Environmental associations of sponges in the Spermonde Archipelago, Indonesia

2007 ◽  
Vol 87 (6) ◽  
pp. 1669-1676 ◽  
Author(s):  
Daniel F.R. Cleary ◽  
Nicole J. de Voogd
Keyword(s):  
Environmental Variables ◽  
Sediment Load ◽  
Community Similarity ◽  
Spatial Variables ◽  
South West ◽  
Spatial Turnover ◽  
Reef Environments ◽  
Environmental Component ◽  
Variation Explained ◽  
Spermonde Archipelago

Relatively little is known about spatial turnover of marine benthic taxa in the diverse reef environments of Indonesia and how this is structured by environmental conditions. In the present study the community similarity of sponges was related to environmental and spatial variables. In total, 150 sponge species (N=15,842) were sampled within the Spermonde Archipelago in the Makassar Strait, off south-west Sulawesi. Ordination revealed that sponges are primarily structured by a complex interaction between depth, exposure and on-to-offshore variation in environmental variables. Together, environmental and spatial variables explained 56.9% of the variation in similarity of which 10.9% was due to environmental variables alone, 2.6% due to spatial variables alone and 43.4% due to covariation of environmental and spatial variables. The large amount of variation explained by the spatially structured environmental component is due to a strong on-to-offshore gradient in a number of environmental variables including temperature, velocity, salinity and suspended sediment load. Ordination was also used to identify associations between species and environmental variables.

scholarly journals Using trait data improves correlation between environment and community data only if abundances are considered

2021 ◽  
Author(s):  
Attila Lengyel ◽  
Sándor Barabás ◽  
Boglárka Berki ◽  
Anikó Csecserits ◽  
Adrienn Gyalus ◽  
...  
Keyword(s):  
Explanatory Power ◽  
Seed Mass ◽  
Analysis Data ◽  
Variance Partitioning ◽  
Procrustes Analysis ◽  
Geographical Distance ◽  
Spatial Variables ◽  
Environmental Matching ◽  
Variation Explained ◽  
Analysis Models

AbstractA straightforward way to explore variation between communities is to calculate dissimilarity indices and relate them with environmental and spatial variables. Communities are most often represented by the (relative) abundances of taxa they comprise; however, more recently, the distribution of traits of organisms included in the communities has been shown more strongly related to ecosystem properties. In this study, we test whether taxon- or trait-based dissimilarity is correlated more tightly with environmental difference and geographical distance and how the abundance scale influences this correlation. Our study system is grassland vegetation in Hungary, where we sampled vegetation plots spanning a long productivity gradient from open dry grasslands to marshes in three sites. We considered three traits for vascular plants: canopy height, specific leaf area and seed mass. We obtained field estimates of normalized vegetation difference index (NDVI) as proxy of productivity (water availability) for each plot. We calculated between-community dissimilarities using a taxon-based and a trait-based index, using raw and square-root transformed abundances and presence/absence data. We fitted distance-based redundancy analysis models with NDVI difference and geographical distance on the dissimilarity matrices and evaluated them using variance partitioning. Then, using the pooled data, we calculated non-metric multidimensional scaling ordinations (NMDS) from all types of dissimilarity matrices and made pairwise comparisons using Procrustes analysis. Data analysis was done separately for the three sites.We found that taxonomical dissimilarity matches environmental and spatial variables better when presence/absence data is used instead of abundance. This pattern was mainly determined by the increasing variation explained by space at the presence/absence scale. In contrast to this trend, with trait-based dissimilarity, accounting for abundance increased explained variation significantly due to the higher explanatory power of NDVI. With abundance data, considering traits improved environmental matching to a great extent in comparison with taxonomical information. However, with presence/absence data, traits brought no advantage over taxon-based dissimilarity in any respect. Changing the abundance scale caused larger difference between ordinations in the case of trait-based dissimilarity than with taxonomical dissimilarity.We conclude that considering relevant traits improves environmental matching only if abundances are also accounted for.Supporting informationAdditional graphs supporting the results are presented as appendix.Open researchData used in this research are publicly available from Dryad ###link to be supplied upon acceptance###

