scholarly journals The effects of successional stage and size of gaps on recruitment of clonal plants in overgrowing Molinietum caeruleae meadows

2014 ◽  
Vol 67 (4) ◽  
pp. 87-98 ◽  
Author(s):  
Kinga Kostrakiewicz-Gierałt
Keyword(s):  
Seedling Recruitment ◽  
Abiotic Factors ◽  
Negative Relationship ◽  
Clonal Plants ◽  
Plant Canopy ◽  
Lateral Growth ◽  
Successional Stage ◽  
Closed Canopy ◽  
Successional Stages ◽  
Almost All

<p>In majority of plant communities with a closed canopy, the disturbances created by abiotic factors and biotic agents contribute to origin of an area free of existing vegetation and considered as safe sites for seedling recruitment. Although the gaps are characterized by several features, the size is proposed to be the most important characteristic. The investigations of recruitment of clonal taxa in different–sized gaps were conducted in the years 2011–2012 in <em>Molinietum caeruleae</em> meadows representing various successional stages and dominated by different species. Patch ES, representing early-successional stage, was dominated by small meadow species, Patch MS, representing mid-successional stage, was prevailed by tall-growing macroforbs, while Patch LS representing late-successional stage was overgrown by macroforbs and willows. In the successive sites the mean height of plant canopy, as well as the period of spring inundation increased gradually.</p><p>The total number of species and seedlings decreased from the Patch ES, through the Patch MS, to the Patch LS. Almost all plants presenting positive correlation between seedling number and gap area created hypogeogenous stems with substantial lateral growth and considerable number of short-lived daughter ramets allowing the fast colonization of neighbourhood. The majority of species showing negative relationship formed epigeogenous stems with slight lateral growth, as well as low number of long-lived ramets contributing to slow colonization of area.</p><p>In light of performed studies, it might be concluded, that making disturbance in continuous plant canopy and litter might be very effective way of conservation of <em>Molinietum caeruleae</em> meadows. The creation of different-sized gaps seems to be especially valuable due to the maintenance of heterogeneity of clonal species, which is particularly important in advanced successional stages.</p>

scholarly journals Closed-Canopy Tropical Forests of Hainan, (China) Are Resilient against Invasive Herbs and Shrubs

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1596
Author(s):  
Xiaobo Yang ◽  
Long Li ◽  
Xiaobo Lv ◽  
Wenqi Luo ◽  
Donghai Li ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Invasive Plants ◽  
Native Species ◽  
Invasive Plant ◽  
Soil Seed Bank ◽  
Light Availability ◽  
Successional Stage ◽  
Sharp Drop ◽  
Closed Canopy ◽  
Successional Stages

The successful establishment of many plants in tropical forests often depends on species-specific adaptations related to light availability and forest successional stage. Species that are present in early successional stages generally do not occur in later successional stages. In this study, we documented the diversity, distribution, and abundance of terrestrial invasive plants across the (sub)tropical island of Hainan, China, and tested the germination of specific invasive plants in forested environments. In 97 transects positioned randomly across the island, we found nine invasive herb and shrub species were present in all human-modified habitats but not in intact forest interiors. In separate forest-specific transects, we documented a sharp drop in the abundance of invasive plants >5 m into the forest. High numbers of invasive plant seeds germinated from the soil seed bank sampled at the forest edge, but very few seeds germinated from soil sampled any distance into the forest. Finally, in experiments with four focal invasive plant species, overall germination rates were low; and much lower in shaded sites compared to full gap sites. In conclusion, our findings demonstrated that invasive herbs and shrubs do not yet form a serious threat to native species in the closed-canopy forests of Hainan.

