17. Influences of shelterbelts on wildlife management and biology

Abstract

Shelterbelts provide benefits to wildlife in several ways, including protection from wind and adverse weather, escape or refuge cover, food and foraging sites, reproductive habitat and travel corridors. At least 108 species of birds and 28 species of mammals are known to use shelterbelt habitats. In agricultural areas, 29 species of birds, benefit substantially, 37 moderately and 42 very little or accidentally. At least 57 species of birds have been recorded using shelterbelts during the breeding season and, of these, 28 are known to have nested in them at densities from about 0.3–186 nests ha −1. Shelterbelts have helped maintain or extend the ranges of several small mammal and bird species. For enhancement of wildlife benefits, shelterbelts should be designed to provide the needs of the wildlife most desired and be of sufficient size and complexity to provide wildlife needs throughout the year, including winter food and weather protection appropriate for local climatic conditions. Numbers and diversity of wildlife are usually positively correlated with shelterbelt area and length of perimeter, diversity of vegetation and vegetation complexity. Variation in type of vegetation (e.g. several species of deciduous and coniferous trees, shrubs, grasses, and forbs), in addition to well-developed canopy and understory layers, are desirable. Snags provide nesting and foraging sites for many species; management options include topping snags to leave 4–5-m stumps and providing nest boxes. Overgrazing seriously degrades the benefits of shelterbelts to wildlife, particularly for species that utilize the understory layer. Shelterbelts provide only a portion of most wildlife needs, and thus should be viewed in relation to other nearby resources so that all needs of desired wildlife are met. Adjacent food resources are of particular importance to some wildlife species. Wildlife associated with shelterbelts may provide economic, educational, recreational and aesthetic benefits. In contrast, some species may cause damage or nuisance problems in adjacent areas. Overall, these problems are minor/or can be controlled. Relationships among wildlife, shelterbelts and people are not well studied, so numerous research opportunities and needs exist.