The influence of successional stage on local odonate communities in man-made standing waters

2021 ◽  
Vol 173 ◽  
pp. 106440
Author(s):  
Vojtech Kolar ◽  
Petr Vlašánek ◽  
David S. Boukal
2010 ◽  
Vol 40 (4) ◽  
pp. 788-795 ◽  
Author(s):  
Xu Wang ◽  
Yanling Jiang ◽  
Bingrui Jia ◽  
Fengyu Wang ◽  
Guangsheng Zhou

CO2 efflux from forest soils is an important process in the global carbon cycle; however, effects of stand age and successional status remain uncertain. We compared soil respiration and its relationship to soil carbon content, forest floor mass, root biomass, soil temperature, and soil moisture content among three temperate forest ecosystems in Changbai Mountains, northeastern China, from 2003 to 2005. Forest types included an old-growth, mixed coniferous and broad-leaved primary forest (MN), a middle-aged, broad-leaved secondary forest (BL), and a young coniferous plantation forest (CP). Average annual soil CO2 efflux at BL (1477.9 ± 61.8 g C·m–2·year–1) was significantly higher than at CP (830.7 ± 48.7 g C·m–2·year–1) and MN (935.4 ± 53.3 g C·m–2·year–1). Differences in soil temperature among those sites were not statistically significant but contributed to the differences in annual CO2 efflux. In addition, the temperature response of soil CO2 efflux was higher at MN (Q10 = 2.78) than that at BL (Q10 = 2.17) and CP (Q10 = 2.02). Our results suggest that successional stage affects soil respiration by the differences in substrate quantity and quality, environmental conditions, and root respiration.


2016 ◽  
Vol 40 (6) ◽  
pp. 991-1001 ◽  
Author(s):  
Sustanis Horn Kunz ◽  
Sebastião Venâncio Martins

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.


2007 ◽  
Vol 67 (3) ◽  
pp. 403-411 ◽  
Author(s):  
WG. Silva ◽  
JP. Metzger ◽  
S. Simões ◽  
C Simonetti

Several studies suggest that, on a large scale, relief conditions influence the Atlantic Forest cover. The aim of this work was to explore these relationships on a local scale, in Caucaia do Alto, on the Ibiúna Plateau. Within an area of about 78 km², the distribution of forest cover, divided into two successional stages, was associated with relief attribute data (slope, slope orientation and altitude). The mapping of the vegetation was based on the interpretation of stereoscopic pairs of aerial photographs, from April 2000, on a scale of 1:10,000, while the relief attributes were obtained by geoprocessing from digitalized topographic maps on a scale of 1:10,000. Statistical analyses, based on qui-square tests, revealed that there was a more extensive forest cover, irrespective of the successional stage, in steeper areas (>10 degrees) located at higher altitudes (>923 m), but no influence of the slope orientation. There was no sign of direct influence of relief on the forest cover through environmental gradients that might have contributed to the forest regeneration. Likewise, there was no evidence that these results could have been influenced by the distance from roads or urban areas or with respect to permanent preservation areas. Relief seems to influence the forest cover indirectly, since agricultural land use is preferably made in flatter and lower areas. These results suggest a general distribution pattern of the forest remnants, independent of the scale of study, on which relief indirectly has a strong influence, since it determines human occupation.


2018 ◽  
Vol 43 (1) ◽  
pp. 24-45 ◽  
Author(s):  
Hannah R Miller ◽  
Stuart N Lane

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.


2013 ◽  
Vol 10 (7) ◽  
pp. 11181-11211 ◽  
Author(s):  
N. Lu ◽  
J. Liski ◽  
R. Y. Chang ◽  
A. Akujärvi ◽  
X. Wu ◽  
...  

