Biodiversity and distribution of intertidal organisms in the E Atlantic
Since 2002, when I started my biogeographic studies along the Atlantic coast of Europe and North Africa, I have been helped by numerous people, including Nuno Queiroz, Pedro Ribeiro, Raquel Xavier, Pedro Tarroso, and my PhD supervisors António M. Santos (CIBIO, University of Porto, Portugal) and Stephen J. Hawkins (currently at the University of Southampton).

We have completed numerous fieldwork surveys along the Atlantic coast of Europe and North Africa (between Scotland and Morocco), providing a quite comprehensive dataset on the distribution and abundance of more than two hundred species of intertidal algae and animals. This high resolution, multi-species dataset represents an important baseline against which future changes in species distributions can be compared to.
Fieldwork with Pedro Ribeiro at Sidi Abderrahmane, Morocco
 
Effects of climate change on species distributions
We identified several species as sensitive indicators of climate change. One example is the warm-water limpet Patella rustica. Starting in the late 1990s, rocky shores in N Portugal were colonized by this species, leading to the bridging of a historical distributional gap known since the 1900s. We analyzed long-term oceanographic data, showing that these changes in distribution were tightly connected to increases in coastal temperature and associated changes in sea circulation. Please click HERE to read the paper.

However (and contrarily to what could be expected) fieldwork surveys have shown that the ranges of many other species did not changing at the same rate and/or in the same direction. These results are extremely relevant because they show that generalizations about poleward shifts in distribution in response to climate change should not be taken lightly. Data suggests that even species that are apparently responding to climate warming have complex, non-linear interactions with third-party factors like habitat availability or other organisms. More details can be found on THIS publication.
 
Patella rustica, a warm-water species expanding its distribution
Cold-water species like P. canaliculata are restricted to high latitudes
 
 
Analysis of multispecies distributional limits
Regions of abrupt environmental clines frequently limit the occurrence of multiple and unrelated species, collapsing their distribution limits to a narrow geographic area. Changes on multi-species range limits are therefore robust indicators of environmental change, allowing us to track impacts of global warming.

During my PhD, me and A. M. Santos (CIBIO, University of Porto, Portugal) developed an analytical method to objectively define biogeographic discontinuities along a linear transect (like a coastline) for a high number of species. The main feature in this new technique is its ability to work with unevenly distributed data, which can be particularly useful for studying ecological communities from patchy habitats (such as the rocky shores). THIS publication describes the method in detail, and a pratical application can be found HERE.
 
The effects of warming can also be studied at the community level
 
 
Centennial-scale reconstruction of coastal SSTs
In collaboration with David Wethey (University of South Carolina, USA), I have reconstructed monthly coastal sea surface temperatures (SSTs) for more than one century (1900 to 2008) for both European and US coasts, using in situ data from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). These data are extremely important not only to correlate with current changes in species distributions, but also to use as input in bioclimatic models and hindcast studies, work done in collaboration with Sarah Berke (Smithsonian Environmental Research Center), David Wethey, Jerry Hilbish, Sarah Woodin and Sierra Jones (University of South Carolina, USA).

Results have shown the key role of SST in driving the distributional range of several marine invertebrate species (e.g., Mytilus galloprovincialis, M. edulis, Diopatra neapolitana, Chthamalus stellatus, C. montagui, Semibalanus balanoides and Patella rustica) along the NE and NW Atlantic coasts. Click HERE, HERE and HERE for the related literature.
 
SST was used to model the distribution of Diopatra neapolitana
 
 
Distribution of invertebrates in relation to their host algae
Working together with Sílvia Pereira and under the supervision of A. M. Santos (CIBIO, University of Porto, Portugal), I have looked at the relation between the distribution of small intertidal crustaceans and their host algae, along the Portuguese coast. Interestingly, and contrary to what we were expecting a priori, epifaunal occurrence, abundance and diversity were not related with geographical changes in the identity of the dominant algal species. Instead, we found a clear gradient of species substitution from north to south, in agreement with the major cline in temperature. This manuscript can be downloaded HERE.
 
