Camille Leclerc

Climate change, sea-level rise, and conservation: keeping island biodiversity afloat.

Island conservation programs have been spectacularly successful over the past five decades, yet they generally do not account for impacts of climate change. Here, we argue that the full spectrum of climate change, especially sea-level rise and loss of suitable climatic conditions, should be rapidly integrated into island biodiversity research and management.

Skin-bacteria communication: Involvement of the neurohormone Calcitonin Gene Related Peptide (CGRP) in the regulation of Staphylococcus epidermidis virulence.

Staphylococci can sense Substance P (SP) in skin, but this molecule is generally released by nerve terminals along with another neuropeptide, Calcitonin Gene Related Peptide (CGRP). In this study, we investigated the effects of αCGRP on Staphylococci. CGRP induced a strong stimulation of Staphylococcus epidermidis virulence with a low threshold (<10−12 M) whereas Staphylococcus aureus was insensitive to CGRP. We observed that CGRP-treated S. epidermidis induced interleukin 8 release by keratinocytes. This effect was associated with an increase in cathelicidin LL37 secretion. S. epidermidis displayed no change in virulence factors secretion but showed marked differences in surface properties. After exposure to CGRP, the adherence of S. epidermidis to keratinocytes increased, whereas its internalization and biofilm formation activity were reduced. These effects were correlated with an increase in surface hydrophobicity. The DnaK chaperone was identified as the S. epidermidis CGRP-binding protein. We further showed that the effects of CGRP were blocked by gadolinium chloride (GdCl3), an inhibitor of MscL mechanosensitive channels. In addition, GdCl3 inhibited the membrane translocation of EfTu, the Substance P sensor. This work reveals that through interaction with specific sensors S. epidermidis integrates different skin signals and consequently adapts its virulence.

Combined impacts of global changes on biodiversity across the USA.

Most studies of the effects of global changes on biodiversity focus on a single threat, but multiple threats lead to species extinction. We lack spatially explicit assessments of the intensity of multiple threats and their impacts on biodiversity. Here, we used a novel metric of cumulative threats and impacts to assess the consequences of multiple threats on 196 endemic species across the USA. We predict that large areas with high cumulative impact scores for amphibians, birds, mammals, and reptiles will be concentrated in the eastern part of the USA by the 2050 s and 2080 s. These high cumulative impact values are due mainly to the presence of invasive species, climate change, cropland and pasture areas; additionally, a significant proportion of endemic species are vulnerable to some of these threats where they occur. This analysis provides a useful means of identifying where conservation measures and monitoring programs that should consider multiple threats should be implemented in the future.

Vulnerability to climate change and sea-level rise of the 35th biodiversity hotspot, the Forests of East Australia

There is an urgent need to understand how climate change, including sea-level rise, is likely to threaten biodiversity and cause secondary effects, such as agro-ecosystem alteration and human displacement. The consequences of climate change, and the resulting sea-level rise within the Forests of East Australia biodiversity hotspot, were modelled and assessed for the 2070–2099 period. Climate change effects were predicted to affect c . 100000 km 2 , and a rise in sea level an area of 860 km 2 ; this could potentially lead to the displacement of 20600 inhabitants. The two threats were projected to mainly affect natural and agricultural areas. The greatest conservation benefits would be obtained by either maintaining or increasing the conservation status of areas in the northern (Wet Tropics) or southern (Sydney Basin) extremities of the hotspot, as they constitute about half of the area predicted to be affected by climate change, and both areas harbour high species richness. Increasing the connectivity of protected areas for Wet Tropics and Sydney Basin species to enable them to move into new habitat areas is also important. This study provides a basis for future research on the effects on local biodiversity and agriculture.

Adapting island conservation to climate change. Response to Andrefouet et al.

In a recent Forum article [1] we argued that conservation on islands should better incorporate climate change in management prioritization schemes. Most species at risk of extinction are threatened by multiple factors [2] including habitat loss, biological invasions, pollution, overexploitation, and climate change. In particular, biological invasions are currently the greatest cause of insular biodiversity decline [3], but climate change and sea-level rise are likely to become more significant threats in the future [4].

Overcoming extinction: understanding processes of recovery of the Tibetan antelope

Since the middle of the 20th century, the Tibetan antelope (Pantholops hodgsonii) has been poached for its wool to make luxury shawls, shahtoosh. This direct overexploitation caused a drastic decline in their population, with a loss of more than 90% compared to the baseline population a few decades ago. Assuming this is an anthropogenic Allee effect (AAE), human attraction for rarity can drive rare species to extinction, which could explain the increasing rates of antelope harvests, paralleling the escalating prices of shahtoosh as the species got rarer. Since 1999, international concern led to conservation actions and the population soon started increasing. This unique situation allowed the presence of an AAE in Tibetan antelope to be tested, as well as an assessment of the potential effects of conservation actions in the presence of this process. We developed a theoretical discrete-time population dynamics model and examined effects of variation in shahtoosh prices. Furthermore, we tested the effects of major conservation actions into our models assessing their relative contribution to population recovery. During the exploitation phase, we found some evidence supporting the presence of an AAE compared to non-AAE models when hunting ceased at antelope population sizes below 10% of the initial population size. Regarding the conservation phase, our results suggested that poacher numbers reduction had the most likely positive impact on Tibetan antelope population dynamics. As many other species are similarly declining and/or close to extinction, our results suggest that adequate conservation actions could counter the most dramatic declines, even when populations have entered an extinction vortex.

Insular threat associations within taxa worldwide

The global loss of biodiversity can be attributed to numerous threats. While pioneer studies have investigated their relative importance, the majority of those studies are restricted to specific geographic regions and/or taxonomic groups and only consider a small subset of threats, generally in isolation despite their frequent interaction. Here, we investigated 11 major threats responsible for species decline on islands worldwide. We applied an innovative method of network analyses to disentangle the associations of multiple threats on vertebrates, invertebrates, and plants in 15 insular regions. Biological invasions, wildlife exploitation, and cultivation, either alone or in association, were found to be the three most important drivers of species extinction and decline on islands. Specifically, wildlife exploitation and cultivation are largely associated with the decline of threatened plants and terrestrial vertebrates, whereas biological invasions mostly threaten invertebrates and freshwater fish. Furthermore, biodiversity in the Indian Ocean and near the Asian coasts is mostly affected by wildlife exploitation and cultivation compared to biological invasions in the Pacific and Atlantic insular regions. We highlighted specific associations of threats at different scales, showing that the analysis of each threat in isolation might be inadequate for developing effective conservation policies and managements.