Leader D. Mouillot
Science in general and ecology in particular requires historical baselines to assess the effects of environmental variables and especially those caused by natural or anthropogenic disturbance. For example, how can we assess the impact of humans on a marine ecosystem if we do not know the state of that ecosystem before its anthropisation or the state of an ecosystem with similar environmental conditions but without any human impact? One can legitimately wonder about the composition of fauna and flora encountered by those explorers setting "the first human foot and eye" on certain islands and other isolated lands around the world. What did they find? What was the state of biodiversity like, what was the average size reached by individuals, what was their habitat like before humans pushed them to the edges of their territory? Naturalist reports produced prior to the 20th century are unfortunately limited in number and contain little detail, making it impossible to establish a baseline for assessing the degradation of our current ecosystems).
However, these totally pristine species assemblages and all their components (diversity, structure, abundance, etc.) constitute not only absolute reference states for assessing human impact on biotopes and biotic communities but also a target that could potentially be reached within the increasingly large number of protected areas around the world. For most ecosystems, these reference states certainly no longer exist (all upwelling zones favourable to fishing have been exploited for example) and the baseline is often inferred from fossil data. This is the background to our project which will redefine the reference state of coral systems in different Pacific countries by sampling the last pristine sites in order to obtain a baseline that can be used to assess not only anthropogenic impact but also protective measures such as the introduction of marine reserves.