Global diversity patterns in marine fouling communities - exploring latitudinal effects and the local-regional richness relationship

Fouling communities are distributed worldwide, particularly in shallow and exposed marine systems. Due to their fast growth and their capacity to settle on artificial surfaces, these assemblages represent a suitable study system for ecologists and are therefore often used to investigate ecological models. Investigating broad scale ecological models has been of key interest since the time of the famous naturalist Charles Darwin. Two examples of well recognized macro-ecological patterns are i) the ‘latitudinal gradient of species richness’ and ii) the ‘relationship between local and regional diversity’. The first is the oldest paradigm about a large-scale ecological pattern and simply states that the tropical regions are richer in species than temperate and polar regions at higher latitudes. However, when exploring global diversity patterns, it is essential to comprehend not only the importance of differences in spatial scale for the observed patterns, but also how diversity at one scale may relate to diversity at a different scale. Indeed, several studies have shown that the number of species within small localities may increase either linearly or asymptotically with regional species richness (relationship between local and regional diversity). Exploring global diversity patterns still constitutes an important challenge for ecologists because it reflects the need to determine the current status of biodiversity. With the knowledge of today’s biodiversity, we can predict its future status and, as a consequence, be able to provide new answers to its probable response to phenomena such as climate change. In the present work, I investigate global diversity patterns in marine fouling communities, mainly by examining the previously mentioned macro-ecological patterns, i.e. the latitudinal gradient of species richness and the relationship between local and regional diversity. Previous studies investigating the local-regional diversity relationship have often assessed the number of species in a region by consulting available species lists. However, regional species pools based on such inventories may include species not susceptible to recruit into the community considered because they are restricted to different habitats and seasons. With the purpose of dealing with these difficulties, a few investigations have estimated regional richness based on local samples but confirmed a strong bias in relation to sampling effort. In order to optimize the quality of regional richness estimations, the current study develops a new statistical tool for estimating regional richness based on a limited number of replicates. Using three data-sets with a large number of replicates from different temperate shallow water habitats, I compare common richness estimators against the asymptote of the species accumulation curve, which was used as a reference for true regional richness. Subsequently and more importantly, the mis-estimation was quantified as a function of sampling effort. To complete this work, the relationship between local and regional diversity was expanded by integrating two categories of diversity (taxonomic and functional) and different successional stages at two different scales: European and global. At the European scale, the shape of the pattern was compared for different methods in assessing regional richness: species colonizing during a given period (transient regional richness) versus species colonizing during any phase of the experiment (total regional richness). At the global scale, I further examine whether the diversity of local communities is affected by parameters other than regional richness, such as number of functional groups or availability of resources. The results of this investigation support a clear influence of latitude on local species richness in marine fouling communities. In Chapter I, I show that tropical regions hold more marine fouling species when compared to areas at higher latitudes. In what concerns the regional richness assessment, I conclude that regional richness can be estimated based on a limited number of samples and that the quality of the estimation increases with sample effort. Moreover, the strength of the inevitable mis-estimation can be quantified (Chapter II). In addition, at the European scale (Chapter III), it was found that the shape of the relationship between local and regional diversity is sensitive to successional stage, the way regional richness is estimated and the dimension of diversity considered. The relevant regional richness, i.e. the regionally available colonizers, seems to vary in time and is larger when pooling all sampling events. As a consequence, the relationship between local and regional diversity is also influenced by the method in which regional richness is estimated. At a global scale (Chapter IV), the relationship between local and regional diversity in fouling assemblages is also affected by the succession process, if either taxonomic or functional diversity are considered. Local taxonomic diversity exhibits saturation at early stages of succession while saturation of local functional richness occurs later. In addition, functional groups were reported as the most influential predictor for local species richness

Diversity of Bugulidae (Bryozoa, Cheilostomata) colonizing artificial substrates in the Madeira Archipelago (NE Atlantic Ocean)

