| Tonner Canyon and its Significance to the Puente/Chino Hills Wildlife Corridor |
| Introduction to the Issue
Scenic Tonner Canyon, straddling both Los Angeles and Orange Counties, represents one of the most critical land use issues in Southern California. Located in the Puente/Chino Hills complex (referred to as the �Corridor�), it is a collection of endangered ecosystems, a thriving mosaic of wildlife habitats, a crucial wildlife corridor, and a place where generations of people have learned about the natural world. This paper will seek to examine the concepts of a wildlife corridor and how they apply to these hills, what benefits this corridor has to wildlife and to humans, and why Tonner Canyon is so crucial to the success of the Corridor. This last topic will explore why recent ownership changes of Tonner Canyon have given rise to concern for its future, and what will happen if the property is developed, both to the canyon itself and to the entire Corridor system. The term �wildlife corridor� has a double meaning in the case of these hills, which can be confusing. The traditional corridor concept of a relatively narrow strip of land (squeezed by development) joining two larger habitat areas certainly applies at several key sections of the hills where urbanization has encroached particularly far into the hillsides, and will be addressed in this paper. This concept has been explored by numerous studies and literature from various habitats of the world. However, the entire range of the Puente/Chino Hills is also referred to as a wildlife Corridor (Puente Hills Landfill Native Habitat Preservation Authority, pdf/pg1-12v2b.pdf). This is because these hills are long and narrow compared to the surrounding sea of urban development, and in this sense function as a corridor in which animals and plants can move back and forth between the Santa Ana Mountains and the Whittier Hills. Here, a corridor is not just a connection between larger habitats, but a whole system of connected habitats, dependent upon each other for support and resources. The biological diversity and ecological health of each section is dependant upon all of the other sections to maintain the species that live there. This latter concept of a corridor is the main justification of preserving these hills, since they are an interwoven collection of ecosystems that allows for a host of native species to survive and remain genetically viable and healthy. It is this idea of a Corridor that will be a main focus of this paper, specifically addressing why development in Tonner Canyon can prove so detrimental to the ecological future of the entire region. Both of the above mentioned concepts of a wildlife corridor apply in these hills, making for an interesting study in human and wildlife interactions and natural resource planning, and both will now be examined individually to understand how they shape the future of the Puente/Chino Hills wildlife Corridor. 1. Traditional Corridor Concept The traditional concept of a wildlife corridor is becoming increasingly important, and utilized, in our efforts to preserve the biological diversity of our remaining natural areas. This type of corridor can be defined as �a linear habitat, embedded in a dissimilar matrix, that connects two or more larger blocks of habitat and that is proposed for conservation on the grounds that it will enhance or maintain the viability of specific wildlife populations in the habitat blocks� (Beier and Noss, 1998, 1242). This paper was interesting because it was an analysis of previous corridor-related studies, and was seeking to address whether animals used the corridors as avenues of movement. While conceding that since most studies focus upon a single species or habitat area, making generalizations about corridors that can be uniformly applied to all situations is unrealistic. It was concluded that there is, however, enough evidence to believe that corridors do provide a conservation benefit, and that many native animals did use them to travel from area to area (Beier and Noss, 1998, 1249). Why is it so important for animals (and plants) to be able to travel from one habitat area to another? One main reason is the need to have a continuing influx of genes into the population, with isolated groups eventually suffering from inbreeding and local extinctions. The influx of new animals into a population gives a fresh combination of genes, and links between habitats provide the avenues by which that can occur (Noss, Beier and Shaw, 2002, 3). A study of voles and mice using clear cuts among the forests as impediments to travel between areas, and strips of trees as �corridors� found that �one of the benefits of maintaining corridors is an increase in gene flow between populations, which may result in an increase in population persistence and a decrease in inbreeding�(Mech and Hallett, 2001, 473). Also, animals need to travel to new areas in search of food and shelter, and corridors enable that to happen. I feel that the definition of corridor that they used, as linking �two or more patches of wildlife (animal) habitat that have been connected in historical time� (Mech and Hallett, 2001, 468) sums up this entire concept, that we are simply trying to maintain an ecological connection that has existed for many generation before human interference reduced it to its current tenuous state. |