Papers by Vitor Gonçalves
This dataset presents the distribution of freshwater macroinvertebrates in Madeira Island streams.
20th Congress of the International Union for Quaternary Research (INQUA) in Dublin, Ireland, 25-3... more 20th Congress of the International Union for Quaternary Research (INQUA) in Dublin, Ireland, 25-31 July 2019
Marine and Freshwater Research, 2018
It has been widely reported that shredders play an important role in leaf decomposition, especial... more It has been widely reported that shredders play an important role in leaf decomposition, especially in continental temperate streams. However, the paucity of shredders in many oceanic island streams leads to a greater contribution of microbes to litter decomposition in these streams. In this study, we investigated the importance of shredder presence and density (three levels) and leaf litter identity (Alnus glutinosa, Clethra arborea and Acacia melanoxylon) on leaf litter decomposition in one stream located in the Azores Archipelago. Coarse and fine mesh bags were used to allow natural colonisation of leaf litter by benthic macroinvertebrates or to exclude macroinvertebrates respectively. Treatments with one and three shredders were accomplished by enclosing one or three shredders in the fine mesh bags. Rates of litter decomposition differed significantly among shredder density treatments only for A. glutinosa and C. arborea. Decomposition rates were significantly faster for the nat...
Global and Planetary Change, 2017
The location of the Azores Archipelago in the North Atlantic makes this group of islands an excel... more The location of the Azores Archipelago in the North Atlantic makes this group of islands an excellent setting to study the long-term behavior of large oceanic and atmospheric climate dynamic patterns, such as the Atlantic Multidecadal Oscillation (AMO) and the North Atlantic Oscillation (NAO). Here, we present the impacts of these patterns on Lake Empadadas (Azores Archipelago) from the Medieval Climate Anomaly (MCA)-Little Ice Age (LIA) transition to the present based on sedimentological, geochemical and biological characterizations of the sedimentary record. Multivariate analyses of a number of proxies including X-ray fluorescence (XRF), X-ray diffraction (XRD), total organic and inorganic carbon (TOC and TIC) and diatom life forms abundance reveal that the sedimentary infill evolution has been controlled by (i) fluctuations in the lake level and (ii) variations in organic matter accumulation. Both processes are governed by climate variability and modulated by anthropogenic activities associated with changes on the lake catchment. Changes in these two sedimentary processes have been used to infer five stages: (i) the MCA-LIA transition (ca. 1350-1450 AD) was characterized by a predominantly positive AMO phase, which led to intermediate lake levels and high organic matter concentration; (ii) the first half of the LIA (ca. 1450-1600 AD) was characterized by predominant lowstand conditions and intermediate organic matter deposition mainly related to negative AMO phases; (iii) the second half of the LIA (ca. 1600-1850 AD) was characterized by negative AMO and NAO phases, implying intermediate lake levels and high organic matter deposition; (iv) the Industrial era (ca. 1850-1980 AD) was characterized by the lowest lake level and organic matter accumulation associated with negative AMO phases; and (v) the period spanning between 1980 AD and the present reveals the highest lake levels and low organic matter deposition, being associated with very positive AMO conditions. At decadal-to-centennial scales, the influence of the AMO on Azorean climate plays a larger role than previously thought. In fact, the AMO appears to exert a stronger influence compared to the NAO, which is the main mode of climate variability at shorter time scales.
Journal of phycology, Apr 18, 2016
The family Cymatosiraceae, composed of two subfamilies (Cymatosiroideae and Extubocelluloideae), ... more The family Cymatosiraceae, composed of two subfamilies (Cymatosiroideae and Extubocelluloideae), are elongate, non-pennate diatoms and are commonly reported in marine planktonic and benthic assemblages all over the world. The combination of the gross bilateral symmetry of the frustule and radial symmetry of the valve poration, distinct pore fields at the valve apices and DNA sequence data place this family in the controversial diatom class Mediophyceae, sister to the pennate diatoms. The relationships of the Cymatosiraceae within the Mediophyceae, and the monophyly of the two cymatosiroid subfamilies, have become less stable with the addition of new DNA sequence data. In this paper, we examine 24 cymatosiraceaen strains, including the new taxa Lambertocellus africana (Dąbek & Witkowski) Dąbek, Witkowski & Ashworth comb. nov., Leyanella probus Ashworth, Dąbek & Witkowski sp. nov., and Leyanella pauciporis Ashworth, Dąbek & Park sp. nov. to create the most complete molecular phylogeny...
