Forests Of Southern South America Research Articles

Nutrients and drought alter tri‐trophic interactions in cool‐temperate forests

Abstract Herbivorous insects are the main consumers in forest ecosystems, and the complexity of trophic interactions varies with resource availability, heterogeneity among feeding guilds and the presence of natural enemies. In this study, we examined tri‐trophic interactions in Nothofagus pumilio (Fagales: Nothofagaceae) Poepp. & Endl. Krasser forests in southern South America. Specifically, we focused on the effect of nitrogen addition and a drought event on levels of insect herbivory by different feeding guilds and the rate of parasitism on leaf miners throughout the growing season (middle and late). Nitrogen (N) addition increased the foliar nitrogen content but had no effect on total damage by arboreal insects. However, the different feeding guilds responded differently to nitrogen addition, and these responses varied between average or dry year and within the growing season. Particularly, miner activity responded positively to nitrogen addition, increasing their incidence towards the late season of the average year. The positive effect of nitrogen addition on miner activity did not cascade up to the trophic level of parasitoids, which varied with the climatic context and the growing season. These results suggest that tri‐trophic interactions were mainly controlled by the climatic context, since consumers and their natural enemy responses were more dependent on the climatic context and growing seasons than on plant quality. Overall, we highlight the role of fluctuating abiotic resources and the heterogeneity within each trophic level in structuring tri‐trophic interactions in forest ecosystems.

Forest stand dynamics of a short‐stature tree species: Ecological knowledge for sustainable forest management

Abstract Worldwide, the implementation of forest management guidelines has tried to mimic natural forest dynamics. The Oliver forest stand dynamics model has been successful in bridging natural forest dynamics associated with the disturbances of various spatial scales and silviculture also related to various spatial scales of management. However, the application of this model (and others) is restricted to tall forests. We claim here that the general research and commercial interest bias towards tall tree species has permeated silviculture and forest management, and that both the stand dynamics of short‐stature tree species and their treatment have remained largely unexplored and unknown. Using one short‐stature tree species, Nothofagus antarctica, as a model system, we show that this species indeed follows a stand dynamic different from other tall Nothofagus‐dominated forests in southern South America. This species forms short, mature, even‐aged stands without large canopy gaps that promote tree regeneration. With this in mind, we propose a conceptual ecology‐based silvicultural guideline focusing on the creation of strip cuts or gaps along with topsoil scarification to ensure regeneration and forest reorganization after disturbances. Policy implications. The acknowledgement that short‐stature tree species follow a stand dynamic different from tall tree species necessarily implies that they must be managed differently. This recognition, along with the implementation of ecology‐based silvicultural recommendations, represents strong arguments to make modifications to forest legislation that, together, must be aimed at conservation and sustainable forest management.

Does predation drive Chilean Elaenia (Elaenia chilensis) nest-site selection in the temperate forest of southern South America?

Does predation drive Chilean Elaenia (Elaenia chilensis) nest-site selection in the temperate forest of southern South America?

Does competition management improve the ecophysiological response to water shortage of mixed woodland species of North Patagonia?

Globally, the increasing forests vulnerability and drought-induced forest mortality events, extended to a larger scale, may have the potential to rapidly alter forest functioning and the provision of ecosystem services. Patagonian forests in Southern South America constitute an extensive reservoir of wildlife, but at the same time they have high productive potential. These low-mixed forests are composed of co-dominant species that are highly disturbed by local population, both for cattle raising and wood extraction; and different efforts are being dedicated to improve their management. Very little is known about the response of their different woody species to climatic variation, particularly to severe drought in particular, that may guide management strategies to improve productivity and resilience in context of drought stress and climate change. The present study aimed at characterizing the physiological strategies of response to drought to identify the most vulnerable and most resilient species to drought and how they respond under different competition levels. The response of four species of the Andean Patagonian low mixed forest was quantified at three moments of the 2018–2019 growing season in three sites through measurements of the net carbon exchange, vulnerability to xylem cavitation, tissue water relations, and damage of the photosynthetic apparatus. Additionally, records of average monthly values of precipitation and air temperature were used to calculate a standardized precipitation-evapotranspiration index. The normal climatic conditions of NW Patagonia region are characterized by water deficits during the spring-summer growing season, but the studied season presented lower values of standardized precipitation-evapotranspiration index respect to the historical mean values, indicating drier than normal conditions. Analysis of the tissue water relations showed that, in all cases, competition had no effect over the different studied parameters. There were species-specific differences in the models fitted to the vulnerability to cavitation curves; as a whole, all the species differed from each other. Overall, for all the physiological response traits studied, the Site, Species, and Season factors were important predictors in the minimum adequate model. Although there is an effect of competition on the individual annual growth, that effect is not evidenced in physiological variables of punctual measurement. Our results suggest that the effect of summer drought cannot be modulated by density management. The productivity of the species of interest can be improved, but not their adaptability, at least to severe events such as the one of the year of study.

