Projects
ONGOING PROJECTS:
Monito del monte occurrence and mistletoe genetic diversity in contrasting habitats: predicting the outcome of ecological interactions
Abstract: Productive activities impact natural habitats all over the world to fulfill the needs of a growing population. Anthropogenic disturbance is capable to change habitat structure, altering species abundance, composition, and the interactions occurring among them. In spite of that, many native species are able to persist and thrive in disturbed habitats, in which the scarcity of key structural elements (e.g., natural cavities) could be compensated by an increased resource offer and landscape heterogeneity. However, the sole presence of a set of species in a disturbed habitat may be hiding other less obvious consequences such as the loss of genetic diversity. Such anthropogenic disturbance scenario could be particularly critical for plant-animal interactions, which play a major role in maintaining biodiversity. Among them, pollination and seed dispersal mutualisms play a major role on plant recruitment of >75% of the flowering plants. It is known that habitat disturbance is capable to disrupt those interactions, as a consequence of structural and microclimate changes that are able to alter interaction probabilities. Thus, altered recruitment processes could change plant community composition at the long term. Those responses are species- and ecosystem-specific, making difficult to generalize, and making extensive or long-term monitoring of those processes a challenging task. In the past two decades, the rapid development of molecular tools have changed the way we study patterns in the nature, by examining the processes instead. Multi-locus markers such as microsatellites allow researchers to examine the past history altogether with the present patterns, showing a more complete picture. Those molecular tools have been recently applied to the study of mutualist interactions, aiming to understand the underlying processes rather than the patterns, by providing hard evidence on gene flow, population structure, genetic diversity and ongoing demographic processes.
Most plants in temperate ecosystems rely on biotic vectors (mostly birds and mammals) for pollination and seed dispersal, which respond to strongly seasonal resources. In the temperate rainforests of southern South America we found a specialized mutualistic system composed by the keystone hemiparasitic mistletoe Tristerix corymbosus, which relies almost exclusively on the hummingbird Sephanoides sephaniodes for pollination, and on the relict arboreal marsupial Dromiciops gliroides for seed dispersal. The specialization of that system allows studying ecological interactions without the confounding effects of redundant species. Then, T. corymbosus populations are spatially structured by D. gliroides activity, and also they are highly genetically structured even in short (< 2 Km) distances, due to their particular reproductive system. Therefore, changes in habitat quality are expected to alter D. gliroides behavior, and then alter T. corymbosus spatial arrangement and genetic diversity. Large mistletoe clumps are typically found at disturbed habitats, which may be causing genetic diversity loss due to low gene flow across the landscape. Studying this phenomenon with traditional techniques as live trapping could be a huge endeavor, but mixing camera trap surveys with molecular markers may provide accurate estimations beyond any field assessment. Based on that, I hypothesize that: (1) mistletoe genetic diversity would increase with disperser’s occurrence, and (2) both D. gliroides occurrence and T. corymbosus genetic diversity would be higher at protected sites, compared to impacted sites, in response to habitat structure modification.
NEW! Camera-trap photo selection available here
Duration: 3 years (2016-2019).
Project location: Southern Chile (12 locations from Trongol Alto to Puerto Montt).
Involved staff: Francisco E. Fontúrbel (PI), Caren Vega (associate researcher), Rodrigo Medel (associate researcher).
Funding: FONDECYT grant # 11160152.
FINISHED PROJECTS:
Inter-individual network of spatial genetic variation in the hemiparasitic mistletoe Tristerix corymbosus: effects of plant neighborhood, pollination, and seed dispersal in a habitat transformation gradient
Abstract: Human activities are altering natural habitats at an unprecedented rate. Habitat loss and fragmentation affects on plant-animal interactions are well described in literature, as there is a strong theoretical framework developed about area and edge effects. However, effects of habitat transformation (i.e., the total or partial substitution of native vegetation with exotic species) are not that evident, and constitute a topic that has not been developed enough despite being a major biodiversity loss driver. Transformed habitats are usually structurally simpler and commonly dominated by generalist species that are capable to adapt to novel environmental conditions. In this human-altered habitat scenario, studying the response of ecological interaction, and particularly plant-animal mutualisms (pollination and seed dispersal) is imperative since the reproductive success of many plant species depend on them. Habitat structure and microclimate are acknowledged as determinant factors for plant and animals to interact, and its modification could seriously compromise the persistence of such interactions at disturbed habitats. Nevertheless, some plant-animal mutualisms are resilient to habitat disturbance due to its diffuse and asymmetric nature, in which specialist species interact with generalist species. Also, interacting species assemblages are likely to change in disturbed habitats, compromising plant’s ecological and evolutionary responses.
