Plant ecology

Plant ecology is a subdiscipline of ecology which studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, and the interactions among and between plants and other organisms.[1] Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, and competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands.

A global overview of the Earth's major vegetation types is provided by O.W. Archibold.[2] He recognizes 11 major vegetation types: tropical forests, tropical savannas, arid regions (deserts), Mediterranean ecosystems, temperate forest ecosystems, temperate grasslands, coniferous forests, tundra (both polar and high mountain), terrestrial wetlands, freshwater ecosystems and coastal/marine systems. This breadth of topics shows the complexity of plant ecology, since it includes plants from floating single-celled algae up to large canopy forming trees.

One feature that defines plants is photosynthesis. Photosynthesis is the process of a chemical reactions to create glucose and oxygen, which is vital for plant life.[3] One of the most important aspects of plant ecology is the role plants have played in creating the oxygenated atmosphere of earth, an event that occurred some 2 billion years ago. It can be dated by the deposition of banded iron formations, distinctive sedimentary rocks with large amounts of iron oxide. At the same time, plants began removing carbon dioxide from the atmosphere, thereby initiating the process of controlling Earth's climate. A long term trend of the Earth has been toward increasing oxygen and decreasing carbon dioxide, and many other events in the Earth's history, like the first movement of life onto land, are likely tied to this sequence of events.[1]

One of the early classic books on plant ecology was written by J.E. Weaver and F.E. Clements.[4] It talks broadly about plant communities, and particularly the importance of forces like competition and processes like succession.The term ecology was coined by German biologist Ernst Hackel and term related to the study of animals in relation to both physical environment and other plants and animals with which they interacted.

Plant ecology can also be divided by levels of organization including plant ecophysiology, plant population ecology, community ecology, ecosystem ecology, landscape ecology and biosphere ecology.[1][5]

The study of plants and vegetation is complicated by their form. First, most plants are rooted in the soil, which makes it difficult to observe and measure nutrient uptake and species interactions. Second, plants often reproduce vegetatively, that is asexually, in a way that makes it difficult to distinguish individual plants. Indeed, the very concept of an individual is doubtful, since even a tree may be regarded as a large collection of linked meristems.[6] Hence, plant ecology and animal ecology have different styles of approach to problems that involve processes like reproduction, dispersal and mutualism. Some plant ecologists have placed considerable emphasis upon trying to treat plant populations as if they were animal populations, focusing on population ecology.[7] Many other ecologists believe that while it is useful to draw upon population ecology to solve certain scientific problems, plants demand that ecologists work with multiple perspectives, appropriate to the problem, the scale and the situation.[1]

Diego Garcia Mixed Species Marsh
A tropical plant community on Diego Garcia
Rangeland monitoring using Parker 3-step Method, Okanagan Washington 2002 (2)
Rangeland monitoring using Parker 3-step Method, Okanagan Washington 2002

History

AvHumboldt
Alexander von Humboldt's work connecting plant distributions with environmental factors played an important role in the genesis of the discipline of plant ecology.

Plant ecology has its origin in the application of plant physiology to the questions raised by plant geographers.[8][9]:13–16 Carl Ludwig Willdenow was one of the first to note that similar climates produced similar types of vegetation, even when they were located in different parts of the world. Willdenow's student, Alexander von Humboldt, used physiognomy to describe vegetation types and observed that the distribution vegetation types was based on environmental factors. Later plant geographers who built upon Humboldt's work included Joakim Frederik Schouw, A.P. de Candolle, August Grisebach and Anton Kerner von Marilaun. Schouw's work, published in 1822, linked plant distributions to environmental factors (especially temperature) and established the practice of naming plant associations by adding the suffix -etum to the name of the dominant species. Working from herbarium collections, De Candolle searched for general rules of plant distribution and settled on using temperature as well.[9]:14–16 Grisebach's two-volume work, Die Vegetation der Erde nach Ihrer Klimatischen Anordnung, published in 1872, saw plant geography reach its "ultimate form" as a descriptive field.[8]:29

