Early Stages Of Secondary Succession Research Articles

Land degradation of abandoned croplands in the Xilingol steppe region, Inner Mongolia, China.

Steppe grasslands are distributed over vast areas in arid and semiarid regions of Eurasia. However, steppe grasslands face desertification or degradation caused by human over‐activity. In the last decades, steppe regions have seen increased areas of crop cultivation and subsequent abandonment due to inappropriate agricultural management. Land degradation of abandoned croplands has become a common problem in the Inner Mongolia Autonomous Region, China. A field survey was conducted in the Xilingol steppe, and vegetation was classified into three groups. Based on comparisons of species composition and soil characters, group 1 represents steppe grassland, group 2 represents abandoned croplands and group 3 represents yardangs. The typical indicator species of steppe, abandoned croplands and yardangs are Leymus chinensis, Cleistogenes squarrosa and Elymus dahuricus, respectively. Abandoned croplands are exposed to wind and rain, resulting in soil erosion, which not only increases coarse sand content but also decreases total carbon and total nitrogen in the soil. We found that soil condition is an important factor affecting the early stages of secondary succession in abandoned croplands and that farming in typical steppes might contribute to land degradation. We concluded that abandoned croplands can be converted to yardangs by erosion. The extension of yardangs might then lead to desertification in steppe regions. Land managers should be aware that farming in typical steppes is associated with a risk of desertification. The degree of degradation of steppe can be measured by monitoring these indicator species.

Assessment of flora, plant communities, and hydrochemical conditions for adaptive management of a small artificial wetland made in a park of a cool-temperate city

In order to recreate the landscape of Ishikari Mire, an artificial wetland was made in 2000 at a city park in northern Japan. Its flora, plant communities, and hydrochemical conditions were examined in 2005 and compared with those determined in 2001 and with those of nearby intact fens. Management increased water levels by ca. 10 cm from 2002. Neutral pH, high electrical conductivity (EC), and high concentrations of nitrogen and mineral ions were the same as in 2001, but higher than in fens. The wetland was flooded by river water a few times every year. These hydrochemical conditions suit the growth of fen species. Total species increased from 73 (2001) to 105 (2005), whereas annuals and biennials decreased from 20 to 13 and naturalized exotic species from 18 to 15. Five naturalized exotic species that disappeared by 2005 were all mesophytes, and one of two newly found naturalized exotic species was a hygrophyte. Accordingly, the rapid change can be explained by the change of lifeforms in the early stage of secondary succession, and in some parts, by the disappearance of mesophytic plants as wetness increased. During the 6 years, the wetland communities changed toward that of fens because most of the migrated or imported fen species were increasing. Many other fen plants, therefore, would be able to grow in the wetland, while only four fen species had migrated. Accordingly, importation of other fen plants is essential to recreate the whole plant assemblages of mire.

Carbon cycling and net ecosystem production at an early stage of secondary succession in an abandoned coppice forest

Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004-2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha(-1 )year(-1), including below-ground coarse roots; this was partitioned into 2.5 tC ha(-1 )year(-1) biomass increment, 1.6 tC ha(-1 )year(-1) foliage litter, and 1.0 tC ha(-1 )year(-1) other woody detritus. The total amount of annual soil surface CO(2) efflux was 6.8 tC ha(-1 )year(-1), which included root respiration (1.9 tC ha(-1 )year(-1)) and heterotrophic respiration (RH) from soils (4.9 tC ha(-1 )year(-1)). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (-1.6 tC ha(-1 )year(-1)), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha(-1 )year(-1)) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.

Competition between and within aspen(populus tremula) and raspberry(rubus idaeus) after clear‐cutting: Matrix models of structured populations dynamics

The study aims to understand the life histories and ensuing population dynamics of Rubus idaeus and Populus tremula during their early stage of secondary succession following clear‐cutting. Dynamics of raspberry and aspen populations are described by meens of special kind of matrix population model, which takes into account both the chronological age and the ontogenetic stage of individual plants. Modelling relies upon data sets from clear‐cut areas of the Central Forest Reserve (Russia). Observations on the permanent sample plots for 8 years provided data which were used the linear matrix models of single‐species population growth and for a nonlinear model of two competing species dynamics during succession. Relatively large numbers of age‐stage groups for two competing populations were aggregated into a system consisting of a few macro‐groups formed by their functional role in the competition processes. The aggregated, low‐dimensional model demonstrates biologically interpretable competition outcomes and shows that different boundary steady states with exclusion of one or more macro‐groups are possible.