Tree-cavity survival for biodiversity in temperate forests of South America: A multi-scale approach

Tree cavities are critical habitat attributes for a diversity of species that use them for reproduction and shelter. Worldwide, their availability has shown an intense decline in forests because of the loss of old-growth stands and the reduction in cavity recruitment. These disturbance processes are influenced by factors occurring across different scales: from cavities to landscapes. We analyzed the survival of 613 cavities in 455 trees in old-growth and second-growth forests over 10 years in Andean temperate forests in southern South America, Chile. Kaplan–Meier and Cox proportional hazards models were used to determine median cavity survival and its influencing factors at the cavity, tree, stand and landscape scales. The median survival was six years. Non-excavated cavities (6 years) survived longer than excavated cavities (4 years), with a significantly longer lifespan in large decaying trees. Cavities’ survival was strongly influenced by cavity- and tree-scale factors, including their origin, the vertical cavity depth, tree decay class, tree branch order and tree diameter class. In old-growth forests, most cavities were found in live decaying trees, while in second-growth forests they were mostly in long-dead trees (snags). We suggest that management should maintain forest structural complexity, retaining dead wood and trees in different stages of decay to permit a continuous supply of substrates over time for the formation of cavities.

Communal nesting is the optimal strategy for heat conservation in a social marsupial: lessons from biophysical models.

Endothermy, understood as the maintenance of continuous and high body temperatures owing to the combination of metabolic heat production and an insulative cover, is severely challenged in small endotherms inhabiting cold environments. As a response, social clustering combined with nest use (=communal nesting) is a common strategy for heat conservation. To quantify the actual amount of energy that is saved by this strategy, we studied the social marsupial Dromiciops gliroides (monito del monte), an endemic species of the cold forests of southern South America. It is hypothesized that sociability in this marsupial was driven by cold conditions, but evidence supporting this hypothesis is unclear. Here, we used taxidermic models ('mannequins') to experimentally test the energetic benefits of clustering combined with nest use. To do this, we fitted and compared cooling curves of solitary and grouped mannequins, within and outside of a nest, at the typical winter ambient temperatures of their habitat (5°C). We found that the strategy that minimized euthermic cost of maintenance was the combination of nest use and clustering, thus supporting communal nesting as a social adaptation to cope with the cold. Considering the basal metabolic rate of monitos, our estimates suggest that the savings represents almost half of energy consumption per day (in resting conditions). This study shows how simple biophysical models could help to evaluate bioenergetic hypotheses for social behavior in cold-adapted endotherms.

Three new genera of large marsh beetles (Coleoptera: Scirtidae) from Valdivian temperate rain forests of southern South America.

The present paper fills a gap in the knowledge of the largest marsh beetles in the Neotropics. Argelodes gen. nov., Solierodes gen. nov. and Mucronotus gen. nov. are described from Southern South America. Argelodes and Solierodes are monotypic, contain Argelodes magnificus sp. nov. and Solierodes rousseli (Solier, 1849) comb. nov., while Mucronotus contains five species: Mucronotus velutinus (Solier, 1849) comb. nov., M. schwabei (Pic, 1938) comb. nov., and three newly described onesM. enigmaticus sp. nov., M. patagonicus sp. nov., and M. valdivianus sp. nov. Affinities of newly described genera with Australian taxa are briefly discussed. Pronotal modifications in marsh beetles are illustrated and discussed.

