Carina Hoorn

University of Amsterdam | UVA · Ecology and Landscape Dynamics

Amazonia (defined herein as the Amazon basin) is home to the greatest concentration of biodiversity on Earth, providing unique genetic resources and ecological functions that contribute to ecosystem services globally. The lengthy and complex evolutionary history of this region has produced heterogeneous landscapes and riverscapes at multiple scales...

The Amazon is the largest drainage basin on Earth and contains a wide variety of abiotic landscape features. In spite of this, the geodiversity in this basin has not yet been objectively evaluated. We address this knowledge gap by combining a meta-analysis of an existing global geodiversity map and its components with a systematic literature review...

Rapid environmental change, natural resource overconsumption and increasing concerns about ecological sustainability have led to the development of ‘Essential Variables' (EVs). EVs are harmonized data products to inform policy and to enable effective management of natural resources by monitoring global changes. Recent years have seen the instigatio...

The dry continental interior of Asia has remained arid throughout most of its geological history, yet the future of this unique ecosystem remains unclear. Here we use palynological and isotopic records to track vegetation and moisture throughout the warm early Eocene (57 to 44 million years ago) as an analogue for extreme atmospheric CO2 scenarios....

The deformation history of the Eastern Cordillera (EC) and Sub-Andean Zone (SAZ) of southern Peru is critical for understanding the roles that tectonics and climate played in the erosional exhumation of bedrock and the associated sediment flux delivered to the Amazon drainage basin. In this study, we report new field and subsurface data, apatite fi...

South America is home to the highest freshwater fish biodiversity on Earth, and the hotspot of species richness is located in the western Amazon basin. The location of this hotspot is enigmatic, as it is inconsistent with the pattern observed in river systems across the world of increasing species richness towards a river’s mouth. Here we investiga...

The grasses are one of the most diverse plant families on Earth. However, their classification and evolutionary history are obscured by their pollen stenopalynous (similar) morphology. A combination of highresolution imaging of pollen surface ornamentation and computational analysis has previously been proposed as a promising tool to classify grass...

The grasses are one of the most diverse plant families on Earth. However, their classification and evolutionary history are obscured by their pollen stenopalynous (similar) morphology. A combination of high‐resolution imaging of pollen surface ornamentation and computational analysis has previously been proposed as a promising tool to classify gras...

The Amazon hosts one of the largest and richest rainforests in the world, but its origins remain debated. Growing evidence suggests that geodiversity and geological history played essential roles in shaping the Amazonian flora. Here we summarize the geo-climatic history of the Amazon and review paleopalynological records and time-calibrated phyloge...

The debated vegetation response to climate change can be investigated through palynological fossil records from past extreme climate conditions. In this context, the early Eocene (53.3 to 41.2 million years ago (Ma)) is often referred to as a model for a greenhouse Earth. In the Xining Basin, situated on the North-eastern Tibetan Plateau (NETP), th...

The transition from a greenhouse to an icehouse world at the Eocene-Oligocene Transition (EOT) coincided with a large decrease of pollen from the steppe-adapted genus Nitraria. This genus, now common along the Mediterranean coast, Asia and Australia, has a proposed coastal origin and a geographically widespread fossil record. Here we investigated t...

As a crossroads for plant dispersal between Laurasia and Gondwana since at least the late Eocene, the Central Myanmar Basins have yielded rich and diverse fossil pollen . Here we report Grimmipollis burmanica, a new genus and species in the soapberry family (Sapindaceae) from the upper Eocene Yaw Formation in the Central Myanmar Basins. We also inv...

In this Review, we compare rates of anthropogenic and natural environmental changes in the Amazon and South America and in the larger Earth system. We focus on deforestation and carbon cycles because of their critical roles on the Amazon and Earth systems. We found that rates of anthropogenic processes that affect Amazonian ecosystems are up to hun...

The Burma Terrane has yielded some of the earliest pieces of evidence for monsoonal rainfall in the Bay of Bengal. However, Burmese ecosystems and their potential monsoonal imprint remain poorly studied. This study focuses on the late Eocene Yaw Formation (23° N) in central Myanmar, which was located near the equator (c. 5° N) during the Eocene. We...

