Secondary Succession

Secondary succession, defined as following disturbances on already developed soils or previously vegetated substrates, may be considered at plant-demographic timescales, involving a few years, decades, or hundreds of years, if based on the life cycles of certain long-lived tree species.

From: Encyclopedia of Biodiversity (Second Edition) , 2001

Pioneer Species

J.Due west. Dalling , in Encyclopedia of Ecology (Second Edition), 2008

Pioneers in Secondary Succession

Secondary succession occurs when the severity of disturbance is insufficient to remove all the existing vegetation and soil from a site. Many different kinds of disturbances, such as fire, flooding, windstorms, and human activities (e.g., logging of forests) can initiate secondary succession. Pioneers of secondary successions face quite different conditions from those that accompany primary succession. Secondary successions often get-go with resource-rich conditions associated with high low-cal availability and reduced contest for nutrients and wet. Disturbances may also exist short-lived; for instance, gaps created in forest canopies close as the crowns of surrounding copse aggrandize and equally seedlings and saplings in the understory abound up in response to increased low-cal. Pioneers rely on recruitment from propagules present in the soil, or that disperse into the site after disturbance occurs. Pioneers are able to outcompete established vegetation that survived the disturbance past maintaining high juvenile growth rates. Some of the fastest growing trees are pioneers in tropical rain forests. Individuals of the balsa tree Ochroma pyramidale, for example, can grow from seedlings to adults with >xxx   cm trunk diameter in <10 years.

The difference between pioneer and nonpioneer species is hard to delineate (Tabular array 1). Attempts to define distinct life-history strategies (implying coordinated evolution of life-history traits) are confounded because cardinal traits such every bit propagule size and juvenile growth charge per unit tin vary over several orders of magnitude within a community and bear witness wide overlap amongst species with contrasting habitat requirements. However, interactions amid traits can exist used to describe some life-history tradeoffs that largely constrain the habitat requirements of pioneers. For vascular plants, paramount among these is a tradeoff between growth in the sunday and survival in the shade (Fig. 3). The high growth rates of pioneers are maintained by allocating a large fraction of the plant'southward resource to new foliage area production, and by investing in nutrient-rich foliage tissue that can attain loftier-maximum photosynthetic rates. A consequence of preferential allotment to leaf production is that few resources remain that can be used to defend the plant against herbivores and pathogens, or to recover from physical damage. This results in high mortality, especially in the shade, where resources needed for tissue replacement are about limiting.

Table 1. Characteristics of pioneer tree species in tropical forests that distinguish them from nonpioneer species

Pioneer species Nonpioneer species
1. Juveniles recruit from seed post-obit disturbance; seedlings are unable to survive below a wood canopy Seedlings and saplings persist in the shade of a forest awning
2. Seeds germinate in response to cues provided past changes in light, temperature, or soil nitrate concentrations indicating disturbance to canopy vegetation Seeds germinate immediately subsequently dispersal or seasonally during periods favorable for institution
3. Seeds more often than not small-scale; ofttimes dispersed past air current Seeds may be large; frequently dispersed by vertebrates
iv. Seeds often persist in the soil (weeks to decades after dispersal) Seeds lack dormancy or remain in the soil for less than a year
5. Loftier height growth rate and juvenile bloodshed charge per unit Lower height growth, crowns oft show lateral spread in the shade
6. High maximal photosynthetic rate, light compensation point, and foliar food concentrations Low maximal photosynthetic rate, light compensation point, and foliar nutrient concentrations
vii. Short-lived leaves with high leaf area per unit leaf mass Leaves of juvenile plants may persist for several years with depression leaf expanse per unit leaf mass
8. Open canopies with sparse branching Airtight canopies
9. Low wood density Medium–high wood density
x. Depression investment in chemic anti-herbivore defense High investment in chemic and structural defenses
eleven. Oftentimes form defensive mutualisms with ants Defensive mutualisms uncommon
12. Adult lifespan typically &lt;100 years Adult lifespan up to 500 years
13. Wide geographic and ecological range Ofttimes restricted geographic range and habitat requirements

Adapted from Swaine Doc and Whitmore TC (1988) On the definition of ecological species groups in tropical rain forests. Vegetatio 75: 81–86.

