Sandra Nogué’s research while affiliated with Autonomous University of Barcelona and other places
What is this page?
This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.
Global warming significantly alters lake ecosystems worldwide. However, the effects of warming at a regional scale are often overlooked due to the scarcity of multidecadal to centennial regional studies. Here, we examined diatom sedimentary records from five lakes on São Miguel Island (Azores archipelago) over the last 170 years. Our analysis using hierarchical generalised additive models revealed an abrupt shift in the island-wide diatom community around 1982 CE, when the Northern Hemisphere temperature exceeded 0.35 °C above the 20th-century mean. This community regime shift resulted in a 27% loss in regional diatom diversity across the Island. Furthermore, previous anthropogenic impacts may have enhanced lakes’ rapid response to warming. These findings highlight the vulnerability of freshwater island ecosystems to climate warming and emphasise the importance of transitioning from local to regional assessments to preserve regional resilience and prevent irreversible damage to these essential freshwater resources and their biodiversity.
This is a book on the thermophilous woodlands of Macaronesia (Canary Islands, Madeira, and Cape Verde), which covers all the different communities and types of this vegetation and explains their biodiversity, composition, general characteristics, etc.
The Gulf of Guinea Islands (Fig. 1) present diverse natural and historical contexts but remain a blind spot in archaeological and paleoenvironmental research. Written documents starting in the 15th century describe the landscapes encountered by Europeans, but rarely mention the deep changes caused by such encounters. The earliest and most detailed account of São Tomé and its settlement, for example, comes from the mid-16th century and describes an island covered by a thick forest of unfamiliar tree species that “seemed to touch the sky” and how Europeans cut and burned trees and vegetation to make way for a town and sugar plantations (Loureiro 1989: 29). This account is a small window into human impacts driven by colonial encounters; however, prior to the initiation of our research efforts, one could only speculate about the full scope of environmental changes in the Gulf of Guinea Islands. Our research highlights the potential of multi-disciplinary collaborations - in this case, integrating archaeological and paleoenvironmental (coring-based) research - to shed light on changes through time, generate new data, and bring this area to the attention of the scientific community, while fostering local participation through capacity-building.
Controversies exist regarding the extent of past human influence on terrestrial ecosystems and the relative importance of human versus climatic factors in shaping Holocene vegetation. However, there has been no systematic examination of these issues at a global scale.
Here we integrate palaeoecological, archaeological, and palaeoclimate data to assess the influence of humans and climate in driving patterns of past vegetation during the early and middle Holocene (8500 - 2000 years before present) as recorded by pollen-assemblage properties. We quantify and summarise the patterns of change in different properties from individual records to a global scale and assess the relative importance of humans and/or climate in influencing them. Additionally, we assess whether the internal relationships among these properties changed through time.
While we find evidence that humans have high localized impact on vegetation dynamics in various regions and times periods, when considered globally, humans appear to be a secondary factor, during the early-to-mid Holocene. Our results underscore the value of merging multidisciplinary palaeodata to provide a holistic understanding of millennia-spanning relationships between humans, climate, and vegetation across different spatial scales.
Sedimentary records covering the Late Pleistocene show glacial-interglacial and millennial temperature changes accompanied with, for instance, rainfall and vegetation changes at the global and regional scales. However, such records are missing for the islands of Macaronesia. Here we generate three sedimentary records over the last 10,000 to 45,000 years from the islands of Tenerife, Gran Canaria, and La Gomera using glycerol dialkyl glycerol tetraethers (GDGTs). At the global scale, air temperature and soil pH influence GDGT distributions in soils, although these biomarkers also react to other environmental factors (e.g., land use, vegetation, and soil moisture and chemistry) and shifts in bacterial and archaeal communities. Accordingly, we examined several GDGT-based proxies, notably those using bacterial branched GDGTs (brGDGTs), to assess their applicability in the Canary Islands. Our preliminary results show drastic downcore and inter-site changes in GDGT distributions, with brGDGT-based air temperature ranges larger than 10°C over the last 10,000 to 45,000 years when applying global calibrations at the three study sites. Air temperatures and soil pH inferred from brGDGTs decrease in Tenerife and La Gomera over the end of the African Humid Period, which suggests an effect of reduced rainfall on brGDGTs, possibly accompanied with a shift in bacterial communities. Air temperatures inferred from brGDGTs show a general increase over the last 27,000 years in Gran Canaria, whereas cyclization and isomerization indices of brGDGTs suggest typically opposite changes in soil pH, in disagreement with global-scale patterns from surficial soils. Our GDGT-based records also show a few drastic increases in archaeal GDGT abundances relative to the full GDGT pool after the Last Glacial Maximum, notably in Gran Canaria and La Gomera, partly related to the rainfall increase during the African Humid Period.
