Existing general definitions of beta diversity often produce a beta with a hidden dependence on a... more Existing general definitions of beta diversity often produce a beta with a hidden dependence on alpha. Such a beta cannot be used to compare regions that differ in alpha diversity. To avoid misinterpretation, existing definitions of alpha and beta must be replaced by a definition that partitions diversity into independent alpha and beta components. Such a unique definition is derived here. When these new alpha and beta components are transformed into their numbers equivalents (effective numbers of elements), Whittaker's multiplicative law (alpha x beta = gamma) is necessarily true for all indices. The new beta gives the effective number of distinct communities. The most popular similarity and overlap measures of ecology (Jaccard, Sorensen, Horn, and Morisita-Horn indices) are monotonic transformations of the new beta diversity. Shannon measures follow deductively from this formalism and do not need to be borrowed from information theory; they are shown to be the only standard diversity measures which can be decomposed into meaningful independent alpha and beta components when community weights are unequal.
We investigated effects of plant density on floral phenology and potential mating in artificial p... more We investigated effects of plant density on floral phenology and potential mating in artificial populations of the outcrossing ornamental Nicotiana alata planted at three densities. Path analysis revealed that increasing plant density yielded significantly earlier peak flowering dates, significantly earlier last flowering dates, and significantly lower plant biomass. Direct effects of density on final flower number were not significant. Variation among replicate plots for first date of flowering was larger than variation among densities, indicating that factors other than density influence floral initiation. We did not record actual mating, but determined from phenological data the number and identity of potential mates. Increased density had several effects on potential mating patterns and on potential Ne, effective population number. At high density, fewer focal plants flowered for shorter durations. This led to less overlap in flowering time among plants, decreasing the number of potential parental combinations possible among the progeny. Two outcomes of high density, the lower total number of plants flowering and the lower number of plants flowering at most census dates, tended to reduce potential Ne. In contrast, it was low density, where variance in flower number was greatest, that was most likely to yield the greatest reduction in Ne due to variance in progeny number. At high density the potential for assortative mating among tall plants was much greater and occurred later than among large plants at low density. Much of the potential high density assortative mating occurred late in the phenology of individual plants, when there was likely to be lower fruit set. We discuss how ecological agents that alter flowering phenology can potentially alter the genetics of populations, the level and timing of assortative mating and, if genetic variation for response to such ecological agents exists, the potential selection regime.
The size hierarchy and mineral concentrations of adult plants in flower and their seed crop have ... more The size hierarchy and mineral concentrations of adult plants in flower and their seed crop have been investigated in three populations of Rhinanthus angustifolius under a grassland management regime consisting of haying without fertilization. The effect of this type of management on the nutrient budgets of soil or Rhinanthus plants was shown to be small initially, i.e. up to the twelfth year of changed management. Although the mean biomass of plants significantly diminished by 30% in this period, their nutrient concentration was not strongly affected. Small plants consistently had lower concentrations of N and Na than large plants. Prolongation of this management regime beyond twelve years let to a general reduction in the phosphorus concentration of the plants. An observed increase in the concentrations of K, Mn, and Cu, especially in small plants, is tentatively ascribed to an imbalance in mineral nutrition.
Pollen dispersal is a critical process defining connectivity among plant populations. In the cont... more Pollen dispersal is a critical process defining connectivity among plant populations. In the context of genetically modified (GM) crops in conventional agricultural systems, strategies based on spatial separation are promoted to reduce functional connectivity between GM and non-GM crop fields. Field experiments as well as simulation studies have stressed the dependence of maize gene flow on distances between source and receptor fields and on their spatial configuration. However, the influence of whole landscape patterns is still poorly understood. Spatially explicit models, such as MAPOD-maize, are thus useful tools to address this question. In this paper we developed a methodological approach to investigate the sensitivity of cross-pollination rates among GM and non-GM maize in a landscape simulated with MAPOD-maize. The influence of landscape pattern on model output was studied at the landscape and field scales, including interactions with other model inputs such as cultivar characteristics and wind conditions. At the landscape scale, maize configuration (proportion of and spatial arrangement in a given field pattern) was shown to be an important factor influencing cross-pollination rate between GM and non-GM maize whereas the effect of the field pattern itself was lower. At the field scale, distance to the nearest GM maize field was confirmed as a predominant factor explaining cross-pollination rate. The metrics describing the pattern of GM maize in the area surrounding selected non-GM maize fields appeared as pertinent complementary variables. In contrast, field geometry and field pattern resulted in little additional information at this scale.
