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Beachcomber Biology: The Shannon-Weiner Species Diversity Index
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... The Shannon-Weiner index (H′) is a commonly used metric in ecology that quantifies the complexity of an ecosystem or community by taking into account both the number of species available and their relative abundance (Nolan and Callahan 2006;Omayio and Mzungu 2019). The approach employed to evaluate the abundance of trees, shrubs, and herbs was total enumeration. ...
... In the context of agroforestry, the SWI (Eq. 1) can be used to measure the diversity of tree species and crops grown in a particular agroforestry system (Nolan and Callahan 2006;Omayio and Mzungu 2019). A high value of the index indicates a more diverse system, while a low value indicates less diversity of species (Nolan and Callahan 2006). ...
... In the context of agroforestry, the SWI (Eq. 1) can be used to measure the diversity of tree species and crops grown in a particular agroforestry system (Nolan and Callahan 2006;Omayio and Mzungu 2019). A high value of the index indicates a more diverse system, while a low value indicates less diversity of species (Nolan and Callahan 2006). The following equation is used to calculate this index. ...
This study examines the intricate interplay between species diversity and socio-cultural importance (SCI) in the homestead agroforestry (HAF) systems of Sivasagar, a floodplain district nestled in the upper Brahmaputra Valley Agro-climatic region of Assam, India. Over the past decade, the district has witnessed notable ecological, cultural, and economic shifts propelled by modern agricultural practices, market-driven economies, recurrent floods, and industrial and infrastructural activities. Thus, the study endeavors to unravel the main drivers of these changes and their impacts on species diversity and socio-cultural values of the homestead agroforestry, offering insights into the implications for the region's rural ecology and culture. To achieve its aims, the research employs a range of methodologies, including in-depth field observations, household surveys, oral interviews, participatory rural appraisal, rapid rural appraisal, and focus group discussions to evaluate plant species diversity and their Socio-Cultural Importance (SCI) within HAF systems. The findings indicate a decline in indigenous plant species due to the transition from traditional to market-oriented agriculture, significantly affecting the socio-cultural fabric of the communities. This includes the displacement of traditional practices with market-based alternatives, erosion of traditional knowledge, and a threat to the region's ecological and cultural integrity. These findings underscore the need for a balanced approach that honors traditions and ecological heritage while addressing challenges arising from modernization and external influences. Thus, this research serves as a crucial foundation for informed decision-making, providing insights to safeguard the unique ecology and culture of rural areas in the Brahmaputra Valley, with a specific focus on the Sivasagar district in Assam, India. It also directs efforts towards forging sustainable solutions to ensure the future well-being of these rural communities, offering valuable lessons for similar regions grappling with ecological and cultural transformations.
... Shannon's diversity index is used for the overall assessment of richness and complexity. Its values increase both with an increase in the number of alleles and with an increase in the equality of frequencies between them (Nolan and Callahan, 2006). ...
... Model fit was attained using a Poisson distribution for species richness. Unlike species richness, a linear mixed model (LMM) was chosen for the analysis of Shannon diversity (Nolan and Callahan 2006;Ramezani 2012) using the "lme4" package (Bates et al. 2014). Shannon diversity was square route transformed to improve model fit. ...
Context
Increased cocoa cultivation (Theobroma cacao) has led to the conversion of over 6 million hectares of rainforest to cocoa farmlands in West Africa. Globally, pollinator decline has been driven by land use changes. Though land use change through cocoa expansion may affect insect pollinators and, by extension, pollination services, this has rarely been assessed.
Objectives
Our study examined the relationships between the proportion of natural forest in the landscape (reduced primarily due to cocoa expansion) and flower-visiting insect abundance, and bee abundance, richness, diversity and community composition. The effect of pan trap type (aerial or ground) was also tested.
Methods
Eighteen sites were selected along a gradient of an increasing proportion of natural forests in the surrounding landscape (from 9 to 100%). Ground and aerial pan traps were deployed in each site to sample flower-visiting insects. Two sampling sessions were conducted; during the rainy season in 2021 and during the dry season in 2022.
Results
The abundances of Coleoptera, Hymenoptera and Hemiptera increased with increasing proportion of natural forests in the landscape, while Diptera decreased. Natural forest and trap type did not significantly influence bee abundance, species richness, and Shannon diversity. However, bee community composition differed along the forest gradient, indicating that forests and cocoa farms harbour different bee communities. Ground pan traps captured more insects (61% of 19,927 flower-visiting insects) than aerial pan traps, which was driven by the Diptera as the abundances of the other orders were not significantly related to trap type.
