Action

Create or restore forests

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • Six studies evaluated the effects of creating or restoring forests on reptile populations. Three studies were in the USA, two were in Australia and one was in Mexico.

COMMUNITY RESPONSE (3 STUDIES)

  • Richness/diversity (3 studies): One of two replicated studies (including one randomized, controlled study) in the USA and Australia found that restored and natural riparian forest had similar reptile species richness. The other study found that restored forest areas had higher reptile species richness than remnant forest areas. One replicated, site comparison study in Australia found that the type of restoration had mixed effects on reptile species richness in tropical and subtropical areas.

POPULATION RESPONSE (5 STUDIES)

  • Abundance (5 studies): Two of three replicated studies (including two controlled, before-and-after studies) in the USA and Mexico found that areas of restored forest had similar abundances of snakes and six lizard species as unrestored areas. The other study found that restoring forest stands had mixed effects on the abundance of reptiles. One replicated, site comparison study in Australia found that areas with different restoration types had similar reptile abundance in tropical and subtropical areas. One replicated, randomized, controlled study in Australia found that restored forest areas had higher reptile abundance than remnant forest areas.

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

  1. A replicated, site comparison study in 2000–2001 in tropical and subtropical rainforests in Queensland and New South Wales, Australia (Kanowski et al. 2006) found that overall reptile richness, but not abundance, varied by restored forest type, depending on the region and species’ habitat specialism. In the tropics, management type affected overall reptile species richness (ecological restoration: 0.9–1.0 species/site, mixed timber plantation: 0–0.4, young monoculture plantation: 0–1.4, old monoculture plantation: 0.1–1.5, natural regrowth: 0–0.4, converted pasture: 0–0.01, old-growth forest: 0.1–2.2) but not abundance (restoration: 9.6 individuals/site, mixed: 2.8, young: 10.4, old: 6.0, regrowth: 0.8, pasture: 0.5, old-growth: 8.8). In the subtropics, management type did not affect overall species richness (restoration: 0–1.0, mixed: 0–0.7, young: 0–0.6, old: 0.2–0.4, regrowth: 0.2–0.4, pasture: 0–0.2, old-growth: 0.4–1.3) or abundance (restoration: 13.6, mixed: 10.7, young: 2.4, old: 1.3, regrowth: 17.6, pasture: 0.3, old-growth: 4.0). Rainforest-specialist species richness varied by management type in both tropical and subtropical regions and were only recorded in restoration plantings, old plantations, and old-growth forest in the tropics and in young and old plantations, natural regrowth and old-growth forest in the subtropics (see paper for individual species results). Reptiles were monitored in ecological restoration plantings (19 sites), mixed timber plantations (15), young monoculture timber plantations (10), old monoculture timber plantations (20), natural regrowth (10), converted to pasture (10), and unmanaged old growth rainforest (20) in subtropical and tropical rainforest. Visual searches were carried out in one 0.3 ha plot/site (30 minutes/search) on three occasions/site between October 2000–November 2001.

    Study and other actions tested
  2. A replicated, site comparison study in 1999–2000 of five riparian forest sites in California, USA (Queheillalt & Morrison 2006) found that reptile species richness in restored riparian forest was similar to that in natural riparian forest. Similar numbers of reptile species (4 species) were found in restored riparian forest compared to natural riparian forest (data reported as statistical model outputs). The authors reported that species abundant in the restored sites tended to be generalist species (e.g. coast garter snakes Thamnophis elegans terrestris) and that forest specialists (e.g. northern alligator lizards Elgaria coerulea) were present in the natural forest but not in the restored forest. Restoration, which included planting of woody riparian species, commenced between 1996 and 1998. In 1996–1998, a total of 15 ha of woody riparian species and 2.4 ha of freshwater wetland species were planted. Three restored sites (17,400 m2, 28,000 m2, 65,000 m2) were compared to two mature riparian forest sites (47,420 m2 and 24,780 m2). Reptiles were sampled using pitfall traps during May–August 2000 and visual surveys (25 x 25 m area).

