Browsing by Author "Martin, Kathy"

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    Árboles viejos y muertos en pie: un recurso vital para la fauna del bosque templado de Chile
    (2012) Altamirano Oyarzún, Tomás Alberto; Ibarra Eliessetch, José Tomás; Martin, Kathy; Bonacic Salas, Cristián
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    Avian diversity above the clouds: comparing elevational patterns in north and south temperate mountains
    (2018) Altamirano Oyarzún, Tomás Alberto; De Zwaan, Devin; Ibarra Eliessetch, José Tomás; Martin, Kathy
    Mountain ecosystems comprise 24% of the land-base of the Americas, and are critical components of the life-cycle for 35% of North American bird species. Globally, however, high elevation avian communities are poorly monitored, with taxonomic and functional diversity receiving little attention. In 2017, we initiated a temperate montane bird study, comparing: i) taxonomic and functional turnover across three habitats increasing in elevation: upper montane (>50% tree cover), subalpine (5-50% tree cover), and alpine (<5% tree cover), and ii) the breeding strategies of alpine birds in North and South America. We conducted 600 diurnal bird point counts in six North temperate (British Columbia, Canada; 54°N latitude) and 10 South temperate mountains (Chile; 39°S latitude). Species richness was comparable between sites (49-54 species), but decreased with elevation in Canada (upper montane: 31, alpine: 16) compared to remaining consistent across elevation in the Chilean Andes (~33 in each habitat). Species composition among mountains was highly variable in both hemispheres (Jaccard index < 0.5) indicating potential variation in drivers such as habitat structure. We found contrasting patterns in alpine breeding strategies, as open-cup nesters made up 88% (14/16 species) of the Canadian alpine community, while 100% of the 37 nests (6 species) found in the Chilean alpine were cavity nesters (rock crevices or ground excavations). Comparing high elevation temperate ecosystems in the Americas provides a strong framework to address avian breeding dynamics in stochastic environments, as well as understand the potential conservation value of mountain habitats as refugia for avian populations with environmental change
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    Changing lenses to understand and manage forest biodiversity: nest webs as Complex Adaptive Systems in the Americas
    (2017) Ibarra Eliessetch, José Tomás; Altamirano Oyarzún, Tomás Alberto; Cockle, Kristina L.; Van der Hoek, Yntze; Simard, Suzanne; Bonacic Salas, Cristián; Martin, Kathy
    A single dominant objective (e.g. flagship or threatened species) usually shapes the "lenses" through which biodiversity is assessed and managed in forest ecosystems. However, forests are Complex Adaptive Systems (CAS) in which patterns at higher levels emerge from localized networks of many entities (species, guilds) interacting at lower levels. Tree cavity-nesting communities exist within interaction networks known as "nest webs" that link trees, excavators (e.g. woodpeckers), and secondary cavity nesters (e.g. many songbirds, ducks, raptors, and other vertebrates). Despite growing acknowledgement of the importance of using Complex System Science (CSS) by conservation biologists, its application for understanding nest webs is just emerging. We assess the properties of nest webs (heterogeneity, hierarchy, memory, adaptation, and non-linearity) as CAS using situated exemplars from cavity-nesting communities across temperate, subtropical , and tropical forests of the Americas (Chile, Canada, Argentina, Ecuador). Although our nest webs have independent evolutionary histories, structures, and disturbance patterns, they share the main properties of CAS. We show that applying CSS in this context has implications for the usage of new, but also conventional conservation management concepts and practices. Understanding nest webs as CAS will facilitate our ability to view how forest-dwelling cavity nesters self-organize and adapt in the face of rapid changes occurring in forests of the Americas.
