
Luke L. PowellResearch Centre in Biodiversity and Genetic Resources | CIBIO · TROPIBIO
Luke L. Powell
Ph.D
About
62
Publications
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Introduction
I'm a Curie Research Fellow with the University of Glasgow. My work mostly focuses on conservation ecology of insectivorous birds in tropical rainforests, but more recently, I've become interested in bats and biodiversity Central African cacao using diet metabarcoding.
Additional affiliations
June 2009 - October 2011
October 2013 - present
October 2013 - present
Education
January 2009 - September 2013
September 2005 - May 2008
September 1999 - May 2003
Publications
Publications (62)
Amazonia now contains vast areas of secondary forest because of widespread regeneration following timber harvests, yet the value of secondary forest to wildlife remains poorly understood. Secondary forest becomes structurally similar to primary forest after abandonment, and therefore we predicted that avian movement across the interface of primary...
Background/Question/Methods
Every autumn, billions of migratory songbirds depart North America for the Neotropics, where they spend ~7 months wintering alongside ecologically similar year-round residents. In the Caribbean, the winter influx of migrants coincides with low arthropod abundances, and food shortages limit wintering songbird population...
Animals are subject to ecological traps when anthropogenic changes create habitat that appears suitable but when selected results in decreased fitness. The Rusty Blackbird (Euphagus carolinus) breeds in boreal wetlands and has declined by 85–95% over the last half century. We studied nest-site selection and daily nest-survival rate (DSR) of 43 Rust...
We calculated the home ranges and core areas of 13 adult Rusty Blackbirds (Euphagus carolinus) in Maine to determine (1) the area requirements of breeding adults, (2) whether area requirements of the sexes and of colonial and noncolonial individuals differ, and (3) the proportion of the home range and core area that would be protected by a buffer o...
Soils from 18 parrot collpas (‘clay licks’) in southeastern Peru averaged four times more available sodium than uneaten control soils. Collpa soils contained marginally more clay than control sites and clay content was uncorrelated with available sodium content. Parrots may select and ingest soils based on available sodium content.
Suelos de 18 col...
Birds time their life cycle events to favourable windows in environmental conditions. In tropical environments, where photoperiod variation is small, birds show high variability in the timing of life cycle stages, yet these species have been severely underrepresented in phenology research. Here, we investigated temporal patterns in bird life cycles...
Balancing biodiversity conservation and agricultural productivity is commonly regarded as a trade-off, but such analyses overlook ecosystem services that functional biodiverse communities provide in agroecosystems, and the possibility that win-win strategies may exist. We developed a dynamic mechanistic community model of the bird-insect food web a...
Sub-Saharan Africa produces most of the Earth’s cacao. Although pests cause losses of hundreds of millions annually, the role of cacao pest suppressors remains unknown. We used an exclusion experiment to prevent access of bats and birds to cacao trees and quantified how their absence affected arthropod communities, herbivory, and crop yield. Overal...
Agricultural intensification is leading to conversion of cocoa agroforestry towards monocultures across the tropics. In the context of cocoa agriculture, arthropods provide a range of ecosystem services and dis‐services. Arthropod pests (e.g., mirids and mealybugs) can cause major damage to crops, whilst pollinators and natural enemies (e.g., preda...
Equatorial Guinea in central Africa hosts rich biodiversity and a network of protected areas (PAs). However, infrastructure development has facilitated access to previously remote forests. This has likely increased poaching in PAs, thereby complicating efforts of agencies tasked with protecting threatened mammals. Reserva Natural de Río Campo (RNRC...
Abundance estimation methods that combine several types of data are becoming increasingly common because they yield more accurate and precise parameter estimates and predictions than are possible from a single data source. These beneficial effects result from increasing sample size (through data pooling) and complementarity between different data t...
