Christiaan Both (born 12 December 1969) is a Dutch Associate professor of ecology at the University of Groningen.
Christiaan Both was born in the Netherlands in 1969. From 1988 to 1993 he studied in various universities including Groningen, Oxford and Wageningen. In 1998 he graduated with a Ph.D. from the Netherlands Institute of Ecology and since that time worked as a postdoctoral researcher at Groningen, Bangor universities as well as University of California, Santa Cruz. In 2004 he joined Animal Ecology Group, a division of Groningen and three years later became Netherlands Organisation for Scientific Research's fellow. [1]
Christiaan Both studied density-dependent reproduction during his PhD, where he aimed to understand why birds lay smaller clutches when competition increased. This work was both using long-term data from hole-breeding passerines, and also experimental. It showed that great tit clutch size is causally affected by local density, and that the density dependent response could be explained by an optimal response of individuals to the level of competition for food during the nestling phase. [2]
From 1998 Christiaan Both, Niels Dingemanse, Piet Drent and Joost Tinbergen have studied great tits' exploration and showed that this variation in personality traits is heritable. [3] They were interested in how such variation with a heritable component could be maintained over evolutionary time, and therefore studied fitness consequences for three years in a wild population of great tits. The selection fluctated between years, between the sexes [4] and pair-combinations of personality were found to be important [5]
Since 2001 Christiaan mostly worked on the effects of climate change on trophic interactions, with an emphasis on changes phenology. Together with Marcel Visser he showed that climate change resulted in an insufficient response in timing of migration and egg-laying in the long-distance migratory pied flycatcher, [6] and that local populations declined as a result of increased asynchrony between breeding time and the date of the local food peak. [7] He is mostly interested in how different organisms can respond with different mechanisms and speeds to the high rates of current climate change, and the consequences this has for trophic interactions.
Corvidae is a cosmopolitan family of oscine passerine birds that contains the crows, ravens, rooks, magpies, jackdaws, jays, treepies, choughs, and nutcrackers. In colloquial English, they are known as the crow family or corvids. Currently, 139 species are included in this family. The genus Corvus containing 50 species makes up over a third of the entire family. Corvids (ravens) are the largest passerines.
Bird migration is a seasonal movement of birds between breeding and wintering grounds that occurs twice a year. It is typically from north to south or from south to north. Migration is inherently risky, due to predation and mortality.
The great tit is a small passerine bird in the tit family Paridae. It is a widespread and common species throughout Europe, the Middle East, Central Asia and east across the Palearctic to the Amur River, south to parts of North Africa where it is generally resident in any sort of woodland; most great tits do not migrate except in extremely harsh winters. Until 2005 this species was lumped with numerous other subspecies. DNA studies have shown these other subspecies to be distinct from the great tit and these have now been separated as two distinct species, the cinereous tit of southern Asia, and the Japanese tit of East Asia. The great tit remains the most widespread species in the genus Parus.
Helpers at the nest is a term used in behavioural ecology and evolutionary biology to describe a social structure in which juveniles and sexually mature adolescents of either one or both sexes remain in association with their parents and help them raise subsequent broods or litters, instead of dispersing and beginning to reproduce themselves. This phenomenon was first studied in birds where it occurs most frequently, but it is also known in animals from many different groups including mammals and insects. It is a simple form of co-operative breeding. The effects of helpers usually amount to a net benefit, however, benefits are not uniformly distributed by all helpers nor across all species that exhibit this behaviour. There are multiple proposed explanations for the behaviour, but its variability and broad taxonomic occurrences result in simultaneously plausible theories.
Christopher Miles Perrins, is Emeritus Fellow of the Edward Grey Institute of Field Ornithology at the University of Oxford, Emeritus Fellow at Wolfson College, Oxford and His Majesty's Warden of the Swans since 1993.
Species richness, or biodiversity, increases from the poles to the tropics for a wide variety of terrestrial and marine organisms, often referred to as the latitudinal diversity gradient. The latitudinal diversity gradient is one of the most widely recognized patterns in ecology. It has been observed to varying degrees in Earth's past. A parallel trend has been found with elevation, though this is less well-studied.
Avian malaria is a parasitic disease of birds, caused by parasite species belonging to the genera Plasmodium and Hemoproteus. The disease is transmitted by a dipteran vector including mosquitoes in the case of Plasmodium parasites and biting midges for Hemoproteus. The range of symptoms and effects of the parasite on its bird hosts is very wide, from asymptomatic cases to drastic population declines due to the disease, as is the case of the Hawaiian honeycreepers. The diversity of parasites is large, as it is estimated that there are approximately as many parasites as there are species of hosts. As research on human malaria parasites became difficult, Dr. Ross studied avian malaria parasites. Co-speciation and host switching events have contributed to the broad range of hosts that these parasites can infect, causing avian malaria to be a widespread global disease, found everywhere except Antarctica.
