Natalia Politi

Universidad Nacional de Jujuy, Facultad de Ciencias Agrarias, Faculty Member

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Ecología y conservación del Loro Alisero (Amazona tucumana)

El Hornero

El Loro Alisero (Amazona tucumana) es endémico de las selvas subtropicales de montaña del noroest... more El Loro Alisero (Amazona tucumana) es endémico de las selvas subtropicales de montaña del noroeste de Argentina y sur de Bolivia (Yungas Australes). En este trabajo se recopila información publicada y novedosa sobre aspectos ecológicos y de conservación del Loro Alisero. Se registró al Loro Alisero consumiendo semillas, frutos y flores de 18 especies nativas y 5 exóticas. Se identificaron nidos en 10 especies de árboles distribuidos entre los 1470–2200 msnm y se encontró una alta variabilidad en la densidad de nidos. Se detectaron seis dormideros que albergan la totalidad o una buena parte de las poblaciones de un área, por lo que una buena estrategia de monitoreo de sus poblaciones sería realizar conteos en ellos todos los años, de manera de tener una estimación de las tendencias poblacionales a largo plazo. Fueron registrados 7650 individuos en 26 sitios en Argentina y Bolivia. Es probable que el tamaño poblacional actual sea menor que el anterior a la década de 1980, cuando las c...

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Vegetation greenness and thermal heterogeneity as proxies of climate change resilience in Argentina

Preliminary assessment of the conservation status of timber species in the threatened piedmont dry forest of northwestern Argentina

Journal for Nature Conservation, 2021

Abstract The piedmont dry forest of northwestern Argentina has been under intensive and unplanned... more Abstract The piedmont dry forest of northwestern Argentina has been under intensive and unplanned forest logging focused on 12 tree species, without any attempts having been made to ensure their regeneration or long-term conservation. In this study, we assessed the conservation status of these timber species in the piedmont dry forest of northwestern Argentina and compared our results with the IUCN assessment. We considered an inadequate conservation status if the species: (1) occurred in less than 50% of the sampled plots, (2) had a density of large trees (more than 40 cm DBH) lower than one individual per hectare, or (3) had a density of saplings (more than 30 cm in height and less than 9.9 cm in DBH) lower than 30 in.ividuals per hectare. Our results showed an inadequate conservation status for eight of the 12 studied timber tree species. Additionally, only seven species were previously assessed and categorized on the IUCN Red List, with our categorization agreeing with only four of them. The data provided in this work can serve as a baseline to monitor the population trends of these species; information can also help to prioritize conservation efforts, which is essential considering the high number of tree species that have potential extinction risk in the short-term.

Tree Use, Niche Breadth and Overlap for Excavation by Woodpeckers in Subtropical Piedmont Forests of Northwestern Argentina

Acta Ornithologica, 2020

Studies dealing with the selection of tree species and characteristics for cavity-nesting birds a... more Studies dealing with the selection of tree species and characteristics for cavity-nesting birds are important to evaluate the abundance and quality of available resources in the environment. The aim of this study is to characterize the use of trees by woodpecker species in the subtropical piedmont forests of northwestern Argentina by using the analysis of niche selection, breadth and overlap in a total of five woodpecker species of different body size found in these subtropical forests: White-barred Piculet Picumnus cirratus (small woodpeckers), Golden-olive Woodpecker Colaptes rubiginosus, Golden-green Woodpecker Piculus chrysochloros, Dot-fronted Woodpecker Veniliornis frontalis (medium-sized woodpeckers), and Cream-backed Woodpecker Campephilus leucopogon (largest woodpeckers). From a total of 54 tree species, only 15 were used by these woodpecker species. Primary excavator species were moderate specialists in tree use (Levin's index), and they showed selection according to their availability (Ivlev's index) of four of the fifteen tree species (Calycophyllum multiflorum, Amburana cearensis, Cedrela balansae, Astronium urundeuva) and snags. There was a high overlap (Morisita's overlap index) in the use of tree species between Picumnus cirratus and medium-sized woodpeckers, while less overlap was found between Campephilus leucopogon and other woodpecker species. Both living trees and snags were used by the woodpeckers, although snags were more important for small and medium-sized woodpeckers, whereas living trees were more important for Campephilus leucopogon. Both snags and living trees had a large diameter at breast height (DBH) in > 50 cm. Results show the existence of different cavity-excavation niches for woodpecker species in subtropical forests of Argentina, and they allow us to identify the important relationships between these birds and the available tree species. Thus, the results of this work may be useful to develop sustainable forest management guidelines for this group of birds.

