Multi-taxa consequences of management for an avian umbrella species

Abstract

Whether management for so-called umbrella species actually benefits co-occurring biota has rarely been tested. Here, we studied consequences for multiple invertebrate taxa of two grounddisturbance treatments designed to support an avian umbrella species (Eurasian stone-curlew, Burhinus oedicnemus), and whether analysing ecological requirements across the regional species pool predicted beneficiaries. Responses were assessed for the abundance of five bird species of conservation concern, and the abundance, species richness and composition of carabids, staphylinids, other beetles (non-carabid, non-staphylinid), true bugs and ants, sampling 31258 individuals of 402 species in an extensively-replicated experiment across the UK's largest grassheath. Both treatments provided suitable habitat for the umbrella species, in contrast to controls.Treatment influenced the abundance of only one bird species; but carabid, other beetle and ant richness increased with one or both treatments, while staphylinid richness and abundance increased and true bug richness and abundance decreased with both treatments. Richness of 'priority' (rare, scarce or threatened) invertebrates a priori considered to share ecological requirements with the umbrella species (predicted beneficiaries) increased with both treatments. Resampling and rarefaction showed landscapes diversified by treatment supported a greater cumulative species richness of other beetles, ants and true bugs, and importantly priority invertebrates, than a landscape comprising only untreated controls. Such experiments provide strong evidence to assess co-benefits of umbrella species management, but are costly and time consuming. The systematic examination of the autoecological requirements of co-occurring taxa (the 'Biodiversity Audit Approach') successfully predicted likely beneficiaries. Demonstrating wider biodiversity benefits strengthens the case for avian conservation management.

Initial impact of a soil disturbance technique (disc harrowing) on Orthoptera in a grass heath in Breckland, UK

“…Green tiger beetles, Cicindela campestris, were also seen on the disc-harrowed strips along with many species of Hymenoptera. Hawkes et al (2019a) report that ground-disturbance increased the numbers of woodlark, Lullula arborea, while multi-taxa invertebrate responses were mixed in response to various ground treatments (Hawkes et al 2019b), with only 'priority' carabid beetles influenced by cultivation treatment. Hawkes et al (2019b) further outlined that landscapes with soil disturbance treatments had a higher species richness of ants, beetles, and true bugs than those without.…”

Placement, survival and predator identity of Eurasian Curlew Numenius arquata nests on lowland grass-heath

“…At the study-area scale, the placement of control points was restricted to outside the STANTA impact area, and GLMs examined fixed effects of treatment (two levels: disturbed vs. undisturbed grassland) and vegetation strata (two levels: calcareous/young grassland vs older acidic grassland). We did not examine the effects of site on nest placement as the two study sites both contained experimental ground-disturbance plots and were comparable in terms of vegetation structure (Hawkes et al, 2019b). For the homerange scale, we sampled three random points within a 164 m radius (of each nest) and GLMs examined fixed effects of treatment (two levels) but not vegetation strata, as most (38/41) home ranges contained only a single stratum.…”

“…Disturbed grassland is characteristically bare and short compared to uncultivated grassland (Dolman & Sutherland, 1994;Hawkes et al, 2019b). Curlew may have placed nests on this habitat because it allows greater vigilance (to facilitate and evade predator detection, Amat & Masero, 2004) and a greater abundance of some important prey (confirmed experimentally by Hawkes et al, 2019b) than the surrounding grassland. Although we did not examine whether ground-disturbance detail matters (to avoid overparameterizing the models), most nests were on shallowcultivated plots (n = 17, 41.5%), with few on deep-cultivated plots (n = 3, 7.3%).…”

“…Most lowland Curlew breed on dry grasslands and heathland (Table S1, Johnstone et al, 2017) where conservation management can radically alter habitat structure. Within these habitats, physical ground-disturbance is increasingly advocated as a land management intervention for other rare, scarce and threatened species, such as Stone-Curlew Burhinus oedicnemus and Woodlark Lullula arborea (Fuller et al, 2017;Hawkes et al, 2019b); however, it is not known whether this influences Curlew nest placement or breeding success. Understanding whether Curlew nests on disturbed grassland are easily visible to corvid nest predators, or conversely, whether placement of disturbed-plots can be used to manipulate nest placement into areas protected from mammalian predators, would better inform such management on sites with breeding Curlew.…”

Experimental evidence that novel land management interventions inspired by history enhance biodiversity

“…Studies in the inner part of STANTA were precluded by potential unexploded ordnance (see Figure S1 in Supporting Information), but otherwise, treatments and controls were randomly distributed across the study area, stratified across four non-randomly distributed grassland strata (following Hawkes, Smart, Brown, Jones, Lane, et al, 2019) S1).…”