•A study on community phenophases of alpine grassland along an elevation gradient.•Nonlinear responses of community phenophases to continued warming or cooling.•Changes in plant diversity of ...different functional groups cause nonlinear responses of community phenophases.
Lack of understanding of how plant diversity of different flowering functional groups mediates response patterns of community phenophases to climate change limits our ability to predict future phenology. We used reciprocal transplant experiments across four elevations (i.e., 3200, 3400, 3600 and 3800 m) on the Tibetan Plateau for three years to investigate how temperature change (i.e., warming and cooling) affects the temperature responses of plant functional diversity and community phenophases and their relationships. Our results showed that a nonlinear regression model was the best fitting model for most temperature responses of SDI and community phenophases under warming and cooling. Meanwhile, decreased diversity of early-spring flowering (ESF) and mid-summer flowering (MSF) groups under warming, and increased diversity of ESF under cooling, reduced temperature sensitivities of nearly all community phenophases. These results illustrate that changes in plant diversity should be taken into account when predicting the response pattern of temperature sensitivities of community phenophases.
Soil respiration is the largest carbon (C) flux from terrestrial ecosystems into the atmosphere. Accurate estimates of the magnitude and distribution of soil respiration are critically important to ...models of global C cycling and predictions of future climate change. One of the greatest challenges to accurate large-scale estimation of soil respiration is its great spatial heterogeneity at the site level. Our study explored how soil respiration varies in space and the drivers that lead to this variance in a natural subtropical evergreen broadleaf forest in Southern China. We conducted a two-year soil respiration measurement for 168 randomly selected sampling points in a 4 ha plot. We measured the spatial variance of soil respiration and tested its correlation to a variety of abiotic and biotic factors including topography, aboveground plant community structure, soil environmental factors, soil organic matter, and microbial community structure. We found that soil respiration was highly varied across the study plot, with a spatial variation coefficient (CV) of 32.75%. The structural equation modeling (SEM) analysis showed that elevation influenced tree species diversity, productivity, and soil water content, which in turn affected soil respiration via soil C content, clay content, fungal:bacterial ratio, annual litterfall, and fine root biomass. 31% of the total spatial variation of soil respiration was accounted for in the SEM, mostly by elevation, soil C content, annual litterfall biomass, tree species diversity as estimated by the Simpson's index, and soil water content, with standardized total effects of 0.31, −0.31, 0.29, 0.19, and −0.18, respectively. Our data demonstrated that soil respiration was highly spatially varied at the fine scale, and was primarily regulated by factors of topography and plant community structure. More studies investigating the spatial variation of soil respiration are therefore needed to better understand and assess terrestrial ecosystem C cycling.
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•Soil respiration is spatially varied in a subtropical forest with a CV of 33%.•Elevation has a positive influence on soil respiration at the fine scale.•High plant community productivity and low diversity favor soil respiration.
Using geographic information systems and digital elevation data, we investigate the hypothesis that the imperial Chinese state manipulated provincial borders to weaken the autonomy of Chinese ...regions. We find that China's present-day provincial borders, whose origin can be traced back to the thirteenth century, are highly misaligned with respect to physiographic features along China's North-South political fault line. Elsewhere, in regions that historically did not pose a fundamental threat to central authority, the degrees of misalignment are considerably lower. We interpret these findings as evidence of strategic manipulation of provincial boundaries. Our findings cast light on the spatial distribution of boundary misalignment and help identify the areas where the socioeconomic ramifications of misalignment—such as recurring cross-border pollution and inter-community disputes—are likely to be present.
•Large states with heterogeneous populations have incentives to divide and rule.•China's provincial and physiographic boundaries are not always aligned.•The degree of misalignment is highest along China's North-South divide.•Misalignment is less severe in strategically less pivotal areas.•The spatial patterns reflect the need to check centrifugal tendencies in history.
Here, we assessed the utility of a polymerase chain reaction-based open reading frame typing assay for investigating the clonality of Clostridioides difficile isolates. This assay has a higher ...discriminatory power than multi-locus sequence typing for molecular epidemiological analysis of C. difficile isolates and can provide additional information about toxin genotypes.
•POT method can determine C. difficile toxin genotype.•POT method exhibits higher discriminatory power than MLST for C. difficile typing.•POT method is a useful tool for the epidemiological investigations of C. difficile.
