Historical evidence for nature disconnection in a 70-year time series of Disney animated films

The assumed ongoing disconnection between humans and nature in Western societies represents a profoundly challenging conservation issue. Here, we demonstrate one manifestation of this nature disconnection, via an examination of the representation of natural settings in a 70-year time series of Disney animated films. We found that natural settings are increasingly less present as a representation of outdoor environments in these films. Moreover, these drawn natural settings tend to be more and more human controlled and are less and less complex in terms of the biodiversity they depict. These results demonstrate the increasing nature disconnection of the filmmaking teams, which we consider as a proxy of the Western relation to nature. Additionally, because nature experience of children is partly based on movies, the depleted representation of biodiversity in outdoor environments of Disney films may amplify the current disconnection from nature for children. This reduction in exposure to nature may hinder the implementation of biodiversity conservation measures.

Exotic species, experienced, and idealized nature

This paper is an answer to the Caplat and Coutts forum about our previous paper "The need for flexibility in conservation practices: exotic species as an example". We precise here why we proposed to consider exotic species as well as indigenous species in the reconnection framework in human-modified environments. One argument is that consistent and understandable arguments must be used in the communication from scientists to the public, in order not to decrease the gap between science and society.

Pigeons discriminate between human feeders

Considered as plague in many cities, pigeons in urban areas live close to human activities and exploit this proximity to find food which is often directly delivered by people. In this study, we explored the capacity of feral pigeons to take advantage of this human-based food resource and discriminate between friendly and hostile people. Our study was conducted in an urban park. Pigeons were fed by two experimenters of approximately the same age and skin colour but wearing coats of different colours. During the training sessions, the two human feeders displayed different attitudes: one of the feeders was neutral and the second was hostile and chased away the pigeons. During the two test phases subsequent to the training phase, both feeders became neutral. Two experiments were conducted, one with one male and one female feeder and the second with two female feeders. In both experiments, the pigeons learned to quickly (six to nine sessions) discriminate between the feeders and maintained this discrimination during the test phases. The pigeons avoided the hostile feeder even when the two feeders exchanged their coats, suggesting that they used stable individual characteristics to differentiate between the experimenter feeders. Thus, pigeons are able to learn quickly from their interactions with human feeders and use this knowledge to maximize the profitability of the urban environment. This study provides the first experimental evidence in feral pigeons for this level of human discrimination.

The need for flexibility in conservation practices: exotic species as an example

To garner support for biodiversity from the World's human population, conservation biologists need an open-minded, integrated conservation strategy. We suggest that this strategy should include efforts to (1) preserve existing high quality, diverse ecosystems, (2) remediate impaired systems, (3) balance the needs of people and ecological resources, and (4) engender appreciation of nature and its services. We refer to these four key tenets as reservation, restoration, reconciliation, and reconnection. We illustrate these concepts by presenting the debate surrounding the management of exotic species from an unusual perspective, the benefits of exotic species. By this example we hope to encourage an integrated approach to conservation in which management strategies can be flexible, adjusting to society's needs and the overall goals of conservation.

Reproduction management affects breeding ecology and reproduction costs in feral urban Pigeons (Columba livia)

Reproduction management of natural popsulations can have long-term consequences that have to be examined to avoid unwanted side effects. Management policies of urban Pigeons ( Columba livia Gmelin, 1789) include the set up of public Pigeon houses that aim at limiting hatching rate by egg removal. However, long-term consequences of this management method on the ecology of this species are still unknown. In this study we examined how egg removal affected egg-laying cycles of Pigeons by using a powerful method of time-series analysis, the wavelet method. We compared egg-laying cycles in Pigeon houses exposed to different management treatments and found that egg-laying cycles were shorter (4 weeks) in Pigeon houses with egg removal compared with control Pigeon houses without egg removal (11 weeks), suggesting that Pigeons respond to egg-removal pressure by multiplying reproduction attempts. Furthermore, we found that egg quality, an important index of female condition, was negatively affected by egg removal. This result suggests that the observed increase of egg production can lead to an increase of reproductive physiological costs and to a decrease of female condition. This study raises issues about potential consequences of such a management procedure on parasite resistance and health status of urban bird populations.

