Diversity metrics of spider communities associated with an understorey plant in tropical rain forest fragments

AbstractHuman activities change the biodiversity of ecological communities in at least three dimensions: ecologically, taxonomically and functionally. Gathering information on these three dimensions allows the improvement of biodiversity assessments and the increased understanding of anthropogenic impact on natural communities. In this study, we analysed the spider community associated with the tropical plant Heliconia aurantiaca in two contrasting habitat types: continuous forest and forest fragments in south-eastern Mexico. We examined the foliage, stems and bracts of H. aurantiaca individuals in both habitats. We categorized each spider species according to its behavioural and functional traits. We analysed ecological diversity using Hill numbers, taxonomic distinctness and functional diversity using the FRic index. Overall, we collected a total of 110 spiders, of which 44 individuals from 29 species were found in continuous forests, with 66 individuals from 36 species in forest fragments. We found greater ecological diversity in continuous forest than in fragments. In contrast, we found lower functional diversity in continuous forest than in fragments. Taxonomic diversity showed no significant difference between habitats. Forest fragmentation affected the biodiversity of spiders by disrupting species composition and function, which may lead to other ecological changes such as predator–prey interactions and other aspects of ecosystem functioning.

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Seasonal Analysis of Taxonomic and Functional Diversity of Poneromorph Ant Assemblages in the Amazon Forest

Sociobiology ◽

10.13102/sociobiology.v63i3.1053 ◽

2016 ◽

Vol 63 (3) ◽

pp. 941 ◽

Cited By ~ 1

Author(s):

Luana Priscila de Carvalho Pereira ◽

Fábio Souto Almeida ◽

André Barbosa Vargas ◽

Marcel Santos de Araújo ◽

Antônio José Mayhé-Nunes ◽

...

Keyword(s):

Functional Groups ◽

Functional Diversity ◽

Taxonomic Diversity ◽

Native Forest ◽

Amazon Forest ◽

Functional Richness ◽

Significant Difference ◽

Seasonal Analysis ◽

Ant Diversity ◽

Dry And Rainy Seasons

The present study aimed at assessing the effects of climate seasonality on poneromorph ants in the Brazilian Amazon, by studying variations in composition, richness, and taxonomic and functional diversity. The study was carried out in the Tapirapé-Aquiri National Forest, southeastern Pará State. We collected poneromorph ants in three areas of native forest with pitfall traps and sardine baits on the ground and vegetation, in two dry and rainy seasons. We collected 46 species of poneromorph ants, which belong to two subfamilies and eleven genera. The species composition, richness and taxonomic diversity did not vary significantly between seasons. There was no significant difference in the frequency of species of functional groups between dry and rainy seasons. There was no significant difference in the average richness and average diversity of functional groups between the dry and rainy seasons. In our study we found no seasonal differences in composition, taxonomic and functional richness and diversity of poneromorph ants in the Amazon, which is useful for future studies that aim at using those ants as bioindicators. In addition, the identification of the species made in the present study has special relevance as it contributes to advance the knowledge of poneromorph ant diversity in the Amazon.

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The cryptic impacts of invasion: Functional homogenization of tropical ant communities by invasive fire ants

10.1101/611749 ◽

2019 ◽

Author(s):

Mark K. L. Wong ◽

Benoit Guénard ◽

Owen T. Lewis

Keyword(s):

Functional Diversity ◽

Taxonomic Diversity ◽

Individual Species ◽

Ecological Communities ◽

Ant Communities ◽

Invasive Insects ◽

Tropical Grasslands ◽

Functional Richness ◽

Functional Identities ◽

Functional Homogenization

AbstractInvasive insects represent major threats to ecosystems worldwide. Yet their effects on the functional dimension of biodiversity, measured as the diversity and distribution of traits, are overlooked. Such measures often determine the resilience of ecological communities and the ecosystem processes they modulate. The fire ant Solenopsis invicta is a highly problematic invasive species occurring on five continents. Its impacts on the taxonomic diversity of native ant communities have been studied but its impacts on their functional diversity are unknown. Comparing invaded and uninvaded plots in tropical grasslands of Hong Kong, we investigated how the presence of S. invicta affects the diversity and distribution of ant species and traits within and across communities, the functional identities of communities, and functionally unique species. We calculated the functional diversity of individual species, including the trait variation from intraspecific polymorphisms, and scaled up these values to calculate functional diversity at the community level. Invasion had only limited effects on species richness and functional richness, which were 13% and 8.5% lower in invaded communities respectively. In contrast, invasion had pronounced effects on taxonomic and functional composition due to turnover in species and trait values. Furthermore, invaded communities were functionally more homogeneous, displaying 23% less turnover and 56% more redundancy than uninvaded communities, as well as greater clustering and lower divergence in trait values. Invaded communities had fewer functionally-unique individuals and were characterized by ant species with narrower heads and bodies and shorter mandibles. Our results suggest that studies based only on taxonomic measures of diversity or indices describing trait variety risk underestimating the full ramifications of invasions. Investigating the diversity and distributions of traits at species, community and landscape levels can reveal the cryptic impacts of alien species which, despite causing little taxonomic change, may substantially modify the structure and functioning of ecological communities.

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Traits matter: When rarity means more than abundance to functional diversity

10.7287/peerj.preprints.26840 ◽

2018 ◽

Author(s):

Thomas J. Trott

Keyword(s):

Functional Diversity ◽

Rare Species ◽

Gulf Of Maine ◽

Taxonomic Diversity ◽

Abundant Species ◽

Rocky Intertidal ◽

Taxonomic Distinctness ◽

Ecological Traits ◽

Mere Presence ◽

Species Removal

Rare species can significantly contribute to ecosystem stability and resiliency. Furthermore, wider taxonomic trees can support a wider range of functional diversity. These ideas with the notion that functional diversity leads to ecosystem resiliency suggest rare species can disproportionately increase taxonomic and functional diversity. To test this hypothesis, functional distinctness was used to estimate functional diversity, and average taxonomic distinctness to evaluate taxonomic diversity for rocky intertidal species assemblages sampled by three surveys separated by years examining a total 41 locations spanning the Gulf of Maine. Fifteen life-history and ecological traits were assigned to the 95 species observed using a total of 90 options. Species were ranked either rare or abundant using incidence. Influence of rarity on functional and taxonomic distinctness was appraised by comparing intact assemblages to ones where rare species (observed once per location) were removed to imitate rare species loss. For intact assemblages, functional and taxonomic distinctness correlated. However, rare species removal significantly decreased functional diversity for some assemblages while taxonomic diversity was less affected. Removal of abundant species produced no significant effects. Results demonstrate rare species can increase functional diversity without necessarily being rare taxonomically. Abundant species exert their effects through their numbers; mere presence makes no difference.

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Conventional and genetic measures of seed dispersal for Dipteryx panamensis (Fabaceae) in continuous and fragmented Costa Rican rain forest

Journal of Tropical Ecology ◽

10.1017/s0266467407004488 ◽

2007 ◽

Vol 23 (6) ◽

pp. 635-642 ◽

Cited By ~ 14

Author(s):

Thor Hanson ◽

Steven Brunsfeld ◽

Bryan Finegan ◽

Lisette Waits

Keyword(s):

Seed Dispersal ◽

Costa Rican ◽

Forest Fragments ◽

Molecular Tools ◽

Evolutionary Potential ◽

Dipteryx Panamensis ◽

Continuous Forest ◽

Adult Trees ◽

Significant Difference ◽

Dispersal Distances

The effects of habitat fragmentation on seed dispersal can strongly influence the evolutionary potential of tropical forest plant communities. Few studies have combined traditional methods and molecular tools for the analysis of dispersal in fragmented landscapes. Here seed dispersal distances were documented for the tree Dipteryx panamensis in continuous forest and two forest fragments in Costa Rica, Central America. Distance matrices were calculated between adult trees (n = 283) and the locations of seeds (n = 3016) encountered along 100 × 4-m transects (n = 77). There was no significant difference in the density of seeds dispersed > 25 m from the nearest adult (n = 253) among sites. There was a strong correlation between the locations of dispersed seeds and the locations of overstorey palms favoured as bat feeding roosts in continuous forest and both fragments. Exact dispersal distances were determined for a subset of seeds (n = 14) from which maternal endocarp DNA could be extracted and matched to maternal trees using microsatellite analysis. Dispersal within fragments and from pasture trees into adjacent fragments was documented, at a maximum distance of 853 m. Results show no evidence of a fragmentation effect on D. panamensis seed dispersal in this landscape and strongly suggest bat-mediated dispersal at all sites.