Students learning the skills of science benefit from opportunities to move between the scientific problems and questions they confront and the mathematical tools available to answer the questions and ...solve the problems. Indeed, students learn science best when they are actively engaged in pursuing answers to authentic and relevant questions. We present an activity teachers can use in the classroom to introduce the concepts of species richness and diversity. We break down the history and logic behind the two primary statistical tools ecologists use to quantify species diversity: Simpson's and Shannon's diversity indices. With hypothetical data, we show how students can learn about and practice the calculations. We then describe an activity where students collect authentic ecological data with pitfall traps while learning some arthropod systematics and practicing their newly acquired quantitative reasoning skills, all within the context of edge effect ecology and habitat conservation. The entire activity reinforces for students how interesting and helpful mathematical models and quantitative reasoning in science can be for understanding biological phenomena, but also for generating more questions, and for designing additional data-collection techniques and experiments.
Olopade OA, Rufai OP. 2014. Composition, abundance and diversity of the Family Cichlidae in Oyan Dam, Ogun State, Nigeria. Biodiversitas 15: 195-199.This study was conducted to determine status of ...the family Cichlidae in Oyan Dam, Nigeria, during the wetand dry seasons of 2011. Samples were collected using multi-mesh gillnets ranging between 30 mm to 80 mm. Simpson's DiversityIndex was used to determine the species richness, while dominance and evenness were given by Shannon's index. A total of 547individuals were caught from Imala (S1) and Ibaro (S2) sites of the dam. Species collected include Sarotherodon galilaeus (42.60%),Oreochromis niloticus (17.92%), Tilapia zillii (25.41%), Hemichromis fasciatus (10.61%) and Tilapia mariae (3.48%). Juveniles andsub-adults and adults were among the catch, the sizes were as big as 12.85±0.29cm SL, 109.22±6.00g BW in Tilapia zillii and small as6.09±0.05cm SL and 8.07±0.15g BW in Hemichromis fasciatus. The diversity indexes showed that the diversity of Cichlids was lowerin the two sites observed in Oyan Dam. The estimates of diversity indexes showed lower value for site 1 (0.284) than for site 2 (0.294);Simpson's diversity index was 0.716 for site 1 and 0.703 for site 2 while reciprocal indexes for site 1(3.521) was slightly lower than site2 (3.367). Shannon-Wiener’s Index recorded in the site 1 (1.36) was slightly lower than site 2 (1.37). Pielou’s Index value recorded forsite 1 was 0.845 and 0.852 for site 2. Sarotherodon galilaeus, Oreochromis niloticus, Tilapia zillii and Tilapia mariae exhibited apositive allometric growth pattern while only Hemichromis fasciatus showed a negative allometric growth.
In island ecosystems, reptiles play diverse ecological roles as a result of niche broadening, which increases potential niche overlap between species. Ecological niche partitioning is a means of ...reducing direct competition between coexisting species and differences in habitat use among island gecko species have been suggested as a by‐product of specialization to feeding on certain resources. Here, we examine modes and drivers of niche partitioning of two endemic species of Phelsuma gecko (Phelsuma sundbergi and Phelsuma astriata) in relict native palm forest in the Seychelles to further understanding of congeneric reptile co‐existence in native habitats. Phelsuma abundance, microhabitat use and habitat composition were quantified in different macrohabitat types. P. sundbergi showed a clear preference for habitat dominated by the coco de mer palm, Lodoicea maldivica and a strong association with male individuals of this dioecious species. P. astriata density increased significantly with arboreal biodiversity but did not display a relationship with a specific tree type. High levels of resource segregation were determined along the microhabitat axis, based on differential tree preference. Our results suggest that P. sundbergi and P. astriata may have evolved to co‐exist in this habitat type through partitioning of microhabitat as members of a divergent specialist/generalist assemblage determined by consumption of L. maldivica pollen by P. sundbergi. Our findings concur with the hypothesis that differences in habitat use among island reptiles are a by‐product of trophic specialization and support the conservation of native habitat for maintenance of reptile diversity.
Brucellosis is the most common bacterial zoonosis in the world. Multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) is a molecular method for genotyping bacterial species. Brucella ...abortus biovar I was isolated from most of the brucellosis-suspected patients in Korea. This study was conducted to investigate the ability of various MLVA primers that are used for molecular typing B. abortus isolates and for analyzing their epidemiological data.
A total of 80 human isolates of B. abortus biovar I isolated from human patients and the reference strain were used for MLVA. Genetic diversity was determined by calculating the Simpson's diversity index (DI) of each VNTR locus. The Brucella strains were subcultured 30 times to determine the stability of each locus. The DNA of the strains cultivated in each passage was extracted and subjected to MLVA for further investigation.
The 15 VNTR loci were selected based on high DI values. The DIs of the 15 VNTR loci showed considerable discrimination power ranging from 59% for Bruce 43 to 87% for Bruce 22. Bruce 09, Bruce 11, Bruce 16, Bruce 42, and Bruce 43 were confirmed to remain stable in vitro among the 15 VNTR loci selected.
The results of this study suggest that the five loci subsets may be a useful epidemiological tool for investigating B. abortus biovar 1 outbreak.
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