Trait differences between animals that interact with
megafaunal fruits and animals that don’t
Dudink, R. J. M.
Supervisors: Dracxler, C. & W. D. Kissling
Abstract
A key interaction in the tropics is frugivory, with up to 90% of the tropical trees and shrubs depending on frugivores for seed dispersal. In this interaction, two forms of trait matching can emerge; size matching and matching based on foraging behaviour, since animal mobility directly influences fruit accessibility. In Neotropical palm-frugivore interactions it has been shown that there is a mismatch between frugivore body size and palm fruit size, which may be caused by the extinction of the megafauna (herbivores with a body mass over 1000 kg) at the end of the Pleistocene. Some palms produce large fruits (>4 cm), that seem to be adapted to the interaction with the extinct megafauna. Contemporary animals like scatter hoarding rodents and parrots do interact with those fruits, often by carrying them instead of swallowing. We aim to investigate which animal traits may allow for the interaction between those contemporary animals and megafaunal fruits to take place. This study compares the differences between animals that do interact with megafaunal fruits and animals that have not been recorded to do so. Four frugivory relevant traits were compared; body size, foraging stratum, dispersal mode and degree of frugivory. This was done by first combining a palm-frugivore interaction dataset with palm traits for classification of non-megafaunal and megafaunal palm species and then combining it with animal trait data. While interaction records indicate that a variety of animals interact with megafaunal fruits, herein we show that these animals have a higher body mass, often forage on the ground and disperse seeds ectozoochorically. This indicates that specific traits allow frugivores to interact with megafaunal fruits. Larger animals are also the main target of the ongoing defaunation, showing a new threat to the megafaunal palm species.
Keywords
1 | Introduction
One of the key plant-animal interactions in the tropics is frugivory. It is estimated that up to 90% of the tropical trees and shrubs depend on their interaction with frugivores for seed dispersal (Fleming et al., 1987; Jordano, 2014). Seed dispersal is important for plants to keep populations genetically connected and to allow plants to colonize new areas (Trakhtenbrot et al., 2005). In this interaction, the functional traits of the interaction partners often show trait-matching. Those matches can generally be classified in two types; plant-animal size matching and matching related to foraging behaviour of the animal (Bernder et al., 2018). Size matching is well known in plant-frugivore interactions, since gape size (correlated with body size) determines which fruits an animal can or cannot ingest (Jordano, 2014; Onstein et al., 2017), which on its turn puts a selective pressure on the fruit size that plants produce (Lord, 2004). Matching related to animal foraging behaviour often relates to animal mobility and the location of the fruits on the plant. For example, plant height matches with bird wing shape (Bender et al., 2018), which is related to the mobility of the bird in the dense understory.
Among fruiting trees in the tropics, palms are a well-represented family and many palm species are hyperdominant in the plant community (ter Steege et al., 2013). The palm family consists of around 2500 species in 184 genera worldwide (Couvreur & Baker, 2013), with about 550 species in the Neotropics (Kreft et al., 2005). Palms are keystone species for the frugivorous community (Genini et al., 2009), producing fruits that are typically dispersed by animals (Onstein et al., 2017). Growing from the understorey to the canopy of the forest, palms produce various types of fruits with sizes ranging from 0.5 cm to 35 cm. The interactions between palms and frugivores has previously been studied in research by Muñoz et al. (2019). In this study, size matching was found in for the Afrotropics, but the match lacked for the Neotropics. A possible explanation for this result is that large palm fruits were primarily consumed and dispersed by now extinct megafaunal animals. Their extinction may have led to the loss of size matching in the Neotropics.
Megafauna, herbivores with a body mass over 1000 kg (Guimarães Jr. et al., 2008), used to roam the Neotropical forests (Janzen & Martin, 1982; Onstein et al., 2018), but 83% of the South American megafauna went extinct at the end of the Pleistocene (Janzen & Martin, 1982; Barlow et al., 2001; Barnosky et al., 2014). Numerous palm species seem to be adapted to the interaction with those large herbivores, instead of the modern-day frugivores. The link between the anachronistic fruits and the extinct megafauna was first described by Janzen & Martin (1982) as the megafaunal syndrome. Guimarães Jr. et al. (2008) later gave a definition to the fruits of this syndrome and described two types; type 1 includes fleshy fruits larger than 4 cm in diameter with up to 5 big seeds and type 2 includes fleshy fruits larger than 10 cm in diameter with over 100 seeds. Their definition was based on the definitions of fruits eaten by African elephants, a good model species due to its size, ecomorphology and dietary habits. Worldwide, 12% of the palms produce fruits that fit this definition of megafaunal fruits (Onstein et al., 2017). Many also have large spines that can’t be explained by an interaction with extant animals, but only by the interaction with the extinct megafauna (Janzen & Martin, 1982).
