Forging sustainability

Genetic assessment of a successful invasion: Population genetics of the Egyptian mongoose (Herpestes ichneumon) in Portugal
Coordinator - Carlos Fonseca
Programme - PTDC/BIA-BEC/104401/2008
Execution dates - 2010-04-01 - 2013-03-31 (36 Months)
Funding Entity - FCT
Funding for CESAM - 145000 €
Total Funding - 150000 €
Proponent Institution - Universidade de Aveiro
Participating Institutions
Universidade de Évora
Museu de História Natural de Paris

Biological invasions are one of the major threats to agriculture, human health and ecosystem sustainability. Invasive species, once established, often constitute an irreversible event that has severe consequences on the environment. To provide appropriate measures of invasive species management, it is important to understand the spatial structure, dispersal and population dynamics in those non-native species in their invaded ranges (Edwards et al. 2004). To achieve this goal, the combination of molecular techniques with ecological data can be extremely useful for improving the understanding of the dynamics, population structure and biology of many invasive species (DeYoung et al. 2005). In invasive biology, the main challenge is to provide a sufficiently exhaustive picture of the characterization of the introduced populations to understand their dynamics and spread across invaded ranges. This is a difficult task given that those populations are at non-equilibrium with their environment, but is also a great opportunity to study micro-evolutionary, rapid processes in real-time environments (Sax et al. 2007).

Currently one of the most abundant and widespread carnivores in Portugal is the historically introduced, Egyptian mongoose (Herpestes ichneumon; Carnivora). Restricted to southern Portugal until recently, the Egyptian mongoose is now expanding to the northern regions of the country (Borralho et al 1996). Despite the large, yearly hunting intakes the species represents (>6,400 animals captured in the 2006/2007 hunting season), no studies have to date tried to use this amount of available data to quantify and understand the population dynamics of this successful invader. Our project aims is assessing the genetic variability of the Egyptian mongoose in Portugal through an analysis combining mitochondrial DNA, Y-linked genes and microsatellites. We will notably compare the genetic structuring among Portuguese regions with higher mongoose densities (southern Portugal) and those with lower densities (northern Portugal), and determine migration mechanisms in relation to the sex and age of the colonizing individuals. Our project relies on the assumption that population dynamics and chances of invasive success are -at least partly- shaped by the genetic characteristics and population demography of species. We are thus convinced that it constitutes a great and unique opportunity to study ongoing processes of a successful invader in Portugal, and to provide applications in terms of management of invasive species in general. The research team of this project has strong knowledge and experience on genetic and ecological aspects of mammals, including carnivores, and they have already participated in very important studies focusing on mammal ecology and genetics that should largely contribute to reach the aims of this research.

Our project meets the state-of-the-art of the invasion biology field because we use (1) a top-down approach, from a global phylogeographic approach of the Egyptian mongoose in the Mediterranean Basin that should replace the Portuguese populations within a larger framework of introduction events to a population genetics approach at a finer scale (Portugal), where we will characterize micro-evolutionary processes and demographic dynamics, and (2) a combination of markers with different heritabilities (matrilineal, patrilineal, and biparental) to get a comprehensive picture of population structure and characterize in detail population-level parameters such as gene flow, introgression and demographic dynamics. Importantly, the combination of ecological surveys with genetic assessments is an original aspect of the project, which constitutes a strong point in achieving our objective of unravelling the processes that underlie the recent range expansion of the Egyptian mongoose in Portugal.
We predict that the Egyptian mongoose has suffered a successive alternation of range contraction and expansion within the last ca. 80 years in Portugal, due to drastic changes in agricultural management, which should be testable through our genetic characterization of populations. Our project should result in a significant number of high-impact collaborative publications where (1), from a theoretical point of view, critical micro-evolutionary processes at the origin of successful biological invasions should be better understood, and (2), on a more applied perspective, management guidelines should be provided as concerns the Egyptian mongoose in Portugal.

Members on this project
Carlos M. M. S. Fonseca
Principal Researcher
Tânia Q. Barros
Grant holder

CESAM Funding: