Using Butterflies as indicators of Biodiversity
I recently took my woodland ecology students on a field visit to Rowland Wood, East Sussex, to meet up with Butterfly Conservation expert Neil Hulme, Fritillaries for the Future Project Officer. The purpose of the visit was to view how effective woodland and deer management has played an integral role in the breeding of the Small Pearl-bordered Fritillary. This was exciting news as Rowland Wood is the only site in the South East of England where the Small Pearl-bordered Fritillary exist.
Small Pear-bordered Fritillary (Image courtesy of Butterfly Conservation)
So how do the habits of deer and their management relate to butterfly conservation? Many important species of Lepidoptera (butterflies) feed on upon the nectar of woodland flora and lay their eggs in and amongst low lying shrubs and plants. Butterflies are specialist feeders and rely directly on a very limited number of plant species. The diversity of butterflies within woodland is specifically related to the frequency and diversity of plant richness and the variations of light and shade intensity. This is also indicative to grassland habitats as well as woodlands. Butterfly's relay on the first few vertical feet of woodland vegetation to complete their lifecycle. This area of vegetation is also the main food source for deer.
A noticeable decline in butterfly species within a woodland may indicate that there is intense browsing and grazing by populations of deer species on a level that is too high to be supported by the woodland. Non-native deer species such Fallow and Muntjac are intensive browsers and grazers. They feed profusely upon the layers of vegetation relied upon by butterfly's and create whats known as a browse line. A low lying area that is devoid of vegetation.
Browse line created by predation from Fallow deer at on Ashdown Forest.
Butterfly’s are a good indicator of diverse woodland habitat. A woodland without butterfly's is a woodland that is lacking in biodiversity. In order to increase vegetative biodiversity sensitive deer management and woodland practices such as coppicing and ride mowing will boost the chances of vegetative growth. This is where we as hunters and deer managers play an important role in helping improve our native woodlands. So when heading out in the spring woods for roebuck, think on and keep an eye out for the humble butterfly.
Preserved sample of a Small Pearl-Bordered Fritillary.
Checkout my Instagram post on this visit for even more information https://instagram.com/p/BL5rB31jUC3/