Starting in the 1870s, Swiss botanist Simon Schwendener, together with his students and colleagues, established the link between plant morphology and physiological adaptations, laying the groundwork for the first ecology textbooks, Eugenius Warming's Plantesamfund (published in 1895) and Andreas Schimper's 1898 Pflanzengeographie auf Physiologischer Grundlage.[8] Warming successfully incorporated plant morphology, physiology taxonomy and biogeography into plant geography to create the field of plant ecology. Although more morphological than physiological, Schimper's has been considered the beginning of plant physiological ecology.[9]:17–18 Plant ecology was initially built around static ideas of plant distribution; incorporating the concept of succession added an element to change through time to the field. Henry Chandler Cowles' studies of plant succession on the Lake Michigan sand dunes (published in 1899) and Frederic Clements' 1916 monograph on the subject established it as a key element of plant ecology.[8]

Plant ecology developed within the wider discipline of ecology over the twentieth century. Inspired by Warming's Plantesamfund, Arthur Tansley set out to map British plant communities. In 1904 he teamed up with William Gardner Smith and others involved in vegetation mapping to establish the Central Committee for the Survey and Study of British Vegetation, later shortened to British Vegetation Committee. In 1913, the British Vegetation Committee organised the British Ecological Society (BES), the first professional society of ecologists.[10] This was followed in 1917 by the establishment of the Ecological Society of America (ESA); plant ecologists formed the largest subgroup among the inaugural members of the ESA.[8]:41

Cowles' students played an important role in the development of the field of plant ecology during the first half of the twentieth century, among them William S. Cooper, E. Lucy Braun and Edgar Transeau.[9]:23

Distribution

Biomes
World biomes are based upon the type of dominant plant.

Plant distributions is governed by a combination of historical factors, ecophysiology and biotic interactions. The set of species that can be present at a given site is limited by historical contingency. In order to show up, a species must either have evolved in an area or dispersed there (either naturally or through human agency), and must not have gone locally extinct. The set of species present locally is further limited to those that possess the physiological adaptations to survive the environmental conditions that exist. This group is further shaped through interactions with other species.[11]:2–3

Plant communities are broadly distributed into biomes based on the form of the dominant plant species. For example, grasslands are dominated by grasses, while forests are dominated by trees. Biomes are determined by regional climates, mostly temperature and precipitation, and follow general latitudinal trends. Within biomes, there may be many ecological communities, which are impacted not only by climate and a variety of smaller-scale features, including soils, hydrology, and disturbance regime. Biomes also change with elevation, high elevations often resembling those found at higher latitudes.

Biological interactions

Competition

Plants, like most life forms, require relatively few basic elements: carbon, hydrogen, oxygen, nitrogen, phosphorus and sulphur; hence they are known as CHNOPS life forms. There are also lesser elements needed as well, frequently termed micronutrients, such as magnesium and sodium. When plants grow in close proximity, they may deplete supplies of these elements and have a negative impact upon neighbours. Competition for resources vary from complete symmetric (all individuals receive the same amount of resources, irrespective of their size) to perfectly size symmetric (all individuals exploit the same amount of resource per unit biomass) to absolutely size-asymmetric (the largest individuals exploit all the available resource). The degree of size asymmetry has major effects on the structure and diversity of ecological communities.In many cases (perhaps most) the negative effects upon neighbours arise from size asymmetric competition for light. In other cases, there may be competition below ground for water, nitrogen, or phosphorus. To detect and measure competition, experiments are necessary; these experiments require removing neighbours, and measuring responses in the remaining plants.[12] Many such studies are required before useful generalizations can be drawn.

Overall, it appears that light is the most important resource for which plants compete, and the increase in plant height over evolutionary time likely reflects selection for taller plants to better intercept light. Many plant communities are therefore organized into hierarchies based upon the relative competitive abilities for light.[12] In some systems, particularly infertile or arid systems, below ground competition may be more significant.[13] Along natural gradients of soil fertility, it is likely that the ratio of above ground to below ground competition changes, with higher above ground competition in the more fertile soils.[14][15] Plants that are relatively weak competitors may escape in time (by surviving as buried seeds) or in space (by dispersing to a new location away from strong competitors.)

