scholarly journals Spatial distribution and survival rate of waterfrog tadpoles in relation to biotic and abiotic factors: a field experiment

2001 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Sylvie Thurnheer ◽  
Heinz-Ulrich Reyer
Keyword(s):  
Spatial Distribution ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Rana Esculenta ◽  
Natural Conditions ◽  
Major Purpose ◽  
Biotic And Abiotic Factors ◽  
Lab Experiments ◽  
Shallow Zone ◽  
Population And Community Dynamics

AbstractPredictions about population and community dynamics are usually based on lab experiments. Because the results are difficult to transfer to natural conditions, the major purpose of this study was to test the effects of biotic and abiotic factors on tadpole populations in a natural environment. We stocked six ponds, created the previous year, with known numbers of Rana esculenta and R. lessonae tadpoles and followed their development over several months. When compared among ponds, tadpole density correlated positively with the nitrate:phosphate ratio. This suggests that water chemistry may have affected survival, either directly or indirectly via productivity. Within ponds, both species showed a clear preference for the shallow zone. This behavior probably reflects a preference for warm water close to the surface, rather than avoidance of predators, because relative densities of odonates also increased from deep to shallow zones. This study is one of few that not only considers the distribution of the anuran tadpoles but the distribution of their predators as well.

Biotic and abiotic factors affecting seasonal and spatial distribution of meiofauna and macrophytobenthos in transitional coastal waters

2019 ◽  
Vol 219 ◽  
pp. 328-340 ◽  
Author(s):  
Federica Semprucci ◽  
Chiara Facca ◽  
Federica Ferrigno ◽  
Maria Balsamo ◽  
Adriano Sfriso ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Coastal Waters ◽  
Abiotic Factors ◽  
Factors Affecting ◽  
Biotic And Abiotic Factors

Consequences of rainfall variation for breeding wetland blackbirds

2004 ◽  
Vol 82 (8) ◽  
pp. 1316-1325 ◽  
Author(s):  
Robert J Fletcher, Jr. ◽  
Rolf R Koford
Keyword(s):  
Clutch Size ◽  
Nest Predation ◽  
Community Dynamics ◽  
Prairie Pothole Region ◽  
Abiotic Factors ◽  
Reproductive Failure ◽  
Water Levels ◽  
Prairie Pothole ◽  
Rainfall Variation ◽  
Population And Community Dynamics

Annual variability in abiotic factors can be pronounced, especially in systems that rely on precipitation, such as arid regions and prairie potholes. We report how annual variation in precipitation from 1999 to 2002 in the Prairie Pothole Region of Iowa, USA, affected both density and reproduction of two interspecific competitors: yellow-headed blackbirds, Xanthocephalus xanthocephalus (Bonaparte, 1826), and red-winged blackbirds, Agelaius phoeniceus (L., 1766). During dry years, yellow-headed blackbirds, an obligate wetland-breeding species, showed a marked reduction in density and a complete reproductive failure in which none of the nests we monitored fledged young. The reproductive failure was attributed primarily to nest predation, which was negatively correlated with water levels in wetlands. Conversely, red-winged blackbirds, a facultative wetland-breeding species, showed little variation in density and nest success. Both species exhibited similar patterns of reduced clutch size and later nest initiation dates in dry years, measures often tied to bottom-up effects of food availability and (or) age of individuals. Yet top-down effects of nest predation had a stronger influence, because lower clutch size did not result in fewer young fledged per successful nest. Incorporating how rainfall variation can affect wetland songbird demography will be critical for understanding population and community dynamics in changing environments.

Large-scale mapping of the catenas vegetation in Subarctic tundra

1995 ◽  
pp. 3-21
Author(s):  
S. S. Kholod
Keyword(s):  
Spatial Distribution ◽  
Vegetation Cover ◽  
Large Scale ◽  
Block Diagram ◽  
Abiotic Factors ◽  
Ecological Factors ◽  
Spatial Arrangement ◽  
Geological Time ◽  
Ecological Barriers ◽  
Functional Zones

