Following reports of dramatic declines in managed and feral honey bees from nearly every region of North America, scientists and resource managers from the U.S., Mexico, and Canada came together to review the quality of the evidence that honey bees as well as other pollinators are in long-term decline and to consider the potential consequences of these losses on the conservation of biodiversity and the stability of the yield of food crops. These experts in pollination ecology confirmed that the last 5 years of losses of honeybee colonies in North America leave us with fewer managed pollinators than at any time in the last 50 years and that the management and protection of wild pollinators is an issue of paramount importance to our food supply system. Although there are conclusive data that indicate 1200 wild vertebrate pollinators may be at risk, data on the status of most invertebrate species that act as pollination agents is lacking. The recommendations from a working group of over 20 field scientists, presented here, have been endorsed by 14 conservation and sustainable agriculture organizations, research institutes, and professional societies, including the Society for Conservation Biology. Among the most critical priorities for future research and conservation of pollinator species are (1) increased attention to invertebrate systematics, monitoring, and reintroduction as part of critical habitat management and restoration plans; (2) multi-year assessments of the lethal and sublethal effects of pesticides, herbicides, and habitat fragmentation on wild pollinator populations in and near croplands; (3) inclusion of the monitoring of seed and fruit set and floral visitation rates in endangered plant management and recovery plans; (4) inclusion of habitat needs for critically-important pollinators in the critical habitat designations for endangered plants; (5) identification and protection of floral reserves near roost sites along the “nectar corridors” of threatened migratory pollinators; and (6) investment in the restoration and management of a diversity of pollinators and their habitats adjacent to croplands in order to stabilize or improve crop yields. The work group encourages increased education and training to ensure that both the lay public and resource managers understand that pollination is one of the most important ecological services provided to agriculture through the responsible management and protection of wildland habitats and their populations of pollen-vectoring animals and nectar-producing plants. Consecuencias Potenciales de la Disminucion de Polinizadores en la Conservacion de la Biodiversidad y la Estabilidad en la Produccion de Cosechas de Alimentos Resumen: Debido a los constantes reportes de disminuciones dramaticas de abejas productoras de miel tanto manejadas como silvestres en casi todas las regiones de Norteamerica, cientificos y manejadores de recursos de Estados Unidos, Mexico y Canada se reunieron para revisar la calidad de las evidencias de que las abejas, asi como otros polinizadores se encuentran en una disminucion a largo plazo y para considerer las consecuencias potenciales de estas perdidas en la conservacion de la biodiversidad y la estabilidad de las cosechas de alimentos. Estos expertos en ecologia de la polinizacion confirmaron que los ultimos cinco anos de perdidas de colonias de abejas en Norteamerica nos ubican con menos polinizadores manejados que en ningun otro momento en los ultimos 50 anos y que el manejo y proteccion de polinizadores silvestres es un aspecto de suma importancia para nuestro sistema de abastecimiento de alimentos. A pesar de que existen datos concluyentes que indican que 1200 polinizadores vertebrados silvestres podrian encontrarse en riesgo, se carece de datos sobre la situacion de la mayoria de las especies de invertebrados que actuan como polinizadores. Las recomendaciones de un grupo de trabajo de mas de 20 cientificos, presentadas aqui, han sido respaldadas por 14 organizaciones de conservacion y agricultura sustentable, institutos de investigacion y sociedades de profesionistas incluyendo la Sociedad para la Biologia de la Conservacion. Entre las prioridades mas criticas de investigacion y conservacion de especies de polinizadores se encuentran; 1) incrementar el enfoque en sistematica de invertebrados, monitoreo y reintroduccion como parte del manejo de habitat critico y planes de restauracion; 2) evaluaciones de varios anos de los efectos letales y subletales de pesticidas, herbicidas y la fragmentacion del habitat en las poblaciones silvestres de polinizadores dentro y alrededor de las 10 Pollinator Declines Allen-Wardell et al. Conservation Biology Volume 12, No. 1, February 1998 tierras de cosechas; 3) inclusion del monitoreo de semillas y frutas y las tasas de visita en los planes de manejo y recuperacion de plantas; 4) inclusion de las necesidades de habitat para polinizadores criticamente importates en las designaciones de habitat critico para plantas amenazadas; 5) identification y proteccion de reservas florales cerca de sitios de percha a lo largo de “corredores de nectar” de polinizadores migratorios amenazados; y 6) inversion en la investigacion y manejo de una diversidad de polinizadores y sus habitats adyacentes a sitios con cosechas para poder estabilizar e improvisar la produccion de las cosechas. El grupo de trabajo hace un llamado para estimular un incremento en educacion y entrenamiento para asegurar que tanto el publico como los manejadores de recursos entiendan que la polinizacion es uno de los servicios ecologicos mas importantes aportados a la agricultura a traves del manejo responsable y la proteccion de habitats silvestres y de sus poblaciones de animales vectores de polen y plantas productoras de nectar.

The potential consequences of pollinator declines on the conservation of biodiversity and stability of food crop yields.

