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D'Agata, S., Mouillot, D., Kulbicki, M., Andrefouet, S., Bellwood, D. R., Cinner, J. E., et al. (2014). Human-Mediated Loss of Phylogenetic and Functional Diversity in Coral Reef Fishes. Current Biology, 24(5), 555–560.
Résumé: Beyond the loss of species richness [1-3], human activities may also deplete the breadth of evolutionary history (phylogenetic diversity) and the diversity of roles (functional diversity) carried out by species within communities, two overlooked components of biodiversity. Both are, however, essential to sustain ecosystem functioning and the associated provision of ecosystem services, particularly under fluctuating environmental conditions [1-7]. We quantified the effect of human activities on the taxonomic, phylogenetic, and functional diversity of fish communities in coral reefs, while teasing apart the influence of biogeography and habitat along a gradient of human pressure across the Pacific Ocean. We detected nonlinear relationships with significant breaking points in the impact of human population density on phylogenetic and functional diversity of parrot-fishes, at 25 and 15 inhabitants/km(2), respectively, while parrot-fish species richness decreased linearly along the same population gradient. Over the whole range, species richness decreased by 11.7%, while phylogenetic and functional diversity dropped by 35.8% and 46.6%, respectively. Our results call for caution when using species richness as a benchmark for measuring the status of ecosystems since it appears to be less responsive to variation in human population densities than its phylogenetic and functional counterparts, potentially imperiling the functioning of coral reef ecosystems.
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Dobrovolski, R., Loyola, R. D., Guilhaumon, F., Gouveia, S. F., & Diniz, J. A. F. (2013). Global agricultural expansion and carnivore conservation biogeography. Biol. Conserv., 165, 162–170.
Résumé: Global conservation prioritization must address conflicting land uses. We tested for spatial congruence between agricultural expansion in the 21st century and priority areas for carnivore conservation worldwide. We evaluated how including agricultural expansion data in conservation planning reduces such congruence and estimated the consequences of such an approach for the performance of resulting priority area networks. We investigated the correlation between projections of agricultural expansion and the solutions of global spatial prioritizations for carnivore conservation through the implementation of different goals: (1) purely maximizing species representation and (2) representing species while avoiding sites under high pressure for agriculture expansion. We also evaluated the performance of conservation solutions based on species' representation and their spatial congruence with established global prioritization schemes. Priority areas for carnivore conservation were spatially correlated with future agricultural distribution and were more similar to global conservation schemes with high vulnerability. Incorporating future agricultural expansion in the site selection process substantially reduced spatial correlation with agriculture, resulting in a spatial solution more similar to global conservation schemes with low vulnerability. Accounting for agricultural expansion resulted in a lower representation of species, as the average proportion of the range represented reduced from 58% to 32%. We propose that priorities for carnivore conservation could be integrated into a strategy that concentrates different conservation actions towards areas where they are likely to be more effective regarding agricultural expansion. (C) 2013 Elsevier Ltd. All rights reserved.
Mots-Clés: Agriculture; Global biodiversity conservation priorities; Image; Mammal; Spatial prioritization; Zonation; biodiversity; biodiversity conservation; conservation; conserving; extinction risk; hotspots; human-population density; integrating economic costs; land-use; mammal conservation; prioritization schemes; protected areas
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Fournier, T., Fevre, J., Carcaillet, F., & Carcaillet, C. (2020). For a few years more: reductions in plant diversity 70 years after the last fire in Mediterranean forests. Plant Ecol., .
Résumé: Changes in community diversity and dynamics after fires in Mediterranean ecosystems are rarely investigated more than a few years after the fire even though pronounced changes can be expected in the longer term due to substitution of canopy species. Pinus halepensis is strongly promoted by wildfire and should therefore be gradually substituted by Quercus species as the time since the last fire increases. We hypothesized that this tree substitution would cause changes in understorey plant diversity by changing resource availability and the abundance and properties of woody debris, leading to changes in biogeochemical processes. To test this hypothesis, we investigated the effect of the time since last fire on vascular plant composition and diversity by studying a 130 years post-fire chronosequence in mixed Mediterranean forests. The canopy composition went from domination by Pinus halepensis to domination by Quercus 70 years after the most recent fire. This transformation was associated with a change in the understorey involving a rarefaction of species present during the first decades after the fire. The plant density or cover also changed with time since the last fire, indicating a succession driven by species rarefaction rather than substitution. The mean richness and Shannon diversity per quadrat were highest shortly after the fire, and were significantly lower 70 or more years after the last fire. Fires are important for supporting highly diversified fire-dependent plant communities, and total plant richness decreases monotonically over time after fires, suggesting that fire suppression may reduce diversity in Mediterranean forests.
