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1.
Current Normative Concepts in Conservation   总被引:5,自引:0,他引:5  
A plethora of normative conservation concepts have recently emerged, most of which are ill-defined: biological diversity, biological integrity, ecological restoration, ecological services, ecological rehabilitation, ecological sustainability, sustainable development, ecosystem health, ecosystem management, adaptive management, and keystone species are salient among them. These normative concepts can be organized and interpreted by reference to two new schools of conservation philosophy, compositionalism and functionalism. The former comprehends nature primarily by means of evolutionary ecology and considers Homo sapiens separate from nature. The latter comprehends nature primarily by means of ecosystem ecology and considers Homo sapiens a part of nature. Biological diversity, biological integrity, and ecological restoration belong primarily in the compositionalist glossary; the rest belong primarily in the functionalist glossary. The former set are more appropriate norms for reserves, the latter for areas that are humanly inhabited and exploited. In contrast to the older schools of conservation philosophy, preservationism and resourcism, compositionalism and functionalism are complementary, not competitive and mutually exclusive. As the historically divergent ecological sciences—evolutionary ecology and ecosystem ecology—are increasingly synthesized, a more unified philosophy of conservation can be envisioned.  相似文献   

2.
This article explores features of the environmental valuation process through a co-evolutionary approach. Based on established works concerning complexity, living systems, and social, economic, evolutionary and hierarchy theories, it is argued that a special form of recursive co-evolution takes place between articulated values and methods of value articulation, within the environmental valuation system. It is proposed that this co-evolutionary approach provides new insights into (1) the process of environmental preference formation and (2) the phenomenon of value incommensurability. Finally, it is suggested that this approach also reveals that monetary unit-based environmental valuation methods are counter-productive to their own purpose of 'taking the economic worth of un-priced environmental goods and service into account.' This constitutes a new critique of monetary valuation, which is not addressed by a pragmatic defence of the practice. It is suggested that, in lieu of monetary valuation, taking the economic worth of these phenomena into account may be better served by focusing efforts on the design of new value articulation methods that are capable of expressing their priceless economic worth.  相似文献   

3.
A number of scholars, mainly in ecological economics, have been attracted to the concept of co-evolution for the analysis of socio-environmental change. Yet none has adopted and developed an applied analytical approach using an explicitly evolutionary framework. This paper discusses how other scholars in economics, technological studies, organization and political science have been using evolutionary explanations and draws some lessons for ecological economics. Evolutionary is a mode of explanation based on the selective retention of renewable variation. It accounts for phenomena of structural fit and change in a variety of domains. A co-evolutionary explanation, by extension, entails two or more evolving systems whose interaction affects their evolution. Socio-environmental co-evolution involves human systems (material practices and non-material ideas and values) and non-human systems (living and physical). The challenge then is how to develop case-specific, empirical applications that define and elaborate the variants that co-evolve and specify the processes of mutual selection. Applications could benefit from existing classifications and causal propositions in the natural and social sciences. Co-evolution is part of a larger analytical toolkit for looking at complex socio-environmental problems. Although distinct, there are strong synergies, complementarities and potential for combined uses between co-evolutionary, co-dynamic and complexity-based explanations.  相似文献   

4.
Faced with an intermittent but potent threat, animals exhibit behavior that allows them to balance foraging needs and avoid predators and over time, these behaviors can become hard-wired adaptations with both species trying to maximize their own fitness. In systems where both predator and prey share similar sensory modalities and cognitive abilities, such as with marine mammals, the dynamic nature of predator-prey interactions is poorly understood. The costs and benefits of these anti-predator adaptations need to be evaluated and quantified based on the dynamic engagement of predator and prey. Many theoretic models have addressed the complexity of predator-prey relationships, but few have translated into testable mechanistic models. In this study, we developed a spatially-explicit, geo-referenced, individual-based model of a prototypical adult dusky dolphin off Kaikoura, New Zealand facing a more powerful, yet infrequent predator, the killer whale. We were interested in two primary objectives, (1) to capture the varying behavioral game between a clever prey and clever predator based on our current understanding of the Kaikoura system, (2) to compare evolutionary costs vs. benefits (foraging time and number of predator encounters) for an adult non-maternal dusky dolphin at various levels of killer whale-avoidance behaviors and no avoidance rules. We conducted Monte Carlo simulations to address model performance and parametric uncertainty. Mantel tests revealed an 88% correlation (426 × 426 distance matrix, km2) between observed field sightings of dusky dolphins with model generated sightings for non-maternal adult dusky dolphin groups. Simulation results indicated that dusky dolphins incur a 2.7% loss in feeding time by evolving the anti-predator behavior of moving to and from the feeding grounds. Further, each evolutionary strategy we explored resulted in dolphins incurring an additional loss of foraging time. At low killer whale densities (appearing less than once every 3 days), each evolutionary strategy simulated converged towards the evolutionary cost of foraging, that is, the loss in foraging time approached the 2.7% loss experienced by evolving near shore-offshore movement behavior. However, the highest level of killer whale presence resulted in 38% decreases in foraging time. The biological significance of these losses potentially incurred by a dusky dolphin is dependent on various factors from dolphin group foraging behavior and individual energy needs to dolphin prey availability and behavior.  相似文献   