By interacting with megafauna, palms could escape the seed size constraint for dispersal (Guimarães Jr. et al., 2008), which gives them a survival advantage over species with smaller seeds (Moles & Westoby 2004). Only animals without a size constraint for fruits and seeds can extensively disperse seeds larger than the current limit of 3.5-4.0 cm in the Neotropics (Guimarães Jr. et al., 2008). Large herbivores also generally have a bigger range and would disperse seeds further from the mother plant (Pires et al., 2017), often depositing seeds in suitable sites for germination, therefore increasing seedling survival (Jordano et al., 2007). With the loss off effective dispersal, populations will be threatened by demographic, environmental and genetic stochasticity (Trakhtenbrot et al., 2005). New World megafaunal palms show a higher extinction rate since the onset of the Quaternary, likely caused by the loss of their main dispersers (Onstein et al., 2018). Plants with megafaunal fruits may be increasingly lost due to the ongoing defaunation, because the remaining large frugivores are among the most hunted animals in the tropics (Peres, 2000). This may on its turn have consequences for ecosystem functions, like carbon storage (Bello et al., 2015).
The hypothesis that Neotropical large-seeded palms have lost their primary dispersers in the late Pleistocene is counterpointed by evidence that contemporary animals interact with megafaunal fruit palms and have taken over the role of primary dispersers of the seeds (Jansen et al. 2012, Janzen & Martin 1982, Tella et al. 2020, Blanco et al. 2019). While only a few animals, like tapirs or livestock, are able to disperse the seeds of megafaunal fruits by endozoochory, several animals can disperse large palm seeds by carrying the fruit in their beaks or mouths (ectozoochory), a dispersal mode that does not involve seeds passing by animal’s gut, and therefore might be ruled by other traits than size. This way extant animals may have contributed to the persistence of megafaunal palms in the Neotropics after the megafauna went extinct. Scatter hoarding rodents are an example of this (Jansen et al., 2012). Instead of ingesting large palm fruits, scatter hoarding rodents can cache seeds for later consumption by carrying fruits in their mouth, dispersing seeds at long distances and contributing to seedling establishment when seeds are not recovered (Jansen et al. 2012). A recent study has also highlighted the role of macaw species as seed dispersers of
megafaunal seeds (Tella et al., 2020). While also being seed predators, they can carry the fruits to distant patches for handling and consumption, often dropping undamaged seeds on the ground while eating and therefore contributing to long distance dispersal. The macaw species in this study were among the largest macaw species in the Neotropics and the decision to move to distant patches for consumption could depend on fruit accessibility and macaw morphology (Tella et al., 2020).
This study aims to compare the differences in traits, relevant to the interaction with megafaunal fruits, between the modern animals that interact with the megafaunal fruits and the ones that have not been observed to do so in the Neotropics. Herein, four different animal traits were analysed; body mass, foraging stratum, dispersal mode (the way an animal disperses the seeds, i.e. endozoochory or ectozoochory) and degree of frugivory (how much of the diet consists of fruits and/or seeds). Body mass is the first most obvious trait to compare, since the megafaunal fruits are adapted to the large extinct frugivores. Usually, the relationship between body size and fruit size should lead to a higher body mass among animals that disperse megafaunal fruits. However, the loss of the megafauna may have caused this relation to be lost, which leads to the expectation that there will be no difference in body mass between the group that does and the group that doesn’t disperse megafaunal fruits. We also expect that the use of foraging strata will differ between the two groups. Since palm with smaller fruits are more common in the understory (Onstein et al., 2017), the expectation is that the animals interacting with megafaunal fruits forage more in the canopy. Regarding dispersal mode, we expect a clear difference between the two groups, with a prevalence of ectozoochory as dispersal mode of species interacting with megafaunal fruits, since only few extant animals are able to ingest entire megafaunal fruits (i.e. endozoochory). A higher degree of frugivory is expected among animals interacting with megafaunal fruits, since small fruits are easy to find, ingest and digest and many animals including species not adapted to frugivory can eat small fruits (Corlett, 1998). Larger fruits would require adaptations, so only the specialized animals should be able to eat megafaunal fruits.
