Use nest covers to protect against human disturbance

Overall effectiveness category Awaiting assessment
Number of studies: 2
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Effectiveness

not assessed
Certainty

not assessed
Harms

not assessed

Calculating overall effectiveness category

Background information and definitions

Human recreational activity may cause damage to reptile nests. Cage covers over individual nests may be used to prevent damage in areas of high human traffic.

For studies that discuss the use of nest covers to protect against predation, see Threat: Invasive and other problematic species – Remove or control predators using fencing and/or aerial nets.

Study locations

Key messages

Two studies evaluated the effects of using nest covers to protect against human disturbance on reptiles. One study was in the USA and one was in Greece.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (2 STUDIES)

Reproductive success (2 studies): One of two replicated, controlled studies (including one paired study) in the USA and Greece found that loggerhead turtle nests that were covered with cages had similar hatching success compared to nests that were not covered. The other study found mixed effects of cages on hatching success of loggerhead turtle nests.

BEHAVIOUR (0 STUDIES)

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, paired study in 1996 in beaches in Florida, USA (Mroziak et al. 2000) found that covering loggerhead Caretta caretta turtle nests with individual cages did not improve hatching success in areas with high or low human footfall. Hatching success was similar between caged and uncaged nests in areas of high footfall (caged: 66–67%, uncaged: 66–71%) and low footfall (caged: 75–76%, uncaged: 66–76%). In May–October 1996, fifty-eight paired sea turtle nests were either uncovered or covered with square wire cages (76 cm square, 107 cm tall, 5 x 10 cm mesh) anchored 30 cm in the sand in both low (66 total nests, 4,209 caged eggs, 3,888 uncaged eggs, 20 beach users/hour, two beach zones) and high traffic beaches (50 total nests, 3,678 caged eggs, 4,991 uncaged eggs, 50 beach users/hour, two beach zones. Hatching success was determined by excavating nests three days after hatchlings emerged to count successfully hatched eggs.
Study and other actions tested
Referenced paper
Mroziak M.L., Salmon M. & Rusenko K. (2000) Do wire cages protect sea turtles from foot traffic and mammalian predators? Chelonian Conservation and Biology, 3, 693-698.
A replicated, controlled study in 1987–1995 on a sandy beach on Zakynthos Island, Greece (Kornaraki et al. 2006) found that covering loggerhead turtles Caretta caretta nests with individual metal cages resulted in variable hatching success compared to both uncaged nests left in situ and nests relocated to an on-beach hatchery. Over six years, hatching success in caged nests was lower in two years, higher in two years and similar in two years compared to in situ nests. Hatching success for caged nests varied from 44–72%, compared to 56–68% for uncaged in situ nests and 51–75% for nests moved to an on-beach hatchery. From 1988–1995, nests located within 7 m of the sea and in danger of inundation were moved to a beach hatchery (77 nests) as were nests located near invasive plants which had root systems that grow into nests. From 1990, nests located in beach areas with tourists were protected by 50 cm circular metal mesh cages buried 15 cm in the sand (88 nests). A further 313 nests were left uncaged and in situ. Nests were excavated following hatchling emergence to assess hatching success.
Study and other actions tested
Referenced paper
Kornaraki E., Matossian D.A., Mazaris A.D., Matsinos Y.G. & Margaritoulis D. (2006) Effectiveness of different conservation measures for loggerhead sea turtle (Caretta caretta) nests at Zakynthos Island, Greece. Biological Conservation, 130, 324-330.

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.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Reptile Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Use nest covers to protect against human disturbance Action Link	Awaiting assessment	2	Synopsis Link
Introduce and enforce regulations for reptile watching tours Action Link	No evidence found (no assessment)	0	Synopsis Link
Use signs and access restrictions to reduce disturbance Action Link	Awaiting assessment	1	Synopsis Link