A minuscule fraction of the Earth's paleobiological diversity is preserved in the geological record as fossils. What plant remnants have withstood taphonomic filtering, fragmentation, and alteration in their journey to become part of the fossil record provide unique information on how plants functioned in paleo‐ecosystems through their traits. Plant traits are measurable morphological, anatomical, physiological, biochemical, or phenological characteristics that potentially affect their environment and fitness. Here, we review the rich literature of paleobotany, through the lens of contemporary trait‐based ecology, to evaluate which well‐established extant plant traits hold the greatest promise for application to fossils. In particular, we focus on fossil plant functional traits, those measurable properties of leaf, stem, reproductive, or whole plant fossils that offer insights into the functioning of the plant when alive. The limitations of a trait‐based approach in paleobotany are considerable. However, in our critical assessment of over 30 extant traits we present an initial, semi‐quantitative ranking of 26 paleo‐functional traits based on taphonomic and methodological criteria on the potential of those traits to impact Earth system processes, and for that impact to be quantifiable. We demonstrate how valuable inferences on paleo‐ecosystem processes (pollination biology, herbivory), past nutrient cycles, paleobiogeography, paleo‐demography (life history), and Earth system history can be derived through the application of paleo‐functional traits to fossil plants.
The increasing similarity of plant species composition among distinct areas is leading to the homogenization of ecosystems globally. Human actions such as ecosystem modification, the introduction of non-native plant species and the extinction or extirpation of endemic and native plant species are considered the main drivers of this trend. However, little is known about when floristic homogenization began or about pre-human patterns of floristic similarity. Here we investigate vegetation trends during the past 5,000 years across the tropical, sub-tropical and warm temperate South Pacific using fossil pollen records from 15 sites on 13 islands within the biogeographical realm of Oceania. The site comparisons show that floristic homogenization has increased over the past 5,000 years. Pairwise Bray–Curtis similarity results also show that when two islands were settled by people in a given time interval, their floristic similarity is greater than when one or neither of the islands were settled. Importantly, higher elevation sites, which are less likely to have experienced human impacts, tended to show less floristic homogenization. While biotic homogenization is often referred to as a contemporary issue, we have identified a much earlier trend, likely driven by human colonization of the islands and subsequent impacts.
São Tomé (Gulf of Guinea, Central Africa) is a 854 km2 tropical island that had a pivotal role in early European colonial expansion through the Atlantic between the 15th and 16th centuries. Historical sources suggest that native vegetation has been heavily impacted since human arrival (1470 CE) due to monoculture economies and the introduction of mammals and plants, some of which now have established wild populations. The Afromontane forest of São Tomé, located above 800 m.a.sl., is particularly rich in endemic plant species and has remained relatively unaffected by direct human impacts. Here, we explore how environmental change influenced this forest through the study of a sedimentary sequence from the volcanic crater of Lagoa Amélia (1340 m a.s.l.), a palustrine system located at the boundary between submontane (800–1400 m a.s.l.) and mist forest (above 1400 m a.s.l.). We used fossil pollen, non-pollen palynomorphs, sedimentology and charcoal to determine forest dynamics from the Late Pleistocene to the present. From 14,000 to 12,500 cal yr BP the forest was dominated by taxa from higher altitudes, adapted to cooler and drier climates (e.g. Afrocarpus mannii trees and Psychotria nubicola). After 12,500 cal yr BP, a potential uphill migration was identified by an increase in taxa like the trees Symphonia globulifera and Craterispermum cerinanthum. From 11,200 cal yr BP through the rest of the Holocene taxa from lower altitudes became dominant (e.g. Prunus africana, Polyscias, and Sabicea), except at c. 8500 cal yr BP when rapid cooling led to forest opening. Charcoal showed that fires were frequent during the Late Pleistocene (14,000 to 11,200 cal yr BP), becoming rare during the Holocene until anthropogenic fires started at c. 220 cal yr BP. Other recent anthropogenic impacts detected in Lagoa Amélia included the appearance of pollen of introduced plant species (e.g., Cestrum), and the increase in pollen of economically important species (Elaeis guineensis, Zea mays) and in fungal spores related to introduced herbivores. Our results reveal that climate changed the altitudinal distribution of the Afromontane forest in São Tomé during the Late Pleistocene, as observed on the African continent, and that this ecosystem was also strongly impacted by human arrival, through fire, farming, and introduced species.