Fig. 3

Fig. iii. The negative correlation betwixt annual survival of charge per unit of saplings one–4   cm diameter at breast pinnacle in understory shade versus the median annual growth in the sunday in tree autumn gaps. Data are for canopy and mid-story tree species growing in semi-deciduous tropical woods in the l ha wood dynamics plot on Barro Colorado Island, Panama. Each data bespeak is an individual species. Pioneer species have high growth rates in gaps and low survival in shade. Note that there is a continuum of responses to dominicus and shade that prevents a clear delineation of the pioneer gild. Reproduced from Hubbell SP and Foster RB (1992) Short-term dynamics of a tropical woods: Why ecological inquiry matters to tropical conservation and direction. Oikos 63: 48–61, with permission from Blackwell Publishing.

For pioneers growing in high calorie-free environments, abundant supplies of sugar fixed through photosynthesis can be used to co-opt the services of predaceous insects that defend the plant confronting herbivores. Many pioneers have extra-floral nectaries that provide food for insect mutualists. Two of the ascendant genera of pioneers in tropical forests – Cecropia (Urticaceae) in the neotropics and Macaranga (Euphorbiaceae) in the Asian tropics – take adult a more elaborate mutualism that provides a striking instance of convergent evolution in morphological traits. In both genera the hollow stems of saplings are colonized past queen ants (Crematogaster in Macaranga; Azteca in Cecropia). The emmet colonies are and then provisioned with carbohydrate and lipid-rich food bodies produced on leaf surfaces, stipules, or petioles (Fig. iv).

Fig. 4

Fig. 4. (a) Cecropia engleriana, growing along a roadside in Yasuní National Park, Republic of ecuador. Cecropia spp. are the dominant pioneers of young secondary forests in the neotropics. (b) The hollow stems of virtually Cecropia species are inhabited by aggressive ants (Azteca spp.) that predate insect herbivores. Pointer shows nest entrance. (c) In return, the institute provides the ants with Mullerian food bodies (shown past arrow) produced on the trichilium, a construction at the base of the petiole.

The transient and unpredictable occurrence of secondary successional habitats has selected for high dispersal ability among pioneers. Typically, pioneers are small-seeded reflecting selection for high reproductive output. All the same, seed mass may vary over four orders of magnitude among pioneers within a institute community, reflecting a second life-history tradeoff between colonization success (selecting for small seeds) and institution success (selecting for larger seed reserves). For pioneers with limited dispersal, the probability of colonizing disturbances tin can be increased by maintaining populations of viable seeds in the soil. These soil seed banks may be transient, with seeds lasting a few weeks or months following dispersal, or may exist persistent with seed surviving for decades. In temperate forests nearly seed bank-forming species are annual or perennial herbs. These are typically small-seeded species (<1   mg seed mass) that germinate in response to an increase in the intensity or blood-red:far-ruby ratio of calorie-free associated with openings in the awning or in the litter layer. In tropical forests both trees and herbs grade seed banks with greater seed persistence common among the larger-seeded species (1–100   mg seed mass). Many of these species germinate in response to diurnal temperature fluctuations in the soil associated with big awning gaps.

Changing state-use patterns have led to big increases in the abundance and distribution of many pioneer species. Many of the herbaceous pioneers that were originally restricted to wood gaps, or marginal habitats such as stream banks, have now go economically important weeds in agronomical systems. Similarly, in the tropics, clearance of quondam-growth forests, and abandonment of unproductive agricultural land has provided new habitats for pioneer tree species. Some of these pioneers tin be quite long-lived and can produce valuable timber (east.g., teak, Tectona grandis; and laurel, Cordia alliodora).

