Síndromes funcionais e de dispersão numa espécie exótica invasora

Populations of invasive (and native) species are often composed of quite distinct phenotypes. This situation can directly modify the performance of individuals generating quite different ecological effects. Despite their potential theoretical and management relevance, so far only a few empirical studies explored this topic. DIS-FUNCTIONAL project’s main aim is therefore to understand the complex interactions between biological traits, genetic diversity, gene regulation and ecological impacts mediated by biological invasions between and within populations, using the signal crayfish Pacifastacus leniusculus as a model. To accomplish this, a series of more specific aims will be put in place, including: 1) Characterize biological traits between and within populations; 2) Describe the genetic diversity patterns and gene expression related to metabolism and aggression between and within populations; 3) Assess possible seasonal differences in ecological effects between and within populations; 4) Develop a model that integrates biological traits and ecological impacts at relevant spatial and temporal scales. Most of the earlier studies on biological invasions focused on assessments of dispersal and ecological impacts at the species level, which may be an oversimplification as biological invasions are fundamentally a population-level phenomenon. For example, and based on very preliminary data collected in the summer of 2023, we found that the signal crayfish in the Rabaçal River (one of the rivers to be studied) present different biological traits in the core and front of the invasion. Animals in the front are larger and are male-biased when compared to the core. However, these results were based on just one population. We want to increase the number of populations to be studied and increase the degree of enquiry using a much more detailed methodological approach. We hypothesize that animals at the front of the invasion will exhibit distinct eco-morphological, physiological, and personality traits, such as larger size, higher growth, increased metabolism, and presenting more active, bold, and aggressive behaviour when compared to those located at the core. Additionally, we hypothesized that animals from the core and front will exhibit different expression in genes related to metabolism and aggression and we predict a lower genetic diversity at the front due to a lower effective population size. This may accelerate the proliferation of genes linked with higher activity and aggressiveness, thereby promoting the invasion. If our predictions are correct, we also hypothesize that the ecological impacts (e.g. consumption of prey and leaves, decomposition, nutrient cycling) will be also higher at the front of the invasion. These assessments will be performed seasonally in five different populations in order to check the repeatability of the main findings at the intra-population level or if they are context-dependent. We are also expecting higher ecological impacts during summer. Collected data will be instrumental in developing a mathematical model considering these intra-population peculiarities, which may be important for the implementation of management actions. This model will also project the distribution of the species in the studied area and will predict the main ecological impacts taking into account future climate scenarios, assuming a higher impact following an increase in temperature as expected to occur in our seasonal assessments.