Ecological consistency across space: a synthesis of the ecological aspects of Dromiciops gliroides in Argentina and Chile

Abstract

Dromiciops gliroides is an arboreal marsupial found in the temperate forests of South America (36-43 °S). This species is the sole extant representative of the order Microbiotheria, and is a key seed disperser of many native plant species, including the keystone mistletoe Tristerix corymbosus. Here, we synthesized the current knowledge on the ecological aspects of this species, and compared the available information from Argentina and Chile. Population density (23 ± 2 (mean ± SE) individual/ha) and home range (1.6 ± 0.6 ha) appear to be relatively similar across a marked ecological gradient in the mainland, but lower densities (7 ± 2 individual/ha) and smaller home ranges (0.26 ± 0.04 ha) were detected at island sites. We detected regional variation in body condition in Chile, but there were no significant differences across a wider E-W gradient. Movement patterns fit a random walk model; such behavior might have important consequences in shaping plant's spatial patterns. Although our data suggest that D. gliroides is more tolerant to habitat disturbance than previously thought, its incapability to disperse across non-forested areas suggests that the rapid rate of habitat loss and fragmentation that characterizes southern temperate forests likely poses a serious threat to this species. These ecological similarities are surprising given that forests studied receive dramatically different rainfall and correspond to distinct forest types. The evidence synthetized here dispels some of the myths about this species but also stresses the need for more comprehensive ecological studies across its distribution range.

Frugivore-Mediated Selection in A Habitat Transformation Scenario

“…Avian dispersal in this mistletoe is apparently precluded by a fruit colour polymorphism at its southern range44. Although T. corymbosus completely depends on D. gliroides for dispersing its seeds, this marsupial has a broad diet including fleshy fruits of at least 16 species45, insects, and eggs46. In fact, D. gliroides cannot sustain a diet based only on fruits or insects47.…”

Persistence of Dromiciops gliroides in landscapes dominated by Pinus radiata plantations

“…Also, in the 1950's approximately a 45% of the landscape in the coastal range of South Central Chile was already transformed into agriculture [24,25], whereas the current proportion of "open" land uses in this region is approximately 21% [26]. This means that the present landscape might be more favorable to forest specialists such as D. gliroides, who might avoid moving through non forested habitats [10]. In any of the latter cases, management of pine plantations has the potential to influence a significant proportion of D. gliroides populations.…”

“…thickets, in which they build their nests [6][7][8]. Despite the latter, there is increasing evidence that D. gliroides can use environments such as secondary forests, shrublands and even sparse Eucalyptus plantations with a rich native understory [9,10]. Most of the studies on the ecology and biology of Monitos del monte have been conducted on populations in the evergreen forests of the Southern half of the species' range [e.g.…”

“…Most of the studies on the ecology and biology of Monitos del monte have been conducted on populations in the evergreen forests of the Southern half of the species' range [e.g. [1,[9][10][11][12][13][14][15]]. In contrast, the information available for D. gliroides living in deciduous forests is very scant and anecdotal (e.g.…”

New insights on the mistletoe Tristerix aphyllus (Loranthaceae): interaction with diurnal and nocturnal frugivorous species

“…Diurnal recordings indicate that T. aphyllus is almost exclusively dispersed by the mimid Mimus thenca (Mimidae, Molina 1782) in central Chile (Martínez del Río et al 1996, Medel 2000. This observation differs from an equivalent mistletoe-disperser system present in the temperate forests of southern South America (Argentina and Chile), which is composed by the hemiparasitic mistletoe Tristerix corymbosus and the relict marsupial Dromiciops gliroides (Amico & Aizen 2000, Fontúrbel et al 2012. As D. gliroides is not present at lower latitudes but replaced by the marsupial Thylamys elegans (Didelphidae, Waterhouse 1839), it is likely that this nocturnal species is involved in the seed dispersal process of the leafless mistletoe in central Chile.…”