Rainforests Of Southern South America Research Articles

A search for piroplasmids and spirochetes in threatened pudu (Pudu puda) and associated ticks from Southern Chile unveils a novel Babesia sp. and a variant of Borrelia chilensis.

Cervids are important hosts for ticks and although they are refractory to some tick-borne agents such as Borrelia, they do act as reservoirs for others such as Babesia. Babesia and Borrelia are commonly transmitted by Ixodes spp. associated with deer, and most of the knowledge on their biological cycles comes from northern latitudes of the globe. In this study, we performed genetic screenings to detect tick-borne agents in blood and Ixodes stilesi ticks collected from an insular population of threatened pudu (Pudu puda), a pygmy deer species that inhabits temperate rainforests of southern South America. Inferred by phylogenetic analyses for 18S rRNA, COI and cytb genes, our results unveiled a novel genospecies of Babesia (Babesia sp. pudui) genetically related to Babesia odocoilei, a species that infects Odocoileus virginianus deer in North America. Although blood of the deer was negative for Borrelia infection, multilocus sequencing typing performed in one I. stilesi tick revealed the occurrence of a novel genetic variant of Borrelia chilensis, differing 0.93% and 0.18% in flaB and pepX genes with the type of strain for the species, respectively. Such a genetic divergence could be the result of thousands of years of isolation because of recent glaciation events that separated pudus and their tick populations at Chiloé Island approximately 437,000years ago. The finding of a Babesia sp. has no precedents for wild and domestic ungulates in Chile and shows a novel piroplasmid that must be considered now on in rehabilitation centres and zoos that attend pudu deer. Further research is now necessary to confirm pathogenic roles.

A multi-scale assessment of habitat disturbance on forest animal abundance in South American temperate rainforests

Anthropogenic disturbance has dramatically degraded and reduced the extension of the temperate rainforests of southern South America, negatively affecting forest animals that depend on habitat attributes at local and landscape scales. We conducted a multi-scale assessment (from 1 to 4000 m) to understand better how local and landscape attributes influence forest animal abundance in an anthropogenic disturbance gradient. We selected five forest-dependent animal species to assess the effects of habitat alteration: an arboreal marsupial (Dromiciops gliroides) and four forest birds (Pteroptochos tarnii, Scytalopus magellanicus, Scelorchilus rubecula, and Sylviorthorhynchus desmursii). We recorded forest animal abundances in four different habitat types (old-growth native, secondary, and logged native forests and forestry plantations). We measured local attributes in the field and characterized landscape attributes remotely. We evaluated marsupial abundance using camera traps and forest bird abundance using point counts, which were analyzed with Generalized Linear Mixed Models. Locally, canopy cover positively predicted marsupial abundance, while the number of fallen logs positively predicted bird abundance. At the landscape scale, native forest cover positively affected marsupial abundance, with significant effects at all levels. Conversely, plantation cover negatively affected forest bird abundance, while landscape heterogeneity negatively affected both groups. Our results showed that the abundance of the forest animals assessed here depends on multi-scale determinants. At the local scale, we advise greater canopy cover and maintaining woody debris. On the landscape scale, maintaining native forest cover should prioritize biodiversity management in the southern South America temperate forests. It is also crucial to control the expansion of forest plantations and reduce forest fragmentation to guarantee the persistence of forest-dependent species.

Root suckering promotes recruitment in two temperate rainforest trees with contrasting shade tolerance

The regeneration niche differentiation helps to explain plant coexistence and thus biodiversity. The study of the regeneration niche has been traditionally based on sexual recruitment, while overlooking clonal growth. Root suckering offers a successful alternative for local dispersal under suboptimal conditions for sexual reproduction. For light-limited forests, we hypothesized that: 1) root suckering would increase the regeneration niche towards high-light conditions in shade-tolerant trees and towards dark conditions in light-demanding species; 2) contrasting responses of survival and growth to light availability would explain niche differentiation of both suckers and saplings; and 3) distinct responsiveness to light among species and recruit-types would reflect differences in functional traits. We tested these hypotheses with two evergreen tree species that coexist in the temperate rainforest of southern South America: Embothrium coccineum (light-demanding) and Eucryphia cordifolia (shade-tolerant). We measured the light availability in two study plots above each recruit and along transects established in the understory. Niche selection, niche differentiation and changes in survival probability with light were inferred from the analysis of the light frequency distributions. We evaluated the effect of light on the relative volumetric change in stems over a 1-year period. Functional traits of leaves, stems, and crowns were measured in suckers and saplings growing under similar light conditions; these traits were then compared among size classes, recruit-types and species. Root suckering was the prevalent reproduction mode of both studied species, extending the light niche towards open microenvironments only during the earliest ontogenetic stages. The poor structural strength of the leaves and wood of small Eucryphia saplings explains its underuse of open microsites. Neither photosynthetic assimilation nor carbon subsidy can sustain Embothrium suckers at the shadiest microsites. Suckering proved to increase the persistence of Embothrium until advanced stages of forest succession, facilitating its coexistence with the late-successional Eucryphia. Our study emphasizes that clonal growth is essential to understand the dynamics of temperate rainforests.

Regional-scale variation on Dromiciops gliroides occurrence, abundance, and activity patterns along a habitat disturbance gradient

AbstractHabitat structure may have a significant influence on the occurrence, abundance, and activity patterns of forest mammals. However, anthropogenic habitat disturbance changes habitat structure, which may alter those patterns of activity. We assessed occurrence, relative abundance, and activity patterns of Dromiciops gliroides, an arboreal marsupial endemic to the temperate rainforests of southern South America, contrasting four forest conditions at a regional scale: old-growth, second-growth, and logged forests, and abandoned exotic plantations. We conducted a camera-trap assessment in two consecutive austral summers across most of the Chilean range of D. gliroides, and compared habitat structure along a disturbance gradient. All structural features assessed differed among forest conditions. Dromiciops gliroides was present in all forest conditions, but its abundance decreased and activity got narrower as disturbance increased, being significantly lower in the exotic plantations. Activity patterns were variable among forest conditions and months, and were significantly more restricted temporally at exotic plantations. Although D. gliroides is tolerant to habitat disturbance, we show that structural alteration results in lower abundances and narrower activity patterns.

Pollination Patterns by Green-Backed Firecrown Hummingbirds

The Green-backed Firecrown is the only hummingbird species found throughout the temperate rainforests of southern South America and is among the region’s most important pollinators. A diverse assemblage of the region’s flora appears to rely on the Green-backed Firecrown for pollination, which makes the firecrown vital for ecosystem function. However, relatively little is known of firecrown ecology. We examined the foraging patterns of Green-backed Firecrowns of various ages and both sexes, using pollen samples taken from birds in southern Chile. We hypothesized that males and females would carry distinct pollen communities (sets of pollen morphospecies) and would differ in the number of pollen morphospecies carried. We found a clear difference between pollen communities carried by hummingbirds in summer and winter, but little differentiation by age and sex. We also found that females, on average, carried more pollen morphospecies than do males, and juveniles carried more morphospecies than do adults. All Green-backed Firecrowns carried significantly higher numbers of pollen grains in summer than in winter. Our results show intriguing differences in foraging behavior and pollination roles across ages and between sexes, which support anecdotal observations that adult males are territorialists while females and juveniles forage opportunistically. Since Green-backed Firecrowns are the only hummingbird species throughout most of their range, sexually divergent foraging patterns suggest that males and females may fill the ecological roles of different species. Our results add to the field’s understanding of the foraging patterns of Green-backed Firecrowns and help us better appreciate the complexity of its ecological role.

Physiological differences between root suckers and saplings enlarge the regeneration niche in Eucryphia cordifolia Cav.