Bat diversity and abundance associated with the degree of secondary succession in a tropical forest mosaic in south‐eastern Mexico

AbstractUnder the hypothesis that bat diversity would be lower in the early stages of secondary succession and that species affected negatively by habitat modification would be more frequent in later successional stages, we evaluated how bats use 12 vegetation stands representing four stages of secondary succession, following disturbance caused by slash‐and‐burn agriculture and selective logging. We compared bat richness, abundance and diversity, and found that none of these variables was different among stages or rainy seasons. However, of the 10 most common bat species, two were significantly more abundant in stands at the early stages of secondary succession, while the opposite was true for three other species. Canopy cover mainly explains these patterns. Rainy season had no effect on the abundance of the common species. The results of this study indicate that although some frugivorous species were very abundant in the younger stands, the majority of the rare species were captured in older stands. The absence of rare and habitat‐specialized species from young successional stages close to primary forest suggests that, for effective bat conservation in landscapes modified by human activity, areas with original vegetation should be maintained to ensure the survivorship of sensitive‐to‐deforestation species.

Effects of burning strength in shifting cultivation on the early stage of secondary succession in Sarawak, Malaysia

The effects of burning strength in shifting cultivation on the early stage of secondary succession in tropical rain forest was investigated at four sites (Sabal, Balai Ringin, Niah, and Bakam) in Sarawak, Malaysia. The number and growth (diameter, height, and biomass) of germinated seedlings were measured in experimental shifting cultivation plots in which the burning strength varied between 0, 100, 200, and 300 t/ha at Sabal, Balai Ringin, and Niah and 0, 20, and 100 t/ha at Bakam. Species composition of germinated tree and herbaceous seedlings was surveyed, and a germination test of buried seed was conducted at Niah and Bakam. The number of germinated seedlings decreased with increasing burning strength, whereas seedling growth was promoted by burning. During the first year, growth was best in the intermediate burning strength plots, whereas during the second year, growth was best in the most strongly burned plots. Species composition differed between unburned and burned sites. Site-specific factors such as original stand biomass, soil properties, and invasion of exotic species also affected germination and growth. Buried seeds in the Ao layer were killed by burning, and nearly all seeds in the 0-5 cm layer were killed in the plots with the highest burning strength (> 100 t/ha). On the basis of our findings, we conclude that in shifting cultivation systems burning promotes vegetation recovery when the burning strength is properly managed.

The Demography of Miconia prasina (Melastomataceae) During Secondary Succession in Puerto Rico1

ABSTRACT Miconia prasina (Melastomataceae) is an important colonizing species during early stages of secondary succession in Puerto Rico but its abundance declines with increasing stand age. We studied its demography for 2 yr (1995–1997) in three populations across a pasture to forest chronosequence (1‐, 12‐, and 25‐yr old) and in one population in a hurricane‐disturbed older forest (>60‐yr old). Vegetative growth was positive in the two young sites, but negative in the two older sites. The highest percentage of plants that flowered occurred in the two younger sites but highest seed production occurred in the 25‐yr‐old site. Although seed germination occurred in the two older sites, no seedlings established. Vegetative reproduction (root sprouts) was found in all sites, with most sprouts occurring in young sites. The 2 yr of census data were used to construct stage‐based transition matrices. In the two young sites, the average population growth rate was positive (λ > 1), while average population growth was negative in the two older sites (λ < 1). Elasticity, a measure of the effects of proportional changes in life‐history transitions to the long‐term population growth rate, varied across both stages and sites. Elasticity shifted from large plants in young sites to small plants in older sites. Across all sites, elasticities related to survival were more important than those of growth or vegetative reproduction. The demographic analysis supported the previous observations of changes in the density of M. prasina based on the chronosequence and also suggests that establishment via seeds must occur prior to abandonment in active pastures.

