Patterns of Plant Invasions: A Case Example in Native Species Hotspots and Rare Habitats

Land managers require landscape-scale information on where exotic plant species have successfully established, to better guide research, control, and restoration efforts. We evaluated the vulnerability of various habitats to invasion by exotic plant species in a 100,000 ha area in the southeast corner of Grand Staircase-Escalante National Monument, Utah. For the 97 0.1-ha plots in 11 vegetation types, exotic species richness (log₁₀) was strongly negatively correlated to the cover of cryptobiotic soil crusts (r = −0.47, P < 0.001), and positively correlated to native species richness (r = 0.22, P < 0.03), native species cover (r = 0.23, P < 0.05), and total nitrogen in the soil (r = 0.40, P < 0.001). Exotic species cover was strongly positively correlated to exotic species richness (r = 0.68, P < 0.001). Only 6 of 97 plots did not contain at least one exotic species. Exotic species richness was particularly high in locally rare, mesic vegetation types and nitrogen rich soils. Dry, upland plots (n = 51) had less than half of the exotic species richness and cover compared to plots (n = 45) in washes and lowland depressions that collect water intermittently. Plots dominated by trees had significantly greater native and exotic species richness compared to plots dominated by shrubs. For the 97 plots combined, 33% of the variance in exotic species richness could be explained by a positive relationship with total plant cover, and negative relationships with the cover of cryptobiotic crusts and bare ground. There are several reasons for concern: (1) Exotic plant species are invading hot spots of native plant diversity and rare/unique habitats. (2) The foliar cover of exotic species was greatest in habitats that had been invaded by several exotic species.(3) Continued disturbance of fragile cryptobiotic crusts by livestock, people, and vehicles may facilitate the further invasion of exotic plant species. This revised version was published online in July 2006 with corrections to the Cover Date.     

Life-history Habitat Matching in Invading Non-native Plant Species

We briefly reviewed the literature on habitat matching in invading non-native plant species. Then we hypothesized that the richness and cover of native annual and perennial plant species integrate complex local information of vegetation and soils that would help to predict invasion success by similarly adapted non-native plant species. We tested these ‘life-history habitat matching’ relationships in 603 0.1-ha plots, including 294 plots in Colorado, which were relatively high for the cover of native perennial plant species, and for 309 0.1-ha plots in southern Utah, which were relatively high in the cover of native annual plant species. We found strong positive relationships between the richness and foliar cover for both native and non-native species, whether they were annual or perennial species (0.34 > r ² < 0.53; P < 0.0001). We also found significant positive relationships between the cover of native annual species at a site and the richness (r ² = 0.13; P < 0.0001) and the foliar cover (r ² = 0.06; P < 0.0001) of non-native annual species. The proportion of non-native annual species in the flora of a plot also increased significantly with the foliar cover of native annual species. Conversely, the richness and cover of non-native annual species were significantly negatively associated with the foliar cover of native perennial species (r ² = 0.05 and 0.06, respectively; P < 0.0001). The cover of non-native annual or perennial species was not significantly correlated with soil texture variables, %N, or %C. We conclude that there may be a high degree of life-history habitat matching by non-native annual species in these study sites. Information on native annual and perennial species richness and cover may help characterize the complex soils, climate, and disturbance environment in which similarly adapted non-native plant species establish and gain foliar cover.     

Do secondary compounds inhibit microbial- and insect-mediated leaf breakdown in a tropical rainforest stream, Costa Rica?