While the latitudinal diversity gradient has received much attention, biodiversity and species richness also vary between continents across similar latitudes. Fossil information can be used to understand the evolutionary mechanisms that generated such variation between continents of similar latitudes. We integrated fossil data into a phylogenetic a...

Some of the earliest pieces of evidence for monsoonal activity in the Bengal Bay come from the middle and Upper Eocene sedimentary series of Myanmar. Recent paleogeographic reconstructions have yet relocated Myanmar close to the equator during the Eocene, which questions the relevance of Burmese material to study past South Asian monsoonal activity...

Poaceae (the grass family) is highly diverse, geographically widespread, and an important component of many terrestrial ecosystems. Poaceae pollen size has previously been suggested as a proxy to reconstruct the past vegetation and climates in the Amazon area, but it is still unclear if this variable can be used at broader spatial and deep-time sca...

In the nineteenth century, Alexander von Humboldt and Alfred Russel Wallace laid out the basis for the field of biogeography, the discipline that studies the relation between organisms and their geographic distribution. Almost in parallel with the birth of biogeography, the foundations of geology were laid out, providing a dimension of time to spat...

Poaceae (the grasses) originated in the Cretaceous, but started their rise to global dominance in the early Miocene (ca 23–16 Ma), a condition that persists until the present. This family is currently distributed in highly productive grassland ecosystems occupying around 40% of the Earth’s land surface, and with over 11 000 species is one of the mo...

This Report provides a comprehensive, objective, open, transparent, systematic, and rigorous scientific assessment of the state of the Amazon’s ecosystems, current trends, and their implications for the long-term well-being of the region, as well as opportunities and policy relevant options for conservation and sustainable development.

This book aims to view and to understand Alexander von Humboldt from different perspectives and in varying disciplinary contexts. His contributions addressed numerous topics in the earth but also life sciences—spanning from geo-botany, climatology, paleontology, oceanography, mineralogy, resources, and hydrogeology to links between the environmenta...

Science Panel for the Amazon (SPA)/Amazon Assessment Report 2021 The Science Panel for the Amazon is an unprecedented initiative convened under the auspices of the United Nations Sustainable Development Solutions Network (SDSN). The SPA is composed of over 200 preeminent scientists and researchers from the eight Amazonian countries, French Guiana,...

This report on geology and geo diversity of the Amazon belongs to the: Science Panel for the Amazon/Amazon Assessment Report 2021 The Science Panel for the Amazon is an unprecedented initiative convened under the auspices of the United Nations Sustainable Development Solutions Network (SDSN). The SPA is composed of over 200 preeminent scientists a...

In the Miocene, a large wetland system extended from the Andean foothills into western Amazonia. This system has no modern analogue and the driving mechanisms are not yet fully understood. Dynamic topography and Andean uplift are thought to have controlled deposition, with allocyclic base level changes driven by eustasy and orbital forcing also pla...

In the Miocene (23–5 Ma), a large wetland known as the Pebas System characterized western Amazonia. During the Middle Miocene Climatic Optimum (c. 17–15 Ma), this system reached its maximum extent and was episodically connected to the Caribbean Sea, while receiving sediment input from the Andes in the west, and the craton (continental core) in the...

The aim of this Special Issue is to improve understanding of the uplift of the Andes and its far-reaching impact on climate and biodiversity in South America from the late Mesozoic onwards. The Andes form the backbone of the South American continent and are the world's most biodiverse mountain system (Pérez-Escobar et al., in press). This biodivers...

Fossil pollen from dipterocarps show shared floristic heritage between Asia and Africa

The Andes are the world's most biodiverse mountain chain, encompassing a complex array of ecosystems from tropical rainforests to alpine habitats. We provide a synthesis of Andean vascular plant diversity by estimating a list of all species with publicly available records, which we integrate with a phylogenetic dataset of 14 501 Neotropical plant s...

