Search results for "010601 ecology"

Conservation implications of change in antipredator behavior in fragmented habitat: Boreal rodent, the bank vole, as an experimental model

2015

Abstract Habitat fragmentation is known to cause population declines but the mechanisms leading to the decline are not fully understood. Fragmentation is likely to lead to changes in predation risk, which may cause behavioral responses with possible population level consequences. It has recently been shown that the awareness of predator presence, resulting in a fear response, strongly affects behavior and physiology of the prey individuals. Costs arising from fear may be as important for the prey population size as the direct killing of prey. We tested how predation risk in the form of scent of a specialist predator, the least weasel (Mustela nivalis nivalis), affects bank vole (Myodes glar…

Predation and resource fluctuations drive eco-evolutionary dynamics of a bacterial community

2012

Predation and temporal resource availability are among the most important factors determining prey community dynamics and composition. Both factors have been shown to affect prey diversity, but less is known about their interactive effects, especially in rapidly evolving prey communities. In a laboratory microcosm experiment, we manipulated the presence of the predatory protozoan Tetrahymena thermophila and the temporal patterns in the availability of resources for a bacterial prey community. We found that both predation and temporal fluctuations in prey resources resulted in a more even prey community, and these factors also interacted so that the effect of predation was only seen in a flu…

Evaluación del índice de pobreza hídrica (WPI) en la cuenca de Borujerd-Dorood (Irán) para reforzar los planes de gestión del territorio

2021

El Índice de Pobreza Hídrica (WPI) se considera, en general, una herramienta simple y clara para evaluar los efectos de factores combinados sobre la escasez de agua y la tensión de los recursos hídricos. En esta investigación, intentamos centrarnos en las problemáticas hídricas en las cabeceras de montaña de la cuenca de Karoon en Irán para analizar el estado de los recursos hídricos. Para este propósito, los datos requeridos se obtuvieron en primer lugar mediante la preparación de un informe de la Autoridad del Agua, la parte Agrícola y la Organización de Agua y Saneamiento del Condado de Borujerd. Luego, se estimó el valor del WPI a escala de subcuenca del río Karoon considerando como rec…

Quantitative Genetics of the Aging of Reproductive Traits in the Houbara Bustard

2015

International audience; Do all traits within an organism age for the same reason? Evolutionary theories of aging share a common assumption: the strength of natural selection declines with age. A corollary is that additive genetic variance should increase with age. However, not all senescent traits display such increases suggesting that other mechanisms may be at play. Using longitudinal data collected from more than 5400 houbara bustards (Chlamydotis undulata) with an exhaustive recorded pedigree, we investigated the genetics of aging in one female reproductive trait (egg production) and three male reproductive traits (courtship display rate, ejaculate size and sperm viability), that displa…

Landscape-scale simulation experiments test Romanian and Swiss management guidelines for mountain pasture-woodland habitat diversity

2016

Distinct guidelines have been proposed in Romania and Switzerland for the management of pasture woodlands that either focused on the regulation of grazing pressure (Romanian production perspective) or overall tree cover (Swiss conservation perspective). However, the landscape structural diversity and the cover of forest-grassland ecotones, which are both crucial for nature conservation value, were not explicitly considered. We aimed to compare the country-specific management guidelines regarding their efficiency for the conservation of the structurally diverse forest-grassland mosaics in the light of recent land-use and climate change. In strategic simulation experiments using the process-b…

2018

Allometric relationships linking species characteristics to body size or mass (scaling) are important in biology. However, studies on the scaling of life history traits in the reptiles (the nonavian Reptilia) are rather scarce, especially for the clades Crocodilia, Testudines, and Rhynchocephalia (single extant species, the tuatara). Previous studies on the scaling of reptilian life history traits indicated that they differ from those seen in the other amniotes (mammals and birds), but so far most comparative studies used small species samples and also not phylogenetically informed analyses. Here, we analyzed the scaling of nine life history traits with adult body mass for crocodiles (n = 2…

Environmental Variability and Semelparity vs. Iteroparity as Life Histories

2002

Research on the evolution of life histories addresses the topic of fitness trade-offs between semelparity (reproducing once in a lifetime) and iteroparity (repeated reproductive bouts per lifetime). Bulmer (1994) derived the relationship v+P(A)<1 (P(A) is the adult survival;vb(S) and b(S) are the offspring numbers for iteroparous and semelparous breeding strategies, respectively), under which a resident semelparous population cannot be invaded by an iteroparous mutant when the underlying population dynamics are stable. We took Bulmer's population dynamics, and added noise in juvenile and adult survival and in offspring numbers. Long-term coexistence of the two strategies is possible in much…

Future Cities. Urban Transformation and Sustainable Development

2016

The complex urban reality, in continuous evolution, are characterized by buildings, facilities, equipment, human capital, social capital and the ability to create sustainable economic development. Today, urban planning is called to respond to the new needs of the community, for this reason it is necessary to avoid the mistakes made in the past and think of a plan to be adapted to the change. All this is possible through the implementation of participatory strategic actions which ensure high levels of quality of life as well as responsible management of land resources. This outlines the concept of sustainable development and resilient cities, forcefully entered in today’s urban paradigm, bec…

A new rationale for not picking low hanging fruits: The separation of ownership and control

2019

Recent attempts at explaining the energy-efficiency gap rely on considerations related to organizational and behavioral/cognitive failures. In this paper, we build on the strategic delegation literature to advance a complementary explanation. It is shown that strategic market interaction may encourage business owners to instill a bias against energy efficiency in managerial compensation contracts. Since managers respond to financial incentives, their decisions will reflect this bias, resulting in lack of investment.

An ecological multi-Level theory of competition for resources used to analyse density-dependence effects in fruit production

2014

International audience; Lescourret and Génard (2003) developed a multi-level theory of competition for resources applied to fruit production, considering that any collection of unit parts (cells or seeds in a fruit, fruits in an infructescence or in a tree...) can form a population and the population is subject to competition, whatever the level of organization. The principles of the theory are that the mass of each unit decreases when the number of units in the population increases and that the total mass of the population increases as the number of units increases until it reaches a maximum, after which it decreases. A three-parameter model based on that theory was used to analyse the lev…