Purification and Identification of Novel Antioxidant Peptides Isolated from Geoffroea decorticans Seeds with Anticoagulant Activity.

Geoffroea decorticans is a xerophilous deciduous tree present in most arid forests of southern South America, which is commonly used in traditional medicine. The seeds of this tree have been previously investigated for their singular chemical composition, but their protein content has been poorly investigated. Herein, we report the isolation, purification, and characterization of a set of thermostable peptides derived from Geoffroea decorticans seeds (GdAPs) with strong antioxidant and anticoagulant activities. The most potent antioxidant peptides showed a half maximal inhibitory concentration (IC50) of 35.5 ± 0.3 µg/mL determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH). They also caused a dose-dependent prolongation of the aPTT clotting time with an IC50 value of ~82 µg/mL. Interestingly, MALDI-TOF/MS analysis showed the presence of three major peptides with low molecular weights of 2257.199 Da, 2717.165 Da, and 5422.002 Da. The derived amino-acid sequence of GdAPs revealed their unique structural features, exhibiting homology with various proteins present in the genome of Arachis hypogaea. All in all, our data suggest a direct applicability of GdAPs for pharmaceutical purposes.

The presence of kelp Lessonia trabeculata drives isotopic niche segregation of redspotted catshark Schroederichthys chilensis

Kelp forests are associated with high biodiversity as they provide habitat and food source for many species. Redspotted catshark Schroederichthys chilensis is a coastal shark species associated with kelp forests of southern South America dominated by Lessonia trabeculata. Despite its common occurrence redspotted catshark the knowledge on its trophic ecology is rudimentary. This study aimed to assess the effects of presence/absence of kelp L. trabeculata on the isotopic niche of redspotted catshark through comparison of δ13C and δ15N in its blood and fin tissues (non-lethal samples). We found that males were characterized by higher trophic position and enriched carbon sources compared to females in locations where kelp was present. In contrast, males and females were characterized by similar isotopic niche in absence of kelp. These differences are most probably an effect of higher prey diversity associated with microhabitats generated by kelp forests that allow sexual segregation of isotopic niche. Therefore, extensive kelp harvest may cause significant effects in isotopic niche and nutritional status of adult redspotted catshark and may negatively affect its populations.

Biotic and abiotic drivers of carbon, nitrogen and phosphorus stocks in a temperate rainforest

Forest ecosystems are recognized for their large capacity to store carbon (C) in their aboveground and belowground biomass and soil pools. While the distribution of C among ecosystem pools has been extensively studied, less is known about nitrogen (N) and phosphorus (P) pools and how these stocks relate to each other. There is also a need to understand how biotic and abiotic ecosystem properties drive the magnitude and distribution of C-N-P stocks. We studied a temperate rainforest in southern South America to answer the following questions: 1) how are C-N-P total stocks distributed among the different ecosystem pools?, 2) how do C:N, C:P and N:P ratios vary among ecosystem pools?, and 3) which are the main biotic and abiotic drivers of C-N-P stocks? We established 33 circular plots to estimate C, N, and P stocks in different pools (i.e. trees, epiphytes, understory, necromass, leaf litter, and soil) and a set of biotic (e.g., tree density and richness) and abiotic variables (e.g., air temperature, humidity and soil depth). We used structural equation modeling to identify the relative importance of environmental drivers on C-N-P stocks. We found that total ecosystem stocks (mean ± SE) were 1062 ± 58 Mg C ha−1, 28.8 ± 1.5 Mg N ha−1, and 347 ± 12.5 kg P ha−1. The soil was the largest ecosystem pool, containing 68%, 92%, and 73% of the total C, N, and P stocks, respectively. Compared to representative temperate forests, the soil of this forest contains the largest concentrations and stocks of C and N. The low P stock and wide soil C:P and N:P ratios suggest that P may be limiting forest productivity. The ecosystem C-N-P stocks were mainly driven by abiotic properties measured in the study area, however for N stocks, variables such as plant diversity and canopy openness were also relevant. Our results provide evidence about the importance not only of understanding the differences in C, N, and P stocks but also of the factors that drive such differences. This is key to inform conservation policies related to preserving old-growth forests in southern South America, which indeed are facing a rapid land-use change process.

