Time filter

Source Type

Abu Dhabi, United Arab Emirates

Frenette-Dussault C.,Universite de Sherbrooke | Shipley B.,Universite de Sherbrooke | Hingrat Y.,RENECO Wildlife Consultants LLC
Functional Ecology

Animal ecology could benefit from a well-defined trait-based framework, mostly applied in plant ecology, to further develop predictions of animal communities under various environmental conditions. We extended the functional approach to a multitrophic system by combining plant and ant traits in relation to environmental conditions to study the relationships between these three components. We sampled plant and ant abundances along an aridity gradient in grazed and ungrazed conditions in the arid steppes of eastern Morocco. We measured five plant functional traits related to water stress and grazing resistance and six ant functional traits related to body size, dispersal and behaviour. We related each component (environment, vegetation and ants) using Mantel partial correlations to uncover the causal structure between components and using a fourth-corner analysis to describe the effects of the environment and vegetation on ant communities. Results indicated that vegetation had a direct effect on ant community composition while the environment only had an indirect effect on ant community composition through vegetation structure. This result was consistent when looking at both the taxonomic and functional composition of communities, but correlations were stronger when based on taxonomic composition. Aridity was the variable most significantly linked with ant functional traits Synthesis. The use of functional traits in animal ecology is relatively new, and an increase in trait-based community ecology studies that include more than one trophic level would be beneficial in identifying trait-based patterns in multitrophic communities. This new approach could become very useful in identifying mechanistic explanations of multitrophic community assembly and making predictions about their evolution under changing environmental conditions. It could also be of practical use in conservation biology in assessing habitat quality. © 2013 The Authors. Functional Ecology © 2013 British Ecological Society. Source

Frenette-Dussault C.,Universite de Sherbrooke | Shipley B.,Universite de Sherbrooke | Leger J.-F.,Emirates Center for Wildlife Propagation | Meziane D.,University Sidi Mohammed Ben Abdellah | Hingrat Y.,RENECO Wildlife Consultants LLC
Journal of Vegetation Science

Questions: (1) How do community-weighted mean (CWM) trait values of 23 functional traits measured on 34 plant species vary along a gradient of aridity under grazed and ungrazed conditions in an arid steppe? (2) How does variation in our CWM trait values differ from those of more mesic grasslands? Location: Eastern Morocco. Methods: We measured relative abundance and functional traits along a short aridity gradient over two consecutive years at five heavily grazed sites, each with an exclosure preventing grazing. We analysed the relationship between aridity, grazing, and the expression of CWM trait values using ordination methods and a fourth-corner analysis. Results: Unconstrained and constrained ordinations identified three distinct suites of temporally consistent functional traits that co-varied with aridity and grazing, and the fourth-corner analysis identified a number of significant but weak trait-environment associations. Grazing selected for short, fast-growing annual species with high SLA, high pastoral value and low seed mass, while aridity selected for species possessing succulent leaves with high δ 13C leaf content, spines, low LDMC and short stature, although the relative importance of precipitation and grazing changed between years. Conclusions: Although distinct from more mesic grasslands, our study sites exhibited patterns of trait correlations that were similar to the worldwide leaf economics spectrum. These correlation patterns represented three groups that were reminiscent of Grime's C-S-R model. Direct ordinations supported this interpretation. Temporal variation in our results was due in part to precipitation fluctuations. Our results also indicated selection for a grazing avoidance strategy under heavy grazing. Integrating plant functional traits in conservation and management of arid ecosystems represents a novel and challenging task to ensure more sustainable use of these lands. © 2011 International Association for Vegetation Science. Source

Monnet A.-C.,French Natural History Museum | Monnet A.-C.,Emirates Center for Wildlife Propagation | Hardouin L.A.,French Natural History Museum | Hardouin L.A.,Emirates Center for Wildlife Propagation | And 4 more authors.

