Andean Forests Research Articles

Reinstatement of the Genus Piofontia: A Phylogenomic-based Study Reveals the Biphyletic Nature of Diplostephium (Asteraceae: Astereae)

A recent phylogenomic study has shown that Diplostephium in its broad sense is biphyletic. While one of the clades comprises 60 species distributed mainly in the Northern Andes, the clade that contains the generic type, Diplostephium ericoides, contains 48 species, and primarily inhabits the Central Andes. Here, I propose to reinstate the generic name Piofontia and transfer to it the species of Diplostephium in the Northern Andean clade. Piofontia consists, then, of 60 species of woody subshrubs, shrubs, and small trees inhabiting high Andean forests and paramos of Costa Rica, Colombia, Venezuela, and Ecuador. A morphological description is provided for the genus Piofontia along with a species list with 60 new combinations. Dysaster cajamarcensis is shown to be a synonym of Diplostephium serratifolium. Finally, a brief discussion about themorphological evolution of South American Astereae is provided.

Prey of the güiña (Leopardus guigna) in an Andean mixed southern beech forest, southern Chile

ABSTRACTWe quantified the güiña diet (Leopardus guigna) by analyzing 39 scats collected during summer–autumn 2001 in an Andean mixed Nothofagus–Lophozonia forest, southern Chile. Five small mammal species, three passerine species, lizards of one genus, and insects of two orders were identified in the scats. Small mammals were the most frequently consumed prey (47% of all identified prey individuals) and constituted most of the biomass contributed by all prey (75%). The arboreal/scansorial small mammals Oligoryzomys longicaudatus, Irenomys tarsalis, and Dromiciops gliroides were the most frequently consumed vertebrate prey (14.4, 11.5 and 11.5% of all identified prey individuals; 22.7, 21.5 and 18.2% of biomass contributed by all prey, respectively). The frequency of each small mammal species in the scats was not reflected in its respective capture-frequency as evaluated by live-trapping. O. longicaudatus, I. tarsalis, and D. gliroides were ‘overconsumed’ regarding their capture-frequency. Akodon longipilis, the most frequently captured species, was not found in the scats. As a whole, the arboreal/scansorial small mammals were preyed upon by güiñas much more than expected given their capture-frequency. Our results suggest that the güiña is a predator partially specialized for arboreal/scansorial small mammal species, being able to take alternative prey when available.

Alometric model to estimate the potential of carbure capture in Polylepis spp in Poccrac, Ancash 2016

In the following study, allometric equations have been generated to estimate the aerial forest biomass of two species: Polylepis incana and Polylepis sericea, from an Andean natural forest located in the village of Poccrac, in the heights of Ticapampa, Ancash.The allometric equations for both species have been designed from 15 data, relating the biomass (M) as a dependent variable with the diameter of breast height as an independent variable (DAP). The DAP measurement of the selected Polylepis trees are within the range of 5 cm to 20 cm. In the regression analysis performed with the statistical program SPSS V 22.0, a correlation coefficient of r2 = 0.929 is found for the Polylepis incana species and a r2 = 0.94 for the Polylepis sericea species, which indicates a high relation between the biomass variables and DAP, showing good goodness of fit for the parameters that constitute the allometric equation of both species.The results obtained constitute an important methodological contribution for the estimates of carbon capture in areas destined for conservation and a tool to assess the CO2 capture function in Andean forests

Estructura poblacional y distribución espacial del roble negro (Colombobalanus excelsa, Fagaceae), especie endémica, en fragmentos de bosque andino colombiano