5.
Fricke  H.  Hissmann  K. 《Marine Biology》2000,136(2):379-386
One concept of evolutionary ecology holds that a living fossil is the result of past evolutionary events, and is adapted to recent selective forces only if they are similar to the selective forces in the past. We describe the present environment of the living coelacanth Latimeria chalumnae Smith, 1939 at Grande Comore, western Indian Ocean and report depth-dependent cave distribution, temperature, salinity and oxygen values which are compared to the fish's distribution and its physiological demands. We studied the activity pattern, feeding behaviour, prey abundance and hunting success to evaluate possible links between environmental conditions, feeding ecology and evolutionary success of this ancient fish. Transmitter tracking experiments indicate nocturnal activity of the piscivorous predator which hunts between approximately 200 m below the surface to 500 m depth. Fish and prey density were measured between 200 and 400 m, both increase with depth. Feeding tracks and feeding strikes of the coelacanth at various depths were simulated with the help of video and laser techniques. Along a 9447 m video transect a total of 31 potential feeding strikes occurred. Assuming 100% hunting success, medium-sized individuals would obtain 122 g and large females 299 g of prey. Estimates of metabolic rates revealed for females 3.7 ml O2 kg−1 h−1 and for males 4.5 ml O2 kg−1 h−1. Today coelacanths are considered to be a specialist deep-water form and to inhabit, with their ancient morphology, a contemporary environment where they compete with advanced, modern fish. Received: 5 July 1999 / Accepted: 11 November 1999  相似文献   

6.
Summary. Chemical signals frequently underlie sexual isolation between insect species. Our understanding of the evolutionary forces influencing these signaling systems is known for very few systems, challenging both our efforts to understand insect speciation, and our ability to predict long-term changes in the chemical communication systems of insects. Thus, we are in need of more systems in which both the chemical signals causing sexual isolation and the evolutionary forces driving sexual isolation are understood. Sexual isolation in the hybrid zone between Chrysochus cobaltinus and C. auratus has apparently increased in response to natural selection against hybridisation (i.e. reinforcement). Previous experiments suggested that this isolation was due, at least in part, to male preferences for conspecific females. Here, we confirm this role of male choice, and document that male mate choice in this system is influenced by cuticular hydrocarbon (CHC) profiles. Specifically, male C. cobaltinus responses to control cadavers and conspecific female cadavers painted with different cuticular hexane extracts, together with analyses of the composition of those extracts, revealed that male mate choice is governed by CHC profiles. Multivariate analyses of GC profiles demonstrated that those profiles are indeed both sex- and species-specific. Although GC-MS enabled identification and quantification of the specific cuticular hydrocarbons, we have not yet determined which individual compounds govern mate choice. Having established that CHCs influence sexual isolation in this system, we can now assess the evolutionary lability of these cues, which will inform both our understanding of speciation, and of the conditions under which the chemical signaling systems that influence mate choice in insects can evolve.  相似文献   

7.
Many species of platyrrhine primates are characterised by sex-linked color vision polymorphism. This presents an opportunity to study the biology and ecology of individuals with different phenotypes living in the same group. Several evolutionary processes could maintain polymorphic genes in populations. In this study, we evaluate the hypothesis that foraging niche divergence among monkeys explains the presence of multiple color vision phenotypes. Specifically, we test whether dichromats and trichromats differ in foraging time devoted to cryptic vs brightly colored resources. We did not find any differences in foraging time spent on different food types by dichromatic and trichromatic monkeys in two groups of white-faced capuchins (Cebus capucinus) living in a tropical dry forest. We conclude that in so far as these variables are concerned, niche divergence does not likely explain color vision polymorphism in our study population.  相似文献   