Climate response and drought resilience of Nothofagus obliqua secondary forests across a latitudinal gradient in south-central Chile

The climate response and resilience of tree growth to drought events have been widely reported for forests from the Northern Hemisphere. However, studies are much scarcer in the extra-tropical forests of southern South America. Mediterranean and Temperate forests of Chile are suffering from a moderate warming and a sustained precipitation decrease, occurring on top of an unprecedented megadrought since 2010. This study evaluated tree-growth patterns, the climate response and drought resilience of nine secondary Nothofagus obliqua forests across a latitudinal gradient from Mediterranean to Temperate climate in the Andes of Chile (35.7° to 40.3° S). Moreover, to improve the understanding of the spatial variation in productivity patterns, this research assessed trends in the maximum Normalized Difference Vegetation Index (peak in the NDVI) across the gradient for 2001–2018. Tree-growth patterns were highly influenced by stand dynamics, with steep decreasing trends in most of the stands related to a gradual canopy closure. Productivity trends had a flat pattern north of 38oS, but positive trends south of this latitude, which were mostly attributed to stand development. Tree growth was positively related to precipitation in all the sites, with annual and summer rainfall being more important in the north (Mediterranean climate) and south (Temperate climate), respectively. Conversely, maximum temperature had a negative effect on growth in most of the studied forests. This implies that projected warmer and drier conditions may have a detrimental effect on N. obliqua growth during coming decades. The two northern stands, located at the species dry range edge, were among the most resilient to drought and have not been strongly affected by the current megadrought in the area. Overall climate conditions, however, do not define the tolerance of stands to droughts, likely because local environmental and forests conditions play a key role. Although droughts have not strongly impacted the growth of N. obliqua across its distribution so far, future studies should assess the effects of the current long-term megadrought on growth resilience, and physiological studies should address the impacts of droughts and heat waves on forest function beyond what growth can unveil.

Long-lasting effects of unplanned logging on the seed rain of mixed conifer-hardwood forests in southern South America

Understanding the effects of disturbance on seed rain is critical to predict changes in forest species composition and diversity. Logging effects on seed rain in a mixed conifer-hardwood forest complex in southern Brazil were evaluated. One year of seed rain data were collected from a large-scale observational experiment in logged and protected forests and quantity and average seed size weighted by species abundance (CWM) were compared between old-growth and logged stands 55 years after logging activities. Using these data, variations in frequency of functional groups of species in the seed rain were examined to see if they could be attributed to logging. Results show that the number of seeds per trap was highly right-skewed, ranging from 13 to 12,788 seeds per trap in one year. Seed rain was affected by logging history, with seed traps in old-growth plots receiving significantly less seeds than traps in logged plots. All species included mean seed size weighted by species abundance were significantly smaller in logged than in old-growth forests. This difference persisted after the exclusion of Araucaria angustifolia, a large-seeded pioneer which was intensively logged, although the difference of seed size between the two forest classes was greatly reduced. Species abundance in the seed rain differed significantly from the established tree community, between logged and old-growth stands. The composition of the seed rain was much more variable than the composition of the established tree community and its points more scattered over the ordination space than the points corresponding to the protected forests. The number of collected seeds across different functional groups of species significantly differed between logged and old-growth plots. The seed rain of logged forests reflects their arrested succession as indicated by reduced abundance of functional groups such as pioneers, large seeded pioneers and Araucaria, as well as reduced functional diversity. Seed rain differences between logged and old- growth stands reflect the intensive logging of A. angustifolia.

Kelp forests at the end of the earth: 45 years later.

