# Response of vegetation to hydroclimate changes in northeast Brazil over the last 130 kyrs

Patricia Piacsek, Hermann Behling, Nicolás Stríkis, João Ballalai, Igor Venancio, Alice Maria da S. Rodrigues, Ana Luiza S. Albuquerque

► To cite this version:

Patricia Piacsek, Hermann Behling, Nicolás Stríkis, João Ballalai, Igor Venancio, et al.. Response of vegetation to hydroclimate changes in northeast Brazil over the last 130 kyrs. Palaeogeography, Palaeoclimatology, Palaeoecology, 2022, 605, pp.111232. 10.1016/j.palaeo.2022.111232. hal-05001137

HAL Id: hal-05001137

https://hal.univ-brest.fr/hal-05001137v1

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1 **Response of vegetation to hydroclimate changes in northeast Brazil**
2 over the last 130 kyrs

3

4 Patricia Piacsek¹*, Hermann Behling³, Nicolás M. Stríkis⁵, João M. Ballalai⁴,⁵, Igor M.

5 Venancio⁵, Alice Maria da S. Rodrigues⁵, Ana Luiza S. Albuquerque²

6

7 ¹Centro de Geociencias, Universidad Nacional Autónoma de México (UNAM), Blvd.

8 Juriquilla 3001, Campus UNAM 3001, 76230, Juriquilla, Querétaro, México

9 ²Programa de Pós-Graduação Dinâmica dos Oceanos e da Terra (DOT-UFF),
10 Fluminense Federal University, Av. Gen. Milton Tavares de Souza s/nº, Gragoatá,
11 Campus da Praia Vermelha, 24210346 Niterói, RJ, Brazil.

10

11

12 ³Department of Palynology and Climate Dynamics, University of Göttingen (UG),
13 Untere Karspüle 2, 37073 Göttingen, Germany

12

13

14 ⁴UMR 6538 Geo-Ocean, CNRS, IFREMER, UBO, UBS, Centre de Bretagne 29280
15 Plouzané, France

14

15

16 ⁵Geoquímica Ambiental, Fluminense Federal University (UFF), Outeiro São João

16

17 Batista, s/n – 5º andar Instituto de Química, Campus do Valonguinho Centro, 24020141
18 Niterói, RJ, Brazil.

17

18

19

20 *Corresponding author: Patricia Piacsek

21 Piacsek patricia@geociencias.unam.mx

22 Tel. +52 (442) 149-61-45

23

24 **Abstract:** In this paper, we use palynology and geochemical proxies to
25 reconstruct late Quaternary vegetation changes within the hydrographic basin of
26 Parnaíba, Northeast Brazil, over the last 130 kyrs. Findings are based on the analysis of
27 a marine sediment core (GL-1248) retrieved from the western equatorial Atlantic
28 (0°55.2'S, 43°24.1'W), close to the coast. Geochemical proxies (Fe/K ratio and εNd)
29 indicative of soil erosion match changes in reconstructed vegetation, suggesting a
30 dynamic pattern of hydrological disturbances and ecosystem evolution. Given that
31 reconstructed vegetation does not present the same response to precipitation anomalies
32 on the millennial scale, we sought the main drivers of vegetation changes in the
33 Parnaíba watershed. Results indicate that vegetation succession was primarily
34 influenced by austral insolation from March to May, which triggered changes in the
35 pioneer vegetation types. Our study improves the knowledge of tropical vegetation

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36 dynamics in an orbital framework, suggesting 23-kyr precessional cycles as the main
37 driver of landscape evolution in Northeast (NE) Brazil. We also infer that such past
38 climate change events may have been a key causal factor of the high biodiversity of the
39 Neotropics, mediated through the biological exchange of the Amazon and Atlantic
40 rainforest species via ecological forest corridors in the semi-arid Northeast Brazil.

41 **Keywords:** Marine-based Palynology, Northeastern Brazil, Soil Erosion, Vegetation
42 Reconstruction, Glacial-Interglacials, Climate Change.

43 **1 Introduction**

44 Many hypotheses have discussed the mechanisms that led to the current
45 rainforest distribution and its plant diversity (Colinvaux et al., 1996; Cárdenas et al.,
46 2011; Antonelli et al., 2011; Cohen et al., 2014). Hoorn et al. (2010) showed that the
47 merger between climate, bedrock, and edaphic conditions over the different Amazon
48 basin units is highly relevant to explain the actual biodiversity. Por et al. (1992)
49 proposed at least three different pathways that may have connected the Amazon forest
50 with the Atlantic coastal rainforest (Northwest–Southeast of South America, coastal
51 route of Northeastern Brazil, and montane route of Northeastern Brazil). Phylogenetic
52 and palynological studies point to ancient connections between the two forests and
53 indicate that both coastal and montane NE routes had gained relevance during the
54 Quaternary climate episodes (Fig. 1) (Batalha et al., 2013). The influence of climate
55 change on vegetation diversification has been considered regarding the richness of
56 Neotropical biodiversity (Por et al., 1992; Ledo & Colli, 2017; Silveira et al., 2019).
57 Hydrological changes over the Plio-Pleistocene may have promoted the spatial change
58 in the distribution of the gallery forests and the series of deciduous and semi-deciduous
59 forest patches bridging the Amazon and Atlantic rainforests (de Oliveira et al., 1999;
Behling et al., 2000; Costa, 2003; Pinaya et al., 2019; Piacsek et al., 2021b). During the last glacial period, those hydrological changes over the NE of South America were mainly governed by millennial-scale displacements of the Intertropical Convergence Zone (ITCZ) position and widely related to events known as Heinrich Stadials (HS) (Wang et al., 2004; Stríkis et al., 2018). The HS was depicted as an abrupt and extensive freshwater intrusion into the North Atlantic (Heinrich, 1988; Hemming, 2004), weakening the Atlantic Meridional Overturning Circulation (AMOC), with accentuated meridional sea surface temperature (SST) gradients and reduced inter-hemispheric energy transport (Burkel et al., 2015; Mulitza et al., 2017). Consequently, the atmospheric conditions rearranged with significant meridional changes in the intensity of trade winds and the ITCZ mean position (Deplazes et al., 2013). When the NE trade winds gained strength, warm superficial waters were restricted at the western equatorial Atlantic and probably enabled the permanence of the ITCZ at a more southward position, bringing Atlantic moisture onto the continent (Broccoli et al., 2006; McGee et al., 2018; Utida et al., 2019).

Within some HS events, underlining HS 1, the palynological records of the marine sediment core GeoB 3104-1 pointed to an increase in the relative abundance of rainforest pollen grains (e.g., *Alchornea*, Moraceae, Arecaceae, and others), suggesting an expansion of forests in NE Brazil (Behling et al., 2000). Jennerjahn et al. (2004) investigated high-resolution geochemical proxies (Fe/Ca and Ti/Ca) in the same marine core and identified millennial-scale sedimentation pulses related to the Younger Dryas (YD) and HS 1 to HS 8. The study identified the rise of pollen influx with a 1 to 2 kyr delay post-HS events, followed by the Fe/Ca ratio decrease, and suggested that the erosion was impaired post the development of the rainforest vegetation. Although both studies reconstructed the vegetation of NE Brazil using pollen resolution (52 samples at
intervals of 10 cm) in which 24 sediment samples covered the temporal range of 42 kyr to 20 kyr, other studies of past vegetation dynamics in NE Brazil have highlighted the plasticity of the rainforest vegetation with a high pollen resolution within HS 1 (40 samples at intervals of 2–3 cm) and the YD (47 samples at intervals of 5 cm) (Dupont et al., 2010; Bouimetarhan et al., 2018). Both vegetation reconstructions were placed in different marine sediment cores over NE Brazil and pointed out the enhancement of rainforest in two steps within high precipitation levels on a millennial scale. Both studies are restricted to the vegetation change within one millennial-scale precipitation anomaly. Here, we provided the reconstructed vegetation with a higher resolution than the GeoB 3104-1 record for the last glacial period. The new pollen record of the marine sediment core GL-1248 will provide the vegetation changes in the Hydrographic Basin of Parnaíba (HBP) for the last ~130 kyr. We focus on three major vegetation groups (tropical dry forest, lowland rainforest, and wetland) and how the ecosystem shifts are related to the soil erosion processes within the HBP. The discrepancy in water requirements between tropical dry forests and lowland rainforests is discussed, reflecting the hydroclimatic mechanisms in NE Brazil that triggered the vegetation change over the last glacial period.

## 2 The study area

The marine sediment core GL-1248 (0°55.2'S, 43°24.1'W) was retrieved from the continental slope (2264 m below sea level) off NE Brazil, located at a distance of about 160 km from the modern coastline and about 280 km from the fan of the Parnaíba River (Fig. 2). The Parnaíba River plume flows northward at the sea surface, transported by the North Brazil Current (NBC). The NBC is the superficial layer of the western boundary current and the main component for transporting heat to high latitudes of the North Atlantic. Its formation occurs at 10°S from the South Equatorial Current (SEC)
bifurcation. The northern excursions of the ITCZ and stronger southeast trade winds strengthen the NBC transport during the austral winter (Stramma et al., 1995; Johns et al., 1998).

The arrival of the austral autumn (March–April–May) marks the southernmost position of the ITCZ (2°S) (Shimizu et al., 2021) in response to the seasonal warming of the adjacent tropical Atlantic Ocean. The ITCZ reaches the HBP during this time and triggers the highest Parnaíba River discharge. The HBP is located between the coordinates 02°21'S and 11°06'S latitude and 47°21'W and 39°44'W longitude and shelters three states (Ceará, Maranhão, and Piauí). The HBP has an area of 340,000 km², and it is recognized as an ecotone zone with extensive areas of vegetation transitions, where the landscape evolution is highly dependent on the precipitation amount (Castro et al., 1998). Correia Filho et al. (2019) showed a median and interquartile range of seasonal rainfall variability of biomes in NE Brazil from 1979 to 2013: Amazon rainforest (1847.9 mm ± 418.7 mm), *caatinga* (773.1 mm ± 212.5 mm), *cerrado* (1196.6 mm ± 218.9 mm), and Atlantic rainforest (1363.8 mm ± 217.0 mm).

The *caatinga* has distinct vegetation physiognomic types such as xeric shrubland, shrub woodland, deciduous trees, and other drought-tolerant plants (Kuhlmann, 1977; Cole, 1986). It is highly represented by trees that belong to the Anacardiaceae (e.g., *Astronium*, *Schinopsis*), Apocynaceae (*Aspidosperma*), Malvaceae, and Fabaceae (e.g., *Ambulana*, *Caesalpinia*, *Calliandra*, *Senna*, *Mimosa*, *Pithecellobium*) (Bouimetarhan et al., 2018). Both biomes (*caatinga* and *cerrado*) may overlap in the transition zones. The *cerrado* (savanna to tropical dry forest) separates the *caatinga* (typical semi-arid dry forest) from the Amazon rainforest and is characterized by the occurrence of *Byrsonima*, *Mimosa*, and *Didymopanax* (Bouimetarhan et al., 2018). The lower part of the HBP has a perennial regime of superficial water flow with humid forest and
extensive floodplains covered by herbaceous vegetation, swamps, and gallery forests
(Lima & Melo 1985), marked by the presence of Moraceae-Urticaceae, Cyperaceae, and
*Mauritia* (Ledru et al., 2002).

