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Ecological Intelligence

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Ecological Intelligence / Subject

bats

Peer-reviewed North America

Beaver dam analogues helped bats and some amphibians—but pond formation was the threshold for breeding

Evidence
Peer-reviewed
Geography
Okanogan-Wenatchee National Forest, Washington Cascades, USA
System
Montane streams and riparian restoration

WHAT THE EVIDENCE SAYS

Researchers compared 25 beaver-dam-analogue sites with paired controls for amphibians, 18 BDA-control pairs for bats, and natural beaver sites as a reference. Amphibian breeding occupancy was 24% at BDA sites, zero at paired controls and 88% at natural beaver sites. Bat activity was 3.9 times higher at BDA sites than controls and 4.7 times higher at beaver sites than controls. Amphibian response depended strongly on whether the structures created ponded habitat, while bat activity tracked slower water.

WHY IT MATTERS / OUR READ

For managers, the treatment is the habitat function—not the number of structures installed. If amphibian breeding is an objective, pond formation and hydroperiod need to be monitored explicitly; if bats are an objective, slower water and expanded foraging habitat may matter. Natural beaver sites also remind managers that an analogue may reproduce selected functions without reproducing the full complexity of beaver engineering.

CAVEATS / UNCERTAINTY

The BDA sites were only one to two years old. Amphibian BDA-control comparisons were paired, but comparisons with natural beaver sites were not always paired; occupancy and acoustic activity are not population-growth or recruitment measures. Results depend on local hydrology, species, permits and infrastructure constraints and should not be universalized.

SOURCE

Restoration Ecology — primary study
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In Washington mountain streams, amphibians bred at 24% of BDA sites versus none of paired controls, while bat activity rose 3.9-fold; natural beaver sites still delivered more complete habitat for amphibians.

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Peer-reviewed North America

White-nose syndrome is showing up in the Black Hills as a community shift, not only a species-by-species decline

Evidence
Peer-reviewed
Geography
Black Hills, South Dakota, USA
System
Temperate bat community

WHAT THE EVIDENCE SAYS

A study compared summer bat capture rates during early white-nose-syndrome invasion in 2017–2019 with 2022–2024, after the pathogen became established in the Black Hills. WNS-susceptible Myotis species declined steeply in captures, while several less-susceptible taxa increased, indicating a substantial change in the observed community.

WHY IT MATTERS / OUR READ

Disease can reorganize the community that monitoring encounters, not merely reduce a focal species. That changes how acoustic or capture baselines should be interpreted after invasion and makes ‘total bat activity’ a potentially misleading recovery metric.

CAVEATS / UNCERTAINTY

Capture rates are not complete population censuses and can respond to sampling conditions, habitat use and other ecological pressures. The authors themselves interpret the changes as reflecting WNS alongside broader ecological forces rather than assigning every trend to disease alone.

SOURCE

Journal of Mammalogy
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Summer captures fell steeply for WNS-susceptible Myotis after the fungus became established, while captures of less-susceptible taxa increased.

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Peer-reviewed Latin America & Caribbean

Eucalyptus cover filtered bat communities toward fewer functional roles in Brazil’s Atlantic Forest

Evidence
Peer-reviewed
Geography
Minas Gerais, Brazil
System
Atlantic Forest fragments in agricultural / plantation matrix

WHAT THE EVIDENCE SAYS

Mist-net and acoustic surveys detected 34 species/sonotypes. Across a 0–68% Eucalyptus-cover gradient, predicted functional richness and dissimilarity fell while functional redundancy rose; unique larger-bodied and diverse dietary guilds were less associated with Eucalyptus-dominated landscapes.

WHY IT MATTERS / OUR READ

Species counts alone can miss functional homogenization in production landscapes. Plantation extent and landscape composition may matter even when bats remain present.

CAVEATS / UNCERTAINTY

The study is observational across 12 fragments in one heavily altered landscape, so it cannot isolate plantation cover from every correlated land-use process or establish a universal plantation threshold.

SOURCE

Biodiversity and Conservation
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Across 12 forest fragments, Eucalyptus cover was the strongest landscape predictor of bat functional structure.

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Government data

Seven nights of listening found six bat species around the Sydney Opera House precinct

Evidence
Government data
Geography
Sydney Opera House, Royal Botanic Garden and The Domain, Sydney, Australia
System
Dense urban waterfront and parkland mosaic

WHAT THE EVIDENCE SAYS

A seven-night acoustic survey in March recorded more than 14,000 bat calls and identified six insectivorous species across the Sydney Opera House, Royal Botanic Garden and Domain precinct. The detections included the vulnerable eastern bent-winged bat, with activity recorded high on the Opera House structure as well as across nearby green space.

WHY IT MATTERS / OUR READ

Cities are not ecological blanks between reserves. Short-duration acoustic monitoring can reveal how built structures, waterfront edges and designed green space participate in habitat networks—and where more systematic urban-biodiversity monitoring may be warranted.

CAVEATS / UNCERTAINTY

Acoustic detections indicate activity, not population size, residency, roosting or reproductive success. Seven nights in one season cannot establish year-round habitat value or compare the precinct with other urban sites.

SOURCE

NSW Environment and Heritage · Monitoring update
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More than 14,000 ultrasonic calls—including a vulnerable bent-winged bat high on the Opera House—show how iconic civic landscapes can also function as nocturnal habitat.

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Peer-reviewed Europe

Bats and birds are not interchangeable pest-control allies in fruit orchards

Evidence
Peer-reviewed
Geography
Asturias, Spain
System
Apple and blueberry orchards

WHAT THE EVIDENCE SAYS

Researchers used dietary DNA metabarcoding to build tri-trophic networks linking birds and bats, spiders and insect pests in apple and blueberry crops. The networks separated birds and bats into different prey modules: bats tended to be more directly connected to pests, while birds more frequently showed intraguild predation on arthropod natural enemies. Among birds in apple orchards, higher abundance increased direct pest predation, whereas greater insectivory favored intraguild predation.

WHY IT MATTERS / OUR READ

Functional labels such as ‘insectivore’ can obscure who is actually eating whom. The management signal is to treat natural pest control as a food-web problem: predator identity, abundance and interaction pathways matter, and combining complementary predator groups may perform differently from simply maximizing predator richness.

CAVEATS / UNCERTAINTY

Diet metabarcoding and network structure show feeding relationships, not realized crop yield, pest suppression or pesticide reduction. Sampling periods and spatial coverage differed among predator groups, and the authors’ management recommendation should be tested against orchard-scale outcomes before being generalized.

SOURCE

Journal of Applied Ecology · Original evidence
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Dietary DNA networks in Spanish apple and blueberry systems found bats more directly linked to crop pests, while birds more often fed through intraguild pathways that can complicate simple ‘more predators is better’ assumptions.

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