646 research outputs found
Efficiency and effectiveness in representative reserve design in Canada: the contribution of existing protected areas
To be effective, reserve networks should represent all target species in protected areas that are large
enough to ensure species persistence. Given limited resources to set aside protected areas for biodiversity
conservation, and competing land uses, a prime consideration for the design of reserve networks is efficiency
(the maximum biodiversity represented in a minimum number of sites). However, to be effective,
networks may sacrifice efficiency. We used reserve selection algorithms to determine whether collections
of existing individual protected areas in Canada were efficient and/or effective in terms of representing
the diversity of disturbance-sensitive mammals in Canada in comparison to (1) an optimal network of
reserves, and (2) sites selected at random. Unlike previous studies, we restricted our analysis to individual
protected areas that met a criterion for minimum reserve size, to address issues of representation and
persistence simultaneously. We also tested for effectiveness and efficiency using historical and presentday
data to see whether protected area efficiency and/or effectiveness varied over time. In general, existing
protected areas did not effectively capture the full suite of mammalian species diversity, nor are most
existing protected areas part of a near-optimal solution set. To be effective, Canada’s network of reserves
will require at minimum 22 additional areas of >2700 km2. This study shows that even when only those
reserves large enough to be effective are considered, protected areas systems may not be representative,
nor were they representative at the time of establishment
Auditory appearances
It might be suggested that in auditory experience elements of the material world are not apparent to us in the way they are in vision and touch, and that this constitutes a shortcoming in the kind of cognitive contact with the world provided by auditory perception. I develop this suggestion, and then set out a way of thinking about the appearances of sound-producing events that might provide a response
The British Lithostrotiontidae
A revision and systematic study of the British species of the Carboniferous rugose coral family Lithostrotiontidae is described. No revision of this group has appeared since the middle of the last century. Results show that 15 described cerioid species of Lithostrotion can be lumped into four species. In addition L. decipiens depressum subsp. nov, is described in this group. The fasciculate species of Lithostrotion have been extended by the separation of L. variabile sp. nov., L. scaleberense sp, nov., L. junceum communicatum subsp. nov,, L. martini praenuntium subsp. nov. and L. martini simplex subsp. nov. The genus piphyphyllum is shown to be polyphyletically derived and its species are referred back to Lithostrotion. The monospecific genus Nemistium is considered synonymous with Lithostrotion and ranoved. Its one species is an evolutionary intermediate between two species of Lithostrotion. The genus Orionastraea is reviewed and 0. sera sp. nov. is described. Two species of Orionastraea are referred to Hadsonia gen, nov. which, though similar morphologically to Orionastraea, has a different ancestral species. H. matura Sp. nov. is described in this genua. The genus Aulina is excluded from the Lithostrotiontidae as it is thought to have different ancestors. It is restricted to include only forms with massive coralla and A. botanica sp. nov. and A. rotif ormis aphroidia subsp. nov, are described. Fasciculate species of Aulina are referred to Easoioaulina gen, nov. as they are apparently unrelated to Aulina sensu stricto. The phylogeny of the Lithostrotiontidae is described and shown to proceed by following certain evolutionary trends which lead to an increasing level of colonial it within the group. The evolutionary centre and therefore the palaeomigration directions of the Lithostrotiontidae are shown to change during the phylogeny and this is related to the global palaeogeography of the Carboniferous period. Discovery of well preserved material has allowed the skeletal changes during the hystero-ontogeny of L. martini to be determined. This revision has led to a better understanding of the species in the Lithostrotiontidae so that their value as statigraphical zonal indices has been increased
Incorporación de la incertidumbre en el diseño y aplicación de reglas de control de producción
Harvest control rules are widely used by management agencies for decision-making and for promoting public awareness of the status of marine and freshwater fisheries. Many current control rules combine fishing mortality and biomass-based biological reference points. Control rules were introduced as a precaution against the influence of uncertainty and to decrease the risk of overfishing, but are compromised if the uncertainties of the biological reference points are not explicitly considered. Uncertainty has been widely acknowledged but has not been incorporated into control rule design and application. In this paper, we used a Bayesian statistical catch-at-age model to estimate uncertainties in the indicators of fishing mortality, population size, and biological reference points. We apply this model to the Lake Erie walleye (Sander vitreus) fishery, and by fully considering the uncertainty of the indicators, the risk of overfishing and the risk of the population being overfished can be explicitly estimated in the control rules. We suggest short and