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Consumo de frutos de cactáceas por el carpintero lomo blanco (Campephilus leucopogon) en el noroeste argentino

Fil: Vivanco, Constanza Guadalupe. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andin... more

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Influence of logging on nest density and nesting microsites of cavity-nesting birds in the subtropical forests of the Andes

Forestry: An International Journal of Forest Research, 2021

Birds select nesting sites with certain characteristics associated with tree age and species that... more Birds select nesting sites with certain characteristics associated with tree age and species that help to prevent or reduce the risk of clutch loss due to predation or unfavourable weather conditions. Logging may reduce the availability of trees and their related features that may be important for cavity nesters. Thus, the aim of this study is to evaluate the effect of logging on nest density, nesting microsite and nest success of cavity nesting birds at Piedmont forests of northwestern Argentina. We monitored these variables at different logged and unlogged sites during four consecutive reproductive seasons and analysed them using univariate analysis and generalized linear models. The main results indicate that logging reduces nest density and changes the characteristics of the nesting microsites. We found that nest success was greater in cavities located higher above the ground and found no evidence of lower nest success at logged sites. This study suggests the need for forest man...

Use of response guilds of understory birds in threatened subtropical forest to monitor selective logging impact

Ecological Indicators, 2021

Latitude does not influence cavity entrance orientation of South American avian excavators

The Auk, 2021

In the Northern Hemisphere, several avian cavity excavators (e.g., woodpeckers) orient their cavi... more In the Northern Hemisphere, several avian cavity excavators (e.g., woodpeckers) orient their cavities increasingly toward the equator as latitude increases (i.e. farther north), and it is proposed that they do so to take advantage of incident solar radiation at their nests. If latitude is a key driver of cavity orientations globally, this pattern should extend to the Southern Hemisphere. Here, we test the prediction that cavities are oriented increasingly northward at higher (i.e. colder) latitudes in the Southern Hemisphere and describe the preferred entrance direction(s) of 1,501 cavities excavated by 25 avian species (n = 22 Picidae, 2 Trogonidae, 1 Furnariidae) across 12 terrestrial ecoregions (15°S to 55°S) in South America. We used Bayesian projected normal mixed-effects models for circular data to examine the influence of latitude, and potential confounding factors, on cavity orientation. Also, a probability model-selection procedure was used to simultaneously examine multipl...

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Informing forest conservation planning with detailed human footprint data for Argentina

Global Ecology and Conservation, 2021

Conserving the remaining wildest forests is a top priority for conservation, and human footprint ... more Conserving the remaining wildest forests is a top priority for conservation, and human footprint maps are a practical way to identify wild areas. However, available global assessments of wild areas are too coarse for land use decisions, especially in countries with high deforestation rates, such as Argentina. Our main goal was to map the human footprint in Argentina's forested areas to improve conservation planning at regional and country levels. Specifically, we quantified the level of human influence on the environment and mapped the wildest native forests (i) across forest regions, and (ii) in the different land-use categories of the National Forest Plan, which is a key policy instrument for conserving the nation's native forests through zoning, and (iii) identified wildest forests that are at risk due to human activities. We analyzed detailed spatial data on settlements, transportation, energy, and land use change, and estimated the areal extent to which these various human activities disrupt natural processes. We defined pixels with human footprint index of zero as wildest areas. We found that a substantial portion (43%) of Argentina's forested area remains wild, which suggests there are opportunities for conservation. However, levels of human influence varied substantially among forest regions, and Atlantic and Chaco forests have the highest levels of human influence. Further, we found that the National Forest Plan does not conserve the wildest forests of the nation, as most (78%) of the wildest native forests are located in zones that allow silvopasture, timber production, and/or forest conversion to crops, thus potentially threatening biodiversity in these areas. Our map of wildest forests is an important, but first, step in identifying wildland forests in Argentina, as available spatial data layers of human activities capture many, but not all, human influences on forests. For instance, small human features, like certain rural roads, trails, and rural settlements exist in our wildest areas. Our study provides new datasets to assist land use planners and conservationists, and identifies areas for * Corresponding author.

