Search results for "Study"
showing 10 items of 15483 documents
Condition-dependent skipped spawning in anadromous brown trout (Salmo trutta)
2018
Repeat spawners of anadromous salmonids may contribute significantly to population resilience by providing multiple cohorts to both seawater and freshwater life stages. In this study, winter survival of sea trout (Salmo trutta Linnaeus, 1758) post spawners (kelts) was 89%. Sea survival increased linearly with female length with a return probability between 30% and 50%, whereas males attained a maximum return probability of 60% at 520 mm. Of the returning sea trout, 40% skipped spawning and they had significantly lower condition factor as kelts compared with those who returned after one summer. These results suggest that sex-specific differences in individual post-spawning growth–survival t…
Forty-five years later: The shifting dynamic of traditional ecological knowledge on Pantelleria Island, Italy
2016
In 1969, Galt and Galt conducted an ethnobotanical survey in the community of Khamma on the volcanic island of Pantelleria, Italy. Since then, a number of botanical studies concerning the local wild flora and cultivation of the zibibbo grape and capers have been conducted, but none have investigated traditional ecological knowledge (TEK) regarding the use of wild plants and fungi. We documented the current TEK and practices concerning wild plants and fungi on the island, focusing on uses related to food and medicine with 42 in-depth interviews in six communities in June 2014. Our aim was to examine shifts in TEK, represented in terms of loss or gain of specific species uses, in comparison t…
Voles and weasels in the boreal Fennoscandian small mammal community : What happens if the least weasel disappears due to climate change?
2019
Climate change, habitat loss and fragmentation are major threats for populations and a challenge for individual behavior, interactions and survival. Predator–prey interactions are modified by climate processes. In the northern latitudes, strong seasonality is changing and the main predicted feature is shortening and instability of winter. Vole populations in the boreal Fennoscandia exhibit multiannual cycles. High amplitude peak numbers of voles and dramatic population lows alternate in 3–5‐year cycles shortening from North to South. One key factor, or driver, promoting the population crash and causing extreme extended lows, is suggested to be predation by the least weasel. We review the ar…
Demographic responses of a site-faithful and territorial predator to its fluctuating prey: long-tailed skuas and arctic lemmings.
2014
Summary1. Environmental variability, through interannual variation in food availability or climaticvariables, is usually detrimental to population growth. It can even select for constancy in keylife-history traits, though some exceptions are known. Changes in the level of environmentalvariability are therefore important to predict population growth or life-history evolution.Recently, several cyclic vole and lemming populations have shown large dynamical changesthat might affect the demography or life-histories of rodent predators.2. Skuas constitute an important case study among rodent predators, because of theirstrongly saturating breeding productivity (they lay only two eggs) and high deg…
Predator encounters have spatially extensive impacts on parental behaviour in a breeding bird community.
2016
Predation risk has negative indirect effects on prey fitness, partly mediated through changes in behaviour. Evidence that individuals gather social information from other members of the population suggests that events in a community may impact the behaviour of distant individuals. However, spatially wide-ranging impacts on individual behaviour caused by a predator encounter elsewhere in a community have not been documented before. We investigated the effect of a predator encounter (hawk model presented at a focal nest) on the parental behaviour of pied flycatchers ( Ficedula hypoleuca ), both at the focal nest and at nearby nests different distances from the predator encounter. We show tha…
How Do Infanticidal Male Bank Voles (Myodes glareolus) Find the Nest with Pups?
2016
Infanticide, the killing of conspecific young, occurs in most mammal species, like in our study species, the bank vole (Myodes glareolus). Infanticide by adult males is regarded as a strong factor affecting recruitment of young into population. It is considered as an adaptive behaviour, which may increase male fitness via resource gain or an increased access to mates. When an intruder is approaching the nest, the mother should not be present, as her nest guarding is very aggressive and successful. Pups use ultrasonic vocalisation to call their mother when mother leaves nest for foraging but it is not know which cues do infanticidal males use to find the nest with vulnerable pups to commit i…
Dispersal ecology of deadwood organisms and connectivity conservation
2016
Limited knowledge of dispersal for most organisms hampers effective connectivity conservation in fragmented landscapes. In forest ecosystems, deadwood-dependent organisms (i.e., saproxylics) are negatively affected by forest management and degradation globally. We reviewed empirically established dispersal ecology of saproxylic insects and fungi. We focused on direct studies (e.g., mark-recapture, radiotelemetry), field experiments, and population genetic analyses. We found 2 somewhat opposite results. Based on direct methods and experiments, dispersal is limited to within a few kilometers, whereas genetic studies showed little genetic structure over tens of kilometers, which indicates long…
Fragmentation-related patterns of genetic differentiation in pedunculate oak (<i>Quercus robur</i>) at two hierarchical scales
2016
Populations at speciesâ range margins are expected to show lower genetic diversity than populations at the core of the range. Yet, long-lived, widespread tree species are expected to be resistant to genetic impoverishment, thus showing comparatively high genetic diversity within populations and low differentiation among populations. Here, we study the distribution of genetic variation in the pedunculate oak ( L.) at its range margin in Finland at two hierarchical scales using 15 microsatellite loci. At a regional scale, we compared variation within versus among three oak populations. At a landscape scale, we examined genetic structuring within one of these populations, growing on an islan…
Use of sewage sludge compost and Trichoderma asperellum isolates to supress Fusarium wilt of tomato
2002
It has been reported that plant growth media amended with composted bark suppress Fusarium wilts whereas media amended with composted municipal sludge aggravate this disease. However, in this study, a compost prepared from vegetable and animal market wastes, sewage sludge and yard wastes showed a high ability to suppress Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici race 1. The ability of this compost to suppress Fusarium wilt of tomato was compared with that of a peat mix (peat:vermiculite, 1:1 v/v) and a naturally suppressive soil from Chateaurenard, France. The compost and the soil from Chateaurenard were highly suppressive, whereas the peat mix was highly condu…
Cause and duration of mustard incorporation effects on soil-borne plant pathogenic fungi
2009
International audience; Two fungal plant pathogens, Rhizoctonia solani AG 2-2 and Fusarium oxysporum f.sp. lini, were studied in relation to general responses of soil fungi and bacteria following incorporation of Brassica juncea. Our aim was to understand to what extent the changes in the biological and physicochemical characteristics of the soil could explain the effects on the studied pathogens and diseases, and to determine the temporal nature of the responses. Short-term effects of mustard incorporation (up to 4 months) were investigated in a microcosm experiment, and compared with a treatment where composted plant material was incorporated. In a field experiment, the responses were fol…