We examined the hypothesis that high concentrations of secondary compounds in leaf litter of some tropical riparian tree species decrease leaf breakdown by inhibiting microbial and insect colonization. We measured leaf breakdown rates, chemical changes, bacterial, fungal, and insect biomass on litterbags of eight species of common riparian trees incubated in a lowland stream in Costa Rica. The eight species spanned a wide range of litter quality due to varying concentrations of nutrients, structural and secondary compounds. Leaf breakdown rates were fast, ranging from 0.198 d⁻¹ (Trema integerrima) to 0.011 d⁻¹ (Zygia longifolia). Processing of individual chemical constituents was also rapid: cellulose was processed threefold faster and hemicellulose was processed fourfold faster compared to similar studies in temperate streams. Leaf toughness (r = −0.86, P = 0.01) and cellulose (r = −0.78, P = 0.02) were the physicochemical parameters most strongly correlated with breakdown rate. Contrary to our initial hypothesis, secondary compounds were rapidly leached (threefold faster than in temperate studies), with all species losing all secondary compounds within the first week of incubation. Cellulose was more important than secondary compounds in inhibiting breakdown. Levels of fungal and bacterial biomass were strongly correlated with breakdown rate (fungi r = 0.64, P = 0.05; bacteria r = 0.93, P < 0.001) and changes in structural compounds (lignin r = −0.55, P = 0.01). Collector−gatherers were the dominant functional group of insects colonizing litterbags, in contrast to temperate studies where insect shredders dominate. Insect biomass was negatively correlated with breakdown rate (r = −0.70, P = 0.02), suggesting that insects did not play an important role in breakdown. Despite a wide range of initial concentrations of secondary compounds among the eight species used, we found that secondary compounds were rapidly leached and were less important than structural compounds in determining breakdown rates. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Bird abundance and species richness on Florida lakes: influence of trophic status,lake morphology,and aquatic macrophytes

Data from 46 Florida lakes were used to examine relationships between bird abundance (numbers and biomass) and species richness, and lake trophic status, lake morphology and aquatic macrophyte abundance. Average annual bird numbers ranged from 7 to 800 birds km^–2 and bird biomass ranged from 1 to 465 kg km^–2. Total species richness ranged from 1 to 30 species per lake. Annual average bird numbers and biomass were positively correlated to lake trophic status as assessed by total phosphorus (r = 0.61), total nitrogen (r = 0.60) and chlorophyll a (r = 0.56) concentrations. Species richness was positively correlated to lake area (r = 0.86) and trophic status (r = 0.64 for total phosphorus concentrations). The percentage of the total annual phosphorus load contributed to 14 Florida lakes by bird populations was low averaging 2.4%. Bird populations using Florida lakes, therefore, do not significantly impact the trophic status of the lakes under natural situations, but lake trophic status is a major factor influencing bird abundance and species richness on lakes. Bird abundance and species richness were not significantly correlated to other lake morphology or aquatic macrophyte parameters after the effects of lake area and trophic status were accounted for using stepwise multiple regression. The lack of significant relations between annual average bird abundance and species richness and macrophyte abundance seems to be related to changes in bird species composition. Bird abundance and species richness remain relatively stable as macrophyte abundance increases, but birds that use open-water habitats (e.g., double-crested cormorant, Phalacrocorax auritus) are replaced by species that use macrophyte communities (e.g., ring-necked duck, Aythya collaris).     

Regulation of b- and a-Glycolytic Activities in the Sediments of a Eutrophic Lake

Temporal changes in α-and β-glucosidase activities, dissolved organic matter content, and bacterial biomass were studied in the superficial sediment layer of a eutrophic lake during the period of anoxia. The mean α-and β-glucosidase activities were 30.7±11.0 and 15.1±6.2 nmol h⁻¹ g⁻¹ of dry sediment, respectively. The specifc β-glucosidase activity seemed to be stimulated by carbohydrates (r=0.80, P<0.05), whereas the specifc α-glucosidase activity was negatively correlated with the dissolved protein concentration (r=−0.72, P<0.10). To test the effect of organic matter on hydrolytic activities under controlled conditions, changes in specific activities were studied in relation to the concentrations of different types of organic matter: phytoplankton, polymers (proteins, cellobiose, and starch) and monomers (glucose and amino acids). The specifc α-and β-glucosidase activities were strongly induced by their natural substrates (starch and cellobiose, respectively) (P<0.05) and were not inhibited by glucose. Proteins inhibited these activities (P<0.05), whereas supplementation with amino acids had no effect on specifc glycolytic activities.     

