A comparison of Aguaje Palm fruit consumption by terrestrial mammals, focusing on the three main habitats in the Lago Preto Concession Area

List of Figures

Figure 1 Aguaje Palm (Mauritia flexuosa)……………………………………………

Figure 2 Aguaje Palm Fruit…………………………………………………………...

Figure 3 Spiny rat (Proechimys sp.)…………………………………………………

An Abstract of the Practical Research Project

BSc. Biodiversity & Conservation Management

Durrell Institute of Conservation and Ecology

University of Kent at Canterbury

2008
A comparison of Aguaje Palm fruit consumption by terrestrial mammals, focusing on the three main habitats in the Lago Preto Concession Area.

Vicki Johnson

The Aguaje Palm (Mauritia flexuosa) is a keystone species of the neo-tropical region. The palm provides a number of species for example tapir, spiny rat, agouti, paca and many more with an essential food resource during times of scarcity. The palms are utilised by the local people, and sold at the local markets. The palms are harvested for their fruit, for the production of ice cream and flavored drinks and for their trunks and leaves for construction purposes. However the palms are not harvested sustainably thus leading to the depletion in numbers. The fruit is collected by felling the palm, as it’s to dangerous for people to climb. Consequently the carrying capacity of the rainforest is reduced, and the whole ecosystem is effected.

Palms and frugivores form a mutualistic relationship within the neo-tropical ecosystem and form a basis on which other species can live. Rainforest ecosystems are so delicate, that any slight change within the flora and fauna can have devastating effects. The aim of this study was to identify which terrestrial mammals would be effected by the unsustainable harvest of the Aguaje palm.

To explore the objectives of this study fruit baited tracking stations were set up within each of the three habitats terra firma, varzea and aguajal. This was done by clearing a small section of ground and placing 5 aguaje fruits in the centre. The stations were checked each morning and the identity of the fruit consumer was recorded. The species that visited the stations the most were spiny rat, agouti, paca and armadillo, and varzea had the highest number of visitations.

The study concluded that the unsustainable harvesting of the aguaje fruit would have a detrimental impact on the whole ecosystem of the rain forest. The reduction in palms would lead to a reduction in frugivores and carnivores respectively. Therefore it is essential to manage the aguaje palm sensible.

One possible solution, is the use of agroforestry. This provides the local people with a valuable income, as well as the fruit can be harvested sustainably, meaning that it can sustain the ecosystem.

Introduction

The interaction between the production of fruits by angiosperms and their consumption by frugivorous vertebrates (Fleming 1987) has been evolving over a period of 70 million years (Estrada & Fleming 1986). This mutualistic relationship between plant and animal is most commonly found in the neo-tropics. Depending on habitat, 50-90% of shrub and tree species found in the neo-tropical regions, depend on frugivorous vertebrate species to disperse their seeds (Fleming 1987). Numerous species found in the neo-tropical regions are classified as frugivores by using Terborgh’s (Terborgh 1986) guidelines, stating that the definition of a frugivore is an animal whose diet consists of 50% or more of fleshy fruits (Terborgh 1986). Fruits are the primary food source for a number of neo-tropical taxa for instance Bats, Primates, Rodents Fish and Birds (Estrada & Fleming 1986; Galetti & Aleixo 1998). As well as frugivores, a number of carnivorous species complement their diets with fruit (Fleming 1987). The presence of a fruit bearing species has been nonexperimentally studied to show a positive correlation with the abundance of vertebrates (Moegenburg & Levey 2003).

Fig. 1 Mauritia flexuosa (Aguaje Palm) Fig. 2 Mauritia flexuosa (Aguaje Palm Fruit)

Pictures From Penn & Neise (2008)
swamps, as it competes with other flora species for access to the sunlight (Penn & Neise 2008). The Aguaje Palm can have up to 8 inflorescences per year, and bear up to 900 fruits each time (Delgado et al 2007). The fruit produced is an oval shaped drupe covered by cornea scales. The size can range from 5-7cm in length and 4-5cm in diameter (Delgado et al 2007).

The main mammals, which are partly dependent on the Aguaje Palm, are the Spiny rat (Prochimys sp.), Agouti (Dsayprocta fulignosa), Paca (Agouti paca), Lowland Tapir (Tapirus terrestris) and Collared Peccary (Tayassu tajacu) (Bodmer 1990; Brooks et al 1997). The co-dependence between species and the Aguaje Palm is present in the majority of the Peruvian Rainforest, as each depend on the other. The seeds of the palms can be dispersed in many ways. The Amazonian ungulates disperse the seeds over short distances by spitting out the seeds during mastication (Bodmer 1991). The Lowland Tapir is the only species that can pass the seed intact through its digestive tract, as other species can destroy the seeds with the rumen microbes (Bodmer 1991).