Abstract. Soil organic carbon (SOC) is the largest terrestrial carbon pool and sensitive to land use and cover change; its dynamics is critical for carbon cycling in terrestrial ecosystems and the atmosphere. In this study, we combined a modeling approach and field measurements to examine the temporal dynamics of SOC following afforestation of former arable land at six sites under different climatic conditions in the Loess Plateau during 1980–2010. The results showed that the measured mean SOC increased to levels higher than before afforestation when taking the last measurements (i.e., at age 25 to 30 yr), although it decreased in the first few years at the wetter sites. The accumulation rates of SOC were 1.58 to 6.22% yr–1 in the upper 20 cm and 1.62 to 5.15% yr–1 in the upper 40 cm of soil. The simulations reproduced the basic characteristics of measured SOC dynamics, suggesting that litter input and climatic factors (temperature and precipitation) were the major causes for SOC dynamics and the differences among the sites. They explained 88–96, 48–86 and 57–74% of the variations in annual SOC changes at the soil depths of 0–20, 0–40, and 0–100 cm, respectively. Notably, the simulated SOC decreased during the first few years at all the sites, although the magnitudes of decreases were small at the drier sites. This suggested that the modeling may be advantageous in capturing SOC changes at finer time scale. The discrepancy between the simulation and measurement was a result of uncertainties in model structure, data input, and sampling design. Our findings indicated that afforestation promoted soil carbon sequestration at the study sites, which is favorable for further restoration of the vegetation and environment. Afforestation activities should decrease soil disturbances to reduce carbon release in the early stage. The long-term strategy for carbon fixation capability of the plantations should also consider the climate and site conditions, species adaptability, and successional stage of recovery.


2009 ◽  
Vol 19 (2) ◽  
pp. 20-30
Author(s):  
Nguendo Yongsi H.B. ◽  
Ntetu Lutumba A. ◽  
Bryant R. Christopher ◽  
Ojuku Tiafack ◽  
Hermann Thora M.

Context: Like many sub Saharan African cities, Yaoundé is experiencing a faster growth of its population and urban perimeter. The urban population has grown from 812 000 inhabitants in 1987 to 2 100 000 inhabitants in 2006. However, this population growth has not been monitored by the city planners and decision makers. Accordingly, the city is lacking basic urban facilities. such as a good sewage system to evacuate urban waste water. Objective: This paper aims at addressing health consequences resulting from inadequate management of rainwater in Yaoundé. Material and methods: From the data gathered by us in the framework of the PERSAN programme focused on urban health, a cross sectional study has been carried out in 2002 and 2006 across the city. Based on socio-environmental and medical surveys, the study covered neighborhoods and 3 034 households in Yaoundé. Results: It comes out that that the present urban draining network is outdated and ineffective. This has led to increasing fl oods in several sectors of the city, with health hazards. It has been noted that many diarrheal diseases in Yaoundé are related to the poor sanitation resulting from urban waste coupled with standing waters. Conclusion: We are of the opinion that to solve this problem, there is urgent need to set up a new town-planning mechanism which takes into account the city’s demographic and space dynamics.


2001 ◽  
Vol 79 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Alexander R Cobb ◽  
Nalini M Nadkarni ◽  
Grant A Ramsey ◽  
Abraham J Svoboda

The dynamics of epiphytic bryophyte communities following natural and human disturbance have rarely been quantified. We describe the response of bryophyte communities on bigleaf maple trees (Acer macrophyllum Pursh) in Olympia, Washington, following their experimental removal. Approximately 8% of the exposed area was recolonized by bryophytes 1 year after clearing, and 27% after 3 years. Lateral encroachment from bryophytes on the sides of the 20-cm-long plots accounted for 75% of this recolonization, with growth from residual plant parts or aerially dispersed diaspores accounting for the remaining 25%. Though it was not possible to distinguish between the latter two sources of cover, the number of clear de novo colonization events over the course of the year was low (0.18 dm-2). Disturbance appeared to reduce bryophyte diversity at this successional stage, as alpha and gamma diversity remained low after 1 year and had not recovered after 3 years. Reflecting the preponderance of lateral encroachment as the mechanism for recolonization, disturbance size may significantly affect the time needed to recolonize disturbed branch substrates. In addition to contributing to ecologists' understanding of processes of succession, these experiments may help to develop sustainable practices for moss-harvesting in the Pacific Northwest.Key words: succession, bryophytes, epiphytes, Acer macrophyllum, recolonization, canopy studies.


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