In principle, it is possible to examine competition at the level of the limiting resources if a detailed knowledge of the physiological processes of the competing plants is available. However, in most terrestrial ecological studies, there is only little information on the uptake and dynamics of the resources that limit the growth of different plant species, and, instead, competition is inferred from observed negative effects of neighbouring plants without knowing precisely which resources the plants were competing for. In certain situations, plants may compete for a single growth-limiting resource, perhaps for light in agricultural systems with sufficient water and nutrients, or in dense stands of marsh vegetation, but in many natural ecosystems plants may be colimited by several resources, e.g. light, phosphorus and nitrogen at the same time.[16]

Therefore, there are many details that remain to be uncovered, particularly the kinds of competition that arise in natural plant communities, the specific resource(s), the relative importance of different resources, and the role of other factors like stress or disturbance in regulating the importance of competition.[1][17]

Mutualism

Mutualism is defined as an interaction "between two species or individuals that is beneficial to both". Probably the most widespread example in plants is the mutual beneficial relationship between plants and fungi, known as mycorrhizae. The plant is assisted with nutrient uptake, while the fungus receives carbohydrates. Some the earliest known fossil plants even have fossil mycorrhizae on their rhizomes.[1]

The flowering plants are a group that have evolved by using two major mutualisms. First, flowers are pollinated by insects. This relationship seems to have its origins in beetles feeding on primitive flowers, eating pollen and also acting (unwittingly) as pollinators. Second, fruits are eaten by animals, and the animals then disperse the seeds. Thus, the flowering plants actually have three major types of mutualism, since most higher plants also have mycorrhizae.[1]

Plants may also have beneficial effects upon one another, but this is less common. Examples might include "nurse plants" whose shade allows young cacti to establish. Most examples of mutualism, however, are largely beneficial to only one of the partners, and may not really be true mutualism. The term used for these more one-sided relationships, which are mostly beneficial to one participant, is facilitation. Facilitation among neighboring plants may act by reducing the negative impacts of a stressful environment.[18] In general, facilitation is more likely to occur in physically stressful environments than in favorable environments, where competition may be the most important interaction among species.[19]

Commensalism is similar to facilitation, in that one plant is mostly exploiting another. A familiar example is the ephiphytes which grow on branches of tropical trees, or even mosses which grow on trees in deciduous forests.

It is important to keep track of the benefits received by each species to determine the appropriate term. Although people are often fascinated by unusual examples, it is important to remember that in plants, the main mutualisms are mycorrhizae, pollination, and seed dispersal.[1]

Herbivory

Grazing exclosure Abisko
Reindeer in front of herbivore exclosures. Excluding different herbivores (here reindeer, or reindeer and rodents) has different effects on the vegetation.

An important ecological function of plants is that they produce organic compounds for herbivores[20] in the bottom of the food web. A large number of plant traits, from thorns to chemical defenses, can be related to the intensity of herbivory. Large herbivores can also have many effects on vegetation. These include removing selected species, creating gaps for regeneration of new individuals, recycling nutrients, and dispersing seeds. Certain ecosystem types, such as grasslands, may be dominated by the effects of large herbivores, although fire is also an equally important factor in this biome. In few cases, herbivores are capable of nearly removing all the vegetation at a site (for example, geese in the Hudson Bay Lowlands of Canada, and nutria in the marshes of Louisiana[21]) but normally herbivores have a more selective impact, particularly when large predators control the abundance of herbivores. The usual method of studying the effects of herbivores is to build exclosures, where they cannot feed, and compare the plant communities in the exclosures to those outside over many years. Often such long term experiments show that herbivores have a significant effect upon the species that make up the plant community.[1]

Other topics

Abundance

The ecological success of a plant species in a specific environment may be quantified by its abundance, and depending on the life form of the plant different measures of abundance may be relevant, e.g. density, biomass, or plant cover.

The change in the abundance of a plant species may be due to both abiotic factors, e.g. climate change, or biotic factors, e.g. herbivory or interspecific competition.

