The distribution and decline of a widespread butterflyLycaena phlaeasin a pastoral landscape

Abstract

Summary 1. Ecological specialists are often regarded as most likely to be threatened by anthropogenic habitat changes but few relevant data are available on changes in the status of widespread species. 2. Grid square distribution maps have been used widely to measure rates of decline and target conservation resources but it is known that coarse grain mapping is not appropriate to identify declines in widespread species that initially contain numerous local populations per grid cell. Changes in the status of widespread species need to be quantified. 3. Present‐day habitat associations, determined from over 2000 transect counts, combined with data on historical and present‐day habitat distributions, reveal that the area of occupancy and population‐level rate of decline of the Small Copper butterfly Lycaena phlaeas is likely to have been of the order of 92 and 89% respectively, in 35 km2 of North Wales. Similar data on the species' major host plants Rumex acetosa and R. acetosella indicate possible declines in area occupied of 48 and 91%. If a 1‐km2 grid was applied to the landscape, and if L. phlaeas, R. acetosa, and R. acetosella had occupied all 1‐km2 cells in the study area in 1901 (non‐limestone cells for R. acetosella only), their declines would only have been recorded as 15, 9, and 35% respectively. 4. Many declining ecological specialists are threatened with extinction because of their initial rarity. At a population level, however, they may or may not be declining faster than less specialised species. The results presented here illustrate that some widespread species may have declined as much as many of Britain's rarities.

Relative importance of habitat area, connectivity, management and local factors for vascular plants: spring ephemerals in boreal semi-natural grasslands

“…Additionally, a clear prerequisite for the persistence of local butterXy populations is the occurrence of their host plant. Ultimately, the decline of a butterXy species can be linked with a decline in its host plant (León-Cortés et al 2000). In our study area, Corydalis solida is the main food plant for the larvae of Parnassius mnemosyne.…”

Variabilité spatio-temporelle des insectes mangeurs de fruits utilisés comme bioindicateurs en Afrique de l'ouest

“…All the considered species are however very sensitive to ecosystem disturbance, in one sense or the over. It has been demonstrated in other studies that widespread species may decline just as much as rare species (Leon-Cortes et al, 2000). In these ecosystems, all species were disfavored by cropping activities, except P. marginata.…”

Butterfly Assemblages in Fragmented Meadow Habitats of the Pre-Carpathian Lowland (Bereg Plain, Sw Ukraine)

“…The surveys were carried ot by standard transect walks in 2012 and 2013 in four and five repetitions, respectively (2012: [16][17][18] . Most butterflies were readily identified by observation.…”