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Global Modify and Forest Soils

Hugh D. Safford , 5. Ramón Vallejo , in Developments in Soil Science, 2019

In the MB, secondary succession in oldfields is dominated by highly flammable, obligate seeder shrubs and serotinous pines (especially Aleppo pine, Pinus halepensis), which establish extremely fire-decumbent ecosystems (Santana et al., 2018). Often, in loftier risk areas with frequent human ignitions, these plant formations enter loftier frequency burn down cycles that arrest succession (Baeza et al., 2007) and increment mail service-burn down erosion and ecosystem degradation risk. Serotinous pines are locally eradicated when the fire interval is shorter than their maturity historic period (some fifteen–xx years for Aleppo pino), and burn-prone shrublands develop instead (Pausas et al., 2004). In these atmospheric condition, the recovery of native sclerophyllous vegetation, both tall shrubs and copse, is very slow owing to the low ability of most of these species to disperse to and recruit in new spaces (Vallejo et al., 1999).

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Succession and Colonization

Chryssanthi Antoniadou , ... Chariton-Charles Chintiroglou , in Encyclopedia of Environmental (Second Edition), 2019

Secondary Succession Examples

A well-documented case of secondary succession is the North Carolina Piedmont old-field ( Barbour et al., 1999). The Piedmont area supports a patchy mural of pine and hardwood forests and agronomical fields, and and then, abandoned crops, correspond platonic systems to study secondary succession (Fig. iii). The comparison of community construction through time showed that the cropland was initially colonized past crabgrasses and horseweeds that gave place to white-asters and ragweeds, which in turn gave place to broomsedge and then to pine seedlings. It took about 10   years to reach the phase of immature pines canopy combined with broomsedge. Thereafter, seral stages differed co-ordinate to humidity; in moister sites loblolly pines predominated in contrast to drier sites where shortleaf pines flourished. Gradually, within next fifty years, a hardwood overstory developed in both field types, becoming predominate over pines after near 150   years. Still, the effect of disturbances, such as fires periodically occurring every v–7   years, may maintain erstwhile-fields at the pine seral phase, preventing the development of hardwood forests. Erstwhile-field succession seems to vary according to the biogeographic area whereas in other cases of secondary succession, a gradual overlapping between seral stages has been observed in dissimilarity to the precipitous distinction of seres in Piedmont.

Fig. 3:

Fig. iii. Generalized patterns of terrestrial succession.

The controlling cistron in most secondary succession cases is disturbance; the severity and frequency of disturbances determines bachelor biological legacies initiating customs development. Stand up-replacing fire promotes succession in boreal forests and several studies documented the replacement of shade-intolerant pioneers by shade-tolerant, belatedly-seral species. However, apart from this simplistic explanatory model, specific-site weather condition, initial species composition, structural quality, density dependence, resources levels and intermediate disturbances are also involved leading to converging or diverging successional pathways (Chen and Taylor, 2012).

Successional studies on land ecosystems are typically limited on principal structural plants, not taking into account the associated biota; such studies are enclaved in prolonged field observations linked to the generation length of dominant plants, reaching eons for late-successional tree species. On the contrary, in inland aquatic environments, such as lakes, relevant studies are dealing with the annually repeated seasonal succession of plankton communities, which operates in brusk fourth dimension intervals, usually of few months. A comprehensive report of planktonic secondary succession, in which population and system level indices were applied, is that of the Lake Constance in Alps (Boit and Gaedke, 2014). This is a big, deep and warm monomictic lake of glacial origin with limited external input, in which a typical shift in community composition along succession was observed passing through predictable stages. The authors observed along the successional stages i) college energy transfer efficiency beyond trophic levels, ii) diversification and increasing specialization of consumers on resource exploitation, iii) decrease in total production, iv) increase in functional diversity and complexity of foodwebs. Ongoing grazing pressure, lower prey edibility, lower food quantity and quality, and failing nutrient concentrations were the primary successional drivers.

