Victor Cazalis

Researcher in Conservation Biology

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Research interests

My main motivation in doing research holds in the word “Conservation”. I want my research to help, directly or indirectly, conserving species and nature. This applied will is combined with a strong appetence for large and global spatial scales. Indeed, I like to think about the global impact that humans have on biodiversity and about the solutions that we have in our hands to mitigate biodiversity loss at global scale. Studying conservation effectiveness and participating in the development of indexes to track biodiversity loss and conservation effects are thus central in my research interests. I also feel drawn to social sciences when they help understanding what makes conservation actions more effective and I hope to develop this in the future.

Research projects

IUCN Red List support

The IUCN Red List of Threatened Species is absolutely central in biodiversity conservation, but limited resources constrain its growth, update and consistency. The objective of the working group my current post-doc fits in is to help develop modelling tools to support assessments and to provide them to Red List assessors through an online platform. This project started with a synthesis of existing studies and tools, developed in a perspective paper (Cazalis et al. 2022, TREE), and I am now working on two analytic studies, one focusing on predicting data sufficient species, the other one trying to measure AOO and trends in AOO.

Protected area effectiveness

During my PhD I worked on evaluating the effectiveness of the main tool used in conservation and that is central in international conservation agreements such as the Convention on Biological Diversity: protected areas. The term “protected area effectiveness” in used in many ways as it incapsulates multiple complementary facets that together explains how protected areas enable the long term conservation of nature (Rodrigues and Cazalis 2020, Nat.Comms).

The facet most of my PhD focused on is the local effectiveness of protected areas: do they make a difference locally for species. We showed that protected areas do not often affect the local richness of assemblages but that they favour more typical assemblages and thus mitigate biotic homogeneisation. This was the case in a study using a standard dataset (the North American Breeding Bird Survey; Cazalis et al. 2021, Peer Community Journal), as well as a study using eBird data from eight tropical forest biodiversity hotspots that showed that protected areas do not affect overall species richness but that they do favour forest-dependent species, endemic species, and threatened species by mitigating both forest loss and forest degradation (Cazalis et al. 2020, Nat.Comms). Wondering if protected areas’ effects vary with the context surrounding them, we show that urban protected areas in Latin America (e.g., National Park of Tijuca) keep an important diversity within their boundaries but that this diversity is reduced compared with non-urban protected areas (lower richness and abundance, lower proportion of forest-dependent species, of narrow-ranged species and of threatened species) except for exotic species that are more abundant in protected areas that are urban (Cazalis et al. In prep.). In addition, I collaborated in a study showing that Ramsar (protected areas focusing on wetlands) across the Mediterranean host most waterbirds but have low impact on species trends suggesting a poor local effectiveness (Gaget et al. 2020, Bio.Cons.).

In another project we explored the effectiveness of the current protected area network in the Americas at providing intact habitats to species that are the most sensitive to human pressure. We show that ecoregions with high proportion of high-sensitivity species (mainly in the Andes and Central America) are not more covered by intact protected areas and thus that many high-sensitivity species cannot be effectively conserved by protected areas as their distribution does not intersect (or negligibly) with intact protected areas (Cazalis et al. 2021, Ecology Letters).

As a side project to my PhD, I led an interdisciplinary study in Conservation Psychology in which we show that in France, people living close to natural park tend to adopt more pro-environmental behaviours (i.e., voting for green parties, supporting conservation NGOs, participating in citizen science projects), suggesting that protected areas may play a role in conservng human connection with nature (Cazalis and Prévot 2019, Bio.Cons.)

Several of the above-mentioned facets of protected area effectiveness are part of the Aichi Target 11, related to protected areas, that almost all governments have promised to reach by 2020. In a review of the progress towards this target, we show that none of the subojectives of this target have been met and that governments have underinvested in protected areas in the last decade (Maxwell et al. 2020, Nature) and we call for the formulation of outcome-based objectives for the post-2020 biodiversity framework.

Other projects

In an ongoing project (Cazalis 2022, PNAS), I investigate the exact effect of human footprint on overall species richness and on assemblage composition and suggest the existence of a two-phases relationship (first assemblage transformation resulting in a low increase species richness, followed by a decline in species richness when pressure becomes too important) and I suggest a unifying framework on the different trajectories of species richness response to human pressure.

Following the article with on human pro-environmental behaviours, I led a review of our current knowledge in trends in human experience of nature, in order to understand how human connection with nature has evolved in the past decades and question the “extinction of experience” (Cazalis et al. Accepted in Frontiers in Ecology and the Environment).

During my Masters, I worked on a theoretical model exploring the balance between human demography, land-use and ecosystem services (Cazalis et al. 2018, Sci.Tot.Env)

I have been also involved, providing statistical support, in a review of the global tracking effort on seabirds, in which we identify species that have never or rarely been tracked and for which the knowledge, on migration and wintering behaviours, is lacking (Bernard et al. 2021, Cons.Lett.).