scholarly journals The Large-Scale Spatial Patterns of Ecological Networks Between Phytoplankton and Zooplankton in Coastal Marine Ecosystems

2020 ◽  
Author(s):  
Zheng Zhang ◽  
Hongjun Li ◽  
Wenli Shen ◽  
Xiongfeng Du ◽  
Shuzhen Li ◽  
...  
Keyword(s):  
Spatial Pattern ◽  
Spatial Patterns ◽  
Species Interactions ◽  
Large Scale ◽  
Northern Region ◽  
Positive Interactions ◽  
Spatial Gradient ◽  
Turnover Rates ◽  
Spatial Gradients ◽  
The North

Abstract BackgroundThe marine autotrophic phytoplankton is responsible for approximately half of global primary production on Earth, and as the planktonic consumers, the heterotrophic zooplankton could link the phytoplankton and higher trophic level to complete the aquatic Food Web. Despite the interaction between phytoplankton and zooplankton has played important roles in speciation and ecosystem function, little is known about the spatial patterns of their interactions at the continental scale.ResultsHere, we collected 251 seawater samples along 13,000 km of Chinese coastline, and microscopically investigated the spatial gradient patterns of phytoplanktonic and zooplanktonic diversities. In total, 307 phytoplanktonic and 311 zooplanktonic species were visually identified. The distance-decay relationships showed higher turnover rates for zooplankton than phytoplankton, indicating zooplankton had more divergent compositions across larger distances. Furthermore, the zooplankton-phytoplankton interaction networks demonstrated more complex and numerous connections along the southern coast than in the north, suggesting the interactions between these two major planktonic groups had a geographic spatial pattern. The types of planktonic interactions changed along the latitudinal gradient, with positive interactions dominant in northern and middle regions, while the percentage of positive and negative interactions were approximately equal in the southern latitudinal region. Additionally, some particular association between zooplanktonic and phytoplanktonic groups were found to be localized in specific regions, such as autotrophic C. lorenzianus was only associated with heterotrophic Copepoda in northern region, and C. oculus-iridis was only associated with Copepoda and Chaetognatha in the middle (ECS) and southern (SCS) respectively.ConclusionsWe demonstrate here that not only the planktonic biodiversity and community structure exhibited a clear spatial pattern, but also the interaction between phytoplankton and zooplankton also changed with spatial variation. Our results provide a valuable ecological perspective to the biogeography patterns of coastal plankton along the large-scale spatial gradients, and have important implications for understanding how complex planktonic species interactions changed with location variation.

scholarly journals Geospatial Analysis of Extreme Weather Events in Nigeria (1985–2015) Using Self-Organizing Maps

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Adeoluwa Akande ◽  
Ana Cristina Costa ◽  
Jorge Mateu ◽  
Roberto Henriques
Keyword(s):  
Extreme Precipitation ◽  
Large Scale ◽  
Northern Region ◽  
Extreme Weather Events ◽  
Self Organizing Map ◽  
Spatial And Temporal Patterns ◽  
Self Organizing Maps ◽  
The North ◽  
Precipitation Regimes ◽  
Self Organizing

The explosion of data in the information age has provided an opportunity to explore the possibility of characterizing the climate patterns using data mining techniques. Nigeria has a unique tropical climate with two precipitation regimes: low precipitation in the north leading to aridity and desertification and high precipitation in parts of the southwest and southeast leading to large scale flooding. In this research, four indices have been used to characterize the intensity, frequency, and amount of rainfall over Nigeria. A type of Artificial Neural Network called the self-organizing map has been used to reduce the multiplicity of dimensions and produce four unique zones characterizing extreme precipitation conditions in Nigeria. This approach allowed for the assessment of spatial and temporal patterns in extreme precipitation in the last three decades. Precipitation properties in each cluster are discussed. The cluster closest to the Atlantic has high values of precipitation intensity, frequency, and duration, whereas the cluster closest to the Sahara Desert has low values. A significant increasing trend has been observed in the frequency of rainy days at the center of the northern region of Nigeria.

scholarly journals Space Pattern of Samudera Pasai Sultanate

2021 ◽  
Vol 1 (2) ◽  
pp. 94-103
Author(s):  
Rinaldi Mirsa ◽  
Muhammad Muhammad ◽  
Eri Saputra ◽  
Izzati Farhana
Keyword(s):  
Spatial Pattern ◽  
Middle Ages ◽  
Spatial Patterns ◽  
Spatial Arrangement ◽  
Phenomenological Approach ◽  
Historical Records ◽  
Archaeological Remains ◽  
The West ◽  
The North ◽  
Space Pattern

Samudera Pasai is one of the Islamic Sultanates in Indonesia which appeared in the Middle Ages or around 1267 AD. Evidence of the existence of the Sultanate of Samuedra Pasai in Indonesia is listed in the book Rihlah ilal-Masyriq (Wanderings to the East) written by Abu Abdullah Ibnu Batutha (1304 - 1368 AD), a Muslim adventurer who traveled to Samudera Pasai in 1345 AD. The spatial pattern of the Samudera Pasai Sultanate is no longer visible because there are no traces of archaeological remains in the form of any remaining buildings, except for the tombs of Sultanate figures and historical records of foreign adventurers who have explored the Samudera Pasai Sultanate. This record strengthens the evidence of the existence of the Samudera Pasai Sultanate. The methodology used in this case is a phenomenological approach and a historical approach, which are expected to approach optimal results in uncovering spatial patterns in the development of Islam. The spatial arrangement of the sultanate generally used the concept of catur gatra tungga, which was arranged in the form of: alun-alun (the square) as the center of space, markets to the north of the square, palaces to the south of the square, and mosques to the west of the square. The spatial arrangement then formed a spatial pattern that became the center of the Samudera Pasai Sultanate.

scholarly journals Comment on Pescott & Jitlal 2020: Failure to account for measurement error undermines their conclusion of a weak impact of nitrogen deposition on plant species richness

2020 ◽  
Author(s):  
SM Smart ◽  
CJ Stevens ◽  
SJ Tomlinson ◽  
LC Maskell ◽  
PA Henrys
Keyword(s):  
Species Richness ◽  
Measurement Error ◽  
Plant Species ◽  
Large Scale ◽  
Plant Species Richness ◽  
N Deposition ◽  
Spatial Gradient ◽  
Spatial Gradients ◽  
Deposition Effect ◽  
Time Substitution

AbstractEstimation of the impacts of atmospheric nitrogen (N) deposition on ecosystems and biodiversity is a research imperative. Analyses of large-scale spatial gradients, where an observed response is correlated with measured or modelled deposition, have been an important source of evidence. A number of problems beset this approach. For example, if responses are spatially aggregated then treating each location as statistically independent can lead to biased confidence intervals and a greater probably of false positive results.Using sophisticated methods that account for residual spatial autocorrelation Pescott & Jitlal (2020) re-analysed two large-scale spatial gradient datasets from Britain where modelled N deposition at 5×5km resolution had been previously correlated with species richness in small quadrats. They found that N deposition effects were weaker than previously demonstrated leading them to conclude that “..previous estimates of Ndep impacts on richness from space-for-time substitution studies are likely to have been over-estimated”. We use a simple simulation study to show that their conclusion is flawed. They failed to recognise that an influential fraction of the residual spatially structured variation could itself be attributable to N deposition. This arises because the covariate used was modelled N deposition at 5×5km resolution leaving open the possibility that measured or modelled N deposition at finer resolutions could explain more variance in the response. Explicitly treating this as spatially auto-correlated error ignores this possibility and leads directly to their unreliable conclusion. We further demonstrate the plausibility of this scenario by showing that significant variation in N deposition at the 1km square resolution is indeed averaged at 5×5km resolution.Further analyses are required to explore whether estimation of the size of the N deposition effect on plant species richness and other measures of biodiversity is indeed dependent on the accuracy and hence measurement error of the N deposition covariate. Until then the conclusions of Pescott & Jitlal (2020) should be considered premature and not proven.

scholarly journals Transition region of TEC enhancement phenomena during geomagnetically disturbed periods at mid-latitudes

2005 ◽  
Vol 23 (11) ◽  
pp. 3439-3450 ◽  
Author(s):  
K. Unnikrishnan ◽  
A. Saito ◽  
Y. Otsuka ◽  
M. Yamamoto ◽  
S. Fukao
Keyword(s):  
Large Scale ◽  
Northern Region ◽  
Neutral Wind ◽  
Low Latitude ◽  
Layer Height ◽  
The North ◽  
Latitude Region ◽  
Height Increase ◽  
Background Content

Abstract. Large-scale TEC perturbations/enhancements observed during the day sectors of major storm periods, 12-13 February 2000, 23 September 1999, 29 October 2003, and 21 November 2003, were studied using a high resolution GPS network over Japan. TEC enhancements described in the present study have large magnitudes (≥25×1016 electrons/m2) compared to the quiet-time values and long periods (≥120 min). The sequential manner of development and the propagation of these perturbations show that they are initiated at the northern region and propagate towards the southern region of Japan, with velocities >350 m/s. On 12 February 2000, remarkably high values of TEC and background content are observed at the southern region, compared to the north, because of the poleward expansion of the equatorial anomaly crest, which is characterized by strong latitudinal gradients near 35° N (26° N geomagnetically). When the TEC enhancements, initiating at the north, propagate through the region 39-34° N (30-25° N geomagnetically), they undergo transitions characterized by a severe decrease in amplitude of TEC enhancements. This may be due to their interaction with the higher background content of the expanded anomaly crest. However, at the low-latitude region, below 34° N, an increase in TEC is manifested as an enhanced ionization pattern (EIP). This could be due to the prompt penetration of the eastward electric field, which is evident from high values of the southward Interplanetary Magnetic Field component (IMF Bz) and AE index. The TEC perturbations observed on the other storm days also exhibit similar transitions, characterized by a decreasing magnitude of the perturbation component, at the region around 39-34° N. In addition to this, on the other storm days, at the low-latitude region, below 34° N, an increase in TEC (EIP feature) also indicates the repeatability of the above scenario. It is found that, the latitude and time at which the decrease in magnitude of the perturbation component/amplitude of the TEC enhancement are matching with the latitude and time of the appearance of the high background content. In the present study, on 12 February 2000, the F-layer height increases at Wakkanai and Kokubunji, by exhibiting a typical dispersion feature of LSTID, or passage of an equatorward surge, which is matching with the time of occurrence of the propagating TEC perturbation component. Similarly, on 29 October 2003, the increase in F-layer heights by more than 150km at Wakkanai and 90 km at Kokubunji around 18:00 JST, indicates the role of the equatorward neutral wind. On that day, TEC perturbation observed at the northern region, after 18:30 JST, which propagates towards south, could be caused mainly by the equatorward neutral wind, leading to an F-layer height increase. These observations imply the role of the equatorward neutral wind, which increases the F-layer height, by lifting the ionization to the regions of lower loss during daytime, when production is still taking place, which, in turn, increases the TEC values. Large-scale traveling ionospheric disturbances (LSTIDs) are considered as ionospheric manifestations of the passage of Atmospheric Gravity Waves (AGWs) that are generated at the high latitude by energy input from the magnetosphere to the low-latitude ionosphere. This study shows that large-scale TEC perturbations observed here are produced at the northern region due to the combined effects of the equatorward neutral wind, the subsequent F-layer height increase, and LSTIDs. When these perturbation components propagate through the region, 39-34° N, they undergo transitions characterised by a decrease in magnitude. Also, at the low-latitude region, below 34° N, an increase in the TEC exhibits EIP feature, due to the prompt penetration of the eastward electric field.