Responses of plant functional types to environmental gradients in the south-west Ethiopian highlands

2011 ◽  
Vol 27 (03) ◽  
pp. 289-304 ◽  
Author(s):  
Desalegn Wana ◽  
Carl Beierkuhnlein
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Relative Abundance ◽  
Environmental Variables ◽  
Environmental Gradients ◽  
Plant Functional Types ◽  
The South ◽  
Ethiopian Highlands ◽  
South West ◽  
Functional Types

Abstract:Plant functional types across environmental gradients can be considered as a powerful proxy that reveals vegetation–environment relationships. The objectives of this study were to investigate the response in the relative abundance of plant functional types along altitudinal gradients and to examine the relationship of plant functional types to environmental variables. The study was conducted in the Gughe-Amaro Mountains, in the south-west Ethiopian highlands. We established 74 plots with an area of 400 m2(20 × 20 m) each along altitudinal ranges between 1000 and 3000 m asl. Data on site environmental conditions and on the abundance of plant functional types were analysed using the constrained linear ordination technique (RDA) in order to identify the relationships between plant functional types and environmental variables. Altitude, soil organic carbon, soil sand fraction and surface stone cover were significantly related to the relative abundance of plant functional types across the gradient. Tussocks and thorns/spines were abundant in lower altitudinal ranges in response to herbivory and drought while rhizomes and rosettes were abundant at higher altitudes in response to the cold. Generally our results show that topographic attributes (altitude and slope) as well as soil organic carbon play an important role in differentiating the relative abundance of plant functional types in the investigated gradient. Thus, considering specific plant functional types would provide a better understanding of the ecological patterns of vegetation and their response to environmental gradients in tropical regions of Africa prone to drought.

scholarly journals Factors that influence the beta-diversity of spider communities in northwestern Argentinean Grasslands

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1946 ◽  
Author(s):  
Sandra M. Rodriguez-Artigas ◽  
Rodrigo Ballester ◽  
Jose A. Corronca
Keyword(s):  
Beta Diversity ◽  
Environmental Variables ◽  
Regional Scale ◽  
Geographic Distance ◽  
Species Replacement ◽  
Community Similarity ◽  
Dispersal Capacity ◽  
Assembly Structure ◽  
Dispersion Capacity ◽  
Spider Communities

Beta-diversity, defined as spatial replacement in species composition, is crucial to the understanding of how local communities assemble. These changes can be driven by environmental or geographic factors (such as geographic distance), or a combination of the two. Spiders have been shown to be good indicators of environmental quality. Accordingly, spiders are used in this work as model taxa to establish whether there is a decrease in community similarity that corresponds to geographic distance in the grasslands of the Campos & Malezales ecoregion (Corrientes). Furthermore, the influence of climactic factors and local vegetation heterogeneity (environmental factors) on assemblage composition was evaluated. Finally, this study evaluated whether the differential dispersal capacity of spider families is a factor that influences their community structure at a regional scale. Spiders were collected with a G-Vac from vegetation in six grassland sites in the Campos & Malezales ecoregion that were separated by a minimum of 13 km. With this data, the impact of alpha-diversity and different environmental variables on the beta-diversity of spider communities was analysed. Likewise, the importance of species replacement and nesting on beta-diversity and their contribution to the regional diversity of spider families with different dispersion capacities was evaluated. The regional and site-specific inventories obtained were complete. The similarity between spider communities declined as the geographic distance between sites increased. Environmental variables also influenced community composition; stochastic events and abiotic forces were the principal intervening factors in assembly structure. The differential dispersal capacity of spider groups also influenced community structure at a regional scale. The regional beta-diversity, as well as species replacement, was greater in high and intermediate vagility spiders; while nesting was greater in spiders with low dispersion capacity. Geographic distance, among other factors (climate, and active and passive dispersion capacity), explains assembly structure and the decrease spider community similarity between geographically distant sites. Spiders with the highest dispersal capacity showed greater species replacement. This may be due to the discontinuity (both natural and anthropic) of the grasslands in this ecoregion, which limits the dispersal capacity of these spiders, and their close dependence on microhabitats. The dispersal capacity of the least vagile spiders is limited by geographic distance and biotic factors, such as competition, which could explain the nesting observed between their communities.

