Nonnative pest establishment: Spatial patterns and public detection

I thank Fowler and Hobbs for their letter (2004) and their research (2003). The view that a complexity of factors impacts human population growth certainly makes sense, and they have correctly pointed out that scientifically organized efforts to deal with human problems must take account of manifold interconnected events. Although it is necessary to recognize and acknowledge the complexities inherent in cultural life and the natural world, it is equally important that a dizzying array of variables not blind us to certain scientific facts of biophysical reality. Humankind is bound by such predominant facts because the workings of the world exist independently of human wishes and beliefs. With this in mind, I thank Hopfenberg for his article (2003) in which he provided an elegant model that accounts for the salient factors governing the dynamics of global human population numbers. According to his findings, the size of the human population is determined primarily by food availability. The realization that these two points of view differ—that there is complexity and simplicity in the world we inhabit—does not necessarily mean that one is correct and the other incorrect. To the contrary, it could be that each point of view is valid based on the scope of observation. It may be somehow not quite right to agree with the entire idea of Hobbs and Fowler (2004) that “human population size is beyond human capacity to list, comprehend, and synthesize” without noticing that the same can be said regarding any observable phenomenon. Reality is likely just as complex as Hobbs and Fowler described; but it is also clear from the research of Hopfenberg (2003) and Hopfenberg and Pimentel (2001) that the dynamics of human population growth is no longer preternatural but knowable, and that the population dynamics of Homo sapiens is not essentially different from the population dynamics of other species in both the complexity and the simplicity of the governing elements. A comprehensive and objective approach to human problems and human potentiality must acknowledge that humankind is a part of the biophysical world, not apart from it. Although Hobbs and Fowler (2004) are correct to note the control human culture exercises in “value systems, economics, politics and religion” in taking account of what is real, human and environmental health could be increasingly at risk because humanity denies scientific facts over which living beings may not have control. In light of the different sets of data presented by Fowler and Hobbs (2003) and by Hopfenberg (2003), perhaps it is a misnomer for Hobbs and Fowler (2004) to uniformly describe the many, complicated ways humanity is changing the natural world as an “unprecedented success.” Are particulate and solid-waste pollution or the conversion of biomass into human mass with resulting bio-diversity loss examples of success? Perhaps the economic success of the prevailing culture is not sustainable and cannot be maintained much longer. Unbridled economic globalization, unrestricted increases in human consumption of resources, and growing absolute human population numbers are negatively affecting Earth by degrading its fitness as a habitat for humans and other species. A point in human history may have been reached when the scale and rate of growth of economic expansion, the consumption of natural resources, and the increasing human population can be seen as patently unsustainable. Understanding the causes of and limits to humanity’s impact in the world is a necessary step toward changing human production, consumption, and population trends. Regardless of how long a culture prizes growth and chooses to leave it unchecked, surely it is not too late to accept limits to growth of the human economy, human consumption, and human numbers worldwide by altering human behavior accordingly.

Effective population size (N(e)) determines the amount of genetic variation, genetic drift, and linkage disequilibrium (LD) in populations. Here, we present the first genome-wide estimates of human effective population size from LD data. Chromosome-specific effective population size was estimated for all autosomes and the X chromosome from estimated LD between SNP pairs <100 kb apart. We account for variation in recombination rate by using coalescent-based estimates of fine-scale recombination rate from one sample and correlating these with LD in an independent sample. Phase I of the HapMap project produced between 18 and 22 million SNP pairs in samples from four populations: Yoruba from Ibadan (YRI), Nigeria; Japanese from Tokyo (JPT); Han Chinese from Beijing (HCB); and residents from Utah with ancestry from northern and western Europe (CEU). For CEU, JPT, and HCB, the estimate of effective population size, adjusted for SNP ascertainment bias, was approximately 3100, whereas the estimate for the YRI was approximately 7500, consistent with the out-of-Africa theory of ancestral human population expansion and concurrent bottlenecks. We show that the decay in LD over distance between SNPs is consistent with recent population growth. The estimates of N(e) are lower than previously published estimates based on heterozygosity, possibly because they represent one or more bottlenecks in human population size that occurred approximately 10,000 to 200,000 years ago.