The Aguaje Palm is not only popular amongst the animals, but humans depend on the fruits for their livelihoods. Since timber extraction has become high on the agenda of governments, local people have had to find alternative livelihoods. Therefore the harvesting of the Aguaje palm has become a common non-timber forest product (NTFP). The Aguaje fruit is collected by the local people and sold at the markets in Iquitos, Peru. There is a high demand for the fruit as sacks are sold at the markets, which contain up to1000 fruits. On average 15 metric tonnes of Aguaje Fruit is brought into Iquitos daily for the production of soft drinks, ice cream and for the local use in the local fruit industry (Penn & Neise 2008 & Bodmer 1999). The palm is also utilised in other areas, for instance the leaves are used for the thatching of roofs, the trunk can be used for the house walls and the roots for medicinal purposes. However the palm is not collected sustainably. Unfortunately the harvesting of the fruit is not sustainable as to extract bunches of Aguaje fruit, the entire tree is felled. The trunk is hard and slippery making it difficult for people to climb, in order to extract the palm fruits. Therefore the felling of the tree is the only quick solution for the local people (Penn & Neise 2008). The understorey vegetation surrounding the Aguaje Palm tree can be disturbed significantly when harvesting the palm fruit (Galetti & Aleixo 1998). Therefore the removal of the Aguaje Palm can drastically effect the microhabitat within the area of the tree.

Aguaje and many other economically important plant species are being felled at a phenomenal rate in the Peruvian Amazon (Gentry and Vasquez 1989). The more the palms are harvested the greater the effect on the mammals which feed upon them. With every tree which is felled the carrying capacity of the rainforest is significantly reduced for the relevant species (Penn & Neise 2008). All species of Tapir are placed under pressure from habitat destruction, the Lowland Tapir in particular is threatened to local extinction in many areas of South America (Brooks et al 1997 & Bodmer 1997). The only way the extraction of palm trees can become economically and ecologically sustainable, is to strictly manage the harvesting (Galetti & Aleixo 1998).

Moreover the relationship between frugivore and Palm species is so closely linked that the reduction in one effects the other. For instance the reduction in seed dispersal species in the neo-tropical regions can be negatively correlated with the reduction in Palm species. Bush meat is one of the other common ‘non-timber forest product’ (NTFP) livelihoods amongst local communities in the Iquitos region. The meat provided from the bush meat species provides the local communities with a source of animal protein. Ungulates, Rodents and Primates make up the largest proportion of biomass being consumed (Robinson & Bodmer 1999). All species of Tapir have been placed under threat from habitat destruction and hunting pressure (Brooks 1997; Bodmer 1997). Tapirs are important for seed dispersal, therefore the reduction in numbers may lead to the reduction of palms within the habitat (Brooks 1997).

An idea that is accepted by a number of researchers, policy makers and conservationists is that regulation of a communities resembles a puzzle and that the removal of a single piece can cause the collapse of the entire community (Galetti & Alexixo 1998). This is relevant to the precious ecosystems that co-exist with one another. This is relevant to both the Tapir species and the Palm species as both play a critical role in the others existence.
Previous work by Petra Mikkolainen in the Pacaya-Samiria National Reserve and the Tamshiyacu-Tahuayo Community Reserve concluded that the Aguaje fruit was the only palm fruit of great importance to the terrestrial mammals. This was proved by using fruit baited tracking stations, which were baited with palm fruits from three different species Ungurahui (Jessenia bataua,) Huasai (Euterpe precatoria) and Aguaje (Mauritia flexuosa). The results proved that Ungurahui and Huasai fruit removal was considerably less than that of Aguaje (Mikkolainen 2004 Unpublished). Moreover the conclusions of the study highlighted the effect of fruit ripeness on the results. If the fruits were unripe than the fruit removal rates were reduced however if the fruits were ripe than the fruit removal by the terrestrial mammals was high (Mikkolainen 2004 Unpublished).

More studies need to be completed to determine the ecological relationship between palm and frugivorous species in order to determine the impacts of the Aguaje palm fruit harvesting on terrestrial mammals. Taking into consideration the results of Petra Mikkolainen, a project was designed in the Lago Preto conservation concessions to determine the effects of the palm fruit harvest on the terrestrial mammals. The aims were to identify which species feed upon the Aguaje palm fruit, in order to give a better understanding of the impacts of the unsustainable harvesting. Therefore the two hypotheses the project tests are as follows: