth only during the wet rainy season, does in fact exhibit growth spurts during the dry season.,.
However, these phenological parameters are only an approximation of the true biological growth stages. This is mainly due to the limitation of current space based remote sensing, especially the spatial resolution, and the nature of vegetation index. A pixel in an image does not contain a pure target (like a tree, a shrub, etc.) but contains a mixture of whatever intersected the sensor's field of view.
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
φαίνω (phainō), "to show, to bring to light, make to appear" + λόγος (logos
Logos
' is an important term in philosophy, psychology, rhetoric and religion. Originally a word meaning "a ground", "a plea", "an opinion", "an expectation", "word," "speech," "account," "reason," it became a technical term in philosophy, beginning with Heraclitus ' is an important term in...
), amongst others "study, discourse, reasoning" and indicates that phenology has been principally concerned with the dates of first occurrence of biological events in their annual cycle. Examples include the date of emergence of leaves and flowers, the first flight of butterflies and the first appearance of migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
birds, the date of leaf colouring and fall in deciduous trees, the dates of egg-laying of birds and amphibia, or the timing of the developmental cycles of temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
-zone honey bee colonies. In the scientific literature on ecology
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
, the term is used more generally to indicate the time frame for any seasonal biological phenomena, including the dates of last appearance (e.g., the seasonal phenology of a species may be from April through September).
Because many such phenomena are very sensitive to small variations in climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
, especially to temperature, phenological records can be a useful proxy
Proxy (climate)
In the study of past climates is known as paleoclimatology, climate proxies are preserved physical characteristics of the past that stand in for direct measurements , to enable scientists to reconstruct the climatic conditions that prevailed during much of the Earth's history...
for temperature in historical climatology
Historical climatology
Historical climatology is the study of historical changes in climate and their effect on human history and development. This differs from paleoclimatology which encompasses climate change over the entire history of the earth. The study seeks to define periods in human history where temperature or...
, especially in the study of climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
and global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
. For example, viticultural records of grape harvests in Europe have been used to reconstruct a record of summer growing season temperatures going back more than 500 years.
In addition to providing a longer historical baseline than instrumental measurements, phenological observations provide high temporal resolution
Temporal resolution
Temporal resolution refers to the precision of a measurement with respect to time. Often there is a tradeoff between temporal resolution of a measurement and its spatial resolution. This trade-off can be attributed to the finite speed of light and the fact that it takes a certain period of time...
of ongoing changes related to global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
.
The concept of Growing-degree day contributes to our understanding of phenology.
Past records
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. If ash before oak, you're in for a soak". But the indications can be pretty unreliable, as an alternative version of the rhyme shows: "If the oak is out before the ash, 'Twill be a summer of wet and splash; If the ash is out before the oak,'Twill be a summer of fire and smoke." Theoretically, though, these are not mutually exclusive, as one forecasts immediate conditions and one forecasts future conditions.The North American Bird Phenology Program
North American Bird Phenology Program
The North American Bird Phenology Program houses a unique and largely forgotten collection of six million Migration Observer Cards that illuminate migration patterns and population status of the birds of North America. These handwritten cards contain almost all of what was known of bird...
at USGS Patuxent Wildlife Research Center (PWRC) is in possession of a collection of millions of bird arrival and departure date records for over 870 species across North America, dating between 1880 and 1970. This program, originally started by Wells W. Cooke, involved over 3,000 observers including many notable naturalists of the time. The program ran for 90 years and came to a close in 1970 when other programs starting up at PWRC took precedent. The program was again started in 2009 to digitize the collection of records and now with the help of citizens worldwide, each record is being transcribed into a database which will be publicly accessible for use.
Gilbert White
Gilbert White
Gilbert White FRS was a pioneering English naturalist and ornithologist.-Life:White was born in his grandfather's vicarage at Selborne in Hampshire. He was educated at the Holy Ghost School and by a private tutor in Basingstoke before going to Oriel College, Oxford...
and William Markwick reported the seasonal events of more than 400 plant and animal species, Gilbert White in Selbourne, Hampshire and William Markwick in Battle, Sussex over a 25-year period between 1768 and 1793. The data, reported in White's Natural History and Antiquities of Selborne are reported as the earliest and latest dates for each event over 25 years; so annual changes cannot therefore be determined.
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. Such historical records may, in principle, be capable of providing estimates of climate at dates before instrumental records became available. For example, records of the harvest dates of the pinot noir
Pinot Noir
Pinot noir is a black wine grape variety of the species Vitis vinifera. The name may also refer to wines created predominantly from Pinot noir grapes...
grape
Grape
A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...
in Burgundy have been used in an attempt to reconstruct spring–summer temperatures from 1370 to 2003; the reconstructed values during 1787–2000 have a correlation with Paris instrumental data of about 0.75.
