Browsing by Autor "Ximena Velez–Liendo"

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A new occurrence record for the Vulnerable Rhinella rumbolli&nbsp;(Carrizo, 1992) (Anura, Bufonidae) in Tarija, Bolivia
(Pensoft Publishers, 2021) Patricia Mendoza-Miranda; Beatriz Nieto‐Ariza; Marisol Hidalgo-Cossio; Ximena Velez–Liendo
We present a new altitudinal record for Salta Toad, Rhinella rumbolli (Carrizo, 1992). This species is recorded in northern Argentina and southern Bolivia from 700 to 1800 m a.s.l. Our new record comes from San Lorencito, M&eacute;ndez Province, Tarija Department, Bolivia, and extends the altitudinal range by 569 m a.s.l.
Contribution of camera-trapping to the knowledge of Abrocoma boliviensis
(Asociacion Mexicana de Mastozoología A.C., 2020) Carmen Julia Quiroga Pacheco; Marisol Hidalgo-Cossio; Ximena Velez–Liendo
Rare and endemic rodent species, such as the critically endangered Bolivian chinchilla rat, Abrocoma boliviensis, are infrequently captured using traditional trapping methods. Therefore, to determine their presence and abundance, indirect records (bird pellets, feces, bone remains) are often used. Although not a popular method for rodents, the incorporation of photography is known to provide precise data. Therefore, the objective of this report was to demonstrate the importance of using photographic records and occupancy models in the study of the distribution and ecology of a small-body species with high conservation value. We used photographic records obtained from 180 camera-trap nights in two areas of the Andean dry forests of Bolivia, during both wet and dry seasons. Data analysis include the estimates of presence probability of A. boliviensis in the study sites, using an exploratory occupancy analysis. The estimated presence probability of Abrocoma boliviensis for the study sites were 30.2 % during dry season and 33.9 % during wet season. However, due to the limited amount of photographic records for the species , it was not possible to accurately determine the factors affecting the species presence probability. Camera-trapping records and associated metadata provided new ecological and distribution data for the Bolivian chinchilla rat. In combination with information about threats that the species faces, our data may be useful in generating and applying conservation actions.
Distribution, ecology, and conservation of Xenarthra in Bolivia — update to 2021
(2021) Enzo Aliaga‐Rossel; Carmen J. Quiroga; Ximena Velez–Liendo; Alfredo Romero‐Muñoz; Zulia Porcel; Robert B. Wallace; Guido Ayala; María Viscarra; Erika Cuéllar Soto; Teresa Tarifa
We present an update on the taxonomy, distribution, ecology, threats, and conservation status of Bolivian Xenarthra (orders Cingulata and Pilosa) based on articles published between 2010 and 2021. The Andean hairy armadillo Chaetophractus nationi has been synonymized with the less threatened C. vellero sus. Cabassous squamicaudis has been revalidated for Bolivia. Dasypus kappleri has been divided into three species; D. beniensis is the species present in Bolivia. Cyclopes didactylus was divided into seven species; C. catellus is the species in Bolivia. Chlamyphorus was divided into two genera; Calyptophractus retusus is the species in Bolivia. Recent camera trap and biodiversity surveys extend records of Xenarthra into the dry forests of the central and southern Andes of Bolivia. No comprehensive population assessment or basic ecological studies were undertaken for any Xenarthra species in the country during the period. However, indirectly, armadillos and anteaters have been included in recent studies using camera traps to evaluate effects of forest management, forest fragmentation, agriculture, and hunting on terrestrial mammals. Deforestation is the major threat to Xenarthra, exacerbated by economic pressures, policy changes, and frequent extensive fires in the past decade. The majority of xenarthrans are affected by hunting for subsistence consumption, meat sales, and/or cultural purposes. Overall, the conservation status of Xenarthra species in Bolivia is thought to be relatively stable, with vast protected areas, indigenous territories, and certified forestry concessions where deforestation and hunting are limited. However, outside of protected areas, threats are increasing. Direct research on Bolivian Xenarthra is needed, especially studies on longterm population trends, habitat preferences, and distribution in less-studied and threatened ecosystems such as the Chiquitano Dry Forest and the Bolivian-Tucumn Forest.