Abundance and genetic variation of the coral-killing cyanobacteriospongeTerpios hoshinotain the Spermonde Archipelago, SW Sulawesi, Indonesia

2015 ◽  
Vol 96 (2) ◽  
pp. 453-463 ◽  
Author(s):  
Esther van der Ent ◽  
Bert W. Hoeksema ◽  
Nicole J. de Voogd
Keyword(s):  
Genetic Variation ◽  
Community Structure ◽  
Benthic Community ◽  
Habitat Preferences ◽  
Benthic Community Structure ◽  
Spatial Variables ◽  
Terpios Hoshinota ◽  
The City ◽  
Spermonde Archipelago

The cyanobacteriospongeTerpios hoshinotais expanding its range across the Indo-Pacific. This species can have massive outbreaks on coral reefs, actively kill corals it overgrows and affect the entire benthic community. Although it has received much attention on the post-outbreak follow-up, little is known about its ecology, habitat preferences, and the possible environmental triggers that cause its outbreaks. We present a baseline study in the Spermonde Archipelago, Indonesia, whereT. hoshinotawas first observed in 2012. We surveyed 27 reefs and recorded patches between 14 and 217 cm2, at four reef sites (~15% cover). The sponge was found on both mid-shelf and outer shelf reefs but not close to the coast and the city of Makassar. Differences in benthic community structure, as well as spatial variables relating to the on-to-offshore gradient in the Spermonde archipelago, neither constrained nor promoted its expansion. Patches of the sponge were mostly overgrowing branching corals, belonging to Acroporidae species. Genetic variation withinT. hoshinotawas studied by sequencing partitions of the mitochondrial CO1 and nuclear ribosomal 28S gene. Two haplotypes were found within the Spermonde archipelago, which differed from the CO1 sequence in GenBank. The present study provides an indication of habitat preferences ofT. hoshinotain non-outbreak conditions, although it is still unclear which environmental conditions may lead to the onset of its outbreaks.

scholarly journals Evaluación del consumo de alcohol en adolescentes mexicanos: un enfoque desde la economía conductual

2021 ◽  
Vol 7 (1) ◽  
pp. 7-15
Author(s):  
Sarahí Alanís Navarro ◽  
Shoshana Berenzon Gorn ◽  
Francisco Lorenzo Juárez García
Keyword(s):  
High School Students ◽  
Alcohol Consumption ◽  
Regression Model ◽  
Environmental Variables ◽  
Multiple Linear Regression Model ◽  
Social Contexts ◽  
Preventive Interventions ◽  
School Students ◽  
Environmental Component ◽  
The Impact

Introduction: the impact of programs to prevent alcohol consumption in adolescents can be increased by incorporating an environmental component. This paper explores the usefulness of behavioral economics to analyze the preference for the substance as a function of environmental variables. Objective: to evaluate the level of alcohol consumption in a group of Mexican adolescents, as a function of sex, age, access to consumption and reinforcement derived from substance-free activities. Method: a total of 7,569 high school students participated: 51% were male and 49% female. A multiple linear regression model was used to evaluate how the selected variables are related to the level of alcohol consumption. Results: the regression model was adjusted (F = 202.423, p < 0.01) and explained 33.6% of the variance (R2 = 0.336). Gender (being male), age, and access to consumption in social contexts were positively associated with the level of alcohol consumption. Academic, prosocial and cultural activities were negatively related to alcohol consumption; while the use of electronic media, social, physical and recreational activities had a positive relationship. Discussion and conclusions: tit is necessary to reduce access to alcohol consumption, both commercially, and in social and family contexts. Preventive interventions should promote the involvement of adolescents in activities incompatible with consumption and incorporate a social component to increase their level of reinforcement.

