| 51. |
- Veen, Ciska
(författare)
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Grazing-induced changes in plant-soil feedback alter plant biomass allocation
- 2014
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 123, s. 800-806
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Tidskriftsartikel (refereegranskat)abstract
- Large vertebrate herbivores, as well as plant-soil feedback interactions are important drivers of plant performance, plant community composition and vegetation dynamics in terrestrial ecosystems. However, it is poorly understood whether and how large vertebrate herbivores and plant-soil feedback effects interact. Here, we study the response of grassland plant species to grazing-induced legacy effects in the soil and we explore whether these plant responses can help us to understand long-term vegetation dynamics in the field.In a greenhouse experiment we tested the response of four grassland plant species, Agrostis capillaris, Festuca rubra, Holcus lanatus and Rumex acetosa, to field-conditioned soils from grazed and ungrazed grassland. We relate these responses to long-term vegetation data from a grassland exclosure experiment in the field.In the greenhouse experiment, we found that total biomass production and biomass allocation to roots was higher in soils from grazed than from ungrazed plots. There were only few relationships between plant production in the greenhouse and the abundance of conspecifics in the field. Spatiotemporal patterns in plant community composition were more stable in grazed than ungrazed grassland plots, but were not related to plant-soil feedbacks effects and biomass allocation patterns.We conclude that grazing-induced soil legacy effects mainly influenced plant biomass allocation patterns, but could not explain altered vegetation dynamics in grazed grasslands. Consequently, the direct effects of grazing on plant community composition (e.g. through modifying light competition or differences in grazing tolerance) appear to overrule indirect effects through changes in plant-soil feedback.
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| 52. |
- von Euler, Tove, 1976-, et al.
(författare)
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Floral display and habitat quality affect cost of reproduction in Primula farinosa
- 2012
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 121:9, s. 1400-1407
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Tidskriftsartikel (refereegranskat)abstract
- Costs of reproduction should depend on resource availability and on reproductive effort, which in turn may depend on traits influencing reproductive success. Therefore, variation in both habitat quality and reproductive traits should be considered when assessing reproductive costs. We investigated the effect of habitat quality and floral display on the costs of reproduction in the perennial herb Primula farinosa. In the study area, P. farinosa occurs in habitats that differ in water availability, which strongly influences plant performance. Furthermore, it displays a scape length dimorphism, with two distinct scape morphs differing in attractiveness to pollinators and reproductive success. To test the hypothesis that the cost of fruit production is higher in the long-scaped than in the short-scaped morph, and depends on water availability, we manipulated reproductive investment in eight P. farinosa populations along a gradient of soil moisture. Fruit set was higher in long-scaped individuals, and prevention of fruit set increased flower production in the following year among long-scaped, but not among short-scaped plants. Furthermore, costs of fruit production were evident at low and high moisture levels but not at intermediate levels. The results demonstrate an association between a genetically determined difference in floral display and cost of reproduction, and suggest that costs of reproduction are non-linearly related to water availability. They thus indicate links between the evolution of plant reproductive traits and plant life histories, and between habitat quality and optimal life history.
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| 53. |
- Vrede, Tobias, et al.
(författare)
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Ecological stoichiometry of Eurasian perch : intraspecific variation due to size, habitat and diet
- 2011
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 120:6, s. 886-896
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Tidskriftsartikel (refereegranskat)abstract
- The turnover and distribution of energy and nutrients in food webs is influenced by consumer stoichiometry. Although the stoichiometry of heterotrophs is generally considered to vary only little, there may be intraspecific variation due to factors such as habitat, resources, ontogeny and size. We examined intraspecific variation in Eurasian perch Perca fluviatilis stoichiometry, a common species that exhibits habitat and resource specialization, ontogenetic niche shifts and a large size range. This study investigated the elemental stoichiometry of a wide size range of perch from littoral and pelagic habitats. The mean C:N:P stoichiometry of whole perch was 37:9:1 (molar ratios). However, %C, %P, C:N, C:P and N:P varied with size, morphology, habitat and diet category. These factors together explained 24–40% of the variation in C:N:P stoichiometry. In contrast, perch stoichiometry was not related to diet stoichiometry, suggesting that the former is homeostatically regulated. The results suggest that the high P content of perch may result in stoichiometric constraints on the growth of non-piscivorous perch, and that piscivory is an efficient strategy for acquiring P. Resource polymorphism, individual diet specialization and intraspecific size variation are widespread among animals. Thus changes in stoichiometry with size, habitat, morphology and resource use, and therefore also stoichiometric demands, are probably common.
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| 54. |
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| 55. |
- Zmihorski, Michal
(författare)
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Ecological correlates of the popularity of birds and butterflies in Internet information resources
- 2013
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 122, s. 183-190
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Tidskriftsartikel (refereegranskat)abstract
- The success of conservation programs depends on using appropriate methods to demonstrate the importance of conservation to society. For example, flagship species are among the key marketing tools to motivate public support. However, they are rarely selected in a systematic, manner. In this study we addressed the issue of the colonization of human information resources by birds and butterflies in the context of wildlife conservation. We used a simple method to measure the popularity of species based on Google browsing and made an attempt to link biological characteristics of the species with their popularity in human information resources. Biological traits of species contributed significantly to explaining the occupancy (invasion) of cyberspace by the species. Commonness and body size of the species appeared to be the most informative predictors of their Google score. We believe that these results may be used by conservation organizations to assist in the selection of flagship/charismatic species, and their use in logos, for TV programs or for other public presentations. Moreover, we showed that some biological traits can affect the popularity of wildlife in society and in virtual resources.
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| 56. |
- Abbott, Jessica, et al.
(författare)
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Insights from intralocus tactical conflict : adaptive states, interactions with ecology and population divergence
- 2019
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 128:11, s. 1525-1536
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Tidskriftsartikel (refereegranskat)abstract
- Alternative reproductive tactics (ARTs) have improved our understanding of the evolution of adaptive variation; for instance, their study has led us to understand that the best phenotype (e.g. large and flashy) for a tactic that uses one mating behavior (e.g. court females) is often not the best phenotype (e.g. small and inconspicuous) for a tactic that uses a different mating behavior (e.g. chase and force-copulate females). However, genetic correlations of shared traits across ARTs can constrain ARTs from reaching their optimal states, resulting in intralocus tactical conflict (IATC). While constraints on evolution in general have been well-established and studied, there are some important implications of constraints due to intralocus tactical conflict on ARTs that have not been incorporated into the field of evolutionary ecology. Here we describe how an appreciation of IATC, including how to detect it and when to expect it, can change our perspectives in three areas: 1) adaptive states for traits associated with ARTs (e.g. growth rates, behavioural plasticity); 2) how selection due to ecological variation across populations can produce patterns of divergence between ARTS; 3) and the evolutionary stability of polymorphisms (e.g. how IATC can explain losses of one ART, and why this can lead to rapid speciation).
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| 57. |
- Albert, Aurélie, et al.
(författare)
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Seed dispersal by ungulates as an ecological filter : a trait-based meta-analysis
- 2015
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 124:9, s. 1109-1120
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Tidskriftsartikel (refereegranskat)abstract
- Plant communities are often dispersal-limited and zoochory can be an efficient mechanism for plants to colonize new patches of potentially suitable habitat. We predicted that seed dispersal by ungulates acts as an ecological filter - which differentially affects individuals according to their characteristics and shapes species assemblages - and that the filter varies according to the dispersal mechanism (endozoochory, fur-epizoochory and hoof-epizoochory). We conducted two-step individual participant data meta-analyses of 52 studies on plant dispersal by ungulates in fragmented landscapes, comparing eight plant traits and two habitat indicators between dispersed and non-dispersed plants. We found that ungulates dispersed at least 44% of the available plant species. Moreover, some plant traits and habitat indicators increased the likelihood for plant of being dispersed. Persistent or nitrophilous plant species from open habitats or bearing dry or elongated diaspores were more likely to be dispersed by ungulates, whatever the dispersal mechanism. In addition, endozoochory was more likely for diaspores bearing elongated appendages whereas epizoochory was more likely for diaspores released relatively high in vegetation. Hoof-epizoochory was more likely for light diaspores without hooked appendages. Fur-epizoochory was more likely for diaspores with appendages, particularly elongated or hooked ones. We thus observed a gradient of filtering effect among the three dispersal mechanisms. Endozoochory had an effect of rather weak intensity (impacting six plant characteristics with variations between ungulate-dispersed and non-dispersed plant species mostly below 25%), whereas hoof-epizoochory had a stronger effect (eight characteristics included five ones with above 75% variation), and fur-epizoochory an even stronger one (nine characteristics included six ones with above 75% variation). Our results demonstrate that seed dispersal by ungulates is an ecological filter whose intensity varies according to the dispersal mechanism considered. Ungulates can thus play a key role in plant community dynamics and have implications for plant spatial distribution patterns at multiple scales.
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| 58. |
- Alpedrinha, João, et al.