Reference: Lim, J.Y., Huang, H., Farnsworth, A., Lunt, D.J., Baker, W.J., Morley, R.J., Kissling, W.D. & Hoorn, C. (2022) The Cenozoic history of palms: Global diversification, biogeography, and the decline of megathermal forests. Contact: Jun Ying Lim (junyinglim@gmail.com), Huasheng Huang (buxushuang@gmail.com)

The Science Panel for the Amazon (SPA) is an unprecedented initiative convened under the auspices of the United Nations Sustainable Development Solutions Network (SDSN). The SPA is composed of over 200 preeminent scientists and researchers from the eight Amazonian countries, French Guiana, and global partners. These experts came together to debate,...

Aim Megathermal rain forests and mangroves are much smaller in extent today than in the early Cenozoic, primarily owing to global cooling and drying trends since the Eocene–Oligocene transition (c. 34 Ma). The general reduction of these biomes is hypothesized to shape the diversity and biogeographical history of tropical plant clades. However, thi...

This Report provides a comprehensive, objective, open, transparent, systematic, and rigorous scientific assessment of the state of the Amazon’s ecosystems, current trends, and their implications for the long-term well-being of the region, as well as opportunities and policy relevant options for conservation and sustainable development.

This Report provides a comprehensive, objective, open, transparent, systematic, and rigorous scientific assessment of the state of the Amazon’s ecosystems, current trends, and their implications for the long-term well-being of the region, as well as opportunities and policy relevant options for conservation and sustainable development.

Recent studies suggest increasing sensitivity to orbital variations across the Eocene-Oligocene greenhouse to icehouse climate transition. However, climate simulations and paleoenvironmental studies mostly provide snapshots of the past climate, therefore overlooking the role of this short-term variability in driving major environmental changes and...

Palm and palm-like (PPL) taxa have been widely reported at low-mid latitudes in Paleogene pollen assemblages. Yet their occurrence in the Paleogene of Myanmar remains poorly documented. Here we investigate the morphology of PPL pollen along a middle to upper Eocene sedimentary sequence in the Central Myanmar Basin and discuss their nearest living r...

A micrograph (a swamp fern spore 𝙂𝙚𝙢𝙢𝙖𝙩𝙤𝙨𝙥𝙤𝙧𝙞𝙨 𝙜𝙚𝙢𝙢𝙖𝙩𝙤𝙞𝙙𝙚𝙨 with affinity to 𝘾𝙮𝙘𝙡𝙤𝙥𝙝𝙤𝙧𝙪𝙨) in our paper ("𝗔𝘁 𝗮 𝗰𝗿𝗼𝘀𝘀𝗿𝗼𝗮𝗱𝘀: 𝗧𝗵𝗲 𝗹𝗮𝘁𝗲 𝗘𝗼𝗰𝗲𝗻𝗲 𝗳𝗹𝗼𝗿𝗮 𝗼𝗳 𝗰𝗲𝗻𝘁𝗿𝗮𝗹 𝗠𝘆𝗮𝗻𝗺𝗮𝗿 𝗼𝘄𝗲𝘀 𝗶𝘁𝘀 𝗰𝗼𝗺𝗽𝗼𝘀𝗶𝘁𝗶𝗼𝗻 𝘁𝗼 𝗽𝗹𝗮𝘁𝗲 𝗰𝗼𝗹𝗹𝗶𝘀𝗶𝗼𝗻 𝗮𝗻𝗱 𝘁𝗿𝗼𝗽𝗶𝗰𝗮𝗹 𝗰𝗹𝗶𝗺𝗮𝘁𝗲", Huang et al. (2021), https://doi.org/10.1016/j.revpalbo.2021.104441) was selected as the cover image on the cover of volume 2...

South America is home to the highest freshwater fish biodiversity on Earth. The hotspot of species richness is located in the western Amazon Basin, and richness decreases downstream along the Amazon River towards the mouth at the Atlantic coast, which contradicts the positive relationship between stream size and biodiversity that is commonly observ...

Myanmar was shaped by the India–Asia collision, fusion of the Burma Terrane (BT) with Asia, and mountain building. Throughout this process new elevational gradients and habitats were formed, which affected the regional climate, but also forged new dispersal routes into Asia and India. In spite of its importance, the vegetation history of Myanmar is...

