scholarly journals Changing foodwebs of Indian aquatic ecosystems under the threats of invasive species: An overview

2021 ◽  
Vol 24 (2) ◽  
pp. 24-32
Author(s):  
Preetha Panikkar ◽  
M. Feroz Khan ◽  
U.K. Sarkar ◽  
B.K. Das
Keyword(s):  
Aquatic Ecosystems ◽  
Species Abundance ◽  
Open Water ◽  
Future Research ◽  
Exotic Fish ◽  
Management Actions ◽  
Invasive Fishes ◽  
Species Invasions ◽  
Species Abundance Distributions ◽  
Invasion Impacts

Abstract Biological invasions are a worldwide threat to the aquatic systems and have the potential to homogenize entire foodwebs and shift species abundance distributions to more skewed ones. Invasion impacts include effects on the foodweb structure and ecosystem functioning leading to a loss in native fish biodiversity and commercially important fisheries in many open water systems. The impacts of invasives are generally devastating as they spread in the foodweb with each species potentially interacting with multiple species. The foodweb modeling studies conducted in different inland aquatic ecosystems show that not all exotics cause a detrimental effect on the resilience of an ecosystem. Information on the foodweb structure and ecosystem properties is a prerequisite for formulating management protocols for conserving biodiversity, enhancement programmes and sustaining fisheries. The present paper reviews the impacts of invasive fishes in Indian aquatic ecosystems in the context of a changing foodweb scenario due to exotic fish species invasions. The information generated here could be applied for future research on similar ecosystems for deducing management actions.

scholarly journals Phylogenetic scale in ecology and evolution

2016 ◽  
Author(s):  
Catherine H. Graham ◽  
David Storch ◽  
Antonin Machac
Keyword(s):  
Community Ecology ◽  
Species Abundance ◽  
Future Research ◽  
Diversification Rates ◽  
Species Abundance Distributions ◽  
Practical Guidelines ◽  
Explicit Consideration ◽  
Patterns And Processes ◽  
Diversity Of Life ◽  
Insight Into

AbstractAimMany important patterns and processes vary across the phylogeny and depend on phylogenetic scale. Yet, phylogenetic scale has never been formally conceptualized and its potential remains largely unexplored. Here, we formalize the concept of phylogenetic scale, review how phylogenetic scale has been considered across multiple fields, and provide practical guidelines for the use of phylogenetic scale to address a range of biological questions.MethodsWe summarize how phylogenetic scale has been treated in macroevolution, community ecology, biogeography, and macroecology, illustrating how it can inform, and possibly resolve, some of the longstanding controversies in these fields. To promote the concept empirically, we define phylogenetic grain and extent, scale-dependence, scaling, and the domains of phylogenetic scale. We illustrate how existing phylogenetic data and statistical tools can be employed to investigate the effects of scale on a variety of well-known patterns and processes, including diversification rates, community structure, niche conservatism, or species-abundance distributions.Main conclusionsExplicit consideration of phylogenetic scale can provide new and more complete insight into many longstanding questions across multiple fields (macroevolution, community ecology, biogeography, macroevolution). Building on the existing resources and isolated efforts across fields, future research centered on phylogenetic scale might enrich our understanding of the processes that together, but over different scales, shape the diversity of life.

scholarly journals A biogeographical perspective on species abundance distributions: recent advances and opportunities for future research

2017 ◽  
Vol 44 (8) ◽  
pp. 1705-1710 ◽  
Author(s):  
Thomas J. Matthews ◽  
Paulo A.V. Borges ◽  
Eduardo Brito de Azevedo ◽  
Robert J. Whittaker
Keyword(s):  
Species Abundance ◽  
Future Research ◽  
Recent Advances ◽  
Species Abundance Distributions

scholarly journals An Overview of Ecosystem Service Studies in a Tropical Biodiversity Hotspot, Sri Lanka: Key Perspectives for Future Research

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 540
Author(s):  
Chaya Sarathchandra ◽  
Yirga Alemu Abebe ◽  
Iresha Lakmali Wijerathne ◽  
Sasith Tharanga Aluthwattha ◽  
Sriyani Wickramasinghe ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Sri Lanka ◽  
Ecosystem Service ◽  
Future Research ◽  
Species Introduction ◽  
Related Research ◽  
Management Actions ◽  
Service Category ◽  
Tropical Biodiversity ◽  
Published Evidence

Tropical island countries are often highly populated and deliver immense ecosystem service benefits. As human wellbeing depends on these ecosystems, proper management is crucial in the resource-rich tropical lands where there is less related research. Though ecosystem service and biodiversity studies are a promising path to inform the ecosystem management for these mostly developing countries, published evidence of using ecosystem service studies in decision making is lacking. The purpose of this study is to provide an overview of ecosystem services and related research in Sri Lanka, examining trends and gaps in how these studies are conceptualized. Out of the considered 220 peer-reviewed articles, the majority of articles (48.2%) were terrestrial and forest related while coastal ecosystems were considered in 33.2% of studies. In most studies, the ecosystem service category studied was provisioning (31.5%) followed by regulatory service (28.7%). Studies investigating and quantifying ecosystem services, pressures on ecosystems, and their management were fewer compared to studies related to biodiversity or species introduction. Moreover, studies investigating the value of ecosystem services and biodiversity to the communities or involvement of stakeholders in the development of management actions regarding the ecosystem services were rare in Sri Lanka, and an intense focus from future studies in these aspects is timely and necessary.

scholarly journals The use of nocturnal flights for barrier crossing in a diurnally migrating songbird

