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1.
We analyzed the patterns of total, endangered and exotic fish species richness in 80 reservoirs throughout Japan using Generalized
Linear Models (GLMs) with variables of dam characteristics (e.g. reservoir size, isolated period, altitude, DO, pH, rainfall,
and air temperature) and watershed characteristics (e.g. watershed area, human population, and land-use patterns). Exotic
species richness was positively correlated with total species richness but negatively correlated with endangered species richness.
Largemouth bass, rainbow trout, and bluegill were the three most widely distributed species, occupying 47.5, 37.5, and 33.8%
of the reservoirs, respectively. The patterns of total and endangered species richness were largely explained by watershed
area and annual air temperature. Exotic species richness was determined primarily by the proportion of developed areas within
each watershed. Therefore, reservoirs in more developed areas tend to support more exotic fish species that in turn threaten
endangered fish species more severely.
相似文献
Takehiko FukushimaEmail: |
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Peter McHugh Phaedra Budy Gary Thiede Erin VanDyke 《Environmental Biology of Fishes》2008,81(1):63-75
Nonnative trout invasions have caused the widespread decline of cutthroat trout populations in western North America. In contrast
to other nonnative salmonids, the role of nonnative brown trout in native cutthroat trout decline is poorly understood. Specifically,
the level of ecological similarity that occurs between these species and the importance of other trophic mechanisms (e.g.,
predation) in their interactions are key uncertainties. We evaluated the trophic relationships of brown trout and cutthroat
trout in a northern Utah river using a combination of diet and stable isotope analyses. We compared the dietary habits of
these two species using multiple and complementary measures. Based on both stomach contents and δ13C signatures, we found that these species consumed a similar and opportunistic diet (i.e., they were nonselective in their
foraging patterns). However, at most sizes, brown trout ingested larger prey—including fishes—and occupied a higher relative
trophic position (i.e., δ15N) than cutthroat trout. Overall, these results demonstrate a high degree of dietary similarity and therefore strengthen earlier
conclusions regarding interspecific competition between these two species. Our study, when considered alongside the work of
others, suggests there is potential for predatory interactions between these species (i.e., brown trout preying on small cutthroat
trout). We believe that future research on brown trout–cutthroat trout interactions should consider predatory effects in greater
detail.
相似文献
Peter McHughEmail: |
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5.
Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.
相似文献
Marienne S. de VilliersEmail: Fax: +27-21-6503434 |
John CooperEmail: |
Peter G. RyanEmail: |
6.
Jonathan J. Goin Thomas H. Williams Christopher J. Donohoe 《Environmental Biology of Fishes》2008,82(3):207-213
Vertebral counts in fishes are set early in development by a complex interaction of genetic and environmental factors. Recently,
R. M. McDowall showed that vertebral counts can differ between diadromous and non-diadromous galaxiids, and suggested similar
life history-based variation might also occur in the closely related Salmonidae. We examined variation in vertebral counts
of juvenile rainbow trout, Oncorhynchus mykiss, from within a single large basin where anadromous and non-anadromous forms co-occur. Juveniles were collected at 29 sites
within the Klamath River basin using a nested sampling design. Mean vertebral counts varied among regions, among complexes
within regions, and among sites within complexes. Regression showed that mean vertebral counts decreased with increasing distance
from the ocean. This decrease could not be explained by differences in temperature within the basin during early development.
However, the decrease is consistent with the expectation that non-anadromous forms have fewer vertebrae and are more common
at sites distant from the ocean, and suggests that further study of the relationship between vertebral counts and life history
form in O. mykiss is warranted.
相似文献
Thomas H. WilliamsEmail: |
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The recent contribution by Jarmila Kukalová-Peck on Hennigian phylogenetics and hexapod limb evolution is critically evaluated.
相似文献
Michael S. Engel (Corresponding author)Email: |
9.
To our knowledge, this paper is the first record/report of a juvenile light-coloured Weddell seal (Leptonychotes weddellii) at Cape Shirreff, Livingston Island in January 1998, determining that it was an albino individual. Based on available literature,
three cases of albino seals have been reported exclusively for Harbour seal pups, and no albino has been reported for Antarctic
pagophilic true seals. Therefore, this is the first confirmed case of albinism in Antarctic pagophilic true seals species,
indicating that this phenomenon is indeed of a rare occurrence.
相似文献
Daniel TorresEmail: |
10.
A key point in the analysis of dynamical models of biological systems is to handle systems of relatively high dimensions.
In the present paper we propose a method to hierarchically organize a certain type of piecewise affine (PWA) differential
systems. This specific class of systems has been extensively studied for the past few years, as it provides a good framework
to model gene regulatory networks. The method, shown on several examples, allows a qualitative analysis of the asymptotic
behavior of a PWA system, decomposing it into several smaller subsystems. This technique, based on the well-known strongly
connected components decomposition, is not new. However, its adaptation to the non-smooth PWA differential equations turns
out to be quite relevant because of the strong discrete structure underlying these equations. Its biological relevance is
shown on a 7-dimensional PWA system modeling the gene network responsible for the carbon starvation response in Escherichia coli.
