Island Biogeography in the Anthropocene and Quaternary

The realization that human activities have a major influence on ecosystems from local to global scales has given rise to the concept of the Anthropocene. However, although the influence of human activities on biodiversity is clearly significant, it remains unclear to what extent the rate and magnitude of biodiversity changes differ from pre-human dynamics. Islands are ideal model systems for understanding the relative contribution of environmental and societal variables to biodiversity change because the onset of human activities on islands can generally be clearly defined. The aim of this PhD thesis is to place human-environment interactions on islands in the context of environmental fluctuations over the Quaternary. The thesis consists of two parts. First, I quantify how island area and isolation have changed over the Quaternary as a result of climate-driven sea-level fluctuations, and analyse how these dynamics have shaped modern biodiversity patterns. Secondly, I study how human activities in the past and present have shaped island ecosystems and landscapes, and compare their rate and magnitude to pre-human dynamics. Overall, the findings of my thesis indicate that modern biodiversity patterns show legacies of past human activities but are also imprinted by environmental dynamics in deep-time. Furthermore, the rate of change following human settlement on islands can largely exceed Quaternary background rates. Therefore, my findings are in line with studies that indicate that human activities have become a major driver in shaping biodiversity across scales. Nonetheless, my comparison of islands worldwide also highlights the diverse ways in which abiotic, biotic, and anthropogenic variables have interacted across individual islands. Therefore, future studies should acknowledge that global biodiversity change can manifest differently across localities. Finally, I emphasize the importance of strengthening interdisciplinary approaches in island biogeography to enhance our understanding of biodiversity changes in the Anthropocene, and how they relate to deeptime dynamics.A constatação de que as atividades humanas exercem uma grande influência sobre os ecossistemas, da escala local à global, originou o conceito do Antropoceno. No entanto, apesar da influência das atividades humanas ser claramente significativa, ainda não está claro até que ponto a taxa e magnitude de alterações na biodiversidade diferem da dinâmica pré-humana. As ilhas constituem sistemas modelo ideais para compreender a contribuição relativa de variáveis ambientais e sociais, porque o início das atividades humanas é em geral conhecido. O objetivo desta tese de doutoramento é enquadrar as interações homem-ambiente nas ilhas no contexto das flutuações ambientais no Quaternário. A tese consiste em duas partes. Primeiro, quantifico como a área da ilha e o isolamento mudaram no Quaternário devido às flutuações do nível do mar provocadas pelo clima e analiso como essas dinâmicas moldaram os padrões modernos de biodiversidade. Em segundo lugar, estudo como as atividades humanas passadas e presentes moldaram os ecossistemas e paisagens das ilhas e comparo a sua taxa e magnitude com a dinâmica pré-humana. As conclusões de minha tese indicam que os padrões modernos de biodiversidade mostram legados de atividades humanas passadas, mas também são afectados pela dinâmica ambiental em escalas temporais longinquas. Além disso, a taxa de alterações após o povoamento humano nas ilhas pode exceder largamente taxas quaternárias antecedentes. Os meus resultados concordam com estudos mostrando que as atividades humanas têm sido um fator importante na modelação da biodiversidade ao longo do tempo. Mas a minha comparação global de ilhas também destaca diversas maneiras pelas quais variáveis abióticas, bióticas e antropogénicas interagiram entre ilhas. Estudos futuros devem reconhecer que a mudança global da biodiversidade pode manifestarse de formas diferente entre localidades. Por fim, destaco a importância de aumentar abordagens interdisciplinares na biogeografia insular para melhor compreender as mudanças da biodiversidade no Antropoceno

Glottospace: R package for language mapping and geospatial analysis of linguistic and cultural data

The glottospace R package facilitates the geospatial analysis of linguistic and cultural data. The aim of the package is to provide a streamlined workflow for geolinguistic analysis, including data entry, data import, cleaning, exploration, language mapping and visualisation, and export. Glottospace is also intended as an R interface to global linguistic and cultural databases such as Glottolog, WALS, and D-PLACE, contributing to improved reproducibility of data analysis