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Forest Dynamics

Donald L. Grebner , ... Jacek P. Siry , in Introduction to Forestry and Natural Resource, 2013

Summary

Trees located collectively in a woods are likely to be competing with each other for nutrients, light, and h2o. As a group, they class a community and interact in a way partly controlled by the environment, the substrate on which they are located, and their position in the awning. How copse take adjusted to express light resource helps decide the likely ability and success of remaining inside or below their dominant and codominant neighbors. Tree species can limited preferences for niches and may probable be establish growing within distinct environmental gradients that are perchance defined by water and food availability and elevational ranges.

A woods may begin with primary or secondary succession processes. Once established, they by and large transition through stand initiation, stem exclusion, and understory reinitiation stages. Theoretically, if a forest is allowed to grow very old, information technology can accomplish a climax phase, although for practical purposes management of older forests aims to achieve late-successional or former-growth forest conditions. Natural disturbances can force woods succession to return to chief or secondary establishment processes. Disturbances such as tropical cyclones or fires tin exist broadly influential on forest condition and evolution. Smaller disturbances that involve the loss of one or two trees upshot in forest gaps, and an understanding of how trees interact as forest communities and how gaps are formed and filled comprises an essential set of concepts for forest and natural resource managers.

QUESTIONS

(1)

Shade tolerance. Neighbors recently purchased a modest tract of recently harvested forestland in central Alabama. They are somewhat frustrated past their repeated attempts to abound pine trees on the land, in spite of the advanced regeneration of sweetgum and other hardwoods that are now two–three chiliad high. They have no forestry groundwork nor have they sought professional advice. In a short paragraph, describe how you lot would answer, using the shade tolerance of trees as the main topic.

(2)

Observations of forest dynamics. Take a walk or travel to a nearby forest (young, erstwhile, or otherwise). Venture into the wood, abroad from the influences of whatsoever sort of edge. One time there, endeavour to describe the dynamic forest processes that you feel may be occurring. Endeavor also to determine which stage of succession the forest may be encountering. In a brusk, professional presentation to your class, and with a few images captured during your visit, describe these processes.

(three)

Climax and former-growth forests. Some people suggest that the notion of a climax forest is outdated. In a short paragraph, describe your thoughts on the affair. Besides develop a 2nd paragraph that compares the notion of a climax forest with the frequently-used term old-growth. How do these differ, if at all? In a small group of five or six other students, share your opinion of these 2 issues.

(4)

Shade tolerance. Select a group of tree species that commonly abound in your area. For example, in the southern United States 1 might select pines, which would include loblolly pine (Pinus taeda), longleaf pine, shortleaf pine (Pinus echinata), slash pine (Pinus elliottii), swimming pine (Pinus serotina), sand pine (Pinus clausa), and perhaps others. Using a resource that describes the physiological traits of trees (e.m., in Northward America, perchance Silvics of N America), describe in a short memorandum the shade tolerance of the trees you selected and how this might differ among the group.

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Disturbance and succession

Edward A. Johnson , Kiyoko Miyanishi , in Found Disturbance Ecology (Second Edition), 2021

Introduction to the first edition

Natural or anthropogenic disturbance was traditionally viewed as an result that initiated primary or secondary succession, and succession explained the evolution of vegetation in the absence of disturbance. Thus, the concepts of disturbance and succession are inextricably linked in plant ecology.

Succession has been used in and then many different ways and situations that it is almost useless as a precise idea. Still, no matter whether succession has been considered a population (Peet and Christensen, 1980), community (Cooper, 1923a,b; Clements, 1916), or ecosystem (Odum, 1969) phenomenon or procedure, it has contained certain common ideas. Succession is an orderly unidirectional procedure of community change in which communities replace each other sequentially until a stable (self-reproducing) community is reached (see definitions in Abercrombie et al., 1973; Small and Witherick, 1986; Allaby, 1994). The explanation of why and how succession is directed has inverse over its more than hundred-year history, but nearly arguments share the notion that species are adapted to unlike stages in succession and in some way make the surround unsuited for themselves and more suited for the species in the next stage. This grouping selection argument was first instilled into succession in the Lamarckian ideas of Warming, Cowles, and Clements.