III International Conference on Island Evolution, Ecology and Conservation - La Reunion 8-13 July
The Azores archipelago is a group of nine oceanic volcanic islands located in the mid-North Atlan... more The Azores archipelago is a group of nine oceanic volcanic islands located in the mid-North Atlantic, roughly 1500 km from Europe and 1900 km from America. In 2018, a sediment core was recovered from Lake Ginjal on Terceira island. A 3.5 m long sediment core was taken using a Russian chamber corer, 0.5 m long, with 5 cm diameter. Lake Ginjal occupies the bottom of a small crater at 390 m above sea level located in the plains of Achada, the oldest volcanic crater of Terceira island. Its maximum length and width are 120 m and 70 m, respectively, and its maximum water depth is 1 m. The core was dated using ¹⁴C and produced a multi-proxy dataset of geochemical and biological analyses that we used to uncover paleoenvironmental changes on Lake Azul in the last 550 years.
Third International Conference on Island Ecology, Evolution and Conservation in University of La ... more Third International Conference on Island Ecology, Evolution and Conservation in University of La Reunion Saint Denis, France, 8-13 July 2019
We investigate the macroecological patterns of the terrestrial biota of the Azorean archipelago, ... more We investigate the macroecological patterns of the terrestrial biota of the Azorean archipelago, namely the species-range size distributions, the distance decay of similarity, and the island species-area relationship (ISAR). We use the most recent up-to-date checklists to describe the diversity at the island level for nine groups (Lichens, Fungi, Diatoms, Bryophytes, Vascular Plants, Nematodes, Molluscs, Arthropods, Vertebrates). The particularities of the Azorean biota result in some differences to the patterns commonly found in other oceanic archipelagos. Strikingly, bryophytes, molluscs and vertebrates show a bimodal species-range size distribution, and vascular plants a right unimodal distribution due the high numbers of widespread species. Such high compositional homogeneity between islands also results in non-significant or even negative decays of similarity with distance among islands for most groups. Dispersal ability, together with other particular characteristics of each taxon, also shapes these distributions, as well as the relationships between island species richness, and area and time. Strikingly, the degree of departure of the richness of the whole archipelago from the SAR of its constituent islands largely depends on the dispersal ability of each group. Comparative studies with other oceanic archipelagos of the globe are however needed to understand the biogeographical and evolutionary processes shaping the remarkably low diversity of the Azorean biota.
Hydrobiologia, 2014
Subfossil biotic assemblages in surface sediments of lakes have been used to infer ecological con... more Subfossil biotic assemblages in surface sediments of lakes have been used to infer ecological conditions across environmental gradients.. Local variables are usually the major drives of assemblage composition, but in remote oceanic islands biogeographic filters may play a significant role. To assess the contribution of local and regional filters in the composition of subfossil diatoms and chironomid assemblages in surface sediments forty-one lakes in Azores archipelago ()were studied and related to environmental variables. Ordination techniques were used to identify the drivers that best explain the composition of these assemblages. Both assemblages are influenced by multiple limnological variables (conductivity, pH, nutrients). However, diatom assemblages differed mainly in the proportion of planktonic versus benthic species along the lakes' depth gradient while Chironomids differed significantly between islands but not between lake depths.. Thus, biogeographic filters play an important role in shaping islands freshwater communities, particularly insect ones, more influenced by geographic variables. Results demonstrate the accuracy and potential of biotic remains in sediments for applied studies of lake ecology, trophic status, climatic trends and ecological reconstruction and evolution of lakes. In the Azores, the application of this information in the development of inference models, is envisaged as further step to accomplish these goals.
