Habitat Attributes Dictate the Roles of Dispersal and Environmental Filtering on Metacommunity Assembly at Coastal Soft‑Bottom Ecosystems

Tracking the effects of habitat attributes on species distribution is pivotal to the understanding of community assembly across space and time. We used the elements of metacommunity (EMS), which evaluates coherence, turnover, and boundary clumping of species, to access the spatial patterns of nematodes from three coastal habitats with increasing degree to wave exposure, namely, mangroves, estuarine unvegetated tidal flats, and sandy beaches. Each habitat was sampled in four locations, hundreds of kilometers apart from each other. We hypothesized that (1) coastal habitats act as metacommunity boundaries and drive positive turnover and clumped distribution of species and (2) metacommunity structure within coastal habitats depends on the habitats’ degree to wave exposure since wave energy generally decreases sediment heterogeneity and favors connectivity among locations. Habitats were the main drivers of species turnover, with tidal flats harboring a transitional assemblage between mangrove and sandy beach. Metacommunities from the different habitats showed distinct patterns of organization among locations. Mangroves were characterized by species loss, with smaller areas of mangroves harboring a subset of the species pool present on larger areas of mangroves. Tidal flats showed positive species turnover among the different estuaries, with co-occurring species responding as a group to environmental variations. Both patterns indicate environmental filtering as the main driver at these less wave-exposed habitats. At sandy beaches, in contrast, metacommunity displayed a random pattern, suggesting high connectivity among locations. Our study confirmed that habitat attributes may induce distinct mechanisms of metacommunity assembly at coastal soft-bottom ecosystems.publishedVersio

Benthic Habitat Quality Assessment in Estuarine Intertidal Flats Based on Long-Term Data with Focus on Responses to Eco-Restoration Activity

A long-term assessment of the benthic habitat quality of intertidal flats in Liaohe Estuary was conducted by three integrating ecological indices, AZTI’s Marine Biotic Index (AMBI), Multivariate-AMBI (M-AMBI), and Shannon–Wiener diversity index (H′) based on macrobenthos data from 2013 to 2020. The results showed that the macrobenthic communities were characterized by indifferent and sensitive species of AMBI ecological groups. The annual ranges of H′, AMBI, and M-AMBI were 0.77–1.56, 1.44–3.73 and 0.36–0.54, respectively. Noticeable differences were found among assessment obtained by these biotic indices. Approximately 100%, 24%, and 78% sampling sites had “moderate”, “poor”, and “bad” statuses as assessed by H′, AMBI, and M-AMBI, respectively. Compared with H′ and AMBI, M-AMBI may be more applicable to evaluate the benthic habitat quality of intertidal flats in Liaohe Estuary. Results suggest that the benthic habitat quality in the middle parts of intertidal flats still had an unacceptable status and has not improved radically to date after large-scale “mariculture ponds restored to intertidal flats”.publishedVersio

Identifying "vital attributes" for assessing disturbance-recovery potential of seafloor communities

Despite a long history of disturbance–recovery research, we still lack a generalizable understanding of the attributes that drive community recovery potential in seafloor ecosystems. Marine soft‐sediment ecosystems encompass a range of heterogeneity from simple low‐diversity habitats with limited biogenic structure, to species‐rich systems with complex biogenic habitat structure. These differences in biological heterogeneity are a product of natural conditions and disturbance regimes. To search for unifying attributes, we explore whether a set of simple traits can characterize community disturbance–recovery potential using seafloor patch‐disturbance experiments conducted in two different soft‐sediment landscapes. The two landscapes represent two ends of a spectrum of landscape biotic heterogeneity in order to consider multi‐scale disturbance–recovery processes. We consider traits at different levels of biological organization, from the biological traits of individual species, to the traits of species at the landscape scale associated with their occurrence across the landscape and their ability to be dominant. We show that in a biotically heterogeneous landscape (Kawau Bay, New Zealand), seafloor community recovery is stochastic, there is high species turnover, and the landscape‐scale traits are good predictors of recovery. In contrast, in a biotically homogeneous landscape (Baltic Sea), the options for recovery are constrained, the recovery pathway is thus more deterministic and the scale of recovery traits important for determining recovery switches to the individual species biological traits within the disturbed patch. Our results imply that these simple, yet sophisticated, traits can be effectively used to characterize community recovery potential and highlight the role of landscapes in providing resilience to patch‐scale disturbances.Peer reviewe