相似文献
Laurent Tournier (Corresponding author)Email: |
Jean-Luc GouzéEmail: |
11.
Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
相似文献
Peter Godfrey-SmithEmail: |
12.
Terry Harmer 《Cluster computing》2007,10(3):277-285
Gridcast is an R&D project investigating grid ideas and technologies in the broadcasting technical infrastructure. In this
paper I discuss the business and technical issues in building infrastructures to support broadcasters and outline the structure
of the Gridcast grid-based service oriented architecture for broadcasting playout support.
相似文献
Terry HarmerEmail: |
13.
Machado RR Lima Filho ES Jardim DF Ferreira MA de Faria CG Duarte RS Lesche B 《European biophysics journal : EBJ》2008,38(1):111-119
An interferometer that measures the refractive index changes due to bacterial metabolism is described. The apparatus permits
simultaneous and real time measurement of bacterial growth in several samples of slowly growing mycobacteria. The error sources
are discussed and the sensitivity of the apparatus is tested. For the species Mycobacterium bovis BCG and M. smegmatis, a relation between refractive index change and bacterial concentration is determined experimentally and the time constant
of bacterial growth is measured.
相似文献
B. LescheEmail: |
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15.
T. Ryan Gregory 《Evolution》2008,1(4):358-389
The origin of complex biological structures has long been a subject of interest and debate. Two centuries ago, natural explanations
for their occurrence were considered inconceivable. However, 150 years of scientific investigation have yielded a conceptual
framework, abundant data, and a range of analytical tools capable of addressing this question. This article reviews the various
direct and indirect evolutionary processes that contribute to the origins of complex organs. The evolution of eyes is used
as a case study to illustrate these concepts, and several of the most common misconceptions about complex organ evolution
are discussed.
相似文献
T. Ryan GregoryEmail: |
16.
Roger Sansom 《Biology & philosophy》2008,23(4):475-491
I show that gene regulation networks are qualitatively consistent and therefore sufficiently similar to linearly seperable
connectionist networks to warrant that the connectionist framework be applied to gene regulation. On this view, natural selection
designs gene regulation networks to overcome the difficulty of development. I offer some general lessons about their evolvability
that can be learned by examining the generic features of connectionist networks.
相似文献
Roger SansomEmail: |
17.
Natalia V. Ivanova Aron J. Fazekas Paul D. N. Hebert 《Plant Molecular Biology Reporter》2008,26(3):186-198
Many plant species are considered difficult for DNA isolation due to their high concentrations of secondary metabolites such
as polysaccharides and polyphenols. Several protocols have been developed to overcome this problem, but they are typically
time-consuming, not scalable for high throughput and not compatible with automation. Although a variety of commercial kits
are available for plant DNA isolation, their cost is high and these kits usually have limited taxonomic applicability. In
a previous study we developed an inexpensive automation-friendly protocol for DNA extraction from animal tissues. Here we
demonstrate that a similar protocol allows DNA isolation from plants.
相似文献
Natalia V. IvanovaEmail: |
18.
Causal Explanation of Indonesian Forest Fires: Concepts, Applications, and Research Priorities 总被引:1,自引:0,他引:1
Andrew P. Vayda 《Human ecology: an interdisciplinary journal》2006,34(5):615-635
Problems with studies, claims, and assumptions that have been made about the causes of fires in Indonesia's tropical moist forests are identified, and the kinds of concepts, methods, prioritizing, and data needed to resolve the problems are discussed. Separate sections are devoted to studying ignitions, studying fire susceptibility and fire behavior, and using the goal of causal explanation to guide interdisciplinary research.
相似文献
Andrew P. VaydaEmail: |
19.
Event-related brain potentials (ERP) are important neural correlates of cognitive processes. In the domain of language processing,
the N400 and P600 reflect lexical-semantic integration and syntactic processing problems, respectively. We suggest an interpretation
of these markers in terms of dynamical system theory and present two nonlinear dynamical models for syntactic computations
where different processing strategies correspond to functionally different regions in the system’s phase space.
相似文献
Peter beim GrabenEmail: |
20.
Strategies of abstraction 总被引:2,自引:1,他引:1
Richard Levins 《Biology & philosophy》2006,21(5):741-755
Abstraction is seen as an active process which both enlightens and obscures. Abstractions are not true or false but relatively
enlightening or obscuring according to the problem under study; different abstractions may grasp different aspects of a problem.
Abstractions may be useless if they can answer questions only about themselves. A theoretical enterprise explores reality
through acluster of abstractions that use different perspectives, temporal and horizontal scales, and assumes different givens.
相似文献
Richard LevinsEmail: |