Modelling sea level driven change of Macaronesian archipelago configurations since 120 kyr BP

The MacArthur and Wilson island biogeography theory relates species diversity on islands as the result of equilibrium between extinctions and colonization events which rates depend on island size and isolation. Although island size and isolation can be considered static on ecological timescales (<100 years) they are not static on longer time scales. Since the last million years sea levels fluctuate with a period of ca. 120 kyr between -120 m and up to +10 m MSL (Mean Sea Level). Due to these sea level changes islands have changed in size and ultimately may have drowned or emerged. The rate and degree of their drowning depends on island morphometry and the shape of the sea level change curve. We explore the effects of global sea level cycles on the configuration of archipelagos and volcanic islands of Macaronesia. The results indicate that the islands changed shape considerably during the last 120 kyr. Notably the period between 80 kyr and 15 kyr ago sea levels were at least 80 m lower than present and several islands now isolated were merged or were much larger than present. Recent shrinking of islands due to the sea level rise since the last glacial maximum period (20 kyr BP) led to more than 50% reductions in island size, significant loss of coastal habitat and a significant increase in isolation by the increase of distances between islands and island and continents. Island size reduction must have induced pressures especially on terrestrial insular ecosystems, inducing upward migrations and interspecies competitions, and probable extinctions. The splitting of merged islands must have led to separations of populations leading to gene flow losses for some biota. Present day islands are not representative for the mean island configurations during the last Myr but rather represent an anomaly. Islands at present are smallest and most isolated and this configuration makes the insular biota even more vulnerable to human impact

The social lives of isolates (and small language families):The case of the Northwest Amazon

The Americas are home to patches of extraordinary linguistic (genealogical) diversity. These high-diversity areas are particularly unexpected given the recent population of the Americas. In this paper, we zoom in on one such area, the Northwest Amazon, and address the question of how the diversity in this area has persisted to the present. We contrast two hypotheses that claim opposite mechanisms for the maintenance of diversity: the isolation hypothesis suggests that isolation facilitates the preservation of diversity, while the integration hypothesis proposes that conscious identity preservation in combination with contact drives diversity maintenance. We test predictions for both hypotheses across four disciplines: biogeography, cultural anthropology, population genetics and linguistics. Our results show signs of both isolation and integration, but they mainly suggest considerable diversity in how groups of speakers have interacted with their surroundings

Interpreting mismatches between linguistic and genetic patterns among speakers of Tanimuka (Eastern Tukanoan) and Yukuna (Arawakan)

Northwestern Amazonia is home to a great degree of linguistic diversity, and the human societies in that region are part of complex networks of interaction that predate the arrival of Europeans. This study investigates the population and language contact dynamics between two languages found within this region, Yukuna and Tanimuka, which belong to the Arawakan and Tukanoan language families, respectively. We use evidence from linguistics, ethnohistory, ethnography and population genetics to provide new insights into the contact dynamics between these and other human groups in NWA. Our results show that the interaction between these groups intensified in the last 500 years, to the point that it is difficult to differentiate between them genetically. However, this close interaction has led to more substantial contact-induced language changes in Tanimuka than in Yukuna, consistent with a scenario of language shift and asymmetrical power relations

Global raster dataset on historical coastline positions and shelf sea extents since the Last Glacial Maximum