Large-scale spatial patterns of forest structural diversity

2008 ◽  
Vol 38 (3) ◽  
pp. 429-438 ◽  
Author(s):  
Ronald E. McRoberts ◽  
Susanne Winter ◽  
Gherardo Chirici ◽  
Elmar Hauk ◽  
Dieter R. Pelz ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Large Scale ◽  
Structural Diversity ◽  
Diversity Indices ◽  
The United States ◽  
Shannon Index ◽  
Tree Diameter ◽  
The North ◽  
Highly Correlated ◽  
Ecological Province

Forest structural diversity was estimated for an ecological province in the north-central region of the United States of America using data for nearly 350 000 trees observed on >12 000 forest inventory plots. Each plot was 672 m2 in area, and the sampling intensity was approximately 1 plot/2400 ha. Two indices were used for each of two commonly and accurately measured inventory variables: species count and the Shannon index for tree species and standard deviation and the Shannon index for tree diameter. The primary results of the study were fourfold: (i) ranges of spatial correlation for diversity indices were small, on the order of 5–10 km, (ii) high proportions of provincewide diversity were realized for circular areas with radii as small as 15 km, (iii) diversity for both species and diameter exhibited strong northwest to southeast spatial patterns, and (iv) plot-level α diameter diversity was highly correlated with mean plot-level tree diameter.

scholarly journals Above and belowground carbon stock in a tropical forest in Brazil

2020 ◽  
Vol 43 ◽  
pp. e48276
Author(s):  
Daniel Dantas ◽  
Marcela de Castro Nunes Santos Terra ◽  
Luiz Otávio Rodrigues Pinto ◽  
Natalino Calegario ◽  
Sabrina Mandarano Maciel
Keyword(s):  
Tropical Forest ◽  
Spatial Pattern ◽  
Spatial Patterns ◽  
Fine Roots ◽  
Carbon Stock ◽  
Census Data ◽  
Global Climate ◽  
Carbon Stocks ◽  
Spatial Gradient ◽  
Global Climate Changes

An increase in atmospheric CO2 levels and global climate changes have led to an increased focus on CO2 capture mechanisms. The in situ quantification and spatial patterns of forest carbon stocks can provide a better picture of the carbon cycle and a deeper understanding of the functions and services of forest ecosystems. This study aimed to determine the aboveground (tree trunks) and belowground (soil and fine roots, at four depths) carbon stocks in a tropical forest in Brazil and to evaluate the spatial patterns of carbon in the three different compartments and in the total stock. Census data from a semideciduous seasonal forest were used to estimate the aboveground carbon stock. The carbon stocks of soil and fine roots were sampled in 52 plots at depths of 0-20, 20-40, 40-60, and 60-80 cm, combined with the measured bulk density. The total estimated carbon stock was 267.52 Mg ha-1, of which 35.23% was in aboveground biomass, 63.22% in soil, and 1.54% in roots. In the soil, a spatial pattern of the carbon stock was repeated at all depths analyzed, with a reduction in the amount of carbon as the depth increased. The carbon stock of the trees followed the same spatial pattern as the soil, indicating a relationship between these variables. In the fine roots, the carbon stock decreased with increasing depth, but the spatial gradient did not follow the same pattern as the soil and trees, which indicated that the root carbon stock was most likely influenced by other factors.

scholarly journals Comment on Pescott & Jitlal 2020: Failure to account for measurement error undermines their conclusion of a weak impact of nitrogen deposition on plant species richness