Population structure and spatial distribution of black oak (Colombobalanus excelsa, Fagaceae), endemic species, in Colombian Andean forest fragments. The Colombian Andean forests are recognized for its great biodiversity and endemism; however, they have undergone a severe process of fragmentation due to anthropic factors. As a result, many vulnerable species have been especially affected. That is the case of the black oak (Colombobalanus excelsa (Lozano, Hern. Cam., & Henao) Nixon & Crepet), an endemic and poorly studied species of the Colombian Andes, which has a distribution restricted to only four areas in the country, one of which is the Southeastern Huila region. To examine black oak populations in Serranía Peñas Blancas (Huila), in 2006 we studied the age structure and spatial distribution in plots of 50 x 20 m (1.6 ha) in forest fragments, in southern distribution. In total, 1 228 black oak species were registered among saplings, juvenile and adults, and they have distribution patterns Gamma and Weibull. These results confirm that the majority of the individuals are in the first diametric class. Also, these populations show an added distribution pattern due to the wood extraction process. These results indicate that black oak populations are in a recovery phase after forceful anthropic intervention. Knowing the current status of black oak forests can contribute to the design of effective conservation plans of this species in Colombia. Rev. Biol. Trop. 66(2): 486-494. Epub 2018 June 01.

Tropical ash (Fraxinus udhei) invading Andean forest remnants in Northern South America

IntroductionExotic invasive species represent a major driver of the loss of biological diversity and services provided by ecosystems globally. An important cause of species becoming invasive is the development of commercial afforestation projects using fast-growing and adaptable exotic species, which may become invasive impacting natural environments. The tropical ash (Fraxinus uhdei), native to México, has been widely introduced to Colombia and other countries for timber, live fences, and urban greening. It is now common in many areas of the tropical mountains and has been observed expanding into native forests in Colombia.This study examined the invasion pattern and the demographic structure of tropical ash in remnant Andean forests in Colombia, to find out factors associated with the invasion process. The analysis took into account biotic and physical factors: distance to propagule source, vegetation cover types, and understory and canopy cover.ResultsAlthough the reproductive strategy of the tropical ash is of “r” type with low survival rates, the results show evidence for an active process of invasion characterized by an aggregated distribution pattern dominated by seedlings and juvenile plants. The study shows the existence of an interaction between the distance to propagule source and the vegetation cover, which has an additive effect on the demographic structure of the population.ConclusionsThis study suggests an active invasion process by the exotic tree tropical ash into a remnant of sub-humid forests in the Andean highlands. Our results showed an expanding population process with a decreasing average age from propagule sources and mature reproductive individuals within the native forest, which bring new individuals that are colonizing new areas and advancing into the forest. This research points to the need for urgent plant intervention on two aspects: the use of the tropical ash and the management of the invasion process in native forests.

Ethnobotany of the Sierra Nevada del Cocuy-G\xfcic\xe1n: climate change and conservation strategies in the Colombian Andes

BackgroundThe Sierra Nevada del Cocuy-Güicán in the Colombian Andes is protected as a National Natural Park since 1977 because of its fragile páramo ecosystems, extraordinary biodiversity, high plant endemism, and function as water reservoir. The vegetation on this mountain is threatened by expanding agriculture, deforestation, tourism, and climate change. We present an ethnobotanical inventory among local farmer communities and discuss the effects of vegetation change on the availability of useful plants.MethodsWe used 76 semi-structured, 4 in-depth interviews, and 247 botanical collections to record the ethnoflora of the farmers and surveyed from the high Andean forest to the super-páramo, including native and introduced species. We organized 3 participative workshops with local children, high school students, and campesinos’ women to share the data we acquired in the field and empower local plant conservation awareness.ResultsWe encountered 174 useful plants, most of them native to the area (68%) and almost one third introduced (32%). The Compositae was the most species-rich family, followed by Lamiaceae, Poaceae, and Rosaceae. The majority of plant species were used as medicine, followed by food, firewood, and domestic tools. Local farmers reported declining numbers of páramo species, which were now only found at higher altitudes than before. Although our informants were worried about the preservation of their natural resources and noticed the effects of climate change, for several commercial species, unsustainable land use and overharvesting seemed to be the direct cause of declining medicinal plant resources rather than climate change.ConclusionsWe recommend conservation plans that include vegetation monitoring, people’s perceptions on climate change, and participative actions with the communities of the Sierra Nevada del Cocuy-Güicán.

Identificación y cuantificación de los procesos de cambio de las coberturas sobre el territorio de la cuenca alta del río Bogotá, entre 1977 y 2015

La cuenca alta del río Bogotá es considerada un área estratégica del país por la vocación agrícola de sus suelos, al igual que por su alta calidad paisajística y red hidrográfica que se sustenta en ecosistemas naturales particulares, entre ellos los páramos, bosques andinos y humedales. Sin embargo, últimamente la calidad del paisaje se ha visto afectada y las coberturas, tradicionalmente agrícolas y de vegetación natural, han sido sustituidas por otras de tipo industrial, comercial y habitacional, lo cual amerita ser cuantificado en un periodo de tiempo específico, en contexto con la normatividad actual. El presente estudio realizó la identificación y cuantificación de cambios en las coberturas sobre dicho territorio, entre 1977 y 2015, igualmente se calcularon tasas de cambio, deforestación y pérdida de coberturas vegetales naturales. Los resultados evidencian que en este periodo el 70,54 % del territorio se ha trasformado, el 1,93 % fue alterado, el 0,53 % está en degradación y el 26,72 % presenta aún conservación de áreas naturales. Por otra parte, las coberturas de bosques naturales disminuyeron cerca de 38.681,39 ha. La deforestación total anual promedio en un periodo de 38 años fue de 1.017,93 ha/año para el bosque nativo. La tasa de deforestación de bosque nativo es de -1,54 %. La tasa de pérdida de páramo es de -0,16 %, la de los matorrales es de - 3,03 % y la de la vegetación subxerófita es de -1,56 %.

Composition, trophic structure and activity patterns of the understory bats of the Bitaco Forest Reserve

En el presente trabajo se describe la composición y estructura trófica, y se evalúa el efecto de la temperatura ambiental y la precipitación sobre el patrón de actividad nocturna de los murciélagos de sotobosque que habitan que un bosque Andino, para la primera mitad de la noche. Para esto se realizaron siete campañas de muestreo, con una duración de seis noches cada una, en las que se utilizaron diez redes de niebla que operaron entre las 18:00 y 00:00 horas, siendo revisadas cada hora. Además, se registró la temperatura ambiental y la precipitación durante los eventos de muestreo. El ensamblaje de murciélagos de sotobosque del área de estudio estuvo representado principalmente por especies frugívoras, y dentro de este gremio, se registró una menor riqueza de especies nómadas que sedentarias. La actividad de los murciélagos, para la primera mitad de la noche, fue máxima entre las 18:00 y 19:00 horas, disminuyendo hasta alcanzar una actividad mínima entre las 22:00 y 23:00 horas. El modelo más adecuado para explicar la variación en las capturas de murciélagos incluyó sólo el efecto de la temperatura ambiental, la cual afectó positivamente el número de capturas. En conclusión, para el periodo evaluado, la actividad del ensamble de murciélagos de sotobosque en el área de estudio no se relacionó con la precipitación y exhibió relación leve pero significativa con la temperatura ambiental.

Soil changes associated with land use in volcanic soils of Patagonia developed on dynamic landscapes

This paper aimed to identify indicators of soil degradation in volcanic soils developed in the ecotone between the Andean Forests and the Patagonian steppe. The study area is located in the Percy River Basin, Argentine, on alluvial fans with volcanic soils. Sampling was conducted in two adjacent hillslopes where native forest was replaced by a rangeland with grass-shrub vegetation and a 32-years old Pinus radiata plantation. Sectioned and bulk soil samples were collected along three transects in each land cover up to 40 cm depth. Two forest patches of Maytenus boaria were selected as controls. Physical, chemical and magnetic properties were analyzed. Native forest soils were rich in silt fraction, organic matter and non-crystalline minerals, and presented the lowest values of magnetic susceptibility. Rangeland and plantation soils differed from forest soils in these properties. Soil changes were mainly associated to changes in mineralogy resulting from soil desiccation and to the selective removal of fine particles by erosion, together with differences in the effects of recent volcanic events on the soils. Changes in soils associated with land use affected key properties related to pedogenetic processes. Magnetic susceptibility, organic matter content, texture, and pH NaF were key for understanding soil degradation processes in this dynamic environment.

Symplocos ståhlii Kottaim., a new name for extant Symplocos globosa B.Ståhl (Symplocaceae)

Symplocos Jacquin (1760: 24) is the largest genus in the family Symplocaceae and comprises about ca. 340 species (Fritsch et al. 2008). It is distributed in the tropical and subtropical regions of eastern and southeastern Asia, the Americas and Australia (Nooteboom 2004). The genus Symplocos Jacq. is known to have 33 species in Ecuador (Ståhl 2010; Ulloa et al. 2015), the majority of which occur in Andean forests (Ståhl 1995). While revising the genus Symplocos in Ecuador, Ståhl (1991) described 15 new species. Among these, the name S. globosa B.Ståhl (1991: 27) is illegitimate, being a later homonym (Art. 53.1 of the ICN; McNeill et al. 2012) of the fossil taxon S. globosa R. Ludwig (1857: 98). Therefore, the new name Symplocos ståhlii Kottaim. is proposed here as a replacement name for the extant S. globosa.

Four New Species of Dragon's Blood Croton (Euphorbiaceae) from South America

We describe and illustrate four new species of dragon's blood trees (Croton sect. Cyclostigma) from western South America. Three of the species, Croton beckii from Bolivia and Peru, C. camposii fromPeru, and C. santamartensis fromColombia, grow inmontane Andean forest,whereas C. tumbesinus occurs in dry forest of the Tumbes/Piura ecoregion of western Ecuador and Peru. The characters that place them in Croton sect. Cyclostigma include the arborescent habit, the presence of reddish to yellowish latex, an indument of stellate trichomes, conspicuous and persistent stipules, acropetiolar/basilaminar nectary glands, and terminal inflorescences with bisexual cymules at the base. These new species give additional support for the Andean region being the main center of diversity of this Neotropical Croton clade, as well as being a region whose biodiversity knowledge is still incomplete.

Aplicación del protocolo CERA-S para determinar la calidad ecológica de la microcuenca Mamarramos (cuenca Cane-Iguaque), Santuario de Fauna y Flora Iguaque (Boyacá), Colombia 

The protection and conservation of rivers inside protected areas and aquifer recharges are of great importance in Colombia and one of the major commitments of the government, since surface water bodies usually originate in these ecosystems. Such systems therefore offer goods and services of water supply to large cities. The Santuario de Fauna y Flora Iguaque (SFFI) is a protected area of the Colombian Andean region composed of paramo and Andean forest ecosystems. The area, which provides water to both rural and urban communities, is managed by Parques Nacionales Naturales de Colombia (National Natural Parks of Colombia). In order to determine the ecological quality of the Mamarramos micro-basin, the CERA-S protocol (Simplified Ecological Quality for Andean Rivers) was applied. This tool integrates hydro-morphological quality with biotic index ABI. Three samplings were performed during dry season (October, November, and December 2015) in 10 sampling sites along the brooks of Carrizal, Francos, and Mamarramos. Obtained results qualify the micro-basin as a system in excellent state, thus providing valuable information for political and community leaders to make decisions to conserve and prevent the detriment of the ecosystem due to anthropic activities.

