Conference Presentations by Kathy Martin
27th International Ornithological Congress, Vancouver, Canada, 2018
High mountain habitats are experiencing globally significant increases in temperature, extreme we... more 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.
A single dominant objective (e.g. flagship or threatened species) usually shapes the " lenses " t... more 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.
Conservation practices commonly focus on measures of species diversity that merely include inform... more Conservation practices commonly focus on measures of species diversity that merely include information on species richness (i.e., taxonomic diversity). However, functional diversity (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 that affect ecosystem function. Previous work in the northern hemisphere has shown that owls may act as surrogates for taxonomic diversity but little is known on their value as surrogates of functional diversity. We assessed the surrogacy reliability of two sympatric owls, Strix rufipes (habitat-specialist) and Glaucidium nana (habitat-generalist), in Andean temperate 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 of conditions from degraded habitat to structurally complex old-growth forest stands. We found that only Strix rufipes was a reliable surrogate for both taxonomic and functional diversity measures, including the density of vulnerable avian guilds (e.g., bamboo understory users and large-tree users) and the degree of habitat-specialization of the avian community. We found that forest-stand structural complexity (sites with dense understory and 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 informative than species richness to prioritize the conservation of stable, functioning ecosystems.
Papers by Kathy Martin
Journal of Ornithology, 1994
Among birds, many studies have shown that the reproductive performance of individuals increases w... more Among birds, many studies have shown that the reproductive performance of individuals increases with advancing age (1); effects of senescence have been demonstrated less frequently. To date, most work has dwelled principally on the evolution and maintenance of ontogenetic processes (2). Relatively little attention has been focused on the underlying ecological, physiological and social mechanisms responsible for the widespread pattern of age-specific reproduction in birds. With behaviour and energetics studies, and monitoring success of known-age individuals throughout their lives one can begin elucidating some of the mechanisms involved. Biological mechanisms may act directly on age classes to influence fitness of individuals, or indirectly by interactions with ecological or environmental factors. When age-specific variation occurs at an early life history stage (e. g., spring body condition), age-specific effects may cascade through the breeding effort and profoundly influence an individuai's fitness. Little is known about factors responsible for senescence. In this symposium, 5 types of biological mechanisms are examined. Foraging ability and/or efficiency and physiological efficiency (converting nutrients to eggs or energetic cost of parental duties) may improve with age, resulting in improved breeding success. The ability to acquire high quality nest sites may also improve with age and/or experience (2). Young birds may perform poorly because they are less able to compete with older neighbours (social dominance) for high quality nesting or foraging sites. Parental competence, such as &fenc e of young may improve with age, perhaps because older parents are more knowledgeable in choosing good brood rearing sites, more vigilant for predators, or more competent at defending offspring from predators. Within species, age-specific effects may occur at some life history stages and be absent in others (2, 3). The pattern or strength of age-specific effects for a trait like clutch size, may vary with habitat type, environmental extreme (3) or landscape degradation. Thus, biological mechanisms that cause age-specific performance may explain a substantial amount of the variation in reproductive success of birds observed annually or among populations. Future work should develop general relationships such as whether age-specific patterns are related to life history patterns such as foraging mode, longevity or taxon. Several studies have shown that age-specific effects involve both proximate and ultimate factors (2, 4). Experiments need to be done across age classes that discriminate between proximate (constraint) and ultimate (restraint) mechanisms.
Mountains produce distinct environmental gradients that may constrain or facilitate both the pres... more Mountains produce distinct environmental gradients that may constrain or facilitate both the presence of avian species and/or specific combinations of functional traits. We addressed species richness and functional diversity to understand the relative importance of habitat structure and elevation in shaping avian diversity patterns in the south temperate Andes, Chile. During 2010-2018, we conducted 2,202 point-counts in four mountain habitats (successional montane forest, old-growth montane forest, subalpine, and alpine) from 211 to 1,768 m in elevation and assembled trait data associated with resource use for each species to estimate species richness and functional diversity and turnover. We detected 74 species. Alpine specialists included 16 species (22%) occurring only above treeline with a mean elevational range of 298 m, while bird communities below treeline (78%) occupied a mean elevational range of 1,081 m. Treeline was an inflection line, above which species composition chan...
Biodiversity and Conservation, 2019
Cavity-nesting animals and their nest trees are linked in interspecific facilitation networks kno... more Cavity-nesting animals and their nest trees are linked in interspecific facilitation networks known as nest webs, which play key roles in forest function but vary across biomes and with human perturbation. We examined the composition, structure and function of nest webs between two endangered old-growth forests representing the last remnants of the ancient coniferous family Araucariaceae in South America: pewen (Araucaria araucana; Endangered) in temperate Chile (2010-2018), and Parana pine (Araucaria angustifolia; Critically Endangered) in subtropical Argentina (2006-2018). Pewen and Parana pine accounted for 30 and 9% of forest basal area, but only 2 and 5% of nesting cavities, respectively. Instead, cavity-nesting birds and mammals nested disproportionately in coexisting broadleaf trees. Species richness, interaction richness, and mean number of links per species were much higher in Parana pine forest than in pewen forest, but the two nest webs had similar levels of evenness and nestedness. Most secondary cavity-nesting species depended on cavities formed by decay in Nothofagus spp. (98% of nest cavities in pewen forest) or Apuleia leiocarpa (26% of nest cavities in Parana pine forest). An exception was the globally endangered Vinaceous Parrot, a Parana pine seed disperser, which made 50% of its nests in decay-formed cavities in Parana pine. To conserve the ecosystem functions of endangered Araucaria forests it is important to protect and recruit not only Araucaria trees but also a mix of broadleaf trees that can confer resilience to nest webs in the face of major disturbances. Keywords Cavity-nesting birds • Ecological network • Interspecific interactions • Neotropics • Nest web • Old-growth forest Communicated by Karen E. Hodges. This article belongs to the Topical Collection: Forest and plantation biodiversity.
Avian Conservation and Ecology, 2007
As an "Easter diversion" while enrolled in Chemistry at the University of Edinburgh, Jamie Smith ... more As an "Easter diversion" while enrolled in Chemistry at the University of Edinburgh, Jamie Smith accompanied his friend John Shanks to Ailsa Craig in the Firth of Clyde to count North Atlantic Gannets. This trip precipitated his switch to the study of Zoology and a lifelong interest in the ecology of bird populations, especially on islands. James Neil Munro Smith, known to most as "Jamie," was born on 1 May 1944 in Rothesay on the Isle of Bute, Scotland, and lived much of his early life with his grandparents while his parents were in Nigeria. Jamie graduated from Edinburgh in 1967 as a Zoologist, and completed a D.Phil. under Mike Cullen at Oxford (1967-1971). As a Smithsonian Research Fellow, he studied population variation on Darwin's Finches in the Galapagos with Peter and Rosemary Grant, before moving to Canada to assume a faculty position in the Zoology Department at the University of British Columbia (UBC) in 1973. For the next three decades, Jamie combined his love of birds, science, nature, and wild places to make major and sustained contributions to ornithological science, conservation, and education in Canada. He lost an 11-year battle to cancer on 18 July 2005 at his home in Vancouver,
Ecology and Behavior of Chickadees and Titmice, 2007
Journal of Ecosystems and Management
Outbreaks of mountain pine beetle are evaluated as a generic disturbance agent, and comparisons a... more Outbreaks of mountain pine beetle are evaluated as a generic disturbance agent, and comparisons are made with other forest disturbances such as wildfire, windthrow, and logging. A useful basis for comparison is the degree of disruption to the overstorey, understorey, and forest floor layers. Clear differences are observed in the impacts of bark beetles, fire, and windthrow, but there is overlap with various harvesting systems. Insects are selective in terms of the species or size of tree that is killed; this selectivity varies with stand composition, stand structure, and outbreak stage. The mountain pine beetle functions as part of larger natural disturbance regimes in western North America, which vary with climate and forest type. Outbreaks of many different insects occur throughout western Canada, with the relative role of fire and insects differing among ecoregions and over time. Beetle-killed stands may facilitate extreme fire behaviour and may be more susceptible to future burn...
