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Publications

‘Solo datasets’: unexpected behavioural patterns uncovered by acoustic monitoring of single individuals

Publication . Baeyaert, Joffrey; Abecasis, David; Afonso, Pedro; Graça, Gonçalo; Erzini, Karim; Fontes, Jorge

A holistic understanding of the life-history strategies of marine populations is often hindered by complex population dynamics, exacerbated by an intricate movement ecology across their life history (Nathan et al. 2008; Parsons et al. 2008; Jeltsch et al. 2013). Movement patterns and spatial ecology can vary spatially and temporally for different reasons, mainly related to the organism’s life history and environmental variability (Abecasis et al. 2009, 2013; Afonso et al. 2009). Changes in spatial use and movement can occur daily when visiting feeding grounds or avoiding predators, or seasonally, when sexually mature individuals migrate to spawning/breeding grounds (Kozakiewicz 1995; Sundström et al. 2001). However, observed shifts in spatial use and movement patterns, as a result of behavioural plasticity, may also vary greatly from one individual to another of the same species and/or population (Afonso et al. 2009). Further, ontogeny can also play an important role and explain a possible change in individual spatial variation. Noticeable differences in the behaviour and movements of mature and immature individuals have been documented in various marine organisms (Lowe et al. 1996; Lecchini and Galzin 2005). Permanent habitat shifts have been associated with ontogenesis in pigeye sharks (Carcharhinus amboinensis), moving from inshore to offshore areas after reaching maturity (Knip et al. 2011).

2018Journal article

Open access

Environmental representativity in marine protected area networks over large and partly unexplored seascapes

Publication . Stratoudakis, Yorgos; Hilário, Ana; Ribeiro, Cláudia; Abecasis, David; Gonçalves, Emanuel J.; Andrade, Francisco; Carreira, Gilberto P.; Gonçalves, Jorge Manuel Santos; Freitas, Luis; Pinheiro, Luis Menezes; Batista, Marisa I.; Henriques, Miguel; Oliveira, Paulo B.; Oliveira, Paulo; Afonso, Pedro; Arriegas, Pedro Ivo; Henriques, Sofia

Converting assemblages of marine protected areas (MPAs) into functional MPA networks requires political will, multidisciplinary information, coordinated action and time. We developed a new framework to assist planning environmental representativity in a network across the marine space of Portugal, responding to a political commitment to protect 14% of its area by 2020. An aggregate conservation value was estimated for each of the 27 habitats identified, from intertidal waters to the deep sea. This value was based on expert-judgment scoring for environmental properties and features relevant for conservation, chosen to reflect the strategic objectives of the network, thus providing an objective link between conservation commitments and habitat representativity in space. Additionally, habitats' vulnerability to existing anthropogenic pressures and sensitivity to climate change were also scored. The area coverage of each habitat in Portugal and within existing MPAs (regionally and nationally) was assigned to a scale of five orders of magnitude (from < 0.01% to >10%) to assess rarity and existing representation. Aggregate conservation value per habitat was negatively correlated with area coverage, positively correlated with vulnerability and was not correlated with sensitivity. The proposed framework offers a multi-dimensional support tool for MPA network development, in particular regarding the prioritization of new habitats to protect, when the goal is to achieve specific targets while ensuring representativity across large areas and complex habitat mosaics. It requires less information and computation effort in comparison to more quantitative approaches, while still providing an objective instrument to scrutinize progress on the implementation of politically set conservation targets.

2019Journal article

Open access

A fine-tuned global distribution dataset of marine forests

Publication . Assis, J.; Fragkopoulou, Eliza; Frade, Duarte; Neiva, J.; Oliveira, André; Abecasis, David; Faugeron, Sylvain; Serrao, Ester

Species distribution records are a prerequisite to follow climate-induced range shifts across space and time. However, synthesizing information from various sources such as peer-reviewed literature, herbaria, digital repositories and citizen science initiatives is not only costly and time consuming, but also challenging, as data may contain thematic and taxonomic errors and generally lack standardized formats. We address this gap for important marine ecosystem-structuring species of large brown algae and seagrasses. We gathered distribution records from various sources and provide a fine-tuned dataset with ~2.8 million dereplicated records, taxonomically standardized for 682 species, and considering important physiological and biogeographical traits. Specifically, a flagging system was implemented to signal potentially incorrect records reported on land, in regions with limiting light conditions for photosynthesis, and outside the known distribution of species, as inferred from the most recent published literature. We document the procedure and provide a dataset in tabular format based on Darwin Core Standard (DwC), alongside with a set of functions in R language for data management and visualization.

2020Journal article

Open access

Diel and seasonal changes in the spatial behaviour of a soft-sediment fish (Solea senegalensis) inside a marine reserve

Publication . Gandra, Miguel; Erzini, Karim; Abecasis, David

The protection provided by marine reserves directly depends on the short and long-term movement patterns of local organisms. Although there has been an increase in research assessing the behavioural patterns of fishes in reef-based habitats, there is still a paucity of studies addressing the benefits of marine protected areas (MPAs) for soft-sediment species. Here, we investigated both diel and seasonal shifts in spatial behaviour of the Senegalese sole, Solea senegalensis, within a recently-established marine reserve using long-term passive acoustic telemetry. Results showed variable levels of site attachment, with nearly half of the fish (n = 8) disappearing from the monitored area within 30 days, and the remaining (n = 9) being detected for periods up to 293 days and spending 95% of their time within an average area of 0.88 ± 0.46 km2. Although detection frequency was higher during daytime periods, the larger home range areas and greater movement observed during nighttime periods are consistent with a nocturnal activity regime, which might increase the vulnerability of S. senegalensis to illegal fishing. Additionally, patterns observed during the spawning season suggest the existence of shifts in habitat use linked with reproductive activity, opening the door to further research on soles' fine-scale interaction dynamics. Overall, this study provides novel insights into the ecology of a flatfish species and suggests that small no-take areas encompassing suitable soft-sediment habitats can offer adequate protection to at least part of the Senegalese sole population.

2018Journal article

Open access

An ecological framework for the development of a national MPA network

Publication . Abecasis, David; Afonso, Pedro; Erzini, Karim

Isolated marine protected areas (MPAs) may not be enough to sustain viable populations of marine species, particularly the many small coastal MPAs which resulted due to social, economic and political constraints. Properly designed MPA networks can circumvent such limitations due to their potential synergistic positive effects, but this crucial step is frequently obstructed by lack of baseline ecological information. In this paper, we use systematic conservation planning on European Nature Information System coastal habitat information available for Portugal to demonstrate how an ecologically coherent nation-wide MPA network can be designed. We used the software Marxan to obtain near optimal solutions for each of three pre-determined conservation targets (10%, 30% and 50% protection) while maintaining the cost of including conservation units as low as possible. Marxan solutions were subsequently optimized with MinPatch by keeping each MPA above a minimum size that reflects the existing information on habitat use by some key marine fishes. Results show that 10% protection for all habitats would only require a relativelly small increase in the number (from 6 to 10) and area (from 479 km(2) to 509 km(2)) of already existing MPAs in mainland Portugal whereas substantial increases would be required to achieve the 50% target. This rather simple approach offers the added benefit of allowing design improvement as more relevant ecological information becomes available, including deeper habitat mapping across the whole continental shelf, allowing a coherent, adaptive and inclusive optimal MPA network to be designed.

2017-05Journal article

Open access