Collected Evidence: Collected Evidence: Dig trenches around culverts under roads/railways One study evaluated the effects on mammals of digging trenches around culverts under roads and/or railways. This study was in South Africa. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): A replicated, randomized, controlled, before-and-after study in South Africa found that digging trenches alongside culverts did not reduce mammal mortality on roads. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2524https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2524Mon, 08 Jun 2020 11:41:56 +0100Collected Evidence: Collected Evidence: Install fences around existing culverts or underpasses under roads/railways Four studies evaluated the effects on mammals of installing fences around existing culverts under roads/railways. Two studies were in the USA one was in Portugal and one was in South Africa. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Survival (3 studies): Two out of three before-and-after studies (including a controlled and a site comparison study), in the USA, Portugal and South Africa, found that installing or enhancing roadside fencing alongside existing culverts reduced mammal road mortality whilst one study found that such fences did not alter mammal road mortality. BEHAVIOUR (1 STUDY) Use (1 study): A replicated, randomized, controlled, before-and-after study in the USA found that fences installed to funnel animals to existing culverts did not increase culvert use by bobcats. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2525https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2525Mon, 08 Jun 2020 11:56:51 +0100Collected Evidence: Collected Evidence: Install barrier fencing along roads Twelve studies evaluated the effects on mammals of installing barrier fencing along roads. Eight studies were in the USA, one each was in Canada, Germany and Brazil and one spanned the USA, Canada and Sweden. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (9 STUDIES) Survival (9 studies): Three controlled studies, in the USA, Germany and Brazil, found that roadside fencing or equivalent barrier systems reduced the numbers of mammals, including wildcats and coypu, killed by vehicles on roads. Two before-and-after studies, in the USA, found that roadside fencing with one-way gates to allow escape from the road, reduced the number of collisions between vehicles and deer. A study in the USA found that a 2.7-m-high fence did not reduce road-kills of white-tailed deer compared to a 2.2-m-high fence. A controlled, before-and-after study in the USA found that barrier fencing with designated crossing points did not significantly reduce road deaths of mule deer. A replicated, controlled, before-and-after study in Canada found that electric fences, (along with an underpass beneath one highway), reduced moose-vehicle collisions. A review of fencing studies from USA, Canada and Sweden, found that longer fencing along roadsides led to a greater reduction of collisions between large mammals and cars than did shorter fence sections. BEHAVIOUR (5 STUDIES) Behaviour change (5 studies): A controlled, before-and-after study in the USA found that 2.3-m-high fencing in good condition prevented most white-tailed deer accessing a highway. A replicated, controlled, before-and-after study in Canada found that electric fences reduced moose access to highways. Three studies (two replicated), in the USA, found that higher fences (2.4–2.7 m) prevented more white-tailed deer from entering highways than did fences that were 2.2 m high, 1.2 m high with outriggers or 1.2–1.8 m high. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2567https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2567Tue, 09 Jun 2020 14:55:48 +0100Collected Evidence: Collected Evidence: Install barrier fencing and underpasses along roads Fifty-five studies evaluated the effects on mammals of installing barrier fencing and underpasses along roads. Twenty-seven were in the USA, nine were in Canada, seven were in Australia, two each were in Spain, Portugal, the UK and Sweden, one each was in Denmark, Germany and Croatia and one was a review covering Australia, Europe and North America. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (15 STUDIES) Survival (15 studies): Eleven of 15 studies (including 12 before-and-after studies and two site comparisons), in the USA, Australia, Sweden and Canada, found that installing underpasses and associated roadside barrier fencing reduced collisions between vehicles and mammals. Three studies found that the roadkill rate was not reduced and one study found that vehicle-mammal collisions continued to occur after installation. BEHAVIOUR (52 STUDIES) Use (52 studies): Seventeen of 18 studies (including 10 before-and-after studies) in the USA, Canada and Sweden, which reported exclusively on ungulates, found that underpasses installed along with roadside barrier fencing were used by a range of ungulate species. These were mule deer, mountain goat, pronghorn, white-tailed deer, elk, moose and Florida Key deer. The other study found that underpasses were not used by moose whilst one of the studies that did report use by ungulates further reported that they were not used by white-tailed deer. Further observations from these studies included that elk preferred more open, shorter underpasses to those that were enclosed or longer, underpass use was not affected by traffic levels and that mule deer used underpasses less than they used overpasses. Thirty-four studies (including four before-and-after studies, seven replicated studies, three site comparisons and two reviews), in the USA, Canada, Australia, Spain, Portugal, the UK, Denmark, Germany, Croatia and across multiple continents, that either studied mammals other than ungulates or multiple species including ungulates, found that underpasses in areas with roadside fencing were used by mammals. Among these studies, one found that small culverts were used by mice and voles more than were larger underpasses, one found that bandicoots used underpasses less after they were lengthened and one found that culverts were used by grizzly bears less often than were overpasses. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2571https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2571Wed, 10 Jun 2020 08:35:55 +0100Collected Evidence: Collected Evidence: Install barrier fencing along railways One study evaluated the effects on mammals of installing barrier fencing along railways. This study was in Norway. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): A before-and-after study in Norway found that fencing eliminated moose collisions with trains, except at the fence end. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2590https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2590Thu, 11 Jun 2020 09:13:01 +0100Collected Evidence: Collected Evidence: Install acoustic wildlife warnings along roads Two studies evaluated the effects on mammals of installing acoustic wildlife warnings along roads. One study was in Demark and one was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (2 STUDIES) Behaviour change (2 studies): A before-and-after study in Denmark found that sound from acoustic road markings did not alter fallow deer behaviour. A controlled study in Australia found that Roo-Guard® sound emitters did not deter tammar wallabies from food and so were not considered suitable for keeping them off roads. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2592https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2592Thu, 11 Jun 2020 13:09:39 +0100Collected Evidence: Collected Evidence: Fit vehicles with ultrasonic warning devices Three studies evaluated the effects on mammals of fitting vehicles with ultrasonic warning devices. Two studies were in the USA and one was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): A replicated, controlled study in Australia found that Shu Roo warning whistles did not reduce animal-vehicle collisions for eastern grey kangaroos or red kangaroos BEHAVIOUR (3 STUDIES) Behaviour change (3 studies): Three controlled studies (two replicated), in the USA and Australia, found that ultrasonic warning devices did not deter mule deer, eastern grey kangaroos, red kangaroos or white-tailed deer from roads. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2606https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2606Thu, 11 Jun 2020 15:50:34 +0100Collected Evidence: Collected Evidence: Close roads in defined seasons One study evaluated the effects on mammals of closing roads in defined seasons. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (1 STUDY) Use (1 study): A site comparison study in the USA found that closing roads to traffic during the hunting season increased use of those areas by mule deer. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2626https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2626Fri, 12 Jun 2020 11:07:53 +0100
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What Works in Conservation

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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