The state of the art of Xyalidae (Nematoda, Monhysterida) with reference to the Brazilian records

In the current study we provide a reviewed list of valid genera and species of Xyalidae, a widespread family of mostly marine free-living nematodes. Comments are added about the historic background and taxonomic situation of the family, all valid genera and, when necessary, diagnostic characters are given. Additionally, information about distribution and geographical location of species recorded along the Brazilian coast is provided. Our review recognized 46 valid genera, 450 valid species and 73 descriptions without enough morphological information for identification (species inquerendae). Nearly 80 % of the species inquerendae belong to Daptonema and Theristus. To avoid homonymies, two Daptonema species were renamed, Daptonema biwaensis (Tsalolikhin, 2002) new name (former Mongolotheristus timoshkini) and Daptonema vietnamensis (Gagarin and Thu, 2008) new name (former D. curvatum sensu Gagarin and Thu, 2008). Cenolaimus sapeloensis is transferred to Xyala sapeloensis comb. nov. Along the Brazilian coast 28 genera and 41 species have been recorded. The species Elzalia floresi, Metadesmolaimus tersus, Paramonohystera stricta, Pseudosteineria scopae, Rhynchonema cemae, R. veronicae, Steineria ericia, S. marcorum, S. pavo, S. tripartita, Theristus acribus, T. flevensis, T. macroflevensis, T. pertenuis, T. stranus, Trichotheristus heterus, T. setosus and Zygonemella striata have the Brazilian coast as the type locality. Among all species, three occurred across three geographic regions, while the large majority was restricted to one. Xyalidae is typically encountered in oceanic sandy beaches, with only the species belonging to Daptonema, Theristus, Trichotheristus and Zygonemella being recorded in estuarine sediments. This observation suggests that the colonization of inland waters occurred multiple times along the evolutionary history

Estudos paleoambientais interdisciplinares: dinâmica da vegetação, do ambiente marinho e inferências climáticas milenares a atuais na Costa Norte do Espírito Santo, Brasil

Estudos paleoambientais desde ~50.000 anos na costa do Brasil e, em particular, no litoral do Espírito Santo, são ainda insuficientes para servir de base a reconstituições da dinâmica da vegetação, de oscilações do nível relativo do mar e de flutuações climáticas e respectivas influências sobre a ação humana milenar. Para obter essas informações, uma equipe interdisciplinar, financiada por projetos temáticos FAPESP e CNPq, desenvolveu pesquisas correlatas na Reserva Natural Vale (RNV) e região. Para a caracterização da dinâmica da vegetação e marinha, com inferências climáticas, em locais de floresta de tabuleiros e campos naturais da RNV e região desde ~16.000 anos, utilizaram-se isótopos do C (12C, 13C e 14C) da matéria orgânica do solo e sedimentar, além de palinologia em sedimentos lacustres e terrestres. No estudo da dinâmica do ecótono floresta – campo, apresentam-se inferências preliminares sobre a evolução pedogenética dos Espodossolos associados ao campo, com ênfase às suas características físico-químicas, e também dos Argissolos, encontrados sob floresta. Finaliza-se com o estágio inicial de uma coleção de referência de fitólitos, bioindicador de vegetação utilizado em estudos paleoambientais, extraídos de plantas da floresta de tabuleiros da RNV.A equipe agradece todo o empenho dos funcionários e apoio logístico da Reserva Natural Vale, Linhares, Espírito Santo; à FAPESP através do projeto Temático 2011/00995-7 (ProjES); e ao CNPq – Universal 2012-5/470210, pelo aporte financeiro e a colaboração dos técnicos do Laboratório 14C, Liz Mary Bueno de Moraes e Thiago Casemiro Barrios de Campos, na preparação de amostras gasosas para a datação 14C.Peer Reviewe

Habitat Attributes Dictate the Roles of Dispersal and Environmental Filtering on Metacommunity Assembly at Coastal Soft‑Bottom Ecosystems