2 | Methods 2.1 | Workflow
Workflow for data compilation and analysis can be seen in figure 1. Species level interaction data between frugivores and palms in the Neotropics was gathered from an unpublished dataset (Caroline Dracxler, unpublished).
Figure 1 Workflow for data compilation and analysis. White boxes indicate steps for the research, blue boxes indicate sources and green boxes indicate statistical tests used to compare the traits between the two groups.
2.2 | Classification of non-megafaunal and megafaunal palm species
For the classification of megafaunal palm species, each palm species included in the palm-frugivore interaction dataset was classified as either megafaunal or non-megafaunal species using the definition from Guimarães Jr. et al. (2008); fleshy fruits larger than 4 cm in diameter, containing up to 5 large seeds. The average fruit width was used from Palmtraits 1.0 (Kissling et al., 2019), supplemented with additional literature for missing values, and combined with the palm-frugivore interaction dataset. Then the dataset was split into two groups, where megafaunal fruits are
the fruits with an average fruit width larger or equal to 4 cm and non-megafaunal fruits the fruits with an average fruit width smaller than 4 cm. Among palms, no fruits are produced that have more than 5 seeds, so this criterium is already met. In addition to average fruit width, trait values for the maximum stem height and whether the palm is an understorey or canopy palm were also taken from PalmTraits1.0 (Kissling et al., 2019) and supplemented by additional literature for missing values. This was used to test for differences in fruit accessibility between non-megafaunal and non-megafaunal palms. Regarding the frugivores, species interacting with both non-non-megafaunal and megafaunal fruits were put in the megafaunal group for the analysis, since it shows that they are able to interact with megafaunal fruits.
2.3 | Compilation of animal trait data
Body mass (continuous) data came from EltonTraits 1.0 (Wilman et al., 2014). Foraging stratum (categorical) data also came from EltonTraits1.0 (Wilman et al., 2014), but had to be transformed into new categorical variables to harmonize the data. For this, three categories were used; ground, midhigh and canopy. For mammals, for which the foraging strata are categorized into marine, ground, scansorial, arboreal and aerial in EltonTraits1.0 (Wilman et al., 2014), the harmonisation was done using literature to find the stratum that a species uses the most. For birds, which have a percentage use of each foraging stratum (water-below surface, water-around surface, ground, understorey, midhigh, canopy and aerial) in EltonTraits1.0 (Wilman et al., 2014), species were first classed into the categories based on the foraging stratum used the most and when species used certain strata in same percentages, the classification was done based on additional literature. Dispersal mode (categorial) data is based on the way species disperse the fruits and seeds (endozoochory or ectozoochory) and comes from the palm-frugivore interaction dataset (Caroline Dracxler, unpublished). In the palm-frugivore interaction dataset the dispersal mode is classified to interaction level, meaning some species can have both endozoochory and ectozoochory as dispersal mode due to their interactions with multiple palm fruits. Those species were classed as dual, meaning the dispersal mode was categorized into 3 categories; endozoochory, ectozoochory and dual. For some species the dispersal mode could not be classified because they either don’t disperse the seeds or no data was available on the interaction. Those species were excluded from our data analysis. The degree of frugivory (proportional) data is based on the percentage of fruits and seeds in the diet of the animal, which came from EltonTraits 1.0 (Wilman et al., 2014). For the species that had 0% of fruits and 0% of seeds in their diet according to EltonTraits1.0 (Wilman et al., 2014), literature was used to specify the amount of fruits of seeds in their diet. This has been done because their presence in the palm-frugivore interaction dataset shows that they do have either some fruit or seed in their diet. For some of those species quantitative data was not available, so qualitative data was used to estimate the percentage of fruits or seeds in the diet using a set protocol. When diet items were listed as equally important, it was taken as a proportion of the total items listed. When words like “occasionally include” and “also includes” were used to describe the part of the diet, 10% was taken as the percentage of that item in the diet. The minimum degree of frugivory used is 0.1, since the minimum percentage of fruit or seeds in the diet in Eltontraits1.0 (Wilman et al., 2014) is 10%. Data manipulation has been done using the package R packages dplyr (Wickham et al., 2019) and tibble (Müller & Wickham, 2020).