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    Combining point counts and autonomous recording units improves avian survey efficacy across elevational gradients on two continents
    (WILEY, 2021) Drake, Anna; de Zwaan, Devin R.; Altamirano, Tomas A.; Wilson, Scott; Hick, Kristina; Bravo, Camila; Ibarra Eliessetch, José Tomás; Martin, Kathy
    Accurate biodiversity and population monitoring is a requirement for effective conservation decision making. Survey method bias is therefore a concern, particularly when research programs face logistical and cost limitations. We employed point counts (PCs) and autonomous recording units (ARUs) to survey avian biodiversity within comparable, high elevation, temperate mountain habitats at opposite ends of the Americas: nine mountains in British Columbia (BC), Canada, and 10 in southern Chile. We compared detected species richness against multiyear species inventories and examined method-specific detection probability by family. By incorporating time costs, we assessed the performance and efficiency of single versus combined methods. Species accumulation curves indicate ARUs can capture ~93% of species present in BC but only ~58% in Chile, despite Chilean mountain communities being less diverse. The avian community, rather than landscape composition, appears to drive this dramatic difference. Chilean communities contain less-vocal species, which ARUs missed. Further, 6/13 families in BC were better detected by ARUs, while 11/11 families in Chile were better detected by PCs. Where survey conditions differentially impacted method performance, PCs mostly varied over the morning and with canopy cover in BC, while ARUs mostly varied seasonally in Chile. Within a single year of monitoring, neither method alone was predicted to capture the full avian community, with the exception of ARUs in the alpine and subalpine of BC. PCs contributed little to detected diversity in BC, but including this method resulted in negligible increases in total time costs. Combining PCs with ARUs in Chile significantly increased species detections, again, for little cost.Combined methods were among the most efficient and accurate approaches to capturing diversity. We recommend conducting point counts, while ARUs are being deployed and retrieved in order to capture additional diversity with minimal additional effort and to flag methodological biases using a comparative framework
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    Complex dynamics of tree cavities and nest webs in the Americas
    (2018) Cockle, Kristina; Ibarra Eliessetch, José Tomás; Trzcinski, Kurtis; Wiebe, Karen L.; Altamirano Oyarzún, Tomás Alberto; Edworthy, Amanda; Martin, Kathy
    The Nest Web concept represents tree-cavity-nesting communities as hierarchical, commensal networks, whereby nesting cavities flow upward from trees to cavity producers (e.g., woodpeckers, decay organisms) to a diverse assemblage of non-excavators (e.g., parrots, songbirds). These nest webs are dynamic, complex, and often resilient. They include non-hierarchical feedback loops, such as facultative excavation, inter-guild predation and competition. For >20 years we studied >4000 nesting cavities in temperate British Columbia, Canada (1995-2016), temperate Chile (2010-2018) and subtropical Argentina (2006-2018), to examine the dynamics of cavity-nesting communities over time, at scales from individual cavities to whole nest webs. Individual cavities in large old-growth trees persisted longest. Cavities became larger as they aged, and were occupied by a succession of vertebrates (excavators, then small-bodied non-excavators, and finally largebodied non-excavators). Cavities produced 0–43 fledglings/cavity over their lifetime, but cavities with higher nest success were occupied fewer times by fewer species. At the nest web scale in Canada, an abundant facultative excavator declined in importance in the Nest Web during an insect outbreak that attracted obligate excavators, but then dramatically increased cavity production following wildfires. Logging resulted in disproportional biodiversity losses when it targeted key network hubs (large trees; Chile, Argentina) but not when a critical nesting tree species was retained (Canada). A nest web approach helped us understand interspecific interactions and test network theory; because these networks are strongly influenced by outside sources of uncertainty and non-linearity, a Complex Systems Science approach may improve predictions about their long-term dynamics
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    Correction to: The conservation value of tree decay processes as a key driver structuring tree cavity nest webs in South American temperate rainforests (vol 26, pg 2453, 2017)
    (SPRINGER, 2018) Altamirano Oyarzún, Tomás Alberto; Ibarra Eliessetch, José Tomás; Martin, Kathy; Bonacic Salas, Cristian
    In the original publication of the article, Table 3 was incorrectly published. The corrected Table 3 is given below.
