DSpace Angular :: Browsing by Author "Bonacic, Cristian"

Browsing by Author "Bonacic, Cristian"

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A conflict between a threatened deer and indigenous agriculture: Tarukas (Hippocamelus antisensis D'Orbigny) and Aymara farmers in northern Chile
(EDICIONES UNIV, CONCEPCION, 2021) Munoz, Alejandra E.; Petitpas, Robert; Marin, Juan C.; Bonacic, Cristian
The taruka is one of the least known deer species of the world. Its range includes the northern Andean mountains in Chile, where their relationship with Aymara peasants is conflictive because of crop raiding. The aim of this study is to understand the nature of this conflict in Chile, and identify socio-ecological features that may explain it. Data of different sampling dates from 2003 to 2011 of night transects on roads, crop examination, interviews and direct sighting of tarukas were used to understand its ecology and relationship with local peasants. Peasants interviewed (n=47) cultivated mainly corn (85.1%) and alfalfa (74.5%) in small farms and 83% of them raise livestock. The conflict is widespread in Parinacota Province, where tarukas effectively consume crops, mainly abandoned alfalfa at night. The occurrence of crop raiding is not positively correlated with dry season as expected. However crop consumption is low (10.3% average of damaged plants in crop plots). In Del Tamarugal Province only 29.4% of peasants manifested conflict with tarukas but they did report conflict with other ungulates. Day sightings showed 78 tarukas in 34 encounters during 59 days. Night surveys yielded 11.6 +/- 7.4 tarukas/survey, sighted only in alfalfa plots. Aymara agriculture feeds tarukas and is declining because of rural-urban migration. The conflict must be considered in the conservation strategy of the species.
Age and sex structure of Andean Condor (Vultur gryphus) in feeding areas of central Chile
(NEOTROPICAL ORNITHOLOGICAL SOC, USGS PATUXENT WILDLIFE RESEARCH CTR, 2015) Escobar Gimpel, Victor; Alvarado, Sergio; Vargas, Hernan; Bonacic, Cristian
The age and sex structures of the Andean Condor are known for some parts of its range while in other such areas data are lacking. The aim of this study was to obtain demographic data from the Andes of central Chile and to compare them with those available from other areas of distribution. From 2009-2010, we studied the age and sex structure of the Andean Condor in central Chile at feeding sites. Four carrion points were provided by us. The carrion comprised carcasses of sheep, donkey, and guanaco. Condor abundance at experimental carrion (mean = 36.25, SE = 48.45) was highly variable (CV = 134%), and we observed a higher proportion of adults (54%) than immatures (46%). Overall the sex ratio of adults was male-biased (52:48). The age and sex structures in our study are consistent with those found in other areas of the species' distribution. Our results show a higher proportion of adult birds and males at feeding sites in the Andes of central Chile, which has implications on the population viability of the Andean Condor.
Altered fire regimes modify lizard communities in globally endangered Araucaria forests of the southern Andes
(NATURE PORTFOLIO, 2021) Infante, Jose; Novoa, Fernando J.; Ibarra Eliessetch, José Tomás; Melnick, Don J.; Griffin, Kevin L.; Bonacic, Cristian
Wildfire regimes are being altered in ecosystems worldwide. The density of reptiles responds to fires and changes to habitat structure. Some of the most vulnerable ecosystems to human-increased fire frequency are old-growth Araucaria araucana forests of the southern Andes. We investigated the effects of wildfires on the density and richness of a lizard community in these ecosystems, considering fire frequency and elapsed time since last fire. During the 2018/2019 southern summer season, we conducted 71 distance sampling transects to detect lizards in Araucaria forests of Chile in four fire "treatments": (1) unburned control, (2) long-term recovery, (3) short-term recovery, and (4) burned twice. We detected 713 lizards from 7 species. We found that the density and richness of lizards are impacted by wildfire frequency and time of recovery, mediated by the modification of habitat structure. The lizard community varied from a dominant arboreal species (L. pictus) in unburned and long-recovered stands, to a combination of ground-dwelling species (L. lemniscatus and L. araucaniensis) in areas affected by two fires. Araucaria forests provided key habitat features to forest reptiles after fires, but the persistence of these old-growth forests and associated biodiversity may be threatened given the increase in fire frequency.