Many clonal plants produce vegetative recruits that remain connected to the parent plant. Such connections permit resource sharing among ramets, explaining the high survival rates of vegetative recruits during establishment under suboptimal conditions for sexual regeneration. We propose that differences in the regeneration niches of sexual and vegetative recruits reflect different physiological adjustments caused by parental supply of resources to the ramets. We conducted ecophysiological measurements in saplings and root suckers of Eucryphia cordifolia Cav., a tree species of the temperate rainforest of southern South America. We compared the following traits of saplings and suckers: gas exchange at the leaf level, crown architecture, daily crown carbon balance, biomass allocation to above-ground tissues (leaf-to-stem mass ratio, leaf mass area and leaf area ratio), xylem anatomy traits (lumen vessel fraction, vessel density and size) and stem ring width. We also correlated the growth rates of saplings and suckers with relevant environmental data (light and climate). Saplings showed morphological, architectural and physiological traits that enhance daily crown carbon balance and increase water-use efficiency, in order to supply their growth demands while minimizing water loss per unit of carbon gained. The radial growth of saplings diminished under dry conditions, which suggests a strong stomatal sensitivity to water availability. Suckers have low stomatal conductance, likely because the carbon supplied by the parent plant diminishes the necessity of high rates of photosynthesis. The low responsiveness of sucker growth to temporal changes in water availability also supports the existence of parental supply. The physiological differences between sexual and vegetative recruits satisfactorily explain the ecological niche of E. cordifolia, with saplings restricted to more closed and humid sites.

Vindication of Ulota pygmaeothecia (Orthotrichaceae, Bryophyta)

Ulota pygmaeothecia (Müll.Hal.) Kindb. and Ulota luteola (Hook.f. & Wilson) Wijk & Margad. are two epiphytic mosses from the evergreen Magellanic rainforests of southern South America. Both mosses have been considered as distinct species since their original description, with their specific status retained following the comprehensive review by Nicolajs Malta of South American Ulota (1927). Recently the synonymization of U. pygmaeothecia and U. luteola was proposed (Wang & Jia 2016), based mainly on the similarities stated in the protologues and the study of the available type specimens of U. pygmaeothecia and U. fulvella, as the type materials of U. luteola were lost in the mail. In the present paper, all available type material for names associated with these two taxa, together with additional specimens recently collected, have been studied in depth. As a result, it has been found that both mosses show important sporophytic and gametophytic differences, both qualitative and quantitative, that allow for a precise distinction between them and they are reinstated here as distinct species. The morphological features that best differentiate U. luteola and U. pygmaeothecia are discussed and illustrated with light microscope and SEM pictures. Finally, an updated and detailed description of each species is presented.

Reduced Genetic Diversity and Increased Dispersal in Guigna (Leopardus guigna) in Chilean Fragmented Landscapes.

Landscape fragmentation is often a major cause of species extinction as it can affect a wide variety of ecological processes. The impact of fragmentation varies among species depending on many factors, including their life-history traits and dispersal abilities. Felids are one of the groups most threatened by fragmented landscapes because of their large home ranges, territorial behavior, and low population densities. Here, we model the impacts of habitat fragmentation on patterns of genetic diversity in the guigna (Leopardus guigna), a small felid that is closely associated with the heavily human-impacted temperate rainforests of southern South America. We assessed genetic variation in 1798 base pairs of mitochondrial DNA sequences, 15 microsatellite loci, and 2 sex chromosome genes and estimated genetic diversity, kinship, inbreeding, and dispersal in 38 individuals from landscapes with differing degrees of fragmentation on Chiloé Island in southern Chile. Increased fragmentation was associated with reduced genetic diversity, but not with increased kinship or inbreeding. However, in fragmented landscapes, there was a weaker negative correlation between pairwise kinship and geographic distance, suggesting increased dispersal distances. These results highlight the importance of biological corridors to maximize connectivity in fragmented landscapes and contribute to our understanding of the broader genetic consequences of habitat fragmentation, especially for forest-specialist carnivores.