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    Estacionalidad y selección de hábitat del comesebo grande (Pygarrhichas albogularis) en el bosque templado andino de La Araucanía, Chile
    (2013) Vermehren, Alejandra; Ibarra Eliessetch, José Tomás; Altamirano, Tomás A.; Martin, Kathy; Bonacic Salas, Cristian
    Los bosques templado y mediterráneo de Sudamérica están aislados por más de 1.000 km de otros bosques y presentan un alto porcentaje de endemismos y especies relictas del Cenozoico. El comesebo grande (Pygarrhichas albogularis) es un especie relicta y monogenérica de estos bosques, pero relativamente desconocida. Entre 2008-2013 estudiamos su estacionalidad y selección de hábitat en 505 sitios en un gradiente altitudinal entre 300 y 1.400 m de altitud en la región de La Araucanía, Chile. Mediante puntos de conteo y la cuantificación de elementos estructurales del hábitat registramos que P. albogularis no presentó estacionalidad en sus abundancias relativas, a pesar de las condiciones ambientales extremas en invierno, lo que podría asociarse a sus hábitos de forrajeo y una disponibilidad estable de alimento durante el año. El bosque antiguo de altura, dominado por Araucaria araucana y Nothofagus pumilio, registró las mayores abundancias de P. albogularis. La clase de descomposición de los árboles (desviación estándar) y cobertura de dosel superior (%) fueron las variables que mejor predijeron la abundancia relativa de P. albogularis, con una relación positiva para ambos atributos. Nuestros resultados sugieren que bosques en estados sucesionales avanzados y con mayor variabilidad en las clases de descomposición de árboles, serían mayormente seleccionados debido a que proveen sustratos de alimentación y para la excavación de cavidades para su reproducción. Enfatizamos la necesidad de mantener árboles viejos y muertos en pie en planes de manejo forestal dada la importancia de éstos para poblaciones residentes de P. albogularis en el bosque templado
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    Factors Associated with the Detectability of Owls in South American Temperate Forests: Implications for Nocturnal Raptor Monitoring
    (2014) Martin, Kathy; Altamirano Oyarzún, Tomás Alberto; Vargas, F. Hernán; Bonacic Salas, Cristián
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    Fire regimes shape biodiversity: responses of avian guilds to burned forests in Andean temperate ecosystems of southern Chile
    (RESILIENCE ALLIANCE, 2021) Novoa Galaz, Fernando Javier; Altamirano Oyarzún, Tomás Alberto; Bonacic Salas, Cristian; Martin, Kathy; Ibarra Eliessetch, José Tomás
    Fire regimes of forests, i.e., time interval, frequency, extent, and severity of fire events, influence structural changes in the vegetation, and thus shape the composition of avian communities. We studied the diversity of avian guilds in sites with different fire regimes (unburned, burned 2002, burned 2015, and burned 2002 and 2015), testing both the "intermediate disturbance" and "vertical vegetation structure" hypotheses, in globally threatened temperate forests in Chile. From 2016 to 2018, we quantified habitat attributes (160 plots) and estimated avian richness and density (160 point counts). The site that was burned once in 2015 showed the highest density of standing dead trees at 96.5% higher than the unburned/control site, whereas the site that burned twice showed the lowest density of live trees, lowest average diameter at breast height of trees (DBH), and smallest volume of coarse woody debris. Overall, we recorded 35 avian species with the highest richness (n = 24 species) in the site that was burned once in 2002. We found that, 16 years after a site was burned, the avian community composition became relatively similar to the unburned site. The density of most avian guilds decreased in burned sites but granivores, shrub users, and migrants showed positive responses. Understory users, foliage users, and resident species showed negative responses to burned sites. These responses were strongly related to fire-driven changes in habitat attributes, supporting both of our tested hypotheses. Given that increasing levels of disturbance from fire are anticipated, future management of temperate forest biodiversity should consider that specific species and guilds will depend on remnant habitat attributes in burned sites.
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    Habitat-specialist owls, but not generalists, are reliable surrogates for taxonomic and functional diversity in Andean temperate forests
    (2015) Ibarra Eliessetch, José Tomás; Martin, Kathy