long-term approaches to incorporate uncertainty in the design of control rules. We also suggest that control rules for specific fisheries should be designed with explicit consideration of the uncertainty of the biological reference points, based on a risk level that the management agency and stakeholders agree upon.Las reglas de control de producción se usan generalmente por los organismos de gestión de recursos pesqueros para tomar decisiones y para promover la concienciación pública sobre el estado de conservación de pesquerías marinas y de aguas dulces. Muchas de las reglas de control actuales combinan puntos de referencia biológicos basados en los indicadores mortalidad por pesca y biomasa. Las reglas de control fueron introducidas como precaución contra la influencia de la incertidumbre en las evaluaciones y para reducir el riesgo de sobrepesca, pero se ven comprometidas si la incertidumbre en los puntos de referencia biológicos no se consideran explícitamente. El papel de la incertidumbre se reconoce ampliamente, pero no ha sido incorporado hasta ahora en el diseño y aplicación de reglas de control. En la presente contribución se aplica un modelo bayesiano de capturas por edad para estimar la incertidumbre en los indicadores de mortalidad por pesca, tamaño de la población y puntos de referencia biológicos. Se aplica este modelo a la pesquería de Sander vitreus del Lago Erie, y, mediante la completa incorporación de la incertidumbre de los indicadores, el riesgo de sobrepesca puede ser estimado explícitamente en las reglas de control. Se sugieren aproximaciones a corto y largo plazo para la incorporación de la incertidumbre en el diseño de reglas de control. Se sugiere también que las reglas para pesquerías particulares deben diseñarse incorporando explícitamente la incertidumbre en los puntos de referencia biológicos, en base al nivel de riesgo que se acuerde entre el organismo encargado de la gestión del recurso y sus usuarios
The significance of the senses
Meeting of the Aristotelian Society, held in Senate House, University of London,
on Monday, 13th May, 2002, at 4.15 p.m.Standard accounts of the senses attempt to answer the question how
and why we count five senses (the counting question); none of the standard
accounts is satisfactory. Any adequate account of the senses must explain the
significance of the senses, that is, why distinguishing different senses matters. I
provide such an explanation, and then use it as the basis for providing an
account of the senses and answering the counting question
Kinds of experience and the five senses
In this paper I am going to argue that two commonly held views about perceptual
experience are incompatible and that one must be given up. The first is the view
that the five senses are to be distinguished by appeal to the kind of experiences
involved in perception; the second is the view – called Representationalism – that
the subjective character of perceptual experience is solely determined by what the
experience represents. We could take their incompatibility as a reason for
rejecting Representationalism; but I will suggest that it’s open to the
Representationalist to claim that the experiences of a single sense need have no
common character
Auditory Perception and Sounds
It is a commonly held view that auditory perception functions to tell us about
sounds and their properties. In this paper I argue that this common view is
mistaken and that auditory perception functions to tell us about the objects that
are the sources of sounds. In doing so, I provide a general theory of auditory
perception and use it to give an account of the content of auditory experience
and of the nature of sounds
The senses as psychological kinds
The distinction we make between five different senses is a universal one. Rather than
speaking of generically perceiving something, we talk of perceiving in one of five
determinate ways: we see, hear, touch, smell, and taste things. In distinguishing
determinate ways of perceiving things what are we distinguishing between? What, in
other words, is a sense modality? An answer to this question must tell us what
constitutes a sense modality and so needs to do more than simply describe differences in
virtue of which we can distinguish the perceptions of different senses. There are many
such differences – the different perceptions involve different sense organs, sensitivity to
different kinds of stimuli, the perception of different properties, and they involve
different kinds of experiences – but which, if any, of these differences are the differences
that really matter
What Are Auditory Objects?
Forthcoming in European Review of Philosophy, 7Our auditory experience involves the experience of auditory objects sequences of distinct sounds, or parts of sounds, that are experienced as grouped together into a single sound or stream or sounds. In this paper I argue that argue that we cannot explain what it is to experience an auditory object in purely auditory terms; rather, to experience an auditory object as such is to experience a sequence of sounds as having been produced by the same source
Sounds and Space
Forthcoming publication in Auditory Perception and SoundsWhere are sounds are where do we percieve them to be? In what follows I argue that when we hear them sounds are where we are, but that we don't hear them to be where we are because we don't hear them to be anywhere. This conclusion follows the account I give (in section 1) of what sounds are and (in section 2) of the role of space in auditory perception
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