Succession arose at the stop of the 1800s and early 1900s out of a naturalist observation tradition when quantitative methods were virtually nonexistent, Aristotelean essentialism (Hull, 1965a,b; Nordenskiöld, 1928) still had a firm grip on how nature should be understood, and meteorology, soil science, biology, and geology were very poorly developed. Further, and equally of import, spatial and temporal scales of ascertainment were express to the scale of a naturalist's sight.

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The roles of mycorrhizas in ecosystems

Sally E Smith , David J Read , in Mycorrhizal Symbiosis (Second Edition), 2002

The Roles of Mycorrhizas in Secondary Successions

While primary successions often embark under weather of nutrient impoverishment, those processes referred to equally secondary succession, which follow disturbance of existing vegetation, are normally initiated in an environment of enrichment, a pulse of N and P being produced past mineralization of residues left by the previous community (Walker and Syers, 1976). The disturbed soil is characteristically first occupied by weedy annuals, especially of families such every bit Chenopo-diaceae, Brassicaceae and Polygonaceae which are effective colonizers and which, since the early work of Stahl (1900), have been considered to exist largely non-mycorrhizal. The conventional interpretation of the basis of the success of these ruderal plants is that as 'r' strategists they have a loftier fecundity, short generation time and an ability chop-chop to exploit pulses of nutrient availability (Grime, 1979). However, the sensitivity, discussed higher up, of many such plants to the presence of VA mycelium raises the possibility that reduction of inoculum potential of these fungi, which is known to arise from disturbance (Miller, 1979; Reeves et al., 1979; Allen and Allen, 1980; Janos, 1980, Jasper et al., 1989, 1992; and see Affiliate 2) is a prerequisite for their success.

Decline of nutrient availability, as the initial flush of minerals is utilized or lost by leaching, leads progressively to competition between plants for resources, and to a situation in which mycorrhizal colonization could be expected to provide a nutritional advantage to plants. A possible role for mycorrhizas in determining the trajectory of successional processes was best-selling by Gorham et al. (1979), who proposed that plants characteristic of a particular stage of succession may have a higher 'analogousness', through their fungal associates, for nutrients at a detail stage. Withal, few ecologists have considered the possibility that mycorrhizas play a pivotal role in successional dynamics. The hypothesis that mycorrhizal colonization might provide hosts with a greater competitive ability and that this leads to acceleration of successional processes was tested by Allen and Allen (1988), who introduced inoculum of VA fungi to a loftier-altitude soil that had been disturbed by open-cast coal mining and was colonized largely past annual 'non-host' species. The presence of inoculum had the effect of reducing the growth of the ruderals and and then in some plots led to increased rates of succession. However, in others, loss of cover provided by the ruderals led to exposure-damage to those species, generally grasses, that had the potential to answer to colonization. Consequently, the rate of succession declined (Allen, 1989). Experiments of this kind demonstrate the complexity of interacting factors that tin influence the successional process and emphasize that above-ground as well as below-ground factors can affect plant response.

Much emphasis has been placed past ecologists upon secondary succession in erstwhile fields, where progressive decrease of availability of N is believed to exist the factor that drives the process (Odum, 1960; Golley, 1965; Tilman, 1987). Following the ruderal phase, a succession of grass species with increasing ability to compete for N is recognized (Tilman, 1990; Tilman and Wedin 1991). Although these grasses are likely to be colonized past VA mycorrhizal fungi, the part of mycorrhizas in determining the result of competitive interactions between them appears not be have been considered. There is much telescopic for work which includes the natural symbionts of these organisms. On theoretical grounds, because the decline in N availability arises partly through progressive inhibition of nitrification and replacement of mobile NO 3 − by relatively immobile NH 4 + ions as the source of mineral N (Robertson and Vitousek, 1981), advantages should increasingly accrue to mycorrhizal plants. Indeed, plants colonized by VA mycorrhizal fungi are likely to have excellent access to P, fifty-fifty when it is in relatively curt supply, so this symbiosis will have the upshot of increasing the emphasis on P as a factor influencing the sucession. In this context information technology is worth noting that the prairie grasses discussed above, were typical of habitats limited by North rather than P availability.