Until very recently the Madeira Archipelago registered a total of eight Bugulidae species. In the present study we include descriptions of seven Bugulidae species, now with Scanning Electron Microscopy images, with four new records for the Archipelago: Bugulina fulva and Bugulina simplex for Madeira Island and Bugula neritina and Crisularia gracilis for the neighbouring Island of Porto Santo. Furthermore, we report the correction of the previous identification of Bugulina calathus minor earlier reported from Funchal harbour in 1998, now as Bugulina flabellata. This study is part of an ongoing monitoring program for detecting non-indigenous species in all marinas from the Madeira archipelago, between 2007 and 2015. Specimens were collected in previously deployed PVC settling plates, marina pontoons, and also on recreational hull vessels while performing dry dock inspections at a local shipyard. Our study reveals that the Madeira archipelago now registers a total of ten Bugulidae species, contributing therefore to the total bryozoan fauna of the Archipelago, now with more than 100 records. These numbers could increase, as Madeira is considered to be a “hotspot” for bryozoan diversity when compared to other nearby regions. Finally, hull fouling is considered as the most likely vector of introduction for the non-indigenous species of Bugulidae detected in MadeiraP. Ramalhosa was partially funded by the Project Observatório Oceânico da Madeira-OOM (M1420-01-0145-FEDER-000001), co-financed by the Madeira Regional Operational Programme (Madeira 14-20), under the Portugal 2020 strategy, through the European Regional Development Fund (ERDF). J. Canning-Clode was supported by a starting grant in the framework of the 2014 FCT Investigator Programme (IF/01606/2014/CP1230/CT0001). The work of J. Souto was supported by the Austrian Science Fund (FWF, Lise Meitner Program, Grant M1444-B25). This is contribution number 31 of Marine Biology Station of FunchalS

Three non-indigenous species from Madeira harbors, including a new species of Parasmittina (Bryozoa)

During a study investigating the identity and abundance of fouling non-indigenous species in marinas from the Madeira Archipelago, three species of bryozoans were detected on experimental settlement plates. These three species are described and figured. Celleporaria inaudita was previously only known from Vanuatu (South Pacific Ocean) and Safaga Bay (Red Sea). Parasmittina alba was previously only known from the Brazilian coast. The origin of Parasmitina multiaviculata sp. nov. is unknown. Secondary introduction by anthropogenic vectors (via hull fouling of recreational vessels) seems the most plausible explanation for the presence of these species in the Madeira IslandsThe work of J.S. was supported by the Austrian Science Fund (FWF, Lise Meitner Program M1444-B25 and Project Number AP28954-B29). P. Ramalhosa holds a research fellowship in the Project M1420-01-0145-FEDER-000001 — project Observatório Oceânico da Madeira (OOM). J. Canning-Clode was supported by a starting grant in the framework of the 2014 FCT Investigator Programme (IF/01606/2014/CP1230/CT0001)S

Local-regional richness relationship in fouling assemblages - Effects of succession

The number of species in a local habitat depends on local and regional processes. One common approach to explore ecological saturation of local richness has been to plot local versus regional richness. We expand this approach by incorporating two dimensions of diversity - taxonomic and functional - and different successional ages of marine fouling communities. In four different biogeographic regions (Mediterranean Sea, NE Atlantic, Western Baltic Sea and North Sea) 60 experimental units made from artificial substratum were deployed for colonization. Local richness was assessed as the average number of species and functional groups (FG) per unit area while regional richness was estimated as the estimated (Jack 2) asymptote of the accumulation curves for species or FG in local panel communities. Our findings indicate that the nature of the relationship between local and regional diversity is sensitive to successional stage and the dimension of diversity considered. However, as a general pattern, for taxonomic and functional richness, the slope of the local-regional relationship increased in the course of succession. We discuss how this pattern could have been produced by a combination of low number of recruiting species and incomplete competitive exclusion as is typical for early Successio

First record of the marine snail Xenophora crispa (Gastropoda: Xenophoridae) from Madeira Island (Northeastern Atlantic Ocean)

The marine snail Xenophora crispa (d' Orbigny, 1847) is recorded for the first time in Madeira Island (NE Atlantic). This species is currently distributed throughout the central and western Mediterranean, western Atlantic from France (Gulf of Biscay) to North Africa (up to Morocco), including the Archipelagos of the Azores, Canary Islands, and now Madeira.PR is funded by the project (UIDB/04292/2020) granted to MARE UI&I and partially funded by the Project Observatório Oceânico da Madeira-OOM (M1420-01-0145-FEDER-000001), co-financed by the Madeira Regional Operational Programme (Madeira 14-20), under the Portugal 2020 strategy, through the European Regional Development Fund (ERDF). JCC was funded by national funds through FCT- Fundação para a Ciência e a Tecnologia, I.P., under the Scientific Employment Stimulus Institutional Call (CEECINST/00098/2018). JGM was supported by a post-doctoral research fellowship by Agência Regional para o Desenvolvimento da Investigação, Tecnologia e Inovação (ARDITI-M1420-09-5369-FSE-000002). Finally, this study had the support of Fundação para a Ciência e Tecnologia (FCT), through the strategic project (UIDB/04292/2020) granted to MARE UI&I.info:eu-repo/semantics/publishedVersio