The species evenness of “prey” bacteria correlated with Bdellovibrio-and-like-organisms (BALOs) in the microbial network supports the biomass of BALOs in a paddy soil

2020 ◽  
Vol 96 (12) ◽  
Author(s):  
Hang Qian ◽  
Chunli Hou ◽  
Hao Liao ◽  
Li Wang ◽  
Shun Han ◽  
...  
Keyword(s):  
Soil Properties ◽  
Paddy Soil ◽  
High Throughput Sequencing ◽  
Abiotic Factors ◽  
Negative Relationship ◽  
Sequencing Analysis ◽  
Nitrogen Use ◽  
Microbial Network ◽  
Α Diversity ◽  
Positive Effect

ABSTRACT To seek how soil biotic and abiotic factors which might shape the Bdellovibrio-and-like-organisms community, we sampled paddy soils under different fertilization treatments including fertilization without nitrogen (Control), the nitrogen use treatment (N) and the nitrogen overuse one (HNK) at three rice growing stages. The abundances of BALOs were impacted by the rice-growing stages but not the fertilization treatments. The abundances of Bdellovibrionaceae-like were positively associated with soil moisture, which showed a negative relationship with Bacteriovoracaceae-like bacteria. High-throughput sequencing analysis of the whole bacterial community revealed that the α-diversity of BALOs was not correlated with any soil properties data. Network analysis detected eight families directly linked to BALOs, namely, Pseudomonadaceae, Peptostreptococcaceae, Flavobacteriaceae, Sediment-4, Verrucomicrobiaceae, OM27, Solirubrobacteraceae and Roseiflexaceae. The richness and composition of OTUs in the eight families were correlated with different soil properties, while the evenness of them had a positive effect on the predicted BALO biomass. These results highlighted that the bottom-up control of BALOs in paddy soil at least partially relied on the changes of soil water content and the diversity of bacteria directly linked to BALOs in the microbial network.

scholarly journals SOIL SEED BANK IN SEASONAL SEMIDECIDUOUS FOREST AND ABANDONED PASTURE

2016 ◽  
Vol 40 (6) ◽  
pp. 991-1001 ◽  
Author(s):  
Sustanis Horn Kunz ◽  
Sebastião Venâncio Martins
Keyword(s):  
Seed Bank ◽  
Soil Seed Bank ◽  
Life Forms ◽  
Successional Stage ◽  
Semideciduous Forest ◽  
Regeneration Stage ◽  
Significant Difference ◽  
Successional Stages ◽  
Pasture Area ◽  
Seasonal Semideciduous Forest

ABSTRACT The objective of this study was to characterize the seed bank in the soil of different successional stages of Seasonal Semideciduous Forest and abandoned pasture in order to understand the natural regeneration potential of these areas. At each successional stage, 30 samples of soil were collected in the rainy and dry seasons to evaluate the qualitative heterogeneity of the forest, at the regeneration stage (FEA) forest, intermediate regeneration stage forest (ISF) and pasture (PAS). The species were classified according to the life form, successional group and dispersion syndrome. The number of individuals germinated was significantly higher (p < 0.001) in the ISF and in the rainy season (15,949 individuals). Richness was higher in the pasture area (79 species), with a significant difference only between the environments. Most species are herbaceous (49.5%), pioneers (76.5%) and zoocory was the main dispersion syndrome (49% of species). The results show that seed bank in the fragment of the regeneration advanced stage forest presents the highest resilience potential, since it is formed by different life forms and, mainly, by early and late secondary species.

Problems of placing boundaries on ecological continua - options for a workable national rainforest definition in Australia

2000 ◽  
Vol 48 (4) ◽  
pp. 511 ◽  
Author(s):  
A. J. J. Lynch ◽  
V. J. Neldner
Keyword(s):  
Developmental Stages ◽  
Vegetation Type ◽  
Conservation Strategy ◽  
Mixed Forests ◽  
Minimal Component ◽  
Closed Canopy ◽  
Successional Stages ◽  
National Perspective ◽  
Definition Of ◽  
Floristic Characteristics