Despite the increasing use of species distribution models for predicting current or future animal distribution, only a few studies have linked the gradient of habitat suitability (HS) to demographic parameters. While such approaches can improve the reliability of models, they can help to better predict the response of species to changes in HS over space and time, as induced by ongoing global change. Here, we tested whether the spatial variation in HS along the individual movement path is related to survival, using extensive tracking data collected from captive-bred individuals translocated to reinforce the wild populations of houbara bustard. We first modelled and mapped the HS from presence data of wild individuals using niche models in a consensus framework. We further analysed survival of released individuals using capture-recapture modelling and its links to HS, as the trend in suitability from the release sites along movements. We found that the survival of released individuals was related to changes in HS along their movements. For instance, individuals which moved to sites of lower HS than their release sites have lower survival probabilities than the others, independently of the HS of the release sites and daily movement rate. Our results provide an empirical support of the relationship between HS and survival, a major fitness component. © 2014 The Authors. Source

Mancini A.,Hurghada Environmental Conservation and Protection Association | Elsadek I.,Boomerang For Earth Conservation | Elsadek I.,Suez Canal University | Madon B.,Boomerang For Earth Conservation | Madon B.,RENECO Wildlife Consultants LLC
Journal of Experimental Marine Biology and Ecology

Estimating population abundance of marine turtles on their feeding grounds is needed to implement effective conservation strategies, but is logistically challenging. In-water monitoring surveys on feeding grounds are costly, time-consuming, stressful to the animals (when capture is required), and typically requires complex analytical skills. Here, we compare two sampling methods to estimate abundance of green turtles on one of their major feeding grounds in the Egyptian Red Sea: a) snorkelling strip transect counts, a rarely used method on marine turtles; and b) capture-mark-recapture (CMR) using photo-identification. The main goals of this research were to: 1) identify the most cost-effective method to estimate in-water marine turtle abundance; and 2) provide the first abundance estimates for green turtles on their feeding grounds in the Red Sea. Both methods produced an average monthly abundance of approximately 30 turtles, with no significant difference between the two methodologies. The strip-transect method presented major logistical advantages, including easy field implementation, simple equipment, and only basic analytical skills. Furthermore, this method provided density estimates that can be used as index for population trends. However, limitations of this method included intensive field effort and potentially altered turtle behaviour due to the presence of the observers. By contrast, photo-identification and CMR models provided valuable information of population demography but required advanced analytical skills, did not provide a measure of density, and could prove challenging in areas where turtles are not acclimated to human presence. Our results suggest that the ease data collection and associated analysis of the strip transect method should be considered when implementing a monitoring program of wildlife to be used for management and conservation purposes. © 2015 Elsevier B.V. Source

Frenette-Dussault C.,Universite de Sherbrooke | Shipley B.,Universite de Sherbrooke | Meziane D.,University Sidi Mohammed Ben Abdellah | Hingrat Y.,RENECO Wildlife Consultants LLC
Journal of Ecology

Global climate change is possibly one of the most important challenges for current and future human populations due to its wide-ranging effects on ecosystems. Global prediction models suggest that in some areas of the world (e.g. Northern Africa, Central America) an increase in aridity might strongly disturb agricultural production and affect food security. To counterbalance these negative effects, reliable predictive models are needed to anticipate ecosystem changes. We tested the ability of the Community Assembly by Trait-based Selection (CATS) model that is based on the principle of maximum entropy and trait-based environmental filtering, to predict actual and future plant community composition in the arid steppes of eastern Morocco. Specifically, we asked whether this model was adequate for predicting actual community composition, based on predicted community-weighted mean (CWM) traits, and what would be the changes in community composition under various scenarios of climate change for the period 2080-2099. The CATS model could predict > 90% of actual community composition if the actual CWM traits were known but only ̃40% if the CWM values were predicted from estimated aridity and grazing values. The predictions of community composition for 2080-2099 suggested that, regardless of the climate change scenario considered, the dominant group in grazed and ungrazed sites would shift from ruderal species to stress-tolerant sub-shrubs, which would constitute up over 80% of total community composition in some cases. Synthesis. Our findings suggest that effects of climate change will strongly modify plant community structure in arid steppes, possibly accentuating the process of desertification, and reducing the pastoral value of the vegetation. Future research efforts should concentrate on the identification of strong trait-environment relationships to improve model predictions. © 2012 The Authors. Journal of Ecology © 2012 British Ecological Society. Source

Discover hidden collaborations