Aim To investigate how the magnitude of conservation conflicts arising from positive relationships between human population size and species richness is altered during a period of marked human population growth (2% year − 1 ). Location South Africa. Methods Anuran and avian species richness were calculated from atlas distribution maps, and human population was measured in 1996 and 2001, all at a quarter-degree resolution. We investigated the relationships between human population size in, and its change during, these two periods and environmental energy availability. We then investigated the nature of relationships between species richness and human population size in both time periods, and its change during them; these analyses were conducted both with and without taking environmental energy availability into account. Finally, we investigated the nature of the relationships between human population size, and its change, and the proportion of protected land. Analyses were conducted both without and with taking spatial autocorrelation into account; the latter was achieved using mixed models that fitted a spatial covariance structure to the data. Results Change in human population size between 1996 and 2001 exhibited marked spatial variation, with both large increases and decreases, but was poorly correlated with environmental energy availability. The nature of the relationship between human population size and environmental energy availability did not, however, exhibit statistically significant differences regardless of whether the former was measured in 1996 or 2001. Similarly, relationships between species richness and human population size did not exhibit significant differences between the two periods. The strengths of the species‐ human relationships were markedly reduced when energy availability was taken into account. Change in human population size was poorly correlated with species richness. The proportion of protected land was negatively, albeit rather weakly, correlated with human population size in 1996 and 2001, and with its change between these two periods. Main conclusions Positive species‐human relationships arise largely, but not entirely, because both species richness and human population size exhibit similar responses to environmental energy availability. During a period of rapid human population growth, and marked changes in the spatial variation in human population size, positive correlations remained between human population size and both anuran and avian species richness. The slope of these correlations did not, however, alter, and the most species-rich areas are not those with the largest increases in human population. Despite marked population growth, the magnitude of conservation conflicts arising from positive species‐human relationships thus appears to have remained largely unchanged.

ABSTRACTAim To investigate how the magnitude of conservation conflicts arising from positive relationships between human population size and species richness is altered during a period of marked human population growth (2% year−1).Location South Africa.Methods Anuran and avian species richness were calculated from atlas distribution maps, and human population was measured in 1996 and 2001, all at a quarter‐degree resolution. We investigated the relationships between human population size in, and its change during, these two periods and environmental energy availability. We then investigated the nature of relationships between species richness and human population size in both time periods, and its change during them; these analyses were conducted both with and without taking environmental energy availability into account. Finally, we investigated the nature of the relationships between human population size, and its change, and the proportion of protected land. Analyses were conducted both without and with taking spatial autocorrelation into account; the latter was achieved using mixed models that fitted a spatial covariance structure to the data.Results Change in human population size between 1996 and 2001 exhibited marked spatial variation, with both large increases and decreases, but was poorly correlated with environmental energy availability. The nature of the relationship between human population size and environmental energy availability did not, however, exhibit statistically significant differences regardless of whether the former was measured in 1996 or 2001. Similarly, relationships between species richness and human population size did not exhibit significant differences between the two periods. The strengths of the species–human relationships were markedly reduced when energy availability was taken into account. Change in human population size was poorly correlated with species richness. The proportion of protected land was negatively, albeit rather weakly, correlated with human population size in 1996 and 2001, and with its change between these two periods.Main conclusions Positive species–human relationships arise largely, but not entirely, because both species richness and human population size exhibit similar responses to environmental energy availability. During a period of rapid human population growth, and marked changes in the spatial variation in human population size, positive correlations remained between human population size and both anuran and avian species richness. The slope of these correlations did not, however, alter, and the most species‐rich areas are not those with the largest increases in human population. Despite marked population growth, the magnitude of conservation conflicts arising from positive species–human relationships thus appears to have remained largely unchanged.

