Pioneer species

Pioneer species are resilient species that are the first to colonize barren environments, or to repopulate disrupted biodiverse steady-state ecosystems as part of ecological succession. A number of kinds of events can create good conditions for pioneers, including disruption by natural disasters, such as wildfire, flood, mudslide, lava flow or a climate-related extinction event^[1] or by anthropogenic habitat destruction, such as through land clearance for agriculture or construction or industrial damage. Pioneer species play an important role in creating soil in primary succession, and stabilizing soil and nutrients in secondary succession.^[2]

For humans, because pioneer species quickly occupy disrupted spaces they are sometimes treated as weeds or nuisance wildlife, such as the common dandelion or stinging nettle.^[3]^[2] Even though humans have mixed relationships with these plants, these species tend to help improve the ecosystem because they can break up compacted soils and accumulate nutrients that help with a transition back to a more mature ecosystem.^[4]^[5]^[2] In human managed ecological restoration or agroforestry, trees and herbaceous pioneers can be used to restore soil qualities and provide shelter for slower growing or more demanding plants.^[5]^[6]^[7] Some systems use introduced species to restore the ecosystem,^[2] or for environmental remediation.^[8] The durable and characteristics of pioneer species can also make them to become potential invasive species, or interfere with biodiversity by quickly occupying an area.^[9] ^[2]^[10]

Pioneer flora

Some lichens grow on rocks without soil, so may be among the first of life forms, and break down the rocks into soil for plants.^[11] Since some uninhabited land may have thin, poor quality soils with few nutrients, pioneer species are often hardy plants with adaptations such as long roots, root nodes containing nitrogen-fixing bacteria, and leaves that employ transpiration. Note that they are often photosynthetic plants, as no other source of energy (such as other species) except light energy is often available in the early stages of succession, thus making it less likely for a pioneer species to be non-photosynthetic.

The plants that are often pioneer species also tend to be wind-pollinated rather than insect-pollinated, as insects are unlikely to be present in the usually barren conditions in which pioneer species grow; however, pioneer species tend to reproduce asexually altogether, as the extreme or barren conditions present make it more favourable to reproduce asexually in order to increase reproductive success rather than invest energy into sexual reproduction. Pioneer species will eventually die, create plant litter, and break down as "leaf mold" after some time, making new soil for secondary succession (see below), and releasing nutrients for small fish and aquatic plants in adjacent bodies of water.^[12]

Some examples of pioneering plant species:

Barren sand - lyme grass (Leymus arenarius), sea couch grass (Agropyron pungens), Marram grass (Ammophila breviligulata)
Salt water - green algae, marine eel grass (Zostera spp.), pickleweed (Salicornia virginica), and cordgrass (hybrid Spartina × townsendii) and (Spartina anglica).
Clear water - algae, mosses, freshwater eel grass (Vallisneria americana).
Solidified lava flows (volcanic rock) -
- in Hawaii: swordfern (Polystichum munitum), ‘ōhi‘a lehua (Metrosideros polymorpha), ‘ohelo (Vaccinium reticulatum) and ‘āma‘u (Sadleria cyatheoides);^[13]
- on Surtsey: lichen (Stereocaulon vesuvianum and Placopsis gelida) and moss (Racomitrium ericoides);^[14] green algae
Disturbed areas such as construction sites, road cuttings and verges, cultivated lands - see ruderal species
Bare clay - Orchids
Mountains - Lichens

Pioneer fauna

On land

The pioneering fauna will colonize an area only after flora and fungi have inhabited the area. Soil fauna, ranging from microscopic protists to larger invertebrates, have a role in soil formation and nutrient cycling. Bacteria and fungi are the most important groups in the breakdown of organic detritus left by primary producing plants such as skeletal soil, moss and algae. Soil invertebrates enhance fungal activity by breaking down detritus. As soil develops, earthworms and ants alter soil characteristics. Worm burrows aerate soil and ant hills alter sediment particle size dispersal, altering soil character profoundly.