Functional Ecology, 2019
1. Variation in offspring development is expected to be driven by constraints on resource allocat... more 1. Variation in offspring development is expected to be driven by constraints on resource allocation between growth and maintenance (e.g., thermoregulation). Rapid post-natal development decreases predation risk to offspring, while inclement weather likely prolongs development. For taxa with parental care, parental behaviour may partially buffer offspring against extrinsic drivers like predation risk and severe weather. 2. Using a 7-year dataset from an alpine population of horned lark Eremophila alpestris, a ground-nesting songbird in northern British Columbia, Canada, we investigated multiple potential drivers of variation in the duration of incubation and nestling development. 3. Using path analysis, we evaluated the direct effects of weather, predation risk, and parental care on offspring development, as well as, indirect developmental 'carry-over' effects of conditions during incubation on the nestling period. 4. Nestling period duration varied by nearly 100% (7-13 days) and incubation duration by 40% (10-14 days). Cold ambient temperatures late in the nestling period prolonged development by 1 day for every 2 days below 10°C; particularly when combined with heavy precipitation. Rapid nestling development was associated with high predation risk, and prolonging development incurred a nest survival cost (-2.3%/day). Females in good condition created nest environments that promoted rapid nestling development periods (average = 8-9 days) compared to poor condition females during harsh, early-season conditions (10-11 days), indicating parental buffering capabilities against environmental constraints. Fledging age was weakly correlated with incubation duration (r =-0.21) suggesting minimal developmental carry-over effects. 5. Given high nest predation risk, immediate fitness benefits can be derived by overcoming environmental constraints and reducing development time. While predation risk was influential, inclement weather and maternal condition had stronger effects on variation in offspring development. Addressing multiple drivers of variation in key life-history traits can Accepted Article This article is protected by copyright. All rights reserved. provide important context for understanding life-history theory under changing environmental conditions.
Wildlife 2001: Populations, 1992
Snowshoe hares (Lepus americanus) and their predators fluctuate cyclically in abundance every 9–1... more Snowshoe hares (Lepus americanus) and their predators fluctuate cyclically in abundance every 9–11 years in the southwestern Yukon. Peak populations occurred in 1980–1981 and in 1989–90 around Kluane Lake. During the first cycle (1977–84) we tested food limitation hypotheses by providing three hare populations with supplemental food (rabbit chow). Extra food did not prevent the cyclic decline, and neither the timing nor the rate of the decline from 1981-84 was affected by food addition, in comparison with controls. During the second cycle (1986-present) we have been testing the predator hypothesis, and are trying to find out if there is an interaction between predators and food. We have constructed two mammalian predator exclosures (1 km2) and on one of these areas we are adding food. We have fertilized two large areas with nitrogenphosphorus-potassium fertilizer to increase plant production, and we have added hare food to two unfenced areas as well. Within the next 4 years we should be able to evaluate the effects of these manipulations on the snowshoe hare cycle.
Animal Behaviour, 1992
Willow ptarmigan, Lagopus lagopus, usually pair monogamously, but a small proportion of males are... more Willow ptarmigan, Lagopus lagopus, usually pair monogamously, but a small proportion of males are polygynous. During the pre-incubation period males accompany their mates and provide vigilance while females feed. Polygyny may be uncommon because of costs to females that share male vigilance. Time-activity budgets, reproductive success and survival of experimentally polygynous (hens that became polygynous when males were removed) and monogamous females were compared. Monogamous hens were accompanied by their mates 94% of the time and polygynous hens 60% of the time. When polygynous hens were alone they had a tendency to forage less and be alert more than when they were accompanied by the male. Polygynous hens that had low male accompaniment spent less time foraging than monogamous or polygynous hens with higher male accompaniment. Polygynous hens were involved in more agonistic interactions with other hens than monogamous hens. However, polygynous hens did not have lower reproductive success or survival than monogamous hens. Our results were compared with two other experimental studies on willow ptarmigan: one on the same population at a higher breeding density and another on a different population at low density. We conclude that male investment may be important for female survival over the autumn and winter in some years, but monogamy may be prevalent because of constraints to males of obtaining more than one female.