Plant communities and landscape diversity along a Canadian Arctic river

Abstract. We analysed the structure and diversity of the vegetation along an Arctic river to determine the relationship between species richness and plant community structure. We examined whether variation in species richness along the corridor is structured as (1) an increase in the number of communities due to increasing landscape heterogeneity, (2) an increase in the floristic distinctiveness (β-diversity) of communities, or (3) an increase in within-community richness (α-diversity) as species-poor communities are replaced by species-rich communities. We described 24 community types and analysed the relationship between site vascular species richness (γ-diversity) and β-diversity, α-diversity, site environmental heterogeneity, and the number of distinct plant communities. We also measured diversity patterns of vascular, bryophyte, and lichen species within communities and examined their relationship to community-level estimates of environmental factors. We found that an increase in site species richness correlated with an increase in the number of communities (r²= 0.323, P= 0.0173) and β-diversity (r²= 0.388, P= 0.0075), rather than an increase in the α-diversity of individual communities. Moisture and pH controlled most of the differences in composition between communities. Measures of species richness and correlations with moisture and pH within communities differed among vascular, bryophyte, and lichen species. Bryophyte richness was positively correlated with moisture (r²= 0.862, P= 0.0010) and lichen richness was negatively correlated with moisture (r²= 0.809, P= 0.0031). Vascular plants had a peak in richness at pH 6.5 (r²= 0.214, P < 0.0001). We conclude that site variation in vascular richness in this region is controlled by landscape heterogeneity, and structured as variation in the number and distinctiveness of recognizable plant communities.     

Relationship between total phenols and aflatoxin production of peanut genotypes under end-of-season drought conditions

Aflatoxin contamination of peanut caused by Aspergillus flavus, is a major problem in the rainfed agriculture in the semi-arid tropics associated with end-of-season drought stress. The present study was taken up to investigate the relationship between total phenol content of peanut leaves and kernels with aflatoxin content. Moisture stress was imposed from 60DAS to till harvest under rainout shelters and the data was recorded at the end-of-season drought conditions during kharif, 2003. Results revealed that, among the twenty one peanut genotypes tested, J-11, IC-48, ICGV 89104 and ICGS-76 had consistently low aflatoxin levels (<25 ppb) and high total phenols in leaves and kernels (>1,300 μg g⁻¹) at harvest under end-of-season drought conditions. Aflatoxin production was negatively correlated with total phenols in kernels (r ² = −0.42, P < 0.05) and leaves (r ² = −0.37, P < 0.05). No consistent relationship was observed between kernel infection and aflatoxin production.     

Fine-root mass, growth and nitrogen content for six tropical tree species

Although fine roots might account for 50% of the annual net primary productivity in moist tropical forests, there are relatively few studies of fine-root dynamics in this biome. We examined fine-root distributions, mass, growth and tissue N and C concentrations for six tree species established in 16-year-old plantations in the Caribbean lowlands of Costa Rica in a randomized-block design (n = 4). The study included five native species (Hyeronima alchorneoides, Pentaclethra macroloba, Virola koschnyi, Vochysia ferruginea and Vochysia guatemalensis) and one exotic (Pinus patula). Under all species >60% of the total fine-root mass to 1 m deep was located in the uppermost 15 cm of the soil. Fine-root live biomass and necromass (i.e., the mass of dead fine-roots) varied significantly among species but only within the uppermost 15 cm, with biomass values ranging from 182 g m⁻² in Pinus to 433 g m⁻² in Hyeronima plots, and necromass ranging from 48 g m⁻² in Pinus to 183 g m⁻² in Virola plots. Root growth, measured using ingrowth cores, differed significantly among species, ranging from 304 g m⁻² year⁻¹ in Pinus to 1,308 g m⁻² year⁻¹ in Hyeronima. These growth rates were one to five times those reported for moist temperate areas. Turnover rates of fine-root biomass ranged from 1.6 to 3.0 year⁻¹ in Virola and Hyeronima plots, respectively. Fine-root biomass was significantly and positively correlated with fine-root growth (r = 0.79, P < 0.0001), but did not correlate with fine-root turnover (r = 0.10, P = 0.20), suggesting that fine-root accumulation is a function of growth rate rather than mortality. Fine-root longevity was not correlated (r = 0.20, P = 0.34) and growth was negatively correlated with root N concentration across species (r = −0.78, P < 0.0001), contrary to reported trends for leaves, perhaps because N was relatively abundant at this site.     