Though vertebrates in general would not be considered pioneer species, there are exceptions. Natterjack toads are specialists in open, sparsely vegetated habitats which may be at an early seral stage.^[15] Wide-ranging generalists visit early succession stage habitats, but are not obligate species of those habitats because they use a mosaic of different habitats.

Vertebrates can affect early seral stages. Herbivores may alter plant growth. Fossorial mammals could alter soil and plant community development. In a profound example, a seabird colony transfers considerable nitrogen into infertile soils, thereby altering plant growth. A keystone species may facilitate the introduction of pioneer species by creating new niches. For example, beavers may flood an area, allowing new species to immigrate.^[16]

Under water

The concept of ecologic succession also applies to underwater habitats. If a space becomes newly available in a reef surrounding, haplosclerid and calcareous sponges are the first animals to initially occur in this environment in greater numbers than other species. These types of sponges grow faster and have a shorter life-span than the species which follow them in this habitat.^[17]

Secondary succession and pioneer species

The term pioneer species is also used to refer to the first species, usually plants, to return to an area after disturbance as part of the process of secondary succession. Disturbances may include floods, tornadoes, forest fires, deforestation, or clearing by other means.^[18]

Pioneer species tend to be fast-growing, shade-intolerant, and tend to reproduce large numbers of offspring quickly. The seeds of pioneer species can sometimes remain viable for years or decades in the soil seed bank and often are triggered to sprout by disturbance.^[19] Mycorrhizal fungi have a powerful influence on the growth of pioneer species.^[20]

Some examples of the plants in such areas include:^{[citation needed]}

Raspberry - Rubus spp.
Heaths - Ericaceae spp.
Graminoids, forbs, and wildflowers - native, introduced, and invasive species: such as fire dependent seed, cone, and resprouter chaparral genera.^[21]

