scholarly journals Knowledge gaps in demographic, spatial, and biological characteristics of Canadian at-risk plant species.

2021 ◽  
Author(s):  
Rebecca J. Parker
Keyword(s):  
At Risk ◽  
Missing Data ◽  
Poisson Distribution ◽  
Plant Species ◽  
Geographical Information ◽  
Biological Information ◽  
Missing Information ◽  
Abundance Distribution ◽  
Abundance Estimates ◽  
Species Specific

There are gaps in abundance, distribution, and biological information for many at-risk species, likely because of surveying difficulties. I outline these gaps for Canadian plant species and also suggest species-specific traits that hint at which species are difficult to assess in the field, therefore making them more likely to report missing data. A metaanalysis of COSEWIC listed plant species revealed that only 103 (60%) species had available status reports in 2013. Furthermore, 20% of those species had at least one missing population. Fifty-eight percent of missing information was attributable to missing abundance estimates, 24% percent to geographical information, and 18% to biological information. Finally, a Poisson distribution ANCOVA revealed no significant differences between species reporting uncertain populations and species not reporting such populations, nor in the amount of missing data they reported, with respect to any of the traits identified as potential indicators of surveying difficulty.

scholarly journals Knowledge gaps in demographic, spatial, and biological characteristics of Canadian at-risk plant species.

2021 ◽  
Author(s):  
Rebecca J. Parker
Keyword(s):  
At Risk ◽  
Missing Data ◽  
Poisson Distribution ◽  
Plant Species ◽  
Geographical Information ◽  
Biological Information ◽  
Missing Information ◽  
Abundance Distribution ◽  
Abundance Estimates ◽  
Species Specific

There are gaps in abundance, distribution, and biological information for many at-risk species, likely because of surveying difficulties. I outline these gaps for Canadian plant species and also suggest species-specific traits that hint at which species are difficult to assess in the field, therefore making them more likely to report missing data. A metaanalysis of COSEWIC listed plant species revealed that only 103 (60%) species had available status reports in 2013. Furthermore, 20% of those species had at least one missing population. Fifty-eight percent of missing information was attributable to missing abundance estimates, 24% percent to geographical information, and 18% to biological information. Finally, a Poisson distribution ANCOVA revealed no significant differences between species reporting uncertain populations and species not reporting such populations, nor in the amount of missing data they reported, with respect to any of the traits identified as potential indicators of surveying difficulty.

Missing Value Imputation Using ANN Optimized by Genetic Algorithm

2018 ◽  
Vol 5 (2) ◽  
pp. 41-57 ◽  
Author(s):  
Anjana Mishra ◽  
Bighnaraj Naik ◽  
Suresh Kumar Srichandan
Keyword(s):  
Genetic Algorithm ◽  
Missing Data ◽  
Data Entry ◽  
Missing Information ◽  
Missing Value ◽  
Need Analysis ◽  
Processing Data ◽  
Real World Applications ◽  
Long Time ◽  
Almost All

Missing value arises in almost all serious statistical analyses and creates numerous problems in processing data in databases. In real world applications, information may be missing due to instrumental errors, optional fields and non-response to some questions in surveys, data entry errors, etc. Most of the data mining techniques need analysis of complete data without any missing information and this induces researchers to develop efficient methods to handle them. It is one of the most important areas where research is being carried out for a long time in various domains. The objective of this article is to handle missing data, using an evolutionary (genetic) algorithm including some relatively simple methodologies that can often yield reasonable results. The proposed method uses genetic algorithm and multi-layer perceptron (MLP) for accurately predicting missing data with higher accuracy.

scholarly journals Emerging fungal pathogen of an invasive grass: Implications for competition with native plant species

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0237894
Author(s):  
Amy E. Kendig ◽  
Vida J. Svahnström ◽  
Ashish Adhikari ◽  
Philip F. Harmon ◽  
S. Luke Flory
Keyword(s):  
Invasive Species ◽  
Plant Species ◽  
Fungal Pathogen ◽  
Native Species ◽  
Grass Species ◽  
Leaf Spot Disease ◽  
Native Plant ◽  
Invasive Grass ◽  
Native Plant Species ◽  
Species Specific