Inequalities in size in populations have potentially important effects on fitness but have rarely... more Inequalities in size in populations have potentially important effects on fitness but have rarely been examined in natural populations. I measured size (number of culms) and fecundity (number of spikelets) in five populations of the grass Danthonia spicata from 1981 to 1985. The populations were in sites in a Pinus-Quercus-Populus forest in northern lower Michigan, USA comprising a secondary succession sequence. The sites had been burned in 1980, 1954, 1948, 1936, and 1911, respectively. Mean sizes and fecundities and the amount of hierarchy in size and fecundity, measured by the Gini coefficient, were compared between the YOUNG population, 1980 burn site, and the OLD populations, 1954, 1948, 1936, and 1911 burn sites. I found large differences in mean size and fecundity between the YOUNG and OLD populations with much larger individuals in the YOUNG population. No differences in size hierarchies were found in either the first year of measurement or after five years. The fecundity hierarchies showed no significant difference among the populations in the first year but after five years the YOUNG population showed a significant decrease in amount of inequality. The longterm patterns of size and fecundity hierarchies differed because fecundity was a cumulative trait while size was not. Size inequalities may not always be a good measure of fecundity inequalities. Short-term measures of inequality in perennials may not be a good indicator of long-term values. In contrast to greenhouse studies, habitat light levels did not affect size hierarchies although they did affect fecundity hierarchies.
IEEE Transactions on Geoscience and Remote Sensing, 2011
Opium is a narcotic obtained from opium poppy and is the raw material of heroin for the illegal d... more Opium is a narcotic obtained from opium poppy and is the raw material of heroin for the illegal drug trade. Monitoring the illegal concentrated cultivation of opium poppy in major regions is critical for the understanding by governments and international communities of the scale of illegal drug trade. This paper investigates whether opium poppy can be discriminated from its coexisting plants using analytical-spectral-device field spectrometer data in the visible to short-wave infrared spectral range. Canopy spectral measurements were conducted during three different growth periods of opium poppy. A synthetic method with three analysis levels was applied to discriminate opium poppy from other species and to select optimal bands for opium poppy discrimination. First, the Mann-Whitney U-test method was used to test the spectral reflectance difference between opium poppy and coexisting crops at each wavelength. Then, the Jeffries-Matusita distance and band correlation analysis were conducted to select the optimal wavebands for discriminating opium poppy using the significant wavebands from the test results. Finally, classification and regression tree analysis was employed to validate the classification accuracy based on the selected optimal wavebands. The results indicated that the spectral reflectance of opium poppy was significantly different from that of coexisting crops in many surveyed wavebands, and opium poppy could be discriminated using a field survey spectrum at canopy level. The best time for discriminating opium poppy from coexisting crops was around flowering time. This paper provided the prerequisite for monitoring opium poppy using satellite remote sensing data in some regions of concern.
Purpose – The purpose of this paper is to offer a counter-intuitive conceptual framework to the s... more Purpose – The purpose of this paper is to offer a counter-intuitive conceptual framework to the study and the management of workaholism. The paper proposes that the phenomenon can be constructive, generating welcoming outcomes for individuals, organizations and societies. Design/methodology/approach – A set of propositions about workaholism and its management under various contexts is presented and discussed. Findings – Workaholics
A greenhouse experiment was conducted to investigate the impact of sanitized (Autothermal Thermop... more A greenhouse experiment was conducted to investigate the impact of sanitized (Autothermal Thermophilic Aerobic Digested, ATAD) and non-sanitized (Anaerobic Mesophile Digested) sewage sludge on the activity and functional diversity of soil microbial community and the physiology of pepper plants (Capsicum annuum L. cv. Piquillo). ATAD and anaerobic mesophile sludges were applied to soils at three rates (3, 6 and 12 g (dry matter) per pot) and unamended soil was included as a control. Results showed that ATAD and mesophile sludge application increased the growth and yield of plants, and accelerated their phenological development as the sludge rate increased. The increased growth was a result of the enhanced capacity of plants to produce more leaves and the greater photosynthetic activity per unit leaf area. Besides nutrient supply, the increased soil microbial activity and biomass in amended soils might have indirectly contributed to the enhanced growth and yield of plants. Sludge application decreased soil functional diversity and caused a shift in the community-level physiological profile. Although ATAD and anaerobic mesophile sludges exerted similar effects on plant development, the type of sludge influenced the activity and functional diversity of soil microbial community. Results are discussed in relation to the environmental benefits associated with the ATAD process for sludge treatment.
Specialty crops (fruits, vegetables, grapes and wine, ornamentals—nursery and floriculture—tree n... more Specialty crops (fruits, vegetables, grapes and wine, ornamentals—nursery and floriculture—tree nuts, berries, and dried fruits) comprise a substantial—and growing—portion of agribusiness. Still, the industry is facing a number of severe problems that must be resolved to sustain it and promote its continued growth. This paper is intended to provide growers and distribution managers insights into the variety of decision support possible and benchmarks for improvements they can help to achieve and to provide academic researchers with insights into industry operations and a vision of research needs.