References

^ Duram, Leslie A. (2010). Encyclopedia of Organic, Sustainable, and Local Food. ABC-CLIO. p. 48. ISBN 9780313359637.
^ ^a ^b ^c ^d ^e Dalling, J. W. (2008-01-01), "Pioneer Species", in Fath, Brian (ed.), Encyclopedia of Ecology (Second Edition), Oxford: Elsevier, pp. 181–184, ISBN 978-0-444-64130-4, retrieved 2024-04-13
^ "Taraxacum officinale". www.fs.usda.gov. Retrieved 2024-04-13.
^ Cacace, Claudio; García-Gil, Juan C.; Cocozza, Claudio; De Mastro, Francesco; Brunetti, Gennaro; Traversa, Andreina (2022-11-03). "Effects of different pioneer and exotic species on the changes of degraded soils". Scientific Reports. 12 (1): 18548. Bibcode:2022NatSR..1218548C. doi:10.1038/s41598-022-23265-y. ISSN 2045-2322. PMC 9633587. PMID 36329111.
^ ^a ^b Steinfeld, Jonas P.; Miatton, Massimiliano; Creamer, Rachel E.; Ehbrecht, Martin; Valencia, Vivian; Ballester, Maria Victoria Ramos; Bianchi, Felix J. J. A. (2024-03-01). "Identifying agroforestry characteristics for enhanced nutrient cycling potential in Brazil". Agriculture, Ecosystems & Environment. 362: 108828. Bibcode:2024AgEE..36208828S. doi:10.1016/j.agee.2023.108828. ISSN 0167-8809.
^ Swinfield, Tom; Afriandi, Roki; Antoni, Ferry; Harrison, Rhett D. (2016-12-01). "Accelerating tropical forest restoration through the selective removal of pioneer species". Forest Ecology and Management. 381: 209–216. Bibcode:2016ForEM.381..209S. doi:10.1016/j.foreco.2016.09.020. ISSN 0378-1127.
^ Cortines, Erika; Valcarcel, Ricardo (October 2009). "Influence of pioneer-species combinations on restoration of disturbed ecosystems in the Atlantic Forest, Rio de Janeiro, Brazil". Revista Árvore. 33 (5): 927–936. doi:10.1590/S0100-67622009000500015. ISSN 0100-6762.
^ Wu, Jiamei; Zhang, Chenxu; Yang, Huifen; Chen, Pan; Cao, Jian (January 2023). "Combined Remediation Effects of Pioneer Plants and Solid Waste towards Cd- and As-Contaminated Farmland Soil". Applied Sciences. 13 (9): 5695. doi:10.3390/app13095695. ISSN 2076-3417.
^ Swinfield, Tom; Afriandi, Roki; Antoni, Ferry; Harrison, Rhett D. (2016-12-01). "Accelerating tropical forest restoration through the selective removal of pioneer species". Forest Ecology and Management. 381: 209–216. Bibcode:2016ForEM.381..209S. doi:10.1016/j.foreco.2016.09.020. ISSN 0378-1127.
^ Seidler, Reinmar (2024-01-01), "Biodiversity in Anthropogenically Altered Forests", in Scheiner, Samuel M. (ed.), Encyclopedia of Biodiversity (Third Edition), Oxford: Academic Press, pp. 80–97, ISBN 978-0-323-98434-8, retrieved 2024-04-13
^ Sharnoff, Sylvia; Sharnoff, Stephen. "Lichen Biology and the Environment". Lichens of North America.
^ Walker, Lawrence R.; Moral, Roger del (2003-02-13). Primary Succession and Ecosystem Rehabilitation. Cambridge University Press. ISBN 9780521529549.
^ Amazing Lava Products and Forms, U.S. National Park Service. Retrieved 2015-06-16.
^ "Surtsey - Colonization of the land".
^ Faucher, Leslie; Hénocq, Laura; Vanappelghem, Cédric; Roundel, Stephanie; Tocqueville, Robin; Galina, Sophie; Godé, Cécile; Jaquiéry, Julie; Arnaud, Jean-Francois (2017-09-01). "When new human-modified habitats favor the expansion of an amphibian pioneer species: Evolutionary history of the natterjack toad (Bubo calamity) in a coal basin". Molecular Ecology. 26 (17): 4434–4451. Bibcode:2017MolEc..26.4434F. doi:10.1111/mec.14229. hdl:20.500.12210/34525. ISSN 1365-294X. PMID 28667796. S2CID 25656968.^{[permanent dead link]}
^ Wall work, John Anthony (1970). Ecology of Soil Animals. McGowan-Hill. ISBN 978-0070941250.
^ J. Vicente, M. A. Timmers, M. K. Webb et. al (2022) Ecological succession of the sponge cryptofauna in Hawaiian reefs add new insights to detritus production by pioneering species.Scientific Reports, 20452322, 9/5/2022, Vol. 12, Iss. 1 doi:10.1038/s41598-022-18856-8
^ Ricklefs, Robert E.; Relyea, Rick; Richter, Christoph F. (2014-07-20). Ecology: The Economy of Nature (Seventh edition, Canadian ed.). New York, NY: W. H. Freeman. ISBN 9781464154249. OCLC 961903099.
^ Dalling, James W.; Brown, Thomas A. (2009). "Long-Term Persistence of Pioneer Species in Tropical Rain Forest Soil Seed Banks". The American Naturalist. 173 (4): 531–535. doi:10.1086/597221. PMID 19228112. S2CID 11269697.
^ Zangaro, W; Nisizaki, S.M.A; Domingos, J.C.B; Nakano, A.M. (2003). "Mycorrhizal Response and Successional Status in 80 Woody Species from South Brazil". Journal of Tropical Ecology. 19 (3): 315–324. doi:10.1017/S0266467403003341. S2CID 86302550.
^ Knox, Kirsten J. E.; Morrison, David A. (2005-06-01). "Effects of inter-fire intervals on the reproductive output of resprouters and obligate seeders in the Proteaceae". Austral Ecology. 30 (4): 407–413. Bibcode:2005AusEc..30..407K. doi:10.1111/j.1442-9993.2005.01482.x. ISSN 1442-9993.