Diversity and geographic distribution of <Emphasis Type="Italic">Chlorococcales</Emphasis> (<Emphasis Type="Italic">Chlorophyceae</Emphasis>) in contrasting lakes along a latitudinal transect in Argentinean Patagonia

The present study focuses on the geographic distribution and biodiversity of the Chlorococcales in Patagonian lakes, covering a latitudinal transect. Two different approaches are considered (a) a review of the historical records of Chlorococcales in Patagonia and (b) the analysis of the morphology-based species diversity, ecological remarks, and geographic distribution of the chlorococcalean species recorded in 33 aquatic environments during surveys 2007 and 2008. A total of 308 chlorococcalean species were recorded throughout a 60-year period in Patagonian freshwater systems, encountering the highest chlorococcalean richness in lakes and shallow lakes located in the more intensively sampled areas. In our surveys 2007–2008, 72 chlorococcalean taxa were registered, among which 80% are worldwide distributed, about 19% are restricted to cold temperate areas in both hemispheres and one species (Pediastrum patagonicum) is one of the taxa probably endemic for Patagonia. The chlorococcalean richness in relation to the environmental factors, revealed that it is directly correlated with the trophic status of the water bodies (chl a: r = 0.52 and DIN: r = 0.47; P < 0.05). The latitude was inversely correlated with the species richness (r = −0.40; P < 0.05), and the chlorococcalean biodiversity of the Andean lakes (mean value: 3.64) was significantly lower (P = 0.0022) than that of the lakes from the Patagonian Plateau (mean value: 9.62). In this study we observed a decreasing trend in the biodiversity of Chlorococcales with increasing latitude, which fits in the existing ecological pattern described for different groups of organisms.     

Plasma zinc, copper, leptin, and body composition are associated in elite female judo athletes

This study evaluated levels of plasma zinc, copper, and leptin, body composition, and their relationship in nine elite female judo athletes under two different training conditions. Body composition and biochemical measurements (hematological indexes, plasma zinc, plasma copper, and plasma leptin) were analyzed 24 h after intense training and following a 5-d period without training (no-training). Plasma leptin and plasma zinc increased with no-training. Plasma zinc correlated negatively with percent fat mass (r=−0.62; r=0.05) and positively with plasma leptin (r=0.83; p=0.002) in the no-training condition Plasma copper did not change during the study and correlated positively with plasma leptin (r=0.66; p=0.05) and with percent fat mass (r=0.80; p=0.007) after training. Percent fat mass was associated negatively with plasma zinc (r=−0.62; p=0.05) in the no-training condition. Moreover percent fat mass was negatively associated with the Zn/Cu plasma ratio under both training conditions (r<−0.78, p<0.001). These results are consistent with the possible function of zinc as a lipid-mobilizing factor and of copper as a limiting factor in energy metabolism.     

Relationship between plant species diversity and soil microbial functional diversity along a longitudinal gradient in temperate grasslands of Hulunbeir,Inner Mongolia,China

Numerous experiments have been established to examine the effect of plant diversity on the soil microbial community. However, the relationship between plant diversity and microbial functional diversity along broad spatial gradients at a large scale is still unexplored. In this paper, we examined the relationship of plant species diversity with soil microbial biomass C, microbial catabolic activity, catabolic diversity and catabolic richness along a longitudinal gradient in temperate grasslands of Hulunbeir, Inner Mongolia, China. Preliminary detrended correspondence analysis (DCA) indicated that plant composition showed a significant separation along the axis 1, and axis 1 explained the main portion of variability in the data set. Moreover, DCA-axis 1 was significantly correlated with soil microbial biomass C (r = 0.735, P = 0.001), microbial catabolic activity (average well color development; r = 0.775, P < 0.001) and microbial functional diversity (catabolic diversity: r = 0.791, P < 0.001 and catabolic richness: r = 0.812, P < 0.001), which suggested thatsome relationship existed between plant composition and the soil microbial community along the spatial gradient at a large scale. Soil microbial biomass C, microbial catabolic activity, catabolic diversity and catabolic richness showed a significant, linear increase with greater plant species richness. However, many responses that we observed could be explained by greater aboveground plant biomass associated with higher levels of plant diversity, which suggested that plant diversity impacted the soil microbial community mainly through increases in plant production.     