The role of below-ground competition during early stages of secondary succession: the case of 3-year-old Scots pine (Pinus sylvestris L.) seedlings in an abandoned grassland

In abandoned or extensively managed grasslands, the mechanisms involved in pioneer tree species success are not fully explained. Resource competition among plants and microclimate modifications have been emphasised as possible mechanisms to explain variation of survivorship and growth. In this study, we evaluated a number of mechanisms that may lead to successful survival and growth of seedlings of a pioneer tree species (Pinus sylvestris) in a grass-dominated grassland. Three-year-old Scots pines were planted in an extensively managed grassland of the French Massif Central and for 2 years were either maintained in bare soil or subjected to aerial and below-ground interactions induced by grass vegetation. Soil temperatures were slightly higher in bare soil than under the grass vegetation, but not to an extent explaining pine growth differences. The tall grass canopy reduced light transmission by 77% at ground level and by 20% in the upper part of Scots pine seedlings. Grass vegetation presence also significantly decreased soil volumetric water content (Hv) and soil nitrate in spring and in summer. In these conditions, the average tree height was reduced by 5% compared to trees grown in bare soil, and plant biomass was reduced by 85%. Scots pine intrinsic water-use efficiency (A/g), measured by leaf gas-exchange, increased when Hv decreased owing to a rapid decline of stomatal conductance (g). This result was also confirmed by delta 13C analyses of needles. A summer 15N labelling of seedlings and grass vegetation confirmed the higher NO3 capture capacity of grass vegetation in comparison with Scots pine seedlings. Our results provide evidence that the seedlings' success was linked to tolerance of below-ground resource depletion (particularly water) induced by grass vegetation based on morphological and physiological plasticity as well as to resource conservation.

Early stages of secondary succession on abandoned cropland in north‐east Borneo Island

A study on community structure and floristic change in the early stages of the tropical old‐field succession in an intensive shifting cultivation area, Sabah, north‐east Borneo Island, was conducted in March and September 1997. Dense therophytic communities were established soon after abandonment, and rapidly changed: namely, from Galinsoga parviflora (in approximately 1–2 months) to Crassocephalum crepidioides (in approximately 3–5 months) and further to Conyza sumatrensis (in approximately 1 year). These therophytic communities were replaced by perennial grass and shrub species, such as Imperata cylindrica and Eupatorium odoratum, within 3 years after abandonment. At this stage, a few pioneer tree species such as Trema orientalis made a sparse canopy layer approximately 3–4 m high. The three pioneer annuals have wind‐dispersed small seeds. The plant densities of the three annuals did not appear to change between areas fallow for 1 month and 4 months. Almost all of the seedlings of the three annuals might simultaneously have invaded the fallowed field soon after abandonment. The three pioneer annuals take a different amount of time to reach their respective mature sizes. This resulted in the rapid successional changes in the tropical old‐field succession. The seed‐bank annuals, whose seeds germinate after the winter pre‐chilling, occurred in the temperate old‐fields as the first‐year pioneers under seasonal condition. Intermittent shifting cultivation and tropical conditions without seasonality favour the occurrence of wind‐dispersed annuals with a spatially fugitive strategy.

Carbon input from plant to soil through root exudation inDigitaria adscendensandAmbrosia artemisiifolia

The amount of carbon released into soil through root exudation by Digitaria adscendens Herrm. and Ambrosia artemisiifolia L. var. elatior Desc., which often predominate at the early stages of secondary succession, was evaluated in a laboratory experiment conducted over a 60-day period. Differences in the amount of exuded carbon between these species and between the developmental stages were examined. The amount of carbon exuded increased with growth in both species. The percentage of exuded carbon to photosynthetically net fixed carbon, which was higher at younger stages (13%) in D. adscendens, decreased to 3.1% with time. On the other hand, no reduction in the amount of carbon exuded was observed in A. artemisiifolia (4.7–8.1% range). The total amount of carbon released through root exudation in D. adscendens and A. artemisiifolia was estimated at 3.1% and 6.9% of photosynthetically net fixed carbon, respectively. These results suggest the possibility that wild plants exude a considerable amount of carbon from their roots to the soil, and emphasizes the necessity for considering root exudation in the carbon cycle.