Avian Conservation and Ecology, 2021
Fire regimes of forests, i.e., time interval, frequency, extent, and severity of fire events, inf... more 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. Le régime des incendies façonne la biodiversité : réactions des guildes aviaires aux forêts brûlées dans les écosystèmes andins tempérés du sud du Chili RESUME_. Le régime des incendies de forêt, c'est-à-dire l'intervalle de temps, la fréquence, l'étendue et la sévérité des incendies, influent sur les changements structurels de la végétation et donc sur la composition des communautés aviaires. Nous avons étudié la diversité des guildes aviaires dans des sites présentant différents régimes d'incendie (non brûlé, brûlé en 2002, brûlé en 2015, et brûlé en 2002 et 2015), en testant à la fois les hypothèses de « perturbation intermédiaire » et de « structure verticale de la végétation » dans des forêts tempérées du Chili menacées à l'échelle planétaire. De 2016 à 2018, nous avons mesuré les caractéristiques de l'habitat (160 parcelles) et calculé la richesse et la densité aviaire (160 dénombrements par points d'écoute). Le site qui a brûlé une fois en 2015 présentait la plus forte densité d'arbres morts sur pied, soit 96,5 % de plus que le site non brûlé/témoin, tandis que le site qui a brûlé deux fois présentait la plus faible densité d'arbres vivants, le plus faible diamètre moyen à hauteur de poitrine des arbres (DHP) et le plus petit volume de débris ligneux grossiers. Nous avons noté 35 espèces aviaires dans l'ensemble, et la plus grande richesse (n = 24 espèces) se trouvait dans le site qui a brûlé une fois en 2002. Nous avons constaté que, 16 ans après qu'un site ait brûlé, la composition de la communauté aviaire était redevenue relativement similaire à celle du site non brûlé. La densité de la plupart des guildes aviaires a diminué dans les sites brûlés, mais les granivores, les utilisateurs d'arbustes et les migrateurs ont eu des réactions positives. Les utilisateurs du sous-étage, les utilisateurs du feuillage et les espèces résidentes ont réagi négativement aux sites brûlés. Ces réactions étaient fortement liées aux changements des attributs de l'habitat induits par le feu, résultat qui soutient nos deux hypothèses. Étant donné qu'on prévoit une augmentation des perturbations par le feu, la gestion future de la biodiversité des forêts tempérées devrait tenir compte du fait que des espèces et des guildes spécifiques dépendront des attributs de l'habitat restant dans les sites brûlés.
Ecology and Evolution, 2021
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Ambio, 2019
Rock ptarmigan (Lagopus muta) and willow ptarmigan (L. lagopus) are Arctic birds with a circumpol... more Rock ptarmigan (Lagopus muta) and willow ptarmigan (L. lagopus) are Arctic birds with a circumpolar distribution but there is limited knowledge about their status and trends across their circumpolar distribution. Here, we compiled information from 90 ptarmigan study sites from 7 Arctic countries, where almost half of the sites are still monitored. Rock ptarmigan showed an overall negative trend on Iceland and Greenland, while Svalbard and Newfoundland had positive trends, and no significant trends in Alaska. For willow ptarmigan, there was a negative trend in mid-Sweden and eastern Russia, while northern Fennoscandia, North America and Newfoundland had no significant trends. Both species displayed some periods with population cycles (short 3-6 years and long 9-12 years), but cyclicity changed through time for both species. We propose that simple, cost-efficient systematic surveys that capture the main feature of ptarmigan population dynamics can form the basis for citizen science efforts in order to fill knowledge gaps for the many regions that lack systematic ptarmigan monitoring programs.
Biodiversity and Conservation, 2017
South American temperate rainforests, a global biodiversity hotspot, have been reduced to nearly ... more South American temperate rainforests, a global biodiversity hotspot, have been reduced to nearly 30% of their original extent and most remaining stands are being degraded. Cavity-nesting vertebrate communities are dependent on cavity-bearing trees and hierarchically structured within nest webs. Evaluating the actual degree of cavity dependence (obligate, non-obligate) and the preferred attributes of trees by cavity nesters is critical to design conservation strategies in areas undergoing habitat loss. During three breeding seasons (2010–2013), we studied the cavity-nesting bird community in temperate rainforests of Chile. We found the highest reported proportion of tree cavity nesters (n = 29 species; 57%) compared to non-cavity-using birds for any forest system. Four species were excavators and 25 were secondary cavity nesters (SCNs). Among SCNs, ten species were obligate and 15 were non-obligate cavity nesters. Seventy-five percent of nests of SCNs were located in cavities produced by tree decay processes and the remaining 25% were in cavities excavated mainly by Pygarrhichas albogularis and Campephilus magellanicus. Nest web structure had a low dominance and evenness, with most network interactions occurring between SCNs and large decaying trees. Tree diameter at breast height (DBH) was larger in nest-trees (57.3 cm) than in available trees (26.1 cm). Cavity nesters showed a strong preference for dead trees, both standing and fallen (58% of nests). Our results stress that retaining large decaying and standing dead trees (DBH > 57 cm), and large fallen trees, should be a priority for retention in forest management plans in this globally threatened ecosystem.
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Conference Presentations by Kathy Martin
Papers by Kathy Martin