The kelp forests of southern South America are some of the least disturbed on the planet. The remoteness of this region has, until recently, spared it from many of the direct anthropogenic stressors that have negatively affected these ecosystems elsewhere. Re-surveys of 11 locations at the easternmost extent of Tierra del Fuego originally conducted in 1973 showed no significant differences in the densities of adult and juvenile Macrocystis pyrifera kelp or kelp holdfast diameter between the two survey periods. Additionally, sea urchin assemblage structure at the same sites were not significantly different between the two time periods, with the dominant species Loxechinus albus accounting for 66.3% of total sea urchin abundance in 2018 and 61.1% in 1973. Time series of Landsat imagery of the region from 1998 to 2018 showed no long-term trends in kelp canopy over the past 20 years. However, ~ 4-year oscillations in canopy fraction were observed and were strongly and negatively correlated with the NOAA Multivariate ENSO index and sea surface temperature. More extensive surveying in 2018 showed significant differences in benthic community structure between exposed and sheltered locations. Fish species endemic to the Magellanic Province accounted for 73% of all nearshore species observed and from 98–100% of the numerical abundance enumerated at sites. Fish assemblage structure varied significantly among locations and wave exposures. The recent creation of the Yaganes Marine Park is an important step in protecting this unique and biologically rich region; however, the nearshore waters of the region are currently not included in this protection. There is a general lack of information on changes in kelp forests over long time periods, making a global assessment difficult. A complete picture of how these ecosystems are responding to human pressures must also include remote locations and locations with little to no impact.

Efecto de la diversidad funcional sobre la tasa de evapotranspiración: un análisis anual de tres bosques templados chilenos

There is a link between the diversity of forest ecosystems and the evapotranspiration (ET) ecosystem process. However, there is little knowledge of this link in temperate forests of southern South America. Given the influence of ET in relevant ecosystem services, such as hydrological or climatic regulation, it is important to understand the effect of the change in species composition on this process. The objective of this research was to determine the relationship between functional diversity and the seasonal variation of ET using three native forest ecosystems that differ in structure, composition of dominant species and proportion of phenological strategies as a study model. The general pattern shows that there is a significant negative relationship between the community weighted average of the specific leaf area attribute; CWM-SLA and the ET process. We found seasonal changes in ET in the three ecosystems, which was greater in spring-summer. There is a positive relationship between the percentage of evergreen species in the canopy and total annual ET of each ecosystem. This would explain the negative relationship between CWM-SLA and ET, since the ecosystem with the highest proportion of evergreen species corresponds to the one with the lowest CWM-SLA. The results of this study contribute to giving relevance to the functional diversity of native forest ecosystems over a crucial ecosystem process for the provision of various ecosystem services. Subsequent studies could assess the effect of the loss of functional diversity on ecosystem processes in order to relieve the need to conserve and/or restore the native forest from this perspective.

Revision of Tropopterus Solier: A disjunct South American component of the Australo-Pacific Moriomorphini (Coleoptera, Carabidae)

TropopterusSolier, 1849, precinctive to southern South America, is taxonomically revised. Six new species are described:T. peckorumsp. nov.,T. robustussp. nov.,T. canaliculussp. nov.,T. trisinuatussp. nov.,T. minimucrosp. nov., andT. fieldianussp. nov.Merizodus catapileanusJeannel, 1962, is synonymized withT. montagneiSolier, 1849. Lectotypes are designated forT. montagnei,T. giraudyiSolier,T. duponcheliiSolier, andT. nitidusSolier (=T. duponchelii).Tropopterus peruvianusStraneo is noted as anomen dubium, with its identity and taxonomic placement to be substantiated via neotype designation. Phylogenetic relationships amongTropopterusspp. are hypothesized based on 37 morphological characters, the distributions of which are analyzed under the parsimony criterion, with the cladogram root established betweenTropopterusand its adelphotaxon from New South Wales, Australia. Speciation in the group has occurred predominantly at a limited geographical scale relative to the overall generic distribution, with three pairs of sister species sympatric. However phylogenetic divergence between taxa in the more northern, sclerophyllous forest characterized byNothofagus obliqua(Brisseau de Mirbel) and those occupying the Valdivian and North Patagonian Rain Forest dominated byN. dombeyi(Brisseau de Mirbel) is observed in two instances of phylogenetic history. Using specific collecting locality records, it is shown thatTropopterusbeetles have been collected syntopically and synchronically with species ofGlypholomaJeannel (Coleoptera, Staphylinidae),AnaballetusNewton, Švec & Fikáček (Coleoptera, Leiodidae),AndotypusSpangler (Coleoptera, Hydrophilidae), andNovonothrusBalogh (Acari, Oribatida). These concordant ecological occurrences document a cohesiveNothofagusforest leaf-litter community. These genera plus other Valdivian Rain Forest invertebrate taxa all exhibit an Austral disjunct biogeographical pattern that corroborates trans-Antarctic vicariance between theNothofagusforests of southern South America and Australia. Male genitalic antisymmetry is shown to be a synapomorphy ofTropopterus, though the female reproductive tract retains the plesiomorphic orientation observed in all other moriomorphine taxa.