Options for a new definition of, and key for, rainforest in Australia are provided. The definitions take a national perspective, and are based on the ecological characteristics of rainforest species and some structural and floristic characteristics. Rainforest plant species are defined as those adapted to regenerating under low-light conditions experienced under the closed canopy or in localised gaps caused by recurring disturbances which are part of the natural rainforest ecosystem, and are not dependent on fire for successful regeneration. Three definitions are provided which differ in the extent of inclusion of transitional and seral communities. The first definition recognises communities such as mixed forests as transitional to rainforests and therefore as separate communities. The second definition includes a minimal component of emergent non-rainforest species in rainforest in the recognition that the main floristic component and functioning of the communities cannot be distinguished. The third definition includes the late successional stages of transitional and seral communities in rainforest on the presumption that such communities include non-rainforest species which are close to senescence, and that these communities are essential for the long-term conservation of rainforest in areas where rainforest is vulnerable and subject to major disturbance, particularly by fire. The first definition is concluded to be the least ambiguous and arbitrary, and enables a consistent approach to rainforest management. Recognition of mixed forests as a distinctive and mappable vegetation type should be incorporated in a comprehensive conservation strategy inclusive of all ecosystem developmental stages.

scholarly journals Biogeomorphic feedbacks and the ecosystem engineering of recently deglaciated terrain

2018 ◽  
Vol 43 (1) ◽  
pp. 24-45 ◽  
Author(s):  
Hannah R Miller ◽  
Stuart N Lane
Keyword(s):  
Environmental Stress ◽  
Ecosystem Engineer ◽  
Abiotic Factors ◽  
Ecosystem Engineering ◽  
Soil Development ◽  
Water Dynamics ◽  
Biotic Factors ◽  
Successional Stage ◽  
Abiotic And Biotic Factors

Matthews’ 1992 geoecological model of vegetation succession within glacial forefields describes how following deglaciation the landscape evolves over time as the result of both biotic and abiotic factors, with the importance of each depending on the level of environmental stress within the system. We focus in this paper on how new understandings of abiotic factors and the potential for biogeomorphic feedbacks between abiotic and biotic factors makes further development of this model important. Disturbance and water dynamics are two abiotic factors that have been shown to create stress gradients that can drive early ecosystem succession. The subsequent establishment of microbial communities and vegetation can then result in biogeomorphic feedbacks via ecosystem engineering that influence the role of disturbance and water dynamics within the system. Microbes can act as ecosystem engineers by supplying nutrients (via remineralization of organic matter and nitrogen fixation), enhancing soil development, either decreasing (encouraging weathering) or increasing (binding sediment grains) geomorphic stability, and helping retain soil moisture. Vegetation can act as an ecosystem engineer by fixing nitrogen, enhancing soil development, modifying microbial community structure, creating seed banks, and increasing geomorphic stability. The feedbacks between vegetation and water dynamics in glacial forefields are still poorly studied. We propose a synthesized model of ecosystem succession within glacial forefields that combines Matthews’ initial geoecological model and Corenblit's model to illustrate how gradients in environmental stress combined with successional time drive the balance between abiotic and biotic factors and ultimately determine the successional stage and potential for biogeomorphic feedbacks.

scholarly journals Forfeiting the founder effect: turnover defines biofilm community succession

2018 ◽  
Author(s):  
Colin J. Brislawn ◽  
Emily B. Graham ◽  
Karl Dana ◽  
Peter Ihardt ◽  
Sarah J. Fansler ◽  
...  
Keyword(s):  
Bacterial Colonization ◽  
Amplicon Sequencing ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Community Succession ◽  
Ecological Processes ◽  
Functional Capabilities ◽  
Resolution Imaging ◽  
Successional Stages ◽  
Almost All

ABSTRACTMicrobial community succession is a fundamental process that effects underlying functions of almost all ecosystems; yet the roles and fates of the most abundant colonizers are poorly understood. Does early abundance spur long term persistence? How do deterministic and stochastic processes influence the roles of founder species? We performed a succession experiment within a hypersaline microbial mat ecosystem to investigate how ecological processes contributed to the turnover of founder species. Bacterial and micro-eukaryotic founder species were identified from primary succession and tracked through a defined maturation period using 16S and 18S rRNA gene amplicon sequencing in combination with high resolution imaging that utilized stable isotope tracers to evaluate basic functional capabilities. The majority of the founder species did not maintain high relative abundances in later stages of succession. Turnover (versus nestedness) was the dominant process shaping the final community structure. We also asked if different ecological processes acted on bacteria versus eukaryotes during successional stages and found that deterministic and stochastic forces corresponded more with eukaryote and bacterial colonization, respectively. Our results show that taxa from different kingdoms, that share habitat in the tight spatial confines of a biofilm, were influenced by different ecological forces and time scales of succession.