The effects of climate and population on human land use patterns in Europe from 22ka to 9ka ago

Spatial distribution patterns of the dominant canopy dipterocarp species in a seasonal dry evergreen forest in western Thailand

We would like to thank Bob Weinhold (2004) for his informative article documenting the issues facing humans in regard to infectious disease and the growing concern within the medical community that traditional thinking, approaches, and methods may well be inadequate to face the challenges ahead. We would also like to thank Steven Salmony (2004) for his thoughtful letter regarding Weinhold’s (2004) article, in which he presents another extremely important issue: that of human population growth and its interconnection with food resources. Both of these articles report the results of good science, and both describe well some of the critical issues facing humans at this time. We would like to present another viewpoint that we believe is both more helpful and more accurate for describing the problems we face and for setting research and decision-making goals that will involve the health of all systems. Our approach (Fowler and Hobbs 2002, 2003) stems from systemic thinking as a paradigm that is emergent from modern systems theory, cybernetics, and information theory from their beginnings in the late 1940s. Basically, this way of thinking posits that all things are intricately interconnected in very complex ways, so that any action (or inaction, for that matter) will always result in a variety of consequences. Some of these we can predict and some we cannot; some will be evaluated as positive and some will be evaluated as negative in human value systems. Examples of these systemic reactions can be given for any field of inquiry (e.g., environmental, social, political, religious, personal) and at any level of organization (e.g., individual, species, ecosystem, biosphere); what we find is that there is never a single cause or a single outcome. It is always more complex than that. As humans, we have been able to ignore this complexity until very recently because simple cause-and-effect models were accurate enough to help us deal with the problems we faced. However, as we have become more sophisticated with our technologies, we are experiencing unprecedented success at altering our world. The resulting changes are so profound that simple models no longer adequately describe the problems or define goals and guidelines to solve these problems. Certainly, as Hopfenberg (2003) so clearly pointed out, humans are biological organisms, and food availability is one of the factors that contribute to the wealth of factors that determine population size. It is, however, also true that the number of other factors that influence human population size is beyond human capacity to list, comprehend, and synthesize. We cannot measure them all nor can we accurately weigh the relative importance of each factor’s influence on the actual number of humans (e.g., disease, parasites, social upheaval, religious viewpoints, economics). Each such factor is, in turn, influenced by other factors. For example, weather patterns influence the amount of food available. Ocean currents influence weather patterns; the orbiting of the earth and moon influence ocean currents; the orbits of other planets and the gravitational forces of the sun and other celestial bodies influence the orbits of the earth and moon; and so on. In each case, there are multitudes of other factors involved. The amount of food available is dependent on, or influenced by, microbes, other consumers, and predators and prey at all levels. A huge variety of physical forces is also at play in influencing primary and other levels of production, including volcanoes, hurricanes, floods, forest fires, and various human influences such as the use of pesticides and fertilizers and increased carbon dioxide production. Human population numbers are also dependent on an enormous number of factors beyond food, including disease and all the other factors that were listed by Weinhold (2004). Had we been unable to curtail the effects of smallpox, for example, the human population would probably be smaller than it is today, as is the case for so many wildlife species whose populations are regulated, in part, by the effects of disease. However, when considering human population numbers, human value systems, economics, politics, and religion, all factors over which we have some limited measure of control, must also be taken into account. We believe that any approach to dealing with human problems must take into account all of this complexity or it will lead to more problems. A systemic approach, such as we propose in our work (Fowler and Hobbs 2002, 2003), takes into account all of this complexity and also gives empirical guidelines for how to deal with the problems. It not only allows us to deal with how much food can be sustainably extracted from the various resource systems to feed ourselves but addresses the deeper and, we believe, more important question: how many of us should there be to feed?