Behavioural and physiological consequences of capture for shearing of vicunas in Argentina
(ELSEVIER SCIENCE BV, 2010) Arzamendia, Yanina; Bonacic, Cristian; Vila, Bibiana
Behavioural. physical and physiological responses of Argentinean vicunas to capture, handling and shearing were studied for the first time. The research was undertaken in a study area of 2414 ha with a mean density of 12-40 vicunas/km(2). Captures were conducted on groups of wild vicunas that had not received any prior management. Groups were herded into a funnel system that ended in a corral with several internal subdivisions. Three distinct capture methods were compared, according to the method by which the animals were herded into the corral (vehicles system: vehicles only; mixed system: people on foot and vehicles; and Chaku system: people on foot only). Attempts to escape, alarm calls, increased vigilance, vocalizations, and kicking were measured to quantify the stress response. A total of 478 vicunas were captured between May 2003 and November 2005. Vicunas captures by mixed system showed alert and active behaviours and vocalized more in the handling corral. The most active animals inside the corrals showed higher respiratory and heart frequency during handling (r = 0.44, P < 0.05 and r = 0.58, P < 0.001, respectively) and the heart rate increase was inversely proportional to blood glucose and creatin kinase (CK levels) (r = -0.31, P = 0.05 and r = -0.4, P = 0.05, respectively). Females captured by people on foot showed greater concentrations of cortisol (174 +/- 10.5 nmol/L), compared to vicunas captured by people and vehicles (127.38 +/- 12.5 nmol/L) (F((1,21)) = 7.22, P < 0.05). Cortisol levels peaked between 90 and 120 min post-capture (female = 177.13 +/- 7.67 nmol/L: male = 135.11 +/- 13.23 nmol/l.). CK (In) increased significantly according to time spent in captivity. The system that caused the fewest stress responses in vicunas was capture by people on foot. (c) 2010 Elsevier B.V. All rights reserved.
Endocrine changes during pregnancy, parturition and post-partum in guanacos (Lama guanicoe)
(ELSEVIER SCIENCE BV, 2009) Luis Riveros, Jose; Urquieta, Bessie; Bonacic, Cristian; Hoffmann, Bernd; Bas, Fernando; Schuler, Gerhard
Plasma concentrations of progesterone (P4), estradiol-17 beta (E2), estrone (E1) and estrone sulfate (E1S) were measured during gestation in eight guanacos kept in captivity. Gestational length was 346.1 +/- 9.8 days. P4 plasma concentrations increased after ovulation and remained elevated until parturition. However, during the last 4 weeks of gestation, a gradual decrease from 4.17 x 1.17(+/- 1) nmol/L to 2.02 x 1.95(+/- 1) nmol/L on day 5 before parturition was observed, followed by a more abrupt final decline to baseline concentrations which were reached on the day after parturition. Mean E2 plasma concentrations started to increase during the eighth month of gestation, and were significantly elevated up to maximum concentrations of 484.7 x 1.21(+/- 1) pmol/L during the last 2 months of pregnancy. Concentrations returned to baseline during the last 2 days of gestation. An increase of E1S concentrations (p < 0.01) was observed in the eleventh month of gestation. Mean El S concentrations remained rather constant during the last 3 weeks of gestation between 4 to 8 nmol/L until parturition, when a steep precipitous decline was observed. E1 concentrations were slightly elevated during the last 4 weeks of gestation, however, maximum concentrations did not exceed 1.5 nmol/L The results show distinct species specific features of gestational steroid hormone profiles in the guanaco in comparison to domestic South American camelids, such as a more pronounced gradual prepartal decrease of P4 concentrations prior to the final decline to baseline, and clearly lesser EIS concentrations during the last 4 weeks of gestation, which lack a continuous prepartal increase. (C) 2009 Elsevier B.V. All rights reserved.
Invasive American mink Mustela vison in wetlands of the Cape Horn Biosphere Reserve, southern Chile: what are they eating?
(CAMBRIDGE UNIV PRESS, 2009) Ibarra Eliessetch, José Tomás; Fasola, Laura; Macdonald, David W.; Rozzi, Ricardo; Bonacic, Cristian
The impact of alien American mink on the native fauna of oceanic islands has been demonstrated in a number of locations. In the sub-Antarctic Cape Horn Biosphere Reserve of southern Chile the species is currently expanding in an area where the native fauna evolved in the absence of terrestrial predators. To evaluate any emerging problems we therefore investigated seasonal variation in prey use by mink on Navarino Island within the Reserve. We identified undigested remains in 414 scats collected from the shores of 27 ponds over January-November 2006. Diet consisted mainly of mammals and birds. Mammals, including both native and exotic rodents, were the predominant prey in all seasons but birds were of equal importance during the summer (when birds breed and their abundance and diversity increases on the island). Exotic rodents were the only identifiable mammalian prey item during winter. Native wetland birds constituted a substantial proportion of mink diet, and greater than that reported in other areas. Many birds breeding on Navarino Island are ground-nesting, a strategy that evolved in the absence of native mammalian predators. Considering the international importance of this region, our results emphasize the need for an assessment of the impact of mink predation on the populations of native prey.