scholarly journals The value of trophic interactions for ecosystem function: dung beetle communities influence seed burial and seedling recruitment in tropical forests

2016 ◽  
Vol 283 (1844) ◽  
pp. 20161634 ◽  
Author(s):  
Hannah M. Griffiths ◽  
Richard D. Bardgett ◽  
Julio Louzada ◽  
Jos Barlow
Keyword(s):  
Tropical Forests ◽  
Seedling Recruitment ◽  
Anthropogenic Impacts ◽  
Anthropogenic Activities ◽  
Seedling Emergence ◽  
Negative Relationship ◽  
Dung Beetle ◽  
Burial Depth ◽  
Seed Burial ◽  
Emergence Success

Anthropogenic activities are causing species extinctions, raising concerns about the consequences of changing biological communities for ecosystem functioning. To address this, we investigated how dung beetle communities influence seed burial and seedling recruitment in the Brazilian Amazon. First, we conducted a burial and retrieval experiment using seed mimics. We found that dung beetle biomass had a stronger positive effect on the burial of large than small beads, suggesting that anthropogenic reductions in large-bodied beetles will have the greatest effect on the secondary dispersal of large-seeded plant species. Second, we established mesocosm experiments in which dung beetle communities buried Myrciaria dubia seeds to examine plant emergence and survival. Contrary to expectations, we found that beetle diversity and biomass negatively influenced seedling emergence, but positively affected the survival of seedlings that emerged. Finally, we conducted germination trials to establish the optimum burial depth of experimental seeds, revealing a negative relationship between burial depth and seedling emergence success. Our results provide novel evidence that seed burial by dung beetles may be detrimental for the emergence of some seed species. However, we also detected positive impacts of beetle activity on seedling recruitment, which are probably because of their influence on soil properties. Overall, this study provides new evidence that anthropogenic impacts on dung beetle communities could influence the structure of tropical forests; in particular, their capacity to regenerate and continue to provide valuable functions and services.

scholarly journals The importance of beech forests as reservoirs of moth diversity in Mediterranean Basin (Lepidoptera)

2018 ◽  
Vol 50 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Marco Infusino ◽  
Stefano Scalercio
Keyword(s):  
Community Structure ◽  
Mediterranean Basin ◽  
Beech Forests ◽  
Number Of Species ◽  
Maturation Stages ◽  
Genetic Level ◽  
European Distribution ◽  
Successional Stages ◽  
The Difference ◽  
Almost All

Study analyzes the macrolepidoptera assemblages in beech woodlands of the Orsomarso Mountains (Pollino National Park, Southern Italy) to assess the role of beech forests in preserving diversity in Mediterranean Basin. Research was run between 2015 and 2016 in 15 stands representative of the main successional stages of forest maturation, placed between 990 and 1,475 meters of elevation. Monthlybased sampling was performed using UV-LED light traps. A total of 33,957 individuals belonging to 410 species was collected. The community is rich and the most abundant and characteristic species (Eilema lurideola, Operophtera fagata, Campaea margaritata) are almost all trophically linked to broadleaves or lichens. The community structure appears fairly constant and recognizable in all stands over the two years of sampling. Young beech forests hosted the greatest number of species compared to other forest maturation stages, though the difference is small. The greatest differences in the community structure are found in the clearings, where generalist and/or related to the herbaceous layer species are mostly represented. Biogeographically widely distributed species prevail, 87% of them having European or Asian-European distribution. There are a number of species of faunistic interest, among which Perizoma juracolaria, Chelis maculosa, Tiliacea citrago, Poecilocampa populi, Triphosa dubitata, Sideridis reticulata, Nebula senectaria, including 13 Italian endemics such as Coenotephria antonii. Populations of many species show significant genetic diversities compared to other European populations. The Orsomarso Mountains beech forests represent an important biodiversity reservoir, even at the genetic level, and show a good degree of naturalness.