Late Holocene wet/dry intervals from Fuegian steppe at Laguna Carmen, southern Argentina, based on a multiproxy record

Late Holocene environmental conditions are reconstructed from a sedimentary core (LCTF2) retrieved from Laguna Carmen (53° 40′ 60″S, 68° 18′ 0″W, 29 m a.s.l.) in the Fuegian steppe, northern Tierra del Fuego, southern Argentina. The multiproxy study utilizes pollen/spores, algae, ostracods, palynofacies, Total Organic Carbon (TOC), carbonate content, and lithology. Findings show that grass communities developed over the landscape from 4200 to 1400 cal yr BP. After that, the plant communities fluctuated between grasses to scrubland vegetation. Changes in the lake level as indicated by the halophytes, algal content and ostracod associations, revealed alternation of wet and dry intervals. The palynofacies indicate environments close to the terrestrial source with a great input of terrigenous organic matter into the lake in agreement with the sedimentary environment. By comparison with other sites from Tierra del Fuego and southwestern Patagonia, the record of wind-carried Nothofagus pollen is consistent with variations in the Andean forest communities as a consequence of shifts in the latitudinal position and/or strength of the westerlies. The short-term wet/dry intervals seem to be associated with climate events of local occurrence. On the other hand, some wet intervals have been reported in lacustrine records from southern Patagonia. The last millennium showed high environmental variability. Humid conditions characterized the Medieval Climate Anomaly (MCA) event, while dryness conditions were related to the Little Ice Age (LIA) event. In particular this latter interval has been related to a northward migration of the westerlies from their present day focus.

Phylogenetic relationships and generic reassessment of Proustia and allies (Compositae: Nassauvieae)

AbstractProustia is a small southern Andean genus of shrubs, vines and small trees, which are characteristic elements of Chilean and Argentine Andean forests, thickets and desert scrubs. Since Proustia possesses an unusual and characteristic morphology within the Nassauvieae, its circumscription as well as its phylogenetic placement is decisive in understanding the evolution of the tribe. Berylsimpsonia, from the Caribbean, was segregated from Proustia, which currently only includes three species. Lophopappus, another Andean genus, has been closely related to Proustia in sharing style and corolla features that are unusual in the Nassauvieae. The purpose of this work is to evaluate the placement of Proustia within the Nassauvieae, its relationships with Berylsimpsonia and Lophopappus, and the relationships of its species using molecular data and phylogenetic methods. This is the first comprehensive analysis of Proustia. We have included in our study the three currently accepted species of Proustia and seven of its ten infraspecific taxa. For each taxon of Proustia, one to seven accessions were analyzed. Species of Lophopappus and Berylsimpsonia, as well as 16 species belonging to 13 genera of Nassauvieae were also analyzed. We sequenced the nuclear ribosomal ITS and ETS, and the plastid regions ndhF, 5’ trnK–matK, trnL–trnF, and trnL(UAG)–rpl32. Unlike other previous studies, Proustia is not sister to the rest but nested in the tribe in our analyses. Berylsimpsonia vanillosma and P. ilicifolia are distantly related to P. pyrifolia, the type of the genus. According to nuclear DNA data, the infraspecific taxa of P. cuneifolia were recovered all in a well–supported clade, although based on the plastid data P. pyrifolia does not form a lineage separate from P. cuneifolia. Lophopappus is the genus most closely related to Proustia. Regarding the evolution of styles, our results suggest multiple origins of atypical stylar features in the Nassauvieae. As a result of our analyses we propose the segregation of Proustia ilicifolia into the new genus Spinoliva. Morphological data are consistent with the segregation of Proustia and Lophopappus as separate genera. Two species of Proustia, P. cuneifolia and P. pyrifolia are recognized. Three lectotypifications, one neotypification, two new combinations and five rank changes are proposed.

An evaluation of physical and mechanical scarification methods on seed germination of Vachellia macracantha (Humb. & Bonpl. ex Willd.) Seigler & Ebinger