A response seen in some ecosystems to changing N condition is the appearance, as transient occupants, of N-fixing shrubs and trees (van Cleve and Viereck, 1981). In the succession from grassland to boreal or temperate forest, other trees that appear early on are members of the genera Salix and Populus which, in addition to having calorie-free-weight propagules that enhance their capacity for dispersal into successional environments, are characterized by a plasticity which enables them to form both VA and ectomycorrhizas. Compatibility with VA mycorrhizal fungi may be a factor facilitating their incorporation into a turf dominated past VA mycorrhizal grasses or herbs, while associations with ectomycorrhizal fungi would be advantageous in the situation where a progressively greater proportion of the soil Northward is present in organic form.

It has been suggested (Read, 1993) that the modify in North status of an ecosystem from 1 in which inorganic N predominates, to the later condition in which accumulating found residues sequester N largely in organic class, may be the key factor selecting in favour of ectomycorrhizal copse in tardily stages of succession, be they members of the Fagaceae, as in many temperate forests, or of the Pinaceae in boreal forests in the northern hemisphere. By the aforementioned logic, where for reasons of climatic stress, for example at high elevation or latitude, growth of ectomycorrhizal copse is restricted, shrubs with ericoid mycorrhizas that besides have the ability to mobilize nutrients from organic sources are favoured (see Chapter 12). As succession towards ectomycorrhizal forest or heathland proceeds in that location are inevitably stages during which cohorts of species with different types of mycorrhiza coexist. Indeed, even in stable wood communities, weather of soil and irradiance may let the persistence of a herbaceous understory of plants with VA mycorrhizas beneath a canopy of predominantly ectomycorrhizal trees. Nonetheless, here, equally in the heathland state of affairs described earlier, different patterns of root distribution can provide niche separation.Merryweather and Fitter (1995b) show that seedlings of the herb Hyacinthoides non-scripta germinating in the organic matter in ectomycorrhizal Quercus woodland are largely non-mycorrhizal. With time, the developing bulb, and the roots produced from it, descend into mineral soil where they develop VA mycorrhizas in isolation from the largely surface-rooting trees. In effect there are two separate communities, the constituent species of each of which, through their mycorrhizas, are exploiting dissimilar resource. Such differentiation can even be seen at the intraspecific level. Reddell and Malajczuk (1984) observed that Eucalyptus marginata plants formed VA mycorrhizal associations when rooted in mineral soil, but ectomycorrhizas if grown in litter. Plasticity of this kind may exist of particular value in fire-susceptible ecosystems of the kind in which Eucalyptus spp. occur, these being characterized past a cyclical pattern of accumulation and loss of organic resources due to fire.

If, as proposed by some ecologists (e.g. Clements, 1916; Odum, 1971; MacMahon, 1981) succession is a series of anticipated processes, the trajectories of which are primarily influenced past nutritional constraints, a potential clearly exists for mycorrhizal colonization to play a pregnant part in determining both the charge per unit and the direction of the processes. The need, therefore, is for more than field-based experiments which investigate the furnishings of manipulation of mycorrhizal status on the outcome of interaction between species at different stages of the succession. Only by these approaches tin can the real touch on of the symbiosis upon the customs dynamics exist evaluated.

From what has been written earlier in this affiliate it is axiomatic that some design tin exist recognized in the relationship, eventually established in stable, climax communities, between biome and predominant mycorrhizal blazon. On this basis, Read proposed (1984, 1991a,b) that the combination of climatic and soil factors found at any position forth a slope of latitude or altitude selects in favour of that mycorrhizal type that has the functional attributes necessary to enable success of both partners in that environment (Fig. xv.13). There is no doubt that on a global scale, in the absence of disturbance, biome-related segregation of predominant mycorrhizal types tin can exist seen even though a given type rarely, if e'er, occurs to the exclusion of all others. The extent and nature, if whatever, of the involvement of the mycorrhizal symbiosis in determining these observed patterns remains to be investigated by experiment.

Figure 15.13. Diagrammatic representation of the postulated relationship between latitude or distance, climate, soil and mycorrhizal type, together with the development of vegetative mycelium associated with mycorrhizas.

 From Read (1984), with permission. Copyright © 1984

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Global Change and Forest Soils

Víctor J. Jaramillo , Guillermo N. Murray-Tortarolo , in Developments in Soil Science, 2019

Trends in soil carbon and nutrients during secondary succession

Big areas of degraded agronomical and pasture lands in the TDF biome are being abased, allowing for secondary succession with woody species to occur. Secondary forests with different times of recovery are considered the dominant tropical forest type in both wet and dry regions ( Powers and Marín-Spiotta, 2017), although our assessment shows that croplands and pastures are becoming the dominant land cover in the TDF biome (Fig. 7.4). Secondary forests accept received increasing attention in TDF regions (Campo and Vázquez-Yánes, 2004; Lawrence and Foster, 2002; Sánchez-Azofeifa et al., 2009; Urquiza-Haas et al., 2007), merely few have examined biogeochemical changes (eastward.g. Read and Lawrence, 2003; Saynes et al., 2005; Vargas et al., 2008). As a result, knowledge of the role that tropical secondary forests in seasonally dry out regions play on biogeochemical cycles at the global or even regional calibration is yet scarce compared to other tropical biome types.

The current status of enquiry on ecosystem processes and biogeochemistry in secondary tropical forest succession has been recently reviewed by Powers and Marín-Spiotta (2017), with a broad focus including both wet and dry tropical secondary forests. The review plant that soil C stocks may increase, subtract or not modify with secondary succession, with prior land use or direction identified as key drivers of the contrasting trends. The lack of a relationship between wood age and soil C stocks in secondary TDF that follow subsequently agriculture and pasture was reported in a recent study as well (Mora et al., 2018), and is consequent with one of the trends identified past Powers and Marín-Spiotta (2017). In contrast, soil C stocks in forest sites of the Brazilian Caatinga appear to increase significantly, but nonlinearly, with age (de Araújo Filho et al., 2018). Compared with studies of C, those examining trends for other soil elements, such as N and P, during secondary succession are more than rare. Chronosequence studies are few in number and accept been inconclusive for trends in North and P availability, perhaps because factors such as nutrient re-distribution with soil depth or from soil to plant biomass and changes in species composition, can all affect patterns in food availability with succession (Powers and Marín-Spiotta, 2017). A recent review and synthesis showed that soil C, C/Due north, and inorganic N, but not soil bachelor P, recovered through secondary succession in the TDF region of Chamela, United mexican states (Ayala-Orozco et al., 2018). They suggested that woody species richness was a better indicator of soil recovery than wood age. Clearly, global change drivers such as climate and sequential clearing of secondary forests for production affect the trends during succession, and as Powers and Marín-Spiotta (2017) betoken, the soil trends are less predictable than the trends of aboveground processes.

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ECOLOGY | Natural Disturbance in Forest Environments

D.F.R.P. Burslem , in Encyclopedia of Wood Sciences, 2004

Forest Growth Cycle

The processes of tree death and regeneration described above are intrinsic to all natural wood communities. They provide examples of internal secondary successions that arise considering of the uneven-aged structure of most natural forest communities. The heterogeneous nature of woods limerick and history creates a mosaic of patches at different stages in the forest growth cycle. Experienced foresters and ecologists take attempted to map the distribution of patches at different stages using species composition and wood structure equally indicators of patch status, although these efforts are inherently express by the depression degree of spatial coverage relative to inherent spatial heterogeneity. Notwithstanding, in one well-replicated study of a semideciduous forest in Panama, approximately 0.1% of the ground surface expanse was covered by awning gaps (defined every bit contiguous areas of at least 25  thousand2 in which the height of the canopy is <5   1000).