Tracking the effects of habitat attributes on species distribution is pivotal to the understanding of community assembly across space and time. We used the elements of metacommunity (EMS), which evaluates coherence, turnover, and boundary clumping of species, to access the spatial patterns of nematodes from three coastal habitats with increasing degree to wave exposure, namely, mangroves, estuarine unvegetated tidal flats, and sandy beaches. Each habitat was sampled in four locations, hundreds of kilometers apart from each other. We hypothesized that (1) coastal habitats act as metacommunity boundaries and drive positive turnover and clumped distribution of species and (2) metacommunity structure within coastal habitats depends on the habitats’ degree to wave exposure since wave energy generally decreases sediment heterogeneity and favors connectivity among locations. Habitats were the main drivers of species turnover, with tidal flats harboring a transitional assemblage between mangrove and sandy beach. Metacommunities from the different habitats showed distinct patterns of organization among locations. Mangroves were characterized by species loss, with smaller areas of mangroves harboring a subset of the species pool present on larger areas of mangroves. Tidal flats showed positive species turnover among the different estuaries, with co-occurring species responding as a group to environmental variations. Both patterns indicate environmental filtering as the main driver at these less wave-exposed habitats. At sandy beaches, in contrast, metacommunity displayed a random pattern, suggesting high connectivity among locations. Our study confirmed that habitat attributes may induce distinct mechanisms of metacommunity assembly at coastal soft-bottom ecosystems

Patrones de distribución de cangrejos ectossimbiontes y sus equinoideos anfitriones en un banco arenoso de un estuario subtropical.

Encope emarginata (Leske, 1778) are frequently observed aggregated in the sediment and variations in its spatial patterns of distribution may be a function of changes on local hydrodynamic regime. Tiny crabs, Dissodactylus crinitichelis Moreira, 1901 living associate with these irregular echinoids. It is unclear whether the presence of crabs can affect the fitness of hosts and if this effect may be dependent on the abundance of crabs that a sand dollar is capable of hosting. If we consider that sand dollars act as substrate for symbionts then, they are subject to intraspecific competition for space. Based on this assumption, we hypothesize that the abundance of crabs will be positively correlated with sand dollar size. Two sampling campaigns were made, one in September - 2011 and other in May - 2012. Sand dollars were counted and measured in situ at the tidal flat in front of Cobras’ Island (25° 29’ 5” S - 48° 25’ 48” W) in the Paranaguá Bay - Southern, Brazil. Four parallel transects were distributed between depths of 0.5 to 2 m and the number of individuals were counted in a sample area of 4 m². In another moment, 164 sand dollars and their symbionts were measured. We observed 906 specimens of E. emarginata (558 in Sep / 11 and 348 in May / 12). Sand dollar densities range from zero to 20 ind. 4 m-², and had an aggregate distribution pattern with patches of different densities within transects and periods (F2, 15 = 9.466, p < 0.01). Patches were observed near to the coast in Sep / 11 compared with May / 12. The symbionts D. crinitichelis present a more variable distribution pattern if compared with sand dollars. In Sep / 11, crabs were clumped distributed as well as sand dollars. On the other hand, in May / 12 D. crinitichelis was random distributed, displaying a distinct pattern than those observed for E. emarginata hosts. No relationship between size of E. emarginata and the number symbionts was observed (Longitudinal axes: r = - 0.021, p < 0.05; Transverse axes: r = - 0.017, p > 0.05), refuting the hypothesis that space is a limiting resource for the crabs. On the contrary, distribution patterns of D. crinitichelis were seemingly influenced by the distribution of their host population, rather than by one single host specimen. This suggests that other factors (e.g., the spatial distribution and connectivity between patches within a population of sand dollars) may be more important for the population dynamics of D. crinitichelis than competition for space per se. Encope emarginata se agrupa con frecuencia y las variaciones observadas en los sedimentos y en sus patrones espaciales de distribución pueden ser en función de los cambios en el régimen hidrodinámico local. Asociados con estos equinoideos irregulares viven pequeños cangrejos Dissodactylus crinitichelis. Si se considera que los equinoideos actúan como sustrato para sus simbiontes, estos están sujetos a competición intraespecífica por espacio. Basándose en esta suposición, fue creada la hipótesis de que la abundancia de cangrejos y el tamaño del equinoideo se correlacionan positivamente. Se hicieron dos muestreos, uno en septiembre de 2011 y otro en mayo de 2012. Los equinoideos fueron contados y medidos in situ, en la llanura de marea frente a Isla de las Cobras (25° 29’ 5” S - 48° 25’ 48” W) en la Bahía de Paranaguá - Sur, Brasil. Fueron distribuidos cuatro transectos en paralelo a la playa entre profundidades de 0,5 a 2m, y el número de organismos se contaron en un área de 4 m-2. Después, 164 equinoideos se midieron aleatoriamente (ejes longitudinales y transversales en la vista oral) y la cantidad de simbiontes por anfitrión fue contada. Observamos 906 especímenes de E. emarginata (558 en septiembre / 11 y 348 en mayo / 12), las densidades de equinoideos van de cero a 20 ind.4m-2. Los equinoideos siguieron un patrón de distribución agrupado con manchas de diferentes densidades dentro de los transectos y puntos (F2, 15 = 9.466, p < 0.01). En septiembre / 11 fueron observadas manchas más cerca de la costa en comparación con mayo / 12. El simbionte D. crinitichelis muestra un patrón de distribución más variable cuando se compara con sus anfitriones. En septiembre / 11 los cangrejos eran agrupados, así como los equinoideos. Mientras en mayo / 12 D. crinitichelis se distribuyeron al azar, mostrando un patrón distinto de que los observados para E. emarginata. No se observó relación entre el tamaño de E. emarginata y el número de simbiontes (eje longitudinal: r = - 0.021, p < 0.05; eje transversal: r = - 0.017, p > 0.05), rechazando la hipótesis de que espacio es un recurso limitante para los cangrejos. Al contrario, los patrones de distribución de D. crinitichelis fueron aparentemente influenciados por la distribución de la población de los anfitriones, en lugar de por un solo espécimen. Esto sugiere que otros factores (por ejemplo, la distribución espacial y la conectividad entre manchas en las poblaciones de equinoideos) pueden ser más importantes para la dinámica poblacional de D. crinitichelis de que la competición por espacio en sí.