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Mouton, T. L., Matheson, F. E., Stephenson, F., Champion, P. D., Wadhwa, S., Hamer, M. P., et al. (2019). Environmental filtering of native and non-native stream macrophyte assemblages by habitat disturbances in an agricultural landscape. Sci. Total Environ., 659, 1370–1381.
Résumé: Understanding how inter-specific variation in functional traits affects native and non-native species responses to stream disturbances, is necessary to inform management strategies, providing tools for biomonitoring, conservation and restoration. This study used a functional trait approach to characterise the responses of macrophyte assemblages to reach-scale disturbances (measured by lack of riparian shading, altered hydromorphology and eutrophication), from 97 wadeable stream sites in an agriculturally impacted region of New Zealand. To determine whether macrophyte assemblages differed due to disturbances, we examined multidimensional assemblage functional structure in relation to eleven functional traits and further related two functional diversity indices (entropy and originality) to disturbances. Macrophyte assemblages showed distinct patterns in response to disturbances, with riparian shading and hydromorphological conditions being the strongest variables shaping macrophyte functional structure. In the multidimensional space, most of the non-native species were associatedwith disturbed conditions. These species had traits allowing faster colonisation rates (higher number of reproductive organs and larger root-rhizome system) and superior competitive abilities for resources (tall and dense canopy, heterophylly and greater preferences for light and nitrogen). In addition, lack of riparian shading increased the abundance of functionally distinct species (i.e. entropy), and eutrophication resulted in the growth of functionally unique species (i.e. originality). We demonstrated that stream reach-scale habitat disturbances were associated to a dominance of more productive species, equating to a greater abundance of non-native species. This, can result in a displacement of native species, habitat alterations, and changes to higher trophic level assemblages. Our results suggests that reachscale management efforts such as the conservation and restoration of riparian vegetation that provides substantial shading and hydromorphologically diverse in-stream habitat, would have beneficial direct and indirect effects on ecosystem functioning, and contribute to the mitigation of land-use impacts. (C) 2018 Published by Elsevier B.V.
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Seddon, N., Mace, G. M., Naeem, S., Tobias, J. A., Pigot, A. L., Cavanagh, R., et al. (2016). Biodiversity in the Anthropocene: prospects and policy. Proc. R. Soc. B-Biol. Sci., 283(1844), 20162094.
Résumé: Meeting the ever-increasing needs of the Earth's human population without excessively reducing biological diversity is one of the greatest challenges facing humanity, suggesting that newapproaches to biodiversity conservation are required. One idea rapidly gaining momentum-as well as opposition-is to incorporate the values of biodiversity into decision-making using economic methods. Here, we develop several lines of argument for how biodiversity might be valued, building on recent developments in natural science, economics and science-policy processes. Then we provide a synoptic guide to the papers in this special feature, summarizing recent research advances relevant to biodiversity valuation and management. Current evidence suggests that more biodiverse systems have greater stability and resilience, and that by maximizing key components of biodiversity we maximize an ecosystem's long-term value. Moreover, many services and values arising from biodiversity are interdependent, and often poorly captured by standard economic models. We conclude that economic valuation approaches to biodiversity conservation should (i) account for interdependency and (ii) complement rather than replace traditional approaches. To identify possible solutions, we present a framework for understanding the foundational role of hard-to-quantify ` biodiversity services' in sustaining the value of ecosystems to humanity, and then use this framework to highlight new directions for pure and applied research. In most cases, clarifying the links between biodiversity and ecosystem services, and developing effective policy and practice for managing biodiversity, will require a genuinely interdisciplinary approach.
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