    Study and other actions tested
  3. A replicated, controlled, before-and-after study in 2000–2006 in three sites of riparian forest in central New Mexico, USA (Bateman et al. 2008, likely same experimental set-up as Bateman et al. 2009) found that restoring forest through removing non-native vegetation and either burning the removed vegetation or planting native shrubs resulted in no change in the abundance of six lizard species. The effect of burning the removed vegetation and planting native shrubs cannot be separated from the effect of vegetation removal. Over a period of 1–3 years since removal, abundance of the six most common lizards (5 other species detected but not included in analysis due to small sample sizes) remained similar for restored and unmanaged sites (data reported as statistical model outputs). In 2003–2005, four riparian sites each within three regions were selected for non-native vegetation removal (3 sites/region) or no vegetation removal (1 site/treatment). Removal consisted of mechanical removal with chainsaws and herbicide (Garlon) application to stump sprouts. One removal site/region also had all removed vegetation burned, and another also had native shrubs planted. In June–September 2001–2006, abundance of lizards was surveyed at all sites with drift-fencing, pitfall and funnel traps (3 trapping arrays/site, checked 3 times/week).

    Study and other actions tested
  4. A replicated, controlled, before-and-after study in 2000–2006 in three areas of mixed riparian forest in north, middle and south Mexico (Bateman et al. 2009, likely same experimental set-up as Bateman et al. 2008) found that restoring forest through removing non-native vegetation and either planting native shrubs or burning slash piles did not increase overall snake abundance. The effect of planting native shrubs and burning slash piles cannot be separated from the effect of vegetation removal. Snake abundance remained similar in restored and unmanaged sites (data reported as statistical model outputs). Fourteen species of snake were counted in the sites over seven years of surveys. Snakes were monitored in 12 sites (20 ha each) in 2000–2006 from three areas of forest (four sites/area). In 2003–2005, the sites in each area were managed by either removing non-native plants (using chainsaws and herbicide), or removing non-native plants and planting native shrubs, or removing non-native plants and burning slash piles, or not managed at all (see original paper for details). Snakes were monitored using drift fences with pitfall and tunnel traps (‘arrays’; 3 arrays/site) in June–July 2000 and June–September 2001–2006.

    Study and other actions tested
  5. A replicated, randomized, controlled study in 2011–2012 in upland forest in Queensland, Australia (Shoo et al. 2014) found that reptile captures and species richness tended to be higher in restoration plantings than remnant forest, particularly when coarse woody debris was added. Results were not statistically tested. Reptile captures and species richness tended to be highest in restoration plantings with added coarse woody debris (captures: 3.7–4.0 individuals/site; species richness: 2.0 reptiles/site), followed by restoration plantings without added coarse woody debris (1.5, 0.7), and lowest in remnant forest without added debris (0.8, 0.5) or remnant forest with coarse woody debris removed (0.3, 0.2). In November 2011–January 2012, five treatments were applied four times each in four sites (60 m x 40 m sites): restoration planting (native trees and shrubs) with added salvaged log piles; restoration planting with added fence post piles; restoration planting with no debris added; remnant forest with no debris added; and remnant forest with all woody debris removed. Restoration plantings were 0–7 years old when coarse woody debris was added. Reptiles were surveyed in either March or August 2012 and again in December 2012.

    Study and other actions tested
  6. A replicated, site comparison study in 2012–2014 in saltcedar Tamarix ramosissima-cottonwood Populus fremontii forest along a river in Utah, Arizona and Nevada, USA (Mosher & Bateman 2016) found that restoring forest stands through replanting native species, managing vegetation using cutting and herbicides, and redirecting water flow to reduce dominance of invasive saltcedar had mixed effects on overall lizard abundance. Trapping surveys indicated that overall lizard abundance was similar in restored stands (127–171 lizards/site/100 trap nights) compared to unrestored stands (62–74), whereas visual encounter surveys found that overall reptile abundance was greater at restored sites (results reported as statistical tests). See original paper for the effects of restoration on individual species. In winter–spring 2012–2013, restoration of saltcedar-cottonwood/willow Salix spp stands was carried out along the Virgin River, including: mechanically removing 50% of saltcedar and Russian olive Elaegnus angustifolia, spraying stumps with herbicide, transplanting native plants and introducing/redirecting water flows by trenching. Saltcedar in Utah was subject to biocontrol by northern tamarisk beetles Diorhabda carinulata from 2006 (see original paper for details). Reptiles were monitored in two restored and six unrestored stands in May–July 2013–2014 using drift fences with pitfall and funnel traps (1,060 total trap days) and visual encounter surveys (3 transects/site, see original paper for details).

    Study and other actions tested
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?

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Reptile Conservation

This Action forms part of the Action Synopsis:

Reptile Conservation
Reptile Conservation

Reptile Conservation - Published 2021

Reptile synopsis

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What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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