Effects of Seasonality on the Large and Medium-Sized Mammal Community in Mountain Dry Forests
(Multidisciplinary Digital Publishing Institute, 2024) Carmen Julia Quiroga-Pacheco; Ximena Velez–Liendo; Andreas Zedrosser
Seasonality drives natural processes, impacting environmental factors like temperature and resource availability, leading to shifts in wildlife communities. The Andean dry forests exhibit a marked seasonality, with a dry and cold season (May–September) and a warm, wet season (October–April). In a year-long remote camera survey in Southern Bolivia, we identified 29 medium to large mammal species, 18 outside their known distribution ranges. While overall species richness remained stable, photographic records varied between seasons. Capture rates, reflecting species richness and abundance, were more influenced by season and habitat. Wet season rates were lower, but higher in all other habitats compared to the mountain bush and grasslands. Rates increased with altitude and distance to hiking trails, but decreased with increasing distance from main roads. Medium to large mammals were more active during the dry season, indicating adjustments in response to seasonal changes. Our results suggest a cumulative impact of various factors beyond mere seasonality, and call for adjustments in global species distributions. Moreover, emphasize the need for biodiversity monitoring in dry forest habitats, particularly regarding responses to environmental shifts and human-induced alterations.
Effects of variable selection on modelling habitat and potential distribution of the Andean bear in Bolivia
(2013) Ximena Velez–Liendo; Diederik Strubbe; Erik Matthysen
Species distribution models are used in ecology and conservation biology to draw inferences about the drivers of species' ranges. However, poor conceptual background, environmental variable selection, and algorithm selection can contribute to misleading model predictions. We assessed the effects of environment variable selection and compared statistical performance and output maps of correlative resource- and biotope-based models for estimating the habitat and potential distribution of the Andean bear (Tremarctos ornatus) in Bolivia's Tropical Andes. The resource-based approach estimated bear habitat using 7 resources associated with 3 ecological functions: feeding, shelter, and access to water. In contrast, the biotope model described the habitat by applying 11 environmental predictors related to topography, vegetation, and human activities. Both models performed equally well overall and better than random, with shelter as the most influential variable for the resource model and Yunga forest for the biotope model. However, discrepancies in the extent and arrangement of predicted bear distribution between models differed and emphasized the effect of variable selection, which could influence the delineation of conservation areas for this species. We suggest using a resource-based approach when modelling species distribution because of the more direct relationship to the species investigated and greater ease of interpreting results.
Human visual identification of individual Andean bears <i>Tremarctos ornatus</i>
(BioOne, 2014) R Horn; Rebecca Zug; Corrin LaCombe; Ximena Velez–Liendo; Susanna Paisley
It is often challenging to use invasive methods of individual animal identification for population estimation, demographic analyses, and other ecological and behavioral analyses focused on individual‐level processes. Recent improvements in camera traps make it possible to collect many photographic samples yet most investigators either leap from photographic sampling to assignment of individual identity without considering identification errors, or else to avoid those errors they develop computerized methods that produce accurate data with the unintended cost of excluding participation by local citizens. To assess human ability to visually identify Andean bears Tremarctos ornatus from their pelage markings we used surveys and experimental testing of 381 observers viewing photographs of 70 Andean bears of known identity. Neither observer experience nor confidence predicted their initial success rate at identifying individuals. However, after gaining experience observers were able to achieve an average success at identifying adult bears of 73.2%, and brief simple training further improved the ability of observers such that 24.8% of them achieved 100% success. Interestingly, observers who were initially more likely to falsely identify two photos of the same bear as two different bears than vice versa were likely to continue making errors and their bias became stronger, not weaker. Such biases would lead to inaccurate population estimates, invalid assessments of the bears involved in conflict situations, and underestimates of bear movements. We thus illustrate that in some systems accurate data on individual identity can be generated without the use of computerized algorithms, allowing for community engagement and citizen science. In addition, we show that when using observers to collect data on animal identity it is important to consider not only the overall frequency of observer error, but also observer biases and error types, which are rarely reported in field studies.