Colonisation and local extinction

Whether a plant species is present at a local area depends on the processes of colonisation and local extinction. The probability of colonisation decreases with distance to neighboring habitats where the species is present and increases with plant abundance and fecundity in neighboring habitats and the dispersal distance of the species. The probability of local extinction decreases with abundance (both living plants and seeds in the soil seed bank).

Reproduction

There are a few ways that reproduction occurs within plant life, and one way is through parthenogenesis. Parthenogenesis is defined as "a form of asexual reproduction in which genetically identical offspring (clones) are produced".[22] Another form of reproduction is through cross-fertilization, which is defined as "fertilization in which the egg and sperm are produced by different individuals", and in plants this occurs in the ovule. Once an ovule is fertilized within the plant this becomes what is known as a seed. A seed normally contains the nutritive tissue also known as the endosperm and the embryo. A seedling is a young plant that has recently gone through germination. [23] Another form of reproduction of a plant is self-fertilization; in which both the sperm and the egg are produced from the same individual- this plant is therefore a self-compatible titled plant.[24]

See also

References

  1. ^ a b c d e f g h i Keddy, Paul A. (2007). Plants and Vegetation. Cambridge: Cambridge University Press. ISBN 978-0-521-86480-0.
  2. ^ Archibold, O.W. (1995). Ecology of World Vegetation. London.: Chapman and Hall. pp. 510 p. ISBN 0-412-44290-6.
  3. ^ Carroll & Salt. Ecology for Gardeners. Timber Press, Inc. pp. Glossary, page 287. ISBN 0-88192-611-6.
  4. ^ Weaver, J. E. and F. E. Clements. 1938. Plant Ecology. 2nd edn. New York: McGraw-Hill Book Company.
  5. ^ Schulze, Ernst-Detlef; et al. (2005). Plant Ecology. Springer. Retrieved April 24, 2012. ISBN 3-540-20833-X
  6. ^ Williams, G. C. 1975. Sex and Evolution. Monographs in Population Biology. No. 8. Princeton: Princeton University Press.
  7. ^ Harper, J. L. 1977. Population Biology of Plants. London: Academic Press.
  8. ^ a b c d e van der Valk, Arnold (2011). "Origins and Development of Ecology". In Kevin deLaplante; Bryson Brown; Kent A. Peacock (eds.). Philosophy of Ecology. Handbook of the Philosophy of Science. 11. Amsterdam: Elsevier. pp. 25–48.
  9. ^ a b c d Barbour, Michael G.; Jack H. Burk; Wanna D. Pitts; Frank S. Gilliam; Mark W. Schwartz (1999). Terrestrial Plant Ecology (Third ed.). Addison Wesley Longman.
  10. ^ Cooper, W. S. (1957). "Sir Arthur Tansley and the Science of Ecology". Ecology. 38 (4): 658–659. doi:10.2307/1943136.
  11. ^ Lambers, Hans; F. Stuart Chapin III; Thijs L. Pons (2008). Plant Physiological Ecology (Second ed.).
  12. ^ a b Keddy, Paul A. (2001). Competition. Dordrecht: Kluwer. p. 552. ISBN 0-7923-6064-8.
  13. ^ Capser, Brenda B. and Robert. B. Jackson. 1997. Plant competition underground. Annual Review of Ecology and Systematics 28: 545–570.
  14. ^ Belcher, J., P.A. Keddy, and L. Twolan-Strutt. 1995. Root and shoot competition along a soil depth gradient. Journal of Ecology 83: 673–682
  15. ^ Twolan-Strutt, L. and P.A. Keddy. 1996. Above- and below-ground competition intensity in two contrasting wetland plant communities. Ecology 77: 259–270.
  16. ^ Craine, J. M. (2009). Resource strategies in wild plants. Princeton University Press, Princeton.
  17. ^ Grime, J. P. 1979. Plant Strategies and Vegetation Processes. Chichester: John Wiley.
  18. ^ Callaway, R. M. 1995. Positive interactions among plants (Interpreting botanical progress). The Botanical Review 61: 306–349.
  19. ^ Keddy, Paul A., Competition, 2nd ed. (2001), Kluwer, Dordrecht. 552 p.
  20. ^ Schulze, Ernst-Detlef; et al. (2005). Plant Ecology – (Section 1.10.1: Herbivory). Springer. Retrieved April 24, 2012. ISBN 3-540-20833-X
  21. ^ Keddy, P.A., Wetland Ecology: Principles and Conservation, 2nd ed. (2010), Cambridge University Press, Cambridge, UK. 497 p. Chapt. 6. Herbivory.
  22. ^ Carrol & Salt. Ecology for Gardeners. Timber Press, Inc. p. 286. ISBN 0-88192-611-6.
  23. ^ Carroll & Salt. Ecology for Gardeners. Timber Press, Inc. p. 282. ISBN 0-88192-611-6.
  24. ^ Carroll & Salt. Ecology for Gardeners. Timber Press, Inc. p. 288. ISBN 0-88192-611-6.

