Disturb soil/sediment surface

Overall effectiveness category Awaiting assessment
Number of studies: 2
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Calculating overall effectiveness category

Background information and definitions

Many habitats depend on disturbances such as grazing to maintain structural habitat diversity, for example through trampling, and therefore support populations of species that depend on that disturbance. Tilling or soil scarification may be used as a way to disturb soils where grazing is not a viable option.

Study locations

Key messages

Two studies evaluated the effects of disturbing the soil/sediment surface on reptile populations. One study was in Sweden and the other was in the USA.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Abundance (1 study): One replicated, controlled, before-and-after study in Sweden found that after sand patches were created by soil scarification within clearings created by tree felling, sand lizards colonized, abundance then declined, but then increased once more, larger clearings were created.

BEHAVIOUR (1 STUDY)

Use (1 study): One randomized study in the USA found that tilled areas were used more frequently by Blanding’s turtles for nesting than mown or weeded areas.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated, controlled, before-and-after study in 1988–2004 in sandy pine heath in south-central Sweden (Berglind 2005) found where sand patches were created through disturbing the soil surface in areas where trees were cleared, sand lizards Lacerta agilis colonized, abundance then declined, but then increased after more sand patches in further clearings were created. After soil scarification and tree felling, sand lizards gradually colonized newly created habitat patches and eventually abandoned unmanaged habitat after 16 years (see original paper). During the first 10 years after sand patch creation, female sand lizard abundance declined (9–11%) but increased annually (11–19%) after a second, larger-scale clearing and sand patch creation programme was carried out. In particular, subadult lizard abundance increased more after the second creation programme (after first programme <10% increase; after second programme >150% increase in relative population size). Restoration was first carried out in 1988 and 1992 when nine 1–2 ha lizard-appropriate habitat patches in two sites were managed by tree felling and creating sand patches. A second restoration programme took place in the same two sites in 1999 and 2001, creating eighteen 10 ha habitat patches by tree felling, soil scarification and excavating 7–11 100–200 m² sand patches/site. Sand lizards were monitored from May–September in 1988–2004 by hand capture in unmanaged and managed areas of the sites.
Study and other actions tested
Referenced paper
Berglind S.Å. (2005) Population dynamics and conservation of the sand lizard (Lacerta agilis) on the edge of its range. PhD. Uppsala Universitet.
A randomized study in 2006 and 2008 in wetlands in New York, USA (Dowling et al. 2010) found that female Blanding’s turtles Emydoidea blandingii preferred nesting in plots where soil was disturbed by tilling compared to weeded or mown plots. In 2006, nine of 10 monitored female turtles nested, of which seven nested in tilled plots and two in mowed plots. In 2008, six turtles nested, of which four nested in tilled plots, one in a weeded plot and one off the treatment plots. Two turtles nested in the same physical plot each year, in spite of a change in management. In 2006, thread trailing revealed that all female turtles explored or had been placed on each plot type before choosing where to nest. Eight sites around the edge of a fenced 12 ha wetland were monitored for turtle nesting activity. Each site contained three plots (5 x 7 m) with one of three managements randomly applied in 2006 and 2008: tilled to a depth of 15 cm (24 total plots), mowed to 5 cm height or 90% hand-weeded. Nesting activity was monitored by visual searches and radio tracking or by attaching a bobbin and thread to female turtles in May and June 2006 and 2008 (10 total turtles monitored).
Study and other actions tested
Referenced paper
Dowling Z., Hartwig T., Kiviat E. & Keesing F. (2010) Experimental management of nesting habitat for the Blanding's turtle (Emydoidea blanditigii). Ecological Restoration, 28, 154-159.

Please cite as:

Sainsbury K.A., Morgan W.H., Watson M., Rotem G., Bouskila A., Smith R.K. & Sutherland W.J. (2021) Reptile Conservation: Global Evidence for the Effects of Interventions for reptiles. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.