Taxonomy, systematics and geographic distribution of ground frogs (Alsodidae, Eupsophus): a comprehensive synthesis of the last six decades of research.

The genus Eupsophus (ground frogs) inhabits exclusively the temperate forests of southern South America (Chile and Argentina). The current delimitation of the genus was reached in the late 1970s, when only two species were recognized, but since then the number of described species steadily increased, reaching a maximum of 11 by 2012. Subsequent studies that applied explicit species delimitation approaches decreased the number of species to six in 2017 and raised it again to 11 the following year, including an undescribed putative species. Despite these taxonomic changes, the two species groups traditionally recognized, roseus and vertebralis, have been maintained. Another recent contribution to the taxonomy of the genus was the explicit recognition of the extremely high level of external phenotypic variation exhibited by species of the roseus group, which undermines the utility of some diagnostic characters. Here we provide a critical review of the extensive taxonomic and systematic literature on the genus over the last six decades, to examine the evidence behind the recurrent taxonomic changes and advances in its systematics. We also update and complete a 2017 review of geographic information, provide additional qualitative observations of external characters commonly used in the diagnoses of species of the roseus group, and reassess the phylogenetic position of a putative new species from Tolhuaca (Chile), which was not included in the last species delimitation study. The present review shows that: 1) there is no congruence between the patterns of phenotypic and genetic/phylogenetic differentiation among species of both groups; 2) in the roseus group, the intraspecific variation in some external characters is as high as the differences described among species; 3) there is little morphological and bioacoustic differentiation within species groups, and inconsistencies in the chromosomal evidence at the genus level; 4) under the latest taxonomic proposal (2018), species of the roseus group still lack consistent and reliable diagnoses and their distribution limits are poorly defined; and 5) the population from Tolhuaca represents an additional undescribed species under the most recent taxonomic framework. Finally, we discuss the implications of these findings for the taxonomy and biogeography of the genus, pointing out some areas that require further research to understand their patterns and processes of diversification.

Are small abandoned plantations a threat for protected areas in Andean forests? The potential invasion of non-native cultivated species

Abandoned farms with small fruit plantations of the non-native species Prunus cerasus and Malus domestica are common in protected areas of the temperate forests of southern South America (TFSA), in Patagonia. Our aims were to determine whether an invasion of P. cerasus and M. domestica might be starting in protected areas, and whether either native or alien animal species are involved in the dispersal process. We evaluated sapling and seed spread, adult tree distribution in three habitats, and seed dispersal vectors of P. cerasus and M. domestica in “Los Alerces” National Park (Argentina). We sampled mature trees, saplings and seeds of P. cerasus and M. domesticain in two plots located next to plantations. Adult trees and mammal faeces also were searched for on roads, hiking trails, deforested areas, plots and transects opened by us. We monitored fruiting trees with cameras and we caught birds to obtain faeces. Saplings of P. cerasus were abundant and their locations were not related to adult locations, but saplings of M. domestica were rare. Ninety-two percent of P. cerasus adult trees were found in successional forest, whereas 99% of M. domestica trees were in deforested areas. Faeces of native foxes contained high number of intact seeds of both plant species studied, but we did not find any in the bird faeces. Our results indicates that P. cerasus has been invading natural habitats in protected areas of TFSA, and that foxes can be the major dispersal vectors. Further, successional forest is the most invasible habitat.