... One question that arises from the widespread occurrence of wildfire through the Carboniferous is to what extent has this affected the evolution of plant traits to cope with wildfire (other aspects such as atmospheric compositionsee Beerling et al. (1998) and climate have been consideredsee Boyce and Lee, 2017;Clark et al., 2023;Fluck et al., 2007;Matthaeus et al., 2023;McElwain et al., 2024). Such a topic is more easily considered in Cretaceous and later plants where we have some clues from modern plants and from molecular data (He et al., 2016). ...
... This is separate from the IPPD, but related, and contains many of the same sites, though with a focus on pre-European samples. Examples of other important work in this region that used their own pollen sample compilations include a floristic diversity study of South Pacific islands (Strandberg et al., 2024) and a study of human impact on the biodiversity of islands (Nogué et al., 2021). ...
... Around 4,000 cal BP, the relative sea-level (RSL) in the region was higher than the present state resulting in a different mangrove forest area of occupancy. Analysis of organic matter beneath mangrove stands in New With similar scenarios of sea-level change in the province, high soil carbon sequestration is expected in mangrove ecosystems on other islands such as Tonga or Vanuatu after their seaward migration or reestablishment (Ellison, 2006, Combettes et al., 2015, Strandberg et al., 2023. Despite variations in structural complexity and carbon stocks among mangrove sites in Fiji, all assessed areas were significant carbon reservoirs, with carbon storage corresponding to 73% of carbon stock of the archipelago, while representing only 7% of total forest area (Cameron et al., 2021b). ...
... Mankind has been well aware of climate change in the last decades, due to atmosphere temperature increase caused by combustion gasses. The situation is so severe, it has been started to be called a climate catastrophe [1][2][3][4]. Consequently, humanity is impelled to reduce, or even halt, its green-house gases emission without delay, to circumvent an exacerbation of this climate catastrophe [1][2][3][4]. Concomitantly, the humanity's power consumption has been forewarned to increase to 30 TW by year 2050 [5,6]. ...
... In oceanic islands, intensification of traditional land uses [2,3] and the growing expansion of human activities into the coastal areas originate habitat loss, changes in vegetation structure and the fragmentation of endemic plant populations [4], leading to biodiversity loss, plant extinctions [5,6] and to decreases in abundance and diversity [7]. Among these threats, the proliferation of non-indigenous taxa [8], biological invasions [4,7], and climate change are paramount. ...
... Pairwise comparisons in which neither site or one site or island was settled show that similarity was relatively low (Fig. 3b). Dynamics in pre-human settlement composition are likely related to natural drivers such as sea level change, hydroseral development of wetlands and lacustrine vegetation, volcanism and other disturbances (for example, cyclones and droughts) [34][35][36][37] . These drivers may have an impact on biotic similarity in numerous biotas and habitats as they can affect a given species and thus alter the species pool in similar ways across different communities (for example, ref. 38). ...
... A high frequency and abundance of both natural and human-induced fires has occurred in southern Africa throughout the entire Holocene (Davies et al., 2022;Power et al., 2008), while no natural occurrence of fires on the Kerguelen Island is known in this same period. Local fires could possibly have been ignited by lightning or volcanic activity (Castilla-Beltrán et al., 2023) from the volcanic complexes in the southwest of the Kerguelen Islands (Gautier et al., 1990). However, the vegetation on the island provides relatively little fuel for burning and the oftentimes patchy vegetation cover could prevent fires from spreading over large areas. ...
... The microscopic size of pollen and spores and their low taxonomic resolution create a challenge to their incorporation as functional traits into global trait analysis. However, potential methodologies have been proposed (reviewed in Reitalu & Nogué, 2023; Table 1). Taphonomic biases in the pollen and spore record are very well constrained compared with other fossilized plant parts, and there is a high likelihood of their fossilization. ...
... These proxies, however, come with various biases. First, many plants are insect pollinated, and their pollen production and dispersal are low (de Nascimento et al. 2015;Nogué et al. 2022). Second, the persistent northeasterly trade winds blowing in these latitudes may carry pollen to the islands from ecosystems on the mainland of the Maghreb, Sahara or the Iberian Peninsula, so that the pollen detected on the Canary Islands may include some extraregional components (Hooghiemstra et al. 2006). ...
... The Madeira laurel pigeon is a close relative of the Bolle's pigeon and is largely confined to Madeira's relict forests or laurisilva on the island of Madeira; it was formerly found on the nearby island of Porto Santo (Cartwright, 2019;Florencio et al., 2021). ...