Further reading

  • Archibold, O.W. (1995). "Ecology of World Vegetation". Chapman and Hall, London. Missing or empty |url= (help)
  • Cittadino, E. (1990). Nature as the Laboratory. Darwinian Plant Ecology in the German Empire, 1880-1900. Cambridge: Cambridge University Press.
  • Crawley, Michael J. (1997) [1986]. Plant Ecology. Blackwell Scientific Publications. Retrieved April 24, 2012. ISBN 0-632-01363-X
  • Gibson, J. Phil; Gibson, Terri R. (2006). "Plant Ecology". Green World. Retrieved April 24, 2012. ISBN 0-7910-8566-X
  • Keddy, Paul A. (2007). "Plants and Vegetation: Origins, Processes, Consequences". Cambridge University Press. Missing or empty |url= (help) ISBN 978-0-521-86480-0
Annual plant

An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical location, and may not correspond to the four traditional seasonal divisions of the year. With respect to the traditional seasons annual plants are generally categorized into summer annuals and winter annuals. Summer annuals germinate during spring or early summer and mature by autumn of the same year. Winter annuals germinate during the autumn and mature during the spring or summer of the following calendar year.One seed-to-seed life cycle for an annual can occur in as little as a month in some species, though most last several months. Oilseed rapa can go from seed-to-seed in about five weeks under a bank of fluorescent lamps. This style of growing is often used in classrooms for education. Many desert annuals are therophytes, because their seed-to-seed life cycle is only weeks and they spend most of the year as seeds to survive dry conditions.

Biennial plant

A biennial plant is a flowering plant that takes two years to complete its biological lifecycle. In the first year, the plant grows leaves, stems, and roots (vegetative structures), then it enters a period of dormancy over the colder months. Usually the stem remains very short and the leaves are low to the ground, forming a rosette. Many biennials require a cold treatment, or vernalization, before they will flower. During the next spring or summer, the stem of the biennial plant elongates greatly, or "bolts". The plant then flowers, producing fruits and seeds before it finally dies. There are far fewer biennials than either perennial plants or annual plants.

Under extreme climatic conditions, a biennial plant may complete its life cycle rapidly (e.g., in three months instead of two years). This is quite common in vegetable or flower seedlings that were vernalized before they were planted in the ground. This behavior leads to many normally biennial plants being treated as annuals in some areas. Conversely, an annual grown under extremely favorable conditions may have highly successful seed propagation, giving it the appearance of being biennial or perennial. Some short-lived perennials may appear to be biennial rather than perennial. True biennials flower only once, while many perennials will flower every year once mature.

From a gardener's perspective, a plant's status as annual, biennial, or perennial often varies based on location or purpose. Biennials grown for flowers, fruits, or seeds need to be grown for two years. Biennials that are grown for edible leaves or roots are grown for just one year (and not grown on a second year to run to seed).

Examples of biennial plants are members of the onion family including leek, some members of the cabbage family, common mullein, parsley, fennel, Lunaria, silverbeet, Black-eyed Susan, Sweet William, colic weed, carrot, and some hollyhocks. Plant breeders have produced annual cultivars of several biennials that will flower the first year from seed, for example, foxglove and stock.

