Geology topics
Publications and source records attributed to Michel Loreau.
The rate and extent of global biodiversity change is surpassing our ability to measure, monitor and forecast trends. We propose an interconnected worldwide system of observation networks — a global biodiversity observing system (GBiOS) — to coordinate monitoring worldwide and inform action to reach international biodiversity targets.
Despite substantial progress in understanding global biodiversity loss, major taxonomic and geographic knowledge gaps remain. Decision makers often rely on expert judgement to fill knowledge gaps, but are rarely able to engage with sufficiently large and diverse groups of specialists. To improve understanding of the perspectives of thousands of biodiversity experts worldwide, we conducted a survey and asked experts to focus on the taxa and freshwater, terrestrial, or marine ecosystem with which they are most familiar. We found several points of overwhelming consensus (for instance, multiple drivers of biodiversity loss interact synergistically) and important demographic and geographic differences in specialists’ perspectives and estimates. Experts from groups that are underrepresented in biodiversity science, including women and those from the Global South, recommended different priorities for conservation solutions, with less emphasis on acquiring new protected areas, and provided higher estimates of biodiversity loss and its impacts. This may in part be because they disproportionately study the most highly threatened taxa and habitats.
In a recent paper, Schoolmaster, Zirbel, and Cronin (SZC) (2020 ) claim “Formal causal analysis show[s] that biodiversity–ecosystem function (BEF) correlations are non-causal associations.” If this conclusion is accepted as true, it suggests a reconsideration of much of our current understanding of how biodiversity relates to the functioning of ecosystems. On the surface, it is easy to spot clear signs of something problematic with SZC’s presentation. They claim, for example, that (1) species richness is incapable of having a causal effect on ecosystem functioning on theoretical grounds, and (2) that trait diversity cannot be causally influenced by species diversity. These remarkable claims are counter to existing thought and evidence. We point to logical errors that lead them to a misapply causal analysis and produce erroneous conclusions.
As biodiversity is declining at an unprecedented rate, an important current scientific challenge is to understand and predict the consequences of biodiversity loss. Here, we develop a theory that predicts the temporal variability of community biomass from the properties of individual component species in monoculture. Our theory shows that biodiversity stabilises ecosystems through three main mechanisms: (1) asynchrony in species’ responses to environmental fluctuations, (2) reduced demographic stochasticity due to overyielding in species mixtures and (3) reduced observation error (including spatial and sampling variability). Parameterised with empirical data from four long-term grassland biodiversity experiments, our prediction explained 22–75% of the observed variability, and captured much of the effect of species richness. Richness stabilised communities mainly by increasing community biomass and reducing the strength of demographic stochasticity. Our approach calls for a re-evaluation of the mechanisms explaining the effects of biodiversity on ecosystem stability.
The most unique feature of Earth is the existence of life, and the most extraordinary feature of life is its diversity. Approximately 9 million types of plants, animals, protists and fungi inhabit the Earth. So, too, do 7 billion people. Two decades ago, at the first Earth Summit, the vast majority of the world's nations declared that human actions were dismantling the Earth's ecosystems, eliminating genes, species and biological traits at an alarming rate. This observation led to the question of how such loss of biological diversity will alter the functioning of ecosystems and their ability to provide society with the goods and services needed to prosper.
This chapter considers the context in which manipulative parasites could have noticeable ecological effects. By this, we mean that a manipulation of a host that benefits a parasite can also indirectly affect other non-hosts in the system, sometimes in dramatic fashion. Such ecosystem-level changes could occur for manipulative parasites that have a strong effect on their host, a high rate of infection, and infect hosts that play important roles in the ecosystem. With a series of examples from the literature, the chapter describes how manipulative parasites can sometimes have strong indirect ecological effects. Still, little is known about how often these effects occur in nature.