8.
Mechanistic simulation modeling has not generally delivered on its promise to turn ecology into more of a “hard” science. Rather, it appears that deeper insights into ecosystem functioning may derive from a new set of metaphysical assumptions about how nature functions. Force laws from physics are fundamentally incompatible with the heterogeneity and uniqueness that characterizes ecosystems. Instead, coherence, selection and centripetality are imparted to ecological systems by concatenations of beneficial processes—a generalized form of autocatalysis. These structure-enhancing configurations of processes are opposed by the ineluctable tendency of structure to decay (as required by the second law of thermodynamics). The dual nature of this agonism can be quantified using information theory, which also can be used to measure the potential of the system for further evolution. The balance point for these countervailing tendencies seems to coincide with the state of maximal potential for the system to evolve. In an ostensible paradox, the same locus seems to attract stable, persistent system configurations.  相似文献   

9.
The concept of sustainable cities is based on a development paradigm that recognizes that cities make an important contribution to social and economic development. System thinking, including hard and soft systems, can be used to provide a new perspective and tools to resolve questions. The 500-year-old heritage city of Udaipur in India, which has traditionally maintained the spirit of living in a sustainable manner, is now seeking sustainable development. This paper attempts to analyse the issues underlying sustainable development of Udaipur by applying CATWOE in order to comprehend the systemic elements of the city from a soft systems perspective.  相似文献   

10.
Is complexity growth the result of a continuous process or a sudden breakthrough? An increased energy density rate is the effect or the cause of a complexity leap? Should we approach complexity change by the perspective of components behaviour or system's space geometry? In this work we address some of the questions regarding the theoretical approach to complexity change. For this purpose a case study drawn by the productive structure and the transport system is considered. We would like here to propose an example in which the system structure is reshaped in a more energy intensive fashion as to increase the components’ interactions due to a symmetry rupture in the space. Flows throughout the system are thereby incremented in a discontinuous way by a complexity leap. In the case study, we analyze how the productive system evolved its structure, between 1970s and 1990s, to increase interactions among its parts and thus further develop the transport sub-system. A two-stage shift has been considered: the fordian and the post-fordian productive structure. The second structure, given the same amount of parts, has been shown to increase the degree of freedom (path length and path diversity) of the system. The underlying evolutionary pattern is then analyzed. This evolutionary pattern relies on the hypothesis that thermodynamic evolutionary systems are characterized by an ever growing influx of energy driven into the system by self-catalytic processes that must find their way through the constraints of the system. The system initially disposes of the energy by expanding, in extent and in the number of components, up to saturation due to inner or outer constraints. The two counteractive forces, constraints and growing energy flux, expose the system to new gradients. Every new (spatial) gradient upon the system represents a symmetry rupture in the components’ space. By exploring a new gradient, the system imposes further restrictions on its components and increases its overall degree of freedom. The counteractive effects of reduction/increase of degree of freedom concern two different hierarchical levels and occur at two different space and time scales.  相似文献   

11.
The Paradox of Forest Fragmentation Genetics   总被引:5,自引:0,他引:5  
Abstract:  Theory predicts widespread loss of genetic diversity from drift and inbreeding in trees subjected to habitat fragmentation, yet empirical support of this theory is scarce. We argue that population genetics theory may be misapplied in light of ecological realities that, when recognized, require scrutiny of underlying evolutionary assumptions. One ecological reality is that fragment boundaries often do not represent boundaries for mating populations of trees that benefit from long-distance pollination, sometimes abetted by long-distance seed dispersal. Where fragments do not delineate populations, genetic theory of small populations does not apply. Even in spatially isolated populations, where genetic theory may eventually apply, evolutionary arguments assume that samples from fragmented populations represent trees that have had sufficient time to experience drift, inbreeding, and ultimately inbreeding depression, an unwarranted assumption where stands in fragments are living relicts of largely unrelated predisturbance populations. Genetic degradation may not be as important as ecological degradation for many decades following habitat fragmentation.  相似文献   