Philodryas chamissonis (Reptilia: Squamata: Colubridae) preys on the arboreal marsupial Dromiciops gliroides (Mammalia: Microbiotheria: Microbiotheriidae)

Philodryas chamissonis, the Chilean long-tailed snake, is a diurnal predator mainly of Liolaemus lizards, but also of amphibians, birds, rodents and juvenile rabbits. Dromiciops gliroides (Colocolo opossum) is an arboreal marsupial endemic of temperate rainforest of southern South America. Little information is available about this marsupial's biology and ecology. Here we report the predation of one Colocolo opossum by an adult female P. chamissonis in a mixed Nothofagus forest, composed mainly by N. dombeyi, N. glauca and N. alpina trees, in the "Huemules de Niblinto" National Reserve, Nevados de Chillán, Chile. Since these two species have different activity and habitat use patterns, we discuss how this encounter may have occurred. Although it could just have been an opportunistic event, this finding provides insights into the different components of food chains in forest ecosystems of Chile.

Herbivory on temperate rainforest seedlings in sun and shade: resistance, tolerance and habitat distribution.

Differential herbivory and/or differential plant resistance or tolerance in sun and shade environments may influence plant distribution along the light gradient. Embothrium coccineum is one of the few light-demanding tree species in the temperate rainforest of southern South America, and seedlings are frequently attacked by insects and snails. Herbivory may contribute to the exclusion of E. coccineum from the shade if 1) herbivory pressure is greater in the shade, which in turn can result from shade plants being less resistant or from habitat preferences of herbivores, and/or 2) consequences of damage are more detrimental in the shade, i.e., shade plants are less tolerant. We tested this in a field study with naturally established seedlings in treefall gaps (sun) and forest understory (shade) in a temperate rainforest of southern Chile. Seedlings growing in the sun sustained nearly 40% more herbivore damage and displayed half of the specific leaf area than those growing in the shade. A palatability test showed that a generalist snail consumed ten times more leaf area when fed on shade leaves compared to sun leaves, i.e., plant resistance was greater in sun-grown seedlings. Herbivore abundance (total biomass) was two-fold greater in treefall gaps compared to the forest understory. Undamaged seedlings survived better and showed a slightly higher growth rate in the sun. Whereas simulated herbivory in the shade decreased seedling survival and growth by 34% and 19%, respectively, damaged and undamaged seedlings showed similar survival and growth in the sun. Leaf tissue lost to herbivores in the shade appears to be too expensive to replace under the limiting light conditions of forest understory. Following evaluations of herbivore abundance and plant resistance and tolerance in contrasting light environments, we have shown how herbivory on a light-demanding tree species may contribute to its exclusion from shade sites. Thus, in the shaded forest understory, where the seedlings of some tree species are close to their physiological tolerance limit, herbivory could play an important role in plant establishment.

Epiphytic Growth Habits of Chilean Gesneriaceae And the Evolution of Epiphytes Within the Tribe Coronanthereae1

Abstract Three monotypic and endemic genera of epiphytic Gesneriaceae (Gesnerioideae, Coronanthereae) occur in temperate rainforests of southern South America. In this article, intraspecific differences in rooted substrate and interspecific variation in epiphytic growth habits among these three Gesneriaceae species were assessed. The presence or absence of plants on the ground and main rooted substrate when growing epiphytically on trees were used to characterize epiphytic growth habits in two old-growth temperate rainforests of northern Chiloe Island (42°30′S) in Chile. An evolutionary interpretation based on reported phylogenies and morphologies within the Coronanthereae is proposed. Two species of Chilean Gesneriaceae, Mitraria coccinea Cav. and Asteranthera ovata (Cav.) Hanst., originate from the forest floor, then climb on trees while maintaining their main roots in the ground, and are classified as secondary hemiepiphytes. The third species, Sarmienta repens Ruiz & Pav., was found exclusively on tre...

First record on an amphibian in the canopy of temperate rainforests of southern South America: Eupsophus calcaratus (Cycloramphidae)

We record for the first time arboreal habits in amphibians from the temperate rainforests of southern South America. In April 2006 we collected an individual of Eupsophus calcaratus at 16 m height, in a large Eucryphia cordifolia tree of old-growth forest of Chiloe Island, southern Chile. This species was considered until now as a terrestrial species, and the similarities between forest ground and epiphytic layer may allow this species inhabit the canopy. However, the level of association among these frogs and the forest canopy is unknown. The canopy of southern South America forests remains barely known, and as other forest canopies, may support high species diversity.