Infectious diseases and invasive species can be strong drivers of biological systems that may interact to shift plant community composition. For example, disease can modify resource competition between invasive and native species. Invasive species tend to interact with a diversity of native species, and it is unclear how native species differ in response to disease-mediated competition with invasive species. Here, we quantified the biomass responses of three native North American grass species (Dichanthelium clandestinum, Elymus virginicus, and Eragrostis spectabilis) to disease-mediated competition with the non-native invasive grass Microstegium vimineum. The foliar fungal pathogen Bipolaris gigantea has recently emerged in Microstegium populations, causing a leaf spot disease that reduces Microstegium biomass and seed production. In a greenhouse experiment, we examined the effects of B. gigantea inoculation on two components of competitive ability for each native species: growth in the absence of competition and biomass responses to increasing densities of Microstegium. Bipolaris gigantea inoculation affected each of the three native species in unique ways, by increasing (Dichanthelium), decreasing (Elymus), or not changing (Eragrostis) their growth in the absence of competition relative to mock inoculation. Bipolaris gigantea inoculation did not, however, affect Microstegium biomass or mediate the effect of Microstegium density on native plant biomass. Thus, B. gigantea had species-specific effects on native plant competition with Microstegium through species-specific biomass responses to B. gigantea inoculation, but not through modified responses to Microstegium density. Our results suggest that disease may uniquely modify competitive interactions between invasive and native plants for different native plant species.

scholarly journals Interspecific differences of stridulatory signals in three species of bark beetles from the genus Polygraphus Er. (Coleoptera: Curculionidae, Scolytinae) inhabiting the island of Sakhalin

2019 ◽  
Author(s):  
Ivan Andreevich Kerchev
Keyword(s):  
Host Plant ◽  
Plant Species ◽  
Bark Beetles ◽  
Acoustic Signals ◽  
Interval Number ◽  
Host Plant Species ◽  
Interspecific Differences ◽  
Species Specific ◽  
Conspecific Interactions

Stridulatory signals are involved in conspecific interactions between bark beetles (Coleoptera: Curculionidae, Scolytinae). In this study, we compared the qualitative profiles of acoustic signals in three species from the genus Polygraphus Er. Sympatry can be periodically observed in two of them – P. proximus and P. subopacus. Sporadically they occur on the same plants. P. nigrielytris colonize distinctly different host plant species; however, on the island of Sakhalin it inhabits the same biotopes. The purpose of the study is to identify species-specific parameters and the extent of differences in stridulatory signals of these species. Airborne signals produced during the contact of males of the same species were experimentally recorded. Among tested parameters of stridulatory signals, as the most species-specific were noted: chirp duration, interchirp interval, number of tooth-strikes per chirp, and intertooth-strike interval.

scholarly journals Species-specific effects of passive warming in an Antarctic moss system

2019 ◽  
Vol 6 (11) ◽  
pp. 190744 ◽  
Author(s):  
Hannah M. Prather ◽  
Angélica Casanova-Katny ◽  
Andrew F. Clements ◽  
Matthew W. Chmielewski ◽  
Mehmet A. Balkan ◽  
...  
Keyword(s):  
Plant Species ◽  
Fungal Biomass ◽  
Trophic Levels ◽  
Moss Species ◽  
Abiotic Environment ◽  
Invertebrate Communities ◽  
Passive Warming ◽  
Specific Effects ◽  
Species Specific ◽  
Antarctic Moss

Polar systems are experiencing rapid climate change and the high sensitivity of these Arctic and Antarctic ecosystems make them especially vulnerable to accelerated ecological transformation. In Antarctica, warming results in a mosaic of ice-free terrestrial habitats dominated by a diverse assemblage of cryptogamic plants (i.e. mosses and lichens). Although these plants provide key habitat for a wide array of microorganisms and invertebrates, we have little understanding of the interaction between trophic levels in this terrestrial ecosystem and whether there are functional effects of plant species on higher trophic levels that may alter with warming. Here, we used open top chambers on Fildes Peninsula, King George Island, Antarctica, to examine the effects of passive warming and moss species on the abiotic environment and ultimately on higher trophic levels. For the dominant mosses, Polytrichastrum alpinum and Sanionia georgicouncinata , we found species-specific effects on the abiotic environment, including moss canopy temperature and soil moisture. In addition, we found distinct shifts in sexual expression in P . alpinum plants under warming compared to mosses without warming, and invertebrate communities in this moss species were strongly correlated with plant reproduction. Mosses under warming had substantially larger total invertebrate communities, and some invertebrate taxa were influenced differentially by moss species. However, warmed moss plants showed lower fungal biomass than control moss plants, and fungal biomass differed between moss species. Our results indicate that continued warming may impact the reproductive output of Antarctic moss species, potentially altering terrestrial ecosystems dynamics from the bottom up. Understanding these effects requires clarifying the foundational, mechanistic role that individual plant species play in mediating complex interactions in Antarctica's terrestrial food webs.