(författare)
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The virtues and limitations of exploring the eco-evolutionary dynamics of sexually selected traits
- 2019
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 128:10, s. 1381-1389
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Tidskriftsartikel (refereegranskat)abstract
- Most studies on eco-evolutionary feedbacks concern the influence of abiotic factors, or predator-prey and host-parasite interactions, while studies involving sexual interactions are lagging behind. This is at odds with the potential of these interactions to engage in such processes. Indeed, there is now ample evidence that sexual selection is affected by ecological change and that sexually selected traits can evolve rapidly, which may modify the ecological context of populations, and thus the selection pressures they will be exposed to. Here we review evidence for such eco-evolutionary processes. We discuss examples of eco-evolutionary change in an attempt to understand the challenges related with identifying and characterizing such processes. In particular, we focus on the challenges associated with accurately identifying the components of the feedback as well as their causal relation. Finally, we evaluate scenarios where understanding eco-evolutionary feedbacks of sexual selection may help us appreciate the effects of sexual selection in shaping evolutionary processes.
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| 59. |
- Barthelemy, Hélène, 1986-, et al.
(författare)
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Defoliation of a grass is mediated by the positive effect of dung deposition, moss removal and enhanced soil nutrient contents : results from a reindeer grazing simulation experiment
- 2019
-
Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 128:10, s. 1515-1524
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Tidskriftsartikel (refereegranskat)abstract
- Herbivory is one of the key drivers shaping plant community dynamics. Herbivores can strongly influence plant productivity directly through defoliation and the return of nutrients in the form of dung and urine, but also indirectly by reducing the abundance of neighbouring plants and inducing changes in soil processes. However, the relative importance of these processes is poorly understood. We, therefore, established a common garden experiment to study plant responses to defoliation, dung addition, moss cover, and the soil legacy of reindeer grazing. We used an arctic tundra grazed by reindeer as our study system, and Festuca ovina, a common grazing-tolerant grass species as the model species. The soil legacy of reindeer grazing had the strongest effect on plants, and resulted in higher growth in soils originating from previously heavily-grazed sites. Defoliation also had a strong effect and reduced shoot and root growth and nutrient uptake. Plants did not fully compensate for the tissue lost due to defoliation, even when nutrient availability was high. In contrast, defoliation enhanced plant nitrogen concentrations. Dung addition increased plant production, nitrogen concentrations and nutrient uptake, although the effect was fairly small. Mosses also had a positive effect on aboveground plant production as long as the plants were not defoliated. The presence of a thick moss layer reduced plant growth following defoliation. This study demonstrates that grasses, even though they suffer from defoliation, can tolerate high densities of herbivores when all aspects of herbivores on ecosystems are taken into account. Our results further show that the positive effect of herbivores on plant growth via changes in soil properties is essential for plants to cope with a high grazing pressure. The strong effect of the soil legacy of reindeer grazing reveals that herbivores can have long-lasting effects on plant productivity and ecosystem functioning after grazing has ceased.
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| 60. |
- Bauerfeind, Stephanie S., et al.
(författare)
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Replicated latitudinal clines in reproductive traits of European and North American yellow dung flies
- 2018
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 127:11, s. 1619-1632
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Tidskriftsartikel (refereegranskat)abstract
- Geographic variation in phenotypic traits is commonly correlated with spatial variation in the environment, e.g. seasonality and mean temperature, providing evidence that natural selection generates such patterns. In particular, both body size and egg size of ectothermic animals are commonly larger in northern climates, and temperature induces plastic responses in both traits. Size-independent egg quality can also vary with latitude, though this is rarely investigated. For the widespread yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae) we investigated whether there are latitudinal clines in reproductive traits (clutch size, egg size and egg composition), whether these clines are due to variation in body and/or egg size, and whether such clines replicate across independent experiments performed on different continents (North America and Europe). Egg size generally increased with latitude (especially in Europe), an effect largely explained by body size of the mother, while clutch size did not; overall reproductive effort thus increased with latitude. Both the absolute and relative (correcting for egg size) amount of egg protein increased with latitude, egg glycogen decreased with latitude, while latitudinal trends for egg lipids and total egg energy content were complex and non-linear. Altitude sometimes showed relationships analogous to those of latitude (egg proteins and glycogen) but occasionally opposite (egg size), possibly because latitude and altitude are negatively related among populations of this cold-adapted species. There was no evidence of a tradeoff between egg size and number across latitudinal populations; if anything, the relationship was positive. All traits, including body and egg size, varied with rearing temperature (12 degrees C, 18 degrees C, 24 degrees C), generally following the temperature-size rule. Clines based on common garden rearing, thus reflecting genetic differentiation, were qualitatively but not always quantitatively consistent between continents, and were similar across rearing temperatures, suggesting they evolved due to natural selection, although the concrete selective mechanisms involved require further study.
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