12.
Sperm transfer via spermatophores is common among organisms living in mesopsammic environments, and is generally considered to be an evolutionary adaptation to reproductive constraints in this habitat. However, conclusions about adaptations and trends in insemination across all interstitial taxa cannot be certain as differences in mode of insemination via spermatophores do exist, details of insemination are lacking for many species, and evolutionary relationships in many cases are poorly known. Opisthobranch gastropods typically transfer sperm via reciprocal copulation, but many mesopsammic Acochlidia are aphallic and transfer sperm via spermatophores, supposedly combined with dermal fertilisation. The present study investigates structural and functional aspects of sperm transfer in the Mediterranean microhedylacean acochlid Pontohedyle milaschewitchii. We show that spermatophore attachment is imprecise. We describe the histology and ultrastructure of the two-layered spermatophore and discuss possible functions. Using DAPI staining of the (sperm-) nuclei, we document true dermal insemination in situ under the fluorescence microscope. Ultrastructural investigation and computer-based 3D reconstruction from TEM sections visualise the entire spermatozoon including the exceptionally elongate, screw-like keeled sperm nucleus. An acrosomal complex was not detected. From their special structure and behaviour we conclude that sperm penetrate epithelia, tissues and cells mechanically by drilling rather than lysis. Among opisthobranchs, dermal insemination is limited to mesopsammic acochlidian species. In this spatially limited environment, a rapid though imprecise and potentially harmful dermal insemination is discussed as a key evolutionary innovation that could have enabled the species diversification of microhedylacean acochlidians.  相似文献   

13.
The genetic structure of a population is closely connected to fundamental evolutionary processes and aspects of social behavior. Information on genetic structure is therefore instrumental for the interpretation of social behavior and evolutionary reconstructions of social systems. Gray mouse lemurs (Microcebus murinus) are basal primates endemic to Madagascar whose social organization is characterized by solitary foraging at night and communal resting during the day. Conflicting reports about population structure based on behavioral observations led us to examine the genetic structure of one population in detail in order to: (1) identify natural genetic units in this solitary primate, and (2) to test the assumption of current models of primate social evolution that solitary primates are organized in matrilines. DNA was extracted from tissue samples of 85 individuals from Kirindy forest to determine their variability at a 530 bp fragment of the mitochondrial D-loop and at six microsatellite loci. We found that this population was characterized by a great general diversity among mtDNA haplotypes, a pronounced sex difference in mtDNA haplotype diversity and spatial clustering of females with a particular haplotype, but low average relatedness among members of haplotype clusters. Specifically, we identified 13 different haplotypes, which were unevenly distributed among individuals. About 80% of all individuals, most of which were females or juvenile males, shared a single haplotype. Rare haplotypes were almost exclusively represented by single adult males, who apparently migrated into this population. One other haplotype was represented by a small group of females living at one edge of the study area. Microsatellite analysis revealed above-average relatedness among females with overlapping home ranges, as well as no signs of inbreeding, implying that male dispersal results in high levels of gene flow among matrilineal groups. We conclude that gray mouse lemur populations are hierarchically organized in small family units of closely related females that form stable sleeping groups, several of which are connected through a common mtDNA haplotype and form spatially distinct clusters. The presence of such matrilines supports a basic assumption of current models of primate social evolution.  相似文献   

14.
Rethinking Crop Genetic Resource Conservation   总被引:1,自引:0,他引:1  
Abstract: A worldwide system of crop germplasm conservation has been developed around ex situ preservation This system is based on a dual mandate of conservation and development; and it has largely ignored the farming systems that produce germplasm A revisionist critique of the existing system is presented Problems of the current strategy include incomplete collection loss within these collections, isolation from evolutionary processes, and budgetary constraints. In situ conservation offers an alternative to current methods, especially if conservation rather than development is the priority. The concept of genetic erosion is discussed and evaluated in light of recent evidence of uneven change in areas of crop diversity. Farmers in many parts of the world are conserving traditional varieties even as they modernize and adopt improved varieties. This pattern is illustrated by reference to Asian rice agriculture. A new approach to conservation is needed that builds a collaborative program between farmers, crop scientists, ecologists, biogeographers, and social scientists. A first step is to analyze farming systems that already conserve traditional crop varieties.  相似文献   

15.
The known chemical basis of diverse avian eggshell coloration is generated by the same two classes of tetrapyrrole pigments in most living birds. We aimed to extend the evolutionary scope of these patterns by detecting pigments from extinct birds’ eggs. In our samples biliverdin was successfully extracted from subfossil shell fragments of the blue-green egg-laying upland moa Megalapteryx didinus, while protoporphyrin was extracted from the beige eggs of two other extinct moa species. Our data on pigment detection from eggshells of other extant paleognath birds, together with published information on other modern lineages, confirm tetrapyrroles as ubiquitous and conserved pigments contributing to diverse eggshell colours throughout avian evolution.  相似文献   