Motivation: Historical changes in sea level caused shifting coastlines that affected the distribution and evolution of marine and terrestrial biota. At the onset of the Last Glacial Maximum (LGM) 26 ka, sea levels were >130 m lower than at present, resulting in seaward-shifted coastlines and shallow shelf seas, with emerging land bridges leading to the isolation of marine biota and the connection of land-bridge islands to the continents. At the end of the last ice age, sea levels started to rise at unprecedented rates, leading to coastal retreat, drowning of land bridges and contraction of island areas. Although a growing number of studies take historical coastline dynamics into consideration, they are mostly based on past global sea-level stands and present-day water depths and neglect the influence of global geophysical changes on historical coastline positions. Here, we present a novel geophysically corrected global historical coastline position raster for the period from 26 ka to the present. This coastline raster allows, for the first time, calculation of global and regional coastline retreat rates and land loss rates. Additionally, we produced, per time step, 53 shelf sea rasters to present shelf sea positions and to calculate the shelf sea expansion rates. These metrics are essential to assess the role of isolation and connectivity in shaping marine and insular biodiversity patterns and evolutionary signatures within species and species assemblages. Main types of variables contained: The coastline age raster contains cells with ages in thousands of years before present (bp), representing the time since the coastline was positioned in the raster cells, for the period between 26 ka and the present. A total of 53 shelf sea rasters (sea levels <140 m) are presented, showing the extent of land (1), shelf sea (0) and deep sea (NULL) per time step of 0.5 kyr from 26 ka to the present. Spatial location and grain: The coastline age raster and shelf sea rasters have a global representation. The spatial resolution is scaled to 120 arcsec (0.333° × 0.333°), implying cells of c. 3,704 m around the equator, 3,207 m around the tropics (±30°) and 1,853 m in the temperate zone (±60°). Time period and temporal resolution: The coastline age raster shows the age of coastline positions since the onset of the LGM 26 ka, with time steps of 0.5 kyr. The 53 shelf sea rasters show, for each time step of 0.5 kyr, the position of the shelf seas (seas shallower than 140 m) and the extent of land. Level of measurement: Both the coastline age raster and the 53 shelf sea rasters are provided as TIFF files with spatial reference system WGS84 (SRID 4326). The values of the coastline age raster per grid cell correspond to the most recent coastline position (in steps of 0.5 kyr). Values range from 0 (0 ka, i.e., present day) to 260 (26 ka) in bins of 5 (0.5 kyr). A value of “no data” is ascribed to pixels that have remained below sea level since 26 ka. Software format: All data processing was done using the R programming language

The social lives of isolates (and small language families): the case of the Northwest Amazon

The Americas are home to patches of extraordinary linguistic (genealogical) diversity. These high-diversity areas are particularly unexpected given the recent population of the Americas. In this paper, we zoom in on one such area, the Northwest Amazon, and address the question of how the diversity in this area has persisted to the present. We contrast two hypotheses that claim opposite mechanisms for the maintenance of diversity: the isolation hypothesis suggests that isolation facilitates the preservation of diversity, while the integration hypothesis proposes that conscious identity preservation in combination with contact drives diversity maintenance. We test predictions for both hypotheses across four disciplines: biogeography, cultural anthropology, population genetics and linguistics. Our results show signs of both isolation and integration, but they mainly suggest considerable diversity in how groups of speakers have interacted with their surroundings

Recent geospatial dynamics of Terceira (Azores, Portugal) and the theoretical implications for the biogeography of active volcanic islands

