Relationship of Effective to Census Size in Fluctuating Populations

Abstract: The effective size of a population (    N _e   ) rather than the census size (    N ) determines its rate of genetic drift. Knowing the ratio of effective to census size, N _e  /   N , is useful for estimating the effective size of a population from census data and for examining how different ecological factors influence effective size. Two different multigenerational ratios have been used in the literature based on either the arithmetic mean or the harmonic mean in the denominator. We clarify the interpretation and meaning of these ratios. The arithmetic mean N _e  /   N ratio compares the total number of real individuals to the long-term effective size of the population. The harmonic mean N _e  /   N ratio summarizes variation in the N _e  /   N ratio for each generation. In addition, we show that the ratio of the harmonic mean population size to the arithmetic mean population size provides a useful measure of how much fluctuation in size reduced the effective size of a population. We discuss applications of these ratios and emphasize how to use the harmonic mean N _e  /   N ratio to estimate the effective size of a population over a period of time for which census counts have been collected.     

Rapid enzyme immunoassays for the detection of carbaryl and methoprene in grains

In order for grain handlers and traders to reliably estimate residues of grain protectants in the field, antibody-based rapid tests were developed for carbaryl (1-naphthyl methylcarbamate) and methoprene [isopropyl (E,E)-(RS)-11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate]. To complement the rapid analysis, a simple and rapid extraction technique was developed. In these tests, a pesticide-containing methanol extract of the grain sample and an enzyme-labeled component are added to precoated strips. After a brief incubation, the strips are washed and a substrate/chromogen for the enzyme is added. The color developed is stopped by acidification and the results are read either by eye or in a portable field photometer. The overall test time is under 20 minutes. For carbaryl, the test had a limit of detection of 4.5 ppb (1.1 ppm in grain), while the methoprene test had a limit of detection of 4 ppb (1 ppm in grain) based on the lower datum point, which is 15% inhibition, in the standard curves. Both assays can be used as a screening test for carbaryl and methoprene in animal feed grains.     

Estimation of selected physicochemical properties for methylated naphthalene compounds

Liquid aqueous solubility (S(w,L)), octanol/water partition coefficients (K(ow)), liquid vapor pressure (P(v,L)), and Henry's law constants (H(c)) were estimated for 20 methylated naphthalenes ranging from monomethyl to tetramethylnaphthalenes. Chromatographic methods were used for the estimation. Chromatographic retention measurements were conducted for 11 reference compounds and regressions were fit between the retention indices and the physicochemical properties. HPLC octadecylsilyl column with acetonitrile/water eluent was used for the estimation of S(w,L) and K(ow). Two GC columns, HP5-MS and a more hydrophobic HP-1, were tested for the estimation of P(v,L). Measured retention indices for the methylated naphthalenes were entered to the regression equations to calculate the physicochemical properties for these compounds. Literature values, where available, were used to validate the calculated values. The method accurately estimated the physicochemical properties. Estimated S(w,L) and P(v,L) decreased with the number of methyl groups. K(ow) increased with the number of methyl groups. There was no obvious relation between H(c) and the number of methyl groups. Log S(w,L) ranged from 0.885 for 1,2,5,6-tetramethylnaphthalene to 2.269 for 1-methylnaphthalene (mmol/m(3)). Log K(ow) varied from 3.89 for 1-methylnaphthalene to 4.95 for 1,2,5,6-tetramethylnaphthalene. Log P(v,L) ranged from -0.983 for 1,2,5,6-tetramethylnaphthalene to 0.789 for 2-methylnaphthalene (Pa). Log H(c) varied from 1.03 for 1,4,5-trimethylnaphthalene to 1.73 for 2,6-dimethylnaphthalene (Pa m(3)/mol). There were no apparent effects of GC column hydrophobicity on the accuracy of the results. Estimation of S(w,L) and K(ow) based on GC retention indices was not as accurate as with HPLC. Comparison of the estimated values with values predicted by EPIWIN indicated that EPIWIN is useful in giving order-of-magnitude prediction of physicochemical properties.     