Landscape assessment of habitat suitability and connectivity for Andean bears in the Bolivian Tropical Andes
(2014) Ximena Velez–Liendo; Frank Adriaensen; Erik Matthysen
The survival of large and mobile species in the face of habitat loss and fragmentation depends on several factors, including the landscape configuration of subpopulations and the dispersal capabilities of the species. We performed a landscape analysis of the Bolivian Tropical Andes to determine whether remaining habitat patches were suitable in terms of ecological characteristics and potential connectivity for the long-term survival of the Andean bear (Tremarctos ornatus). First we built a ruled-based model to identify key patches or areas large enough to sustain a viable population by using knowledge of Andean bear habitat requirements and movement patterns. Second, we estimated potential functional connectivity among these areas applying a cost-distance analysis based on estimates of the resistance to movement through the landscape. Finally, we quantified the proportion of these key patches and corridor habitats within the Bolivian protected area system. The rule-based model identified 13 key patches covering 21,113 km2 corresponding to a maximum estimated population of 3,165 adult bears. Using cost-distance analysis, all 13 key patches were potentially connected to ≥1 other key patch. Twelve of the patches were at least partially protected by national parks, and 40% of areas considered suitable as corridors were included within a protected area. Although the current protected area system includes suitable bear habitat, large portions of key patches and corridors are unprotected, which could eventually lead to fragmentation and habitat loss if these areas are not protected.
New distribution records of eighteen mammalian species (Artiodactyla, Cervidae, Tayassuidae; Carnivora, Canidae, Felidae, Procyonidae, Ursidae; Cingulata, Dasypodidae; Didelphimorphia, Didelphidae; Lagomorpha, Leporidae; Pilosa, Myrmecophagidae; Primates, Atelidae; Rodentia, Dasyproctidae, Abrocomidae) in Bolivia&rsquo;s neglected inter-Andean dry forests: implications for their global conservation status
(Pensoft Publishers, 2026) Ximena Velez–Liendo; Paul Bamford; Carmen Julia Quiroga-Pacheco
We report new distribution records for 18 mammal species in Tarija, Bolivia. Tremarctos ornatus (Cuvier, 1825), Puma concolor (Linnaeus, 1771), Cerdocyon thous (Linnaeus, 1766), Lycalopex gymnocercus (Fischer, 1814), Leopardus wiedii (Schinz, 1821), Herpailurus yagouaroundi (Geoffroy Saint-Hilaire, 1803), Nasua nasua (Linnaeus, 1766), Procyon cancrivorus (Cuvier, 1798), Mazama americana (Erxleben, 1777), Mazama gouazoubira (Fischer, 1814), Pecari tajacu (Linnaeus, 1758), Euphractus sexcinctus (Linnaeus, 1758), Didelphis albiventris (Wagner, 1842), Sylvilagus brasiliensis (Linnaeus, 1758), Tamandua tetradactyla (Linnaeus, 1758), Alouatta caraya (Humboldt, 1812), Dasyprocta puncata (Gray, 1842), and Abrocoma boliviensis (Glanz & Anderson, 1990).
Patrones de distribución y zoogeografía de los murciélagos de Bolivia
(European Organization for Nuclear Research, 2003) Luís F. Aguirre; Ximena Velez–Liendo; Arturo Muñoz; Angela Selaya
(Uploaded by Plazi for the Bat Literature Project) No abstract provided.
Photos provide information on age, but not kinship, of Andean bear
(2015) R Horn; Rebecca Zug; Robyn D. Appleton; Ximena Velez–Liendo; Susanna Paisley; Corrin LaCombe
Using photos of captive Andean bears of known age and pedigree, and photos of wild Andean bear cubs < 6 months old, we evaluated the degree to which visual information may be used to estimate bears’ ages and assess their kinship. We demonstrate that the ages of Andean bear cubs ≤ 6 months old may be estimated from their size relative to their mothers with an average error of < 0.01 ± 13.2 days (SD; n = 14), and that ages of adults ≥ 10 years old may be estimated from the proportion of their nose that is pink with an average error of < 0.01 ± 3.5 years (n = 41). We also show that similarity among the bears’ natural markings, as perceived by humans, is not associated with pedigree kinship among the bears (R 2 < 0.001, N = 1,043, p = 0.499). Thus, researchers may use photos of wild Andean bears to estimate the ages of young cubs and older adults, but not to infer their kinship. Given that camera trap photos are one of the most readily available sources of information on large cryptic mammals, we suggest that similar methods be tested for use in other poorly understood species.