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10632
Author(s):  
Simon M. Smart ◽  
Carly J. Stevens ◽  
Sam J. Tomlinson ◽  
Lindsay C. Maskell ◽  
Peter A. Henrys
Keyword(s):  
Species Richness ◽  
Measurement Error ◽  
Plant Species ◽  
Large Scale ◽  
Plant Species Richness ◽  
N Deposition ◽  
Spatial Gradient ◽  
Spatial Gradients ◽  
Deposition Effect ◽  
Time Substitution

Estimation of the impacts of atmospheric nitrogen (N) deposition on ecosystems and biodiversity is a research imperative. Analyses of large-scale spatial gradients, where an observed response is correlated with measured or modelled deposition, have been an important source of evidence. A number of problems beset this approach. For example, if responses are spatially aggregated then treating each location as statistically independent can lead to biased confidence intervals and a greater probably of false positive results. Using methods that account for residual spatial autocorrelation, Pescott & Jitlal (2020) re-analysed two large-scale spatial gradient datasets from Britain where modelled N deposition at 5 × 5 km resolution had been previously correlated with species richness in small quadrats. They found that N deposition effects were weaker than previously demonstrated leading them to conclude that “previous estimates of Ndep impacts on richness from space-for-time substitution studies are likely to have been over-estimated”. We use a simulation study to show that their conclusion is unreliable despite them recognising that an influential fraction of the residual spatially structured variation could itself be attributable to N deposition. This arises because the covariate used was modelled N deposition at 5 × 5 km resolution leaving open the possibility that measured or modelled N deposition at finer resolutions could explain more variance in the response. Explicitly treating this as spatially auto-correlated error ignores this possibility and leads directly to their unreliable conclusion. We further demonstrate the plausibility of this scenario by showing that significant variation in N deposition at the 1 km square resolution is indeed averaged at 5 × 5 km resolution. Further analyses are required to explore whether estimation of the size of the N deposition effect on plant species richness and other measures of biodiversity is indeed dependent on the accuracy and hence measurement error of the N deposition covariate. Until then the conclusions of Pescott & Jitlal (2020) should be considered premature.

Spatial pattern of invading Dendroctonus micans (Coleoptera: Scolytidae) populations in the United Kingdom

2003 ◽  
Vol 33 (4) ◽  
pp. 712-725 ◽  
Author(s):  
M Gilbert ◽  
N Fielding ◽  
H F Evans ◽  
J -C Grégoire
Keyword(s):  
Spatial Pattern ◽  
Large Scale ◽  
Spatial Regression ◽  
Regional Scale ◽  
Management Control ◽  
Control Measures ◽  
Spatial Gradient ◽  
Dendroctonus Micans ◽  
Ecological Processes ◽  
Using Data

The spatial pattern of Dendroctonus micans (Kug.) attacks on individual spruce stands was analysed at the regional scale in Britain using data collected between 1982 and 1984 by the British Forestry Commission. These survey data reflect at least 10 years of D. micans spread, in the absence of natural enemies and of pest management control measures. A large-scale spatial gradient in the attack density at the stand level was identified and modelled. The large-scale spatial trend model explained 31.3% of the variability, and divided the study area in three separate areas: a zone where the insect was well established and where attack density presented low variations, a transition zone where attack density sharply decreased, and a zone not yet colonized. Attack density was related to site and stand factors, and to landscape neighbourhood in a linear spatial regression model. The factors correlated to attack density and the spatial autocorrelation structure of remaining variability were found to vary according to the zones, reflecting the predominance of different ecological processes occurring in colonized and uncolonized areas. The shape and orientation of the large-scale spatial model was shown to be mostly influenced by the spatial distribution of early attacks.

scholarly journals Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea

2009 ◽  
Vol 67 (2) ◽  
pp. 278-293 ◽  
Author(s):  
Henning Reiss ◽  
Steven Degraer ◽  
Gerard C. A. Duineveld ◽  
Ingrid Kröncke ◽  
John Aldridge ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
North Sea ◽  
Ecosystem Management ◽  
Large Scale ◽  
Fish Communities ◽  
Demersal Fish ◽  
Environmental Drivers ◽  
The North ◽  
Oyster Ground ◽  
The North Sea