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Spatio-temporal remotely sensed indices identify hotspots of biodiversity conservation concern

Remote Sensing of Environment, 2021

Abstract Over the course of a year, vegetation and temperature have strong phenological and seaso... more Abstract Over the course of a year, vegetation and temperature have strong phenological and seasonal patterns, respectively, and many species have adapted to these patterns. High inter-annual variability in the phenology of vegetation and in the seasonality of temperature pose a threat for biodiversity. However, areas with high spatial variability likely have higher ecological resilience where inter-annual variability is high, because spatial variability indicates presence of a range of resources, microclimatic refugia, and habitat conditions. The integration of inter-annual and spatial variability is thus important for biodiversity conservation. Areas where spatial variability is low and inter-annual variability is high are likely to limit resilience to disturbance. In contrast, areas of high spatial variability may be high priority candidates for protection. Our goal was to develop spatio-temporal remotely sensed indices to identify hotspots of biodiversity conservation concern. We generated indices that capture the inter-annual and spatial variability of vegetation greenness and land surface temperature and integrated them to identify areas of high, medium, and low biodiversity conservation concern. We applied our method in Argentina (2.8 million km2), a country with a wide range of climates and biomes. To generate the inter-annual variability indices, we analyzed MODIS Enhanced Vegetation Index (EVI) and Land Surface Temperature (LST) time series from 2001 to 2018, fitted curves to obtain annual phenological and seasonal metrics, and calculated their inter-annual variability. To generate the spatial variability indices, we calculated standard deviation image texture of Landsat 8 EVI and LST. When we integrated our inter-annual and spatial variability indices, areas in the northeast and parts of southern Argentina were the hotspots of highest conservation concern. High inter-annual variability poses a threat in these areas, because spatial variability is low. These are areas where management efforts could be valuable. In contrast, areas in the northwest and central-west are where protection should be strongly considered because the high spatial variability may confer resilience to disturbance, due to the variety of conditions and resources within close proximity. We developed remotely sensed indices to identify hotspots of high and low conservation concern at scales relevant to biodiversity conservation, which can be used to target management actions in order to minimize biodiversity loss.

Human footprint defining conservation strategies in Patagonian landscapes: Where we are and where we want to go?

Journal for Nature Conservation, 2021

Understanding human influence on ecosystems and their services is crucial to achieve sustainable ... more Understanding human influence on ecosystems and their services is crucial to achieve sustainable development and ensure the conservation of biodiversity. In this context, the human footprint index (HFI) represents the anthropogenic impacts on ecosystems and the natural environment. Our objective was to characterize the HFI in Southern Patagonia (Argentina) across the landscape, qualifying the differences among the main ecological areas and especially the forested landscapes. We also assessed the potential utility of HFI to identify priority conservation areas according to their wilderness quality and potential biodiversity values. We created a HFI map (scores varied from 0 representing high wilderness quality to 1 representing maximum human impact) using variables related to direct (e.g. infrastructure) and indirect (e.g. derived from economic activities) human impacts, including settlements, accessibility, oil industry, and sheep production. HFI varied significantly across the natural landscapes, being lower (0.07-0.11) in remote ecosystems close to the Andes Mountains and higher (0.38-0.40) in southern areas close to the provincial capital city. Forested landscapes presented different impact values, which were directly related to the economical values of the different forest types. We determined that the current protected area network is not equally distributed across the different ecological areas and forest types. Priority conservation areas were also identified using the fragmentation produced by the human impact, the patch size, and the potential biodiversity values. HFI can present high compatibility with other land-use management decision making tools, acting as a complement to the existing tools for conservation planning or management.

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Feeding Ecology and Key Food Resources for the Endemic and Threatened Tucuman Amazon Amazona tucumana in Argentina

Acta Ornithologica, 2020

Abstract. Food resource availability regulates population levels and reproductive success in seve... more Abstract. Food resource availability regulates population levels and reproductive success in several parrot species. Of the 59 threatened parrot species in the Neotropics, information on diet is available for only 34. Unsustainable forest management can eliminate trees with seeds and fruits that are key food resources for parrots. Tucuman Amazon Amazona tucumana is an endemic and threatened parrot species categorized as Vulnerable that occurs only in Andean montane forests of northwestern Argentina and southern Bolivia; i.e., the Southern Yungas. The diet of Tucuman Amazon, food availability, specialization, key food resources, and seasonal and spatial variation of food resources were determined. Feeding bouts of Tucuman Amazon were recorded from December 2007 to February 2009 in El Rey National Park. Availability of trees with seeds, fruits or flowers that could be used by Tucuman Amazon as food resources was assessed in phenology plots in cloud forest (high elevation humid forest) and transition forest (semideciduous forest located in the piedmont). Both forest types showed marked seasonality in availability of food resources for Tucuman Amazon. Sixty-six percent of this species feeding bouts were on seeds. Podocarpus parlatorei is the most widely used tree species by Tucuman Amazon in the cloud forest during the reproductive period and Acacia visco in the transition forest in the non-reproductive period. Podocarpus parlatorei could be critical for the development of Tucuman Amazon chicks, due to the high fat and oil content of its seeds and fruits. Tucuman Amazon used fewer food tree species during the non-reproductive than the reproductive period, showing a greater specialization of food resources (i.e., narrower niche breadth). To ensure the production of fruits of P. parlatorei and A. visco, sustainable forest management in the Southern Yungas should retain an adequate level of these key resources for Tucuman Amazon.