Existing general definitions of beta diversity often produce a beta with a hidden dependence on a... more Existing general definitions of beta diversity often produce a beta with a hidden dependence on alpha. Such a beta cannot be used to compare regions that differ in alpha diversity. To avoid misinterpretation, existing definitions of alpha and beta must be replaced by a definition that partitions diversity into independent alpha and beta components. Such a unique definition is derived here. When these new alpha and beta components are transformed into their numbers equivalents (effective numbers of elements), Whittaker's multiplicative law (alpha x beta = gamma) is necessarily true for all indices. The new beta gives the effective number of distinct communities. The most popular similarity and overlap measures of ecology (Jaccard, Sorensen, Horn, and Morisita-Horn indices) are monotonic transformations of the new beta diversity. Shannon measures follow deductively from this formalism and do not need to be borrowed from information theory; they are shown to be the only standard diversity measures which can be decomposed into meaningful independent alpha and beta components when community weights are unequal.
We investigated effects of plant density on floral phenology and potential mating in artificial p... more We investigated effects of plant density on floral phenology and potential mating in artificial populations of the outcrossing ornamental Nicotiana alata planted at three densities. Path analysis revealed that increasing plant density yielded significantly earlier peak flowering dates, significantly earlier last flowering dates, and significantly lower plant biomass. Direct effects of density on final flower number were not significant. Variation among replicate plots for first date of flowering was larger than variation among densities, indicating that factors other than density influence floral initiation. We did not record actual mating, but determined from phenological data the number and identity of potential mates. Increased density had several effects on potential mating patterns and on potential Ne, effective population number. At high density, fewer focal plants flowered for shorter durations. This led to less overlap in flowering time among plants, decreasing the number of potential parental combinations possible among the progeny. Two outcomes of high density, the lower total number of plants flowering and the lower number of plants flowering at most census dates, tended to reduce potential Ne. In contrast, it was low density, where variance in flower number was greatest, that was most likely to yield the greatest reduction in Ne due to variance in progeny number. At high density the potential for assortative mating among tall plants was much greater and occurred later than among large plants at low density. Much of the potential high density assortative mating occurred late in the phenology of individual plants, when there was likely to be lower fruit set. We discuss how ecological agents that alter flowering phenology can potentially alter the genetics of populations, the level and timing of assortative mating and, if genetic variation for response to such ecological agents exists, the potential selection regime.
The size hierarchy and mineral concentrations of adult plants in flower and their seed crop have ... more The size hierarchy and mineral concentrations of adult plants in flower and their seed crop have been investigated in three populations of Rhinanthus angustifolius under a grassland management regime consisting of haying without fertilization. The effect of this type of management on the nutrient budgets of soil or Rhinanthus plants was shown to be small initially, i.e. up to the twelfth year of changed management. Although the mean biomass of plants significantly diminished by 30% in this period, their nutrient concentration was not strongly affected. Small plants consistently had lower concentrations of N and Na than large plants. Prolongation of this management regime beyond twelve years let to a general reduction in the phosphorus concentration of the plants. An observed increase in the concentrations of K, Mn, and Cu, especially in small plants, is tentatively ascribed to an imbalance in mineral nutrition.
Pollen dispersal is a critical process defining connectivity among plant populations. In the cont... more Pollen dispersal is a critical process defining connectivity among plant populations. In the context of genetically modified (GM) crops in conventional agricultural systems, strategies based on spatial separation are promoted to reduce functional connectivity between GM and non-GM crop fields. Field experiments as well as simulation studies have stressed the dependence of maize gene flow on distances between source and receptor fields and on their spatial configuration. However, the influence of whole landscape patterns is still poorly understood. Spatially explicit models, such as MAPOD-maize, are thus useful tools to address this question. In this paper we developed a methodological approach to investigate the sensitivity of cross-pollination rates among GM and non-GM maize in a landscape simulated with MAPOD-maize. The influence of landscape pattern on model output was studied at the landscape and field scales, including interactions with other model inputs such as cultivar characteristics and wind conditions. At the landscape scale, maize configuration (proportion of and spatial arrangement in a given field pattern) was shown to be an important factor influencing cross-pollination rate between GM and non-GM maize whereas the effect of the field pattern itself was lower. At the field scale, distance to the nearest GM maize field was confirmed as a predominant factor explaining cross-pollination rate. The metrics describing the pattern of GM maize in the area surrounding selected non-GM maize fields appeared as pertinent complementary variables. In contrast, field geometry and field pattern resulted in little additional information at this scale.
