Ecological Effects of Roads Landscape Ecology

Comments/Questions

Effects of roads Mortality from road construction Mortality from collisions Modify behavior Disrupt physical environment Alter chemical environment Spread of exotic species Changes in human use

Mortality from construction In U.S.: ◦ 13.1 million km of roads ◦ 4.7 million ha of land.

Mortality from collisions Primary cause of death of moose in Kenai NWR Amphibians especially vulnerable. Mitigaion: ◦ Construction of underpasses -  Has reduced roadkill of Florida panther.

Factors influencing wolf Canis lupus roadkills in Northwest Spain Author(s): Colino-Rabanal, et al. Source: EUROPEAN JOURNAL OF WILDLIFE RESEARCH: 57 JUN 2011

Statistical Model - logistic

Results Traffic measures are important.

Modify Animal Behavior Changes in home ranges ◦ Avoiding roads Changes in movement ◦ Facilitates movement ◦ Impedes movement Changes in nesting location Most examples are about populations – what about communities?

Forest bird communities across a gradient of urban development Author(s): Minor, Emily; Urban, Dean Source: Urban Ecosystems Volume: 13 MAR 2010 Questions: ◦ (1) does community composition of forest birds change across a gradient of urban development, ◦ (2) if so, what are the important variables driving these changes,

Forest bird communities across a gradient of urban development Author(s): Minor, Emily; Urban, Dean Source: Urban Ecosystems Volume: 13 MAR 2010 Results: ◦ (1) does community composition of forest birds change across a gradient of urban development, Yes ◦ (2) if so, what are the important variables driving these changes, Forest, Urban and Road Density.

Disruption of Physical Environment Soil Compaction Increased surface temperature ◦ Aggregation of snakes Spread of dust ◦ Reduces photosynthesis Change hydrology ◦ Surface water ◦ Groundwater

Flow in culverts as a potential mechanism of stream fragmentation for native and nonindigenous crayfish species Author(s): Foster, HR & Keller, TA Source: JNABS Volume: 30 DEC ) culverts elevate flow velocities compared to upstream riffle segments, 2) crayfish have more difficulty moving upstream in culverts with elevated flows, 3) the nonindigenous O. rusticus is more successful in moving upstream through culverts than the native O. propinquus or O. virilis, and 4) higher flow velocities are needed to impede the upstream movement of O. rusticus than its congeners.

How to test? 1) culverts elevate flow velocities compared to upstream riffle segments, 2) crayfish have more difficulty moving upstream in culverts with elevated flows,

Velocity

Results 1) culverts elevate flow velocities compared to upstream riffle segments, Yes 2) crayfish have more difficulty moving upstream in culverts with elevated flows, Yes, they slip more.

Alteration of Chemical Env. Increased heavy metals Increased salts Production of ozone

Toxicity of road salt to Nova Scotia amphibians Author(s): Collins, SJ & Russell, RW Source: ENVIRONMENTAL POLLUTION Volume: 157 JAN 2009 Objective: ◦ examine how chloride concentrations in ponds, due to application of road salt, influence amphibian community structure and richness in roadside wetlands of Nova Scotia.

Methods From April through September, 2006, 26 ponds within 60 m of secondary roads or highways were sampled for the presence of amphibian species. Ponds were selected on the basis that they could potentially receive road runoff. All ponds were within 50 m of a mature woodlot of at least 0.5 ha. Presence was determined if any life stage was detected at a pond.

Results Species richness decreased with increasing chloride concentrations. Spotted salamanders and wood frogs were the most sensitive amphibian species to elevated Cl concentrations. ◦ These two species were the earliest breeding species, thus most susceptible to spring runoff of saline water, and consequently were absent from ponds with elevated chloride concentrations

Spread of Exotic Species Intentional introductions ◦ Erosion control ◦ Ease of access – Fish stocking Vector of transport

Human Use Changes Increased use by people Poaching Decline in streams

Forest Elephant Crisis in the Congo Basin Authors: Blake S, et al. Source: PLoS Biol 5(4) 2007 Our goals were to evaluate the conservation status of forest elephants, including population size, distribution, and levels of illegal killing in relation to human activity, isolation from roads, and the impact of protected areas.

Results: Our results indicate that a combination of illegal killing and other human disturbance has had a profound impact on forest elephant abundance and distribution, including inside national parks (NPs). a significant positive relationship between the probability of presence of elephants and increasing distance from the nearest major road the probability of human presence decreased with increasing distance from the nearest road, in contrast to the probability of elephant occurrence