Woodcreepers (Dendrocolaptinae) represent a remarkably uniform group of brownish birds that move by hitching up tree trunks as they forage for arthropod prey. Despite these superficial similarities, we were able to uniquely differentiate the niches of all 13 species north of Manaus by integrating morphological traits (e.g., mass and bill size) with...
The cover image is based on the Letter AVONET: morphological, ecological and geographical data for all birds by Tobias et al., https://doi.org/10.1111/ele.13898. The sword‐billed hummingbird (Ensifera ensifera) is exquisitely adapted to its trophic niche as an aerial pollinator of flowerings plants (angiosperms) in the high Andes. A new global data...
Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVON...
Identifying the composition of avian diets is a critical step in characterizing the roles of birds within ecosystems. However, because birds are a diverse taxonomic group with equally diverse dietary habits, gaining an accurate and thorough understanding of avian diet can be difficult. In addition to overcoming the inherent difficulties of studying...
Warming from climate change is expected to reduce body size of endotherms, but studies from temperate systems have produced equivocal results. Over four decades, we collected morphometric data on a nonmigratory understory bird community within Amazonian primary rainforest that is experiencing increasingly extreme climate. All 77 species showed low...
The use of mist nets is the most widespread technique to capture bats; however, no study has compared if the type of ground-level mist net used during sampling affects bat captures. We sampled bats using three different types of mist nets that varied in mesh (16, 18, and 20 mm) and denier/ply (45/1 and 75/2) sizes over 76 half-night surveys. We use...
Understanding interactive effects between anthropogenic disturbance and abiotic factors on species turnover can help to identify and prioritize conservation of potentially vulnerable tropical bird communities. We investigated the potential factors influencing avian understory community composition along with a recently constructed road across three...
We thank Kristen Rosamond, Julie Nguyen, and Molly Fava for their assistance sorting and identifying prey from Jamaican wet‐limestone forest stomach samples. Nathan Cooper helped with the Louisiana fieldwork. We thank the many other field assistants, too many to name individually here, who made this research possible. We thank the Williams Family,...
Understanding spatial and temporal movement patterns of migratory birds throughout the annual cycle can help identify potential population threats. The behavior and habitat use of birds during migration and stopover periods is particularly understudied in many species. In this study, we used high spatial resolution archival GPS tags to track Rusty...
Forests are being converted to agriculture throughout the Afrotropics, driving declines in sensitive rainforest taxa such as understorey birds. The ongoing expansion of cocoa agriculture, a common small‐scale farming commodity, has contributed to the loss of 80% rainforest cover in some African countries. African cocoa farms may provide habitat for...
The slow-paced life history of many Neotropical birds (e.g., high survival and low fecundity) is hypothesized to increase lifetime fitness through investments in self-maintenance over reproduction relative to their temperate counterparts. Molt is a key investment in self-maintenance and is readily shaped by environmental conditions. As such, variat...
en The size of the pectoral muscle is an important component of body condition in birds and has been linked to indices of fitness and migratory performance. Bauchinger et al. (2011. Journal of Ornithology 152: 507–514) developed, calibrated, and validated an aluminum “muscle meter” device that estimates the size of pectoral muscles noninvasively. T...
The arrangement of habitat features via historical or contemporary events can strongly influence genomic and demographic connectivity, and in turn affect levels of genetic diversity and resilience of populations to environmental perturbation. The rusty blackbird (Euphagus carolinus) is a forested wetland habitat specialist whose population size has...
Wood Warblers, an Afro-Palearctic migrant species, are declining steadily in Europe likely due to mortality outside their breeding grounds. However, little is known about their overwintering, and records about the sensitive life-cycle stage of moult in Africa are practically absent. To fill this gap, we report on moult of Wood Warblers captured ove...
Once exceptionally abundant, the Rusty Blackbird (Euphagus carolinus) has declined precipitously over at least the last century. The species breeds across the Boreal forest, where it is so thinly distributed across such remote areas that it is extremely challenging to monitor or research, hindering informed conservation. As such, we employed a targ...