The geology of Myanmar was shaped by the India-Asia collision, fusion of the Burma Terrane (BT) with Asia, and mountain building. Throughout this process new elevational gradients and habitats were formed, which affected the regional climate and biodiversity, but also forged new dispersal routes into Asia and India. In spite of its importance, the...

Aim Forest composition and distribution are determined by a myriad of factors, including climate. As models of tropical rain forest, palms are often used as indicator taxa, particularly the Mauritiinae. We question, what characterizes the Mauritiinae pollen in the global fossil record? And when did the Mauritiinae become endemic to South America?...

Supporting Information 1 (Figs. S1-S8 & Appendices S1-S2) for Bogotá-Ángel et al. (2021)

Supporting Information 2 (Tables S1-S5) for Bogotá-Ángel et al. (2021)

Asian mineral dust has been studied extensively for its role in affecting regional‐to global‐scale climate and for its deposits, which enable reconstructing Asian atmospheric circulation in the past. However, the timing and origin of the dust deposits remain debated. Numerous loess records have been reported across the Asian continent with ages var...

Sporopollenin is a highly resistant biopolymer that forms the outer wall of pollen and spores (sporomorphs). Recent research into sporopollenin chemistry has opened up a range of new avenues for palynological research, including chemotaxonomic classification of morphologically cryptic taxa. However, there have been limited attempts to directly inte...

The Amazon drainage basin is extremely biodiverse, yet the origins of this diversification remain much debated. One of the possible drivers of plant diversity are the marine incursions that reached Amazonia during the Miocene and connected western Amazonia with the Caribbean. In the Miocene, large parts of western Amazonia were covered by extensive...

In the Miocene (23–5 Ma), a large wetland known as the Pebas System characterized western Amazonia. During the Middle Miocene Climatic Optimum (c. 17–15 Ma), this system reached its maximum extent and was episodically connected to the Caribbean Sea, while receiving sediment input from the Andes in the west, and the craton (continental core) in the...

The origins and development of the arid and highly seasonal steppe-desert biome in Central Asia, the largest of its kind in the world, remain largely unconstrained by existing records. It is unclear how Cenozoic climatic, geological, and biological forces, acting at diverse spatial and temporal scales, shaped Central Asian ecosystems through time....

Soil respiration (Rs), the production of carbon dioxide in soils, increases dramatically from deserts to forested ecosystems. Rs values thus provide a potential tool to identify past ecosystems if recorded in sedimentary archives. Here, we propose a quantitative method to reconstruct past Rs values from paleosols. This method reverses the soil pale...

In the Palaeogene, pollen assemblages at low and mid latitudes are characterized by abundant palm and palm-like (PPL) taxa. Although these taxa have been widely reported, their occurrence in the Palaeogene of Myanmar remains poorly documented. Here we report on the morphology of PPL pollen along a middle to upper Eocene sedimentary sequence in cent...

The ongoing surge of international research on Asian Climate and Tectonics enables to better assess interactions between forcing mechanisms (global climate, India-Asia collision, Tibetan Plateau growth) and paleoenvironmental changes (monsoons, aridification), land-sea distribution, surface processes, paleobiogeographic evolution and the global car...

The paleogeographic evolution of the India-Asia collision and the resulting formation of the Himalayan orogen remain an intensely debated topic. A variety of disputed models propose different collision ages for the numerous terranes incorporated into the collision with variable paleolatitudes and tectonic rotations that can be constrained using pal...

The Poaceae (the grass family) includes over 11000 species and covers large part of the Earth land surfaces. Their history is rooted in the Cretaceous, but this group only expanded fully over the globe during the late Miocene. In the Amazon drainage basin (ADB) grasses were at the core of a heated debate, in which it was hypothesized that during th...

Mountains are arguably Earth's most striking features. They play a major role in determining global and regional climates, are the source of most rivers, act as cradles, barriers and bridges for species, and are crucial for the survival and sustainability of many human societies. The complexity of mountains is tightly associated with high biodivers...

