Saltar para o conteúdo principal

FCCNFCT Digital Services

Access the national information on scientific and technological funding in Portugal

Activity Funded

Effects of INvasive Acacia dealbata on the detrital pathway in STREAMS

Efeitos da invasão por mimosa na via detrítica em ribeiros

Reference
2023.13656.PEX
Project Start Date
2025-01-01
Project End Date
2026-12-31
Principal Investigator
Scientific Area
Natural sciences
Funding Program
Concurso de Projetos Exploratórios em Todos os Domínios Científicos 2023

Abstract

Biological invasions are a major cause of biodiversity loss and altered ecosystem functioning worldwide (Brondízio&al2019; Roy&al2023). Plant invasion of riparian areas can have strong effects on stream communities and functioning (Ferreira&al2021). Australian Acacia species are top invaders in Mediterranean areas worldwide, including central Portugal where invasion by A. dealbata is one of the most important land use changes in small/medium sizes hydrographical basins (land cover up to 43%; Ferreira&al2021). Being a fast-growing, evergreen, and nitrogen-fixing species, A. dealbata invasion can affect streams by promoting (i) increases in dissolved nutrient availability (due to leaching from nutrient-rich soils and decomposition of nutrient-rich plant detritus), (ii) decreases in water availability (due to high evapotranspiration from dense evergreen and fast-growing stands), and (iii) changes in plant detritus inputs to streams (e.g. in terms of seasonality, composition, quality) (Ferreira&al2021; Pereira&al in press). Since aquatic communities in forest streams heavily depend on plant detritus inputs from the surrounding vegetation as a source of energy, carbon and nutrients (Kominoski&al2013), changes in these inputs promoted by A. dealbata invasion can potentially affect microbial decomposers and detritus decomposition. Microbial decomposers are key components of stream ecosystems as they promote the transfer of detritus carbon and nutrients into higher trophic levels, leadingto detritus decomposition that is a key ecosystem process allowing for the cycling of carbon and nutrients (Hieber&Gessner2002). Therefore, it is important to assess the effects of A. dealbata invasion on nutrient inputs to streams,  on the microbial decomposer community and on the process of detritus decomposition to better understand invasion effects on stream functioning. This project aims at assessing the effects of A. dealbata invasion on detritus nutrient inputs to streams (Task 1). This will be achieved by taking advantage of litterfall samples collected monthly over one year in three streams flowingthrough native forests and three streams flowing through forests heavily invaded by A. dealbata in the scope of a previous project (2015–20; Pereira&al in press). Litterfall samples were sorted by detritus type and leaf species, dried, weighed and stored. Now they will be analyzed for determination of carbon, nitrogen and phosphorus concentrations by type and leaf species to allow estimation of monthly detritus nutrient inputs to streams (Molinero&Pozo2004). Also, this project aims at assessing the effects of the presence of A. dealbata detritus (Task 2) or detritus leachates (Task 3) on the activity and community structure of microbial decomposers and decomposition of plant detritus. This will be done by using laboratory microcosms, on which the project team is well experienced (Ferreira&al2022; Madureira&Ferreira2022). Here, we will manipulate the presence/absence of A. dealbata detritus (Task 2) or A. dealbata leachates (0%, 50%, and 100% derived from detritus collected during the flower litterfall peak and during the pod litterfall peak; unfiltered and filtered leachates will be used to isolate potential allelopathic effects; Task 3). Results will contribute to a wider understanding of the cross-ecosystem effects of A. dealbata invasion on stream communities and functioning,and inform on the effects of invasion by N-fixers more widely. Results will be particularly useful for carbon and nutrient modeling as well as for other studies addressingplant detritus decomposition (in streams as well as in the soil) as they will allow the creation of a database with carbon, nitrogen and phosphorus information for all detritus types and leaf species present in the riparian litterfall (existing databases are generally poor regarding riparian vegetation). The PI has an Auxiliary Researcher contract (2020–26), and has experience as PI, in student supervision, and in science communication. The project team is composed of stream ecologists (MARE-UC), an expert in nutrient analyses (MARE-UC), an expert on Acacia invasions and allelopathy (CFE-UC) and an expert in extraction and separation of natural compounds (CERES-UC), therefore having the knowhow to carry out the project. Three international experts on the forest-stream linkage, biodiversity effects, and plant invasions and allelopathic effects will act as consultants. The team will be complemented with 3 MSc students hired by the project; additional students will be engaged. Expected scientific outputs include 3 scientific papers, 3 presentations at congresses and 3 MSc theses (to be completed out of the project duration). Outreach activities (including 3 papers) will be carried out to promote knowledge transfer to the society.

Institutions

Main Institutions

  • Universidade de Coimbra (UC)

Funding 49.999,20 €

Fundação para a Ciência e a Tecnologia (FCT) - Portugal

49.999,20 €