Early herbaceous succession along a topographical gradient on forest clear‐felling sites in mountainous terrain, central Japan

AbstractEarly successional patterns of herbaceous communities in forest clear‐felling sites were investigated along a topographical gradient, which included ridge, slope and valley habitat types, in warm‐temperate evergreen forest regions of central Japan for 5 years. Three dominant species with wind‐dispersed seeds played a major role in the succession: an annual, Crassocephalum crepidioides, a biennial, Erigeron canadensis, and a perennial, Miscanthus sinensis. Pioneer herbs that have a seed‐bank strategy, which are common in old field succession, were not found in the mountainous sites. The persistence of the annual or biennial dominants during the very early stages of secondary succession was different in the three topographical habitat types. In the ridge habitat, M. sinensis dominated from the first year state, and C. crepidioides and E. canadensis were less prominent. Crassocephalum crepidioides and E. canadensis became dominant as one moved down the slope. In the valley habitat, C. crepidioides dominated in the first year stage, was succeeded by E. canadensis in the second year, and then M. sinensis gradually replaced it in later years. As all three wind‐dispersed dominants simultaneously invaded in all the habitat types after clear‐felling, the different successional patterns along the topographical gradient might have resulted from differences in the establishment ability and the growth rate of the three dominants depending on the three habitat types.

Early Stages of Secondary Succession Recorded in Soil Pollen on the North Carolina Piedmont

-Conditions just prior to field abandonment and the early stages of forest regeneration have residual effects on patterns of forest regeneration, but are often not available for study. The potential of pollen preserved in acidic soils to reconstruct land-use immediately before field abandonment was tested here by comparing known stand histories with analysis of pollen which had washed downward into the soil. Large amounts of Ambrosia in the soil pollen, accompanied by Asteraceae and Poaceae, indicated that a site was a plowed field prior to the start of forest regeneration. Abrupt shifts in proportions of Pinus and Quercus pollen correlated with known logging histories. Sites of unknown history included similar diversity in the proportions of nonarboreal pollen, and no evidence of logging. Proportions of tree taxa in soil pollen and vegetation surveys correlated only weakly. Soil pollen analysis, under appropriate conditions of pollen preservation, can provide evidence of major differences in site histories for which there is otherwise little evidence.

Nitrogen and Phosphorus Effects on Secondary Succession Dynamics on a Semi‐Arid Sagebrush Site

A sagebrush steppe community in northwestern Colorado was disturbed in 1984 and subjected to annual applications of nitrogen and phosphorus, and successional responses were studied over a 5—yr period. Phosphorus was not found to be significant but nitrogen did significantly affect succession for all years except the first. Three seral groups developed on the non—fertilized plots, the first two dominated by annuals and lasting 3 yr, the third transitional and dominated by perennials. The addition of N altered this successional pattern by allowing annuals to remain as site dominants through the 5th yr. Results of this study suggest that dominance of a site by annuals in early stages of secondary succession is related to high nutrient availability.

Development of Surface Structure of Andosol in Early Stages of Secondary Succession at Sugadaira, Central Japan

Development of Surface Structure of Andosol in Early Stages of Secondary Succession at Sugadaira, Central Japan

Species Strategy in Early Stage of Secondary Succession Associated with Soil Properties Status in a Lowland Mixed Dipterocarp Forest and Kerangas Forest in East Kalimantan.

Studies on the early secondary succession were carried out in a lowland mixed Dipterocarp forest and a kerangas (heath) forest in East Kalimantan, Indonesia. The results show that there is a correlation between the species strategy with the physical and chemical soil status in the early secondary succession. In Mixed Dipterocarp Forest (Red- Yellow Podzolic soils) seedlings of secondary species were important as the initial colonizers. In contrast, vegetative resprouts (trees and shrubs) were the main component of Kerangas Forest (Podzol soils). A model of species strategy in relation to changes in soil property associated with the early secondary succession is presented.