Botanical Society of Scotland

The Botanical Society of Scotland (BSS) is the national learned society for botanists of Scotland. The Society's aims are to advance knowledge and appreciation of flowering and cryptogamic plants, algae and fungi. The Society's activities include lectures (mainly held in Edinburgh, but also in other Scottish cities), symposia, field excursions, field projects and an annual exhibition meeting, held jointly with the Botanical Society of Britain and Ireland for exchange of information between botanists working in different areas. Its publications include a twice-yearly newsletter, BSS News, and a scientific journal, Plant Ecology & Diversity. The society is closely linked to the Royal Botanic Garden Edinburgh and the Scottish universities.

Ecology of Banksia

The ecology of Banksia refers to all the relationships and interactions among the plant genus Banksia and its environment. Banksia has a number of adaptations that have so far enabled the genus to survive despite dry, nutrient-poor soil, low rates of seed set, high rates of seed predation and low rates of seedling survival. These adaptations include proteoid roots and lignotubers; specialised floral structures that attract nectariferous animals and ensure effective pollen transfer; and the release of seed in response to bushfire.

The arrival of Europeans in Australia has brought new ecological challenges. European colonisation of Australia has directly affected Banksia through deforestation, exploitation of flowers and changes to the fire regime. In addition, the accidental introduction and spread of plant pathogens such as Phytophthora cinnamomi (dieback) pose a serious threat to the genus's habitat and biodiversity. Various conservation measures have been put in place to mitigate these threats, but a number of taxa remain endangered.

Ecophysiology

Ecophysiology (from Greek οἶκος, oikos, "house(hold)"; φύσις, physis, "nature, origin"; and -λογία, -logia), environmental physiology or physiological ecology is a biological discipline that studies the adaptation of an organism's physiology to environmental conditions. It is closely related to comparative physiology and evolutionary physiology. Ernst Haeckel's coinage bionomy is sometimes employed as a synonym.

Edith A. Roberts

Edith Adelaide Roberts (1881 – 1977) was an American botanist studying plant physiology and a pioneer in plant ecology. She created the first ecological laboratory in the United States, promoted natural landscaping along with Elsa Rehmann, and proved that plants were the main source of vitamin A.

Edward James Salisbury

Sir Edward James Salisbury CBE FRS (16 April 1886 – 10 November 1978) was an English botanist and ecologist. He was born in Harpenden, Hertfordshire and graduated in botany from University College London in 1905. In 1913, he obtained a D.Sc. with a thesis on fossil seeds and was appointed a senior lecturer at East London College. He returned to University College London as a senior lecturer, from 1924 as a reader in plant ecology and from 1929 as Quain Professor of botany.

He was director of the Royal Botanic Gardens, Kew from 1943 to 1956. He was responsible for the restoration of the gardens after the Second World War.

He was elected a Fellow of the Royal Society on 15 March 1933 and won the society's Royal Medal in 1945 for "his notable contributions to plant ecology and to the study of the British flora generally". In 1936, he was awarded The Veitch Memorial Medal of the Royal Horticultural Society in acknowledgement of his book The Living Garden (1935), which was enormously popular. In 1939, he received the Commander of the Order of the British Empire and in 1946 he was knighted.

At first, his research was focussed on forest ecology, particularly in his native Hertfordshire. Later, he pioneered investigations of seed size and reproductive output of plants in relation to habitat. He also investigated the ecology of garden weeds and of dune plants.

He was elected President of the Sussex Wildlife Trust in January 1962, where he remained in office until April 1967.

Halophyte

A halophyte is a salt-tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs and seashores. The word derives from Ancient Greek ἅλας (halas) 'salt' and φυτόν (phyton) 'plant'. An example of a halophyte is the salt marsh grass Spartina alterniflora (smooth cordgrass). Relatively few plant species are halophytes—perhaps only 2% of all plant species.

The large majority of plant species are glycophytes, which are not salt-tolerant and are damaged fairly easily by high salinity.

Hardiness (plants)

Hardiness of plants describes their ability to survive adverse growing conditions. It is usually limited to discussions of climatic adversity. Thus a plant's ability to tolerate cold, heat, drought, flooding, or wind are typically considered measurements of hardiness. Hardiness of plants is defined by their native extent's geographic location: longitude, latitude and elevation. These attributes are often simplified to a hardiness zone. In temperate latitudes, the term most often describes resistance to cold, or "cold-hardiness", and is generally measured by the lowest temperature a plant can withstand.