Modern records
Robert MarshamRobert Marsham
Robert Marsham was an English naturalist considered to be the founding father of phenology, the study of the effects of the seasons on plants and animals....
is the founding father of modern phenological recording. Marsham was a wealthy landowner who kept systematic records of "Indications of spring" on his estate at Stratton Strawless
Stratton Strawless
Stratton Strawless is a village in the county of Norfolk and district of Broadland. The civil parish covers and has a population of 495. Located close and to the east of the A140 road and being south of the market town of Aylsham and some north of Norwich...
, Norfolk
Norfolk
Norfolk is a low-lying county in the East of England. It has borders with Lincolnshire to the west, Cambridgeshire to the west and southwest and Suffolk to the south. Its northern and eastern boundaries are the North Sea coast and to the north-west the county is bordered by The Wash. The county...
, from 1736. These were in the form of dates of the first occurrence of events such as flowering, bud burst, emergence or flight of an insect. Consistent records of the same events or "phenophases" were maintained by generations of the same family over unprecedentedly long periods of time, eventually ending with the death of Mary Marsham in 1958, so that trends can be observed and related to long-term climate records. The data show significant variation in dates which broadly correspond with warm and cold years. 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.
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 of the order of 1.5°C in the same period.
Towards the end of the 19th century the recording of the appearance and development of plants and animals became a national pastime, and between 1891 and 1948 a programme of phenological recording was organised across the British Isles by the Royal Meteorological Society
Royal Meteorological Society
The Royal Meteorological Society traces its origins back to 3 April 1850 when the British Meteorological Society was formed as a society the objects of which should be the advancement and extension of meteorological science by determining the laws of climate and of meteorological phenomena in general...
(RMS). Up to 600 observers submitted returns in some years, with numbers averaging a few hundred. During this period 11 main plant phenophases were consistently recorded over the 58 years 1891-1948, and a further 14 phenophases were recorded for 20 years between 1929 and 1948. The returns were summarised each year in the Quarterly Journal of the RMS as The Phenological Reports. The 58-year data have been summarised by Jeffree (1960), and show that flowering dates could be as many as 21 days early and as many as 34 days late, with extreme earliness greatest in summer flowering species, and extreme lateness in spring flowering species. In all 25 species the timings of all phenological events are significantly related to temperature indicating that phenological events are likely to get earlier as climate warms.
The Phenological Reports ended suddenly in 1948 after 58 years, and Britain was without a national recording scheme for almost 50 years, just at a time when climate change was becoming evident. During this period, important contributions were made by individual dedicated observers. The naturalist and author Richard Fitter recorded the First Flowering Date (FFD) of 557 species British flowering plants in Oxfordshire between about 1954 and 1990. Writing in Science
Science (journal)
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....
in 2002, Richard Fitter and his son Alistair Fitter found that "the average FFD of 385 British plant species has advanced by 4.5 days during the past decade compared with the previous four decades." They note that FFD is sensitive to temperature, as is generally agreed, that "150 to 200 species may be flowering on average 15 days earlier in Britain now than in the very recent past" and that these earlier FFDs will have "profound ecosystem and evolutionary consequences".
In the last decade, national recording in Britain has been resumed by the UK Phenology network http://www.naturescalendar.org.uk, run by Woodland Trust
Woodland Trust
The Woodland Trust is a conservation charity in the United Kingdom concerned with the protection and sympathetic management of native woodland heritage.-History:...
and the Centre for Ecology and Hydrology
Centre for Ecology and Hydrology
The Centre for Ecology & Hydrology is the United Kingdom's Centre of Excellence for integrated research in hydrology, terrestrial and freshwater ecosystems and their interaction with the atmosphere...
and the BBC Springwatch survey. There is a USA National Phenology Network http://www.usanpn.org/ in which both professional scientists and lay recorders participate, a European Phenology Network that has monitoring, research and educational remits and many other countries such as Canada (Alberta Plantwatch http://plantwatch.fanweb.ca/ and Saskatchewan PlantWatch), China and Australia have phenological programs.
In eastern North America, almanacs are traditionally used for information on action phenology (in agriculture), taking into account the astronomical positions at the time.
William Felker has studied phenology in Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
, USA since 1973 and now publishes "Poor Will's Almanack", a phenological almanac for farmers (not to be confused with a late 18th century almanac by the same name).
Airborne sensors
Recent technological advances in studying the earth from space have resulted in a new field of phenological research that is concerned with observing the phenology of whole ecosystemEcosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
s and stands of vegetation
Vegetation
Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader...
on a global scale using proxy approaches. These methods complement the traditional phenological methods which recorded the first occurrences of individual species and phenophases.