PDF HTML阅读 XML下载 导出引用 引用提醒 秦岭林区锐齿栎次生林种群空间分布格局 DOI: 10.5846/stxb201406291343 作者: 作者单位: 西北农林科技大学 林学院,西北农林科技大学 林学院,西北农林科技大学 林学院,西北农林科技大学 林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业专项项目(201204502) Spatial pattern of secondary Quercus aliena var. acuteserrata forests in the Qinling Mountains Author: Affiliation: College of Forestry,Northwest Agriculture Forest University,Yangling,College of Forestry,Northwest Agriculture Forest University,Yangling,College of Forestry,Northwest Agriculture Forest University,Yangling,College of Forestry,Northwest Agriculture Forest University,Yangling Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以秦岭林区阳坡、阴坡2个典型地段上的锐齿栎次生林为研究对象,运用点格局分析方法O-ring函数分析了不同坡向、不同发育阶段种群空间分布格局及不同坡向锐齿栎种群的种内与种间空间关联性,探讨锐齿栎空间格局形成和种群维持机制。结果表明:阴坡锐齿栎种群聚集程度高于阳坡;两种坡向种群各发育阶段空间分布格局相似,从幼树到大树均呈现出聚集到随机甚至均匀分布的规律;不同坡向种群各发育阶段间关联性不同,阳坡各发育阶段间呈一定的正相关,而阴坡呈一定的负相关;阳坡中,山杨与锐齿栎种群分布呈一定正相关,灯台树、鹅耳枥与其呈一定负相关,在阴坡,山杨、漆树与锐齿栎呈一定正相关,灯台树、青榨槭、鹅耳枥与其呈一定负相关。结果表明:目前,阳坡锐齿栎种群结构较好,种内、种间竞争不激烈,而阴坡种群不仅受种间竞争的影响,同样受到种内竞争的制约,最终导致其林分结构较差,更新不良,从长远上看,适当疏伐可以增加林内透光性,有益于促进种群的更新与稳定。 Abstract:Study of the spatial patterns of populations can provide many important clues about underlying processes forming these patterns. The population of secondary growth Quercus aliena var. acuteserrata is a representative forest type in the Qinling Mountains. This study was intended to investigate the spatial patterns of secondary Quercus aliena var. acuteserrata forests and to provide a basis for managing natural forests. Two sample plots were established, on a sunny slope and a shady slope, to analyze and compare spatial patterns of Quercus aliena var. acuteserrata population. The pair correlation function and univariate statistics of point patterns were used to analyze the spatial distribution of different development stages and habitats, while bivariate statistics was used to analyze spatial associations of different stages and of different populations on each plot. The change in population spatial pattern and association among different development stages and different populations was compared to explore inherent mechanisms forming the spatial patterns. The results show that spatial distribution patterns and the age structure of the Quercus aliena var. acuteserrata population were different for sunny and shady slopes. The degree of spatial distribution aggregated on the shady slope was higher than that on the sunny slope. The age structure appeared a reverse ‘J’ type on the sunny slope (growing type), while the population renewal was poor on the shady slope (declining type). Initially, different developmental stages showed similar distribution patterns on both slopes, but these became random when young trees matured. Some differences appeared in the relevance of each development stage on each slope. Positive association was observed among developmental stages on the sunny slope, while negative association was observed among developmental stages on the shady slope. For example, on the sunny slope, the distribution patterns of Quercus aliena var. acuteserrata population were positively associated with Populus davidiana, but negatively associated with Bothrocaryum controversum and Carpinus turczaninowii. On the shady slope, the distribution patterns of Quercus aliena var. acuteserrata population were positively associated with Populus davidiana and Toxicodendron vernicifluum, but negatively associated with Bothrocaryum controversum, Acer davidii and Carpinusturc zaninowii. In summary, the distribution patterns of Quercus aliena var. acuteserrata population were basically reasonable on the sunny slope; intraspecific and interspecific competition were not fierce. The distribution patterns within the Quercus aliena var. acuteserrata population were not only influenced by interspecific competition, but were also restricted by intraspecific competition on the shady slope, suggesting that proper thinning could increase light transmittance, thereby improving the regeneration and stability of such Quercus aliena var. acuteserrata population. 参考文献 相似文献 引证文献

Anuran species richness, complementarity and conservation conflicts in Brazilian Cerrado

Editor's evaluation: Plasmodium falciparum adapts its investment into replication versus transmission according to the host environment