Over 75% of the native flora at the South American temperate rainforests is pollinated or dispersed by animal vectors. Among them, a particularly specialized case is the hemiparasitic mistletoe Tristerix corymbosus, which interacts with one pollinator (Sephanoides sephaniodes) and one disperser (Dromiciops gliroides) species. Despite its specialization, this mutualist system was found to persist in transformed habitats, contrasting to the interaction disruption patterns caused by habitat fragmentation. However, mistletoes thriving at transformed habitats were found to be densely aggregated in respect to native forest stands, which could be due to a neighborhood effect, since food resources (from early successional species) were more abundant at transformed habitats; moreover, diverse and rich plant neighborhoods are known to reduce dispersal distances.
Duration: 3 years (2014-2016).
Project location: Valdivian Coastal Reserve.
Involved staff: Francisco E. Fontúrbel (PI), Carezza Botto-Mahan (sponsor), Caren Vega (associate researcher), Rodrigo Medel (associate researcher).
Funding: FONDECYT post-doctoral grant # 3140528.
Tracking the monito del monte (Dromiciops gliroides) on native and transformed habitats: consequences for seed dispersal
Abstract: Dromiciops gliroides is an endemic marsupial of the Chilean rainforest, which has a major role as seed disperser. This species was considered to be restricted to native forests. However, we found this species inhabiting transformed habitats, composed by exotic Eucalyptus globulus trees and native understory. Dromiciops gliroides is the only disperser of the keystone mistletoe Tristerix corymbosus, which was densely aggregated at the transformed habitat. We intend to track Dromiciops gliroides at native and transformed habitats to determine whether habitat structural differences are changing disperser’s behaviour, which may also affect many other plant species that this marsupial disperse.
Duration: 1 year (2014).
Project location: Valdivian Coastal Reserve.
Involved staff: Francisco E. Fontúrbel (PI), Daniela Salazar (co-investigator, undergraduate dissertation), Alina B. Candia (education program collaborator), Carezza Botto-Mahan (advisor).
Students involved: Francisco Lucero, Javiera Malebrán.
Funding: Rufford Small Grants (grant 14669-2).
Results: One paper published in Integrative Zoology, one in Ecosphere and another one in Forest Ecology and Management. One poster presented (at the 2015 South America Rufford Conference), one talk given at the University of Chile, one talk at the SCB 2017 conference in Cartagena de Indias (Colombia), and one BSc. dissertation presented (by D.A. Salazar).
Quantitative assessment of the relationship between the parasitic mistletoe Tristerix aphyllus and its dispersers
Abstract: Tristerix aphyllus is a holoparasitic mistletoe of the arid and semi-arid regions of Chile. This mistletoe parasitizes only cacti species, being Echinopsis chiloensis and Eulychnia acida its most common hosts. This mistletoe flowers between March and August, and produces fruits between March and November, with a fruiting peak between July and September. The Chilean mockingbird (Mimus thenca) was described as the legitimate disperser of this mistletoe, but the role of other birds and small mammals –such as Thylamys elegans– remains unknown. We used camera traps to quantify T. aphyllus visitors during the peak of the fruiting seasons in order to determine its frugivorous assemblage and determine other potential seed disperser species.
See videos on YouTube: Mimus thenca, Diuca diuca, and Phyllotis darwini
Duration: 1 year (2013).
Project location: Reserva Nacional Las Chinchillas.
Involved staff: Carezza Botto-Mahan (PI), Francisco E. Fontúrbel (co-investigator), Rodrigo Medel (co-investigator).
Students involved: Francisco Lucero.
Funding: FONDECYT projects 11090086 and 3140528, Cleveland Metroparks Zoo - Cleveland Zoological Society (through the Scott Neotropical Fund program), the People's Trust for Endangered Species, Idea Wild, and Rufford Small Grants.
Results: One paper was published in Gayana Botanica.
Effects of habitat degradation on the monito del monte (Dromiciops gliroides Thomas) and its consequences on the seed dispersal interaction with an endemic mistletoe
Abstract: Dromiciops gliroides is an endemic marsupial of the Chilean temperate rainforest, and the only living Microbiotheriid. This species is an important seed disperser for many plants, but it is the sole disperser of the mistletoe Tristerix corymbosus, which provides food resources for other species, including pollinating birds. Anthropic habitat degradation is significantly transforming native habitats, but less attention has given to its consequences on natural populations and its ecological interactions. I propose to examine such consequences at three levels: on D. gliroides populations, on the magnitude of the seed dispersal interaction with T. corymbosus, and on the selective forces that the disperser exerts on the plant. This research is driven by three hypotheses: 1) D. gliroides abundances are lower at degraded forests, 2) D. gliroides removes less T. corymbosus fruits at degraded forests, and 3) Habitat degradation will change the significance and direction of the selection gradients on fruit traits.