Los bosques secos andinos son ecosistemas con alta diversidad de flora y fauna y tienen alto riesgo de extinción debido a la presión de la actividad humana. V. macracantha es una especie nativa del bosque seco andino que tiene potencial para la reforestación y también brinda beneficios en sistemas agroforestales, debido a su capacidad de fijación de nitrógeno, el suministro de materia orgánica, la producción de sombra y protección del viento. La propagación de esta especie es limitada debido al bajo porcentaje de germinación de las semillas, las cuales presentan dormancia. El propósito de esta investigación fue determinar el método de escarificación más eficaz para la germinación de las semillas de V. macracantha. Dos tipos de métodos fueron probados, la inmersión en ácidos fuertes (escarificación química), y la remoción de la corteza de la semilla a través del limado, corte y remojo en agua caliente (escarificación física). Se utilizó un diseño de bloques completamente al azar con 3 repeticiones. Para los métodos químicos, se usó ácido sulfúrico, nítrico, y fosfórico (50% v/v) a diferentes tiempos de exposición: 5, 10, 15, 20 y 25 minutos, respectivamente. Se midieron tres variables como sigue: porcentaje de germinación, la cantidad de hojas y la altura de la planta. Los métodos químicos no presentaron ninguna diferencia significativa en el porcentaje de germinación. El método físico de limado de la semilla tuvo el porcentaje más alto de germinación con un 46%, en comparación al control que tuvo el 6%. Ningún tratamiento tuvo diferencias significativas en los parámetros de cantidad de hojas y la altura de la planta.

Riqueza total de especies de plantas vasculares en un bosque andino de la Cordillera central de Colombia

Studies of plant diversity in tropical forests are usually restricted to trees or other groups of woody plants above a certain stem diameter. However, surveys that include all forms of live plants with no restrictions on their sizes, clearly indicate that non-woody plants are equally important. In this study, we reported the total species richness of vascular plants species (TSR) in one hectare plot in an Andean forest in Northwestern Colombia (6º 12' 48” N & 75º 29' 32” W). We evaluated the relative contribution of the different growth habits and the effect of the plant size, to TSR. We measured all individuals with diameter (D) ≥ 5 cm in the hectare and all the vascular plants of all sizes, including epiphytes, in a subsample of 0.25 ha. A total of 14 545 individuals distributed in 318 species, 72 families (considering Pteridophyta as one group) and 171 genera were registered. Most of the species showed a (D) < 10 cm (99.7%) and < 2.5 cm (94.4 %). The no-arboreal species (ground herbs, epiphytes and vines) represented 54.3 % of the total species reported in the plot, indicating that they are important in the structure, composition and species richness of this montane forest. Our results coincide with similar studies in other tropical forests. We concluded that to get a more detailed knowledge of the floristic diversity of a site, it is advisable to: 1) amplify the size range of the plants generally considered in the floristic inventories and 2) to include non-woody species. This information is crucial for making better decisions in local and global conservation efforts.

What controls variation in carbon use efficiency among Amazonian tropical forests?

AbstractWhy do some forests produce biomass more efficiently than others? Variations in Carbon Use Efficiency (CUE: total Net Primary Production (NPP)/ Gross Primary Production (GPP)) may be due to changes in wood residence time (Biomass/NPPwood), temperature, or soil nutrient status. We tested these hypotheses in 14, one ha plots across Amazonian and Andean forests where we measured most key components of net primary production (NPP: wood, fine roots, and leaves) and autotrophic respiration (Ra; wood, rhizosphere, and leaf respiration). We found that lower fertility sites were less efficient at producing biomass and had higher rhizosphere respiration, indicating increased carbon allocation to belowground components. We then compared wood respiration to wood growth and rhizosphere respiration to fine root growth and found that forests with residence times <40 yrs had significantly lower maintenance respiration for both wood and fine roots than forests with residence times >40 yrs. A comparison of rhizosphere respiration to fine root growth showed that rhizosphere growth respiration was significantly greater at low fertility sites. Overall, we found that Amazonian forests produce biomass less efficiently in stands with residence times >40 yrs and in stands with lower fertility, but changes to long‐term mean annual temperatures do not impact CUE.