Limitantes y avances para alcanzar el manejo forestal sustentable en las Yungas Australes

Ecología Austral, 2019

Hasta la actualidad, los bosques de las Yungas Australes se manejaron sólo para proveer madera de... more Hasta la actualidad, los bosques de las Yungas Australes se manejaron sólo para proveer madera de unas pocas especies arbóreas con alto valor económico. Extracciones sucesivas sin respetar los tiempos de recuperación del sistema llevaron a que una gran proporción de esta ecorregión se encuentre empobrecida y simplificada, lo que hace que estos bosques sean más propensos a ser transformados a otros usos de la tierra. Por esta razón es necesario una pronta adopción de lineamientos de manejo forestal sostenible en las que se incluya el amplio rango de valores que estos bosques proveen (e.g., biodiversidad y servicios ecosistémicos). Actualmente, existen lineamientos para mantener una producción sostenible de madera y disminuir los efectos negativos de la intervención silvícola, y también se dispone de una cantidad de información que permite empezar a delinear pautas de manejo forestal ecológicamente sostenible para otros valores del bosque de las Yungas Australes. Sin embargo, en esta ecorregión, dichos lineamientos fueron en su mayoría ignorados. Opinamos que esto puede deberse a la falta de un adecuado escenario socio-económico y político, enmarcado en una política forestal a largo plazo. Es necesario contar con compensaciones económicas que permitan mejorar la rentabilidad del bosque al incentivar a los propietarios a cambiar a prácticas de manejo forestal sostenible. Otra posibilidad debería ser reconocer y pagar por los diversos servicios ecosistémicos que las Yungas Australes proveen. La implementación de un esquema de manejo forestal sostenible permitirá que estos bosques puedan seguir brindando distintos bienes y servicios que benefician a distintos actores sociales que dependen de las Yungas Australes. [Palabras clave: selvas de montaña, bosque nativo, lineamientos de manejo, política forestal, servicios ecosistémicos, biodiversidad, conservación] ABSTRACT. Limitations and advances to attain sustainable forest management in Southern Yungas of Argentina. Until now, the Southern Yungas forests have been managed only to provide wood from a few economically valuable tree species. Successive reentries without considering the time needed for the ecosystem to recover led to a degradation and simplification of great proportion of the Southern Yungas, making these forests more susceptible to transformation to other land-uses. For this reason, an early adoption of guidelines for sustainable forest management, including the wide range of values that these forests provide (e.g., biodiversity and ecosystem services), is needed. Currently, guidelines to attain a sustainable yield of wood and decrease the negative effects of logging are available, and also a great amount of information has been developed to start delineating sustainable forest management guidelines for other values of the Southern Yungas forest. However, these guidelines have been mainly ignored in the Southern Yungas due to, in our opinion, primarily, a lack of a socio-economic and political scenario framed in a long-term forest policy is set. It is necessary to provide economic compensations that promote land-owners to shift to sustainable forest management activities. An alternative should be to recognize and pay for the diverse ecosystem services that the Southern Yungas provide. To implement sustainable forest management guidelines will ensure that these forests continue providing multiple goods and services that benefit local stakeholders which depend on the Southern Yungas.

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Cavity-tree use and frequency of response to playback by the Tropical Screech-Owl in northwestern Argentina

Neotropical Biology and Conservation, 2019

The Tropical Screech-Owl (Megascops choliba) is a nocturnal raptor with a wide distribution acros... more The Tropical Screech-Owl (Megascops choliba) is a nocturnal raptor with a wide distribution across the Neotropics, which uses cavity trees as nesting and roosting sites. Our objectives were to address cavity use by the Tropical Screech-Owl in the piedmont forest of Argentina and to evaluate if logging affects the availability of suitable cavities for nesting and roosting and the frequency of response of the species to playback. The Tropical Screech-Owl used trees with DBH values > 46 cm of three tree species (69% Calycophyllum multiflorum, 15% Phyllostylon rhamnoides, and 8% Cedrela angustifolia), besides standing dead trees (8%). The density of suitable cavities was significantly lower in logged forests than in the control site. The frequency of response of the species to playback was significantly lower at one logged site. Our results can contribute to delineate sustainable forest management to ensure the conservation of this owl in logged forest.