Duration: 2 years (2011 to 2013).
Project location: Valdivian Coastal Reserve.
Involved staff: Francisco E. Fontúrbel (PI), Rodrigo Medel (advisor), Gabriel Castaño-Villa (associate).
Students involved: Alina Candia, Javiera Malebrán, Daniela Salazar.
Funding: The American Society of Mammalogists, Cleveland Metroparks Zoo - Cleveland Zoological Society (through the Scott Neotropical Fund program), the People's Trust for Endangered Species, Idea Wild, Rufford Small Grants and CONICYT.
Results: Four papers were published in Naturwissenschaften, the Journal of Mammalogy, the Journal of Ecology and Global Change Biology, one paper is currently under review and two aditional papers are almost ready for being sent to international journals. Two talks and one poster were presented in Chile, and one poster was presented in Brazil. We also gave workshops at rural elementary schools, and talks in Santiago.
A short video about the study site (borrowed from The Nature Conservancy YouTube channel):
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Indirect possitive effects of the hemiparasitic mistletoe Tristerix corymbosus on the reproductive success of Rhaphithamnus spinosus
Abstract:
Parasitic plants are assumed to cause deleterious effects on host plants. However, mistletoes usually have sugar-rich flowers and fruits and attract mutualists (pollinators and seed dispersers) for ensuring their reproductive success. We hypothesized that if phenological patterns between the parasitic and the host plant are coupled in time, the presence of the parasitic plant might benefit the host plant by the means of attracting mutualists. We tested this hypothesis in a particular study system at the Chilean temperate rainforests, where the keystone hemiparasitic mistletoe Tristerix corymbosus depends solely on the hummingbird Sephanoides sephaniodes for pollination and on the marsupial Dromiciops gliroides for seed dispersal. Despite the mistletoe relies completely on those two mutualists, they also interact with many other native plant species, including several T. corymbosus’ hosts. Among those hosts there is the black spine Rhaphithamnus spinosus, a quite common host that has tubular flowers and fleshy fruits, coinciding with the mistletoe’s pollination and seed dispersal syndromes. Considering that both species have a temporal overlap during flowering and fruiting, we aimed to test whether the presence of the mistletoe has an indirect positive effect for R. spinosus by attracting pollinators and seed dispersers that ultimately enhance its reproductive success.
Duration: 1 year (2012 to 2013).
Project location: Valdivian Coastal Reserve.
Involved staff: Alina Candia (PI, undergraduate dissertation), Francisco E. Fontúrbel (advisor), Rodrigo Medel (advisor).
Funding: This project was funded by grants of American Society of Mammalogists, Cleveland Metroparks Zoo - Cleveland Zoological Society (through the Scott Neotropical Fund program), the People's Trust for Endangered Species, Idea Wild, Rufford Small Grants conceded to F.E.F, and funding from the Universidad de Chile to R.M.
Results: One paper has been published in Oikos (PDF here), and two talks were given in Chile.
Rhaphithamnus spinosus flower during austral spring (photo: Erwin Ovando, september 2012).
The monito del monte (Dromiciops gliroides Thomas) in fragmented environments: a conservation model for the native forest
Abstract: Dromiciops gliroides is an endemic arboreal marsupial of the temperate Chilean forest, the only living representative of the Microbiotheria order. Although its population status remains unknown, it is currently classified as “Vulnerable” A1c by the IUCN. I propose to study the three–dimensional habitat use and movement patterns of D. gliroides in continuous and fragmented forest habitats to examine how its space use patterns are affected by habitat fragmentation. Results will be used to build a habitat use model, and to develop a model–species- based conservation strategy for the sustainable use of the forest. The research is driven by three working hypotheses: 1) D. gliroides shows a negative response to forest fragmentation, 2) D. gliroides uses a range of tree structures and the habitat in a three–dimensional way, and 3) D. gliroides shows a negative response to degraded forests and avoids the surrounding matrix of non–forested areas.
Duration: one year (2008).
Project location: Cascadas field site, Universidad de Los Lagos (41º07'05"S 72º36'50"W).
Involved staff: Francisco E. Fontúrbel (PI), Jaime E. Jiménez (advisor).
Funding: Wildlife lab at Universidad de Los Lagos, Idea Wild, Cleveland Metroparks Zoo - Cleveland Zoological Society (through the Scott Neotropical Fund program).
Results: Three papers published in edge-leading journal, four international talks given (USA, Argentina, Chile, and UK), and a conference for elementary school children.
Dromiciops gliroides movement paths at a 5-ha forest fragment.