## 3 Material and methods

### 3.1 X-ray fluorescence Ti/Ca and Fe/K ratio

Sediment chemistry was analyzed by scanning the core surface of the archive
half with X-ray Fluorescence (XRF) Core Scanner II (AVAATECH Serial No. 2) at the
MARUM, University of Bremen (Germany) (Venancio et al., 2018). The XRF data
were measured downcore every 0.5 cm of GL-1248 for the chemical elements Al, Si, K,
Ca, Ti, Mn, Fe by measuring their characteristic radiation. The elements were selected
according to the distribution of major elements in Atlantic surface sediments (Govin et
al., 2012). The Ca fluxes in this environment are derived mainly from biogenic CaCO₃
shells, and changes in Ca concentrations are most likely due to dilution by non-
carbonate sediments (Govin et al., 2012; Nace et al., 2014). In contrast, Ti and Fe are
mostly found in the soil residing in heavy minerals. During rainy periods and substantial
runoff, the soil is revolved, carrying Ti and Fe, lined up with some siliciclastic material
of fluvial origin (Govin et al., 2012). Among the available elements, the Ti/Ca ratio was
used to indicate the erosion and soil contribution to the marine sediment core (Arz et al.,
1998; Jennerjahn et al., 2015), and peaks of the Fe/K ratio were used to indicate relation
to deep weathering process during wet periods (Mulitza et al., 2008).

### 3.2 Chronology

The age model of the GL-1248 was defined based on 12 analyses of radiocarbon
dating using Accelerator Mass Spectrometry (AMS) measurements for the upper 550
cm (Venancio et al., 2018). For radiocarbon dating, we used two planktonic
foraminifera types, *Globigerinoides ruber* and *Trilobatus sacculifer* (>150 mm), and it
160 was performed at the Beta Analytic Radiocarbon Dating Laboratory, USA. The
161 radiocarbon ages were calibrated with the IntCal13 calibration curve (Reimer et al.,
162 2013), with a reservoir age of 400 ± 200 years (2σ) with no additional local reservoir
163 effect (ΔR = 0) (Mulitza et al., 2017). The downcore ages were modeled using the
164 software clam 2.2 (Blaauw, 2010), where 1665 to 564 cm correspond to 128 to 40 kyr,
165 respectively. Most of the tie points were located at the midpoint between the alignment
166 of the major Ti/Ca fluctuations and the abrupt oscillations of the δ¹⁸O isotopes from the
167 ice cores of the North Greenland Ice Core Project (NGRIP members, 2004). The core
168 GL-1248 is ~19 m long and spans the interval between 2 and ~130 kyr. The complete
169 age-depth model was published in Venancio et al. (2018) (Fig. S1 and S2).

3.3 Palynological sample preparation

171 The sediment samples were prepared for pollen and spores analysis using 4-6 g
172 (wet weight) following the standard laboratory procedures (Faegri & Iversen, 1989),
173 excluding acetolysis. The sediment samples were sieved with a 150 µm mesh to remove
174 the larger particles, such as shells and small stones. After that, one tablet of exotic
175 *Lycopodium clavatum* spores (20848 ± 1546) was added to each sample to estimate the
176 concentration (grains/cm³) and pollen influx (grains/cm²/yr) values (Stockmarr et al.,
177 1971). The samples were treated with hydrochloric acid (HCl, 35%) for decalcification
178 and cold hydrofluoric acid (HF, 40%) to remove the siliceous content. After the
179 chemical treatment, samples were moved to an ultrasonic bath (maximum 30 seconds)
180 for organic matter disaggregation. The samples were sieved with a 1 µm nylon mesh to
181 remove small particles. The samples were processed at the Department of Palynology
182 and Climate Dynamics, University of Göttingen (Germany).

3.4 Palynological analysis

184 A total of 140 sediment samples were collected from the GL-1248 core,
following the Ti/Ca ratio peaks as an indicator of the primary source of the continental deposition as previously reported in Piacsek et al., (2021a). The pollen and spores were identified according to the reference collections of the Department of Palynology and Climate Dynamics (Göttingen, Germany). Pollen grains and spores were counted separately, each to a minimum of at least 100. An average of ~175 pollen grains and ~180 spores was counted per sample, with relative low concentrations during both interglacials. The pollen and spore concentration refers to the number of grains per unit volume of sediment, calculated for each sample by following the equation of Benninghoff (1962). The concentration can be converted to the influx of pollen and spore, a measure of the number of pollen grains incorporated into the sediment per year (grains/cm²/yr). For continental records, the fossil pollen and spore influx provide a potential proxy for quantitative biomass and population reconstructions (Davis and Deevey, 1964). However, factors other than biomass may affect the pollen influx of marine pollen records and must be interpreted carefully.

## 3.5 Vegetation groups

The palynological quality in the marine core GL-1248 reflects the different biomes of the Parnaíba watershed, with little influence of sea-level changes on the continental shelf. Palynological studies from NE Brazil for the last glacial period to the Holocene used ecological groups (de Oliveira et al., 1999; Behling, 2004; Ledru et al., 2006; Bouimetarhan et al., 2018). The most representative pollen groups were wetland, tropical dry forest (with the main recurrent taxa from *caatinga* and/or *cerrado* biomes), and lowland rainforest. The pollen types included for the wetland, lowland rainforest, and tropical dry forest groups are listed in Table 1, and the complete chart of pollen and spores can be found in the supplementary material (Fig. S3 to S9).

209
210 **4 Results**

211 **4.1 Pollen sum, pollen concentration, sedimentation rate, and pollen influx**

212 The total pollen sum accounts for arboreal pollen (AP) and nonarboreal pollen (NAP). The maximum sum of pollen counted per sample reached about 340, and the lowest value of pollen sum was ~100, with a mean value of ~175, illustrated by the red cut line (Fig. 3A). The pollen concentration in GL-1248 varied downcore from ~80 to 2200 grains/cm³ (average ~565 grains/cm³). During the glacial period, the lowest values of pollen concentrations were found from 55 to 40 kyr, indicating relatively reduced riverine contribution to the sediment core (Fig. 3B). In contrast, the sedimentation rate of the marine core GL-1248 displayed higher values during Marine Isotope Stage (MIS) 3 (~65 cm/kyr). Lower values were found during the interglacials and early glacial (~3 cm/kyr), with a mean sedimentation rate of 22 cm/kyr (Fig. 3C) (Venancio et al., 2018). We used the sedimentation rate to calculate the pollen influx, which varied from ~5.5 to ~1470 grains/cm²/yr (average 160 grains/cm²/yr) (Fig. 3D). However, the pollen signal of pollen influx was disguised by the sedimentation rate as the marine core was located at the continental slope and suffered a significant influence from the past sea-level oscillations (Fig. 3E) (Waelbroek et al., 2002). The palynological content was not sufficient (< 100 pollen grains per sample) for appropriate analysis for the section between ~100 to 90 kyr (1486 cm to 1392 cm) and between 7 to 2 kyr (80 cm to 23 cm). Due to the hiatus in core GL-1248 (~27 to ~16 kyr), the reconstruction of vegetation was not performed for the Last Glacial Maximum.

231 **4.2 Relative abundances of pollen and spore grains**

232 A total of 96 pollen taxa and 38 spores were identified. The relative abundance of pollen was calculated based upon the total pollen sum, and we used the total spores sum to calculate the relative abundance of spores. Following 12 pollen types present in
the most representative groups (wetland, lowland rainforest, and tropical dry forest) are highlighted due to their higher relative abundance: Cyperaceae (~38%), Malpighiaceae (~17%), Arecaceae (~13%), Asteraceae (~11%), Arecaceae *Mauritia* (~4,6%), *Borreria* (~8%), Mimosaceae (~5%), Moraceae-Urticaceae (~7,5%), Anacardiaceae (5%), *Alchornea* (~5%) *Amaranthaceae* *Gomphenera-Pfaffia* (~4,5%) *Amaranthaceae/Chenopodiaceae* (~4%) (Fig. 4). The higher relative abundance of spores are as follows: Cyatheaceae spp. sum (~39%), *Selaginella* (~20%), *Cyathea hemitelia* (~14%), Tree fern (~8%), and Trilete reworked (~31,5%) (Fig. S3). The higher relative abundance of Cyperaceae pollen occurred during the MIS 4 (~70 to ~60 kyr, or 1132 cm to 1022 cm) (Fig. 4). The completed pollen and spore diagrams are found on the supplementary material (Fig. S3 to S9), and the pollen data of GL-1248 were previously addressed in Piacsek et al. (2021b).

The percentage of the main pollen groups (tropical dry forest, lowland rainforest, and wetland) are displayed with a black line referring to their respective pollen concentration. The pollen concentration in the marine core GL-1248 was low, mainly due to the amount of sediment processed to reach a minimum of 100 pollen units per sample. Furthermore, the pollen concentration depends on pollen production and transport efficiency (Maher, 1981). The pollen concentration of the wetland group was increased within the MIS 4, achieving higher values (~180 grains/cm³) than its total average (~90 grains/cm³). As previously mentioned, the lowest pollen concentration was found from 55 to 40 kyr, however, the pollen concentration of tropical dry forest (average of 75 grains/cm³) was superior to that of the lowland rainforest (average of 50 grains/cm³).

258
**5 Discussion**

**5.1 The landscape changes and their implications for soil erosion within the HBP**

We have established the age model of the GL-1248 core based on radiocarbon dates up to ~40 kyr and by the alignment between the peaks of Ti/Ca ratio and δ¹⁸O isotopes well marked in the NGRIP over the last 130 kyr (Venancio et al., 2018) (Fig. 5A). During HS events, the western Atlantic ITCZ migrated to the southernmost position and contributed to enhancing local river catchments. In this sense, high Ti/Ca ratio values from GL-1248 suggest prolonged precipitation events over NE Brazil and a substantial contribution from rivers to the adjacent ocean (Fig. 5B) (Govin et al., 2012; Nace et al., 2014).

Periods of intense precipitation in NE Brazil enhanced the deep weathering and are also related to high Fe concentrations in the marine sediment compared to the more soluble K (Govin et al., 2012; Nace et al., 2014). Thus, we concluded that rapid increases in the Fe/K ratio of GL-1248 (Fig. 5C) are also related to precipitation anomalies over NE Brazil and intense weathering within the HBP. At the same time, the Fe/K is detached from the age model avoiding circularity in the reasoning. We found lower values of Fe/K during warmer interglacials, but the YD and substage MIS 5d (~110 kyr) depicted an increase of Fe/K. However, Fe/K was not depicted as during glacial Stadials, which might be explained by the increased distance between the coastline and the GL-1248 sediment core due to the rise in sea level during the interglacials (Fadina et al., 2019; Piacsek et al., 2021a). The higher sea levels flooded the continental shelf and hampered the arrival of terrigenous material to the location of the marine core as corroborated by the low pollen content for the interglacials.