    Conservation practices commonly focus on measures of species diversity that merelyinclude information on species richness (i.e., taxonomic diversity). However, functionaldiversity (range, distribution and density of trait values of species in a community) should be more informative than taxonomic diversity as it measures those aspects of diversity thataffect ecosystem function. Previous work in the northern hemisphere has shown that owlsmay act as surrogates for taxonomic diversity but little is known on their value assurrogates of functional diversity. We assessed the surrogacy reliability of two sympatricowls, Strix rufipes (habitat-specialist) and Glaucidium nana (habitat-generalist), in Andeantemperate forests of southern Chile. During 2011-2013, we conducted 1,145 owl surveys,505 avian point-transects and 505 vegetation surveys across 101 sites comprising a range ofconditions from degraded habitat to structurally complex old-growth forest stands. Wefound that only Strix rufipes was a reliable surrogate for both taxonomic and functionaldiversity measures, including the density of vulnerable avian guilds (e.g., bamboounderstory users and large-tree users) and the degree of habitat-specialization of the aviancommunity. We found that forest-stand structural complexity (sites with dense understoryand availability of large trees) was the underlying mechanism driving the positive relation between forest-specialist owls and biodiversity. Our results show a tight association between habitat-specialist owls and avian functional traits that may be more informativethan species richness to prioritize the conservation of stable, functioning ecosystems
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    Maintaining ecosystem resilience: functional responses of tree cavity nesters to logging in temperate forests of the Americas
    (2017) Ibarra Eliessetch, José Tomás; Martin, Michaela; Cockle, Kristina L.; Martin, Kathy
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    ¿No hay búhos en este sitio, o no los detectamos?: factores que influencian la detectabilidad de rapaces nocturnas en el bosque templado sudamericano
    (2013) Ibarra Eliessetch, José Tomás; Martin, Kathy; Altamirano, Tomás A.; Vargas, F. Hernán; Vermehren, Alejandra; Bonacic Salas, Cristian
    Los búhos son crípticos, de hábitos principalmente nocturnos y se encuentran en densidades bajas. Estudios sobre su ecología son susceptibles de incurrir en "falsos-ausentes" (i.e. no detección en sitios que en realidad sí están ocupados) y obtener estimadores sesgados de sus distribuciones y abundancias. Entre 2011 y 2013 evaluamos factores temporales, ambientales y biológicos que influencian las probabilidades de detección de Strix rufipes y Glaucidium nana en 101 sitios del bosque templado andino de Chile. Realizamos 1.145 muestreos mediante señuelos acústicos durante siete meses (dos temporadas reproductivas), obteniendo 292 detecciones para Strix y 334 para Glaucidium. Modelos de ocupación dinámicos para poblaciones abiertas indicaron probabilidades iniciales de 0,63 de ocupación y de 0,43 de detección para Strix, y de 0,78 y 0,36 para Glaucidium. Los mejores modelos indicaron que la probabilidad de detección de Strix es función de la luminosidad lunar (efecto positivo), ruido ambiental (negativo) y la detección de Glaucidium en el mismo sitio (positivo). Por su parte, la detectabilidad de Glaucidium fue función de la detección de Strix en el mismo sitio (efecto positivo), luminosidad lunar (positivo), ruido ambiental (negativo) y del período de muestreo en la temporada (mayores registros al final de estación reproductiva). La baja detectabilidad (<0,5) de ambas especies sugiere la necesidad de corregir el sesgo de detección en muestreos y programas de monitoreo, con el fin de asignar eficientemente los recursos (humanos y económicos) y obtener estimadores confiables sobre la distribución, abundancia y uso de hábitat de rapaces nocturnas del bosque templado sudamericano
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    Occurrence patterns and niche relationships of sympatric owls in South American temperate forests: A multi-scale approach
    (ELSEVIER SCIENCE BV, 2014) Ibarra Eliessetch, José Tomás; Martin, Kathy; Drever, Mark C.; Vergara, Gonzalo
    Habitat-specialists have narrower niches, but achieve higher or similar peak performance (e.g. occurrence probability, psi) than habitat-generalists along resource gradients that may be selected from the stand- to landscape-levels. Understanding the relationship between niche width and psi of forest owls will facilitate the development of appropriate management recommendations for their conservation. We assessed psi of the threatened habitat-specialist rufous-legged owls (Strix rufipes) and habitat-generalist austral pygmy-owls (Glaucidium nana) across three spatial scales, and tested whether they differed in resource utilization and peak psi in temperate forests of southern Chile. We conducted 1145 broadcast surveys at 101 sites and used multi-season occupancy models, accounting for imperfect detection, to estimate psi. For S. rufipes, psi ranged between 0.05 and 1 across sites, and was positively associated with the variability (standard deviation, SD) in diameter at breast height (DBH) of trees and bamboo understory density. For G. nana, psi ranged between 0.67 and 0.98, and was positively associated with forest-patch shape index (irregularity and edge effects) and forest cover at 180 ha, although the parameter estimates were imprecise. Relative to G. nana, S. rufipes had lower total resource utilization due to lower psi over gradients of all covariates, but achieved similar peak psi for resources related with stand-level forest complexity and forest stability at the landscape scale. Occurrence of habitat-specialist owls will be promoted if multi-aged stands with a variety of tree sizes (SD of DBH = 19.9 +/- 9 cm), including large old-growth trees, with relatively high bamboo cover (34.2 +/- 26.6%), are retained. Landscapes with forest cover >63.5% would also favor occurrence by habitat-specialist owls. (C) 2014 Elsevier B.V. All rights reserved.