The most successful of these approaches is based on tracking the temporal change of a Vegetation Index (like Normalized Difference Vegetation Index
Normalized Difference Vegetation Index
The Normalized Difference Vegetation Index is a simple graphical indicator that can be used to analyze remote sensing measurements, typically but not necessarily from a space platform, and assess whether the target being observed contains live green vegetation or not.-Brief history:The exploration...
(NDVI)). NDVI makes use of the vegetation's typical low reflection in the red (red energy is mostly absorbed by growing plants for Photosynthesis) and strong reflection in the Near Infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
(Infrared energy is mostly reflected by plants due to their cellular structure). Due to its robustness and simplicity, NDVI has become one of the most popular remote sensing based products. Typically, a vegetation index is constructed in such a way that the attenuated reflected sunlight energy (1% to 30% of incident sunlight) is amplified by ratio-ing red and NIR following this equation:
Correlation
In statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation refers to any of a broad class of statistical relationships involving dependence....
with the typical green vegetation growth stages (emergence, vigor/growth, maturity, and harvest/senescence). These temporal curves are analyzed to extract useful parameters about the vegetation growing season (start of season, end of season, length of growing season
Growing season
In botany, horticulture, and agriculture the growing season is the period of each year when native plants and ornamental plants grow; and when crops can be grown....
, etc.). Other growing season parameter
Parameter
Parameter from Ancient Greek παρά also “para” meaning “beside, subsidiary” and μέτρον also “metron” meaning “measure”, can be interpreted in mathematics, logic, linguistics, environmental science and other disciplines....
s could potentially be extracted, and global maps of any of these growing season parameters could then be constructed and used in all sorts of climatic change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
studies.
A noteworthy example of the use of remote sensing
Remote sensing
Remote sensing is the acquisition of information about an object or phenomenon, without making physical contact with the object. In modern usage, the term generally refers to the use of aerial sensor technologies to detect and classify objects on Earth by means of propagated signals Remote sensing...
based phenology is the work of Ranga Myneni from Boston University
Boston University
Boston University is a private research university located in Boston, Massachusetts. With more than 4,000 faculty members and more than 31,000 students, Boston University is one of the largest private universities in the United States and one of Boston's largest employers...
. This work showed an apparent increase in vegetation productivity that most likely resulted from the increase in temperature and lengthening of the growing season in the boreal forest. Another example based on the MODIS
MODIS
The Moderate-resolution Imaging Spectroradiometer is a payload scientific instrument launched into Earth orbit by NASA in 1999 on board the Terra Satellite, and in 2002 on board the Aqua satellite...
enhanced vegetation index (EVI
EVI
The enhanced vegetation index is an 'optimized' index designed to enhance the vegetation signal with improved sensitivity in high biomass regions and improved vegetation monitoring through a de-coupling of the canopy background signal and a reduction in atmosphere influences...
) reported by Alfredo Huete at the University of Arizona and colleagues showed that the Amazon Rainforest
Amazon Rainforest
The Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...
, as opposed to the long held view of a monotonous growing season or growth only during the wet rainy season, does in fact exhibit growth spurts during the dry season.,.
However, these phenological parameters are only an approximation of the true biological growth stages. This is mainly due to the limitation of current space based remote sensing, especially the spatial resolution, and the nature of vegetation index. A pixel in an image does not contain a pure target (like a tree, a shrub, etc.) but contains a mixture of whatever intersected the sensor's field of view.
See also
- Citizen scienceCitizen scienceCitizen science is a term used for the systematic collection and analysis of data; development of technology; testing of natural phenomena; and the dissemination of these activities by researchers on a primarily avocational basis...
- Nature DetectivesNature DetectivesNature Detectives is an online phenology research and education project for 4-18 year-olds in the UK. It is run by the Woodland Trust, as part of the UK Phenology Network....
- Season creepSeason creepIn phenology, season creep is a neologism that refers to observed changes in the timing of the seasons,especially earlier indications of spring widely observed in temperate areas across the Northern Hemisphere....
- Growing-degree day
External links
- North American Bird Phenology Program Citizen science program to digitize bird phenology records
- Project Budburst Citizen Science for Plant Phenology in the USA
- USA National Phenology Network Citizen science and research network observations on phenology in the USA
- AMC's Mountain Watch Citizen science and phenology monitoring in the Appalachian mountains
- UK Nature's Calendar UK Phenology network.
- Nature's Calendar Ireland Spring Watch & Autumn Watch.
- Naturewatch: A Canadian Phenology project.
- Spring Alive Project Phenological survey on birds for children.
- Moj Popek Citizen Science for Plant Phenology in Slovenia.
- Observatoire des Saisons French Phenology network.