The precipitation anomalies of the last glacial period enhanced the Parnaíba river discharge carrying terrigenous material. The HBP has an extensive drainage basin with
riparian vegetation at the flank of the rivers, several inundated areas, and swamp areas (Velloso et al., 2002). In coastal areas, the occurrence of Cyperaceae is a good indicator for salty marshlands (Behling et al., 2001) and swampy areas (Behling et al., 2001; Behling et al., 2004; Oliveira et al., 2013). The Cyperaceae pollen was the most representative pollen type within the wetland pollen group, and its relative abundance guided the general trend of this group. The wetland group reached values above 35% during MIS 4 (70 to 60 kyr) and within the several HS events of the last glacial period (Fig. 5D). The wetland group (Fig. 4) displayed higher values (~180 grains/cm³) during MIS 4 and an average higher than ~130 grains/cm³ within the HS events. Hence, despite being an anemophilous taxon with overrepresented pollen production compared to zoophilous tropical trees (Subba Reddi & Reddi, 1986), the Cyperaceae has the potential to reflect the enhancement in the Parnaíba river discharge due to its location of occurrence.

The lower values of Fe/K and Ti/Ca ratios were found between the interval of 55 kyr to 40 kyr, indicating the reduced continental contribution to the sediment core and reinforced by lower pollen concentration. For the same time interval, the percentage of the tropical dry forest pollen increased from ~9% to 28% (Fig. 5E), mainly driven by the occurrence of Asteraceae (~1% to ~10%). High relative abundance of Asteraceae may indicate selective disruption, commonly associated with disturbed or open habitats (McConnachie et al., 2011; Dingemans et al., 2014; Florenzano et al., 2015). Drier air and soil may lead plants to adjust their ecophysiological processes as vegetation cover declines, leading to less pollen production and shifts of the plant community to C4 species, shrubs, and other drought-tolerant species (Pennington et al., 2009). More sparse vegetation increases the root/shoot ratio, making the soil less stable (Boonman et al., 2019; Chen et al., 2019; Flores et al., 2020).
The lower soil stability during a prolonged dry period over the onset of MIS 3 possibly favored high erosion rates during the wet HS 5, as evident from the lower values of radiogenic εNd isotopes in the sediment core GL-1248 (de Sousa et al., 2021). The εNd isotopes are unaffected by weathering processes, and low εNd values (non-radiogenic) were indicative of erosion that revolved the oldest material and deposited it in the adjacent ocean. Despite erosion and weathering being related processes, they are not identical. Erosion indicates the removal of soil and rock materials, while weathering implicates the disintegration of rocks and minerals on Earth. During HS 5, the Ti/Ca (erosion indicator) and Fe/K (chemical weathering indicator) ratios also displayed high peaks (Fig. 5B and 5C) indicating robust load contribution of the river discharge to the adjacent ocean. The relative abundance of *Selaginella* depicted a singular rise within the HS 5 (~20%) (Fig. 5F) corroborating the reduced soil stability from ~55 to 40 kyr, as it grows on moist soil and may be used as a proxy for erosion during intense precipitation events (Behling, 2000). We suggest that the previous development of the tropical dry forest and more open landscapes was intrinsically related to lower soil stability.

Prolonged periods of rainfall do not necessarily produce considerable soil erosion if it occurs in a well-established forest (Gyssels et al., 2005), as reflected by the anti-phase pattern between the rainforest vegetation and the Fe/K ratio by the late MIS 4 and within the HS 4. The rainforest vegetation reached higher values post-HS 6 and within HS 4 events (Fig. 5G). In contrast, the wetland pollen grains and spores of *Selaginella* synchronically decayed to low values. The pollen concentration of the rainforest lowland displayed the increasing trend as opposed to the pollen concentration of tropical dry forest and wetland groups (Fig. 4). Jennerjahn et al. (2004) pointed to the increase of pollen influx post several HS events without discriminating the types of pollen used, and argued that the HS events enabled the expansion of humid forests in
NE Brazil. Our study covers a more extended period, and the results revealed no uniform responses from the lowland rainforest to different HS events. The lowland rainforest response denotes that possibly other factors may overlap the precipitation anomalies of NE Brazil.

## 5.2 Reconstructed vegetation in response to regional hydroclimate variability

The dominance of vegetation at a particular latitude is determined by the global temperature and moisture distribution, creating latitudinal climate zones (Kozlowski & Pallardy 1997). Today, only two ice sheets cover most of Greenland and Antarctica. However, the climate was colder during the last glacial period due to orbital forcing, and the ice sheets progressively increased. Massive sheets of ice trapped water, exposing continental shelves and lowering the absolute humidity in the atmosphere due to a reduction in both evaporation and precipitation, and generated a constrained hydrological cycle (Bush and Philander, 1998; Gasse, 2000; Muhs, 2013). The orbital forcing is thought to drive major shifts in the climate zones, potentially leading to natural fluctuations of biome boundaries (Tardif et al., 2021). Based on this, we intend to investigate how the biomes at the ecotone region of HBP rearranged over distinct conditions of global temperature and moisture distribution.

The main fluctuations in the lowland rainforest reflected in the GL-1248 record were consistent with the significant global temperature changes recorded in the Antarctic ice core (Petit et al., 1999) for the glacial period (Fig. 6A and 6B). Piacsek et al. (2021b) showed that the lowland rainforest dwindled during the last glacial period as the montane rainforest progressed, indicating global temperature as a relevant factor to the disposition of biomes in the region of HBP. However, the temperature decay of the last glacial period was not constant, with peaks in global temperature as registered in the Antarctic ice core. A warmer planet strengthens the hydrological cycle and intensifies
the moisture-holding capacity of the atmosphere (Stalg et al., 2014). Some of those abrupt warmings were followed by gains in the lowland rainforest. Before suggesting that the rise in global temperature was the main controlling factor to the rainforest lowland, we must highlight two observed patterns: 1) The opposite trend with high percentages of lowland rainforest concomitant with the drop in global temperature, as observed after the last interglacial, between 115 to 104 kyr BP. 2) A decoupling between the response of lowland rainforest and the peak of global temperature during the HS 5 event. The response of lowland rainforest during the HS 5 indicates that the rise of global temperature did not lead to positive hydrological changes in the region of HBP.

Petit et al. (1999) highlighted that the glacial-interglacial difference in temperature (ΔT) showed a frequency of orbital cycles in the 100-kyr band, followed by a 41-kyr band, while the δ¹⁸O atm which reflects changes in the global hydrological cycle, strongly imprinted the precessional frequencies (23-kyr) for the entire Vostok record. In NE Brazil, the growth phases of speleothems from Toca da Boa Vista cave (TBV; 10°11'S, 40° 58'W) were ascribed to wet periods (Wang et al. 2004). The authors correlated the growth phases of speleothems to the maximum autumn insolation (MAM), a period of high land-sea thermal contrast, improving the transport of water vapor toward the land. So far, the NE Brazil does not have another speleothems/travertine record that covers an equivalent period of time to ensure the association between the speleothem growth and the high moisture levels. However, the lowland rainforest of GL-1248 responded positively to the maximum autumn insolation (Fig. 6B and 6D), and the establishment of the lowland rainforest is recurrent in regions with dry seasons shorter than 4 months (Clapperton, 1993). High values of lowland rainforest occurred by HS 4, within MIS 4, and over part of the early glacial period
around ~110 kyr and ~80 kyr, concomitant with the maximum autumn insolation, corroborating with the high moisture levels for the region. We applied a 23 kyr bandpass filter to extract potential low-frequency components of solar and orbital signals for defining past climate variability (Fig. 6C and 6F). Thus, the precession changes should not be disregarded once it modulates austral autumn insolation at the equator and alters the incidence of heat received by the tropics, controlling the transport of humidity from ocean to land (e.g., Clement et al., 2004; Cruz et al., 2005).

Tropical dry forests include vegetation types that experience a minimum dry season of 5-7 months with strong seasonal and ecological functions such as the presence of deciduous trees and thorns (Pennington et al., 2006; Pennington et al., 2009). The onset-to-mid MIS 3 presented an increase in the percentage of the tropical dry forest despite prolonged precipitation events such as the HS 5a and HS 5. The HS 5 event occurred during the autumn insolation minimum when the transport of water vapor toward the continent was impaired. We suggest that despite being a millennial-scale event, HS 5 may have presented milder precipitation anomalies or precipitation anomalies restricted to an annual season in NE Brazil, inhibiting the development of the lowland rainforest. In this sense, we interpreted that the minimum insolation during the austral autumn has extended the dry season over NE Brazil, favoring the expansion of tropical dry forest vegetation due to the adaptive mechanisms that enable its existence in water stress conditions (Fig. 6D and 6F). Thus, the predominance of the tropical dry forest by the onset-to-mid MIS 3 suggests drier conditions than MIS 4 for NE Brazil.

Recently, the first evidence of the influence of obliquity in the NE Brazilian tropical dry forest was published (Ferreira et al., 2022). The study carried out in the watershed of the São Francisco River suggested that maximum obliquity decreased the length of the dry season to 7 months or less. According to Ferreira et al. (2022), the
409 maximum obliquity intensified the southeast trade winds carrying moisture from the  
410 ocean to the continent and triggering the expansion of *cerrado* tree-dominated  
411 vegetation (C3 plants) versus savanna and grassland formations (C4 plants) during the  
412 last glacial period. The length of our pollen records hampers a statistically robust  
413 detection of obliquity periodicities through time-series analyses, but the percentage of  
414 the tropical dry forest data does not seem to follow the obliquity changes (Fig. 6E and  
415 6G). The ITCZ position strongly influences the HBP, and it is counterintuitive to infer  
416 that the further north the ITCZ is displaced, the shorter is the dry season in NE Brazil.

417 The increasing continental load to the Cariaco Basin (10°40.69′N, 64°58.29′W) 418 detached by the low reflectance values, points to northward ITCZ excursions (Deplazes 419 et al., 2013). According to Figure 6H, the percentage of the tropical dry forest of HBP 420 follows the meridional displacement of the ITCZ during the last glacial period. The 421 influence of the ITCZ position was also imprinted on the percentage of the tropical 422 forest of Cariaco during the last glacial period (Fig. 6I) (Gonzalez et al., 2008; Hessler 423 et al., 2010). The in-phase pattern between the decline in the percentage of tropical 424 forest in the Cariaco basin and the percentage of tropical dry forest found in the GL- 425 1248 record emphasizes the high dependence on the position of the ITCZ during the last 426 glacial period (Fig. 6G, 6H, and 6I). However, the percentage of tropical forest in the 427 Cariaco basin prevents further comparisons beyond the last glacial period. In contrast, 428 the resolution achieved in the GL-1248 indicates that the 23-kyr cycle prevailed on the 429 millennial scale over the entire record of the tropical dry forest. We suggest that the 430 ecophysiological processes of tropical dry forests are the main factor for their 431 development under water stress conditions across the HBP.

