scholarly journals Ecological Biogeography of West Usambara Mountains: A Study on the Influence of Abiotic Factors to Spatial Distribution of Plant and Animal Species

Author(s):  
Joel Loitu Meliyo ◽  
Kenneth F.G. Masuki ◽  
Balthazar M. Msanya ◽  
Didas N. Kimaro ◽  
Loth S. Mulungu

1995 ◽  
pp. 3-21
Author(s):  
S. S. Kholod

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).



2001 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Sylvie Thurnheer ◽  
Heinz-Ulrich Reyer

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.



2020 ◽  
Vol 9 (3) ◽  
pp. 93-99
Author(s):  
Nazar N. Nazarenko ◽  
Aleksandr V. Malaev ◽  
Alla V. Pirozhenkova ◽  
Natalya A. Bayda

The patterns (mosaicity) in steppe meadow vegetation were characterized at the border of Forest-steppe and Steppe zones of the Southern Ural by hierarchical continuum concept theory for Troitskiy state natural complex preserve example. It has been established that the discordant natural region bring about mosaicity destruction micro-patterns are fuzzy, parcels are not formed and coenotics (12,0 m) level is identified only. The steppe meadow vegetation is characterized by coenotic level continuum coenotic patterns have almost identical dominant and co-dominant species composition, phytochorologic units form combination of four meadow grasses with middle and weak contagious spatial distribution and most species have random spatial distribution. But the steppe meadow biotopes are characterized by specifics of abiotic factors. The significant factors, influencing coenotic patterns and biotopes of steppe meadow, are soil calcium and nitrogen regime, soil aeration, moistening and its variability.



bionature ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Muhammad Richsan Yamin ◽  
Siti Annisaa'ul Kariimah ◽  
Nadya Rizky Nuzul Ramadhanti ◽  
Intan Ayu Idha Wulandari

Abstract. The purpose of this research were to (1) analyse the temporal and spatial distribution of arthropods in the cassava and eggplant agroecosystem areas. (2) Analysing the temporal and spatial distribution of arthropods in the maize agroecosystem. This research was divided into 2 stations,  the first station which is near the trail in the eggplant and corn agroecosystem, while for the second station on the corn agroecosystem, the two research locations are in Maccorawalie Village, Watang Sawitto District, Pinrang Regency, South Sulawesi. This research use the analytical method to analyse the observations and also identify the families of each arthropod found, then count the number of arthropods in each species and measure the diversity and abundance of each wild plant found at station 1 and station 2 in the morning and afternoon. The translation of the results obtained from the results of data collection at two stations in two data collection times (morning and afternoon) in the day, where the morning is 06.00-8.00 WITA Zone, while in the afternoon at 16.00-17.30 WITA zone. This is due to abiotic factors such as temperature and humidity, where the temperature in the morning is 23°C with 92% humidity, while the afternoon temperature is 25°C with 77% humidity. Arthropods have a different temporal distribution because this is related to the biological clock in each Arthropod. Biological clock allows Arthropods to determine when to work and rest. The existence of a rhythm in insects resulted in the division of two living groups, known as diurnal (active during the day) and nocturnal. Abiotic factors in the form of light intensity, temperature and humidity, affect the activity patterns of insects that have a certain temperature range, light intensity and humidity in Maccorawalie Village, Watang Sawitto District, Pinrang Regency.Keywords: temporal distribution, spatial distribution, arthropods, agroecosystem.



2018 ◽  
Author(s):  
John H. Boyle ◽  
Dino Martins ◽  
Paul M. Musili ◽  
Naomi E. Pierce

AbstractThe association between the African ant plant, Vachellia drepanolobium, and the ants that inhabit it has provided insight into the boundaries between mutualism and parasitism, the response of symbioses to environmental perturbations, and the ecology of species coexistence. We use a landscape genomics approach at sites sampled throughout the range of this system in Kenya to investigate the demographics and genetic structure of the different partners in the association. We find that different species of ant associates of V. drepanolobium show striking differences in their spatial distribution throughout Kenya, and these differences are only partly correlated with abiotic factors. A comparison of the population structure of the host plant and its three obligately arboreal ant symbionts, Crematogaster mimosae, Crematogaster nigriceps, and Tetraponera penzigi, shows that the ants exhibit somewhat similar patterns of structure throughout each of their respective ranges, but that this does not correlate in any clear way with the respective genetic structure of the populations of their host plants. A lack of evidence for local coadaptation in this system suggests that all partners have evolved to cope with a wide variety of biotic and abiotic conditions.



2019 ◽  
Vol 11 (14) ◽  
pp. 186 ◽  
Author(s):  
Lucas Faro Bastos ◽  
Artur Vinícius Ferreira dos Santos ◽  
Fernanda Valente Penner ◽  
Lizandra Maria Maciel Siqueira ◽  
Anderson Gonçalves da Silva ◽  
...  