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Volume 2

Paulina Wietrzyk-Pełka , Michał Hubert Węgrzyn , in Encyclopedia of the World'south Biomes, 2020

Introduction—What Is the Master Succession Process?

The succession process is defined as species change over time and it is divided into ii types: primary succession occurring on substrates with no previous biological life; and secondary succession happening on substrates with a biological legacy that has been disturbed. The processes of primary succession on a barren substrate by living organisms are rarely observed in nature. There are only a few places where the conditions for the existence of these phenomena are possible: areas submerged with lava after volcanic eruptions, volcanic islands emerging from the sea, and areas recently exposed from beneath the ice. These provide a natural laboratory where we tin can trace ecosystem formation from the primeval stages. Primary succession begins when microorganisms, plants and animals start to colonize a new substrate. Here nosotros will focus on plant succession and vegetation development in glacier forelands in the Chill.

At the beginning of 20th century, Clements (1916) proposed an arroyo in which succession has a linear and directional graphic symbol and ends in a final climax community. This view has been questioned by Gleason (1917, 1926) and farther elaborated past Egler (1954), Drury and Nisbet (1973) and Whittaker (1974). Currently, primary succession is not e'er considered as a linear procedure due to the turnover of the component species. Therefore the process rarely reaches species equilibrium (Walker and del Moral 2003).

Climate change is currently driving the expansion of ice-free areas in glacier forelands, indicating the need for research on the primary succession. Consequently, Arctic regions offer perfect opportunities for studying this processes on the freshly deglaciated areas gradually inhabited by unlike groups of organisms: microorganisms, lichens, bryophytes and vascular plants (Frenot et al., 1998). The procedure of colonization depends not only on availability of diaspores of surrounding vegetation (Bullock et al., 2002; Jones and del Moral, 2009; Del Moral and Erin, 2004; Řehounková and Prach, 2006), just besides on the various abiotic factors that narrate the habitat (Matthews, 2008), and geomorphological processes shaping the surface after the disappearance of ice. As a effect, interdisciplinary research combining botany, geomorphology, meteorology and soil scientific discipline is needed to provide a detailed knowledge of principal succession. Currently, research on the succession on glacier forelands is however needed considering of the rapid growth of ice-gratuitous areas and the increasing rate of melting glaciers due to climatic change (Laspoumaderes et al., 2013). There are yet mechanisms and environmental factors influencing these processes that have not yet been investigated (Walker and del Moral, 2003; Prach and Rachlewicz, 2012).

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Australia, Biodiversity of Ecosystems

Raymond Louis Specht , Alison Specht , in Encyclopedia of Biodiversity (2nd Edition), 2013

Postfire Succession

The shading effect of the overstory on the species richness in the understory has been demonstrated when long-lived shrubby species, such as Banksia ornata (Proteaceae), regenerate from seed in a secondary succession following the burn that regularly razes Australian heathlands ( Figure ix). Application of phosphate fertilizer to these food-poor ecosystems results in more than rapid growth of overstory shrubs to the detriment of the understory species (Specht and Specht, 1989c).

Figure 9. The species richness of Dark Island heathland, South Commonwealth of australia (Specht and Specht, 1989c) decreased as foliage cover of the overstory (Banksia ornata, B. marginata, Allocasuarina pusilla, and Xanthorrhoea caespitosa) increased with time after burn command (C) and with phosphate fertilizer (F).

Long-lived overstory species, regenerating from root-stocks after fire, rapidly develop maximum leafage projective cover in the overstory which shades out understory plants. However, the sum of the foliage projective covers of overstory and understory strata remains a constant throughout the postal service-burn down succession (Specht, 1969).

Tall open up-forests of mountain ash (Eucalyptus regnans) in south-eastern Australia are killed past fire. Dense stands of saplings soon regenerate and over-shadow developing understory plants. Gradually over many decades the leafage projective embrace of the overstory thins to the norm for the aerodynamic climate of the region and enables the understory to develop (Ashton, 1976).

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