Benthic Habitat Quality Assessment in Estuarine Intertidal Flats Based on Long-Term Data with Focus on Responses to Eco-Restoration Activity

A long-term assessment of the benthic habitat quality of intertidal flats in Liaohe Estuary was conducted by three integrating ecological indices, AZTI’s Marine Biotic Index (AMBI), Multivariate-AMBI (M-AMBI), and Shannon–Wiener diversity index (H′) based on macrobenthos data from 2013 to 2020. The results showed that the macrobenthic communities were characterized by indifferent and sensitive species of AMBI ecological groups. The annual ranges of H′, AMBI, and M-AMBI were 0.77–1.56, 1.44–3.73 and 0.36–0.54, respectively. Noticeable differences were found among assessment obtained by these biotic indices. Approximately 100%, 24%, and 78% sampling sites had “moderate”, “poor”, and “bad” statuses as assessed by H′, AMBI, and M-AMBI, respectively. Compared with H′ and AMBI, M-AMBI may be more applicable to evaluate the benthic habitat quality of intertidal flats in Liaohe Estuary. Results suggest that the benthic habitat quality in the middle parts of intertidal flats still had an unacceptable status and has not improved radically to date after large-scale “mariculture ponds restored to intertidal flats”

Ecological network analysis of traits reveals variable response capacity to stress

Response diversity increases the potential 'options' for ecological communities to respond to stress (i.e. response capacity). An indicator of community response diversity is the diversity of different traits associated with their capacity to be resistant to stress, to recover and to regulate ecosystem functions. We conducted a network analysis of traits using benthic macroinvertebrate community data from a large-scale field experiment to explore the loss of response diversity along environmental gradients. We elevated sediment nutrient concentrations (a process that occurs with eutrophication) at 24 sites (in 15 estuaries) with varying environmental conditions (water column turbidity and sediment properties). Macroinvertebrate community response capacity to nutrient stress was dependent on the baseline trait network complexity in the ambient community (i.e. non-enriched sediments). The greater the complexity of the baseline network, the less variable the network response to nutrient stress was; in contrast, more variable responses to nutrient stress occurred with simpler networks. Thus, stressors or environmental variables that shift baseline network complexity also shift the capacity for these ecosystems to respond to additional stressors. Empirical studies that explore the mechanisms responsible for loss of resilience are essential to inform our ability to predict changes in ecological states.Peer reviewe

Supplementary material for: Ecological network analysis of traits reveals variable response capacity to stress

The supplementary material contains extra methodological detail and results to complement the pape