Search results for "Ecological Network"
showing 10 items of 40 documents
Fragmentation des habitats et interactions hôtes-parasites
2021
Habitat fragmentation is one of the main threats to global biodiversity and despite an abundant literature on the impact of fragmentation on species abundance and diversity, the consequences of this global change in terms of ecological and evolutionary processes remain poorly understood. Beyond their direct contribution to biodiversity, as species-rich category of organisms, parasites could be involved in biodiversity change as key actors of ecological and evolutionary processes. The present work aims to understand the effect of forest fragmentation on host-parasite interactions. It is based on a large sampling carried out in the Lesser Antilles and in French Guiana, and allowing the obtent…
The starry sky, a territorial commons?
2021
International audience; Flagstaff, Arizona, United States, April 15, 1958: the city council adopts the ordinance n°440 which aims at “preventing a rapid deterioration of the visibility of the starry sky”. This regulation results from the mobilization of the Lowell Observatory astronomers against certain public lighting devices. Through this political act, the elected officials place their city at the epicenter of an emergent international movement: the ‘Dark-sky movement’. The first replica of this movement is felt in 1972 in Tucson, Arizona. From a discomfort perceived by astronomers from the Lowell and Kitt Peak observatories, the idea of ‘light pollution’ emerges and begins to spread thr…
'Dark Ecological Network': strategically tackling light pollution for biodiversity and people
2021
Night-time light pollution from artificial sources can disrupt biological processes and fragment habitats. This study presents a new concept foraddressing the problem: a 'dark ecological network'. Its development involves mapping a new system of connected functional zones and corridors where dark can be preserved to help birds, bats and other taxa, and gives people the chance to experience starry skies.
Un Parco nella Sicilia più nascosta
2021
Le aree interne della Sicilia sono caratterizzate, oltre che dalle tipiche crisi delle aree marginali, da altri fattori peculiari quali una costante arretratezza tecnologica e uno disfattismo di gattopardesca memoria. Esse sono anche però il luogo ove lo sviluppo locale potrebbe riportare i suoi migliori esiti, trasformandole da luoghi del sottosviluppo in luoghi di rinnovata e viva identità. Ciò in virtù dalla immensa potenzialità che luoghi naturali come i Parchi possiedono intrinsecamente per avviare uno sviluppo sostenibile che riesca a mantenere le componenti identitarie e paesaggistiche di un luogo e al contempo risollevarne le sorti. Il caso studio, ivi presentato, riguarda il Parco …
Limited effects of size-selective harvesting and harvesting-induced life-history changes on the temporal variability of biomass dynamics in complex f…
2023
Harvesting has been implicated in destabilizing the abundances of exploited populations. Because selective harvesting often targets large individuals, some studies have proposed that exploited populations often experience demographic shifts toward younger, smaller individuals and become more sensitive to environmental fluctuations. The theory of consumer–resource dynamics has been applied to address the impacts of harvesting in simple modular food webs, but harvested populations are embedded in a complex food web in nature. In addition, exploited populations have been shown to undergo trait evolution or phenotypic changes toward early maturation at smaller sizes. Using an empirically derive…
Urban Services to Ecosystems: An Introduction
2021
Green infrastructure is a structural system of naturally developed human societies, capable of preserving and ensuring as much space as possible to the local biodiversity. For this reason, green infrastructure shall be planned and designed so that the urban built environment is in harmony with the surrounding biotic communities. The challenge is to sustain nature-based solutions in order to improve citizens’ awareness towards natural and semi-natural ecosystems while providing our society with a more liveable, healthier, safer and fairer environment. This book puts an emphasis on the services the city can offer to nature, thanks to a multidisciplinary approach involving scientists and pract…
Biotic homogenisation in bird communities leads to large-scale changes in species associations
2020
AbstractAimThe impact of global change on biodiversity is commonly assessed in terms of changes in species distributions, community richness and community composition. Whether and how much associations between species, i.e. the degree of correlation in their spatial co-occurrence, are also changing is much less documented and mostly limited to local studies of ecological networks. In this study, we quantify changes in large-scale patterns of species associations in bird communities in relation to changes in species composition.LocationFrance.Time period2001-2017.Major taxa studiedCommon breeding birds.MethodsWe use network approaches to build three community-aggregated indices reflecting co…
Comparison of methods to model species habitat networks for decision-making in nature conservation : the case of the wildcat in southern Belgium
2020
Facing the loss of biodiversity caused by landscape fragmentation, implementation of ecological networks to connect habitats is an important biodiversity conservation issue. It is necessary to develop easily reproducible methods to identify and prioritize actions to maintain or restore ecological corridors. To date, several competing methods are used with recurrent debate on which is best and if expert-based approaches can replace data-driven models. We compared three methods: knowledge-driven (expert based), data-driven (based on species distribution model), and a mixed approach. We quantified their differences in habitat and corridor mapping, and prioritizations of landscape elements in t…
Self-regulation mechanism of an ecosystem in a non-Gaussian fluctuation regime
1996
We study a dynamical model for an ecological network of many interacting species. We consider a Malthus-Verhulst type of self-regulation mechanism. In the framework of the mean field theory we study the nonlinear relaxation in three different cases: (a) towards the equilibrium state, (b) towards the absorbing barrier, (c) at the critical point. We obtain asymptotic behavior in all different cases for the time average of the process. The dynamical behavior of the system, in the limit of infinitely many interacting species, is investigated in the stability and instability conditions and theoretical results are compared with numerical simulations. \textcopyright{} 1996 The American Physical So…
I TETTI VERDI DI TIPO ESTENSIVO: BIODIVERSITÀ AD ALTA QUOTA
2016
Le città sono state paragonate da Odum a degli organismi eterotrofi che basano la loro crescita ed espansione sull’uso indiscriminato di risorse e sono causa di perdita irreversibile e frammentazione degli habitat naturali. I tetti verdi rappresentano uno strumento essenziale di mitigazione e compensazione ambientale all’interno del tessuto urbano dove, l’alta densità edilizia e l’elevato disturbo antropico concedono poco spazio alle dinamiche naturali. In particolare, i tetti verdi per la biodiversità caratterizzati da mosaici di micro-habitat diversi e contigui tra loro, possano ospitare specie con caratteristiche morfo-funzionali diverse. L’approccio noto come habitat template, consiste …