SPATIAL VARIATION IN NEST-SITE SELECTION BY A SECONDARY CAVITY-NESTING BIRD IN A HUMAN-ALTERED LANDSCAPE

Abstract Characteristics of successful vs. unsuccessful nest sites are likely to vary over time and space in response to habitat changes. I used the Thorn-tailed Rayadito (Aphrastura spinicauda, Furnariidae), a cavity-nesting species endemic to the temperate rainforest of southern South America, as a model species to determine if territory use and nest-tree selection, and associated consequences for fitness, varied spatially in response to human-driven habitat changes. I established two 10 ha plots in each of three forest habitats that differed in structure and isolation: connected old-growth forest, connected logged forest, and isolated logged fragments. Characteristics of trees used for nesting varied among forest types, but nest success did not. In connected forests (old-growth and logged forest), snags were used more often than expected based on their availability. Nest survival models identified type of tree (snag vs. live tree) and epiphyte cover of trees as the variables with the strongest effects ...

Phylogenetic position of the monotypic Des Murs’ Wiretail (Sylviorthorhynchus desmursii, Aves: Furnariidae) based on mitochondrial and nuclear DNA

Parallelisms and paraphyletic assemblages are common among ovenbirds. Molecular markers are therefore the best approach when studying the evolutionary relationships among the members of this unparalleled diversified family. We obtained nucleotide sequence data from mitochondrial (cytochrome b) and nuclear genes (myoglobin and glyceraldehyde-3-phosphodehydrogenase) and used these to deduce the phylogenetic position of a monotypic genus endemic to the austral temperate rainforests of southern South America, the Des Murs’ Wiretail (Sylviorthorhynchusdesmursii Des Murs, 1847, Aves: Furnariidae). Phylogenetic analyses based on maximum parsimony, maximum likelihood and Bayesian inference all converged into a congruent topology, with a basal position of Des Murs’ Wiretail within Synallaxinae together with Tit–Spinetails (Leptasthenura). Our data reject the hypothesis of a phylogenetic relationship between Des Murs’ Wiretail and thistletails (Schizoeaca) which exhibit parallelisms in morphology, tail structure and nest architecture. Using a molecular clock based on the myoglobin intron 2 gene, we estimated a divergence time of Des Murs’ Wiretail from Tit-Spinetails of 14–15 Myr, which is associated with the appearance of sclerophyllous forest elements in Chile at the Middle–Upper Miocene.

Diversity and host tree preferences of vascular epiphytes and vines in a temperate rainforest in southern Chile

Vines and epiphytes contribute importantly to the biodiversity of temperate rainforests of southern South America. However, compared with their tropical counterparts, these functional groups have received less attention. We evaluated diversity, floristic composition and relative abundance of vascular epiphytes and vines within a humid temperate forest in northern Chiloé Island, southern Chile. We assessed whether epiphyte and vine species exhibit preferences among host tree species and tested whether species richness on tree hosts differs from that expected by chance, by comparing observed frequencies of occurrence (FO) and species richness with randomly simulated frequency distributions generated under the assumption of no epiphyte preferences. Finally, we tested for associations of epiphyte and vine species with host tree size (trunk diameter at breast height). Eleven species of ferns and nine angiosperms (seven vines, one epiphytic angiosperm and one shrub) were recorded growing epiphytically in a sample of 499 trees. The most abundant species were three vines, Luzuriaga polyphylla (Hook.) Macbr., Griselinia racemosa (Phil.) Taub. and Mitraria coccinea Cav., and five species of filmy ferns (Hymenophyllaceae). Most epiphytes and vines (65%) showed preference for one or two tree species, with seven species being overrepresented on Podocarpus nubigena Lindl. hosts and 10 underrepresented on Drimys winteri J.R. et G.Forster. Epiphyte and vine species richness was significantly lower than expected by chance on D. winteri and higher than expected on Nothofagus nitida (Phil.) Krasser. Three epiphytic ferns showed preferences for large-sized trees, while frequency of occurrence of three common vines was independent of host tree size.