Population structure and succession in temperate forests of southwestern Japan

In the temperate forests of southwestern Japan, the population density of woody plants in the community increases in the early stage of secondary succession, reaches a peak in the old oak-chestnut forest, and decreases towards the climax beech forest. The species richness and diversity of woody plants also show a trend similar to that of the population density. The canopy-tree population decreases in the course of the succession while the basal area increases, showing a self-thinning process. The species richness, diversity and population density of herbaceous plants are much influenced by the dominance of the bamboo, Sasa palmata. The life-history traits of trees, lower trees and shrubs are discussed in relation to their shoot system, reproductive pattern and successional processes.

Herbaceous vegetation development and weed potential in slash and burn agriculture (Jhum) in N. E. India

SummaryThe patterns of herbaceous vegetation development and weed potential following slash and burn clearing after different lengths of time between the cultivation cycles are described. The early stages of secondary succession following burning tended to conform closely to the ‘initial floristic compositione’ model under shorter cycles of 4 and 6 years between cultivation, but the ‘relay floristicse’ model was found to be more applicable to the cycles of 10 and 20 yearse’ duration. Weed population, in terms of density, biomass and germinable seeds present in the soil, was significantly higher after cycles of 4 and 6 years compared to 10‐ and 20‐year cycles. In all the cycles, however, weed population declined sharply after a year of cropping with an effective weeding programme following the burn.

Experimental studies on the early stages of secondary succession

To study secondary successional sequences and mechanisms, denudation experiments were conducted in Central Japan with the removal of dominants, laying burned soil on the surface, and turning over the top- and subsoil. The early stages of secondary succession were predictable as to species and life-form composition.

C10-polyacetylenes as allelopathic substances in dominants in early stages of secondary succession

cis-Dehydromatricaria ester (cis-DME) inSolidago altissima, andcis-matricaria ester (cis-ME),trans-matricaria ester (trans-ME), andcis-lachnophyllum ester (cis-LE) inErigeron spp. show strong growth inhibitory effects on other plants. Thecis- andtrans-DMEs were found in soil at the border ofS. altissima communities in concentrations that were inhibitory to test plants. Among four species ofErigeron, the most dominant plant,E floribundus, showed the highest concentrations of the esters. From the results of our experiments, we conclude that these polyacetylenes are probably allelopathic substances with ecological importance.

A comparison of mature with recently clear-cut and scarified lodgepole pine forests in the Lower Foothills of Alberta

Mature, even-aged lodgepole pine (Pinuscontorta Dougl. var latifolia Engelm.) forests on upland sites with Orthic Gray Luvisols in the Lower Foothills of Alberta have been clear-cut for pulpwood and scarified by bulldozer since 1958. Undisturbed stands had weak shrub strata, well developed herb – dwarf shrub strata, and continuous feather moss strata.In 25 clear-cut stands 6–12 years old, the average cover of vascular plants was 54% and did not change significantly during the sampled age interval. Cover of tree 'regeneration' (immature size classes) was 5%, increasing slowly, and codominated by lodgepole pine and aspen (Populustremuloides Michx.). Shrub cover was also 5% and dominated by prickly rose (Rosaacicularis Lindl.). Herb – dwarf shrub cover was 44% and dominated by nine species of the mature forest. Bryoid cover was 13 %.The density of young trees stabilized within 6 years after clear-cutting, and the above-ground biomass of both pine and aspen increased rapidly during the sampled age interval.An ordination of the clear-cut stands showed that the distribution and abundance of several important plant species were well correlated with soil moisture on two gravimetric sampling dates in summer.A comparison of dominance–diversity curves and indices for mature and clear-cut stands revealed that the clear-cut community was richer in vascular species (100 cf. 57) and had a more even distribution of cover among species.The early stages of secondary succession after clear-cutting and scarification of lodgepole pine forest are discussed.