Molecular genetic evidence for social group disruption of wild vicunas Vicugna vicugna captured for wool harvest in Chile
(ELSEVIER, 2009) Sarno, Ronald J.; Gonzalez, Benito A.; Bonacic, Cristian; Zapata, Beatriz; O'Brien, Stephen J.; Johnson, Warren E.
Since 1994 wild vicunas have been captured and shorn for their wool, yet, there remains a noticeable lack of data regarding the possible influence of capture and shearing upon vicuna biology. Therefore, we assessed post-capture group composition, genetic relatedness, and paternity among animals that were captured for live shearing and release. We captured twenty-six groups (134 animals) on the Chilean Altiplano. Seventy-three percent of Male Groups (designated prior to chase) contained exclusively adult males upon capture,whereas remaining "Male Groups" contained crias and/or adult females and crias. Forty-seven percent of Family Groups (designated prior to chase) contained I adult male, adult females, and the number of crias <= the number of adult females. Remaining Family Groups contained no or multiple adult males, and more crias than adult females. Average relatedness among all vicunas was -0.007. Paternity analysis revealed that 35% of crias were captured with their biological mother and that only 1 cria was captured with both biological parents. Based on previous observations of group composition in the wild, animals from different groups may separate and/or mix during the chasing stage. Improvement of the chasing technique and instituting a post-capture monitoring program may aid in the detection of medium- and long-term impacts regarding group stability, cria survival, and ultimately wool production. (C) 2009 Elsevier B.V. All rights reserved.
Ovarian follicular dynamics and hormonal secretory profiles in guanacos (Lama guanicoe)
(ELSEVIER SCIENCE BV, 2010) Luis Riveros, Jose; Schuler, Gerhard; Bonacic, Cristian; Hoffmann, Bernd; Graciela Chaves, M.; Urquieta, Bessie
The objective of the present study was to describe ovarian activity in 11 adult non-mated guanacos, evaluated every second day for 40 days by transrectal ultrasonography and by plasma estradiol-17 beta and progesterone concentrations. An inverse relationship (r = -0.29, P < 0.001) was observed between the diameter of the largest ovarian follicle and the total number of follicles indicating that follicular growth in guanacos occurs in waves. The mean duration of follicular wave was 15.1 +/- 4.2 days with a range from 9 to 26. The follicular growth phase was 7.0 +/- 2.4 days, the static phase 3.0 +/- 1.2 days, the regression phase 5.2 +/- 2.1 days and the inter-wave interval was 12.6 +/- 5.6 days. The maximum follicular diameter in each follicular wave was 10.2 +/- 2.1 mm with a range from 7.2 to 16.1 mm. Inter-wave intervals of longer duration were associated with a larger maximum follicle diameter (P<0.001). Follicular activity alternated between ovaries in 93% of the waves with 48% of dominant follicles occurring in the left and 52% in the right ovary without differences (P>0.05). Plasma estradiol-17 beta concentrations showed a wave-like pattern, varying from 20.0 to 92.1 pmol/L. Plasma progesterone concentrations remained below 1 nmol/L without any ultrasonic evidence of ovulation during the study. These results in guanacos suggest a follicular wave pattern more similar to the llama (Lama glama) than previously described in other South American and Old World camelid species. (C) 2009 Published by Elsevier B.V.
Ravines as conservation strongholds for small wildcats under pressure from free-ranging dogs and cats in Mediterranean landscapes of Chile
(TAYLOR & FRANCIS LTD, 2021) Beltrami, Esperanza; Galvez, Nicolas; Osorio, Christian; Kelly, Marcella J.; Morales Moraga, David; Bonacic, Cristian
The Chilean Mediterranean ecosystem is threatened by anthropogenic pressures, such as habitat loss by intensive agriculture and urban sprawl. Abandoned dogs (Canis lupus familiaris) and cats (Felis silvestris catus) pose conservation challenges for Chilean wildlife including the pampas cat (Leopardus colocolo) and the guina (Leopardus guigna). We used camera trap data to investigate influences of natural and anthropogenic landscape features on spatiotemporal trends of these species. We also used co-occurrence modeling and kernel density estimation to investigate spatial and temporal patterns overlap of wildcats, free-ranging (FR) dogs, and FR-cats. FR-dogs showed the highest detection and site use probabilities, while guinas had the lowest across 80 camera trap sites. Top models showed no spatial avoidance between species and co-occurrence of wildcats was positively influenced by forest habitat. However, FR-dogs negatively affected detection of wildcats. Ravines surrounded by forest positively influenced guina and pampas cat detection probabilities when dominant species were not present. FR-dogs and wildcats had significantly different temporal activity patterns and low overlap coefficients, while wildcats and FR-cats showed high overlap in activity patterns. We suggest changing current policies to control domestic animals and strategic planning in agricultural areas of central Chile to better conserve native wildcat species.
