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101.
M. Koopmans P. van Rijswijk D. Martens T. A. Egorova-Zachernyuk J. J. Middelburg R. H. Wijffels 《Marine Biology》2011,158(1):9-20
The carbon metabolism of two marine sponges, Haliclona oculata and Dysidea avara, has been studied using a 13C isotope pulse-chase approach. The sponges were fed 13C-labeled diatoms (Skeletonema costatum) for 8 h and they took up between 75 and 85%. At different times, sponges were sampled for total 13C enrichment, and fatty acid (FA) composition and 13C enrichment. Algal biomarkers present in the sponges were highly labeled after feeding but their labeling levels decreased
until none was left 10 days after enrichment. The sponge-specific FAs incorporated 13C label already during the first day and the amount of 13C label inside these FAs kept increasing until 3 weeks after labeling. The algal-derived carbon captured by the sponges during
the 8-h feeding period was thus partly respired and partly metabolized during the weeks following. Apparently, sponges are
able to capture enough food during short periods to sustain longer-term metabolism. The change of carbon metabolic rate of
fatty acid synthesis due to mechanical damage of sponge tissue was studied by feeding sponges with 13C isotope–labeled diatom (Pheaodactylum tricornutum) either after or before damaging and tracing back the 13C content in the damaged and healthy tissue. The filtration and respiration in both sponges responded quickly to damage. The
rate of respiration in H. oculata reduced immediately after damage, but returned to its initial level after 6 h. The 13C data revealed that H. oculata has a higher metabolic rate in the tips where growth occurs compared to the rest of the tissue and that the metabolic rate
is increased after damage of the tissue. For D. avara, no differences were found between damaged and non-damaged tissue. However, the filtration rate decreased directly after
damage. 相似文献
102.
Colby J. Tanner Gül Deniz Salalι Andrew L. Jackson 《Behavioral ecology and sociobiology》2011,65(2):249-256
Human activity can have a large impact on surrounding ecosystems. For example, humans alter resource distributions for other
species, potentially modifying these species competitive dynamics. These changes in local competitive processes are frequently
associated with species invasions. Here, we investigate how differences in resource distribution affect competitive behaviour
using the highly invasive European shore crab (Carcinus maenas). Using a controlled laboratory experiment in combination with behaviour assays and social network analysis, we show that
individuals feeding in habitats with clumped food distributions are more aggressive than individuals feeding in habitats where
food is evenly dispersed, and this aggression is present even on days where crabs are not feeding. Additionally, this persistent
aggression can be induced, suggesting that individuals of this invasive species possess the flexibility to modify their competitive
behaviours in response to differences in food distributions. Furthermore, we show how these individual responses can lead
to changes in overall organisation of aggressive interactions within a population. We discuss these results in relation to
how human impacts can have long-term effects on competitive behavioural strategies, and how behavioural flexibility can allow
invasive species to colonise and persist in highly impacted sites such as urban ecosystems. 相似文献
103.
Judith Morales Alberto Velando Roxana Torres 《Behavioral ecology and sociobiology》2011,65(2):197-203
Avian eggshell color is remarkably variable among and within species and its possible function has long been controversial.
Female birds use biliverdin pigment to color their eggs blue and green. Although evidence is accumulating that blue-green
eggshell coloration is costly to produce, the exact mechanisms underlying its expression are little studied. Biliverdin pigment
is involved in important maintenance functions such as immune and antioxidant defenses and shows similar properties to carotenoid
pigments. Carotenoids play a role as immunoenhancers and have the potential to ameliorate the impact of oxidative processes,
although their antioxidant function could be minor for some bird species. Important life-history components can be limited
by carotenoid availability, including sexual displays and fecundity. Here we explored if biliverdin-based eggshell pigmentation
was affected by carotenoid availability in a seabird, by performing a carotenoid supplementation experiment in female blue-footed
boobies (Sula nebouxii) after laying their first egg. In this species, blue eggshell color is associated with incubation patterns, and carotenoid
availability affects the crucial trade-off between female foot ornamentation and fecundity. We found that under natural conditions,
there was a decline in eggshell color with laying order, suggesting pigment limitation for females. However, carotenoid-supplemented
females had enhanced second egg coloration compared to controls, and the color increase was independent of their previous
pigment allocation to the first egg. Our results suggest that biliverdin-based eggshell coloration is costly to produce and
can be alleviated by current carotenoid availability. 相似文献
104.