432 **5.3 Succession pattern of trees in HBP**
Changes in the regional hydroclimate may cause large-scale natural disturbances in vegetation cover and erosion (Whitmore, 1991; Richards, 1996). The disturbance intensity may regulate the structure and species diversity within a forest domain (Finegan, 1996). Forest patches can regenerate from the growth of pioneer trees into the development of a secondary forest (or second-growth forest) when the effects of previous disturbances are no longer evident. In the initial phases of plant succession, resource partitioning results in differential distribution of species according to their ontogeny in specific environment conditions (environmental filtering) (Wright et al., 2010; Sterck et al., 2011; Spasojevic et al., 2014). To assess the ecological succession (Gentry, 1993; Marchant et al., 2002), we removed the relative abundance of NAP pollen taxa to prevent the influence of the river flow and sea-level changes in the tropical dry forest and lowland rainforest groups. The successional pattern was ascribed to the trees and shrubs taxa of the tropical dry forest and lowland rainforest groups (Table 2).

The early life stages of plants and the pioneer trees are known better to address niche differences (Poorter, 2007). The role of functional traits in plants due to environmental conditions drives a successional gradient. For example, as the rainforest increases, it enhances its air humidity and decreases the local air temperature; a similar pattern is found in the soil moisture (Rhoades et al., 1998; Callaway, 2007), restricting the establishment of drought-adapted species. The main difference between tropical dry forests and lowland rainforests resides in the tolerance to water stress, the length of the dry season, and the evapotranspiration behavior (Clapperton, 1993). According to this definition, we applied the 23 kyr bandpass filter on both pioneer and secondary forests to better understand how the regional hydroclimate has dictated the vegetation change (Fig. 7).
Both pioneer trees (tropical dry forest and lowland rainforest) displayed greater amplitude than the secondary forests, indicating a rapid and substantial response in the initial phases of plant succession. The coupling between pioneer trees of the tropical dry forest (lowland rainforest) with the minimum (maximum) insolation of autumn (Fig. 7A and 7B) indicates that the insolation/precession may play a crucial role in the regional moisture levels, driving the pioneer phase of the successional changes in the vegetation of NE Brazil. Although the secondary rainforest lowland has displayed a good match with the 23-kyr frequencies, the secondary forests of the tropical dry forest did not show such an apparent orbital pattern and deserved a further look.

During the rainy season, dry forest trees may reduce the differences between drought deciduous and evergreen dry forest species by presenting physiological similarities (Santos et al., 2012; Apgaua et al., 2014a; Apgaua et al., 2014b; Sunderland et al., 2015). In general, the rainy season may promote the dry forest trees to show values of carbon assimilation and stomatal conductance equal to those found in rainforest trees (Van Bloem, Murphy, and Lugo, 2004). The 23-kyr cycles highlight how the regional hydroclimate variability shaped the most tree types (rainforest lowland and tropical dry forest) found in the GL-1248. However, the inadequacy of the mature tropical dry forest in the 23-kyr cycles may be related to natural temporal variations within the tree community that we were unable to account for via our temporal resolution. Though, the results also reinforce the hypothesis that other types of vegetation have possibly replaced the tropical dry forests which underwent climate changes (Pennington et al., 2000), alluding to their vulnerability.
481 **6 Conclusions**

482 Multi-proxy records from the marine sediment core GL-1248 retrieved off NE
483 Brazil reveal the dynamic patterns of regional vegetation in response to the
484 hydroclimate of the last 130 kyr. The reconstructed vegetation for NE Brazil based on
485 pollen records has, for the first time, achieved an interglacial period beyond the
486 Holocene. We assessed the three most representative pollen groups: wetland, lowland
487 rainforest, and tropical dry forest. Our results showed how the vegetation distribution
488 changed and its implications on soil erosion. The main pollen type of the wetland
489 cluster was Cyperaceae, which displayed a coupled trend with millennial events of the
490 last glacial period. The Cyperaceae increased during the HS and was related to vigorous
491 discharge from the Parnaíba River. The moss fern (Selaginella) indicated the soil
492 stability throughout the HS events revealing a singular soil erosion within the HS 5. The
493 coordinated positive response between the values of Cyperaceae, Selaginella, and the
494 Fe/K ratio pointed to periods with lesser soil stability across the HBP. The group of
495 lowland rainforests displayed an anti-phase response to Cyperaceae, Selaginella, and the
496 Fe/K ratio. After comparing the pollen records with the changes in terrigenous input, we
497 suggest that the development of the tropical dry forest enhanced the soil erosion in the
498 HBP and consequently increased the continental load to the adjacent ocean.

499 The lowland rainforest did not display the same gain in pollen percentage
500 throughout the Heinrich Stadial of the last glacial period. The predominance of the
501 tropical dry forest by the onset-to-mid MIS 3 suggested drier conditions than MIS 4 for
502 NE Brazil. Despite the vegetation within the HBP being under the strong influence of
503 the ITCZ position, the discrepancies in the ecophysiological processes of tropical dry
504 forest and lowland rainforest seem to play the central role in the prevalence of each
505 group according to changes in the length of the dry seasons. The 23-kyr bandpass
filtering ascribed greater relevance to the regional maximum autumn insolation, which
dictates the ocean-continent transport of water vapor, strengthened (weakened) in
maximum (minimum) insolation periods. We used the ecological definition of pioneer
and secondary forest to understand the vegetation response to the hydroclimate
disturbances. Only the mature tropical dry forest did not imprint the 23-kyr cycles,
which may be related to physiological and structural variations within the tree
community that we were unable to account for.

The reconstructed vegetation of the GL-1248 record brought light to the climatic
mechanics that dictated the expansion of the tropical dry forest and lowland rainforest.
The fluctuations in the relative abundance of the vegetation types over the HBP, support
the hypothesis of biological radiation in the coastal route of NE Brazil and suggest the
main pacing of pioneer and secondary vegetation types occurring in the 23-kyr cycles.
The climate dynamics dictate the disposition of biomes that provide essential natural
resources for local societies. This study highlights the vulnerability of mature dry
forests and the need to improve mitigation, conservation, and adaptation strategies for
NE Brazil in the face of future climate changes.

7 Acknowledgments

We thank R. Kowsman (CENPES/Petrobras) and Petrobras Core Repository staff
(Macaé/Petrobras) for providing sediment core GL-1248. Brazil National Council for
the Improvement of Higher Education (CAPES) provided financial support to the first
author from the CAPES also financially supported Patricia Piacsek with a scholarship
from the CAPES-ASPECTO project (Grant 88887.091731/ 2014-01). NMS
acknowledges the support of CNPq (Grants 423573/2018-7; 308769/2018-0). We thank
the original data generators who made their data available for future comparisons. We
acknowledge the data repositories of Past Global Changes (PAGES) and the National
Oceanic and Atmospheric Administration (NOAA) that enable the paleoclimatic
community to enhance their discussions.

8 References

Antonelli, A., Sanmartín I. 2011. Why are there so many plant species in the Neotropics. Taxon. 60 (2), 403-414. DOI: https://doi.org/10.1002/tax.602010.

Arz, H.W., Pätzold, J., Wefer, G., 1999. The deglacial history of the western
Tropical Atlantic as inferred from high resolution stable isotope records off northeastern
Brazil. Earth Planetary Science Letters. 167, 105-117. DOI:
https://doi.org/10.1016/S0012-821X(99)00025-4

Apgaua, D.M.G., Coelho, P.A., Santos, R.M., Santos, P.F., Oliveira-Filho, A.T.
2014a. Tree community structure in a Seasonally Dry Tropical Forest remnant, Brazil.
Cerne. 20, 173-182. DOI:10.1590/01047760.201420021540

Apgaua, D.M.G., Santos, R.M., Pereira, D.G.S., Menino, G.C.O., Pires, G.G., Fontes, M.A.L., Tng, D.Y.P. 2014b. Beta-diversity in seasonally dry tropical forests (SDTF) in the Caatinga Biogeographic Domain, Brazil, and its implications for conservation. Biodiversity and Conservation. 23, 217-232. DOI:10.1007/s10531-013-0599-9

Batalha-Filho, H., Fjeldså, J., Fabre, P.-H., Miyaki, C.Y. 2013. Connections between the Atlantic and the Amazonian forest avifaunas represent distinct historical events. Journal of Ornithology. 154, 41-50. DOI: https://doi.org/10.1007/s10336-012-0866-7.

Behling, H., Arz, H.W., Pätzold, J., Wefer, G. 2000. Late Quaternary vegetational
and climate dynamics in northeastern Brazil, inferences from marine core GeoB 3104-1.
Quaternary Science Reviews. 19 (10), 981-994. DOI: https://doi.org/10.1016/S0277-3791(99)00046-3.
556

Behling, H., Cohen, M.C.L., Lara, R.J. 2001. Studies on Holocene mangrove
ecosystem dynamics of the Bragança Peninsula in northeastern Pará, Brazil.

557

558

Palaeogeography, Palaeoclimatology, Palaeoecology, 167(3-4), 225-242. DOI:
https://doi.org/10.1016/s0031-0182(00)00239-x

559

560

Behling, H., 2001. Late Quaternary environmental changes in the Lagoa da Curuça
region (eastern Amazonia, Brazil) and evidence of Podocarpus in the Amazon lowland.

561

562

Vegetation History and Archaeobotany. 10(3) 175-183. DOI:
https://doi.org/10.1007/pl00006929

563

564

Behling, H., Cohen, M.C.L., Lara, R.J. 2004. Late Holocene mangrove dynamics of
the Marajó Island in Amazonia, northern Brazil. Vegetation History and
Archaeobotany. 13 (2), 73-80. DOI: https://doi.org/10.1007/s00334-004-0031-1.

565

566

567

Benninghoff, W.S. 1962. Calculation of pollen and spores density in sediments by
the addition of exotic pollen in known quantities. Pollen et Spores. 4 (2), 332-333.

568

569

Berger, A., & Loutre, M-F. 1999. Parameters of the Earth's orbit for the last 5
million years in 1 kyr resolution. PANGAEA.

570

571

Blaauw, M. 2010. Methods and code for 'classical' age-modeling of radiocarbon
sequences. Quaternary Geochronology. 5 (5), 12-518. DOI:
https://doi.org/10.1016/j.quageo.2010.01.002.

572

573

574

Boonman, C.C.F., van Langevelde, F., Oliveras, I., Couédon, J., Luijken, N.,
Martini, D., Veenendaal, E.M. 2020. On the importance of root traits in seedlings of
tropical tree species. New Phytologist. 227 (1), 156-167. DOI:
https://doi.org/10.1111/nph.16370

575

576

577

578

Bouimetarhan, I., Chiessi, C.M., Gonzalez-Arango, C., Dupont, L., Voigt, I.,
Prange, M., Zonneveld, K. 2018. Intermittent development of forest corridors in
northeastern Brazil during the last deglaciation: Climatic and ecologic evidence.

