Clean and Green Urban Water Bodies Benefit Nocturnal Flying Insects and Their Predators, Insectivorous Bats

Nocturnal arthropods form the prey base for many predators and are an integral part of complex food webs. However, there is limited understanding of the mechanisms influencing invertebrates at urban water bodies and the potential flow-on effects to their predators. This study aims to: (i) understand the importance of standing water bodies for nocturnal flying insect orders, including the landscape- and local-scale factors driving these patterns; and (ii) quantify the relationship between insects and insectivorous bats. We investigated nocturnal flying insects and insectivorous bats simultaneously at water bodies (n = 58) and non-water body sites (n = 35) using light traps and acoustic recorders in Melbourne, Australia. At the landscape scale, we found that the presence of water and high levels of surrounding greenness were important predictors for some insect orders. At the water body scale, low levels of sediment pollutants, increased riparian tree cover and water body size supported higher insect order richness and a greater abundance of Coleopterans and Trichopterans, respectively. Most bat species had a positive response to a high abundance of Lepidopterans, confirming the importance of this order in the diet of insectivorous bats. Fostering communities of nocturnal insects in urban environments can provide opportunities for enhancing the prey base of urban nocturnal insectivores.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

Bats in a Farming Landscape Benefit from Linear Remnants and Unimproved Pastures

Schemes designed to make farming landscapes less hostile to wildlife have been questioned because target taxa do not always respond in the expected manner. Microbats are often overlooked in this process, yet persist in agricultural landscapes and exert top-down control of crop pests. We investigated the relationship between microbats and measures commonly incorporated into agri-environment schemes, to derive management recommendations for their ongoing conservation. We used acoustic detectors to quantify bat species richness, activity, and feeding in 32 linear remnants and adjacent fields across an agricultural region of New South Wales, Australia. Nocturnal arthropods were simultaneously trapped using black-light traps. We recorded 91,969 bat calls, 17,277 of which could be attributed to one of the 13 taxa recorded, and 491 calls contained feeding buzzes. The linear remnants supported higher bat activity than the fields, but species richness and feeding activity did not significantly differ. We trapped a mean 87.6 g (±17.6 g SE) of arthropods per night, but found no differences in biomass between land uses. Wider linear remnants with intact native vegetation supported more bat species, as did those adjacent to unsealed, as opposed to sealed roads. Fields of unimproved native pastures, with more retained scattered trees and associated hollows and logs, supported the greatest bat species richness and activity. We conclude that the juxtaposition of linear remnants of intact vegetation and scattered trees in fields, coupled with less-intensive land uses such as unimproved pastures will benefit bat communities in agricultural landscapes, and should be incorporated into agri-environment schemes. In contrast, sealed roads may act as a deterrent. The "wildlife friendly farming" vs "land sparing" debate has so far primarily focussed on birds, but here we have found evidence that the integration of both approaches could particularly benefit bats.Financial support was provided by a “Science Grant” from The Paddy Pallin Foundation in partnership with the Royal Zoological Society of NSW (http://www.paddypallinfoundation.org.au/index.php/current/sciencegrants), a WildCountry Science Council student top-up (http://www.wilderness.org.au/campaigns/wildcountry/wild-country-science-council-members), the Australian Government’s Department of Industry, Innovation, Science, Research and Tertiary Education Australian Postgraduate Award to PL (http://www.innovation.gov.au/research/researchblockgrants/pages/australianpostgraduateawards.aspx), and a CSIRO student top-up scholarship to PL (http://www.csiro.au/Portals/Careers/Work-experience-and-scholarships/Postgraduate-scholarships/Flagship-Postgrad-Scholarships.aspx). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Global synthesis of conservation studies reveals the importance of small habitat patches for biodiversity

Island biogeography theory posits that species richness increases with island size and decreases with isolation. This logic underpins much conservation policy and regulation, with preference given to conserving large, highly connected areas, and relative ambivalence shown toward protecting small, isolated habitat patches. We undertook a global synthesis of the relationship between the conservation value of habitat patches and their size and isolation, based on 31 systematic conservation planning studies across four continents. We found that small, isolated patches are inordinately important for biodiversity conservation. Our results provide a powerful argument for redressing the neglect of small, isolated habitat patches, for urgently prioritizing their restoration, and for avoiding simplistic application of island biogeography theory in conservation decisions.Peer reviewe

Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases

Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises

Value of large-scale linear networks for bird conservation: A case study from travelling stock routes, Australia

a b s t r a c t We investigated the potential role of the travelling stock route network, Australia, in the conservation of declining birds. We surveyed 32 linear remnants and 24 adjacent agricultural fields of crop, native pasture or exotic pasture, for woodland birds. Compared to surrounding agricultural fields, linear remnants provided better habitat for woodland birds. Within the remnants, vegetation structural complexity was a better predictor of woodland bird richness than remnant width. In the fields the highest number of species was found in native pastures, and there was also a positive association with the number of scattered trees retained. Interestingly, there was a negative association with the width of the stock route running next to the field, with narrower linear remnants providing a greater source of avian visitors to farmland. Our findings suggest that investments in woodland bird habitat may be best spent protecting smaller, better quality remnants, or enhancing structural complexity of the vegetation already present. Existing networks of linear remnants present a low cost opportunity for regional scale conservation across extensively cleared agricultural landscapes

Scholarly shortcomings and a lack of evidence beleaguer bee sampling critique: A response to Prendergast and Hogendoorn (2021)

Prendergast and Hogendoorn (2021) comment on the ‘methodological shortcomings’ of Australian bee studies, but forgo the opportunity to provide a balanced assessment of the relative merits of different survey methods to inform future studies (for a constructive example of this see Packer & Darla‐West 2021). Instead, they single out standardised survey tools for bees (pan traps and vane traps) as the focus of their criticism and strongly advocate sweep netting and direct observation by skilled entomologists as the ‘pre‐eminen[t]’ methods for bee surveys. They consistently criticise the published work of a small number of Australian authors (particularly ourselves) and claim that any results from pan trap and vane trap samples lead to ‘incorrect conclusions’ about bee biodiversity

Scholarly shortcomings and a lack of evidence beleaguer bee sampling critique: A response to Prendergast and Hogendoorn

Prendergast and Hogendoorn (2021) comment on the ‘methodological shortcomings’ of Australian bee studies, but forgo the opportunity to provide a balanced assessment of the relative merits of different survey methods to inform future studies (for a constructive example of this see Packer & Darla‐West 2021). Instead, they single out standardised survey tools for bees (pan traps and vane traps) as the focus of their criticism and strongly advocate sweep netting and direct observation by skilled entomologists as the ‘pre‐eminen[t]’ methods for bee surveys. They consistently criticise the published work of a small number of Australian authors (particularly ourselves) and claim that any results from pan trap and vane trap samples lead to ‘incorrect conclusions’ about bee biodiversity

Relationships among ecological traits of wild bee communities along gradients of habitat amount and fragmentation

Amount of semi-natural habitats (permanent grasslands, woodlands and hedgerows) and their level of ragmentation are among the main determinants of wild bee diversity in agricultural landscapes. However, their impact on the distribution of bee ecological traits has received little attention. In this study, we aimed to explore whether changes in the distribution of bee ecological traits along gradients of habitat amount and fragmentation were due to a direct effect of landscape context on multiple traits (‘response traits’) or to a correlation of response traits with other ecological traits not involved in the response of bee species to landscape context. In two study regions in southwest France and southeast Australia, we used a RLQ analysis (three-table ordination method) to link bee traits with habitat amount and fragment isolation measured at the landscape scale. We found that bee ecological traits shifted at the community-level in association with landscape gradients, whereas species-level associations among bee traits and phylogenetic clustering in bee communities were of only minor importance in determining such shifts. We found that traits such as body size and nest location were closely linked to habitat amount and fragmentation. We also observed regionally-specific relationships among ecological traits, suggesting that the regional species pool can play an important role in determining the response of bee communities to habitat amount and fragmentation. Our findings suggest that improved knowledge about how trait-based responses mediate the impact of landscapes on wild bee communities will allow better prediction and understanding of subsequent effects on ecosystem functioning