The Arctic lemming is a species of rodent in the family Cricetidae.
Ecological traps are scenarios in which rapid environmental change leads organisms to prefer to settle in poor-quality habitats. The concept stems from the idea that organisms that are actively selecting habitat must rely on environmental cues to help them identify high-quality habitat. If either the habitat quality or the cue changes so that one does not reliably indicate the other, organisms may be lured into poor-quality habitat.
In ecology, a priority effect refers to the impact that a particular species can have on community development as a result of its prior arrival at a site. There are two basic types of priority effects: inhibitory and facilitative. An inhibitory priority effect occurs when a species that arrives first at a site negatively affects a species that arrives later by reducing the availability of space or resources. In contrast, a facilitative priority effect occurs when a species that arrives first at a site alters abiotic or biotic conditions in ways that positively affect a species that arrives later. Inhibitory priority effects have been documented more frequently than facilitative priority effects. Studies indicate that both abiotic and biotic factors can affect the strength of priority effects.. Priority effects are a central and pervasive element of ecological community development that have significant implications for natural systems and ecological restoration efforts.
Serge Daan was a Dutch scientist, known for his significant contributions to the field of Chronobiology.
The match/mismatch hypothesis (MMH) was first described by David Cushing. The MMH "seeks to explain recruitment variation in a population by means of the relation between its phenology—the timing of seasonal activities such as flowering or breeding—and that of species at the immediate lower level". In essence, it is a measure of reproductive success due to how well the phenology of the prey overlaps with key periods of predator demand. In ecological studies, a few examples include timing and extent of overlap of avian reproduction with the annual phenology of their primary prey items, the interactions between herring fish reproduction and copepod spawning, the relationship between winter moth egg hatching and the timing of oak bud bursting, and the relationship between herbivore reproductive phenology with pulses in nutrients in vegetation.
Soundscape ecology is the study of the acoustic relationships between living organisms, human and other, and their environment, whether the organisms are marine or terrestrial. First appearing in the Handbook for Acoustic Ecology edited by Barry Truax, in 1978, the term has occasionally been used, sometimes interchangeably, with the term acoustic ecology. Soundscape ecologists also study the relationships between the three basic sources of sound that comprise the soundscape: those generated by organisms are referred to as the biophony; those from non-biological natural categories are classified as the geophony, and those produced by humans, the anthropophony.
Sexual selection in birds concerns how birds have evolved a variety of mating behaviors, with the peacock tail being perhaps the most famous example of sexual selection and the Fisherian runaway. Commonly occurring sexual dimorphisms such as size and color differences are energetically costly attributes that signal competitive breeding situations. Many types of avian sexual selection have been identified; intersexual selection, also known as female choice; and intrasexual competition, where individuals of the more abundant sex compete with each other for the privilege to mate. Sexually selected traits often evolve to become more pronounced in competitive breeding situations until the trait begins to limit the individual's fitness. Conflicts between an individual fitness and signaling adaptations ensure that sexually selected ornaments such as plumage coloration and courtship behavior are "honest" traits. Signals must be costly to ensure that only good-quality individuals can present these exaggerated sexual ornaments and behaviors.
In population ecology, Moran's theorem states that the time correlation of two separate populations of the same species is equal to the correlation between the environmental variabilities where they live.
Personality in animals has been investigated across a variety of different scientific fields including agricultural science, animal behaviour, anthropology, psychology, veterinary medicine, and zoology. Thus, the definition for animal personality may vary according to the context and scope of study. However, there is recent consensus in the literature for a broad definition that describes animal personality as individual differences in behaviour that are consistent across time and ecological context. Here, consistency refers to the repeatability of behavioural differences between individuals and not a trait that presents itself the same way in varying environments.
Capital breeding and income breeding refer to the methods by which some organisms perform time breeding and use resources to finance their breeding. The former "describes the situation in which reproduction is financed using stored capital; [whereas the latter] [...] refers to the use of concurrent intake to pay for a reproductive attempt."
Stuart Bearhop is a Professor of animal ecology at the University of Exeter. His research makes use of stable isotope analysis.
Significant work has gone into analyzing the effects of climate change on birds. Like other animal groups, birds are affected by anthropogenic (human-caused) climate change. The research includes tracking the changes in species' life cycles over decades in response to the changing world, evaluating the role of differing evolutionary pressures and even comparing museum specimens with modern birds to track changes in appearance and body structure. Predictions of range shifts caused by the direct and indirect impacts of climate change on bird species are amongst the most important, as they are crucial for informing animal conservation work, required to minimize extinction risk from climate change.
Urban evolution refers to the heritable genetic changes of populations in response to urban development and anthropogenic activities in urban areas. Urban evolution can be caused by mutation, genetic drift, gene flow, or evolution by natural selection. Biologists have observed evolutionary change in numerous species compared to their rural counterparts on a relatively short timescale.