579

580
581 Quaternary Science Reviews. 192, 86-96. DOI:

582 https://doi.org/10.1016/j.quascirev.2018.05.026.

583 Brazilian Institute of Geography and Statistics (IBGE). Maps of biomes and

584 vegetation. Available at: <https://www.ibge.gov.br/geociencias/informacoes-

585 ambientais/estudos-ambientais/15842-biomas.html?=&t=downloads>. (Accessed: July

586 13, 2022).

587 Broccoli, A.J., Dahl, K.A., and Stouffer, R.J. 2006. Response of the ITCZ to

588 Northern Hemisphere cooling, Geophysical Research Letters, 33, L01702,

589 DOI:10.1029/2005GL024546.

590 Burckel, P., Waelbroeck, C., Gherardi, J.M., Pichat, S., Arz, H., Lippold, H.,

591 Dokken, T., Thil, F. 2015. Atlantic Ocean circulation changes preceded millennial

592 tropical South America rainfall events during the last glacial. Geophysical Research

593 Letters, 42, 411-418. DOI: https://doi.org/10.1002/2014GL062512

594 Bush, A.B.G., Philander, S. G. H. 1998. The role of ocean-atmosphere interactions

595 in tropical cooling during the last glacial maximum. Science, 279, 1341-1344.

596 DOI:10.1126/science.279.5355.134

597 Callaway, R.M. 2007. Positive Interactions and Interdependence in Plant

598 Communities. Dordrecht: Springer.

599 Cárdenas, M.L., Gosling, W. D., Sherlock, S. C., Poole, I., Pennington, R. T.,

600 Mothes P. 2011. The response of vegetation on the Andean flank in western Amazonia

601 to Pleistocene climate change. Science. 331, 1055-1058. DOI: 10.1126/science.1197947

602 Castro, A.A.J.F., Martins, F.R., Fernandes, A.G. 1998. The woody flora of cerrado

603 vegetation in the state of Piaui, northeastern Brazil. Edinburgh Journal of Botany.

604 55(03), 455. DOI: https://doi.org/10.1017/s0960428600003292.
605 Chen, G., Hobbie, S., Reich, P.B., Yang, Y., Robinson, D. 2019. Allometry of fine 606 roots in forest ecosystems. Ecology Letters. 22, 322-331. DOI: 607 https://doi.org/10.1111/ele.13193

608 Clapperton, C.M. 1993. Nature of environmental changes in South America at the 609 Last Glacial Maximum. Palaeogeography, Palaeoclimatology, Palaeoecology, 101 (3- 610 4), 189-208. DOI: https://doi.org/10.1016/0031-0182(93)90012-8.

611 Clement, A.C., Hall, A., Broccoli, A.J. 2004. The importance of precessional signals 612 in the tropical climate. Climate Dynamics. 22 (4), 327-341. DOI: 613 https://doi.org/10.1007/s00382-003-0375-8.

614 Climate Change Knowledge Portal (CCKP). 2021. "Climate projections > CMIP5 615 data", available at: <https:// climateknowledgeportal.worldbank.org/download- 616 data>. (accessed July 13, 2022)

617 Cohen, M.C.L., Rossetti, D.F., Pessenda, L.C.R., Friaes, Y.S., Oliveira, P.E. 2014. 618 Late Pleistocene glacial forest of Humaita, western Amazonia. Palaeogeography 619 Palaeoclimatology Palaeoecology, 415, 37-47. DOI: 620 https://doi.org/10.1016/j.palaeo.2013.

621 Cole, M.M. 1986. The Savannas. Academic Press London 438 pp.

622 Colinvaux, P.A., de Oliveira, P.E., Moreno, J.E., Miller, M.C., Bush, M.B. 1996. A 623 long pollen record from lowland Amazonia, forest and cooling in glacial times. Science. 624 274, 85-88. DOI: http://doi.org/10.1126/science.274.5284.85.

625 Correia Filho, W.L.F., Oliveira-Júnior, J.F., Santiago, D.B., Terassi, P.M.B., 626 Teodoro, P.E., Gois, G., Blanco, C.J.C., Souza, P.H.A., Costa, M., Santos P.J. 2019. 627 Rainfall variability in the Brazilian northeast biomes and their interactions with 628 meteorological systems and ENSO via CHELSA product. Big Earth Data, 3, 315-337. 629 DOI: https://doi.org/10.1080/20964471.2019.1692298
630 Costa, L.P. 2003. The historical bridge between the Amazon and the Atlantic Forest of Brazil: a study of molecular phylogeography with small mammals. Journal of Biogeography. 30(1), 71-86. DOI: https://doi.org/10.1046/j.1365-2699.2003.00792.x.

633 Cruz, F.W., Burns, S.J., Karmann, I., Sharp, W.D., Vuille, M., Cardoso, A.O., Ferrari, J.A., Dias, P.L.S., Viana, Jr.O. 2005. Insolation-driven changes in atmospheric circulation over the past 116,000 years in subtropical Brazil. Nature. 434, 63-66. DOI: https://doi.org/10.1038/nature03365

637 Davis M.B., Deevey E.S. 1964. Pollen accumulation rates: estimates from Late- Glacial sediment Rogers Lake. Science. 145, 1293-95.

639 de Oliveira, P.E., Barreto, A.M.F., Suguio, K. 1999. Late Pleistocene/Holocene Climatic and Vegetational history of the Brazilian caatinga: the fossil dunes of the middle Sao Francisco River. Paleogeography, Paleoclimatology, Paleoecology. 152, 319-337. DOI: https://doi.org/10.1016/S0031-0182(99)00061-9

643 de Sousa, T.A., Venancio, I.M., Valeriano, C.d.M., Heilbron, M., Carneiro, W. D., Mane, M.A., de Almeida, J.C. H., Smoak, J.M., Albuquerque, A.L.S., Silva-Filho, E. V. 2021. Changes in Sedimentary Provenance and Climate off the Coast of Northeast Brazil since the Last Interglacial. Marine Geology. 435, 106454. DOI:10.1016/j.margeo.2021.106454

648 Deplazes, G., Lückge, A., Peterson, L.C., Timmermann, A., Hamann, Y., Hughen, K.A., Röhl, U., Laj, C., Cane, M.A., Sigman, D.M., Haug, G.H. 2013. Links between tropical rainfall and North Atlantic climate during the last glacial period. Nature Geoscience. 6, 213-217. DOI: https://doi.org/10.1038/ngeo1712.

652 Dingemans, T., Mensing, S.A., Feakins, S.J., Kirby, M.E., Zimmerman, S.R.H. 2014. 3000 years of environmental change at Zaca Lake, California, USA. Frontiers in Ecology and Evolution, 2.34. doi: 10.3389/fevo.2014.00034
655 Dupont, L.M., Schlütz, F., Ewah, C.T., Jennerjahn, T.C., Paul, A., Behling, H. 2010.

656 Two-step vegetation response to enhanced precipitation in Northeast Brazil during
657 Heinrich Event 1. Global Change Biology. 16 (6), 1647-1660. DOI:
658 https://doi.org/10.1111/j.1365-2486.2009.02023.x.

659 Fadina, O.A., Venancio, I.M., Belem, A., Silveira, C.S., Bertagnolli, D.d.C., Silva-
660 Filho, E.V., Albuquerque, A.L.S. 2019. Paleoclimatic Controls on Mercury Deposition
661 in Northeast Brazil since the Last Interglacial. Quaternary Science Reviews. 221,
662 105869. DOI:10.1016/j.quascirev.2019.105869

663 Faegri, K., Iversen, J. 1989. Textbook of pollen analysis (4th edition). Revised by K.
664 Faegri P.E. Kaland & K. Krzywinski. John Wiley and Sons (Chichester).

665 Ferreira, J.Q., Chiessi, C.M., Hirota, M., Oliveira, R.S., Prange, M., Haggi, C.S.,
666 Crivellari, C., Nandini-Weiss, S.D., Bertassoli, Jr.D.J., Campos, M.C., Mulitza, S.,
667 Albuquerque, A.L.S., Bahr, A., Schefuß, E. 2022. Changes in obliquity drive tree cover
668 shifts in eastern tropical South America. Quaternary Science Reviews. 279, 107402.
669 DOI:https://doi.org/10.1016/j.quascirev.2022.107402

670 Finegan, B. 1966. Pattern and process in neotropical secondary rain forests: The first
671 100 years of succession. Trends in Ecology & Evolution, 11(3). 119-24. DOI:
672 10.1016/0169-5347(96)81090-1

673 Florenzano, A, Marignani, M., Rosati, L., Fascetti, S., Mercuri, A.M. 2015. Are
674 Cichorieae an indicator of open habitats and pastoralism in current and past vegetation
675 studies? Blant Biosystems. 149,154-165. DOI:
676 https://doi.org/10.1080/11263504.2014.998311

677 Flores, B. M., Staal, A., Jakovac, C. C., Hirota, M., Holmgren, M., Oliveira, R. S.
678 2019. Soil erosion as a resilience drain in disturbed tropical forests. Plant and Soil. 450,
679 11-25. DOI:10.1007/s11104-019-04097-8
680 Gasse, F. 2000. Hydrological changes in the African tropics since the Last Glacial
681 Maximum. Quaternary Science Reviews, 19, 189-211. DOI: 10.1016/S0277-
682 3791(99)00061-X

683 González, C., Dupont, L. M., Behling, H., Wefer, G. 2008. Neotropical vegetation
684 response to rapid climate changes during the last glacial period: Palynological evidence
685 from the Cariaco Basin. Quaternary Research. 69(2), 217-230. DOI:
686 https://doi.org/10.1016/j.yqres.2007.12.00.

687 Gentry, A.H. 1993. Woody plants of northwest South America. Conservation
688 International, Washington, DC.

689 Govin, A., Holzwarth, U., Heslop, D., Ford, K.L., Zabel, M., Mulitza, S., Collins,
690 J.A., Chiessi, C.M. 2012. Distribution of major elements in Atlantic surface sediments
691 (36°N-49°S): Imprint of terrigenous input and continental weathering. Geochemistry,
692 Geophysics, Geosystems. 13 (1), 1-23. DOI: https://doi.org/10.1029/2011GC003785.

693 Gyssels, G., Poesen, J., Bochet, E., Li, Y. 2005. Impact of plant roots on the
694 resistance of soils to erosion by water: a review. Progress in Physical Geography. 29
695 (2), 189-217. DOI: https://doi.org/10.1191/0309133305pp443ra.

