The ghost fruits of Madagascar: Identifying dysfunctional seed dispersal in Madagascar's endemic flora

Albert-Daviaud, Aurélie; Buerki, Sven; Onjalalaina, Guy E.; Perillo, Sarah; Rabarijaona, Romer Narindra; Razafindratsima, Onja H.; Sato, Hiroki; Valenta, Kim; Wright, Patricia C.; Stuppy, Wolfgang

doi:10.1016/j.biocon.2020.108438

Cited by 26 publications

(24 citation statements)

References 45 publications

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“…Southwest Madagascar is inhabited by several tree species that rely on large-bodied animals for seed dispersal (e.g., species of Adansonia, Didiereaceae, Arecaceae) (Albert-Daviaud et al, 2020). Remnant lemur species, introduced bushpigs, and people may continue to disperse endemic seeds, yet multiple plant taxa are considered to have been "orphaned" by the extinction of their seed dispersers (Federman et al, 2016).…”

Section: Legacy Of Megafauna Extinctionmentioning

confidence: 99%

Influence of Late Holocene Climate Change and Human Land Use on Terrestrial and Aquatic Ecosystems in Southwest Madagascar

et al. 2021

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Madagascar’s biota underwent substantial change following human colonization of the island in the Late Holocene. The timing of human arrival and its role in the extinction of megafauna have received considerable attention. However, the impacts of human activities on regional ecosystems remain poorly studied. Here, we focus on reconstructing changes in the composition of terrestrial and aquatic ecosystems to evaluate the impact of human land use and climate variability. We conducted a paleoenvironmental study, using a sediment record that spans the last ∼1,145 years, collected from a lakebed in the Namonte Basin of southwest Madagascar. We examined physical (X-ray fluorescence and stratigraphy) and biotic indicators (pollen, diatoms and micro- and macro-charcoal particles) to infer terrestrial and aquatic ecosystem change. The fossil pollen data indicate that composition of grasslands and dry deciduous forest in the region remained relatively stable during an arid event associated with northward displacement of the Intertropical Convergence Zone (ITCZ) between ∼1,145 and 555 calibrated calendar years before present (cal yr BP). Charcoal particles indicate that widespread fires occurred in the region, resulting from a combination of climate drivers and human agency during the entire span covered by the paleorecord. Following settlement by pastoral communities and the disappearance of endemic megafauna ∼1,000 cal yr BP, grasslands expanded and the abundance of trees that rely on large animals for seed dispersal gradually declined. A reduction in the abundance of pollen taxa characteristic of dry forest coincided with an abrupt increase in charcoal particles between ∼230 and 35 cal yr BP, when agro-pastoral communities immigrated into the region. Deforestation and soil erosion, indicated by a relatively rapid sedimentation rate and high K/Zr and Fe/Zr, intensified between 180 and 70 cal yr BP and caused a consequent increase in lake turbidity, resulting in more rapid turnover of the aquatic diatom community. Land use and ongoing climate change have continued to transform local terrestrial and freshwater ecosystems during the last ∼70 years. The current composition of terrestrial and aquatic ecosystems reflects the legacy of extinction of native biota, invasion of exotic species, and diminished use of traditional land management practices.

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Section: Legacy Of Megafauna Extinctionmentioning

confidence: 99%

Influence of Late Holocene Climate Change and Human Land Use on Terrestrial and Aquatic Ecosystems in Southwest Madagascar

et al. 2021

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“…Interestingly, 48% of the animals that we observed feeding in the C. pentandra trees are known to be important seed dispersers (Razafindratsima 2014;Albert-Daviaud et al 2018;Albert-Daviaud et al 2020;Ramananjato et al 2020;Hending et al pers. comm., 2019).…”

mentioning

confidence: 81%

The kapok tree (Ceiba pentandra (L.) Gaertn, Malvaceae) as a food source for native vertebrate species during times of resource scarcity and its potential for reforestation in Madagascar

et al. 2021

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Reforestation in Madagascar often relies on a few tree species with known properties. Species selection may consider aspects like human use, growth characteristics and animal use. Here, we investigated the use of the kapok tree (Ceiba pentandra) as a food source for vertebrates during the dry season in North West Madagascar. We observed 21 native vertebrate species (five lemurs, five bats and 11 birds) feed on or within C. pentandra during this period of low food availability, 48% of which are known seed dispersers. As a fast-growing species, C. pentandra may therefore be suitable for inclusion in reforestation and forest restoration efforts to facilitate seed dispersal, natural forest regeneration and animal movement between adjacent forest fragments.

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“…These traits are especially relevant for the foraging activity by frugivores, depending on their gape width, body size constraints and activity in certain forest strata (Jordano 1995, Muller‐Landau et al 2008, Thomson et al 2011). We therefore collated maximum stem height and average fruit length and width from the PalmTraits 1.0 database (Kissling et al 2019), and average seed length and width from Albert‐Daviaud et al (2020). Because stem height and fruit size values were not available for all the 165 Malagasy palm species from the PalmTraits 1.0 database, we imputed the missing data by phylogenetic data imputation with the R package ‘Rphylopars' (Goolsby et al 2017).…”

Section: Methodsmentioning

confidence: 99%

Megafrugivores as fading shadows of the past: extant frugivores and the abiotic environment as the most important determinants of the distribution of palms in Madagascar

et al. 2022

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The extinction of all Madagascar's megafrugivores ca 1000 years ago, may have left its signature on the current distribution of vertebrate-dispersed plants across the island, due to the loss of effective seed dispersal. In this study, we dissect the roles of extinct and extant frugivore distributions, abiotic variables, human impact and spatial predictors on the compositional turnover, or beta-diversity, of palm (Arecaceae) species and their dispersal-related traits across 40 assemblages in Madagascar. Variation partitioning showed that palm beta-diversity is mostly shaped by the distribution of extant frugivores (eight lemur, three bird, two rodent and one bat species) and the abiotic environment (e.g. forest cover, slope and temperature), and to a lesser extent by the distribution of extinct megafrugivores (several giant lemur and elephant bird species). However, the contribution of these variables differed between dry western assemblages and wet eastern assemblages, with a more prominent role, albeit still small, of extinct megafrugivores in the west. These results suggest that palm distributions in the dry west of Madagascar, where megafrugivores were probably most abundant in the past, still show signatures of past interactions. With a fourth-corner analysis we observed that the distribution of palm species with relatively large fruits and seeds was negatively associated with frugivore richness of both past and present communities and home range sizes of extant mammalian frugivores. This suggests that palm species with relatively large fruits tend to occur in places with fewer, small-ranged mammalian frugivores, which may indicate dysfunctional seed dispersal. Nevertheless, our results also indicate that several wide-ranging bird species with high dispersal ability (large hand-wing index) that also occasionally feed on fruits may compensate for this potential dispersal loss. Our study sheds new light on dispersal anachronisms in Madagascar, and how defaunation and past species interactions may underlie current plant distributions.

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The ghost fruits of Madagascar: Identifying dysfunctional seed dispersal in Madagascar's endemic flora

Cited by 26 publications

References 45 publications

Influence of Late Holocene Climate Change and Human Land Use on Terrestrial and Aquatic Ecosystems in Southwest Madagascar

Influence of Late Holocene Climate Change and Human Land Use on Terrestrial and Aquatic Ecosystems in Southwest Madagascar

The kapok tree (Ceiba pentandra (L.) Gaertn, Malvaceae) as a food source for native vertebrate species during times of resource scarcity and its potential for reforestation in Madagascar

Megafrugivores as fading shadows of the past: extant frugivores and the abiotic environment as the most important determinants of the distribution of palms in Madagascar

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