Search results for "2303 Ecology"
showing 8 items of 8 documents
Within trophic level shifts in collagen-carbonate stable carbon isotope spacing are propagated by diet and digestive physiology in large mammal herbi…
2018
Stable carbon isotope analyses of vertebrate hard tissues such as bones, teeth, and tusks provide information about animal diets in ecological, archeological, and paleontological contexts. There is debate about how carbon isotope compositions of collagen and apatite carbonate differ in terms of their relationship to diet, and to each other. We evaluated relationships between δ13Ccollagen and δ13Ccarbonate among free-ranging southern African mammals to test predictions about the influences of dietary and physiological differences between species. Whereas the slopes of δ13Ccollagen–δ13Ccarbonate relationships among carnivores are ≤1, herbivore δ13Ccollag…
Social transmission of avoidance among predators facilitates the spread of novel prey.
2018
Warning signals are an effective defence strategy for aposematic prey, but only if they are recognized by potential predators. If predators must eat prey to associate novel warning signals with unpalatability, how can aposematic prey ever evolve? Using experiments with great tits (Parus major) as predators, we show that social transmission enhances the acquisition of avoidance by a predator population. Observing another predator’s disgust towards tasting one novel conspicuous prey item led to fewer aposematic than cryptic prey being eaten for the predator population to learn. Despite reduced personal encounters with unpalatable prey, avoidance persisted and increased over subsequent trials.…
Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster
2013
Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e., fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer t…
Shrines in Central Italy conserve plant diversity and large trees
2015
Sacred natural sites (SNS) are instances of biocultural landscapes protected for spiritual motives. These sites frequently host important biological values in areas of Asia and Africa, where traditional resource management is still upheld by local communities. In contrast, the biodiversity value of SNS has hardly been quantitatively tested in Western contexts, where customs and traditions have relatively lost importance due to modernization and secularization. To assess whether SNS in Western contexts retain value for biodiversity, we studied plant species composition at 30 SNS in Central Italy and compared them with a paired set of similar but not sacred reference sites. We demonstrate tha…
Ticket to spawn: Combining economic and genetic data to evaluate the effect of climate and demographic structure on spawning distribution in Atlantic…
2019
Abstract Climate warming and harvesting affect the dynamics of species across the globe through a multitude of mechanisms, including distribution changes. In fish, migrations to and distribution on spawning grounds are likely influenced by both climate warming and harvesting. The Northeast Arctic (NEA) cod (Gadus morhua) performs seasonal migrations from its feeding grounds in the Barents Sea to spawning grounds along the Norwegian coast. The distribution of cod between the spawning grounds has historically changed at decadal scales, mainly due to variable use of the northern and southern margins of the spawning area. Based on historical landing records, two major hypotheses have been put f…
Strontium Uptake and Intra-Population 87Sr/86Sr Variability of Bones and Teeth—Controlled Feeding Experiments With Rodents (Rattus norvegicus, Cavia …
2020
Strontium isotopes in biogenic apatite, especially enamel, are widely employed to determine provenance and track migration in palaeontology and archaeology. Body tissues record the 87Sr/86Sr of bioavailable Sr of ingested food and water. To identify non-local individuals, knowledge of the 87Sr/86Sr of a non-migratory population is required. However, varying factors such as tissue turnover rates, feeding selectivity, Sr content, digestibility of food, and the ingestion of mineral dust can influence body tissue 87Sr/86Sr. To evaluate the Sr contribution of diet and water to mammalian hard tissues 87Sr/86Sr, controlled feeding studies are necessary. Here we present 87Sr/86Sr from controlled fe…
Sun-induced fluorescence - a new probe of photosynthesis: First maps from the imaging spectrometer HyPlant.
2015
Variations in photosynthesis still cause substantial uncertainties in predicting photosynthetic CO2 uptake rates and monitoring plant stress. Changes in actual photosynthesis that are not related to greenness of vegetation are difficult to measure by reflectance based optical remote sensing techniques. Several activities are underway to evaluate the sun-induced fluorescence signal on the ground and on a coarse spatial scale using space-borne imaging spectrometers. Intermediate-scale observations using airborne-based imaging spectroscopy, which are critical to bridge the existing gap between small-scale field studies and global observations, are still insufficient. Here we present the first …
Diversification in evolutionary arenas - assessment and synthesis
2019
Abstract Understanding how and why rates of evolutionary diversification vary is a central issue in evolutionary biology and ecology. The concept of adaptive radiation has attracted much interest, but is metaphorical and verbal in nature, making it difficult to quantitatively compare different evolutionary lineages or geographic regions. In addition, the causes of evolutionary stasis are relatively neglected. Here we review the central concepts in the evolutionary diversification literature and bring these together by proposing a general framework for estimating rates of diversification and quantifying their underlying dynamics, which can be applied across clades and regions and across spat…