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Continuous forest has greater taxonomic, functional and phylogenetic plant diversity than an adjacent naturally fragmented forest

Journal of Tropical Ecology ◽

10.1017/s0266467414000194 ◽

2014 ◽

Vol 30 (4) ◽

pp. 323-333 ◽

Cited By ~ 18

Author(s):

Miguel A. Munguía-Rosas ◽

Selmy G. Jurado-Dzib ◽

Candy R. Mezeta-Cob ◽

Salvador Montiel ◽

Armando Rojas ◽

...

Keyword(s):

Tropical Forest ◽

Forest Fragmentation ◽

Plant Diversity ◽

Phylogenetic Diversity ◽

Taxonomic Diversity ◽

Evergreen Forest ◽

Forest Fragments ◽

Fragmented Forest ◽

Continuous Forest ◽

Functional And Phylogenetic Diversity

Abstract:Several studies have evaluated the short-term effects of tropical forest fragmentation on plant taxonomic diversity, while only a few have evaluated its effects on functional or phylogenetic diversity. To our knowledge no study has looked at the long-term consequences of tropical forest fragmentation on the three main components of plant diversity simultaneously: taxonomic, functional and phylogenetic diversity. We sampled the vascular flora using belt transects (50 × 4 m) in a continuous tropical semi-evergreen forest (16 transects) and in an adjacent naturally fragmented forest (fragments of 1.7-My-old semi-evergreen forest immersed in a mangrove/sedge matrix) (18 transects), and compared their taxonomic, functional and phylogenetic plant diversity. There were 36 species in the continuous forest and 28 in the fragmented forest. Continuous forest was taxonomically more diverse (25%) than the fragmented forest. All functional diversity metrics were greater (6–33%) in the continuous than in the fragmented forest. Phylogenetic diversity was 19% greater and phylogenetically more overdispersed in the continuous forest than in the fragmented forest. The results suggest that in the fragmented forest not only is taxonomic plant diversity lower, but functional and phylogenetic diversity are as well. The negative effects of forest fragmentation on plant diversity seem to be chronic.

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Traits matter: When rarity means more than abundance to functional diversity

10.7287/peerj.preprints.26840v1 ◽

2018 ◽

Author(s):

Thomas J. Trott

Keyword(s):

Functional Diversity ◽

Rare Species ◽

Gulf Of Maine ◽

Taxonomic Diversity ◽

Abundant Species ◽

Rocky Intertidal ◽

Taxonomic Distinctness ◽

Ecological Traits ◽

Mere Presence ◽

Species Removal

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Bird species that occupy river edge in continuous forest tend to be less sensitive to forest fragmentation

Revista Brasileira de Ornitologia ◽

10.1007/bf03544468 ◽

2019 ◽

Vol 27 (3) ◽

pp. 172-186

Author(s):

Barbara Rocha Arakaki Lindsey ◽

Gabriela Menezes Bochio ◽

Luiz dos Anjos

Keyword(s):