Hardiness of a plant is usually divided into two categories: tender, and hardy. (Some sources also use the erroneous terms "Half-hardy" or "Fully hardy".) Tender plants are those killed by freezing temperatures, while hardy plants survive freezing—at least down to certain temperatures, depending on the plant. "Half-hardy" is a term used sometimes in horticulture to describe bedding plants which are sown in heat in winter or early spring, and planted outside after all danger of frost has passed. "Fully hardy" usually refers to plants being classified under the Royal Horticultural Society classifications, and can often cause confusion to those not using this method.Plants vary greatly in their tolerance of growing conditions, and are capable of adaptation to changes in climate on their own to some extent. The selective breeding of varieties capable of withstanding particular climates forms an important part of agriculture and horticulture. Part of the work of nursery growers of plants consists of cold hardening, or hardening off their plants, to prepare them for likely conditions in later life.

Journal of Ecology

The Journal of Ecology is a bimonthly peer-reviewed scientific journal covering all aspects of the ecology of plants. It was established in 1913 and is published by Wiley-Blackwell on behalf of the British Ecological Society.

The journal publishes papers on plant ecology (including algae) in both terrestrial and aquatic ecosystems. In addition to population and community ecology, articles on biogeochemistry, ecosystems, microbial ecology, physiological plant ecology, climate change, molecular genetics, mycorrhizal ecology, and the interactions between plants and organisms such as animals or bacteria, are published regularly. Besides primary research articles, it publishes "Essay Reviews" and "Forum" articles. In 2008, the first papers in a new series called "Future Directions" were published. These short papers are intended to stimulate debate as to where a field within plant ecology is going, or needs to go.

In addition, the journal contains a long-running series on the "Biological Flora of the British Isles". Over 300 accounts (each of a different species) have been published so far, all of which, from 1998 onwards, can be accessed free of charge via the journal's website. The site also has a list of the species covered.In celebration of the journal’s 100th anniversary, a Centenary Symposium was held during the British Ecological Society’s Annual Meeting in Sheffield (United Kingdom) in September 2011. A group of researchers were invited to talk on topics in which the journal has published major contributions over the last century and in which significant progress is currently being made. The contributors to the Centenary Symposium produced written versions of their papers for publication in the journal's Centenary Special Issue.

According to the Journal Citation Reports, the journal has a 2017 impact factor of 5.172.

Mesophyte

Mesophytes are terrestrial plants which are neither adapted to particularly dry nor particularly wet environments. An example of a mesophytic habitat would be a rural temperate meadow, which might contain goldenrod, clover, oxeye daisy, and Rosa multiflora. Mesophytes prefer soil and air of moderate humidity and avoid soil with standing water or containing a great abundance of salts. They make up the largest ecological group of terrestrial plants, and usually grow under moderate to hot and humid climatic regions.

Plant Ecology (journal)

Plant Ecology is a scientific journal on plant ecology, formerly known as Vegetatio, a journal whose editors resigned in protest of high pricing. The journal publishes original scientific papers on the ecology of vascular plants and terrestrial and aquatic ecosystems. The editor-in-chief is Neal J. Enright (Murdoch University).

Plant community

A plant community (sometimes "phytocoenosis" or "phytocenosis") is a collection or association of plant species within a designated geographical unit, which forms a relatively uniform patch, distinguishable from neighboring patches of different vegetation types. The components of each plant community are influenced by soil type, topography, climate and human disturbance. In many cases there are several soil types within a given phytocoenosis.

A plant community can be described floristically (the species it contains) and/or physiognomically (its physical structure). For example, a forest (a community of trees) includes the overstory, or upper tree layer of the canopy, as well as the understory, further subdivided into the shrub layer, herbaceous layer, and sometimes also moss layer. In some cases of complex forests there is also a well-defined lower tree layer. A plant community is similar in concept to a vegetation type, with the former having more of an emphasis on the ecological association of species within it, and the latter on overall appearance by which it is readily recognized by a layperson.A plant community can be rare even if none of the major species defining it are rare. This is because it is the association of species and relationship to their environment that may be rare. An example is the Sycamore Alluvial Woodland in California dominated by the California sycamore Platanus racemosa. The community is rare, being localized to a small area of California and existing nowhere else, yet the California sycamore is not a rare tree in California.