High-Latitude Rainforests and Associated Eco-Systems of the West Coast of the Americas: Climate, Hydrology, Ecology, and Conservation.

Section 1. Climate, Hydrology, and History.- 1. North-South Variations in West Coast Hydrometeorological Parameters and Their Significance for Earth Systems.- 2. Factors Controlling the Climate of the West Coast of North America.- 3. Sulfur Cycling in Coastal Upwelling Systems and Its Potential Effects on Climate.- 4. Atmospheric and Geologic Constraints on the Biogeochemistry of North and South American Temperate Rainforests.- 5. Past Changes in Climate and Tree Growth in the Western Americas.- 6. Constraints on Terrestrial Primary Productivity in Temperate Forests Along the Pacific Coast of North and South America.- Section 2. Biotic Patterns.- 7. Biodiversity Patterns in Relation to Climate: The Coastal Temperate Rainforests of North America.- 8. Phytogeographic Relationships and Regional Richness Patterns of the Cool Temperate Rainforest Flora of Southern South America.- 9. A Comparative Review of Forest Dynamics and Disturbance in the Temperate Rainforests of North and South America.- 10 Patterns of Terrestrial Vertebrate Diversity in New World Temperate Rainforests.- 11. Avian Communities in Temperate Rainforests of North and South America.- 12. The Importance of Plant-Bird Mutualisms in the Temperate Rainforest of Southern South America.- 13. The Temperate Rainforest Lakes of Chile and Canada: Comparative Ecology and Sensitivity to Anthropocentric Change.- Section 3. Forest System Responses to Human Activities.- 14. Implications of Patch Dynamics for Forested Ecosystems in the Pacific Northwest.- 15. Assessing and Responding to the Effects of Climate Change on Forest Ecosystems.- 16. A Comparison of the Ecology and Conservation Management of Cool Temperate Rainforest in Tasmania and the Americas.- 17. Logging Effects on the Aquatic Ecosystem: A Case Study in the Carnation Creek Experimental Watershed on Canada's West Coast.- 18. Biodiversity of Canadian Forests, with Particular Reference to the West Coast Forests.- Section 4. Conclusion.- 19. Afterword.

Distribution and Abundance of Small Mammals along an Elevational Transect in Temperate Rainforests of Chile

Assemblages of small mammals in temperate Andean rainforests of southern South America are diverse but poorly known. Herein, we describe an elevational transect through temperate rainforests in Valle de La Picada, Chile, during February and March, 1984. The transect consisted of standardized removal trapping (165 traps set in lines at ca. 7-m intervals and operated for 6 consecutive days) at each of seven elevations: 425 m, 505 m, 620 m, 715 m, 820 m, 920 m, and 1,135 m. A total of 514 small mammals representing two species of marsupials and seven species of sigmodontine rodents was collected. Trap success averaged 7.4% across traps, days, and elevations. Number of captures by individual traps during the sample period was indistinguishable from a Poisson distribution, both throughout the transect and at individual levels, suggesting independence of captures among traps. Captures were biased significantly by trap type, with museum specials securing significantly more Dromiciops australis and all forms of Akodon than Sherman live traps; the same biases were suggested by captures of Irenomys tarsalis and Auliscomys micropus . As expected, total number of individuals taken at each elevation declined throughout the sampling period while the cumulative number of species rose. Number of species, number of individuals, and species diversity varied inversely with elevation. Number of species and species diversity taken each day reached a maximum after 2–4 days of sampling. Captures of Rhyncholestes raphanurus, Akodon sanborni , putative hybrids of A. sanborni and Akodon longipilis , and I. tarsalis were correlated inversely with elevation. Conversely, D. australis, A. longipilis , and A. micropus were taken more commonly at higher elevations, whereas captures of Oryzomys longicaudatus, Akodon olivaceus , and Geoxus valdivianus appeared unrelated to elevation. Systematic sampling procedures are viewed as essential for describing fundamental patterns of abundance and distribution that can be compared with other studies.