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Christie D. Lavallée ◽  
Saeedeh Bani Assadi ◽  
Alicia M. Korpach ◽  
James D. Ray ◽  
Jason D. Fischer ◽  
...  
Keyword(s):  
Energy Savings ◽  
Open Water ◽  
Gps Tracking ◽  
Future Research ◽  
Barrier Crossing ◽  
Migration Patterns ◽  
Migration Strategies ◽  
Diurnal Migrant ◽  
Time And Energy ◽  
High Degree

Abstract Background The migration patterns of land birds can generally be divided into those species that migrate principally during the day and those that migrate during the night. Some species may show individual plasticity in the use of day or night flight, particularly when crossing large, open-water or desert barriers. However, individual plasticity in circadian patterns of migratory flights in diurnally migrating songbirds has never been investigated. Methods We used high precision GPS tracking of a diurnal, migratory swallow, the purple martin (Progne subis), to determine whether individuals were flexible in their spring migration strategies to include some night flight, particularly at barrier crossing. Results Most (91%) of individuals made large (sometimes > 1000 km), open-water crossings of the Caribbean Sea and the Gulf of Mexico that included the use of night flight. 32% of all water crossings were initiated at night, demonstrating that night flight is not only used to complete large crossings but may confer other advantages for diurnal birds. Birds were not more likely to initiate crossings with supportive winds, however crossings were more likely when they reduced travel distances. Our results are consistent with diurnal birds using night flight to help achieve time- and energy-savings through ‘short cuts’ at barrier crossings, at times and locations when foraging opportunities are not available. Conclusions Overall, our results demonstrate the use of nocturnal flight and a high degree of individual plasticity in migration strategies on a circadian scale in a species generally considered to be a diurnal migrant. Nocturnal flights at barrier crossing may provide time and energy savings where foraging opportunities are low in an otherwise diurnal strategy. Future research should target how diel foraging and refueling strategies support nocturnal flights and barrier crossing in this and other diurnal species.

scholarly journals Distance Effects on Diversity and Abundance of the Flower Visitors of Ocimum kilimandscharicum in the Kakamega Forest Ecosystem

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hellen K. Mandela ◽  
Mugatsia H. Tsingalia ◽  
Mary Gikungu ◽  
Wilbur M. Lwande
Keyword(s):  
Species Diversity ◽  
Diversity Index ◽  
Land Use Changes ◽  
Species Abundance ◽  
Diversity Indices ◽  
Forest Edge ◽  
Flower Visitors ◽  
Kakamega Forest ◽  
Species Invasions ◽  
Wiener Diversity Index

Pollination is an important ecosystem service in the maintenance of biodiversity and most importantly in food production. Pollination is on the decline due to habitat loss, exotic species invasions, pollution, overharvesting, and land use changes. This study analyzed the abundance and diversity of flower visitors’ of Ocimum kilimandscharicum in Kakamega forest with increasing distance from the forest edge. Data were collected through direct observation and sweep netting. Six study sites were identified along two transects each 2.5 km long and labeled A to F. Distance in metres from the forest edge to each site was A=221, B=72, C=83, D=198, E=113, and F=50. Sampling was done from 7:30 am to 4:00 pm, three days in a week for five months consecutively. Diversity indices of different flower visitors were calculated using the Shannon-Wiener diversity index. One-way analysis of variance was used to compare differences between sites and a two-sample t-test was used to identify mean significant differences in species diversity between the closest and the furthest sites. A total of 645 individuals belonging to 35 species were captured from 4 families. The highest diversity was at site F (H’= 2.38) which was closest to the forest edge and the lowest diversity was from site A (H’=1.44) which was furthest from the forest edge. Distance from the forest edge significantly influenced species diversity (F(3, 20)=14.67, p=0.024). Distance from the forest edge also significantly influenced species abundance between the furthest sites A, D, and E and the nearest sites F, B, and C to the forest edge (t=4.177; p=0.0312) and species richness (t=3.2893; p=0.0187). This study clearly demonstrates that Ocimum kilimandscharicum flower visitors play essential roles in pollination and their higher number of visits translates into higher numbers of seeds set. Many of these pollinators are associated with the forest and hence the need to conserve the Kakamega forest as a source pool for pollinators.

scholarly journals A lognormal distribution of the lengths of terminal twigs on self-similar branches of elm trees

2017 ◽  
Vol 284 (1846) ◽  
pp. 20162395 ◽  
Author(s):  
Kohei Koyama ◽  
Ken Yamamoto ◽  
Masayuki Ushio
Keyword(s):  
Lognormal Distribution ◽  
Species Abundance ◽  
Self Similarity ◽  
Lognormal Distributions ◽  
Multiplicative Effect ◽  
Wide Range ◽  
Error Distributions ◽  
Species Abundance Distributions ◽  
Self Similar ◽  
Ulmus Davidiana

Lognormal distributions and self-similarity are characteristics associated with a wide range of biological systems. The sequential breakage model has established a link between lognormal distributions and self-similarity and has been used to explain species abundance distributions. To date, however, there has been no similar evidence in studies of multicellular organismal forms. We tested the hypotheses that the distribution of the lengths of terminal stems of Japanese elm trees ( Ulmus davidiana ), the end products of a self-similar branching process, approaches a lognormal distribution. We measured the length of the stem segments of three elm branches and obtained the following results: (i) each occurrence of branching caused variations or errors in the lengths of the child stems relative to their parent stems; (ii) the branches showed statistical self-similarity; the observed error distributions were similar at all scales within each branch and (iii) the multiplicative effect of these errors generated variations of the lengths of terminal twigs that were well approximated by a lognormal distribution, although some statistically significant deviations from strict lognormality were observed for one branch. Our results provide the first empirical evidence that statistical self-similarity of an organismal form generates a lognormal distribution of organ sizes.

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