Abstract Reiss, H., Degraer, S., Duineveld, G. C. A., Kröncke, I., Aldridge, J., Craeymeersch, J., Eggleton, J. D., Hillewaert, H., Lavaleye, M. S. S., Moll, A., Pohlmann, T., Rachor, E., Robertson, M., vanden Berghe, E., van Hoey, G., and Rees, H. L. 2010. Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea. – ICES Journal of Marine Science, 67: 278–293. Understanding the structure and interrelationships of North Sea benthic invertebrate and fish communities and their underlying environmental drivers is an important prerequisite for conservation and spatial ecosystem management on scales relevant to ecological processes. Datasets of North Sea infauna, epifauna, and demersal fish (1999–2002) were compiled and analysed to (i) identify and compare spatial patterns in community structure, and (ii) relate these to environmental variables. The multivariate analyses revealed significantly similar large-scale patterns in all three components with major distinctions between a southern community (Oyster Ground and German Bight), an eastern Channel and southern coastal community, and at least one northern community (>50 m deep). In contrast, species diversity patterns differed between the components with a diversity gradient for infauna and epifauna decreasing from north to south, and diversity hotspots of demersal fish, e.g. near the major inflows of Atlantic water. The large-scale hydrodynamic variables were the main drivers for the structuring of communities, whereas sediment characteristics appeared to be less influential, even for the infauna communities. The delineation of ecologically meaningful ecosystem management units in the North Sea might be based on the structure of the main faunal ecosystem components.

scholarly journals Meta-Analysis of Salmon Trophic Ecology Reveals Spatial and Interspecies Dynamics Across the North Pacific Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Caroline Graham ◽  
Evgeny A. Pakhomov ◽  
Brian P. V. Hunt
Keyword(s):  
Spatial Patterns ◽  
North Pacific ◽  
Large Scale ◽  
Prey Availability ◽  
Gulf Of Alaska ◽  
Marine Ecology ◽  
Niche Width ◽  
Fine Scale ◽  
The North ◽  
The North Pacific

We examined spatial patterns in diet, trophic niche width and niche overlap for chum, pink and sockeye salmon across the North Pacific during 1959–1969. This is a baseline period before major hatchery enhancement occurred coinciding with a negative phase of the Pacific Decadal Oscillation. Large-scale (between regions) and fine-scale (within regions) spatial and interspecies differences were apparent. In the Western Subarctic, all species tended to consume zooplankton. In the Bering Sea, chum consumed zooplankton, while sockeye and pink alternated between zooplankton and micronekton. In the Gulf of Alaska/Eastern Subarctic, chum and sockeye specialized on gelatinous zooplankton and cephalopod prey, respectively, while pink consumed a mixture of zooplankton and micronekton. The highest diet overlap across the North Pacific was between pink and sockeye (46.6%), followed by chum and pink (31.8%), and chum and sockeye (30.9%). Greater diet specialization was evident in the Gulf of Alaska/Eastern Subarctic compared to the Western Pacific. Generally, species had higher niche width and overlap in areas of high prey availability, and this was particularly evident for chum salmon. In addition to the large-scale trophic patterns, our data revealed novel fine-scale spatial patterns, including latitudinal, onshore-offshore, and cross-gyre gradients. Our results showed that pink tended to be more generalist consumers, and their diets may be a better reflection of overall prey presence and abundance in the environment. Conversely, chum and sockeye tended to be more specialist consumers, and their diets may provide a better reflection of interspecies dynamics or prey availability. This study provides a baseline for comparison with current and future changes in salmon marine ecology and North Pacific ecosystems. Finally, we identify two important data gaps that need addressing, that of improved taxonomic resolution diet data for Pacific salmon and focused research on sub-mesoscale oceanographic features that may play an important role in salmon health and productivity.

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