The 7th Iberian Congress on Cyanotoxins/3rd Iberoamerican Congress on Cyanotoxins
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Cryptogamie, Algologie, 2020
ABSTRACT Cyanobacteria are diverse, complex and a unique group of microorganisms that inhabit a w... more ABSTRACT Cyanobacteria are diverse, complex and a unique group of microorganisms that inhabit a wide variety of environments. Contrarily to continental areas, studies on cyanobacteria in islands are scarce and need to be reinforced, since climate change impacts are expected to be harsher in islands, due to their geographical isolation and higher exposition to external influences. Here we present a review of the occurrence of cyanobacteria and cyanotoxins in inland and coastal ecosystems in the Atlantic Ocean islands. These microorganisms were reported from diverse habitats, including saline thermal lakes (Iceland), freshwater lakes, terrestrial habitats (Azores, Cuba), and marine coastal areas, either planktonic (Madeira, Canary Islands, Cape Verde) or associated to plants and corals (Brazil, Caribbean Sea). Most of cyanobacteria were reported from freshwaters but some species were found in different habitats. Species richness also varied between islands, with higher number in islands located in temperate regions, and the number of common taxa was low (1-3%). Several toxic species and different types of cyanotoxins were also reported in the Atlantic islands, which are expected to increase with climate change. Mitigation measures should be considered to avoid cyanotoxins risks to environmental and public health. This works shows the great potential of Atlantic islands for cyanobacteria taxonomic, ecological and biogeography research, but more studies are needed with emphasis on less studied islands and habitats and using novel approaches as molecular systematics tools. Furthermore, such studies are of paramount importance for environmental conservation and management strategies, especially facing climate changes.
LEVANTAMENTO BOTANICO NO VLECAO DOS CAPELINHOS l~niversidade dos Aqores, Dept. de Biologia, PT-95... more LEVANTAMENTO BOTANICO NO VLECAO DOS CAPELINHOS l~niversidade dos Aqores, Dept. de Biologia, PT-9500 Ponta Delgada (Aqores}, PORTUGAL. 2~u s w Carlos Machado, Dept. de Hist6ria Natural, PT-9500 Ponta Delgada (Apres), PORTUGAL No irnbito da Expediqgo Cientifica Fait1193, organizada pelo Departamento de Biologia da Universidade dos Aqores, efectuou-se urn levantamento botlnico na drea neo-formada do Complexo Vulcinico dos Capelinhos. Foram registadas vinte e &s espkies vasculares, dezasseis dm quais pertencentes 3 Alian~a Festncion petraeae E. Sjogcen.
Limnologica, 2014
Freshwater communities on remote oceanic islands can be depauperate due to the influence of bioge... more Freshwater communities on remote oceanic islands can be depauperate due to the influence of biogeographic processes that operate over a range of spatial scales, influencing the colonization of organisms, and events that shape local freshwater assemblages. The consequences of this paucity in organism diversity for the functioning of these ecosystems are, however, not well understood. Here, we examine the relative decomposition rate of leaf litter of native vs. exotic origin by aquatic macroinvertebrates and microbial communities in an isolated and depauperate oceanic environment. Bags containing a standard amount of leaf litter of each of 10 tree species (5 native and 5 non-native species) were deployed on two streams. Two types of bags differing in mesh size were used to allow or prevent the access of leaf litter to macroinvertebrates, respectively. Over a period of 28 days, mass loss of leaf litter was similar in the two bag types suggesting that macroinvertebrates had little influence on the break down of leaf litter in this system. In addition, there was no difference in mass loss of leaf litter of native and exotic origin. Decomposition rates were highly species-specific suggesting that decomposition rates were related to inhibitory substance specific of each leaf species. Our results add to the wider literature by showing that in depauperate and isolated ecosystems, and in contrast to temperate continental ecosystems, decomposition of plant litter by aquatic macroinvertebrates is negligible.
Ecosystems, 2011
Lake ecosystems are nowadays often subjected to multi-stressors, such as eutrophication, climate ... more Lake ecosystems are nowadays often subjected to multi-stressors, such as eutrophication, climate change, and fish manipulations, the effects of which can be difficult to disentangle, not least from the usual short-term limnological time-series that are available. However, multi-proxy paleoecological approaches may offer such opportunities, especially in the study of remote island lakes characterized by being species poor and buffered somewhat against the recent climate change. We
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Papers by Vitor Gonçalves