No abstract

1. Ecosystem engineers modify biophysical environments, create novel habitats, and change biodiversity, with the ultimate effect of modulating critical ecosystem functions. This review describes and synthesises approaches, methodologies, and analytical frameworks for quantifying how ecosystem engineers drive ecosystem functioning.2. We i) outline what variables to measure, how to measure them, and define the appropriate ecological and spatiotemporal scales for monitoring changes in both ecosystem engineers and ecosystem functioning; ii) illustrate experiments involving species exclusion or removal, addition or re-introduction, and comparative designs when experimental manipulation is not feasible; and iii) describe statistical, datadriven, and theory-driven approaches for estimating and forecasting the impact of ecosystem engineers on ecosystem functioning.3. In the Anthropocene, humans are a salient example of an ecosystem engineer. We discuss how to leverage the ecosystem engineer knowledge in the context of current anthropogenic change for achieving conservation, restoration, and climatemitigation goals.4. We suggest evidence-based models and practises that can facilitate transformative changes in socio-ecological processes associated with ecosystem engineers. We conclude that implementing programs that monitor, forecast and apply the ecosystem engineer framework would sustain biological diversity and functional ecosystems.

For many territorial hummingbirds, habitat use is influenced primarily by the interaction between resource acquisition and non-foraging behaviors such as territory advertisement and defense. Previous research has highlighted the importance of foraging-associated habitat features like resource density and distribution in determining the space-use patterns of hummingbirds. Less is known, however, about how habitat selection associated with non-foraging behaviors influences space use by territorial species. We used radio telemetry to examine patterns of territorial space use by Shining Sunbeams (Aglaeactis cupripennis) in high Andean montane forests near Manu National Park, Peru, and Bosque Comunal "El Carmen" near Chordeleg, Ecuador. We quantified within-territory habitat characteristics related to resource acquisition and non-foraging behaviors such as territory advertisement and defense. We found that Shining Sunbeams showed high use of core areas in territories where foraging effort was relatively low. We found no relationship, however, between the position of core areas and habitat characteristics associated with territory defense, predator avoidance, or other non-foraging behaviors. We also found no relationship between use of non-core areas and habitat use based on resource acquisition. Thus, patterns of territorial space use by Shining Sunbeams may be characterized by core areas not determined by foraging behavior. Further studies examining territorial behaviors and the influence of intrusion pressure will help identify the underlying determinants of territory space use by this and other species of Andean hummingbirds.

Globally, zoonotic vector-borne diseases are on the rise and understanding their complex transmission cycles is pertinent to mitigating disease risk. In North America, Lyme disease is the most commonly reported vector-borne disease and is caused by transmission of Borrelia burgdorferi sensu lato (s.l.) from Ixodes spp. ticks to a diverse group of vertebrate hosts. Small mammal reservoir hosts are primarily responsible for maintenance of B. burgdorferi s.l. across the United States. Nevertheless, birds can also be parasitized by ticks and are capable of infection with B. burgdorferi s.l. but their role in B. burgdorferi s.l. transmission dynamics is understudied. Birds could be important in both the maintenance and spread of B. burgdorferi s.l. and ticks because of their high mobility and shared habitat with important mammalian reservoir hosts. This study aims to better understand the role of avian hosts in tick-borne zoonotic disease transmission cycles in the western United States. We surveyed birds, mammals, and ticks at nine sites in northern California for B. burgdorferi s.l. infection and collected data on other metrics of host community composition such as abundance and diversity of birds, small mammals, lizards, predators, and ticks. We found 22.8% of birds infected with B. burgdorferi s.l. and that the likelihood of avian B. burgdorferi s.l. infection was significantly associated with local host community composition and pathogen prevalence in California. Additionally, we found an average tick burden of 0.22 ticks per bird across all species. Predator and lizard abundances were significant predictors of avian tick infestation. These results indicate that birds are relevant hosts in the local B. burgdorferi s.l. transmission cycle in the western United States and quantifying their role in the spread and maintenance of Lyme disease requires further research.

1.Ecosystem engineers modify biophysical environments, create novel habitats, and change biodiversity, with the ultimate effect of modulating critical ecosystem functions. This review describes and synthesises approaches, methodologies, and analytical frameworks for quantifying how ecosystem engineers drive ecosystem functioning.2.We i) outline what variables to measure, how to measure them, and define the appropriate ecological and spatiotemporal scales for monitoring changes in both ecosystem engineers and ecosystem functioning; ii) illustrate experiments involving species exclusion or removal, addition or re-introduction, and comparative designs when experimental manipulation is not feasible; and iii) describe statistical, data-driven, and theory-driven approaches for estimating and forecasting the impact of ecosystem engineers on ecosystem functioning.3.In the Anthropocene, humans are a salient example of an ecosystem engineer. We discuss how to leverage the ecosystem engineer knowledge in the context of current anthropogenic change for achieving conservation, restoration, and climate-mitigation goals.4.We suggest evidence-based models and practises that can facilitate transformative changes in socio-ecological processes associated with ecosystem engineers. We conclude that implementing programs that monitor, forecast and apply the ecosystem engineer framework would sustain biological diversity and functional ecosystems.