The riverine barrier hypothesis is a central concept in Amazonian biogeography. It states that large rivers limit species distributions and trigger vicariant speciation. Although the hypothesis has explanatory power, many recent biogeographical observations addressing it have produced conflicting results. We propose that the controversies arise bec...

Alexander von Humboldt conducted his best‑known work on the slopes of the Ecuadorian Andes. He did this by applying his own characteristic brand of multidisciplinary scientific approach. This consisted of thorough data collection while synthesizing and visualizing the data in innovative formats. Also important for his scientific success in South Am...

Alexander von Humboldt is often regarded as the "Father of Biogeography". Although the very concept that any discipline has a founder may be disputed, von Humboldt´s contributions are, without a doubt, enormous, integrative and global. His lucid writing was widely read, he built up a huge network of correspondents, he assisted many young researcher...

To reconstruct the timing and underlying forcing of major shifts in the composition of terrestrial ecosystems in arid Central Asia during the late Cenozoic (past ~7 Ma), we carry out palynological analysis of lake sediments from the Qaidam Basin (NE Tibetan Plateau, China). Our results show that the steppe/semi-desert biomes dominating the Qaidam B...

Mountains are arguably Earth’s most striking features. They play a major role in determining global and regional climates, are the source of most rivers, act as cradles, barriers and bridges for species, and are crucial for the survival and sustainability of many human societies. The complexity of mountains is tightly associated with high biodivers...

Mountains are arguably Earth’s most striking features. They play a major role in determining global and regional climates, are the source of most rivers, act as cradles, barriers and bridges for species, and are crucial for the survival and sustainability of many human societies. The complexity of mountains is tightly associated with high biodivers...

Fossil palm pollen referred to genera such as Longapertites, Spinizonocolpites, Palmaepollenites, and Dicolpopollis, and the palm-like Proxapertites had a very widespread distribution during the Paleogene. Here we investigate the fossil palm pollen within the composition of the latest middle to earliest late Eocene Yaw Formation in the Kalewa regio...

The rainforests of Amazonia comprise some of the most biologically diverse ecosystems on Earth. Despite this high biodiversity, little is known about how landscape changes that took place in deep history have affected the assembly of its species, and whether the impact of such changes on biodiversity can still be observed. Here, we present a hypoth...

The Himalayan-Tibetan orogen is generally considered as the archetype for continent-continent collisional systems , being the result of the accretion of numerous terranes including notably the India-Asia collision. However, the geodynamic evolution of the India-Asia collision remains a controversial issue, as illustrated by the widely different com...

Poaceae (the grass family) originated in the Cretaceous, but first dominate the palynological records of the Amazon drainage basin (ADB) in the Neogene (23 to 2.5 million years ago (Ma)). However, the ecological role of grasses in the landscape during this me remains to be resolved. In this paper, we summarise the global signi cance of grasses and...

The evolution of the tropical lowland forests in northern South America is poorly understood, yet new insights into past composition and changes through time can be obtained from the rich and diverse fossil pollen record. Here we present a revision of two diagnostic Malvaceae taxa from the Cenozoic record of northern South America and we relate the...

The fall into the Oligocene icehouse is marked by a steady decline in global temperature with punctuated cooling at the Eocene-Oligocene transition, both of which are well documented in the marine realm. However, the chronology and mechanisms of cooling on land remain unclear. Here, we use clumped isotope thermometry on northeastern Tibetan contine...

The geological history of the Burmese subduction margin, where India obliquely subducts below Indochina, remains poorly documented although it is key to deciphering geodynamic models for the evolution of the broader Tibetan-Himalayan orogen. Various scenarios for the evolution of the orogen have been proposed, including a collision of India with My...

We review geological evidence on the origin of the modern transcontinental Amazon River, and the paleogeographic history of riverine connections among the principal sedimentary basins of northern South America through the Neogene. Data are reviewed from new geochronological datasets using radiogenic and stable isotopes, and from traditional geochro...

The unparalleled biodiversity found in the American tropics (the Neotropics) has attracted the attention of naturalists for centuries. Despite major advances in recent years in our understanding of the origin and diversification of many Neotropical taxa and biotic regions, many questions remain to be answered. Additional biological and geological d...