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    Redes de nidificación: composición y estructura de la comunidad nidificadora de cavidades del bosque templado sudamericano
    (2013) Altamirano Oyarzún, Tomás Alberto; Ibarra Eliessetch, José Tomás; Martin, Kathy; Bonacic Salas, Cristián
    Las aves nidificadoras de cavidades (ANC) interactúan dentro de “redes de nidificación”, ordenándose jerárquicamente en gremios reproductivos, donde la composición y estructura de la red es influenciada por la disponibilidad de cavidades y por interacciones inter e intra específicas. Durante tres temporadas reproductivas (2010-2013), examinamos los componentes y estructura de la comunidad de ANC en el bosque templado de Chile, mediante la búsqueda y monitoreo de nidos (hasta 15 m de altura), y cuantificación del hábitat. Las ANC (n=29), considerando tanto especies obligadas como facultativas de cavidades, son el mayor componente de la comunidad de aves del bosque templado (55% de las especies). La mayoría (n=25), son nidificadoras de cavidades secundarias y cuatro son primarias (excavadoras). Encontramos 251 nidos de 20 especies, incluyendo una especie no previamente descrita como NC y tres mamíferos. El 72% de los nidos se encontró en cavidades formadas por procesos naturales (fisuras, madera descompuesta y quiebres de ramas), y el 28% restante en cavidades excavadas (principalmente por Pygarrhichas albogularis). Árboles muertos en pie y ramas muertas fueron el sustrato más común de nidificación. A pesar de la baja riqueza de especies en la comunidad estudiada, la diversidad funcional de ésta es comparable con otras comunidades de ANC que poseen dos o tres veces más especies. Para determinar la disponibilidad real de sitios reproductivos y el impacto del manejo forestal sobre esta comunidad, es necesario explorar la selección especie-específica y la calidad de estos sitios, junto con la fuerza y dirección de las relaciones inter-específicas (competencia/facilitación/depredación).
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    Seasonal dynamics of avian guilds inside and outside core protected areas in an Andean Biosphere Reserve of southern Chile
    (2017) Ibarra Eliessetch, José Tomás; Gálvez Robinson, Nicolás Cristián; Altamirano Oyarzún, Tomás Alberto; Caviedes, Julián; Rojas, Isabel M.; Bonacic Salas, Cristián; Martin, Kathy
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    The conservation value of mountain habitats for birds in the Americas and predicted impacts of climate change
    (2018) Ibarra Eliessetch, José Tomás; Martin, Kathy
    High mountain habitats are experiencing globally significant increases in temperature, extreme weather and climate-induced habitat loss, but predicting impacts to birds is hampered by the limited information regarding avian use of temperate mountain areas in the Americas. We used point count methods, across elevations to examine taxonomic and functional diversity in temperate mountains in North and South America. In North America, species richness was highest in upper montane habitat and lowest in the alpine with significant inter-mountain variation in species diversity. In contrast, there was comparable richness in the montane, sub-alpine and alpine habitats of the temperate Andes. During fall migration in British Columbia, we detected 95 species in 30 families using high mountain habitats. One quarter of these species are on conservation concern lists. In total, we found that ~35% of North America's breeding bird species use mountains for at least three months annually, a period equivalent to the length of the breeding season. Regarding climate variation, alpine songbirds cope well with daily mountain weather events, while multi-day colder storms lead to reduced nesting success. Climate models predict that suitable habitat for alpine birds in the coastal mountains will decrease by 50-75% by 2080 due to climate-induced changes, further reducing connectivity across already fragmented mountain habitats. Overall we found that avian use of mountain areas is extensive, and many species are of conservation concern. Our results emphasize the need for effective conservation of high mountain habitats that are increasingly threatened by local, regional and global anthropogenic disturbance.
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    The conservation value of tree decay processes as a key driver structuring cavity nest webs in South American temperate rainforests
    (2017) Altamirano Oyarzún, Tomás Alberto; Ibarra Eliessetch, José Tomás; Martin, Kathy; Bonacic Salas, Cristián
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    The conservation value of tree decay processes as a key driver structuring tree cavity nest webs in South American temperate rainforests
    (2018) Altamirano, Tomas A.; Tomas Ibarra, Jose; Martin, Kathy; Bonacic Salas, Cristian