Response of mesocarnivores to anthropogenic landscape intensification: activity patterns and guild temporal interactions
(OXFORD UNIV PRESS INC, 2021) Galvez, Nicolas; Meniconi, Paola; Infante, Jose; Bonacic, Cristian
Carnivores face important anthropogenic threats in agricultural areas from habitat loss and fragmentation, disturbance by domestic free-roaming dogs and cats, and direct hunting by humans. Anthropogenic disturbances are shifting the activity patterns of wild animals, likely modifying species interactions. We estimated changes in the activity patterns of the mesocarnivore guild of agricultural landscapes of the La Araucania region in southern Chile in response to land-use intensification, comparing intra- and interspecific activity patterns at low and high levels of forest cover, fragmentation, and land ownership subdivision. Our focal species comprise the guina or kod-kod (Leopardus guigna), two fox species (Lycalopex culpaeus and L. griseus), a skunk (Conepatus chinga), and one native mustelid (Galictis cuja), in addition to free-roaming dogs (Canis lupus familiaris) and cats (Felis catus) and their main mammalian prey species (i.e., Rodentia and Lagomorpha). In 23,373 trap nights, we totaled 21,729 independent records of our focal species. Our results show tendencies toward nocturnality at high land-use intensification, with potential impacts on species fitness. Nocturnal mesocarnivores decreased their diurnal/crepuscular activity, while cathemeral activity shifted to nocturnal activity at high land-use intensification, but only when in sympatry with a competitor. High land-use intensification decreased the activity overlap between native and domestic mesocarnivores but increased the overlap between native mesocarnivores. High intensification also reduced overlap with prey species. Notably, foxes displayed peaks of activity opposing those of dogs, and plasticity in activity pattern when in sympatry with dogs, such as strategies to avoid encounters. We stress the need to suppress the free-roaming and unsupervised activity of dogs to mitigate impacts of high land-use intensification on mesocarnivores.
Rufous-legged Owl (Strix rufipes) and Austral Pygmy Owl (Glaucidium nanum) stand use in a gradient of disrupted and old growth Andean temperate forests, Chile
(TAYLOR & FRANCIS LTD, 2012) Ibarra Eliessetch, José Tomás; Galvez, Nicolas; Gimona, Alessandro; Altamirano, Tomas A.; Rojas, Isabel; Hester, Alison; Laker, Jerry; Bonacic, Cristian
We studied how human induced structural changes in forests affect stand use of the Rufous-legged Owl (forest-specialist) and the Austral Pygmy Owl (forest-facultative), in a gradient from lowland disrupted forests to protected Andean forests in Chile. We also tested if the calls of one species influenced the calling behaviour of the other. We detected a total of 34 Rufous-legged Owls and 21 Austral Pygmy Owls during the four seasons. Rufous-legged Owls were found principally in old growth Araucaria-Nothofagus stands (32.4%), and Pygmy Owls in old growth evergreen stands (52.4%). For both species there was a seasonal effect on call response, with a drop in responses in autumn and winter. Our models suggested that Rufous-legged Owls inhabit a more specific range of habitat characteristics than Pygmy Owls. The former selected stands with tall trees, relatively low tree density, and high bamboo density. Pygmy Owls selected stands with tall trees and relatively high tree density. There was no evidence that either species influenced the calling behaviour of the other, suggesting no negative association between use of a territory by the two species. Our results emphasize the importance of structural components of old growth forests for both species, but also the relevance of stands surrounding protected areas.
Species richness, diversity and human activities in an elevation gradient of a high-ecosystem in Lagunas Huascoaltinas, Atacama Region, Chile.
(2009) Sanhueza, Doris; Miranda, Marcelo; Gómez, Miguel; Bonacic, Cristian
Tree-cavity survival for biodiversity in temperate forests of South America: A multi-scale approach
(Elsevier B.V., 2023) Paratori Girardi, Mariangela Antonieta; Novoa, Fernando J.; Altamirano, Tomás A.; Ibarra Eliessetch, José Tomás; Bonacic, Cristian
© 2023 Elsevier B.V.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.

Browsing by Author "Bonacic, Cristian"

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