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The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project

Ecology and evolution, 2017

The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems... more The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international effort...

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Caracterización y selección de sitios de excavación del carpintero lomo blanco (Campephilus leucopogon) en dos regiones forestales del noroeste Argentino

Bosque (Valdivia), 2016

Woodpeckers are considered engineering species of forests and are sensitive to changes in forests... more Woodpeckers are considered engineering species of forests and are sensitive to changes in forests composition and structure. Northwestern Argentina contains the largest area of native forest of the country. The objectives of this study are to characterize sites where the Cream-backed woodpecker (Campephilus leucopogon) excavates its nesting or roosting cavities and identify selection patterns of those sites in the Piedmont forest of the Southern Yungas and Dry Chaco forest of Northwestern Argentina. In both forest regions transects were conducted to search for excavated cavities by the Cream-backed woodpecker. Trees with and without cavities and random plots where characterized. Both in the Piedmont and Chaco forest, most of the excavated cavities found were in live trees of more than 60 cm of diameter at breast height. Excavated cavity height was greater in the Piedmont than in the Chaco forest. The Cream-backed woodpecker selected for excavation Calycophyllum multiflorum and Amburana cearensis in the Piedmont forest and Aspidosperma quebracho-blanco and Chorisia insignis in the Chaco forest. The results obtained in this study allow proposing guidelines on how to improve forest management by retaining key structural attributes for the Cream-backed woodpecker. The species maintenance in managed forest will determine the amount of cavities available for many other non-excavator species.

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Will representation targets based on area protect critical resources for the conservation of the Tucuman Parrot?

The Condor, 2015

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more

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Distinct summer bird assemblages in two fragments of Polylepis forests in the Southern Yungas of Argentina

ORNITOLOGIA NEOTROPICAL

Polylepis forests are considered one of the most threatened Neotropical ecosystems. The tropical ... more Polylepis forests are considered one of the most threatened Neotropical ecosystems. The tropical Andes avifauna of Polylepis forests has been relatively well studied in Bolivia and Peru; however, in Argentina this information is scarce. In this study, we characterize and compare bird assemblages in two humid Polylepis forests fragments of the Southern Yungas, P australis and P. hieronymi, and provide the first exhaustive bird list for P. hieronymi forest. Fieldwork was carried-out in two mountain ranges in Jujuy Province with Polylepis forest dominated by the different species. We recorded a total of 391 birds belonging to 43 species. Bird richness, relative abundance, and diversity were higher in P australis than in P hieronymi forest. There was a high turnover in species composition between communities (Sorensen similarity index = 23%). Indicator species of each forest type were Rufous-collared Sparrow (Zonotrichia capensis, IV = 90%) in P australis and White-crested Elaenia (Elae...

Cambios Inesperados en El Ensamble De Aves en Áreas Bajo Explotación Forestal en La Selva Pedemontana Del Noroeste …

ORNITOLOGIA NEOTROPICAL, 2010

... CAMBIOS INESPERADOS EN EL ENSAMBLE DE AVES EN ÁREAS BAJO EXPLOTACIÓN FORESTAL EN LA SELVA PED... more

The dichotomy between protection and logging of the Endangered and valuable timber species Amburana cearensis in north-west Argentina

Oryx, 2014

Amburana cearensis is a commercially valuable timber species, categorized as Endangered on the IU... more Amburana cearensis is a commercially valuable timber species, categorized as Endangered on the IUCN Red List. It is distributed throughout the seasonal dry tropical forests of Brazil, Paraguay, Bolivia, Peru and Argentina. In Argentina it is restricted to the provinces of Salta, where legislation sets a minimum cutting diameter of 60 cm, and Jujuy, where logging of this species has been banned since 1972. The effect of these laws on the species’ conservation status has not been assessed. We estimated species density, using distance sampling methodology, and measured the diameter at breast height of each individual encountered at 13 sites in north-west Argentina. Across both provinces we found a density of 1.12 individuals ha−1 (95% CI 0.48–2.63) and there was no significant difference between the density in Salta (5.15 ha−1;; 95% CI 3.14–8.45) and that in Jujuy (3.67 ha−1;; 95% CI 2.59–5.17), although 84% of the individuals encountered in Salta were found at one site. Diameter at br...

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