Differences among regions in environmental predictors of primate community similarity affect conclusions about community assembly

2019 ◽  
Vol 35 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Lydia Beaudrot ◽  
Andrew J. Marshall
Keyword(s):  
Community Assembly ◽  
Environmental Variables ◽  
Geographic Distance ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Community Similarity ◽  
Primate Communities ◽  
Assembly Mechanism ◽  
Primate Community ◽  
Environmental Distance

AbstractUnderstanding why ecological communities contain the species they do is a long-standing question in ecology. Two common mechanisms that affect the species found within communities are dispersal limitation and environmental filtering. Correctly identifying the relative influences of these mechanisms has important consequences for our understanding of community assembly. Here variable selection was used to identify the environmental variables that best predict tropical forest primate community similarity in four biogeographic regions: the Neotropics, Afrotropics, Madagascar and the island of Borneo in South-East Asia. The environmental variables included net primary productivity and altitude, as well as multiple temperature, precipitation and topsoil variables. Using the best environmental variables in each region, Mantel and partial Mantel tests were used to reanalyse data from a previously published study. The proportion of variance explained increased for each region. Despite increases, much of the variation remained unexplained for all regions (R2: Africa = 0.45, South America = 0.16, Madagascar = 0.28, Borneo = 0.10), likely due to different evolutionary and biogeographic histories within each region. Nonetheless, substantial variation among regions in the environmental variables that best predicted primate community similarity were documented. For example, none of the 14 environmental variables was included for all four regions, yet each variable was included for at least one region. Contrary to prior results, environmental filtering was an important assembly mechanism for primate communities in tropical forests worldwide. Geographic distance more strongly predicted African and South American communities whereas environmental distance more strongly predicted Malagasy and Bornean communities. These results suggest that dispersal limitation structures primate communities more strongly than environmental filtering in Africa and in South America whereas environmental filtering structures primate communities more strongly than dispersal limitation in Madagascar and Borneo. For communities defined by genera, environmental distance more strongly predicted primate communities than geographic distance in all four regions, which suggests that environmental filtering is a more influential assembly mechanism at the genus level. Therefore, a more nuanced consideration of environmental variables affects conclusions about the influences of environmental filtering and dispersal limitation on primate community structure.

scholarly journals Diversity of palm communities at different spatial scales in a recently fragmented tropical landscape

2016 ◽  
Vol 182 (2) ◽  
pp. 451-464 ◽  
Author(s):  
Luke Browne ◽  
Jordan Karubian
Keyword(s):  
Species Richness ◽  
Environmental Variables ◽  
Forest Cover ◽  
Fragment Size ◽  
Spatial Scales ◽  
Landscape Fragmentation ◽  
Community Similarity ◽  
Biological Communities ◽  
Palm Species ◽  
Baseline Information

Abstract Habitat loss and landscape fragmentation are often associated with changes in biological communities at different spatial scales. Our goal in this study was to identify fragment characteristics and environmental variables linked to palm species richness, abundance and community similarity at local and landscape spatial scales and to contrast these patterns between adults and juveniles. We sampled palm communities in 22 fragments of Chocó rainforest in and around the Mache-Chindul Ecological Reserve in north-western Ecuador, where we recorded 9991 individuals of 23 palm species. At the landscape scale, fragment size and surrounding forest cover were not associated with species richness or abundance for either adults or juveniles. However, community similarity of juveniles was related to surrounding forest cover and the abundance of juveniles and adults increased with elevation. At the local scale, adults and juveniles differed in their relationships to environmental variables and distance to fragment edge: juveniles showed reduced species richness and different community composition near fragment edges compared with interior habitat, but adults did not. These results provide baseline information on palm communities in a poorly studied conservation hotspot and highlight the importance of considering multiple spatial scales and life stages in studies of habitat fragmentation.

Sign in / Sign up

Export Citation Format

Share Document