2.4 | Data analysis
To test whether the two groups differ in the four traits mentioned above, the two groups were compared for each trait separately. Each species contributes only once to the group values for each of the traits. For body mass and degree of frugivory, a two-sample Wilcoxon test was used to compare the medians of both groups. For the other two traits, foraging stratum and dispersal mode, a Chi-square test was used to compare the groups. Data compilation and analysis was done using R studio version 3.6.1. The packages ggplot2 (Wickham, 2016) and ggpubr (Kassambara, 2020) were used for the graphical visualisation.
3 | Results
3.1 | Classification of non-megafaunal and megafaunal palm species
The final dataset contains 2799 pairwise interactions, containing 132 palm species and 402 frugivore species with 224 birds and 178 mammals. Classification of palm species resulted in 2355 interactions containing 113 palm species classified as non-megafaunal and 441 interactions containing 17 palm species classified as megafaunal. No significant differences were found between the two groups regarding the maximum stem height of the palms (Wilcoxon test, W = 1085.5, p-value = 0.3428) and the proportion of understorey and canopy palms (Fisher’s exact test, p-value = 1). A summary of palm and frugivore species in each group in the dataset can be found in Table 1.
Table 1 Summary of palm and frugivore species in each of the interaction groups (non-megafaunal and megafaunal) in the dataset. Non-megafaunal and megafaunal refer to the groups created by classifying palm species.
Non-megafaunal Megafaunal
Palm genera 41 8
Palm species 113 17
Average fruit width (cm) 1.81 6.66
Average maximum stem height (m) 12.88 15.68
Frugivore genera 204 79
Frugivore species 279 123
Birds 186 38
Mammals 93 85
3.2 | Compilation of animal trait data
Generally, data coverage was high except for the species coverage for the dispersal mode (Table 2). However, the proportions of mammals and birds in each group was similar to the proportions seen in the full dataset. The composition of each group regarding the class of the frugivores differs significantly (Chi-square test, p-value = 5.948e-11). Proportionally, more birds than mammals interact with non-megafaunal palm fruits and more mammals than birds interact with megafaunal fruits (Table 3). Mammals are divided equally between the two groups. Among birds, the majority interacts with non-megafaunal fruits.
Table 2 Interaction and species coverage per trait in the final dataset. Interaction coverage refers to the amount of interactions and percentage of the total interactions covered by the trait values. Species coverage refers to the amount species and percentage of the total species covered by the trait values.
Trait Interaction coverage #(%) Species coverage #(%)
Body mass 2792 (99.75) 398 (99%)
Foraging stratum 2799 (100%) 402 (100%)
Dispersal mode 2473 (88.35%) 226 (56.22%)
Degree of frugivory 2793 (99.79%) 399 (99.25%)
Table 3 Proportion of species of each frugivore class (birds and mammals) interacting with either non-megafaunal or megafaunal palm fruits.
Birds Mammals
Non-megafaunal 0.463 0.231
Megafaunal 0.095 0.211
3.3 | Trait comparison
For most of the analysed traits, the frugivores interacting with megafaunal fruits differed from the species that have not been recorded to do so (Figures 2-6). The median body mass of the animals interacting with megafaunal fruits is significantly higher than the median body mass of the animals that don’t interact with megafaunal fruits (Wilcoxon test, W = 10206, p-value = 5.410e-10; Figure 2). The difference in group composition might however influence this result, since mammals are heavier than birds and the megafaunal group consists of more mammals. Therefore the difference in body mass was also tested for each frugivore class separately (Figure 3). The difference in median body mass remains significant after splitting by frugivore class (Wilcoxon test, bird: W = 4678, p-value = 0.0013, mammals: W = 4524, p-value = 0.0350).
Figure 2 Log-transformed body mass values for the frugivore species interacting with either the non-megafaunal or the megafaunal palm fruits. Boxplots show the median, interquartile range and minimum and maximum values. Body mass significantly differs between the two groups (Wilcoxon test, W = 10206, p-value = 5.401e-10).
Figure 3 Log-transformed body mass values for the frugivore species interacting with either the non-megafaunal or the megafaunal palm fruits, split based on frugivore class. Boxplots show the median, interquartile range and minimum and maximum values. Body mass differs significantly between non-megafaunal and megafaunal species for both birds (Wilcoxon test, W = 4678, p-value = 0.0013) and mammals (Wilcoxon test, W = 4524, p-value = 0.0350).