Low IGF-1 levels are associated with cardiovascular risk factors in haemodialysis patients

Cardiovascular diseases (CVD) constitute a significant risk and may, in part, explain the high morbidity and mortality rates among haemodialysis (HD) patients. Several studies have implicated reduced insulin like growth factor (IGF-1) levels in the development of CVD. However, it is not clear whether IGF-1, and its relationship with other hormones such as leptin, insulin, and growth hormone (GH), as well as anthropometric variables may explain the high incidence of vascular complications in chronic kidney disease (CKD) patients. This study was designed to measure total serum IGF-1, leptin, insulin and GH levels in CKD patients and in age-matched control subjects and to elucidate the relationship between IGF-1 and GH, leptin, and insulin as well as other known aetiological risk factors for CVD including blood pressure, body mass index (BMI), and age. The study consisted of 50 CKD patients [36 M and 14 F; mean age; 41.8 ± 10.3 years) on maintenance haemodialysis and 50 healthy control subjects (36 M and 14 F; mean age 41.6 ± 10.2 years) matched for age and sex. None of the subject among patients and controls reported either smoking or history of diabetes mellitus. The circulating levels of IGF-1 were significantly lower (P < 0.001) in both male and female patients compared to the control subjects. Moreover, IGF-1 was strongly and inversely correlated with both systolic blood pressure (SBP) (r = −0.360; P < 0.01) and diastolic blood pressure (DBP) (r = −0.512; P < 0.001) in the CKD group, and when the two groups were combined SBP (r = −0.396; P < 0.001) and DBP (r = −0.296; P < 0.01). When adjusted for age, the correlation was more significant, however, when adjusted for BMI no significant correlation was observed between IGF-1 and blood pressure. IGF-1 was inversely correlated with age (r = −0.367; P < 0.01) and BMI (r = −0.310; P < 0.05) in the control group, but not the patient group. In controls and patients, respectively, a positive correlation between leptin and BMI (r = 0.358; P < 0.01; r = 0.640, P < 0.001) was observed. The results show that circulating levels of IGF-1 were significantly lower in CKD patients as compared to healthy normal subjects and were inversely correlated with SBP and DBP independent of age, but not BMI indicative of a strong relationship between cardiovascular risk factors and low IGF-1 levels. Although, the data do not clearly indicate low IGF-1 levels as a cause or an effect of these cardiovascular risk factors, they do point to an interesting relationship between low IGF-1 levels and increased cardiovascular risk factors among CKD patients as compared to age-matched healthy control subjects.     

Fatigue and fitness modelled from the effects of training on performance

The purpose of this study was to compare two ways of estimating both fatigue and fitness indicators from systems model of the effects of training on performance. The model was applied to data concerning the training of a hammer thrower. The variations in performance were mathematically related to the successive amounts of training. The model equation was composed of negative (NF) and positive (PF) functions. The NF and PF were associated with the fatigue and fitness estimated in previous studies. Using another method, fatigue and fitness indicators were estimated from a combination of NF and PF. The influence of training on performance was negatively associated with fatigue (NI), and positively to fitness (PI). The changes in performance were well described by the model in the present study (r = 0.96,N = 19,P<0.001). Significant correlations were observed between NF and NI (r = 0.93,P < 0.001) on the one hand and between PF and PI (r = 0.90,P < 0.001) on the other. The absolute values and the time variations of PI and NI were closer to the change in performance than NF and PF. The NF and PF were accounted for mainly by the accumulation of amounts of training. On the other hand, NI and PI were accounted for rather by the impact of these amounts of training on performance.     

