scholarly journals POPULATION ECOLOGY OF THE NORTHERN SLIMY SALAMANDER (PLETHODON GLUTINOSUS) IN EAST-CENTRAL ILLINOIS

Author(s):  
John A. Crawford ◽  
Andrew R. Kuhns ◽  
Mathys J. Meyer

The importance of plethodontid salamanders in forested habitats has been recognized for decades and more recently plethodontids have been touted as a model taxon for monitoring ecosystem integrity and recovery. However, basic demographic data that are crucial to conservation and management plans are currently lacking for many species and regions. The objectives of our study were to characterize the population density, biomass, and capture success of a peripheral population of Plethodon glutinosus to provide a comparison for eastern populations and set a baseline for future monitoring of Midwestern populations. We estimated the population density of P. glutinosus at our site to be 0.41 salamanders/m2, with an estimated biomass of 0.70 g/m2. We did not find any evidence for temperature or precipitation affecting capture success. Our results showed that our density estimate falls within the range of other population ecology studies of Plethodon and sets a baseline for other peripheral Midwestern populations.

1987 ◽  
Vol 65 (6) ◽  
pp. 1317-1325 ◽  
Author(s):  
Lowell L. Getz ◽  
Joyce E. Hofmann ◽  
Brian J. Klatt ◽  
Louis Verner ◽  
F. Russell Cole ◽  
...  

Population densities of Microtus ochrogaster and M. pennsylvanicus were monitored from 1972 to 1986 in three habitats: alfalfa, bluegrass, and tallgrass prairie. Microtus ochrogaster displayed two apparent multiannual population cycles in alfalfa and bluegrass from 1972 to 1976; thereafter only annual (alfalfa) or erratic (bluegrass) fluctuations were apparent. Except for extremely high densities during 1984–1985, population fluctuations of M. ochrogaster in tallgrass were erratically low and there was no evidence of multiannual cycles. During 15 of 29 changes in population density of M. ochrogaster, the amplitude of fluctuations was more than 10-fold; 14 of these changes were preceded by marked population declines or very low densities the previous winter and spring. Microtus pennsylvanicus displayed annual fluctuations in abundance in alfalfa and bluegrass and was erratically high at all times in tallgrass. Only 7 of 32 population fluctuations of M. pennsylvanicus had amplitudes of at least 10-fold; in all 7 cases population density had been high the previous year. We conclude that distinct multiannual population cycles were not characteristic of either species in any habitat over the 14 years. Most previous assumptions of multiannual cycles in these species may be artifacts of short-term studies.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alessia Spada ◽  
Francesco Antonio Tucci ◽  
Aldo Ummarino ◽  
Paolo Pio Ciavarella ◽  
Nicholas Calà ◽  
...  

AbstractClimate seems to influence the spread of SARS-CoV-2, but the findings of the studies performed so far are conflicting. To overcome these issues, we performed a global scale study considering 134,871 virologic-climatic-demographic data (209 countries, first 16 weeks of the pandemic). To analyze the relation among COVID-19, population density, and climate, a theoretical path diagram was hypothesized and tested using structural equation modeling (SEM), a powerful statistical technique for the evaluation of causal assumptions. The results of the analysis showed that both climate and population density significantly influence the spread of COVID-19 (p < 0.001 and p < 0.01, respectively). Overall, climate outweighs population density (path coefficients: climate vs. incidence = 0.18, climate vs. prevalence = 0.11, population density vs. incidence = 0.04, population density vs. prevalence = 0.05). Among the climatic factors, irradiation plays the most relevant role, with a factor-loading of − 0.77, followed by temperature (− 0.56), humidity (0.52), precipitation (0.44), and pressure (0.073); for all p < 0.001. In conclusion, this study demonstrates that climatic factors significantly influence the spread of SARS-CoV-2. However, demographic factors, together with other determinants, can affect the transmission, and their influence may overcome the protective effect of climate, where favourable.


1992 ◽  
Vol 70 (5) ◽  
pp. 968-973 ◽  
Author(s):  
Charles M. Nixon ◽  
Lonnie P. Hansen ◽  
Paul A. Brewer ◽  
James E. Chelsvig

Stability and retention of parturition sites were examined for 17 white-tailed does (Odocoileus virginianus) radio-marked on an 800-ha forested area in Piatt County, east-central Illinois. Pre- and post-natal home range sizes were not significantly correlated with density of females, age of doe, litter size (postnatal range only), or sex of litter. As females aged, parturition sites moved closer to prenatal centers of home range activity (P < 0.02), and overlap of both pre- and post-natal home range boundaries increased in consecutive years (P < 0.001). Postnatal core areas of related females evidenced considerable overlap, whereas those of unrelated does were discrete. Breeding does used upland successional forests (< 60 years old) more than expected and bottomland forests less than expected (P < 0.05) as sites for parturition. Through seasonal movements, including migratory and dispersal behaviors, does in east-central Illinois, where forests are scarce, use all available sites suitable for parturition. Selection and retention of these parturition sites promote the development of matriarchal social groups, which ensures continued use of these sites by related females.


2012 ◽  
Vol 42 (6) ◽  
pp. 1050-1059 ◽  
Author(s):  
Lawrence M. Hanks ◽  
Jocelyn G. Millar ◽  
Judith A. Mongold-Diers ◽  
Joseph C.H. Wong ◽  
Linnea R. Meier ◽  
...  

We evaluated the attraction of native species of cerambycid beetles to blends of cerambycid pheromones and the host plant volatiles ethanol and α-pinene to determine whether such blends could be effective lures for detecting and monitoring multiple species. The complete six-component blend of pheromones included racemic 3-hydroxy-2-hexanone, 2,3-hexanediol isomers, (E)-6,10-dimethyl-5,9-undecadien-2-ol and the corresponding acetate, 2-(undecyloxy)-ethanol, and racemic 2-methyl-1-butanol. Bioassays in east-central Illinois captured 3070 cerambycid beetles of 10 species, including four species in the subfamily Cerambycinae ( Neoclytus acuminatus (Fabricius, 1775), Neoclytus mucronatus (Fabricius, 1775), Phymatodes lengi Joutel, 1911, and Xylotrechus colonus (Fabricius, 1775)) and six species in the subfamily Laminiae ( Aegomorphus modestus (Gyllenhal in Schoenherr, 1817), Astyleiopus variegatus (Haldeman, 1847), Astylidius parvus (LeConte, 1873), Graphisurus fasciatus (DeGeer, 1775), Lepturges angulatus (LeConte, 1852), and Monochamus carolinensis (Olivier, 1792)). Beetles were attracted to their pheromone components within the blend, with inhibition only evident in one species. Host plant volatiles synergized attraction for some species, and synergism usually was attributed to ethanol, with α-pinene enhancing attraction only for the pine specialist M. carolinensis. The optimal strategy for targeting a broad range of cerambycid species would be to bait traps with a blend of several pheromones plus ethanol and α-pinene because synergism by these plant volatiles is critical for some species, whereas strong inhibition is uncommon.


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