scholarly journals The influence of C<sub>3</sub> and C<sub>4</sub> vegetation on soil organic matter dynamics in contrasting semi-natural tropical ecosystems

2015 ◽  
Vol 12 (10) ◽  
pp. 8085-8130 ◽  
Author(s):  
G. Saiz ◽  
M. Bird ◽  
C. Wurster ◽  
C. A. Quesada ◽  
P. Ascough ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Depth ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Carbon Isotopic Composition ◽  
Precipitation Gradient ◽  
Tropical Ecosystems ◽  
Carbon Isotopic ◽  
Closed Canopy

Abstract. Variations in the carbon isotopic composition of soil organic matter (SOM) in bulk and fractionated samples were used to assess the influence of C3 and C4 vegetation on SOM dynamics in semi-natural tropical ecosystems sampled along a precipitation gradient in West Africa. Differential patterns in SOM dynamics in C3/C4 mixed ecosystems occurred at various spatial scales. Relative changes in C / N ratios between two contrasting SOM fractions were used to evaluate potential site-scale differences in SOM dynamics between C3- and C4-dominated locations. These differences were strongly controlled by soil texture across the precipitation gradient, with a function driven by bulk δ13C and sand content explaining 0.63 of the observed variability. The variation of δ13C with soil depth indicated a greater accumulation of C3-derived carbon with increasing precipitation, with this trend being also strongly dependant on soil characteristics. The influence of vegetation thickening on SOM dynamics was also assessed in two adjacent, but structurally contrasting, transitional ecosystems occurring on comparable soils to minimise confounding effects posed by climatic and edaphic factors. Radiocarbon analyses of sand-size aggregates yielded relatively short mean residence times (τ) even deep in the soil, while the most stable SOM fraction associated to silt and clay exhibited shorter τ in the savanna woodland than in the neighbouring forest stand. These results together with the vertical variation observed in δ13C values, strongly suggest that both ecosystems are undergoing a rapid transition towards denser closed canopy formations. However, vegetation thickening varied in intensity at each site and exerted contrasting effects on SOM dynamics. This study shows that the interdependence between biotic and abiotic factors ultimately determine whether SOM dynamics of C3- and C4-derived vegetation are at variance in ecosystems where both vegetation types coexist. The results highlight the far-reaching implications that vegetation thickening may have for the stability of deep SOM.

The effect of forest successional stage on seed removal of tropical rain forest tree species

2002 ◽  
Vol 18 (2) ◽  
pp. 261-274 ◽  
Author(s):  
Marielos Peña-Claros ◽  
Henneleen De Boo
Keyword(s):  
Tree Species ◽  
Removal Rate ◽  
Forest Tree ◽  
Primary Forest ◽  
Secondary Forests ◽  
Seed Removal ◽  
Successional Stage ◽  
Successional Stages ◽  
Agricultural Areas ◽  
Number Of Seeds

Seed removal was evaluated at the macro- and micro-habitat level in areas differing in successional stage in the Bolivian Amazon. The successional stages consisted of secondary forests of 2, 10 and 20 years old and primary forest. Seeds of nine tree species were artificially dispersed and the number of seeds removed was evaluated over 7 weeks. Several stand characteristics were measured at the sites where seeds were dispersed. Seed removal at the end of the experiment varied from 50 to 100% depending on the species, and from 74 to 90% depending on successional stage. In general, the removal rate decreased with an increase in age of successional stage. The seed removal rate was related to liana density and not to litter thickness. Different microhabitat characteristics explained the seed removal rate of four species but microhabitat characteristics did not explain the decrease in seed removal rate with an increase in forest age. The results support the idea that post-dispersal seed removal reduces the number of seeds available for germination, consequently playing an important role in the regeneration of abandoned agricultural areas.

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