Varying hydric conditions during incubation influence egg water exchange and hatchling phenotype in the red-eared slider turtle

Environmental conditions within the nest, notably temperature and moisture of substrate, exert a powerful influence during embryogenesis in oviparous reptiles. The influence of fluctuating nest temperatures has been experimentally examined in different reptile species; however, similar experiments using moisture as the key variable are lacking. In this article, we examine the effect of various substrate moisture regimes during incubation on different traits (egg mass, incubation length, and hatchling mass) in a chelonian species with flexible-shelled eggs, the red-eared slider turtle (Trachemys scripta elegans). Our results show that the rate of water uptake by the eggs was higher in wet than in dry substrate and varied across development. More important, during the first third of development, the egg mass changes were relatively independent of the soil moisture level; they became very sensitive to moisture levels during the other two-thirds. Moreover, hydric conditions exerted a strong influence on the eggs' long-term sensitivity to the moisture of the substrate. Even short-term episodes of high or low levels of moisture modified permanently their water sensitivity, notably through modification of eggshell shape and volume, and in turn entailed significant effects on hatchling mass (and hence offspring quality). Such complex influences of fluctuating moisture levels at various incubation stages on hatchling phenotype better reflect the natural situation, compared to experiments based on stable, albeit different, moisture levels.

Pets and invasion risks: is the Slider turtle strictly carnivorous?

Abstract

According to the International Union for Conservation of Nature (IUCN), invasive species are one of the most important causes of biodiversity decline at a global scale. The impact of introduced species on local ecosystems is thus important to evaluate. Pet voluntary introductions are made by private people and usually concern only one or two individuals per occasion. However, the number of release occasions is as numerous as the number of pet owners that don't want to keep their pet anymore and then decide to "release" it. Hatchling red-eared slider turtles (Trachemys scripta elegans) have been massively exported from the United States to European (until 1997) and Asian countries to be sold as pets. Many owners, ignoring the potential consequences of their act, have released their grown up turtle in natural freshwater ecosystems. As a consequence, feral adult turtles have been detected all over France. In this paper, we provide information that contradicts public opinion that introduced slider turtle is strictly carnivorous. By analysing the diet of feral adult turtles, we found that adult slider turtles are omnivorous, as in their natural areas.

Trade-off between current reproductive effort and delay to next reproduction in the leatherback sea turtle

The trade-off between current and future reproduction plays an important role in demographic analyses. This can be revealed by the relationship between the number of years without reproduction and reproductive investment within a reproductive year. However, estimating both the duration between two successive breeding season and reproductive effort is often limited by variable recapture or resighting effort. Moreover, a supplementary difficulty is raised when nonbreeder individuals are not present sampling breeding grounds, and are therefore unobservable. We used capture-recapture (CR) models to investigate intermittent breeding and reproductive effort to test a putative physiological trade-off in a long-lived species with intermittent breeding, the leatherback sea turtle. We used CR data collected on breeding females on Awa:la-Ya:lima:po beach (French Guiana, South America) from 1995 to 2002. By adding specific constraints in multistate (MS) CR models incorporating several nonobservable states, we modelled the breeding cycle in leatherbacks and then estimated the reproductive effort according to the number of years elapsed since the last nesting season. Using this MS CR framework, the mean survival rate was estimated to 0.91 and the average resighting probability to 0.58 (ranged from 0.30 to 0.99). The breeding cycle was found to be limited to 3 years. These results therefore suggested that animals whose observed breeding intervals are greater than 3 years were most likely animals that escaped detection during their previous nesting season(s). CR data collected in 2001 and 2002 allowed us to compare the individual reproductive effort between females that skipped one breeding season and females that skipped two breeding seasons. These inferences led us to conclude that a trade-off between current and future reproduction exists in leatherbacks nesting in French Guiana, likely linked to the resource provisioning required to invest in reproduction.

Evidence for birth-site tenacity in breeding Common Black-headed Gulls, Larus ridibundus

We show that in a large colony of Common Black-headed Gulls (Larus ridibundus) in an unstable aquatic habitat, adults that return to their natal colony tend to breed in close proximity to their natal site. We discuss this finding in relation to potential benefits from colonial nesting.