16.
17.
钒是一种重要的生命冗索,同时也是环境污染物之一,因此环境样品及生命有机体中微量钒的测定具有重要的实际意义,是预测和评估其对人体健康、环境发全影响的重要前提之一。环境中钒主要以Ⅳ价和V价存在,因而对钒的测定方法研究主要集中在Ⅳ和Ⅴ价化合物的分离分析上,对Ⅴ(Ⅴ)和Ⅴ(Ⅳ)的分离方法,和光谱法、催化动力法、极谱法、酶学反应法等测定Ⅴ(Ⅴ)、Ⅴ(Ⅳ)和Ⅴ的方法进行了综述。  相似文献   

18.
E. Tiezzi 《Ecological modelling》2011,222(16):2897-2902
This paper collects, with few minor formal changes, two of the latest scientific contributions ( [Tiezzi, 2006a] and [Tiezzi et al., 2010]) written by Prof. Enzo Tiezzi, where he introduced new concepts and tools to formalize and understand the role of thermodynamics in ecosystems theory.Particular attention is devoted to goal functions, to the relation of matter, energy, space and time and to the interdisciplinary approach connecting thermodynamics and biology. Entropy is discussed as a fundamental goal function in the far from equilibrium framework. The relationship between entropy, as a non-state function, and the state-function energy is stressed and discussed, at the light of the role of information. The theory of probability is also discussed in the light of new theoretical findings related to the role of events, also in terms of entropy and evolutionary thermodynamics.Confined Ontic Open Systems (COOS) represent the latest model proposed by Prof. Tiezzi based on his Ecodynamic theory, evolutionary thermodynamics, Ulanowicz's ontic. The model has a wide range of applications, including ecosystems, ecological economics, urban organization, the supra-molecular structure of water and global biosphere's models. The model is explained in terms of evolutionary thermodynamics and Jørgensen's ecosystems theory.  相似文献   

19.
Interactions between water and land in The Netherlands   总被引:1,自引:0,他引:1  
The Netherlands are one of the most densely populated coastal countries in the world and there is only limited space for living, working, transport and recreation, while there is also the need to preserve and expand valuable natural habitats. In order to solve many existing and future conflicts of interest, and in order to create ‘added value’, strategies are developed to optimize the use of water-land systems. The principle of ‘building with nature’ is applied in order to integrate land in sea and water in land in such a way that future generations will be able to use coastal resources in a sustainable way, including a minimal effort to maintain the coastline and the promotion of a multiple-use system. The concept of Integrated multifunctional sustainable coastal zone development is introduced. This concept deals with a balanced approach to the lack of space for present and future coastal uses in relation to each other, to the hinterland, and to the sea. Flexible master plans are developed, taking into account many functions of the coastal zone, and facilitating adaptation to future developments—e.g. impacts of climate change and relative sea level rise. In this regard increasing the flexibility of the coastal zone is of vital importance. Large-scale coastal land reclamations in The Netherlands are dealt with, based on two different principles: (1) polder systems (low lying land reclamations surrounded and protected by dikes), (2) systems of ‘building with nature’—land reclamation protected by man-made foreshores, beaches and dunes. In the latter type new flexible dynamic-equilibrium coasts are created for many functions, while coastal vulnerability is reduced and a flexible coast is developed.  相似文献   

20.
The extent of diversity within closely related taxa may be a function of their shared evolutionary history or of selective forces causing adaptive changes. Examining variation among taxa within a single genus may help to identify flexibility in trait variation because recently diverged populations are more likely living in the environment of adaptation. This study examines correlates of diversity in Eulemur, a genus that has a wide distribution in a variety of habitat types throughout Madagascar. Previously published data were gathered from 11 long-term studies of Eulemur populations. Variables were categorized into multiple datasets: (1) environmental characteristics, (2) social organization, and (3) ecology, which included subsets for ranging behavior, diet, and activity budget. Molecular phylogenies from the literature were used to create the fourth and final dataset, a dissimilarity matrix of evolutionary distance among the 12 species and subspecies. Principal components and cluster analyses were implemented to examine the overall ecological similarity among Eulemur populations and to determine which variables contribute most to the variation among taxa. Partial Mantel tests were conducted to test for correlations among the dataset matrices. The results suggest ecological flexibility for the genus, in particular, populations in similar environments displayed similar activity patterns. In contrast, social organization showed no relationship with environment but was correlated with phylogenetic distance among populations. While Eulemur seems to demonstrate some flexibility for ecological adaptations, characteristics related to group size and sex ratio more closely track phylogeny and thus may be less flexible.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible to authorized users.  相似文献   

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