Forest Fragmentation ◽

Bird Species ◽

Forest Edge ◽

Bird Communities ◽

Forest Fragments ◽

Small Stream ◽

Edge Habitat ◽

Forest Interior ◽

Continuous Forest ◽

Significant Difference

AbstractAlong a distance gradient from a given river, two types of habitat can be recognized: natural river edge and forest interior, each one with its own vegetation characteristics and dynamics. In a continuous area of the Brazilian Atlantic Forest, we investigated (1) if bird communities are different between a riverbank of a small stream and an inland forest habitat; (2) if the species of the river edge habitat are the ones that persist in the most in forest fragments after deforestation of a continuous forest; (3) if the river edge habitat species are those that are less sensitive to forest fragmentation. It is expected that there are differences in the bird communities and the occupancy of some species between the two habitats. We allocated 16 sampling points in each of the habitats and sampled the birds by point counts with a short radius of 30 m. Results suggest that there is a significant difference between the composition of the bird communities of the river edge and forest interior habitats, although the species richness is similar. Six species were more likely to occupy the river edge and 14 species had a greater probability of occupancy in the forest interior. Species associated with the river edge habitat (15 species) tend not to be sensitive to forest fragmentation (12 species). In this study, we demonstrated that river-border species of continuous forest areas form a significant part of the bird communities that persist in small forest fragments, with intense edge effect. This shows that not all forest edge species are the result of the colonization from open areas. Congruently, species that occupy the most distant areas from the river vegetation in a continuous forest are those more sensitive to forest fragmentation.

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Governance Disclosure on the Internet by Leading Indian Public Sector Companies

Think India ◽

10.26643/think-india.v22i2.8716 ◽

2019 ◽

Vol 22 (2) ◽

pp. 174-187

Author(s):

Harmandeep Singh ◽

Arwinder Singh

Keyword(s):

Public Sector ◽

Financial Information ◽

Three Dimensions ◽

The Internet ◽

Web Pages ◽

Non Profit ◽

Index Approach ◽

Significant Difference ◽

Governance Disclosure ◽

The Web

Nowadays, internet satisfying people with different services related to different fields. The profit, as well as non-profit organization, uses the internet for various business purposes. One of the major is communicated various financial as well as non-financial information on their respective websites. This study is conducted on the top 30 BSE listed public sector companies, to measure the extent of governance disclosure (non-financial information) on their web pages. The disclosure index approach to examine the extent of governance disclosure on the internet was used. The governance index was constructed and broadly categorized into three dimensions, i.e., organization and structure, strategy & Planning and accountability, compliance, philosophy & risk management. The empirical evidence of the study reveals that all the Indian public sector companies have a website, and on average, 67% of companies disclosed some kind of governance information directly on their websites. Further, we found extreme variations in the web disclosure between the three categories, i.e., The Maharatans, The Navratans, and Miniratans. However, the result of Kruskal-Wallis indicates that there is no such significant difference between the three categories. The study provides valuable insights into the Indian economy. It explored that Indian public sector companies use the internet for governance disclosure to some extent, but lacks symmetry in the disclosure. It is because there is no such regulation for web disclosure. Thus, the recommendation of the study highlighted that there must be such a regulated framework for the web disclosure so that stakeholders ensure the transparency and reliability of the information.

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LARGE QUANTUM GRAVITY EFFECTS: CYLINDRICAL WAVES IN FOUR DIMENSIONS

International Journal of Modern Physics D ◽

10.1142/s0218271800000633 ◽

2000 ◽

Vol 09 (06) ◽

pp. 669-686 ◽

Cited By ~ 17

Author(s):

MARÍA E. ANGULO ◽

GUILLERMO A. MENA MARUGÁN

Keyword(s):

Quantum Gravity ◽

Symmetry Axis ◽

Point Of View ◽

Three Dimensions ◽

Asymptotic Region ◽

Four Dimensions ◽

Cylindrical Waves ◽

Significant Difference ◽

Gravity Effects ◽

Linearly Polarized

Linearly polarized cylindrical waves in four-dimensional vacuum gravity are mathematically equivalent to rotationally symmetric gravity coupled to a Maxwell (or Klein–Gordon) field in three dimensions. The quantization of this latter system was performed by Ashtekar and Pierri in a recent work. Employing that quantization, we obtain here a complete quantum theory which describes the four-dimensional geometry of the Einstein–Rosen waves. In particular, we construct regularized operators to represent the metric. It is shown that the results achieved by Ashtekar about the existence of important quantum gravity effects in the Einstein–Maxwell system at large distances from the symmetry axis continue to be valid from a four-dimensional point of view. The only significant difference is that, in order to admit an approximate classical description in the asymptotic region, states that are coherent in the Maxwell field need not contain a large number of photons anymore. We also analyze the metric fluctuations on the symmetry axis and argue that they are generally relevant for all of the coherent states.

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