One of the most difficult tasks in large-scale vegetation mapping is the clarification of mechanisms of the internal integration of vegetation cover territorial units. Traditional way of searching such mechanisms is the study of ecological factors controlling the space heterogeneity of vegetation cover. In essence, this is autecological analysis of vegetation. We propose another way of searching the mechanisms of territorial integration of vegetation. It is connected with intracoenotic interrelation, in particular, with the changing role of edificator synusium in a community along the altitudinal gradient. This way of searching is illustrated in the model-plot in subarctic tundra of Central Chukotka. Our further suggestion concerns the way of depicting these mechanisms on large-scale vegetation map. As a model object we chose the catena, that is the landscape formation including all geomorphjc positions of a slope, joint by the process of moving the material down the slope. The process of peneplanation of a mountain system for a long geological time favours to the levelling the lower (accumulative) parts of slopes. The colonization of these parts of the slope by the vegetation variants, corresponding to the lowest part of catena is the result of peneplanation. Vegetation of this part of catena makes a certain biogeocoenotic work which is the levelling of the small infralandscape limits and of the boundaries in vegetation cover. This process we name as the continualization on catena. In this process the variants of vegetation in the lower part of catena are being broken into separate synusiums. This is the process of decumbation of layers described by V. B. Sochava. Up to the slope the edificator power of the shrub synusiums sharply decreases. Moss and herb synusium have "to seek" the habitats similar to those under the shrub canopy. The competition between the synusium arises resulting in arrangement of a certain spatial assemblage of vegetation cover elements. In such assemblage the position of each element is determined by both biotic (interrelation with other coenotic elements) and abiotic (presence of appropriate habitats) factors. Taking into account the biogeocoenotic character of the process of continualization on catena we name such spatial assemblage an exolutionary-biogeocoenotic series. The space within each evolutionary-biogeocoenotic series is divided by ecological barriers into some functional zones. In each of the such zones the struggle between synusiums has its individual expression and direction. In the start zone of catena (extensive pediment) the interrelations of synusiums and layers control the mutual spatial arrangement of these elements at the largest extent. Here, as a rule, there predominate edificator synusiums of low and dwarfshrubs. In the first order limit zone (the bend of pediment to the above part of the slope) one-species herb and moss synusiums, oftenly substituting each other in similar habitats, get prevalence. In the zone of active colonization of slope (denudation slope) the coenotic factor has the least role in the spatial distribution of the vegetation cover elements. In particular, phytocoenotic interactions take place only within separate microcoenoses of herbs, mosses and lichens. In the zone of the attenuation of continualization process (the upper most parts of slope, crests) phytocoenotic interactions are almost absent and the spatial distribution of vegetation cover elements depends exclusively on the abiotic factors. The principal scheme of the distribution of vegetation cover elements and the disposition of functional zones on catena are shown on block-diagram (fig. 1).

scholarly journals The Effects of Biotic and Abiotic Factors on the Community Dynamics in a Mountain Subtropical Forest

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 427
Author(s):  
Tianyang Zhou ◽  
Jiaxin Zhang ◽  
Yunzhi Qin ◽  
Mingxi Jiang ◽  
Xiujuan Qiao
Keyword(s):  
Climate Change ◽  
Ecosystem Services ◽  
Forest Dynamics ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Subtropical Forest ◽  
Above Ground Biomass ◽  
Short Term ◽  
Forest Ecosystem Services ◽  
Number Of Individuals

From supporting wood production to mitigating climate change, forest ecosystem services are crucial to the well-being of humans. Understanding the mechanisms that drive forest dynamics can help us infer how to maintain forest ecosystem services and how to improve predictions of forest dynamics under climate change. Despite the growing number of studies exploring above ground biomass (AGB) dynamics, questions of dynamics in biodiversity and in number of individuals still remain unclear. Here, we first explored the patterns of community dynamics in different aspects (i.e., AGB, density and biodiversity) based on short-term (five years) data from a 25-ha permanent plot in a subtropical forest in central China. Second, we examined the relationships between community dynamics and biodiversity and functional traits. Third, we identified the key factors affecting different aspects of community dynamics and quantified their relative contributions. We found that in the short term (five years), net above ground biomass change (ΔAGB) and biodiversity increased, while the number of individuals decreased. Resource-conservation traits enhanced the ΔAGB and reduced the loss in individuals, while the resource-acquisition traits had the opposite effect. Furthermore, the community structure contributed the most to ΔAGB; topographic variables and soil nutrients contributed the most to the number of individuals; demographic process contributed the most to biodiversity. Our results indicate that biotic factors mostly affected the community dynamics of ΔAGB and biodiversity, while the number of individuals was mainly shaped by abiotic factors. Our work highlighted that the factors influencing different aspects of community dynamics vary. Therefore, forest management practices should be formulated according to a specific protective purpose.

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