Photos provide information on age, but not kinship, of Andean bear
(PeerJ, Inc., 2015) R Horn; Rebecca Zug; Robyn D. Appleton; Ximena Velez–Liendo; Susanna Paisley; Corrin LaCombe
Using photos of captive Andean bears of known age and pedigree, and photos of wild Andean bear cubs <6 months old, we evaluated the degree to which visual information may be used to estimate bears' ages and assess their kinship. We demonstrate that the ages of Andean bear cubs ≤6 months old may be estimated from their size relative to their mothers with an average error of <0.01 ± 13.2 days (SD; n = 14), and that ages of adults ≥10 years old may be estimated from the proportion of their nose that is pink with an average error of <0.01 ± 3.5 years (n = 41). We also show that similarity among the bears' natural markings, as perceived by humans, is not associated with pedigree kinship among the bears (R (2) < 0.001, N = 1,043, p = 0.499). Thus, researchers may use photos of wild Andean bears to estimate the ages of young cubs and older adults, but not to infer their kinship. Given that camera trap photos are one of the most readily available sources of information on large cryptic mammals, we suggest that similar methods be tested for use in other poorly understood species.
Photos provide information on age, but not kinship, of Andean bear
(2015) R Horn; Rebecca Zug; Robyn D. Appleton; Ximena Velez–Liendo; Susanna Paisley; Corrin LaCombe
Using photos of captive Andean bears of known age and pedigree, and photos of wild Andean bear cubs < 6 months old, we evaluated the degree to which visual information may be used to estimate bears’ ages and assess their kinship. We demonstrate that the ages of Andean bear cubs ≤ 6 months old may be estimated from their size relative to their mothers with an average error of < 0.01 ± 13.2 days (SD; n = 14), and that ages of adults ≥ 10 years old may be estimated from the proportion of their nose that is pink with an average error of < 0.01 ± 3.5 years (n = 41). We also show that similarity among the bears’ natural markings, as perceived by humans, is not associated with pedigree kinship among the bears (R 2 < 0.001, N = 1,043, p = 0.499). Thus, researchers may use photos of wild Andean bears to estimate the ages of young cubs and older adults, but not to infer their kinship. Given that camera trap photos are one of the most readily available sources of information on large cryptic mammals, we suggest that similar methods be tested for use in other poorly understood species.
Population genetics and lineage structure of the endangered Bolivian chinchilla rat Abrocoma boliviensis
(2025) Daniela Arenas-Viveros; Teresa Tarifa; Marisol Hidalgo-Cossio; Omar F. Osco; Ximena Velez–Liendo; Jorge Salazar‐Bravo
<title>Abstract</title> Studies on conservation genetics of endangered species have the ability to identify which populations should be the focus of management plans. The Bolivian chinchilla rat, <italic>Abrocoma boliviensis</italic>, is currently threatened by its rarity, paucity of information about its natural history, and landscape transformation driven by anthropogenic activities. Given the conservation status and limited distribution of <italic>A. boliviensis</italic>, understanding how its genetic diversity is apportioned is crucial to inform any potential conservation efforts. In this study, we assessed the genetic diversity and population structure of <italic>A. boliviensis</italic> as a first approximation to a comprehensive evaluation of the species. Mitochondrial data from 11 individuals of <italic>A. boliviensis</italic> reveal high levels of genetic distance, nucleotide diversity and polymorphisms, all of which indicate the existence of three separate clades. This is further supported by reduced representation genomic data that shows little to no admixture between these clades, suggesting that these lineages have been on separate evolutionary pathways and should be identified, at minimum, as separate evolutionary significant units. Our contribution highlights the urgency with which survey efforts must become the first order of action, and how new population-level data will provide a better understanding of the species, the evolutionary trajectory of its lineages, and the steps to take towards its conservation.
Scale dependence in multitemporal mapping of forest fragmentation in Bolivia: implications for explaining temporal trends in landscape ecology and applications to biodiversity conservation
(Elsevier BV, 2003) Andrew Millington; Ximena Velez–Liendo; Andrew V. Bradley