NUCLEOTYPIC EFFECT IN HOMEOTHERMS: BODY-MASS INDEPENDENT RESTING METABOLIC RATE OF PASSERINE BIRDS IS RELATED TO GENOME SIZE

The resting metabolic rate of passerines is shown to be negatively correlated with genome size when body mass is held constant (r = –0.75, P < 0.01). This finding extends previous conclusion for mammals to this bird order. The result holds when higher taxonomic levels are used instead of the species (for genera, r = –0.76, P < 0.03; for families, r = –0.991, P < 0.01) as well as when the independent contrasts derived from the resolved phylogeny are used instead of the taxa (r = –0.73, P < 0.02), with the evolutionarily older contrasts being more strongly correlated (for the contrasts older than 30 million yr, r = –0.998, P < 0.002). The concept of evolutionary characters consolidation (ECC), previously formulated for mammals, is tested with special reference to the error fraction in the total character variance. In this test, the ECC for the nucleotypic effect cannot be proven for mammals as a whole class, but it holds for the two separate orders tested, rodents and passerine birds. An upper taxonomic limit for the ECC is suggested.     

Species Richness and Patterns of Invasion in Plants, Birds, and Fishes in the United States*

We quantified broad-scale patterns of species richness and species density (mean # species/km²) for native and non-indigenous plants, birds, and fishes in the continental USA and Hawaii. We hypothesized that the species density of native and non-indigenous taxa would generally decrease in northern latitudes and higher elevations following declines in potential evapotranspiration, mean temperature, and precipitation. County data on plants (n = 3004 counties) and birds (n=3074 counties), and drainage (6 HUC) data on fishes (n = 328 drainages) showed that the densities of native and non-indigenous species were strongly positively correlated for plant species (r = 0.86, P < 0.0001), bird species (r = 0.93, P<0.0001), and fish species (r = 0.41, P<0.0001). Multiple regression models showed that the densities of native plant and bird species could be strongly predicted (adj. R² = 0.66 in both models) at county levels, but fish species densities were less predictable at drainage levels (adj. R² = 0.31, P<0.0001). Similarly, non-indigenous plant and bird species densities were strongly predictable (adj. R² = 0.84 and 0.91 respectively), but non-indigenous fish species density was less predictable (adj. R² = 0.38). County level hotspots of native and non-indigenous plants, birds, and fishes were located in low elevation areas close to the coast with high precipitation and productivity (vegetation carbon). We show that (1) native species richness can be moderately well predicted with abiotic factors; (2) human populations have tended to settle in areas rich in native species; and (3) the richness and density of non-indigenous plant, bird, and fish species can be accurately predicted from biotic and abiotic factors largely because they are positively correlated to native species densities. We conclude that while humans facilitate the initial establishment, invasions of non-indigenous species, the spread and subsequent distributions of non-indigenous species may be controlled largely by environmental factors. The U.S. Government’s right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Species richness and composition patterns of clitellate (Annelida) assemblages in the treeless spring fens: the effect of water chemistry and substrate

Spring fens are isolated treeless wetlands of a high conservation value. Their environmental conditions are strongly related to their groundwater chemistry, which controls species distribution within various groups of organisms. Clitellates, a dominant group of non-insect aquatic fauna, however, have never been studied in these habitats. It is unclear from previous studies to what extent the distribution of aquatic non-insect taxa reflects water chemistry rather than the substrate structure. We studied 34 spring fens sampled in 17 isolated sites in the Western Carpathian Mountains to determine mainly the effects of water chemistry and substrate structure on variation in species richness and composition of clitellate assemblages as examples of the non-insect fauna. A total of 34 taxa were found, with 3–15 taxa collected per sample. Species richness was negatively correlated with water mineral concentration measured as water electric conductivity (r = −0.57, P < 0.001) and positively with TOC (r = 0.60, P < 0.001). Surprisingly, the lowest number of taxa was found in calcareous fens and richness increased towards Sphagnum-fens. There was a species turnover related to changes in mineral richness and substrate characters. The main change of species composition was promoted by changes in substrate structure. The second gradient of species composition was linked with the amount of nutrients, moisture, and dominance of sphagna, and was associated with an increase of eurytopic species in fens with high nutrient availability. It was difficult to separate the effects of water chemistry and substrate on clitellate species distributions owing to the fact that variation in tufa precipitation and vegetation was driven by water chemistry changes. This study presented the first quantitative data on fen clitellate assemblages, which appear to have an unusual pattern of species richness. In contrast to plants and molluscs, calcareous fens appeared to be a harsh environment for clitellate species. Only few specialized species, mainly Trichodrilus strandi, were able to establish viable populations. The significant effect of water chemistry on clitellate distribution patterns raises questions about the direct influence of water chemistry on non-insect aquatic taxa, which have previously been considered to be mostly determined by substrate characteristics.     