Conclusions
Preserving natural forest in cocoa-growing landscapes is important to sustain the coexistence of diverse flower-visiting insect communities owing to their differential responses to the proportions of natural forests.
... Individuals were classified as either adult or juvenile following size-at-age data when available (COSEWIC, 2003), otherwise 25.0 mm was used to designate the size limit of juvenile unionids (Haag and Warren, 2007;Maclennan-Nobrega et al., 2024). Abundance data were used to calculate the Shannon-Weiner diversity (H) index (Nolan and Callahan, 2006): ...
... To further quantify and hence differentiate between Norse and Inuit play object use, we used the so-called Shannon Diversity Index and its associated values of evenness and richness to describe basic dimensions of our corpus of objects ( Table 2). The index, which is just one way to describe diversity in archaeology (see Dunnell, 1989) and a range of other disciplines, estimates diversity, here the number of object classes within the categories of play objects relative to the overall number of objects (Nolan & Callahan, 2006). Diversity is directly connected to innovation (Kuhn, 2020) and environmental risk (Fitzhugh, 2001): without diversity, there is no cultural evolution and hence no adaptation (cf. ...
Greenland is the world's largest island, but only a narrow strip of land between the Inland Ice and the sea is inhabitable. Yet, the Norse chose to settle here around ad 986. During the eleventh century ad , precontact Inuit people moved into Greenland from northern Alaska via Canada. Although the two cultures faced the same climatic changes during the Little Ice Age, the Inuit thrived, while the Norse did not, for multiple causes. The authors focus on one of these causes, the hitherto overlooked contribution of young children's learning strategies to societal adaptation. The detailed analysis of a large corpus of play objects reveals striking differences between the children's material culture in the two cultures: rich and diverse in the precontact Inuit material and more limited and normative in the Norse. Drawing on insights from developmental psychology, the authors discuss possible effects of play objects on children's future adaptability in variable climatic conditions.
... Significance was accepted at p < 0.05, for twotailed testing. For the gut microbiota, alpha diversity was measured by calculating the Shannon, Simpson, and Observed species indices57 . Pairwise statistical analyses regarding time, diet, and sex were performed. ...
Oligofructose prebiotic fiber supplementation has been reported to mitigate the effects of a high fat/high sucrose diet and reduce knee joint degeneration in male rats. However, few studies investigated the development of osteoarthritis and bone lesions as a function of sex and in joints other than the knee. This study was aimed at to quantifying the effect of a HFS diet and prebiotic fiber supplementation on shoulder joint health in male and female Sprague-Dawley rats. Rats were randomized into 6 groups: 2 groups fed a chow diet: Chow-Male n = 11, Chow-female n = 12; 2 groups fed a HFS diet: HFS-Male n = 11, HFS-Female n = 12; and 2 groups fed a prebiotic fiber supplement in addition to the HFS diet: Fiber-Male n = 6, Fiber- Female n = 12. After 12 weeks, shoulder joints were histologically assessed for OA. Body composition, serum lipid profile, insulin resistance and fecal microbiota were also assessed. Shoulders in male and female rats appear to be protected against degeneration when exposed to a HFS diet. Male rats developed bone lesions while females did not. Fiber supplementation was more effective in males than in females suggesting that fiber supplementation may have sex-specific effects on the gut microbiota.
... Th e formula is H′ = ∑ (Pi ln Pi), where Pi = proportion of the i th species and In = natural logarithm. Shannon-Wiener evenness index (E) (E = H′ /H max , where H′ = Shannon-Wiener diversity index; and H max = lnS = natural logarithm of the total number of species (S) (Kathleen et al., 2005;Sohil & Sharma, 2020) was used to calculate the species evenness of birds. In addition, Simpson's similarity index (SI) (SI = 2 C/A + B, where A = number of species that found in site A, B = number of species found in site B, and C = number of common species that found in site A and B) was used to evaluate the similarity between habitats with reference to species composition. ...