Ongoing work shows that species richness patterns on volcanic oceanic islands are shaped by surface area changes driven by longer time scale (>1 ka) geological processes and natural sea level fluctuations. A key question is: what are the rates and magnitudes of the forces driving spatial changes on volcanic oceanic islands which in turn affect evolutionary and biogeographic processes? We quantified the rates of surface-area changes of a whole island resulting from both volcanogenic flows and sea level change over the last glacial-interglacial (GI) cycle (120 ka) for the volcanically active island of Terceira, (Azores, Macaronesia, Portugal). Volcanogenic activity led to incidental but long-lasting surface area expansions by the formation of a new volcanic cone and lava-deltas, whereas sea level changes led to both contractions and expansions of area. The total surface area of Terceira decreased by as much as 24% per time step due to changing sea levels and increased by 37% per time step due to volcanism per time step of 10 ka. However, while sea levels nearly continuously changed the total surface area, volcanic activity only impacted total surface area during two time steps over the past 120 ka. The surface area of the coastal and lowland region (here defined as area <300 m) was affected by sea level change (average change of 11% / 10 ka for 120–0 ka) and intra-volcanic change (average change of 17% / 10 ka for 120–0 ka). We discuss the biogeographic implications of the quantified dynamics, and we argue that surface area change is mainly driven by volcanic processes in the early stages of the island’s life cycle, while during the later stages, area change becomes increasingly affected by sea level dynamics. Both environmental processes may therefore affect biota differently during the life cycle of volcanic oceanic islands.S.J.N. received funding from the Portuguese National Funds, through Fundação para a Ciência e a Tecnologia (FCT), within the project UID/BIA/00329/2013 and the Research Fellowship PD/BD/114380/2016. S.P.A. acknowledges his research contract (IF/00465/2015) funded by the Portuguese Science Foundation (FCT). C.S.M. is benefiting from a PhD grant M3.1.a/F/100/2015 from FRCT/Açores 2020 by Fundo Regional para a Ciência e Tecnologia (FRCT). Financial support to R.A. was received from the Laboratory of Excellence ‘TULIP’ (PIA-10-LABX-41). This work was supported by FEDER funds through the Operational Programme for Competitiveness Factors – COMPETE and by National Funds through FCT under the UID/BIA/50027/2013, POCI-01-0145-FEDER-006821 and under DRCT-M1.1.a/005/Funcionamento-C-/2016 (CIBIO-A) project from FRCT. This work was also supported by FEDER funds (in 85%) and by funds of the Regional Government of the Azores (15%) through Programa Operacional Açores 2020, in the scope of the project “AZORESBIOPORTAL – PORBIOTA”: ACORES‑01‑0145-FEDER-000072.info:eu-repo/semantics/publishedVersio

Interpreting mismatches between linguistic and genetic patterns among speakers of Tanimuka (Eastern Tukanoan) and Yukuna (Arawakan)

Northwestern Amazonia is home to a great degree of linguistic diversity, and the human societies in that region are part of complex networks of interaction that predate the arrival of Europeans. This study investigates the population and language contact dynamics between two languages found within this region, Yukuna and Tanimuka, which belong to the Arawakan and Tukanoan language families, respectively. We use evidence from linguistics, ethnohistory, ethnography and population genetics to provide new insights into the contact dynamics between these and other human groups in NWA. Our results show that the interaction between these groups intensified in the last 500 years, to the point that it is difficult to differentiate between them genetically. However, this close interaction has led to more substantial contact-induced language changes in Tanimuka than in Yukuna, consistent with a scenario of language shift and asymmetrical power relations

Global raster dataset on historical coastline positions and shelf sea extents since the Last Glacial Maximum

Abstract Motivation Historical changes in sea level caused shifting coastlines that affected the distribution and evolution of marine and terrestrial biota. At the onset of the Last Glacial Maximum (LGM) 26 ka, sea levels were >130?m lower than at present, resulting in seaward-shifted coastlines and shallow shelf seas, with emerging land bridges leading to the isolation of marine biota and the connection of land-bridge islands to the continents. At the end of the last ice age, sea levels started to rise at unprecedented rates, leading to coastal retreat, drowning of land bridges and contraction of island areas. Although a growing number of studies take historical coastline dynamics into consideration, they are mostly based on past global sea-level stands and present-day water depths and neglect the influence of global geophysical changes on historical coastline positions. Here, we present a novel geophysically corrected global historical coastline position raster for the period from 26 ka to the present. This coastline raster allows, for the first time, calculation of global and regional coastline retreat rates and land loss rates. Additionally, we produced, per time step, 53 shelf sea rasters to present shelf sea positions and to calculate the shelf sea expansion rates. These metrics are essential to assess the role of isolation and connectivity in shaping marine and insular biodiversity patterns and evolutionary signatures within species and species assemblages. Main types of variables contained The coastline age raster contains cells with ages in thousands of years before present (bp), representing the time since the coastline was positioned in the raster cells, for the period between 26 ka and the present. A total of 53 shelf sea rasters (sea level