Vegetation responses to late Holocene climate changes in an Andean forest

AbstractA paleoecological record from Lake Palotoa (1370 m elevation) in the Andean foothills of Peru spans the last 3800 years. Lake Palotoa lies near the modern cloud base in a location sensitive to changes in atmospheric moisture. In many areas, these forests have been destroyed, but Lake Palotoa shows no sign of human occupation today or in the past. The modern forest surrounding the lake is dominated by the Andean palm, Dictyocaryum lamarckianum, which is also the most abundant taxon in the fossil pollen record. Fossil pollen data show the vegetation assemblages have not experienced strong compositional changes in the late Holocene. Global-scale climatic events such as the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) are identified within the record, though the vegetation responses are subtle. Hedyosmum and Sloanea pollen percentages increase near the onset of the MCA and may reflect decreased seasonality. The LIA coincides with increased Hedyosmum pollen percentages, and increases in Clethra and Begonia, two elements that tend to occupy forests now found at higher elevations. Our findings demonstrate the stability of montane forest systems to natural Holocene climate change.

Spatial and temporal distributions of exotic and local obsidians in Central Western Patagonia, southernmost South America

Central Western Patagonia (CWP) is a key area for assessing long-distance procurement of high-quality obsidians throughout the Holocene given that almost all relevant types represented in the archaeological record are exotic to this region. By using surface and stratigraphic obsidian artifacts from archaeological sites compared to standards from known sources in Patagonia, this paper discusses the spatial and temporal distribution of this lithic material. Sampling was oriented to assemblages from deposits with radiocarbon-based time frames (10,700 − 300 cal BP). This paper presents geochemical (ICP-MS) analyses of 178 samples from 58 archaeological sites at 11 surveyed areas located along the Pacific coast, the Andean forest, and eastern steppe. Out of six potential sources, the Chaitén Volcano source (Los Lagos Region, Chile) dominates exclusively the occurrence of obsidians along the coastal fringe, while the Pampa del Asador source (PDA, Santa Cruz Province, Argentina) largely dominates (86% of samples) obsidian in the eastern steppe and the forest/steppe ecotone. This broad distribution is explained by the presence of the densely forested Andean mountain range acting as a biogeographical barrier. East of the Andes, we recorded an absolute dominance of PDA south of 45°30′S, while more variability prevailed north of this point. The highest diversity of obsidians was recorded in the Cisnes River valley, probably because it is located closer to other alternative northern sources (Telsen/Sierra Negra, Sacanana and Angostura Blanca, all in Chubut Province, Argentina) and because it also hosts a local low-quality obsidian type. Based on this distribution, we discuss obsidian procurement behaviors by considering obsidian frequency and tool/debitage-class representation with increasing distance. We use the analysis of fall-off curves based on the distance of studied locations from the sources and include the use of least-cost paths for providing the most likely procurement routes. No obsidian diversification was recorded during the Holocene, hence the main driver for its procurement seems to be the distance from the source rather than the antiquity of its knowledge. Alternative procurement behaviors are discussed, specifically direct acquisition, exchange, and/or sporadic visits as mechanisms for explaining the archaeological patterns throughout the Holocene.

Nesting Biology of the Sooty Antibird (Hafferia fortis) In Southeastern Peru

ABSTRACT The Sooty Antbird (Hafferia fortis) inhabits Andean foothills and lowland humid forest from Colombia to the western Brazilian Amazon. Despite its wide distribution, many natural history aspects are poorly known. The nest, eggs, and nestlings are described, with no additional nesting information available. Our study provides detailed behavioral information on the nesting biology of H. fortis based on seven nests that were monitored in lowland humid forest in southeastern Peru. Nests were large domes found mostly on slopes or in ravines. The clutch size was always two eggs. Both sexes share daytime incubation and feed the nestlings, but the female exclusively conducted nighttime incubation and brooding. Daytime nest attentiveness was 83 ± 9.5% (SD; n = 13 days), and was similar in both sexes. Nestling period was 13 days, and adults conducted 3.86 feeding trips per day, which increased as nestling developed. Nesting characteristics observed in H. fortis are similar to other Hafferia species, althoug...