Dr. Jean-Pierre Rossi

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I am a senior researcher at INRAE in Montpellier, France.

My work is about spatial ecology of forest insects, invasion biology and phytosanitary risk assessment

My research focuses on the spatial ecology of insect pests and aims to better understand the environmental determinisms of population dynamics in space. I mainly work on two scales: the scale of landscapes and the continental scale which corresponds to the geographical distribution of species. Ecological processes often differ as well as the time scales at which they act and therefore these two approaches are complementary.

Species distribution modeling to better understand the impact of climate change on pest risk

A significant research effort is now devoted to identifying the environmental factors controlling the distribution areas of crop or forest pest species. This work concerns native pests as well as invasive species. Ecological niche modeling is a useful tool for estimating the potential geographical distribution of species of interest and simulating its evolution under different climate change scenarios. Estimating the potential distribution of a species is important information for carrying out pest risk analyses.

Although preventing the introduction and spread of alien pests in the context of ever-increasing international trade seems like an elusive goal, substantial improvements in our management of invasive species could be achieved by improving prevention, monitoring and public awareness. The most effective way to contain biological invasions is to prevent the introduction of alien species. Identifying potential invaders and areas at risk is an essential aspect of preparedness. This implies being able to mobilize a rapid, planned and coordinated response capacity as well as a panel of trained experts with a good knowledge of the risk associated with pests. Species distribution models (SDMs) are well-known tools for modeling the climatic niches of species and assessing areas with suitable climatic conditions. This information is useful to prepare for a possible introduction (“preparedness”). It becomes possible to guide epidemiological surveillance, inform the public and professional sectors. We can also build citizen science tools to collect ecological data very quickly and on a large scale, which is always valuable during a biological invasion (Chartois et al 2021, Streito et al 2021).

Climate change translates into profound changes in the environmental conditions that species face. For some species, the warming observed in Europe allows an expansion towards higher latitudes. This is the case of the pine processionary (Roques 2015) or the oak processionary (Godefroid et al 2020). On the other hand, it would be wrong to believe that global changes are systematically favorable to biological invasions. We have recently shown that future climatic conditions will be globally unfavorable to the marmorated stink bug except in Europe where this species will find increasingly favorable conditions, particularly in the northern part of the continent (Streito et al 2021).

Understand the impact of the landscape on the dynamics of forest pests

The landscape scale is the preferred spatial scale for understanding insect population dynamics and relationships with environmental heterogeneity (i.e. landscape structure and composition). Many land management and planning options are considered at this scale, which is also relevant for addressing issues of maintaining biodiversity. It is also the scale at which inventories are carried out to monitor changes in the health of forests and crops and identify possible sources of proliferation of pest organisms.

To understand the dynamics of forest pests, it is necessary to go beyond the strict framework of forests and integrate the other compartments of the landscape (agricultural plots, urban areas, etc.). Today, we are trying to understand the spatial dynamics of certain species such as the pine processionary moth Thaumetopoea pityocampa (Lepidoptera Notodontidae) by considering all the components of the landscape and in particular urban and peri-urban environments. We recently highlighted the major role played by trees outside forests (TOF) in the spatial dynamics of the insect and its rise towards the north of France due to global warming. TOFs allow the processionary to disperse in large agricultural regions where forest cover is very limited, which facilitates the geographic expansion of this species (Rossi et al 2016a).

Just like rural areas, urban and peri-urban environments harbor trees outside forests which are called “urban trees”. These trees play an important role in the quality of life in the city but can also pose problems (we speak of “ecosystemic disservices”) by producing allergenic pollen or by harboring species representing a danger to public health. This is the case of the pine and oak processionaries whose stinging caterpillars can cause very severe lesions in domestic animals and allergies in humans. For such species, a good knowledge of the distribution of trees in the city allows the monitoring of the infestation and the development of a risk map at the scale of the agglomerations. These maps are used to improve public information and better manage the pine processionnary (Rossi et al 2016b).

References

  • Chartois, M., Streito, J.-C., Pierre, É., Armand, J.-M., Gaudin, J., Rossi, J.-P., 2021. A crowdsourcing approach to track the expansion of the brown marmorated stinkbug Halyomorpha halys (Stål, 1855) in France. Biodiversity Data Journal 9, e66335.

  • Godefroid, M., Meurisse, N., Groenen, F., Kerdelhué, C., Rossi, J.-P., 2020. Current and future distribution of the invasive oak processionary moth. Biological Invasions 22, 523–534.

  • Roques, A. (Ed.), 2015. Processionary Moths and Climate Change: An Update. Springer, Dordrecht.

  • Rossi, Jean-Pierre, Garcia, J., Roques, A., Rousselet, J., 2016a. Trees outside forests in agricultural landscapes: spatial distribution and impact on habitat connectivity for forest organisms. Landscape Ecology 31, 243–254.

  • Rossi, J.-P., Imbault, V., Lamant, T., Rousselet, J., 2016b. A citywide survey of the pine processionary moth Thaumetopoea pityocampa spatial distribution in Orléans (France). Urban Forestry & Urban Greening 20, 71–80.

  • Streito, J.-C., Chartois, M., Pierre, É., Dusoulier, F., Armand, J.-M., Gaudin, J., Rossi, J.-P., 2021. Citizen science and niche modeling to track and forecast the expansion of the brown marmorated stinkbug Halyomorpha halys (Stål, 1855). Scientific Reports 11, 11421.