696 Hemming, S.R. 2004. Heinrich events: Massive late Pleistocene detritus layers of
697 the North Atlantic and their global climate imprint. Reviews Geophysics. 42(1). DOI:
698 https://doi.org/10.1029/2003RG000128

699 Hermanowski, B., da Costa, M.L., Carvalho, A.T., Behling, H. 2012.
700 Palaeoenvironmental dynamics and underlying climatic changes in southeast Amazonia
701 (Serra Sul dos Carajás, Brazil) during the late Pleistocene and Holocene.
702 Palaeogeography, Palaeoclimatology, Palaeoecology, 365-366, 227-246. DOI: 617
703 https://doi.org/10.1016/j.palaeo.2012.09.030.
704 Hessler, I., Dupont, L., Bonnefille, R., Behling, H., González, C., Helmens, K.F.,
705 Hooghiemstra, H., Lebamba, J., Ledru, M-P., Lézine, A-M., Maley, J., Marret, F.,
706 Vincens, A. 2010. Millennial-scale changes in vegetation records from tropical Africa
707 and South America during the last glacial. Quaternary Science Reviews, 29(21-22),
708 2882-2899. DOI:10.1016/j.quascirev.2009.11.029

709 Hoorn, C. Wesselinghh, F.P., Steegem, T., Bermudeza, A., Mora, Sevink, J.,
710 Sanmartín, I. Sanchez-Meseguer, A., Anderson, C.L.J., Figueiredo, P., Jaramillo, C.,
711 Riff, D., Negri, F.R., Hooghiemstra, H., Lundberg, J., Stadler, T., Särkinenan, T.,
712 Antonelli, D.A. 2010. Amazonia Through Time: Andean Uplift, Climate Change,
713 Landscape Evolution, and Biodiversity. Science. 330, 927. DOI:
714 10.1126/science.1194585

715 Jennerjahn, T.C., Ittekkot, V., Arz, H.W., Behling, H., Pätzold, J. Wefer, G. 2004.
716 Asynchronous terrestrial and marine signals of climate change during Heinrich Events.
717 Science. 306 (5705), 2236-2239. DOI: https://doi.org/10.1126/science.1102490.

718 Johns, W.E., Lee, T.N., Beardsley, R.C., Candela, J., Limeburner, R., Castro, B.
719 1998. Annual cycle and variability of the North Brazil Current. Journal of Physical
720 Oceanography. 28 (1), 103-128. DOI: https://doi.org/10.1175/1520-0485(1998)028<0103:ACAVOT>2.0.CO;2.

722 Kozlowski, T.T., Pallardy, S.G. 1997. Growth Control in Woody Plants. Academic
723 Press, San Diego, CA.

724 Kuhlmann, K. 1977. "Der Thron im alten Ägypten: Untersuchungen zu Semantik,
725 Ikonographie und Symbolik eines Herrschaftszeicchens." Gluckstadt:J.J. Augistin.

726 Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A.C.M., Levrard, B. 2004.
727 A long term numerical solution for the insolation quantities of the Earth. Astronomy &
728 Astrophysics. 428, 261-285.
729 Ledo, R.M.D., Colli, G.R. 2017. The historical connections between the Amazon
730 and the Atlantic Forest revisited. Journal of Biogeography. 44 (11), 2551-2563. DOI:
731 https://doi.org/10.1111/jbi.13049.

732 Ledru, M.-P., Mourguiart, P., Ceccantini, G., Turcq, B., Sifeddine, A. 2002.
733 Tropical climates in the game of two hemispheres revealed by abrupt climatic change.
734 Geology, 30, 275-278. DOI: https://doi.org/10.1130/0091-
735 7613(2002)030<0275:TCITGO>2.0.CO;2

736 Li, M., Hinnov, L., Kump, L. 2019. Acycle: Time-series analysis software for
737 paleoclimate research and education. Computers & Geosciences 127, 12-22. Doi:
738 https://doi.org/10.1016/j.cageo.2019.02.011

739 Lima, A.G.M., de Melo A.M.B.L. 1985. Atlas Geográfico do Estado da Paraíba.
740 Relevo. In Secretária da Educação; Governo do Estado da Paraíba; Universidade
741 Federal da Paraíba. João Pessoa (PB): Grafset. p.26-29.

742 Maher, L.J.J. 1972. Nomograms for computing 0.95 confidence limits of pollen
743 data. Review of Paleobotany and Palynology 13, 85-93.

744 Maher, L.J.J. 1981. Statistics for microfossil concentration measurements
745 employing samples spiked with marker grains. Review Palaeobotany and Palynology
746 32, 153-191.

747 Marchant, R., Almeida, L., Behling, H., Berrio, J.C., Bush, M., Cleef, A.,
748 Duivenvoorden, J., Kappelle, M., de Oliveira, P., de Oliveira-Filho, A.T., Lozano-
749 Garcia, S., Hooghiemstra, H., Ledru, M.-P., Ludlow-Wiechers, B., Markgraf, V.,
750 Mancini, V., Paez, M., Preto, A., Rangel, O., Salgado-Labouriau, M.L. 2002.
751 Distribution and ecology of parent pollen lodged within the Latin American Pollen
752 Database. Review of Palaeobotany and Palynology. 121, 1-75. DOI: 10.1016/S0034-
753 6667(02)00082-9
754 McConnachie, A.J., Strathie, L.W., Mersie, W., Gebrehiwot, L., Zewdie, K.,
755 Abdurehim, A., Abrha, B., Araya, T., Asaregew, F., Assefa, F., Gebre-Tsadik, R.,
756 Nigatu, L., Tadesse, B., Tana, T. 2011. Current and potential geographical distribution
757 of the invasive plant Parthenium hysterophorus (Asteraceae) in eastern and southern
758 Africa. Weed Research. 51(1):71–84. doi: 10.1111/j.1365-3180.2010.00820.x

759 McGee, D., Moreno-Chamarro, E., Green, B., Marshall, J., Galbraith, E.,
760 Bradtmiller, L. 2018. Hemispherically asymmetric trade wind changes as signatures of
761 past ITCZ shifts, Quaternary Science Reviews, 180, 214-228, ISSN 0277-3791. DOI:
762 https://doi.org/10.1016/j.quascirev.2017.11.020

763 Mulitza, S., Prange, M., Stuut, J.-B., Zabel, M., Dobeneck, T. von, Itambi, A.C.,
764 Nizou, J., Schulz, M., Wefer, G. 2008. Sahel megadroughts triggered by glacial
765 slowdowns of Atlantic meridional overturning. Paleoceanography, 23, p. PA4206.

766 Mulitza, S., Chiessi, C.M., Schefuß, E., Lippold, J., Wichmann, D., Antz, B.,
767 Mackensen, A., Pau, A., Prange, M., Rehfeld, K., Werner, M., Bickert, T., Frank, N.,
768 Kuhnert, H., Lynch stieglitz J., Portilho Ramos, R.C., Sawakuchi, AO., Schulz, M.,
769 Schwenk, T., Tiedemann, R., Vahlenkamp, M., Zhang, Y. 2017. Synchronous and
770 proportional deglacial changes in Atlantic meridional overturning and northeast
771 Brazilian precipitation. Paleoceanography. 32, 622-633. DOI:
772 https://doi.org/10.1002/2017PA003084.

773 Muhs, D.R. 2013. The geologic records of dust in the Quaternary. Aeolian
774 Research. Volume 9, Pages 3-48, ISSN 1875-9637, DOI:
775 https://doi.org/10.1016/j.aeolia.2012.08.001.

776 Nace, T.E., Baker, P.A., Dwyer, G.S., Silva, C.G., Rigsby, C.A., Burns, S.J.,
777 Giosan, L., Otto-Bliesner, B., Liu, Z., Zhu, J. 2014. The role of North Brazil Current
778 transport in the paleoclimate of the Brazilian Nordeste margin and paleoceanography of
779 the western tropical Atlantic during the late Quaternary. Palaeogeography, Palaeoclimatology, Palaeoecology. 415, 3-13. DOI: 780
781 https://doi.org/10.1016/j.palaeo.2014.05.030.

782 North Greenland Ice Core Project members. 2004. High-resolution record of Northern Hemisphere climate extending into the last interglacial period. Nature 783
784 431(7005):147-151.

785 Oliveira, R., Silva, A., Ribeiro, A., Araújo, J., Oliveira, O., Camacho, R. 2013. List of angiosperm species of the riparian vegetation of the Apodi-Mossoró River, Rio Grande do Norte, Brazil. Check List. 9 (4), 740-751. DOI: 786
787
788 https://doi.org/10.15560/9.4.740.

789 Pennington, R.T., Prado, D.E., Pendry, C.A. 2000. Neotropical seasonally dry forests and Quaternary vegetation changes. Journal of Biogeography. 27, 261-273.
790
791 DOI:10.1046/j.1365-2699.2000.00397.x

792 Pennington, R.T., Lewis, G.P., Ratter, J.A. 2006. An overview of the plant diversity, biogeography and conservation of neotropical savannas and seasonally dry forests. In: Pennington RT, Lewis GP, Ratter JA, editors. Neotropical Savannas and Seasonally Dry Forests: Plant Diversity, Biogeography, and Conservation. Boca Raton, FL: CRC Press; 793
794
795
796 pp. 1-29.

797 Pennington, R.T., Lavin, M., Oliveira-Filho, A. 2009. Woody plant diversity, evolution and ecology in the tropics: Perspectives from seasonally dry tropical forests. Annual Review of Ecology, Evolution, and Systematics. 40:437-457. DOI: 798
799 https://doi.org/10.1146/annurev.ecolsys.110308.120327

801 Petit, J.R., Jouzel, J., Raynaud, D., Barkov, N.I., Barnola, J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, M., Delaygue, G., Delmotte, M., Kotlyakov, V.M., Legrand, M., Lipenkov, V.Y., Lorius, C., P'epin, L., Ritz, C., Saltzman, E., Stievenard, M. 1999. 802
803
Climate and atmospheric history of the past 420000 years from the Vostok ice core, Antarctica. Nature. 399, 429–436. DOI: https://doi.org/10.1038/20859.

Piacsek, P., Behling, H., Gu, F., Venancio, I. M., Lessa, D.V.O., Belem, A., Albuquerque, A.L.S. 2021a. Changes in sea surface hydrography and productivity in the western equatorial Atlantic since the Last Interglacial. Palaeogeography, Palaeoclimatology, Palaeoecology. DOI: 10.1016/j.palaeo 2020 109952

Piacsek, P., Behling, H., Venancio, I. M., Ballalai, J. M., Nogueira, J., Albuquerque, A.L.S. 2021b. Reconstruction of vegetation and low latitude ocean-atmosphere dynamics of the past 130 kyr, based on south American montane pollen types. Global and Planetary Change. DOI: 10.1016/j.gloplacha.2021.103477

Pinaya, J.L.D., Cruz, F.W., Ceccantini, G.C.T., Pedro, L.P, Corrêa Pitman, N., Vemado, F., Lopez, S.M.A., Pereira, Filho A.J., Grohmann, C.H., Chiessi C.M., Stríkis, N.M., Horák-Terra, I., Pinaya, W.H.L., De Medeiros, V.B., Santos, R. De A., Akabane, T.K., Silva, M.A., Cheddadi, R., Bush, M., Henrot, J., François, L., Hambuckers, A., Boye, F., Carré, M., Coissac, E., Ficetola, F., Huang, K., Lézine, A-M., Nourelbait, M., Rhoujjati, A., Taberlet, P., Sarmiento, F., Abel-Schaad, D., Alba-Sánchez, F., Zheng, Z., de Oliveira, P.E. 2019. Brazilian montane rainforest expansion induced by Heinrich stadial 1 event. Scientific Reports. 9 (17912). DOI: https://doi.org/10.1038/s41598-019-53036-1.