Geographical variation in the evolutionary diversity of tree communities across southern South America

AbstractAimTo determine the principal drivers of variation in the evolutionary diversity of forest tree communities, with a focus on the temperate forests of South America.LocationForests across southern South America, extending from tropical forests in southern Brazil, to the temperate forests of southern Chile and Argentina.MethodsWe compiled a database of 742 forest tree community inventories spread over six countries and 12 biomes, or major vegetation types. In total, these inventories covered 3075 species of shrubs and trees. We combined this dataset with a temporally calibrated phylogeny that included all species. For each community, we evaluated multiple measures of evolutionary diversity, including phylogenetic diversity sensu stricto (PD), which is the sum of the branch lengths of a phylogeny that includes all species in a community, and its equivalent standardized for variation in species richness (ses.PD), which we refer to as lineage diversity.ResultsWe found that biome affiliation is the most important determinant of the evolutionary diversity of woody plant communities, with climate also showing a significant influence. Communities in wet evergreen tropical forest have the highest species richness and the highest PD, but the lowest lineage diversity, while temperate forests in southern South America show the lowest species richness and PD, but the highest lineage diversity.Main conclusionsOur results contradict the idea that temperate floras represent recently derived, evolutionarily poor subsets of tropical floras. Rather, the high lineage diversity we find in the temperate forest communities supports the ‘austral conservatism hypothesis’, which states that the flora of southern South america has evolved independently from the Neotropical Domain over tens of millions of years. Our identification of the evolutionary distinctness and richness of this flora suggests that it deserves as much conservation attention as the more species‐rich tropical forests of South America and that southern South American forests should not be lumped into the Neotropical Floristic Province.

The effect of spatial context and plant characteristics on fruit removal

Attracting frugivores for fruit removal is a crucial step in the reproductive success of those plants that depend on animals for seed dispersal. This mutualism involves many plant extrinsic and intrinsic factors that affect fruit removal. Along the northern portion of the temperate forest of southern South America, the nocturnal marsupial Dromiciops gliroides is the only effective disperser of the mistletoe Tristerix corymbosus. This system, where a single disperser removes the fruits of a plant is simple compared to systems that include multiple dispersers and represents a unique opportunity to study the effect of extrinsic and intrinsic factors in frugivore plant choices for fruit removal. With a hierarchical model, we evaluated the effects of spatial context (accessibility and tree cover) and plant characteristics (age and crop size) in fruit removal during four fruiting seasons. While all these variables affected fruit removal, only accessibility and plant age had consistent and positive effects across years. After studying four fruiting seasons, we found that characteristics associated with frugivores’ habits are the most important factors for the reproductive success of plants dispersed by animals.

The Oldest, Slowest Rainforests in the World? Massive Biomass and Slow Carbon Dynamics of Fitzroya cupressoides Temperate Forests in Southern Chile.

Old-growth temperate rainforests are, per unit area, the largest and most long-lived stores of carbon in the terrestrial biosphere, but their carbon dynamics have rarely been described. The endangered Fitzroya cupressoides forests of southern South America include stands that are probably the oldest dense forest stands in the world, with long-lived trees and high standing biomass. We assess and compare aboveground biomass, and provide the first estimates of net primary productivity (NPP), carbon allocation and mean wood residence time in medium-age stands in the Alerce Costero National Park (AC) in the Coastal Range and in old-growth forests in the Alerce Andino National Park (AA) in the Andean Cordillera. Aboveground live biomass was 113–114 Mg C ha-1 and 448–517 Mg C ha-1 in AC and AA, respectively. Aboveground productivity was 3.35–3.36 Mg C ha-1 year-1 in AC and 2.22–2.54 Mg C ha-1 year-1 in AA, values generally lower than others reported for temperate wet forests worldwide, mainly due to the low woody growth of Fitzroya. NPP was 4.21–4.24 and 3.78–4.10 Mg C ha-1 year-1 in AC and AA, respectively. Estimated mean wood residence time was a minimum of 539–640 years for the whole forest in the Andes and 1368–1393 years for only Fitzroya in this site. Our biomass estimates for the Andes place these ecosystems among the most massive forests in the world. Differences in biomass production between sites seem mostly apparent as differences in allocation rather than productivity. Residence time estimates for Fitzroya are the highest reported for any species and carbon dynamics in these forests are the slowest reported for wet forests worldwide. Although primary productivity is low in Fitzroya forests, they probably act as ongoing biomass carbon sinks on long-term timescales due to their low mortality rates and exceptionally long residence times that allow biomass to be accumulated for millennia.