The use of the three foraging stratum categories, ground, midhigh and canopy, differs significantly between the two groups (Chi-square test, ꭓ2
= 7.0659, p-value = 0.0292; Figure 4). While the proportion of species foraging in the canopy is similar, the animals interacting with non-megafaunal fruits forage more in the midhigh stratum and the animals interacting with megafaunal fruits forage more on the ground.
Figure 4 Proportions of species using the three different foraging stratum categories (Canopy, Midhigh and Ground) for the frugivore species interacting with either the non-megafaunal or the megafaunal palm fruits. The use of foraging strata significant differs between the two groups (Chi-square test, ꭓ2 = 7.0659, p-value = 0.0292).
Animals that interact with non-megafaunal fruits disperse fruits and seeds mostly by endozoochory and the animals interacting with megafaunal fruits disperse the seeds more often by ectozoochory (Chi-square test, ꭓ2 = 78.31, p-value
= 2.2e-16; Figure 5).
Figure 5 Proportions of species using the three different dispersal mode categories (endozoochory, ectozoochory and dual) for the frugivore species interacting with either the non-megafaunal or the megafaunal palm fruits. The use of the different dispersal modes significantly differs between the two groups (Chi-square test, ꭓ2 = 78.31, p-value = 2.2e-16).
For the animals interacting with non-megafaunal fruits, an average degree of frugivory of 0.54 ± 0.28 (±SD) was found and for the animals interacting with megafaunal fruits and average degree of frugivory of 0.50 ± 0.26 (±SD) was found (Figure 6). The difference between the two groups was not significant (Wilcoxon test, W = 18497, p-value = 0.1111).
Figure 6 Degree of frugivory for the frugivore species interacting with either the non-megafaunal or the megafaunal palm fruits. Boxplots show the median, interquartile range and minimum and maximum value. The is no significant difference between the two groups (Wilcoxon test, W = 18497, p-value = 0.1111).
4 | Discussion
While megafaunal palms have probably lost their main dispersers at the end of the Pleistocene, many studies have shown modern animals do interact with those palms and can effectively disperse their seeds (Jansen et al., 2012; Blanco et al.,2019; Tella et al., 2020). Our results indicate that there is a difference in frugivory relevant traits between animals that interact with megafaunal fruits and animals that have not been recorded to do so. While interaction records confirm that a wide variety of animals interact with megafaunal fruits, we show that species interacting with megafaunal fruits have a higher body mass, often forage on the ground and disperse the fruits and seeds ectozoochorically. We also provide evidence that, proportionally, more mammals interact with megafaunal fruits than birds.
The higher body mass among animals that interact with megafaunal fruits may be caused by a form of size matching between the palm fruits and the frugivores interacting with them. While this match might not have been caused by adaptation of the extant species in the interaction, we show that frugivores may still need a larger size to be able to interact with the megafaunal fruits. Our result seem to go against a result found by Muñoz et al. (2019), where no size matching was found between palms and frugivores in the Neotropics. Their research did find size matching in the Afrotropics, where megafaunal is still present.
The difference in foraging strata used by the two groups can be explained by a possible adaptation of megafaunal fruits to their interaction with the extinct megafauna. Many of the megafaunal fruits fall of the trees when they are ripe or even before they are ripe, which is a behavioural adaptation of plants that interact with ground-foraging frugivores (Janzen & Martin, 1982). Therefore, the extant frugivores interacting with those fruits may also most often find the megafaunal fruits on the ground. Besides, some of the contemporary dispersers of megafaunal fruits were likely secondary dispersers when the megafauna were still present (Jansen et al., 2012). In this substitution hypothesis, many scatter hoarding rodents play a role and these rodents are ground foragers.
The difference in dispersal modes between the interaction groups is likely caused by the smaller size of the extant frugivores that interact with the megafaunal fruits. Very few extant frugivores are able to ingest the large megafaunal fruits, which means their dispersal mode for megafaunal fruits will be limited to ectozoochory. This result follows one of the characteristics of megafaunal fruits proposed by Guimarães et al. (2008), which states that no extant frugivore (except tapirs and livestock) are able to disperse megafaunal fruits via endozoochory. A recent study by Blanco et al. (2019) on the dispersal of 6 palm species, 5 of which that could be classified as megafaunal palm species, found that ectozoochory is the main mode of dispersal for species that disperse the seeds of those palms. The primary dispersers of the 6 palms were found to be mainly parrots and monkeys, which take the fruits from the palms and
carry them to a different location for consumption. From below that perch, secondary dispersers, often rodents, act on the fallen fruits and seeds for further dispersal.