Poorter, L. 2007. Are species adapted to their regeneration niche, adult niche, or both? The American Naturalist., 169, 433–442.

Por, F.D. 1992. Sooretama: the Atlantic rain forest of Brazil. SPB Academic Publishing. The Hague, p. 130.

Tardif, D., Toumoulin, A., Fluteau, F., Donnadieu, Y., Le Hir, G., Barbolini, N., Licht, A., Ladant, J.B., Sepulchre, P. Viovy, N., Hoorn, C., Dupont-Nivet, G. 2021.
829 Orbital variations as a major driver of climate and biome distribution during the
830 greenhouse to icehouse transition. Science Advances 7(43):eabh2819. DOI:
831 10.1126/sciadv.abh2819.

832 Reimer, P.J., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Ramsey, C.B.,
833 Buck, C.E., Cheng, H., Edwards, R.L., Friedrich, M., Grootes, P.M., Guilderson, T.P.,
834 Haflidason, H., Hajdas, I., Hatté, C., Heaton, T.J., Hoffmann, D.L., Hogg, A.G.,
835 Hughen, K.A., Kaiser, K.F., Kromer, B., Manning, S.W., Niu, M., Reimer, R.W.,
836 Richards, D.A., Scott, E.M. Southon, J.R., Staff, R.A., Turney, C.S.M., Van Der Plicht,
837 J. 2013. Int. Cal13 and Marine13 radiocarbon age calibration curves 0-50,000 years cal
838 BP. Radiocarbon. 55 (04), 1869-1887. DOI: https://doi.org/10.2458/azu_js_rc.55.16947.

839 Rhoades, C.C., Eckert, G. E., Coleman, D.C. 1998. Effect of pasture trees on soil
840 nitrogen and organic matter: implications for tropical montane forest restoration.
841 Restoration Ecology. 6, 262-270. DOI: 10.1046/j.1526-100X.1998.00639.x

842 Rühlemann, C., Frank, M., Hale, W., Mangini, A., Mulitza, S., Muller, P.J., Wefer,
843 G. 1996. Late Quaternary productivity changes in the western equatorial Atlantic:
844 evidence from 230Th-normalized carbonate and organic carbon accumulation rates.
845 Marine Geology. 135 (1-4), 127-152. https://doi.org/10.1016/S0025-3227(96)00048-5.

846 Santos, R.M., Oliveira-Filho, A.T., Eisenlohr, P.V., Queiroz, L.P., Cardoso, D.B.,
847 Rodal, M.J.N. 2012. Identity and relationships of the Arboreal Caatinga among other
848 floristic units of seasonally dry tropical forests (SDTFs) of north-eastern and central
849 Brazil. Ecology and Evolution. 2, 409-428. doi:10.1002/ece3.91

850 Shimizu, M.H., Anochi, J.A. Kayano, M.T. 2022. Precipitation patterns over
851 northern Brazil basins: climatology, trends, and associated mechanisms. Theoretical and
852 Applied Climatology. 147, 767-783. DOI: https://doi.org/10.1007/s00704-021-03841-4
Silveira, M.H.B., Mascarenhas, R., Cardoso, D., Batalha-Filho, H. 2019. Pleistocene Climatic Instability Drove the Historical Distribution of Forest Islands in the Northeastern Brazilian Atlantic Forest. Palaeogeography, Palaeoclimatology, Palaeoecology. 527, 67-76. DOI: https://doi.org/10.1016/j.palaeo.2019.04.028.

Spasojevic, M.J., Yablon, E.A., Oberle, B., Myers J.A. 2014. Ontogenetic trait variation influences tree community assembly across environmental gradients. Ecosphere, 5(10), 1-20.

Sterck, F., Markesteijn, L., Schieving, F., Poorter L. 2011. Functional traits determine trade-offs and niches in a tropical forest community. Proceedings of the National Academy of Sciences, 108(51), 20627-20632. DOI: 10.1073/pnas.1106950108

Stockmarr, J. 1971. Tablets with spores used in absolute pollen analysis. Pollen et Spores. 13(4), 615-621.

Stramma, L., Fischer, J., Reppin, J. 1995. The North Brazil Undercurrent. Deep-Sea Research I. 42 (5), 773-795. DOI: https://doi.org/10.1016/0967-0637(95)00014-W

Stríkis, N.M., Cruz, F.W., Barreto, E.A.S., Naughton, F., Vuille, M., Cheng, H., Voelker, A.H.L., Zhang, H., Karmann, I., Edwards, L., Auler, AS., Santos, R.V., Sales, H.R. 2018. South American monsoon response to iceberg discharge in the North Atlantic. The Proceedings of the National Academy of Sciences. 115 (15), 3788-3793. DOI: https://doi.org/10.1073/pnas.1717784115.

Subba Reddi, C., Reddi, N.S. 1986. Pollen production in some anemophilous angiosperms. Grana. 25 (1), 55-61. DOI: https://doi.org/10.1080/00173138609429933.

Sunderland, T., Apgaua, D., Baldauf, C., Blackie, R., Colfer, C., Cunningham, A.B., Dexter, K., Djoudi, H., Gautier, D., Gumbo, D., Ickowitz, A., Kassa, H., Parthasarathy, N., Pennington, R.T., Paumgarten, F., Pulla, S., Sola, P., Tng, D.Y.P., Waeber, O.,
877 Wilmé, L. 2015. Global dry forests: a prologue. International Forestry Review. 17(S2),
878 1-9. DOI:10.1505/146554815815834813

879 Utida, G., Cruz, F.W., Etourneau, J., Bouloubassi, I., Schefuß, E., Vuille, M.,
880 Novello, V.F., Prado, L.F., Sifeddine, A., Klein, V., Zular, A., Viana, J.C.C., Turcq, B.
881 2009. Tropical South Atlantic influence on northeastern Brazil precipitation and ITCZ
displacement during the past 2300 years. Scientific Reports. 9 (1698). DOI:
882 https://doi.org/10.1038/s41598-018-38003-6.
883

884 Van Bloem, S.J., Murphy, P.G., Lugo, A.E. 2004. TROPICAL FORESTS. Tropical
885 Dry Forests. Encyclopedia of Forest Sciences, Pages 1767-1775, ISBN 9780121451608.
886 DOI: https://doi.org/10.1016/B0-12-145160-7/00176-9.

887 Velloso, A.L., Sampaio, E.V.S.B., Pareyn, F.G.C. 2002. Ecorregiões propostas para
888 o Bioma caatinga. In: Recife, Associação Plantas do Nordeste. The Nature Conservancy
889 do Brasil, Instituto de Conservação Ambiental (76pp.).

890 Venancio, I.M., Mulitza, S., Govin, A., Santos, T.P., Lessa, D.O., Albuquerque,
891 A.L.S., Chiessi, C.M., Tiedemann, R., Vahlenkamp, M., Bitcket, T., Schulz, M. 2018.
892 Millennial- to orbital-scale responses of western equatorial Atlantic thermocline depth
to changes in the trade wind system since the Last Interglacial. Paleooceanography and
893 Paleoclimatology. 33 (12), 1490-1507. DOI: https://doi.org/10.1029/2018PA003437.
894

895 Waelbroek, C., Labeyrie, L., Michel, E., Duplessy, J.C., McManus, J.F., Lambeck,
896 K., Labracherie, M. 2002. Sea-level and deep water temperature changes derived from
897 benthic foraminifera isotopic records. Quaternary Science Reviews. 21 (1-3), 295-305.

898 Wang, X., Auler, A.S., Edwards, R.L., Cheng, H., Cristalli, P.S., Smart, P.L.,
899 Richards, D.A., Shen, C-C. 2004. Wet periods in northeastern Brazil over the past 210
900 kyr linked to distant climate anomalies. Nature. 432 (7018), 740-743. DOI:
901 https://doi.org/10.1038/nature03067
902 Whitmore, T.C. 1991. Tropical rain forest dynamics and its implications for
903 management. Rain Forest Regeneration and Management (eds. A. Gómez-Pompa, T.C.
904 Whitmore & M., Hadley), pp. 67–89. Parthenon Publishing, Lancaster, UK, and
905 UNESCO, Paris.

906 Wright, S.J., Kitajima, K., Kraft, N.J., Reich, P.B., Wright, I.J., Bunker, D.E.,
907 Engelbrecht, B.M. 2010. Functional traits and the growth-mortality trade-off in tropical
908 trees. Ecology, 91(12), 3664-3674. DOI: https://doi.org/10.1890/09-2335.1

909 Zhang, Y., Chiessi, C.M., Mulitza, S., Zabel, M., Trindade, R.I.F., Hollanda,
910 M.H.B.M., Dantas, E.L., Govin, A., Tiedemann, R., Wefer, G. 2015. Origin of
911 increased terrigenous supply to the NE South American continental margin during
912 Heinrich Stadial 1 and the Younger Dryas. Earth Planetary Science Letters. 432, 493-
913 500. DOI: https://doi.org/10.1016/j.epsl.2015.09.054.
<figure><img src="image_2.png" /></figure>