Several extrinsic factors (area, native species diversity, human population size and latitude) significantly influence the non-native species richness of plants, over several orders of magnitude. Using several data sets, I examine the role of these factors in non-native species richness of several animal groups: birds, mammals and herptiles (amphibians, reptiles). I also examine if non-native species richness is correlated among these groups. I find, in agreement with Sax [2001, Journal of Biogeography 28: 139–150], that latitude is inversely correlated with non-native species richness of many groups. Once latitude is accounted for, area, human population size and native plant species richness are shown to be important extrinsic factors influencing non-native animal species. Of these extrinsic factors, human population size and native plant species richness are the best predictors of non-native animal species richness. Area, human population size and native plant species richness are highly intercorrelated, along with non-native species richness of all taxa. Indeed a factor analysis shows that a single multivariate axis explains over half of the variation for all variables among the groups. One reason for this covariation is that humans tend to most densely occupy the most productive and diverse habitats where native plant species richness is very high. It is thus difficult to disentangle the effects of human population size and native species richness on non-native species richness. However, it seems likely that these two factors may combine to increase non-native species richness in a synergistic way: high native species richness reflects greater habitat variety available for non-native species, and dense human populations (that preferentially occupy areas rich in native species) increase non-native species importation and disturbance of local habitats.

There is a significant positive association between exotic plant species richness of an area and the human population size of that area. This association is notable not only for its high correlation (r2 = 0.69) but also because it spans five orders of magnitude for human population size. The correlation is apparently caused by the introduction of increasing numbers of exotic species as human population size grows. As population grows, so does exotic propagule importation and habitat disturbance. The regression is clearly asymptotic, indicating that per capita rates of exotic species introductions decline as human population continues to increase. A main implication for exotic species control is that efforts to limit exotic species will be most effective and least costly in areas (at many scales) where human population size is still relatively small. Another implication is that because human population size will continue to increase in many areas, educating the general public about harmful exotic ...

ABSTRACTAim To quantify the relationship between the description dates of anuran species in the Brazilian Cerrado and some macroecological traits, and to verify the spatial patterns of average description dates and their correlation with human occupation and biodiversity knowledge.Location Brazilian Cerrado (South America).Methods The average date of description of 131 species of anurans found in 181 cells overlaying the Brazilian Cerrado was recorded. Description date was regressed across species on body size and geographical range size. Phylogenetic effects that could bias the significance tests of the multiple regression model of description dates on macroecological traits were taken into account using a phylogenetic subtraction method in which families and genera were classificatory factors in a nested two‐way analysis of variance (anova) model. We also conducted a spatial analysis of the average description date that was estimated for each cell. This cell‐based metric was regressed on human population size, the year of foundation of the municipalities and the number of inventories undertaken in each cell. The influence of spatial autocorrelation patterns was taken into account by using the geographically effective number of degrees of freedom.Results The number of new species being discovered in the Brazilian Cerrado has been increasing, especially over the last 50 years. Cross‐species analyses indicated that description dates were negatively correlated with body size and geographical range size, taking phylogenetic effects into account. Even after controlling for the spatial structures in all variables, average description date was positively correlated with human population in geographical space, but because of multicolinearity structure in the data, it was not possible to quantify the independent influence of human population and number of inventories on description date.Conclusions As found in previous papers, large‐bodied and widely distributed species are likely to be described first. Species yet to be discovered are probably small‐bodied and with narrow distributions, more restricted to the Cerrado biome. Also, the explicit spatial approach showed that the average description date is spatially correlated with total human population and biodiversity knowledge in the Cerrado region. Our findings suggest that incorporating human population density into the reserve design algorithms, which has usually been done to avoid or minimize conservation conflicts, may also produce good results because this will preserve many places where most of the non‐described species will probably be found in the future.

New estimations of habitable land area and human population size at the Last Glacial Maximum

SUMMARY Fundamental to environmental conservation, the spatial location of biodiversity, people and protected areas has been studied for the species richness of various taxa, including plants, invertebrates and birds. However, few avian studies have analysed these three-way interactions for total versus breeding, and for threatened, human-avoiding and human–adapted species. Correlations between bird species richness, human population size and protected areas were studied across Italy's regions, controlling for variations in area, latitude, main land cover and spatial autocorrelation. Whilst total bird species richness increases with increasing human population size, breeding species richness does not vary with human population size. The number of globally threatened bird species is positively correlated with human population size, but this correlation is not significant when controlling for overall region bird species richness. There is no evidence that the increase in total bird species richness with human population size is owing to species typically found in urban habitats, and the proportion of human-avoiding species increases with human population size. For all groups of species, there is a negative correlation of the number of species with the proportion of protected area, indicating that the conservation of Italy's avifauna should be addressed over the entire landscape, and not just in protected areas.