scholarly journals Evidence of within-species specialization by soil microbes and the implications for plant community diversity

2019 ◽  
Vol 116 (15) ◽  
pp. 7371-7376 ◽  
Author(s):  
Jenalle L. Eck ◽  
Simon M. Stump ◽  
Camille S. Delavaux ◽  
Scott A. Mangan ◽  
Liza S. Comita
Keyword(s):  
Microbial Community ◽  
Seed Dispersal ◽  
Plant Species ◽  
Plant Community ◽  
Plant Communities ◽  
Soil Microbial Community ◽  
Soil Microbes ◽  
Wild Plant ◽  
Soil Microbial ◽  
Species Specific

Microbes are thought to maintain diversity in plant communities by specializing on particular species, but it is not known whether microbes that specialize within species (i.e., on genotypes) affect diversity or dynamics in plant communities. Here we show that soil microbes can specialize at the within-population level in a wild plant species, and that such specialization could promote species diversity and seed dispersal in plant communities. In a shadehouse experiment in Panama, we found that seedlings of the native tree species, Virola surinamensis (Myristicaceae), had reduced performance in the soil microbial community of their maternal tree compared with in the soil microbial community of a nonmaternal tree from the same population. Performance differences were unrelated to soil nutrients or to colonization by mycorrhizal fungi, suggesting that highly specialized pathogens were the mechanism reducing seedling performance in maternal soils. We then constructed a simulation model to explore the ecological and evolutionary consequences of genotype-specific pathogens in multispecies plant communities. Model results indicated that genotype-specific pathogens promote plant species coexistence—albeit less strongly than species-specific pathogens—and are most effective at maintaining species richness when genetic diversity is relatively low. Simulations also revealed that genotype-specific pathogens select for increased seed dispersal relative to species-specific pathogens, potentially helping to create seed dispersal landscapes that allow pathogens to more effectively promote diversity. Combined, our results reveal that soil microbes can specialize within wild plant populations, affecting seedling performance near conspecific adults and influencing plant community dynamics on ecological and evolutionary time scales.

scholarly journals Will I stay or will I go? Plant species‐specific response and tolerance to high land‐use intensity in temperate grassland ecosystems

2019 ◽  
Vol 30 (4) ◽  
pp. 674-686 ◽  
Author(s):  
Verena Busch ◽  
Valentin H. Klaus ◽  
Deborah Schäfer ◽  
Daniel Prati ◽  
Steffen Boch ◽  
...  
Keyword(s):  
Land Use ◽  
Plant Species ◽  
Temperate Grassland ◽  
Specific Response ◽  
Land Use Intensity ◽  
Grassland Ecosystems ◽  
Species Specific

A multifrequency method to classify and evaluate fisheries acoustics data

2006 ◽  
Vol 63 (10) ◽  
pp. 2225-2235 ◽  
Author(s):  
J Michael Jech ◽  
William L Michaels
Keyword(s):  
Clupea Harengus ◽  
Biological Information ◽  
Classification Algorithms ◽  
Atlantic Herring ◽  
Population Abundance ◽  
Acoustic Data ◽  
Video Images ◽  
Abundance Estimates ◽  
Fisheries Acoustics ◽  
Acoustic Surveys

Acoustic surveys have been conducted on Georges Bank from 1998 to present to estimate Atlantic herring (Clupea harengus) population abundance. Acoustic data were collected with a 12 or 18, 38, and 120 kHz Simrad EK500 scientific echo sounder. A pelagic trawl and underwater video images were used to collect biological information and to verify the species composition of acoustic backscatter. A multifrequency classification method was developed to improve the efficiency and accuracy of classifying species from acoustic echograms. In this method, a volume backscatter (Sv) threshold was applied equivalently to all echograms, and then a composite echogram was created based on which frequencies had Sv greater than or less than the Sv threshold. The results of this method were compared with the standard method of visually scrutinizing regions, and metrics were developed to evaluate the accuracy of classification algorithms relative to current methods, as well as to assess the effects of classification methods on population abundance estimates. In general, this method matched visually scrutinized Atlantic herring regions, but with consistent biases in classifying 38 kHz backscatter. The metrics highlighted spatial and temporal changes in the acoustic landscape, which may be indicative of intra- and inter-annual biological changes.

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