Mountains are key features of the Earth’s surface and host a substantial proportion of the world’s species. However, the links between the evolution and distribution of biodiversity and the formation of mountains remain poorly understood. Here, we integrate multiple datasets to assess the relationships between species richness in mountains, geology...

The scene for regional biogeography and human settlements in Central Amazonia is set by the river network, which presumably consolidated in the Pliocene. However, we present geomorphological and sediment chronological data showing that the river network has been anything but stable. Even during the last 50 kyr, the tributary relationships have repe...

The scene for regional biogeography and human settlements in Central Amazonia is set by the river network, which presumably consolidated in the Pliocene. However, we present geomorphological and sediment chronological data showing that the river network has been anything but stable. Even during the last 50 kyr, the tributary relationships have repe...

The Cenozoic vegetation history of Central Myanmar is only sparsely documented and yet of great interest in the context of regional paleogeographic and climatic changes. The Kalewa section, situated in the Central Myanmar Basin and recently dated by our group (Myanmar Paleoclimate and Geodynamics research group), presents an excellent opportunity t...

Nitraria is a halophytic taxon (i.e., adapted to saline environments) that belongs to the plant family Nitrariaceae and is distributed from the Mediterranean, across Asia into the south-eastern tip of Australia. This taxon is thought to have originated in Asia during the Paleogene (66–23 Ma), alongside the proto-Paratethys epicontinental sea. The e...

Botanical materials. Here we list all the materials that were given on loan from different herbaria to carry out this study

Measurements of morphological characteristics and FTIR chemical spectra of extant Nitraria and Peganum pollen (all morphological measurements in µm)

Phylogenetic tree file of Nitrariaceae obtained from Zhang et al. (2015) and used to create the phylomorphospace and phylochemospace

Rcode used for data analysis

Coordinates of the plotted specimens in Fig. 1, obtained from GBIF, Tropicos or own material described in Appendix S2

Summary table of the 24 morphological characters used to describe the Nitraria and Peganum pollen in this study

Boxplots comparing the 18 numerical morphological characters used for pollen morphological analysis between the eight studied species

The Amazon River nutrient-rich plume currently triggers large-scale phytoplankton blooms in the otherwise oligotrophic western tropical Atlantic Ocean. Little is known about the onset and development of this high productivity system, although a direct link to the transcontinental Amazon River evolution can be expected. The Amazon submarine fan, loc...

Aim The high biodiversity of northern South America is unparalleled and includes several centres of diversity such as Amazonia, the Andes and the Chocó. Movement of lineages amongst and within these bioregions is thought to be rare, and the effect of those dispersals on the distribution, diversity, and community assembly remains poorly understood....

The outstanding biodiversity found in the American tropics (the Neotropics) has attracted the attention of naturalists for centuries. Despite major advances in the generation of biodiversity data, many questions remain to be answered. In this review, we first summarize some of the knowns and unknowns about Neotropical biodiversity, and discuss how...

The outstanding biodiversity found in the American tropics (the Neotropics) has attracted the attention of naturalists for centuries. Despite major advances in the generation of biodiversity data, many questions remain to be answered. In this review, we first summarize some of the knowns and unknowns about Neotropical biodiversity, and discuss how...

The Amazon submarine fan is a large sediment apron situated offshore Pará (Brazil) and represents the most distal extent of the Amazon River. The age of onset of this transcontinental river remains debated, yet is of great importance for understanding biotic evolutionary processes on land and at sea. Here we present new geochemical and palynologica...

Since the extrusion and rotation of the Indochina Peninsula following the India-Asia collision, the convergence of India relative to Myanmar has been highly oblique. This high obliquity has resulted in the strike-slip partitioning of the 1100-km long forearc basin of central Myanmar into individual pull-apart basins, as well as the early build-up o...

The Asian monsoons affect the lives of one third of the human population, yet the controls on monsoon intensity and longevity are not fully understood. Recent studies have highlighted that the South Asian monsoon is as old as the Eocene; early monsoonal intensity has been proposed to be driven by variations in atmospheric pCO2. This study proposes...