Influence of weather on a population of soprano pipistrelle bats in West Wales, UK: a 20 year study estimates population viability

Andrews, Peter T.; Crump, R. G.; Harries, David J.; Andrews, Margaret

doi:10.3354/esr00720

Cited by 10 publications

(5 citation statements)

References 39 publications

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“…During a simulated year, we multiplied each colony size with a growth rate selected from a normal distribution with an expected value of 1 and a standard deviation ( SD ) of either 0.1 or 0.01, which remained constant across years and colonies. The two standard deviations represent high and low temporal variability in colony size, respectively, and are consistent with bat population dynamics reported in the literature (Andrews, Crump, Harries, & Andrews, 2016; Chauvenet, Hutson, Smith, & Aegerter, 2014; Schaub, Gimenez, Sierro, & Arlettaz, 2007). We simulated roost abandonment by randomly selecting a given percentage of colonies which would abandon their roost at the end of a simulated year and establish a new roost.…”

Section: Methodssupporting

confidence: 87%

Observer retention, site selection and population dynamics interact to bias abundance trends in bats

Dambly

Jones

Boughey

et al. 2020

Journal of Applied Ecology

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Many long‐term wildlife population monitoring programmes rely on citizen scientists for data collection. This can offer several benefits over traditional monitoring practices as it is a cost‐effective, large‐scale approach capable of providing long time series data and raising public environmental awareness. Whilst there is a debate about the quality of citizen science data, a standardised sampling design can allow citizen science data to be of a similar quality to those collected by professionals. However, many programmes use subjective, opportunistic selection of monitoring sites and this introduces several types of bias, which are not well understood. Using bat roost counts as a case study, we took a ‘virtual ecologist’ approach to simulate the effect of opportunistic site selection and uneven observer retention on our ability to accurately detect abundance trends. We simulated populations with different levels of temporal variability and site fidelity. Our simulations reveal that opportunistic site selection and low observer retention can result in biased trends and that these biases are magnified when monitored populations exhibit high levels of inter‐annual variation and low site fidelity. These results show that the synergistic effects of observer behaviour, site selection, and population dynamics lead to biased abundance trends in monitoring programmes. This study highlights the value of engaging and retaining citizen science observers, a standardised sampling design, and the collection of metadata. We conclude that monitoring programmes need to be aware of their focal species' temporal variability and site fidelity to adequately assess the potential bias caused by opportunistic site selection and low observer retention. Synthesis and applications. Accurate data on population changes are key for conservation success. Therefore, it is important that citizen science monitoring programmes assess and potentially quantify the biases present in their data. We demonstrate the applicability of an established simulation framework to assess the effect of biases on our ability to correctly detect abundance trends. Our findings highlight that monitoring programmes need to be aware of their study species’ temporal variability and site fidelity to assess and account for the effects of biased site selection and observer retention.

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Section: Methodssupporting

confidence: 87%

Observer retention, site selection and population dynamics interact to bias abundance trends in bats

Dambly

Jones

Boughey

et al. 2020

Journal of Applied Ecology

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“…Early spring corresponds to the most vulnerable period for bats as their energy reserves will be at their lowest following hibernation, and food availability is therefore critical. Thus, warm springs which cause both an increase in insect food supplies but also an extended feeding season for bats since prey becomes available earlier in the season may be highly favourable to the bats (but see Andrews et al 2016 who suggest that a delay in insect emergence may favour female pipistrelle bats in gestation/lactation). Considering the significant increase in spring temperatures in recent decades in the UK (Online Resource 8), there is strong support that climate warming has contributed to population growth.…”