Figure 1: Map of the mean annual rainfall from 1991 to 2021 (CCKP, 2022) and the disposition of the modern terrestrial biomes discussed in this paper (IBGE, 2014). The black arrows illustrate the main routes of biotic interchange between the Amazon and the Atlantic rainforest (Por, 1992). The thickness of the arrows is related to the importance of the route. The map also shows the rainfall variability of biomes in NE Brazil from 1979 to 2013: Amazon rainforest (1847.9 mm ± 418.7 mm), *caatinga* (773.1 mm ± 212.5 mm), and *cerrado* (1196.6 mm ± 218.9 mm), Atlantic rainforest (1363.8 mm ± 217.0 mm) (Correia Filho *et al.*, 2019).
<figure><img src="image_3.png" /><figcaption>Figure 2: Topographical map of the study area. The red dot marks the location of the studied marine core GL-1248 (0° 55.2'S, 43° 24.1'W). The location of the previous marine sediment cores GeoB 16206-1 (Zhang et al., 2015), GeoB 16205-4 (Bouimetarhan et al., 2018); GeoB 3912-1/GeoB 3104-1 (Behling et al., 2000; Jennerjahn et al., 2004), and GeoB 3910-2 (Dupont et al., 2010) are shown by the yellow dots. The blue squares show the location of the palynological records covering the Holocene and the last glacial: 1) Icatu River peat-bog, (De Oliveira et al., 1999); 2) MA97-1, (Ledru et al., 2002); 3) Barra Velha, at Marajó Island, (Behling et al., 2004); 4) Pántano de Maurítia, (Hermanowski et al., 2012); 5) The location of the speleothem record from Toca da Boa Vista (Wang et al., 2004) is indicated by the black diamond. The red arrows on the Atlantic Ocean represent the warm surface currents North Equatorial Countercurrent (NECC), North Brazil Current (NBC), South Equatorial Current with central and southern branches (cSEC, and sSEC), and Brazil Current (BC). The white dashed line displays the southernmost position of the Intertropical Convergence Zone (ITCZ) during the end of Austral autumn (March-April) and the Austral winter (July-August). The black both sides' arrow indicates the location for the possibility to form coastal forest corridors connecting Amazonian and Atlantic rainforests through the coastal route of NE Brazil. The dashed line shows the hydrographical basin of the Parnaiba (~344 km²) in NE Brazil.</figcaption></figure>
<figure><img src="image_4.png" /><figcaption>Figure 3: (A) Pollen sum, the red line indicates the average of the sum of pollen and spores; (B) Pollen concentration (10⁶grains/cm³); (C) GL-1248 Sedimentation rate (cm/kyr) (Venancio et al., 2018); (D) Pollen influx (10⁶grains/cm²/kyr); (E) Sea Level (m) (Waelbroeck et al., 2002).</figcaption></figure>
<figure><img src="image_5.png" /><figcaption>Figure 4: Chart of the relative abundance of 12 pollen types of main groups of taxa (tropical dry forest, lowland rainforest, and wetland) along the marine core GL-1248. The total percentage of each pollen group (tropical dry forest, lowland rainforest, and wetland) are displayed on the right and the black line is related to their respective pollen concentrations. The pollen data of GL-1248 were previously addressed in Piacsek *et al.* (2021b).</figcaption></figure>
<figure><img src="image_6.png" /><figcaption>**Figure 5:** (A) Radiocarbon dating (yellow dots) and Tie-points (red squares) (Venancio *et al.*, 2018); (B) X-ray fluorescence (XRF) Ti/Ca ratio of the GL-1248 core (Venancio *et al.*, 2018); (C) XRF Fe/K ratio of GL-1248 (de Sousa *et al.*, 2021); (D) %Wetland group; (E) %Tropical dry forest group; (F) *Selaginella* spores; (G) %Lowland rainforest group; Shadings indicate the 95% confidence interval calculated after Maher (1972). The double-headed arrow indicates the transition from dry to wet, related to the Ti/Ca, Fe/K and wetland taxa. The Heinrich Stadials (HS) are marked in light blue, with the respective acronyms. The MIS 4 is marked in gray, the Younger Dryas (YD) and the other Stadials of the Early glacial (~70 - 115 kyr) and the last interglacial (MIS5e, ~115 -130 kyr) are highlighted in yellow.</figcaption></figure>
<figure><img src="image_7.png" /><figcaption>Figure 6: (A) Dome C temperature anomaly, ΔT [°C] (Petit et al., 1999); (B) Detrended lowland rainforest; (C) Lowland rainforest 23 kyr bandpass filter output; (D) Inverted axis of insolation 0° (March to May), black line (Laskar et al., 2004); (E) Detrended tropical dry forest; (F) Tropical dry forest 23 kyr bandpass filter output; (G) Obliquity orbit, black dotted line (Berger & Loutre, 1999); (H) Reflectance L* of Cariaco Basin (Deplazes et al., 2013); (I) %Tropical forest of Cariaco Basin (Gonzalez et al., 2008; Hessler et al., 2010); Shadings indicate the 95% confidence interval calculated after Maher (1972). The Heinrich Stadials (HS) are marked in light blue, with the respective acronyms. The MIS 4 is marked in gray, the Younger Dryas (YD) and the other Stadials of the early glacial (~70 - 115 kyr) and the last interglacial (MIS5e, ~115 -130 kyr). The 23 kyr cycles were extracted with LOESS bandpass filter using free Acycle software (Li et al., 2019).</figcaption></figure>
<figure><img src="image_8.png" /><figcaption>Figure 7: (A) Detrended pioneer trees of the tropical dry forest; (B) Detrended pioneer trees lowland rainforest; (C) Detrended secondary forest of the tropical dry forest; (D) Detrended secondary forest of lowland rainforest. The inverted axis of insolation 0° MAM for tropical dry forest (red line), and the insolation 0° MAM for lowland rainforest (blue line). The 23 kyr cycles were extracted with LOESS bandpass filter (black line) for each arboreal pollen group.</figcaption></figure>
<table><caption>Table 1 - The list of the most representative groups (wetland, lowland rainforest, and tropical dry forest) of pollen taxa identified in marine sediment core GL-1248. The pollen taxa are grouped according to their phytogeographical assignment based on De Oliveira *et al.* (1999), Behling *et al.* (2000), and Bouimetarhan *et al.* (2018).</caption><thead><tr><th>Wetland</th><th>Lowland rainforest</th><th>Tropical dry forest (caatinga and cerrado)</th></tr></thead><tbody><tr><td><ul><li>Cyperaceae,</li><li>Iridaceae,</li><li>utricularia (Lentibulariaceae),</li><li>Ludwigia (Onagraceae),</li><li>Polygonaceae</li></ul></td><td><ul><li>Alchornea (Euphorbiaceae),</li><li>Allophylus (Sapindaceae),</li><li>Arecaceae,</li><li>Banara (Flacourtiaceae),</li><li>Bombacaceae,</li><li>Cecropia (Urticaceae),</li><li>Celtis (Cannabaceae),</li><li>Cordia (Boraginaceae),</li><li>Curcubitaceae,</li><li>Dioclea (Fabaceae),</li><li>Doliocarpus type (Dilleniaceae),</li><li>Flacourtiaceae,</li><li>Gallesia (Phytolaccaceae),</li><li>Gordonia (Theaceae),</li><li>Hippocratea volubilis (Celastraceae),</li></ul></td><td><ul><li>Acanthaceae,</li><li>Aegiphila (Verbenaceae),</li><li>Alternanthera (Amaranthaceae),</li><li>Amaranthaceae/Chenopodiaceae,</li><li>Anacardiaceae,</li><li>Annonaceae,</li><li>Apocynaceae,</li><li>Asteraceae,</li><li>Bauhinia (Fabaceae),</li><li>Boraginaceae,</li><li>Borreria (Rubiaceae),</li><li>Byrsonima (Malpighiaceae),</li><li>Cactaceae,</li><li>Convolvulaceae,</li><li>Cuphea (Lythraceae),</li><li>Didymopanax (Araliaceae),</li><li>Faramae (Rubiaceae),</li><li>Gomphrena-Pfaffia type (Amaranthaceae),</li></ul></td></tr></tbody></table>
<table><thead><tr><th>Name</th><th>Structure</th><th>Succecion type</th></tr></thead><tbody><tr><td colspan="3" style="text-align: center; font-weight: bold;">Tropical dry forest</td></tr><tr><td>Annonaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Araliaceae <i>Didymopanax</i></td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Boranginaceae</td><td>Lianas</td><td>Pionner</td></tr><tr><td>Cactaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Convolvulaceae</td><td>Lianas</td><td>Pionner</td></tr><tr><td>Mimosaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Rubiaceae <i>Psychotria</i></td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Verbenaceae</td><td>Lianas</td><td>Pionner</td></tr><tr><td colspan="3" style="text-align: center; font-weight: bold;">Lowland rainforest</td></tr><tr><td>Arecaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Arecaceae <i>Mauritia</i></td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Bombacaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Boranginaceae <i>Cordia</i></td><td>Tree to herb</td><td>Pionner</td></tr><tr><td>Euphorbiaceae <i>Alchornea</i></td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Malpighiaceae</td><td>Shrubs</td><td>Pionner</td></tr><tr><td>Meliaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Myrtaceae</td><td>Trees</td><td>Pionner</td></tr><tr><td>Melastomataceae/ Combrataceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Phytolaccaceae <i>Gallesia</i></td><td>Trees</td><td>Pionner</td></tr><tr><td>Piperaceae <i>Piper</i></td><td>Trees</td><td>Pionner</td></tr><tr><td>Proteaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Rutaceae <i>Zanthoxylum</i></td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Salicaceae <i>Salix</i></td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Sterculiaceae</td><td>Trees and shrubs</td><td>Pionner</td></tr><tr><td>Ulmeaceae</td><td>Trees</td><td>Pionner</td></tr><tr><td>Urticaceae <i>Cecropia</i></td><td>Shrubs</td><td>Pionner</td></tr></tbody></table>
<table><caption>Table 2 – The ecological succession of the tree and shrub species from the dry forest and lowland rainforest groups, according to Gentry, 1993 and Marchant *et al.*, 2002.</caption><thead><tr><th>Name</th><th>Structure</th><th>Succecion type</th></tr></thead><tbody><tr><td colspan="3" style="text-align: center; font-weight: bold;">Tropical dry forest</td></tr><tr><td>Anacardiaceae</td><td>Trees and shrubs</td><td>Secondary forest</td></tr><tr><td>Apocynaceae</td><td>Trees</td><td>Secondary forest</td></tr><tr><td>Lythraceae</td><td>Shrubs</td><td>Secondary forest</td></tr><tr><td>Malpighiaceae</td><td>Shrubs</td><td>Secondary forest</td></tr><tr><td>Malvaceae</td><td>Trees and shrubs</td><td>Secondary forest</td></tr><tr><td>Rubiaceae</td><td>Trees and shrubs</td><td>Secondary forest</td></tr><tr><td>Vitaceae</td><td>Trees</td><td>Secondary forest</td></tr><tr><td colspan="3" style="text-align: center; font-weight: bold;">Lowland rainforest</td></tr><tr><td>Burseraceae</td><td>Protium</td><td>Secondary forest</td></tr><tr><td>Cannabaceae</td><td>Celtis</td><td>Secondary forest</td></tr><tr><td>Celastraceae</td><td>H. volubilis</td><td>Secondary forest</td></tr><tr><td>Curcubitaceae</td><td>Lianas</td><td>Secondary forest</td></tr><tr><td>Dilleniaceae</td><td>Doliocarpus</td><td>Secondary forest</td></tr><tr><td>Flacourtiaceae</td><td>Trees and shrubs</td><td>Secondary forest</td></tr><tr><td>Menispermaceae</td><td>Epiphyte</td><td>Secondary forest</td></tr><tr><td>Moraceae - Urticaceae</td><td>Trees and shrubs</td><td>Secondary forest</td></tr><tr><td>Piperaceae</td><td>Shrubs or epiphyte</td><td>Secondary forest</td></tr><tr><td>Sapindaceae</td><td>Allophylus</td><td>Secondary forest</td></tr><tr><td>Solanaceae</td><td>Solanum</td><td>Secondary forest</td></tr><tr><td>Symphonia</td><td>Globulifera</td><td>Secondary forest</td></tr><tr><td>Theaceae</td><td>Gordonia</td><td>Secondary forest</td></tr></tbody></table>