Alex Kacelnik Marco Vasconcelos Tiago Monteiro Justine Aw 《Behavioral ecology and sociobiology》2011,65(3):547-558
Charles Darwin aided his private decision making by an explicit deliberation, famously deciding whether or not to marry by
creating a list of points in a table with two columns: “Marry” and “Not Marry”. One hundred seventy-two years after Darwin’s
wedding, we reconsider whether this process of choice, under which individuals assign values to their options and compare
their relative merits at the time of choosing (the tug-of-war model), applies to our experimental animal, the European Starling,
Sturnus vulgaris. We contrast this with the sequential choice model that postulates that decision-makers make no comparison between options
at the time of choice. According to the latter, behaviour in simultaneous choices reflects adaptations to contexts with sequential
encounters, in which the choice is whether to take an opportunity or let it pass. We postulate that, in sequential encounters,
the decision-maker assigns (by learning) a subjective value to each option, reflecting its payoff relative to background opportunities.
This value is expressed as latency and/or probability to accept each opportunity as opposed to keep searching. In simultaneous
encounters, choice occurs through each option being processed independently, by a race between the mechanisms that generate
option-specific latencies. We describe these alternative models and review data supporting the predictions of the sequential
choice model. 相似文献
105.
James A. R. Marshall 《Behavioral ecology and sociobiology》2011,65(3):503-512
Reconciling the evolution of altruism with Darwinian natural selection is frequently presented as a fundamental problem in
biology. In addition to an exponentially increasing literature on specific mechanisms that can permit altruism to evolve,
there has been a recent trend to establish general principles to explain altruism in populations undergoing natural selection.
This paper reviews and extends one approach to understanding the ultimate causes underlying the evolution of altruism and
mechanisms that can realise them, based on the Price equation. From the Price equation, we can see that such ultimate causes
equate to the different ways in which the frequency of an altruistic allele in a population can increase. Under this approach,
the ultimate causes underlying the evolution of altruism, given some positive fitness costs and benefits, are positive assortment
of altruistic alleles with the altruistic behaviour of others, positive deviations from additive fitness effects when multiple
altruists interact or bias in the inheritance of altruistic traits. In some cases, one cause can be interpreted in terms of
another. The ultimate causes thus identified can be realised by a number of different mechanisms, and to demonstrate its general
applicability, I use the Price equation approach to analyse a number of classical mechanisms known to support the evolution
of altruism (or cooperation): repeated interaction, ‘greenbeard’ traits, games played on graphs and payoff synergism. I also
briefly comment on other important points for the evolution of altruism, such as the ongoing debate over the predominant status
of inclusive fitness as the best way to understand its evolution. I conclude by arguing that analysing the evolution of altruism
in terms of its ultimate causes is the logical way to approach the problem and that, despite some of its technical limitations,
the Price equation approach is a particularly powerful way of doing so. 相似文献
106.
AIC model selection and multimodel inference in behavioral ecology: some background,observations, and comparisons 总被引:4,自引:0,他引:4
Kenneth P. Burnham David R. Anderson Kathryn P. Huyvaert 《Behavioral ecology and sociobiology》2011,65(1):23-35
We briefly outline the information-theoretic (I-T) approaches to valid inference including a review of some simple methods
for making formal inference from all the hypotheses in the model set (multimodel inference). The I-T approaches can replace
the usual t tests and ANOVA tables that are so inferentially limited, but still commonly used. The I-T methods are easy to compute and
understand and provide formal measures of the strength of evidence for both the null and alternative hypotheses, given the
data. We give an example to highlight the importance of deriving alternative hypotheses and representing these as probability
models. Fifteen technical issues are addressed to clarify various points that have appeared incorrectly in the recent literature.
We offer several remarks regarding the future of empirical science and data analysis under an I-T framework. 相似文献
107.
Maria Clara P. Amorim José Miguel Simões Vitor C. Almada Paulo J. Fonseca 《Behavioral ecology and sociobiology》2011,65(4):707-716
Signal attributes should show different degrees of variability depending on the information to be conveyed. Species identity
is usually associated with stereotyped features of a signal, whereas other types of information such as individual quality
and motivation are associated with signal plasticity. Lusitanian toadfish males form aggregations during the breeding season
and emit a tonal advertisement call (the boatwhistle) to attract mates to their nests. We test the hypothesis that the boatwhistle
can convey information both on individual identity and motivation by checking how signal parameters vary with time. We study
how the physical (tide level) and social (calling alone or in a chorus) environments and male calling rate affect this advertisement
signal and how all these external and internal factors (environment, social and male motivation) blend to modulate the Lusitanian
toadfish’s advertisement call. Boatwhistles of each male were very stereotyped in short periods of time (minutes), but intra-male
signal variability greatly increased in a longer time scale (days). Nevertheless, significant differences among males could
still be found even in a long time scale. Pulse period was the acoustic feature that most contributed to discriminate among
males. Tide level and male calling rate modulated boatwhistle characteristics, and there was a differential effect of tide
on call attributes depending on male calling rate. Social acoustic environment only affected calling rate. These results suggest
that inter-individual differences in call characteristics and call plasticity may mediate both male–male assessment and mate
choice. 相似文献
108.