Postural stability during static strain before and after a submaximal aerobic bicycle test in athletes

Control of static balance was studied in wrestlers (n = 31) in the normal state and against the background of physical fatigue, i.e., before and after a bicycle PWC ₁₇₀ test, respectively. The static balance was evaluated using a Ritm force platform (Russia) during normal basic stance (BS) and static strain (half-squatting position (HS) with the eyes open). Before physical exercise, i.e., during BS, the differences in postural control of the center of pressure (CP) between athletes and control subjects (n = 40) were nonsignificant. In the HS position, both linear and angular sway velocities of CP (LSV and ASV, respectively) were significantly lower in wrestlers (p < 0.001), and these parameters were negatively correlated with the PWC ₁₇₀ index (r = −0.454 and r = −455, p < 0.001 for LSV and ASV, respectively), which suggests that up to 20% of the sway velocity variance during static strain is dependent on the working capacity of the subjects. After the PWC ₁₇₀ test, the sway velocities of CP increased in both groups during BS (p < 0.01) and HS (p < 0.001), which testifies to the important role of muscular fatigue in the decrease in postural stability in both groups. During BS, an increase in LSV and ASV was about the same in both groups; however, during HS, an increase in the sway velocities of CP after PWC ₁₇₀ was lower in wrestlers (the intergroup differences at p = 0.037 and p = 0.008 for LSV and ASV, respectively); this parameter was negatively correlated with the recovery of the heart rate (HR) after the bicycle test (r = −0.378, p < 0.001 and r = −0.265, p < 0.05 for LSV and ASV, respectively), which suggests that rapid recovery contributes to a certain extent (about 6.5–14.2%) to the postural stability during static strain of wrestlers against the background of their physical fatigue.     

Gender differences in selected zinc metabolism parameters in patients with mild primary arterial hypertension

The relationship between selected zinc (Zn) metabolism parameters, arterial blood pressure, age, and renin-angiotensin-aldosterone system in subjects of both sexes with mild primary arterial hypertension is presented in this study. The following parameters were measured: systolic and diastolic arterial blood pressure, total and ouabain-dependent efflux rate constants of Zn from lymphocytes, serum and lymphocyte Zn concentrations, serum aldosterone, angiotensin-converting enzyme, sodium and potassium concentrations, body mass index, and plasma rennin activity. When all subjects are taken into account, no significant age-related differences were found for serum Zn. If divided into men and women, negative (r=−0.39) and positive (r=0.34) correlations are observed, respectively. Lymphocyte Zn correlated negatively with age in the entire group (r=−0.55) and also for men (r=−0.54) and women (r=−0.57). The renin-agiotensin-aldosterone system parameters correlated with those of Zn metabolism only for women: plasma rennin activity with total Zn efflux from lymphocytes (r=−0.33) and with lymphocyte Zn (r=0.71); the angiotensin-converting enzyme with total Zn efflux from lymphocytes (r=−0.35), with the oubain-dependent Zn efflux from lymphocytes (r=−0.33) and with lymphocyte Zn (r=0.57); serum aldosterone with oubain-dependent Zn efflux from lymphocytes (r=−0.44) and with lymphocyte Zn (r=0.59). For the men, the only positive correlation was that of serum Zn and aldosterone (r=0.45). In all cases (men and women), there was no negative correlation between serum Zn and angiotensin-converting enzyme. In women, the diastolic blood pressure correlated negatively with total Zn efflux from lymphocytes (r=−0.39), oubain-dependent Zn efflux from lymphocytes (r=−0.49), and serum Zn (r=−0.46); systolic blood pressure correlated negatively with lymphocyte zinc (r=−0.38). In men, the systolic blood pressure had a negative correlation with lymphocyte zinc (r=−0.32), which was also true for the entire group (r=−0.34). These results clearly show gender-related differences in Zn metabolism and indicate the need for further research to elucidate the possible causes of this phenomenon not only for Zn but for other elements as well.     

