Last updated: 12 Mar, 2015
A groundbreaking study featured in New Phytologist reveals the extraordinary “parental care” strategies of the coco de mer palm. This research highlights how Lodoicea maldivica ingeniously transforms its harsh Seychelles habitat to nurture its progeny, producing the plant kingdom’s largest fruits and shielding its offspring from competition.
Tourists often marvel at the coco de mer palm, or Lodoicea maldivica, primarily for its suggestive, uniquely shaped fruits. However, scientists are captivated by these colossal plants, abundant on the Seychelles islands of Praslin and Curieuse, for far more profound reasons.
The coco de mer exhibits a remarkable commitment to reproduction, generating copious amounts of pollen and gigantic fruits that, instead of dispersing, fall directly to the ground at the palm’s base. “This immense energy investment in such nutrient-depleted soil seems counterintuitive,” notes Dr. Christopher Kaiser-Bunbury from the Department of Biology at TU Darmstadt. This paradox spurred a collaborative study by researchers from the Swiss Federal Institute of Technology Zurich, the Seychelles Islands Foundation, and TU Darmstadt. “We questioned how these palms secure the necessary nutrients to sustain this process.”
The multi-year investigation into the slow-growing coco de mer palm within the UNESCO World Heritage Site Vallée de Mai on Praslin involved meticulous measurements. Scientists quantified phosphate and nitrogen investment in palm reproduction and growth, assessed nutrient availability in the soil, measured water flow down the trunk during rainfall, and monitored soil moisture around the plants.
The research team discovered that the coco de mer palm’s distinctive leaves play a crucial role in what can be described as “De Mer Taking Care Of Mom” equivalent in the plant world. These expansive, subtly feather-like leaves, reaching up to 10 square meters, are shaped like funnels, forming a conduit down the trunk. This ingenious design allows the palm to capture rainwater, along with organic debris from animals and plants. Even its own pollen, if uneaten by geckos, is recycled. Researchers found phosphate concentrations around coco de mer trunks to be three times higher than in surrounding palm species. Virtually all rainfall channeled by the dense leaf canopy converges at the palm’s base. Kaiser-Bunbury describes this system’s efficiency: “Even during heavy downpours, one can walk through the palm forest and remain remarkably dry.”
This natural “parental care” system ensures offspring, growing at the base of female palms, receive a rich supply of water and nutrients. “Areas under the leaf canopy and further from the trunk are notably drier and nutrient-poorer than expected,” Kaiser-Bunbury explains. The rainwater funneling mechanism effectively inhibits other plants from establishing themselves in these resource-scarce zones. “Many plants collect water, but none, to our knowledge, have refined it to such an extent,” the biologist states.
The coco de mer effectively engineers its own habitat, doing so with such success that it has cultivated a monodominant palm forest on Praslin. It reigned as the dominant species before human activities, including overharvesting and deforestation, nearly drove it to extinction. A diverse array of animals and plants have co-evolved with the coco de mer, continuing to coexist within the dense palm forest today.
This research is a collaborative effort with the Seychelles Islands Foundation, a non-governmental organization dedicated to protecting and managing Vallée de Mai. The study’s scope extends beyond merely understanding the palm’s unique characteristics.
Kaiser-Bunbury’s future research includes modeling coco de mer forest dynamics based on these novel findings. “We aim to understand how the palm’s monodominance can be sustained, even with active forest management, such as planting new palms,” the biologist explains. Historically, fruits were planted “in neat rows,” not in the naturally occurring clumps at the mother tree’s base. “We are keen to investigate the impact of this clumped growth pattern on the entire forest ecosystem, particularly on the associated endemic fauna,” Kaiser-Bunbury outlines as a key future research objective.
Based on a press release published by Technische Universität Darmstadt on 11 March 2015. For further information contact Kommunikation und Medien, S1|01 517, Karolinenplatz 5, 64289, Darmstadt, +49 6151 16-2063, presse@tu-darmstadt.de
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