The lack of difference in degree of frugivory found between the two groups contradicts our expectations. Species that are not specially adapted to frugivory were found among the animals interacting with megafaunal fruits instead of only in the group of animals that only interact with non-megafaunal fruits. Examples of those species are Caracara plancus, a bird of prey, and Chrysocyon brachyurus, a canid, which shows that species that are adapted to other diets than frugivory are able to eat megafaunal fruits. Another example of a species with a low degree of frugivory that interacts with megafaunal fruits is Pecari tajacu. This low degree of frugivory is found because the diet of Pecari tajacu is very diverse, which makes fruits a small part of the diet. The many interactions of Pecari tajacu with megafaunal fruits shows that it can eat those fruits quite well, while still having a low degree of frugivory. Another explanation for the lack of difference in degree of frugivory could be that degree of frugivory takes fruits and seeds together, while these may differ when looked at separately. Larger seeds are eaten more often by mammals than small seeds (Paine & Beck, 2007). This difference may be lost when fruits and seeds are combined for the degree of frugivory.
The dataset also shows that proportionally, more mammals interact with megafaunal fruits and more birds interact with non-megafaunal fruits. This may be due to the adaptations of the megafaunal palm fruits to the megafauna, since most of the megafauna consisted of herbivorous or browsing mammals. It is also in line with a result from the study by Muñoz et al. (2019), which showed that mammalian frugivores tend to disperse larger palm fruits than birds. There is however a limitation to the dataset regarding the frugivores in the interactions. Our dataset only contains birds and mammals, while the frugivorous community of the Neotropics also includes other animals like reptiles, fish and insects. For this study we wanted to focus on birds and mammals, since they are the main dispersers of palm seeds in the Neotropics (Muñoz et al., 2019).
While the megafaunal palm species probably lost their main dispersers at the end of the Pleistocene, they were able to survive for the following 10.000 years. For their survival, secondary dispersers that took over the role of the primary dispersers probably played an important role (Guimarães et al., 2008; Jansen et al., 2012). The size difference found between the animals that interact with the megafaunal fruits and the ones that have not been recorded to do so shows a possible threat to the megafaunal palm species. The ongoing fast-paced defaunation of the tropics is mainly targeted at the large bodied animals (Peres, 2000; Dirzo et al., 2014). With more large bodied animals disappearing from the interactions with megafaunal palm species, the survival of those palms will be further threatened. It will cause a decrease in the amount of seeds successfully dispersed away from the mother plant and negatively impact palm demography and genetic structure of populations (Guimarães et al., 2008). These processes have already been measured in megafaunal palm species, with New World megafaunal palms showing a higher rate of extinction since the onset of the Quaternary (Onstein et al., 2018), likely due to the loss of their main dispersers. Future research could focus on more species, both palms and frugivores, to see whether the relations found in this study hold. The megafaunal fruits syndrome is extensively represented in other plant families, like Fabaceae, Malvaceae and Sapotaceae and whether the trait differences between animals interacting with megafaunal fruits and animals that have not been recorded to do so are the same for those plant families remains to be studied. This will require more extensive data collection and compilation. It may also focus on more traits to compare the animals that interact with megafaunal fruits and the ones that have not been recorded to do so. There may be more traits that differ between the two groups, like outcome of the interaction and day range of the frugivore for example. Traits that could determine whether the dispersal and dispersal effectiveness of the megafaunal fruits differs from the dispersal of non-megafaunal fruits.
This research shows that the traits of the frugivores interacting with megafaunal fruits differs from the traits of the frugivores that have not been recorded to do so. For the survival of certain groups of plants, it is important to understand anachronistic adaptations like the megafaunal fruit syndrome and the present-day species in the interactions to know the impact and consequences of the ongoing defaunation on the plant-animal communities.
Acknowledgements
I would like to thank Caroline Dracxler for providing the palm-frugivore dataset which allowed me to do this research and for her guidance through the project. I would also like to Daniel Kissling for his guidance through the project.
Data accessibility
Palm-frugivore interaction data and trait values compiled in this research will not be made accessible, because a large part of the final dataset comes from ongoing research by Caroline Dracxler.
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