Inequalities in size in populations have potentially important effects on fitness but have rarely... more Inequalities in size in populations have potentially important effects on fitness but have rarely been examined in natural populations. I measured size (number of culms) and fecundity (number of spikelets) in five populations of the grass Danthonia spicata from 1981 to 1985. The populations were in sites in a Pinus-Quercus-Populus forest in northern lower Michigan, USA comprising a secondary succession sequence. The sites had been burned in 1980, 1954, 1948, 1936, and 1911, respectively. Mean sizes and fecundities and the amount of hierarchy in size and fecundity, measured by the Gini coefficient, were compared between the YOUNG population, 1980 burn site, and the OLD populations, 1954, 1948, 1936, and 1911 burn sites. I found large differences in mean size and fecundity between the YOUNG and OLD populations with much larger individuals in the YOUNG population. No differences in size hierarchies were found in either the first year of measurement or after five years. The fecundity hierarchies showed no significant difference among the populations in the first year but after five years the YOUNG population showed a significant decrease in amount of inequality. The longterm patterns of size and fecundity hierarchies differed because fecundity was a cumulative trait while size was not. Size inequalities may not always be a good measure of fecundity inequalities. Short-term measures of inequality in perennials may not be a good indicator of long-term values. In contrast to greenhouse studies, habitat light levels did not affect size hierarchies although they did affect fecundity hierarchies.
IEEE Transactions on Geoscience and Remote Sensing, 2011
Opium is a narcotic obtained from opium poppy and is the raw material of heroin for the illegal d... more Opium is a narcotic obtained from opium poppy and is the raw material of heroin for the illegal drug trade. Monitoring the illegal concentrated cultivation of opium poppy in major regions is critical for the understanding by governments and international communities of the scale of illegal drug trade. This paper investigates whether opium poppy can be discriminated from its coexisting plants using analytical-spectral-device field spectrometer data in the visible to short-wave infrared spectral range. Canopy spectral measurements were conducted during three different growth periods of opium poppy. A synthetic method with three analysis levels was applied to discriminate opium poppy from other species and to select optimal bands for opium poppy discrimination. First, the Mann-Whitney U-test method was used to test the spectral reflectance difference between opium poppy and coexisting crops at each wavelength. Then, the Jeffries-Matusita distance and band correlation analysis were conducted to select the optimal wavebands for discriminating opium poppy using the significant wavebands from the test results. Finally, classification and regression tree analysis was employed to validate the classification accuracy based on the selected optimal wavebands. The results indicated that the spectral reflectance of opium poppy was significantly different from that of coexisting crops in many surveyed wavebands, and opium poppy could be discriminated using a field survey spectrum at canopy level. The best time for discriminating opium poppy from coexisting crops was around flowering time. This paper provided the prerequisite for monitoring opium poppy using satellite remote sensing data in some regions of concern.
Purpose – The purpose of this paper is to offer a counter-intuitive conceptual framework to the s... more Purpose – The purpose of this paper is to offer a counter-intuitive conceptual framework to the study and the management of workaholism. The paper proposes that the phenomenon can be constructive, generating welcoming outcomes for individuals, organizations and societies. Design/methodology/approach – A set of propositions about workaholism and its management under various contexts is presented and discussed. Findings – Workaholics
A greenhouse experiment was conducted to investigate the impact of sanitized (Autothermal Thermop... more A greenhouse experiment was conducted to investigate the impact of sanitized (Autothermal Thermophilic Aerobic Digested, ATAD) and non-sanitized (Anaerobic Mesophile Digested) sewage sludge on the activity and functional diversity of soil microbial community and the physiology of pepper plants (Capsicum annuum L. cv. Piquillo). ATAD and anaerobic mesophile sludges were applied to soils at three rates (3, 6 and 12 g (dry matter) per pot) and unamended soil was included as a control. Results showed that ATAD and mesophile sludge application increased the growth and yield of plants, and accelerated their phenological development as the sludge rate increased. The increased growth was a result of the enhanced capacity of plants to produce more leaves and the greater photosynthetic activity per unit leaf area. Besides nutrient supply, the increased soil microbial activity and biomass in amended soils might have indirectly contributed to the enhanced growth and yield of plants. Sludge application decreased soil functional diversity and caused a shift in the community-level physiological profile. Although ATAD and anaerobic mesophile sludges exerted similar effects on plant development, the type of sludge influenced the activity and functional diversity of soil microbial community. Results are discussed in relation to the environmental benefits associated with the ATAD process for sludge treatment.
Specialty crops (fruits, vegetables, grapes and wine, ornamentals—nursery and floriculture—tree n... more Specialty crops (fruits, vegetables, grapes and wine, ornamentals—nursery and floriculture—tree nuts, berries, and dried fruits) comprise a substantial—and growing—portion of agribusiness. Still, the industry is facing a number of severe problems that must be resolved to sustain it and promote its continued growth. This paper is intended to provide growers and distribution managers insights into the variety of decision support possible and benchmarks for improvements they can help to achieve and to provide academic researchers with insights into industry operations and a vision of research needs.
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