The contribution of interspecific competition to structuring population and community dynamics remains controversial and poorly tested. Interspecific competition has long been thought to influence the structure of migrant–resident bird communities in winter, yet experimental evidence remains elusive. The arrival of billions of songbirds into Neotro...
Chromatic disorders may disrupt adaptive coloration and reduce animals' capacity to survive and produce young. These disorders have been documented widely for bats across the globe. However, most of these cases are concentrated in regions with well-studied faunal communities, such as Europe or North and South America, with little documentation of c...
The Arctic is entering a new ecological state, with alarming consequences for humanity. Animal-borne sensors offer a window into these changes. Although substantial animal tracking data from the Arctic and subarctic exist, most are difficult to discover and access. Here, we present the new Arctic Animal Movement Archive (AAMA), a growing collection...
Ecological “big data”
Human activities are rapidly altering the natural world. Nowhere is this more evident, perhaps, than in the Arctic, yet this region remains one of the most remote and difficult to study. Researchers have increasingly relied on animal tracking data in these regions to understand individual species' responses, but if we want to...
How are rainforest birds faring in the Anthropocene? We use bird captures spanning > 35 years from 55 sites within a vast area of intact Amazonian rainforest to reveal reduced abundance of terrestrial and near‐ground insectivores in the absence of deforestation, edge effects or other direct anthropogenic landscape change. Because undisturbed forest...
The Rusty Blackbird (Euphagus carolinus) is a widespread, uncommon migrant that has experienced heavy population declines over the last century. This species can spend over a quarter of their annual cycle on migration, so it is important to determine their habitat requirements during stopover events to inform effective conservation planning. We ass...
Rusty blackbirds (Euphagus carolinus), once common across their boreal breeding distribution, have undergone steep, range-wide population declines. Newfoundland is home to what has been described as one of just two known subspecies (E. c. nigrans) and hosts some of the highest known densities of the species across its extensive breeding range. To c...
Rapidly increasing urbanisation requires mitigation against associated losses of biodiversity and species abundance. In urban-breeding birds, altered food availability for nestlings is thought to reduce reproductive success compared to forest populations. To compensate for shortages of preferred foods, urban parents could increase their search effo...
To achieve greater understanding of the full annual cycles of birds, it is critical to describe the spatial nature of little-understood phases. One of the least understood aspects of avian annual cycles is the ecology of molt: the periodic replacement of feathers. While work on the spatial nature of molt in migratory passerines has increasingly fou...
Migratory birds spend most of their journeys at stopover sites where they rest and refuel. Many migrants are in steep decline, and understanding their behavior within and among migrations is crucial for developing effective conservation strategies across the full annual cycle. One of the most rapidly declining songbirds in North America is the Rust...
Wild Amazonian parrots likely consume soil to supplement sodium-deficient diets. However, it remains uncertain whether parrots can detect sodium at the concentrations found in mineral licks. During 3–8 day trials, we presented 20 captive Hispaniolan Amazon Parrots (Amazona ventralis) two foods with experimentally manipulated sodium concentrations....
In early 2016, we conducted bird surveys on the island of Bioko, Equatorial Guinea. We found numerous taxa at different elevations and abundance from those previously reported. We recorded five species new for Bioko (African Jacana Actophilornis africanus, Bat Hawk Macheiramphus alcinus, Western Marsh Harrier Circus aeruginosus, Ethiopian Swallow H...
Mainland Equatorial Guinea is undergoing rapid infrastructure development driven by the discovery of large oil reserves within the country’s maritime political boundaries. The country recently began implementing Horizonte 2020, a national development project that includes a vast highway network and creation of a new capital city. Road construction...
During surveys of mainland Equatorial Guinea and Bioko in November 2013 and December
2014, 246 bird species were recorded, including six that were new for the country (Wahlberg’s Eagle
Hieraaetus wahlbergi, Pel’s Fishing Owl Scotopelia peli, Lyre-tailed Honeyguide Melichneutes robustus,
Yellow-throated Leaflove Atimastillas flavicollis, Ethiopian S...
Avian diversity in fragmented Amazonian landscapes depends on a balance between extinction and colonization in cleared and disturbed areas. Regenerating forest facilitates bird dispersal within degraded Amazonian landscapes and may tip the balance in favor of persistence in habitat patches. Determining the response of Amazonian birds to fragmentati...
Primary tropical rain forests are being rapidly perforated with new edges via roads, logging, and pastures, and vast areas of secondary forest accumulate following abandonment of agricultural lands. To determine how insectivorous Amazonian understory birds respond to edges between primary rain forest and three age classes of secondary forest, we ra...
Insectivorous birds may adjust their foraging strategies to exploit changes in resource distributions. Arthropod prey strongly influence habitat-specific persistence of long-distance migrant passerines in their wintering areas, and arthropods are strongly affected by rainfall. However, the effect of drought on the dynamics of avian foraging ecology...
The Yellow-billed Cotinga (Carpodectes antoniae) is one of Central America’s rarest and most endangered species. A regional endemic to Panama and Costa Rica, between 250 and 999 individuals appear to now survive mainly within Pacific coastal mangroves and adjacent lowland forest within the Térraba-Sierpe National Wetlands and the Osa Peninsula of C...
As anthropogenic change continues to fragment terrestrial habitats, conservation biologists are increasingly concerned with how wild animals move through fragmented landscapes. Experimental translocations have recently gained popularity as a technique to determine landscape permeability by wild animals in fragmented landscapes. In experimental tran...
The Rusty Blackbird (Euphagus carolinus), an uncommon songbird often associated with northern coniferous wetlands, has experienced a precipitous population decline since at least the early 20th century. Here, we provide the first analysis of breeding-habitat occupancy at the wetland scale and make recommendations for streamlined monitoring. We mode...
Resumen. – Notas sobre la distribucón, historia natural, y conservación de la Cotinga de Piquiamarillo (Carpodectes antoniae). – Hicimos un estudio a lo largo de la costa sur del Pacífico de Costa Rica y el oeste de Panamá para evaluar la distribución actual de la Cotinga Piquiamarillo (Carpo-dectes antoniae), una especie de ave poco conocida, en p...
The Rusty Blackbird (Euphagus carolinus), a formerly common breeding species of boreal wetlands, has exhibited the most marked decline of any North American landbird. North American Breeding Bird Survey (BBS) trends in abundance are estimated to be ‒12.5%/yr. over the last 40 years, which is tantamount to a >95% cumulative decline. Trends in abunda...
Euphagus carolinus (Rusty Blackbird) has suffered a steep population decline over the past 40 years, yet we still understand little of the basic biology of the species, particularly its social organization. During the spring of 2007, we located a loose colony of Rusty Blackbirds breeding in Piscataquis County, ME. The core colony consisted of six n...
Recent evidence suggests that mercury exposure has negative effects on the health of songbirds, and species that forage in wetlands may be at a greater risk of bioaccumulation of mercury than are those of other habitats. We examined mercury concentrations in blood and feathers from the wetland obligate and rapidly declining Rusty Blackbird (Euphagu...
We calculated the home ranges and core areas of 13 adult Rusty Blackbirds (Euphagus carolinus) in Maine to determine (1) the area requirements of breeding adults, (2) whether area requirements of the sexes and of colonial and noncolonial individuals differ, and (3) the proportion of the home range and core area that would be protected by a buffer o...
The Rusty Blackbird (Euphagus carolinus) is a poorly understood wetland-breeding songbird that has experienced an 85–95% population decline since the mid 20th century. Although anecdotal evidence suggests that Rusty Blackbirds are “loosely colonial” and breed in bogs, fens, beaver-modified wetlands, and wooded swamps of the boreal forest. Ornitholo...