Synisoma lancifer can be frequently found among Gelidium corneum
 
 
Biogeographic patterns of the genus Stenosoma
I had the luck to collaborate in several studies led by Raquel Xavier (CIBIO, University of Porto, Portugal), in which genetic data was used to clarify intriguing biogeographic patterns. In one project, we analyzed the apparently rapid geographic expansion of the isopod Stenosoma nadejda throughout the SW coast of Portugal in the late 2000s. At first, we thought that the recent warming was driving the expansion of the species. Genetic data, however, showed that populations of S. nadejda were already in the Atlantic for a long time, thus discarding the "rapid expansion" hypothesis. The new evidence suggested that historical surveys either overlooked this species or failed in their taxonomic identification. Click HERE for the manuscript.

In another study, field observations and bibliographic data on the distribution of Stenosoma species, combined with the discovery of a new species, suggested that the Atlantic-Mediterranean transition had a major role in the diversification of this genus. Furthermore, given the strong differentiation of the North African Atlantic clade of S. nadejda, it is probable that this region has served as a glacial refugium. The coincident genetic patterns of the "west Mediterranean clades" of S. nadejda and the newly discovered species showed the close biogeographic affinity between the Alboran island and the west Mediterranean, suggesting that connectivity patterns in the area that are different from what was previously thought. This maniscript can be downloaded HERE.
 
Cala Iris, Morocco, a collection location for Stenosoma nadejda
Collecting isopods with Raquel Xavier and Saliha Zenboudji
 
 
Thermal stress and coral reefs
In a study led by Karl Castillo (University of North Carolina at Chapel Hill, USA), we showed that over the last 27 years in the western Caribbean Sea, skeletal extension within forereef colonies of the reef-building coral Siderastrea siderea declined with increasing seawater temperature, while extension rates of backreef and nearshore colonies were not impacted. These results suggested that forereef conspecifics of Siderastrea siderea are more vulnerable to ocean warming than their backreef and nearshore counterparts, highlighting the importance of understanding cross-reef differences in coral thermal tolerance for managing coral reef ecosystems in an era of rapid global and regional climate change. To read this paper click HERE.

Also with Karl Castillo (University of South Carolina and University of North Carolina at Chapel Hill, USA), I was involved in testing the effectiveness of remotely sensed SSTs for measuring subtidal thermal stress in coral reef environments. We showed that for Belizean coral reefs there is a negative (cool) bias for both MODIS TERRA and AQUA remote sensed SSTs when compared with in situ measurements. Understanding these biases does not only provide a better evaluation of the thermal regime on individual reefs, but also allows one to better compare the environment from different coral reefs. The results from this project are relevant for a broad number of biogeographic studies that typically rely on satellite-derived SST. To access this manuscript click HERE.

 
Karl Castillo extracting a coral core
We compared satellite SST with in-situ data from Belize´s coral reefs
 
 
Experimental ecology
Since 2002 I have been involved in some field experiments. For example, under the supervision of António M. Santos and in collaboration with Nuno Queiroz, Pedro Ribeiro and Carla Felga (University of Porto, Portugal), we transplanted Himanthalia elongata (a cold-water alga species)from stable populations in N Portugal (the current southern distributional limit of this species), to southern shores from where it has been extinct since the 1980s. Results from this study suggested that contemporary SSTs are not hampering reproductive growth as no significant differences were observed between transplanted and control individuals. However, individuals transplanted to southern locations were overgrown by sabellarian reefs or subjected to intense grazing which was never observed within the current range. Hence, biological interactions might have played a more significant role southern extinction of H. elongata than previously anticipated. These findings are important since evidence for the role of biological interactions setting equatorialward limits is scarce in literature.
 
With Nuno Queiroz depoying experimental cages in the intertidal
 
 
Movement patterns of large pelagic predators
I had also the luck to participate in some studies led by Nuno Queiroz (CIBIO, University of Porto) and David Sims (Marine Biological association of the UK) in which we tagged and studied the movement patterns of blue sharks (Prionace glauca) and sunfish (Mola mola) in the NE Atlantic. Using tag/recapture data from blue sharks initially caught off the Portuguese coast, we showed that in the north-east Atlantic, seasonal sea surface temperature variation plays an important role in determining the latitudinal migrations of this species. Click HERE to download the paper.

More recently, we accomplished with success the first world GPS tracking of a fish (Mola mola). This work yielded tracks of unparalleled accuracy at an unprecedented level of resolution. Movement information was then contrasted with high-resolution, remote-sensed environmental data (oceanic temperature, currents, bathymetry and chlorophyll concentration). Click HERE to access this paper.
 
Blue shark (Prionace glauca) being caught for tag and release