Section: Landscape Characteristics Affect Colony Size At Different Spmentioning

confidence: 99%

Factors driving population recovery of the greater horseshoe bat (Rhinolophus ferrumequinum) in the UK: implications for conservation

et al. 2017

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Although populations of many bat species appear to be recovering in some European countries, the extrinsic and intrinsic factors driving these increases have not yet been assessed. Disentangling the benefits of conservation management from other factors such as climate change is a crucial step for improving evidence-based conservation strategies. We used the greater horseshoe bat (Rhinolophus ferrumequinum) as a case study for understanding the recovery of bat populations, as its north-western populations have increased substantially over the past two decades following severe population declines. Using summer roost count data from the UK National Bat Monitoring Programme spanning an 18 year period from 1997 to 2014, we investigated the effects of (i) landscape characteristics associated with the implementation of the agri-environment schemes on colony trends and size, and (ii) meteorological variables on annual colony growth rate. We also assessed the relationship between colony size and colony growth to investigate intrinsic factors such as an Allee effect. Our results indicated that colony size was positively related to a range of landscape features (e.g. amount of broadleaf woodland and grassland, and density of linear features) surrounding the roost, while the amount of artificial light at night had a significant negative effect. Spring temperatures and precipitation (the latter with a lag of one year) were associated with annual colony growth. We also identified a negative density-dependence effect within colonies. Though the conservation of essential landscape elements may have contributed to population increases in the long-term, we conclude that recent population recovery has also been driven by climate Communicated by Dirk Sven Schmeller.Electronic supplementary material The online version of this article (doi:10.1007/s10531-017-1320-1) contains supplementary material, which is available to authorized users. change. Finally we recommend that the conservation of photophobic bat species such as R. ferrumequinum should focus on both the improvement of foraging/commuting habitats and the creation of dark areas.

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“…Habitat preferences for P. pygmaeus are considered to be different than those of P. pipistrellus , with the former detected more frequently in riparian habitats and the latter detected in a wider variety of habitats, as also reported by Walsh and Harris (). This study has revealed that the Lledr valley is a potentially suitable foraging area for P. pygmaeus , which in Wales, may be at risk from climate change, since higher winter temperatures between January and March have been linked to previously a smaller population size (Andrews, Crump, Harries, & Andrews, ).…”

Section: Discussionmentioning

confidence: 94%

Habitat usage of Daubenton's bat (Myotis daubentonii), common pipistrelle (Pipistrellus pipistrellus), and soprano pipistrelle (Pipistrellus pygmaeus) in a North Wales upland river catchment

Todd

Williamson²

2019

Ecology and Evolution

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Distributions of Daubenton's bat ( Myotis daubentonii ), common pipistrelle, ( Pipistrellus pipistrellus ), and soprano pipistrelle ( Pipistrellus pygmaeus ) were investigated along and altitudinal gradient of the Lledr River, Conwy, North Wales, and presence assessed in relation to the water surface condition, presence/absence of bank‐side trees, and elevation. Ultrasound recordings of bats made on timed transects in summer 1999 were used to quantify habitat usage. All species significantly preferred smooth water sections of the river with trees on either one or both banks; P. pygmaeus also preferred smooth water with no trees. Bats avoided rough and cluttered water areas, as rapids may generate high‐frequency echolocation‐interfering noise and cluttered areas present obstacles to flight. In lower river regions, detections of bats reflected the proportion of suitable habitat available. At higher elevations, sufficient habitat was available; however, bats were likely restricted due to other factors such as a less predictable food source. This study emphasizes the importance of riparian habitat, bank‐side trees, and smooth water as foraging habitat for bats in marginal upland areas until a certain elevation, beyond which bats in these areas likely cease to forage. These small‐scale altitudinal differences in habitat selection should be factored in when designing future bat distribution studies and taken into consideration by conservation planners when reviewing habitat requirements of these species in Welsh river valleys, and elsewhere within the United Kingdom.

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Influence of weather on a population of soprano pipistrelle bats in West Wales, UK: a 20 year study estimates population viability

Cited by 10 publications

References 39 publications

Observer retention, site selection and population dynamics interact to bias abundance trends in bats

Observer retention, site selection and population dynamics interact to bias abundance trends in bats

Factors driving population recovery of the greater horseshoe bat (Rhinolophus ferrumequinum) in the UK: implications for conservation

Habitat usage of Daubenton's bat (Myotis daubentonii), common pipistrelle (Pipistrellus pipistrellus), and soprano pipistrelle (Pipistrellus pygmaeus) in a North Wales upland river catchment

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