Avian diversity is among the key components of the earth’s biodiversity that serve as unique barometers for environmental change. Bird diversity in unprotected habitats such as reservoirs in the Tigray region is less known. A study was conducted to assess the avian diversity in highland reservoirs of the Tigray region, particularly at Maygundi and Maysye reservoirs and their adjoining habitats from August 2022 to March 2023, covering both wet and dry seasons. A line transect and point count methods aided by binoculars were used to estimate avian species diversity and distribution. Biodiversity indices and Two-way ANOVA were used to analyze the data. A total of 1,813 individual birds belonging to 151 species, 17 orders and 51 families were recorded during the study period. Egyptian goose was the most abundant species (19.58 %), followed by Little Grebe (10. 86 %), Eurasian Coot (7.00 %), Ruff and Yellow Mantle Widowbird (3.31 % for each). A significant variation in the number of bird species between wet and dry seasons (F = 1225, df = 1, P = 0.02) and between reservoirs (F = 484, df = 1, P = 0.03) was observed. However, there was no significant difference in abundance of birds between wet and dry seasons in both reservoirs (P > 0.05). Maysye reservoir had high bird species diversity (H′ = 3.66), while Maygundi reservoir had the lowest (H′ = 3.24). The study shows that sedimentation and habitat destruction due to anthropogenic activities, including the expansion of settlements; agriculture and livestock grazing were the main threats to bird diversity. The highland reservoirs and their adjoining habitats support high avian species diversity including endemic and endangered species revealing the importance of the sites for bird conservation. Therefore, urgent conservation measures are recommended for long-term bird conservation.
... The difference in species richness between pairs of zones ℎ = | − | + + Here; a: the number of species common to both regions, b: the number of species specific to the first region, c: the number of species specific to the second region. (Nolan and Callahan, 2006). One-way analysis of variance (ANOVA) was used to analyze the changes in total frequency and cover values in the Johnsson zones. ...
In this study, the vertical change of epiphytic lichen species on Quercus robur was examined in Johansson zones based on frequency and cover values. A total of 20 epiphytic lichen species were determined. Total frequency and cover values of epiphytic lichen species show significant changes in Johansson regions. Beta diversity and Shannon diversity index values shows significant change with Johansson zone pairs. There is a significant difference in epiphytic lichen diversity between the Z1Z2 zone pair corresponding to the base and middle part of trunk on trees, and the Z4Z5 zone pair corresponding to the branches. Athallia pyracea, Catillaria nigroclavata, Physcia adscendens and Rinodina pyrina were positively correlated with Johansson zones, while Phaeophyscia orbicularis was negatively correlated with Johansson zones. A. pyracea is an indicator species especially for thin branches (Z5). P. adscendens is an indicator for Z4 and Ph. orbicularis is for the trunk part of the tree (Z1, Z2 and Z3).
The glass eel fishing by-catch in the Minho River was evaluated by assessing its composition during the 2021–2022 fishing season and comparing results with the first data collected during the 1981-1982 season. Results showed that by-catch composition was mainly dominated by fish and crustaceans. Large reductions in glass eel and by-catch yields were observed, with decreases in both fish and invertebrate yields. The largest reductions were recorded for Anguilla anguilla (yellow eel), Atherina boyeri, Saduriella losadai and Palaemon longirostris. On the other hand, a few species showed an increase in both number of catches and yield, such as Crangon crangon and Gammarus spp. Decreases in glass eel and by-catch yields were less pronounced upstream. By-catch is mainly composed of estuarine species, with higher catches of marine species downstream. Most of the marine invertebrate species caught were correlated with the presence of marine red, green and brown algae. Small fish and juveniles of larger species were most commonly caught, with the most common species being Atherina boyeri, Pomatoschistus microps, Syngnathus abaster and Ammodytes tobianus. Similarly, invertebrate species such as Crangon crangon, Eurydice pulchra, Lekanesphaera rugicauda and Gastrosaccus spinifer were also important in the composition of the by-catch. High levels of marine fish stragglers and marine invertebrates associated with marine algae were also observed, in contrast to data collected in the 1980s, suggesting a possible shift in the composition of the lower estuarine fauna over the past 40 years.
Interactions between key landscape features in desert ecosystems such as shrubs and other foundation plants can influence avian community assembly. Bird species often use resources and microhabitats provided by these shrubs for food, perching sites, and as thermal refuges. Citizen science data, such as eBird, are broadly accessible and can be used to examine fine-scale avian distribution. Coupling this accessible data with key factors, such as native shrubs, can be used for conservation practices. eBird data offers the opportunity to examine avian communities across regional ecological gradients. Using eBird, we tested the hypothesis that shrub density and relative differences in aridity among sites within this region shape the structure of bird communities throughout Central California drylands. Shrub density positively influenced the observation rates of avian communities sampled. Decreasing aridity increased the positive associations of birds with shrubs. Citizen science data such as eBird offers promise for testing predictions at fine spatial scales, and further research can explore availability and reporting of data for other regions - particularly in drylands subject to substantial pressures from climate change globally. Simple landscape features in drylands, such as native shrub density and cover, offer a viable path forward for avian community conservation and potential habitat restoration in drylands in the face of a changing climate and increasing desertification.
National Audubon Society Field Guide to North American Seashells
- H Rehder
Rehder, H. 1981. National Audubon Society Field Guide to North American Seashells. Alfred A.
Knopf Pub.