Time as a constraint on group size in spider monkeys

An animal can only survive in a given habitat if it has enough time to find, process and digest food whilst avoiding predation. The time it has for food acquisition is affected by the vegetation and competition with conspecifics, which depends on aggregation tendencies. We used the relationships between time allocations, on the one hand, and climatic variables (as a proxy for habitat quality) and group size, on the other, to develop a model that predicts maximum ecologically tolerable group size at different locations for spider monkeys. Spider monkeys are particularly interesting because the social communities often split up into small units. Temperature variation and rainfall variation were the main determinants of time budgets. Community size and average annual rainfall determined party size. The model correctly predicted presence or absence of spider monkeys at 78–83% of 217 New World forest sites. Within the geographical range of the species, this time budget model predicted the presence of spider monkeys better than a model based directly on climate variables. Predicted community and party sizes were significantly larger at sites where spider monkeys are present than at sites where they are absent. As required by the model, predicted maximum community sizes were significantly larger than observed community sizes. Moving time showed a U-shaped relationship with party size, which suggests that moving time is the factor that keeps spider monkey communities from travelling together in a tight group.     

对生态系统中分离获得的菌种进行优势种群测定的方法学探讨：一株优势纤维分解菌的确定

两年内７次从同一个以杨木木屑为原料的厌氧发酵罐的高稀释度发酵液中分离出一株中温纤维分解菌，即新种阿氏梭状芽孢杆菌（Ｃｌｏｓｔｒｉｄｉｕｍａｌｄｒｉｃｈｉｉ）。从细菌计数高且能反复分离获得这两个特点，可以断定阿氏梭状芽孢杆菌在该生态系统中曾是一个优势种群。经菌落及菌体形态学观察，以及用首次分离的菌株所作的多价抗血清酶联免疫吸附试验（ＥＬＩＳＡ），确定７次分离菌株为同一菌种，从而证实阿氏梭状芽孢杆菌在１９８６年９月至１９８８年８月间，曾是该厌氧发酵罐中每毫升含菌高达１０６─１０７的优势纤维分解菌。     

Worker reproduction in the ponerine ant Ophthalmopone berthoudi: an alternative form of eusocial organization

Summary Colonies of the ponerine Ophthalmopone berthoudi were collected throughout the year. The queen caste is absent. Dissection of large numbers of workers revealed that many of them (up to 100 in one nest) are inseminated and produce eggs. The ovaries are small and contain very few mature oocytes, indicating that there is a slow rate of egg-laying. Workers are produced throughout the year, and all are capable of becoming functional reproductives. However, only those that are sexually-attractive during the limited period of male activity become mated. Thus the percentages of mated laying workers (=gamergates) fluctuate seasonally (Fig. 2). Successive generations of gamergates do not overlap. Observation of nests in the field and in the laboratory indicated that gamergates were never active above ground. There is no aggression between them, and their numbers are not socially regulated. There are few interactions between gamergates and non-reproductive workers, and the former do not acquire more food during termite meals. The notion of parental oppression is undermined by the complete loss of the meen caste, while the nature of the breeding system of this ant leads to the prediction of low relatedness between nestmates.     

Land use change around protected areas: management to balance human needs and ecological function.

Protected areas throughout the world are key for conserving biodiversity, and land use is key for providing food, fiber, and other ecosystem services essential for human sustenance. As land use change isolates protected areas from their surrounding landscapes, the challenge is to identify management opportunities that maintain ecological function while minimizing restrictions on human land use. Building on the case studies in this Invited Feature and on ecological principles, we identify opportunities for regional land management that maintain both ecological function in protected areas and human land use options, including preserving crucial habitats and migration corridors, and reducing dependence of local human populations on protected area resources. Identification of appropriate and effective management opportunities depends on clear definitions of: (1) the biodiversity attributes of concern; (2) landscape connections to delineate particular locations with strong ecological interactions between the protected area and its surrounding landscape; and (3) socioeconomic dynamics that determine current and future use of land resources in and around the protected area.     

Bird‐community responses to habitat creation in a long‐term,large‐scale natural experiment

Ecosystem function and resilience are compromised when habitats become fragmented due to land‐use change. This has led to national and international conservation strategies aimed at restoring habitat extent and improving functional connectivity (i.e., maintaining dispersal processes). However, biodiversity responses to landscape‐scale habitat creation and the relative importance of spatial and temporal scales are poorly understood, and there is disagreement over which conservation strategies should be prioritized. We used 160 years of historic post‐agricultural woodland creation as a natural experiment to evaluate biodiversity responses to habitat creation in a landscape context. Birds were surveyed in 101 secondary, broadleaf woodlands aged 10–160 years with ≥80% canopy cover and in landscapes with 0‐17% broadleaf woodland cover within 3000 m. We used piecewise structural equation modeling to examine the direct and indirect relationships between bird abundance and diversity, ecological continuity, patch characteristics, and landscape structure and quantified the relative conservation value of local and landscape scales for bird communities. Ecological continuity indirectly affected overall bird abundance and species richness through its effects on stand structure, but had a weaker influence (effect size near 0) on the abundance and diversity of species most closely associated with woodland habitats. This was probably because woodlands were rapidly colonized by woodland generalists in ≤10 years (minimum patch age) but were on average too young (median 50 years) to be colonized by woodland specialists. Local patch characteristics were relatively more important than landscape characteristics for bird communities. Based on our results, biodiversity responses to habitat creation depended on local‐ and landscape‐scale factors that interacted across time and space. We suggest that there is a need for further studies that focus on habitat creation in a landscape context and that knowledge gained from studies of habitat fragmentation and loss should be used to inform habitat creation with caution because the outcomes are not necessarily reciprocal.     

Heterogeneity of experts’ opinion regarding opportunities and challenges of tackling deforestation in the tropics: a Q methodology application

Making the concept of Reducing Emissions from Deforestation and Degradation (REDD+) ready to be a mechanism to combat tropical deforestation and associated greenhouse gas (GHG) emissions by compensating developing countries for income foregone in reducing their rates of deforestation, requires solutions for outstanding controversies. Existing opinions on REDD+ vary greatly. By using the Q-method as part of an action research approach, this paper investigates experts’ attitudes towards REDD+. Based on their responses to 41 statements, four attitudinal groups were identified, characterized as pragmatists, sceptics, conventionalists and optimists. Opinions between groups differed as to the level of application, credibility, eligibility, economic effectiveness, and public acceptability of REDD+ policy instruments. Three of the four groups were supportive of international REDD+ type policy interventions, but there was disagreement on the more concrete design issues of REDD+ projects, such as the allocation of responsibilities, the distribution of burdens and benefits, and whether or not co-benefits could be expected, or should be required. As the potential of REDD+ is shaped not only by international climate policy but also by national and regional policies and stakeholder perceptions, this paper suggests that participatory forms of decision-making may help to develop tailor-made solutions that are supported by the many different actors that are necessarily involved in REDD+ projects.     

Achieving a real-time online monitoring system for conservation culturomics

Environmental monitoring is increasingly shifting toward a set of systems that describe changes in real time. In ecology specifically, a series of challenges have prevented the rollout of real-time monitoring for features such as biodiversity change or ecosystem service provision. Conservation culturomics, a field concerned with interactions between people and nature, is well placed to demonstrate how monitoring might move toward a network of real-time platforms, given its existence exclusively in the digital realm. We examined a set of considerations associated with the development of real-time monitoring platforms for conservation culturomics and introduce a near real-time platform for the Species Awareness Index, a global index of changing biodiversity awareness derived from the rate of change in page views for species on Wikipedia. This platform will update automatically each month, operating in near real time ( https://joemillard.shinyapps.io/Real_time_SAI/ ). There are plans to make the underlying data queryable via an application programing interface independent of the platform. The real-time Species Awareness Index will represent the first real-time and entirely automated conservation culturomic platform and one of the first real-time platforms in the discipline of ecology. Real-time monitoring for culturomics can provide insight into human–nature interactions as they play out in the physical realm and provide a framework for the development of real-time monitoring in ecology. Real-time monitoring metrics can be processed on private virtual machines and hosted on publicly available cloud services. Conservation now needs an online, real-time observatory that can evolve with the structure of the web.