NUCLEOTYPIC EFFECT IN HOMEOTHERMS: BODY-MASS-CORRECTED BASAL METABOLIC RATE OF MAMMALS IS RELATED TO GENOME SIZE

The body-mass-corrected rate of basal metabolism in mammals is found to be negatively correlated with genome size, which is possibly linked to average cell size. The correlation, already significant at the species level (r_sp = –0.61, P < 0.0002), gradually strengthens as mean values for higher taxonomic levels (genera, families, and orders) are substituted in place of the species points (r_gen = –0.65, P < 0.0002; r_fam = –0.71, P < 0.0004; r_ord = –0.81, P < 0.008). This finding suggests that a sizeable part of the mammalian (above 25% of human) genome can be used for evolutionary adjustment of metabolic rate resulting from nucleotypic effect independently of body size. The total variance of mammalian genome-size values is found to be divided into two parts: within genera (43%) and taxonomic levels higher than order (57%), with no tangible variance being added between these taxonomic levels; whereas the body-mass-corrected rate of basal metabolism varies mainly at family (42%) and order (53%) levels. The only order for which there seems to be a necessary minimum of data for intraorder analysis (rodents) shows a not statistically significant correlation at the species level (r_sp = –0.47; P < 0.09), significant at the genus level (r_gen = –0.74; P < 0.04), and very high at the family level (r_fam = –0.98; P < 0.03). The concept of ultimate (distant) characters consolidation is proposed. In birds, with average genome sizes 40% of those of mammals, and similarly narrower ranges both of genome sizes and of body-mass-corrected metabolic rates, the correlation was not significant.     

Linking Foliar Chemistry to Forest Floor Solid and Solution Phase Organic C and N in Picea abies [L.] Karst Stands in Northern Bohemia

Dissolved organic carbon and nitrogen (DOC and DON) produced in the forest floor are important for ecosystem functions such as microbial metabolism, pedogenesis and pollutant transport. Past work has shown that both DOC and DON production are related to litterfall and standing stocks of C and N in the forest floor. This study, conducted in spring, 2003, investigated variation in forest floor water extractable DOC (WEDOC) and DON (WEDON) and forest floor C and N as a function of lignin, cellulose and N contained in live canopy foliage across eight Picea abies [L.] Karst stands in northern Bohemia. Based on Near Infrared Spectroscopy (NIR) analysis of foliar materials, lignin:N and cellulose:N content of the youngest needles (those produced in 2002) were positively and significantly related to WEDOC (R² = 0.82–0.97; P<0.01) and to forest floor C:N ratio (R = 0.72–0.78; P<0.01). Foliar N was strongly and negatively related to WEDOC and C:N ratio (R = −0.91 and 0.72; P<0.05) among our study sites. WEDON was positively correlated to foliar lignin:N (R = 0.48; P<0.05; n=40). Forest floor C pools were not positively correlated with foliar lignin and cellulose and forest floor N pools were not positively correlated with foliar N. Instead, a significant negative correlation was found between forest floor N pools and foliar cellulose (R=−0.41; P<0.05), and between forest floor C pools and foliar N (R = −0.44; P<0.05). From a remote sensing standpoint, our results are important because canopy reflectance properties are primarily influenced by the most recent foliage, and it was the chemistry of the most recently produced needles that showed a stronger relationship with forest floor WEDOC and C:N ratio suggesting forest floor production of WEDOC can be calculated regionally with remote sensing.