Plant physiology

Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (biochemistry of plants), cell biology, genetics, biophysics and molecular biology.

Fundamental processes such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed germination, dormancy and stomata function and transpiration, both parts of plant water relations, are studied by plant physiologists.

Resource (biology)

In Biology and Ecology, a resource is a substance or object in the environment required by an organism for normal growth, maintenance, and reproduction. Resources can be consumed by one organism and, as a result, become unavailable to another organism. For plants key resources are light, nutrients, water, and place to grow. For animals key resources are food, water, and territory.

Roger Hnatiuk

Roger James Hnatiuk (born 1946) is a Canadian-Australian botanist specialising in biogeography and plant ecology.

Saponin

Saponins are a class of chemical compounds found in particular abundance in various plant species. More specifically, they are amphipathic glycosides grouped phenomenologically by the soap-like foam they produce when shaken in aqueous solutions, and structurally by having one or more hydrophilic glycoside moieties combined with a lipophilic triterpene or steroid derivative.

Shade tree

A shade tree is a large tree whose primary role is to provide shade in the surrounding environment due to its spreading canopy and crown, where it may give shelter from sunlight in the heat of the summer for people who seek recreational needs in urban parks and house yards, and thus, also protecting them from the sun's harmful UV rays and sunburns. Therefore, some shade trees may be grown specifically for the comfort of the population due to their convenient shelter.

Furthermore, shade trees are also effective in reducing the energy used in cooling homes.

Vegetation

Vegetation is an assemblage of plant species and the ground cover they provide. 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 than the term flora which refers to species composition. Perhaps the closest synonym is plant community, but vegetation can, and often does, refer to a wider range of spatial scales than that term does, including scales as large as the global. Primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, roadside weed patches, wheat fields, cultivated gardens and lawns; all are encompassed by the term vegetation.

The vegetation type is defined by characteristic dominant species, or a common aspect of the assemblage, such as an elevation range or environmental commonality. The contemporary use of vegetation approximates that of ecologist Frederic Clements' term earth cover, an expression still used by the Bureau of Land Management.

Graphical timeline of plant ecologists
21st century in paleontology20th century in paleontology19th century in paleontology18th century in paleontology2040s in paleontology2030s in paleontology2020s in paleontology2010s in paleontology2000s in paleontology1990s in paleontology1980s in paleontology1970s in paleontology1960s in paleontology1950s in paleontology1940s in paleontology1930s in paleontology1920s in paleontology1910s in paleontology1900s in paleontology1890s in paleontology1880s in paleontology1870s in paleontology1860s in paleontology1850s in paleontology1840s in paleontology1830s in paleontology1820s in paleontology1810s in paleontology1800s in paleontology1790s in paleontology1780s in paleontology1770s in paleontology1760s in paleontology1750s in paleontologyWilliam BillingsEmma Lucy BraunHenry GleasonFrederic ClementsHenry Chandler CowlesClinton Hart MerriamEugenius WarmingErnst HaeckelCharles DarwinAlexander von Humboldt21st century in paleontology20th century in paleontology19th century in paleontology18th century in paleontology2040s in paleontology2030s in paleontology2020s in paleontology2010s in paleontology2000s in paleontology1990s in paleontology1980s in paleontology1970s in paleontology1960s in paleontology1950s in paleontology1940s in paleontology1930s in paleontology1920s in paleontology1910s in paleontology1900s in paleontology1890s in paleontology1880s in paleontology1870s in paleontology1860s in paleontology1850s in paleontology1840s in paleontology1830s in paleontology1820s in paleontology1810s in paleontology1800s in paleontology1790s in paleontology1780s in paleontology1770s in paleontology1760s in paleontology1750s in paleontology
Subdisciplines
Plant groups
Plant morphology
(glossary)
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Reproduction
Plant taxonomy
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