|
Ton, R., and T. E. Martin. 2015. Metabolism correlates with variation in post-natal growth rate among songbirds at three latitudes . Functional Ecology doi: 10.1111/1365-2435.12548.
|
November 2015
|
|
|
Ton, R, and T. E. Martin. 2017. Proximate effects of temperature versus evolved intrinsic constraints for embryonic development times among temperate and tropical songbirds. Scientific Reports 7(1), 895.
|
April 2017
|
|
|
Mouton, J. C. and T. E. Martin. 2018. Fitness consequences of interspecific nesting associations among cavity nesting birds. American Naturalist 192: 389–396.
|
September 2018
|
|
|
Martin, T.E., E. Arriero, and A. Majewska. 2011. A trade-off between embroyonic development rate and immune function of avian offspring is revealed by considering embroyic temperature. Biol. Lett. 7:425-428.
|
June 2011
|
|
|
Martin, T. E., and J. L. Maron. 2012. Climate impacts on bird and plant communities from altered animal-plant interactions. Nature Climate Change 2: 195-200.
|
Abstract
|
February 2012
|
The contribution of climate change to declining populations of organisms remains a question of outstanding concern1-3. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food4-6. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snow-melt drainages (10 ha/drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on a plant-animal interaction can have forceful ramifying effects on plants, birds, and ecological interactions.
|
|
Martin, T. E., R. Ton, and J. C. Oteyza. 2018. Adaptive influence of extrinsic and intrinsic factors on variation of incubation periods among tropical and temperate passerines. Auk 135: 101-113.
|
January 2018
|
|
|
Martin, T. E., R. Ton, and A. Niklison. 2013. Intrinsic vs. extrinsic influences on life history expression: metabolism and parentally-induced temperature influences on embryo development rate. Ecology Letters 16: 738-745.
|
Abstract
|
April 2013
|
Intrinsic processes are assumed to underlie life history expression and trade-offs, but extrinsic inputs are theorized to shift trait expression and mask trade-offs within species. Here, we explore application of this theory across species. We do this based on parentally-induced embryo temperature as an extrinsic input, and mass-specific embryo metabolism as an intrinsic process, underlying embryonic development rate. We found that embryonic metabolism followed intrinsic allometry rules among 49 songbird species from temperate and tropical sites. Extrinsic inputs via parentally-induced temperatures explained the majority of variation in development rates and masked a relationship with metabolism; metabolism explained a minor proportion of the variation in development rates among species, and only after accounting for temperature effects. We discuss evidence that temperature further obscures the expected inter-specific trade-off between development rate and offspring quality. These results demonstrate the importance of considering extrinsic inputs to trait expression and trade-offs across species.
|
|
Martin, T. E., J. C. Oteyza, A. J. Boyce, P. Lloyd, and R. Ton. 2015. Adult mortality probability and nest predation rates explain parental effort in warming eggs with consequences for embryonic development time. American Naturalist 186: 223-236.
|
Abstract
|
August 2015
|
The time that embryos take to develop is thought to affect mortality in later life because of physiological trade-offs associated with development time. Yet, an unexplored alternative hypothesis suggests that mortality may be the cause rather than consequence of embryo development time in birds; adult and offspring mortality may exert selection on parental effort in warming eggs to thereby determine embryo development times. We examined these possibilities based on field studies of 64 songbird species on four continents. Structural equation modeling showed that an association of age-specific mortality and embryonic development time was best explained by mortality as a cause of average embryonic temperature. Influence of age-specific mortality on parental effort in warming eggs is a unique result that follows from life history theory and provides a causal mechanism for explaining variation in embryonic development time across diverse species.
|
|
Martin, T. E., J. C. Oteyza, A. E. Mitchell, A. L. Potticary, and P. Lloyd. 2015. Post-natal growth rates of diverse songbird species covary weakly with embryonic development rates and do not explain adult mortality probability. American Naturalist 185: 380-389.
|
March 2015
|
|
|
Martin, T. E., B. Tobalske, M. M. Riordan, S. Case, and K. P. Dial. 2018. Age and performance at fledging is a cause and consequence of juvenile mortality between life stages. Science Advances 4: eaar1988.
|
Abstract
|
June 2018
|
Should they stay or should they leave? That is a critical question facing young birds in a nest as they mature. The answer has ramifications for juvenile mortality, an important influence on demography and fitness, but differs among species and the reasons why are unclear. The probability of young being eaten increases with each day they remain in the nest. We show that species at greater risk leave the nest at a younger age with less developed wings that cause poorer flight performance and greater subsequent mortality. Experimentally delayed fledging verifies that older age and better developed wings reduce juvenile mortality. Fitness benefits of staying in the nest to reduce fledgling mortality are opposed by nest predation costs, and parents and offspring conflict on the optimal resolution. Ultimately, fledging age and associated offspring development balance mortality in and out of the nest in a compromise between parents and offspring.
|
|
Martin, T. E. 2015. Consequences of habitat change and resource selection specialization for population limitation in cavity-nesting birds. Journal of Applied Ecology 52: 475–485.
|
Abstract
|
April 2015
|
Summary.
1. Resource selection specialization may increase vulnerability of populations to environmental change. One environmental change that may negatively impact some populations is the broad decline of quaking aspen (Populus tremuloides), a preferred nest tree of cavity-nesting organisms who are commonly limited by nest-site availability. However, the long-term consequences of this habitat change for cavity-nesting bird populations are poorly studied.
2. I counted densities of woody plants and eight cavity-nesting bird species (six woodpeckers, Mountain Chickadee Poecile gambeli, House Wren Troglodytes aedon) over 29 years in 15 high elevation riparian drainages in Arizona, USA. I also studied nest tree use and specialization over time based on 4946 nests across species.
3. Aspen suffered a severe decline in availability over time, while understory woody plants and canopy canyon maple (Acer grandidentatum) also declined. The decline of understory plants resulted from increased elk (Cervus canadensis) browsing linked to declining snowfall, and the lack of tree recruitment caused the decline in canopy aspen and maple.
4. All six woodpecker species exhibited very high specialization (>95% of nests) on aspen for nesting, and densities of all species declined with aspen over time. Mountain Chickadees and House Wrens exhibited increasingly less specialization on aspen. Chickadees strongly increased in density over time, despite a relatively high specialization on aspen. Nest sites clearly were not limiting their population. House Wren densities declined modestly over time, but nest box addition experiments demonstrated that nest-site availability was not limiting their population. House Wren densities increased with understory vegetation recovery in elk exclosures compared with controls, demonstrating that the decline in understory vegetation on the broader landscape was the cause of their population decline. The increased densities in exclosures were facilitated by increased generalization in nest site use.
5. Synthesis and applications: Management should target species that specialize in resource selection on a declining resource, because these species are vulnerable to population problems. Species with greater resource selection generalization can reduce population impacts of environmental change. Resource generalization can allow a species, like the wren, to take advantage of a habitat refuge, such as provided by the elk exclosures. Yet, when habitat on the broader landscape is declining in quality, or higher quality refuges are lacking, then resource generalization cannot offset the broader negative changes, as demonstrated by the decline in wrens on the broader landscape. Ultimately, aspen is an important habitat for biodiversity, and land management programs need to protect and aid recovery of aspen habitats.
|
|
Ghalambor, C. K., S. I. Peluc, and T. E. Martin. 2013. Plasticity of parental care under the risk of predation: how much should parents reduce care? Biology Letters 9: 20130154.
|
Abstract
|
August 2013
|
Predation can be an important agent of natural selection resulting in divergent parental care behaviors, and can also favor behavioral plasticity. Parent birds often decrease the rate that they visit the nest to provision offspring when perceived risk is high. Yet, the plasticity of such responses may differ among species as a function of either their relative risk of predation, or the mean rate of provisioning. Here, we report parental provisioning responses to experimental increases in the perceived risk of predation. We tested responses of 10 species of birds in north temperate Arizona and subtropical Argentina that differed in their ambient risk of predation. All species decreased provisioning rates in response to the nest predator but not a control. However, provisioning rates decreased more in species that had greater ambient risk of predation on natural nests. Thus, extent of plasticity varied among species in accord with risk.
|
|
Auer, S. K., and T. E. Martin. 2013. Climate change has indirect effects on resource use and overlap among coexisting bird species with negative consequences for their reproductive success. Global Change Biology 19: 411-419.
|
January 2013
|
|
