Management history and climate as key factors driving natterjack toad population trends in Britain

Reduce competition from native amphibians

A replicated, site comparison study in 1985–2006 of 20 sites in the UK (McGrath & Lorenzen 2010) found that natterjack toad Bufo calamita populations did not increase following control of common toads Bufo bufo. However overall, natterjack population trends were positive at sites that had received species-specific management that included aquatic and terrestrial habitat management and common toad control. Trends were negative at unmanaged sites. Five of the 20 sites showed positive population trends, five showed negative trends and 10 trends were not significantly different from zero. Data on populations (egg string counts) and management activities over 11–21 years were obtained from the Natterjack Toad Site Register. Habitat management for toads was undertaken at seven sites. Management varied between sites, but included pond creation, adding lime to acidic ponds, maintaining water levels, vegetation clearance and implementation of grazing schemes. Translocations were also undertaken at seven of the 20 sites.

Translocate natterjack toads

A replicated, before-and-after study in 1985–2006 of natterjack toad Bufo calamita populations at 20 sites in the UK (McGrath & Lorenzen 2010) found that populations increased at sites established via translocations. The average population trend for translocation sites was significantly positive (0.10) while that for native sites did not differ significantly from zero (−0.04). Numbers of years of translocations of wild (including head-started) animals, but not captive-bred animals had a significant effect on population trends. Overall, five of the 20 sites showed positive population trends, five showed negative trends and 10 trends were not significantly different from zero. Data on populations (egg string counts) and management activities over 11–21 years were obtained from the Natterjack Toad Site Register. Translocations were undertaken at seven sites using wild-sourced (including head-starting) or captive-bred toads. Habitat management for toads was also undertaken at seven of the 20 sites.

Add lime to water bodies to reduce acidification

A replicated, site comparison study in 1985–2006 of 20 sites in the UK (McGrath & Lorenzen 2010) found that natterjack toad Bufo calamita populations increased with species-specific habitat management including adding limestone to ponds. In contrast, long-term trends showed population declines at unmanaged sites. Individual types of habitat management (aquatic, terrestrial or common toad Bufo bufo management) did not significantly affect trends, but length of management did. Overall, five of the 20 sites showed positive population trends, five showed negative trends and 10 trends did not differ significantly from zero. Data on populations (egg string counts) and management activities over 11–21 years were obtained from the Natterjack Toad Site Register. Habitat management for toads was undertaken at seven sites. Management varied between sites, but included pond creation, adding limestone to acidic ponds, maintaining water levels, vegetation clearance and implementing grazing schemes. Translocations were also undertaken at seven of the 20 sites using wild-sourced (including head-starting) or captive-bred toads.

Regulate water levels

A replicated, site comparison study in 1985–2006 of 20 sites in the UK (McGrath & Lorenzen 2010) found that natterjack toad Bufo calamita populations increased with species specific habitat management including maintenance of water levels. In contrast, long-term trends showed population declines at unmanaged sites. Individual types of habitat management (aquatic, terrestrial or common toad Bufo bufo management) did not significantly affect trends, but length of management did. Overall, five of the 20 sites showed positive population trends, five showed negative trends and 10 trends did not differ significantly from zero. Data on populations (egg string counts) and management activities over 11–21 years were obtained from the Natterjack Toad Site Register. Habitat management for toads was undertaken at seven sites. Management varied between sites, but included maintaining water levels, pond creation, adding lime to acidic ponds, vegetation clearance and implementing grazing schemes. Translocations were also undertaken at seven of the 20 sites using wild-sourced (including head-starting) or captive-bred toads.

(Summarised by: Rebecca K Smith)

Create ponds for natterjack toads

A replicated, before-and-after, site comparison study in 1985–2006 of 20 dune, heathland and salt marsh sites in the UK (McGrath & Lorenzen 2010) found that natterjack toad Bufo calamita populations tended to increase or be maintained with species specific habitat management including pond creation. In contrast, long-term trends showed population declines at unmanaged sites. Individual types of habitat management (aquatic, terrestrial or common toad Bufo bufo management) did not significantly affect trends, but duration of management did. Overall, five of the 20 sites showed positive population trends, five showed negative trends and 10 trends were not significantly different from zero. Data on populations (egg string counts) and management activities over 11–21 years were obtained from the Natterjack Toad Site Register. Habitat management for toads was undertaken at seven sites. Management varied between sites, but included pond creation, adding lime to acidic ponds, maintaining water levels, vegetation clearance and implementing grazing. Translocations were also undertaken at seven of the 20 sites using wild-sourced (including head-starting) or captive-bred toads.

Manage grazing regime

A replicated, site comparison study in 1985–2006 of 20 sites in the UK (McGrath & Lorenzen 2010) found that natterjack toad Bufo calamita populations increased with species specific habitat management including introduction of grazing to fields. Populations declined at unmanaged sites. Individual types of habitat management (aquatic, terrestrial or common toad Bufo bufo management) did not significantly affect trends, but length of management did. Overall, five of the 20 sites showed positive population trends, five showed negative trends and 10 showed no significant trend. Data on populations (egg string counts) and management activities over 11–21 years were obtained from the Natterjack Toad Site Register. Habitat management was undertaken at seven sites. Management varied between sites, but included introduction of grazing, pond creation, adding lime to acidic ponds, maintaining water levels and vegetation clearance. Translocations were also undertaken at seven of the 20 sites using wild-sourced (including head-started) or captive-bred toads.

Clear vegetation

A replicated, site comparison study in 1985–2006 of 20 sites in the UK (McGrath & Lorenzen 2010) found that natterjack toad Bufo calamita populations increased with species-specific habitat management that included vegetation clearance, in some cases with translocations. In contrast, long-term trends showed population declines at unmanaged sites. Individual types of habitat management (aquatic, terrestrial or common toad Bufo bufo management) did not significantly affect trends, but length of management did. Five of the 20 sites showed positive population trends, five showed negative trends and 10 trends were not significantly different from zero. Data on populations (egg string counts) and management activities over 11–21 years were obtained from the Natterjack Toad Site Register. Habitat management for toads was undertaken at seven sites. Management varied between sites, but included vegetation clearance, pond creation, adding lime to acidic ponds, maintaining water levels and implementing grazing schemes. Translocations were also undertaken at seven of the 20 sites using wild-sourced (including head-starting) or captive-bred toads.