A new classification and conceptual framework for plant phenology are proposed to resolve problems in describing tropical patterns. A long-term (12 yr) survey of flowering in 254 lowland tropical rain forest trees of 173 species from the La Selva Biological Station in Costa Rica showed highly diverse, irregular, and complex patterns. Analysis of this survey data relied primarily on graphical analyses that provide data representation methods rather than numerical summaries that provide data reduction methods. The classification differs from previous ones in three ways. It uses, as the primary criterion, frequency of the time series, based on explicit time and amplitude scales, so that irregular temporal sequences are revealed. It features a system of subsidiary classes based on other quantitative descriptors: regularity, duration, amplitude, date, and synchrony. Finally, the conceptual framework separates patterns at each level of analysis so that adding the time series at one level produces a time series for the next higher level. Levels are hierarchical from the flower to the individual, population, and community with additional non-nested levels such as the guild. The four basic classes-continual, subannual, annual, and supra-annual--are applied to patterns at any level of analysis. The classification system provides a logical framework for quantitative description of phenological behavior leading to more standardized comparisons. Thus we can see that tropical phenology differs from temperate phenology in two major ways. In tropical species, the nature of the pattern may change from one level of analysis to the next, which is not typical of temperate species. In many tropical species, phenological patterns vary more widely over the geographic range of a species than they do in temperate species.

https://www.jstor.org/stable/pdfplus/2388804.pdf

A new classification for plant phenology based on flowering patterns in lowland tropical rain forest trees at La Selva, Costa Rica

Landscape mosaics and ecological theory. Origin of landscape pattern. Response of individuals and populations to landscape pattern. Landscape pattern, population dynamics and population genetics. Effects of landscape pattern on species interations. Implications for conservation. Summary: Ecology of mosaic landscapes: Consolidation, extension and application. Index.

Mosaic landscapes and ecological processes

Most plants combine sexual and clonal reproduction, and the balance between the two may vary widely between and within species. There are many anecdotal reports of plants that appear to have abandoned sex for clonal reproduction, yet few studies have quantified the degree of sexual variation in clonal plants and fewer still have determined the underlying ecological and/or genetic factors. Recent empirical work has shown that some clonal plants exhibit very wide variation in sexual reproduction that translates into striking variation in genotypic diversity and differentiation of natural populations. Reduced sexual reproduction may be particularly common at the geographical margins of species’ ranges. Although seed production and sexual recruitment may often be limited by biotic and abiotic aspects of the environment in marginal populations, genetic factors, including changes in ploidy and sterility mutations, may also play a significant role in causing reduced sexual fertility. Moreover, environmental suppression of sexual recruitment may facilitate the evolution of genetic sterility because natural selection no longer strongly maintains the many traits involved in sex. In addition to the accumulation of ‘neutral’ sterility mutations in highly clonal populations, the evolution of genetic infertility may be facilitated if sterility is associated with enhanced vegetative growth, clonal propagation or survival through either resource reallocation or pleiotropy. However, there are almost no experimental data with which to distinguish among these possibilities. Ultimately, wide variation in genotypic diversity and gene flow associated with the loss of sex may constrain local adaptation and the evolution of the geographical range limit in clonal plants.

The loss of sex in clonal plants

In the two decades since Janzen described how to be a fig, more than 200 papers have appeared on fig wasps (Agaonidae) and their host plants (Ficus spp., Moraceae). Fig pollination is now widely regarded as a model system for the study of coevolved mutualism, and earlier reviews have focused on the evolution of resource conflicts between pollinating fig wasps, their hosts, and their parasites. Fig wasps have also been a focus of research on sex ratio evolution, the evolution of virulence, coevolution, population genetics, host-parasitoid interactions, community ecology, historical biogeography, and conservation biology. This new synthesis of fig wasp research attempts to integrate recent contributions with the older literature and to promote research on diverse topics ranging from behavioral ecology to molecular evolution.

http://baloun.entu.cas.cz/png/WeiblenANNREVENT02.pdf

How to be a fig wasp

For plants with temporally separate sexual phases to outcross, population- level flowering asynchrony is necessary, but this can decrease the resource base available for pollinators. We developed a simulation model to examine the consequences of such asynchrony for individual reproductive success and long-term pollinator maintenance with- in monoecious fig populations. In figs, flowering is synchronous within a tree and the specialist pollinators/seed predators can only survive briefly away from trees. Consequently, population-level flowering asynchrony must extend year-round for pollinators to persist locally. In repeated stochastic simulations using phenological traits of one well-studied species (Ficus natalensis), a median of 95 trees was required to produce an asynchronous sequence that could maintain local pollinator populations for 4 yr. However, many trees in those simulated populations were either male-sterile (10%) or both male- and female- sterile (35%), because their sexual phases were not well timed with the opposite phases of other trees. Sterility within a population approached zero at 2-3 times the critical population size. Both the predicted critical population size and frequency of success of the trees within it depended strongly on the duration of reproductive episodes and the intervals between episodes. The level of within-tree reproductive synchrony was also critical: doubling the length of time over which individuals could donate pollen resulted in a 39% decrease in critical population size and a 27% increased likelihood that individuals would achieve at least some reproductive success. These results point to the need for precise phenological data for estimating plant fitness and population structure both in models and in the field.

/pdf/the-ecological-consequences-of-flowering-asynchrony-in-1hbt7h6r5c.pdf

The ecological consequences of flowering asynchrony in monoecious figs: a simulation study'

Genetic neighbourhoods in plants with diverse systems of mating and different patterns of growth

/pdf/genetic-neighbourhoods-in-plants-with-diverse-systems-of-3cxxl3hzzh.pdf

Chris Gliddon

Papers

The ecological consequences of flowering asynchrony in monoecious figs: a simulation study'

Genetic neighbourhoods in plants with diverse systems of mating and different patterns of growth