This paper describes the application of coastal hydro-informatic modelling (using the TELEMAC Modelling System) to address
management issues arising from projected hydrodynamical and morphological changes within a shallow, sandy estuarine environment.
The model incorporates the complex interaction of ocean, terrestrial and atmospheric processes. The case study of the Dyfi
Estuary, on the west coast of Wales, is highlighted here. As sea levels have risen locally and are predicted to rise further,
a National Nature Reserve (Borth Bog), which has been reclaimed from tidal waters by embankments, will be at increasing risk
from flooding episodes due to overtopping of these embankments at high tide. Present and predicted future tidal-fluvial scenarios
have been modelled in the Dyfi Estuary in order to estimate the potential for flooding. In addition, areas of greatest velocity
change and potential for sediment erosion/accretion have been identified. A further process that has been investigated is
how salt marsh migration is affected by sea-level rise. This case study exemplifies some fundamental and complex physical
processes inherent to estuaries, and shows how different management options can be assessed, before their implementation,
through a modelling approach. 相似文献
109.
Sam Provoost M. Laurence M. Jones Sally E. Edmondson 《Journal of Coastal Conservation》2011,15(1):207-226
In coastal dunes, landscape changes are a rule, rather than an exception. This paper gives an overview of changes in landscape
and vegetation with a focus on the past century. The history of dunes is characterised by phases of sand drift, alternated
with geomorphological stability. The historical development of dune woodland during these stable phases has been documented
for sites all over Europe. Vegetation reconstructions of historical open dune habitats however is very difficult due to limited
preservation of fossil remains. People have drastically altered coastal dune landscapes through centuries of exploitation
and more recently development of the coast. Historical land use has generally pushed vegetation back into a semi-natural state.
During roughly the past century a tendency of increasing fixation and succession is observed on coastal dunes throughout northwest
Europe. Six causes of change are discussed. 1) Changes in land use, mainly abandonment of agricultural practices, have led
to the development of late successional stages such as scrub and woodland. 2) Crashing rabbit populations due to myxomatosis
in the 1950s caused vigorous grass growth and probably stimulated scrub development. 3) A general tendency of landscape fixation
is observed due to both natural and anthropogenic factors. 4) Eutrophication, mainly due to atmospheric nitrogen deposition
is clearly linked to grass encroachment on acidic but also on some calcareous dunes. 5) The impact of climate change on vegetation
is still unclear but probably lengthening of growing season and maybe enhanced CO2 concentrations have led to an acceleration of succession. 6) A general anthropogenisation of the landscape occurs with rapid
spread of non-native species as an important consequence. The reconstruction of a natural reference landscape is considered
largely unattainable because of irreversible changes and the long tradition of human impact, in many cases since the development
of the dunes. Two contradictory elements need reconciliation. First, the general acceleration of succession and scrub and
woodland development in particular is partly caused by a decreased anthropogenic interference in the landscape and deserves
more appreciation. Second, most biodiversity values are largely linked to open, early succession dune habitats and are threatened
by the same tendency. Apart from internal nature management, in which grazing plays an important part, re-mobilisation of
stable, senescent dunes is an important challenge for dune management. 相似文献
110.
The Turks and Caicos Islands are currently in the midst of an economic revolution from a marine-based provisional economy to a tourism economy. East Bay, South Caicos, is currently under construction with plans for a 160-unit condominium complex. Included in the project plan is removal of seagrass beds in front of the development to make a sandy beach for tourists. The aims of this study were to (i) describe the bathymetry and benthic habitat coverage of East Bay before dredging takes place and (ii) perform an economic valuation on the turtle grass beds that will be dredged using ecosystem valuation and emergy analysis techniques. The bathymetry survey revealed shallow waters (<1.5 m) until the reef drop off (~650 m offshore). Benthic habitat exhibits zonation following the general progression: sand plain, algal plain, seagrass, coral rubble and seagrass, rock and turf algae, and reef flat. Ecosystem services valued the proposed dredging area at USD $28,807 per year, compared to emergy analysis, which valued the proposed dredging site at USD $32,060 per year. The baselines presented in the study may facilitate a quantitative assessment of dredging impacts on turtle grass once dredging is complete and an economical cost-benefit-analysis of the dredging project to see whether the economic gains outweigh the ecological costs of dredging in front of the East Bay development. 相似文献