Haplaxius crudus is the primary vector of the phytoplasma that causes the Lethal Yellowing of Coconut, a disease that has become a barrier to the establishment of large coconut plantations in the world. The objective of this study was to determine the spatial distribution pattern and population dynamics of H. crudus adults by correlating them with the abiotic factors, such as temperature and rainfall in commercial dwarf coconut palm plantations. Collection of American palm cixiid was carried out using yellow sticky traps fixed to the abaxial part of the coconut leaves. The sampled plants were georeferenced to obtain the geographic coordinates and geostatistical analysis, besides the planialtimetric survey of the experimental plot for the preparation of the map that shows the topographic conformation of the terrain. Insects were found at the study site throughout the year, showing greater abundance in months when the average monthly temperatures and rainfall were not significant. The climatic factors showed a correlation with the total of insects, positive for the temperature, with 0.733 and negative for the precipitation with -0.606. The spatial distribution of H. crudus displayed an aggregate pattern, explained by the spherical model. The infestation focus occurred in the periphery of the plot, near a Brachiaria humidicola pasture. It was concluded that the infestation of the H. crudus showed a behavior directly related to the local climatic conditions and the aggregate spatial distribution explained by the spherical model, therefore, forming shrubs with a radius of 154 to 190 m, with areas of influence between 7.45 and 17.80 ha, which coincide with the lower part of the terrain.



2019 ◽  
Vol 76 (1) ◽  
pp. 115-118
Author(s):  
Milton A. N. Ortuño ◽  
Alonso E. Machtig ◽  
Martín A. Chacón ◽  
Jael Cuzmar ◽  
Francisco E. Fontúrbel


Author(s):  
Yibo Wang ◽  
Wenjing Zhang ◽  
Yuanshao Lin ◽  
Lianming Zheng ◽  
Wenqing Cao ◽  
...  

AbstractIn this study, the spatial distribution and seasonal variation of large tintinnids (>76 μm) were investigated in Shenhu Bay during three seasons of 2012. Of the 36 species identified, 9 were dominant (i.e. Tintinnopsis radix, Leprotintinnus simplex, Tintinnopsis japonica, Tintinnopsis tubulosoides, Leprotintinnus nordqvisti, Tintinnopsis beroidea, Stenosemella parvicollis, Tintinnidium primitivum, Tintinnopsis nana). A clear seasonal shift of the taxonomic composition as well as the lorica size of the dominant species was observed. The highest numbers of tintinnid species occurred in spring, while the highest abundance and biomass occurred in summer. Clustering indicated that the seasonal variations of the community structure were more obvious than spatial variations. Spearman correlation analysis revealed that density of phytoplankton prey had a significant impact on the tintinnid abundance. Redundancy analysis (RDA) illustrated that temperature, salinity and the nutrient level were the most important abiotic factors affecting the spatial and seasonal pattern of tintinnid communities in Shenhu Bay.



Author(s):  
Gabriel L. Bochini ◽  
Adilson Fransozo ◽  
Antonio L. Castilho ◽  
Gustavo L. Hirose ◽  
Rogerio C. Costa

The goal of the present study was to assess the temporal and spatial distribution of L. schmitti in three bays of the northern coast of the State of São Paulo, Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV), over a period of two years (1998 and 1999). Abiotic factors were monitored to test their influence on the distribution of the species through redundancy analysis. The shrimp were captured using a commercial fishing boat equipped with double-rig trawling nets at six sampling points. A total of 5658 individuals were collected during the study (4437 and 1221 in the first and second years, respectively). The number of individuals differed between years, bays, seasons and sampling locations. The highest number of L. schmitti was collected in MV (N = 2747), followed by UBM (N = 1649) and UBA (N = 1262). Shrimp abundance correlated positively with organic matter content, salinity and temperature, with the highest number of individuals collected from sites with intermediate levels of organic content (4 and 6%) and increasing when the sediment had a higher proportion of fine and very fine sand + clay. Abundance was also associated negatively with rainfall, given that the analysed population showed a seasonal pattern, with an increase in capture rate in those months following the rainy season. Average rainfall was 222.47 ± 138.68 mm, with a maximum of 538 mm and a minimum of 22.4 mm. The results obtained in this study suggest that, in the region of Ubatuba, temperature, salinity, organic content and rainfall modulate the distribution of these animals.



2016 ◽  
Vol 3 ◽  
Author(s):  
Ciércoles Cristina ◽  
García-Ruiz Cristina ◽  
González Maria ◽  
López-González Nieves ◽  
Tuite Patrick ◽  
...  


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