Benefits of Conservation of Plant Genetic Diversity to Arthropod Diversity

Abstract:  We argue that the genetic diversity of a dominant plant is important to the associated dependent community because dependent species such as herbivores are restricted to a subset of genotypes in the host-plant population. For plants that function as habitat, we predicted that greater genetic diversity in the plant population would be associated with greater diversity in the dependent arthropod community. Using naturally hybridizing cottonwoods (  Populus spp.) in western North America as a model system, we tested the general hypothesis that arthropod alpha (within cross-type richness) and beta (among cross-type composition) diversities are correlated with cottonwood cross types from local to regional scales. In common garden experiments and field surveys, leaf-modifying arthropod richness was significantly greater on either the F₁ (1.54 times) or backcross (1.46 times) hybrid cross types than on the pure broadleaf cross type (  P. deltoides Marshall or P. fremontii Watson). Composition was significantly different among three cross types of cottonwoods at all scales. Within a river system, cottonwood hybrid zones had 1.49 times greater richness than the broadleaf zone, and community composition was significantly different between each parental zone and the hybrid zone, demonstrating a hierarchical concentration of diversity. Overall, the habitats with the highest cottonwood cross-type diversity also had the highest arthropod diversity. These data show that the genetics of habitat is an important conservation concept and should be a component of conservation theory.     

Tropical Diversity and Conservation

The superior diversity of the tropics is well known and, for the largest marine and continental areas, there appears to be a positive relationship between area and species diversity (richness). There are certain portions of the tropics, however, in which species diversity has reached unusually high levels. Such areas apparently function as centers of evolutionary origin. In the ocean the largest of the four tropical shelf regions is the Indo-West Pacific, which stretches almost two thirds of the distance around the globe. Within that expanse by far the greatest diversity is found within the relatively small East Indies Triangle. From the Triangle an evolutionary radiation has reached many other parts of the marine world. On land the Neotropical, Ethiopian, and Oriental biogeographic regions demonstrate very high levels of species diversity. Various major groups of animals and plants have originated in these regions and subsequently spread to other parts of the world. There is no accepted scientific agreement on a conservation strategy for these areas. By focusing our attention on centers of origin, we can save the areas containing species that apparently have the greatest evolutionary potential.     

Diversity in industrial ecosystems

Within the natural world, diversity refers to the variety and variability among living organisms and the ecological complexes in which they occur. Its complexity is measured in terms of variations at genetic, species and ecosystem levels. It plays a critical role in meeting human needs while maintaining the ecological processes upon which our survival depends. This paper agues that such a natural metaphor should be considered in industrial systems in order to realise sustainable development. This article begins by describing natural biodiversity, emphasising its definition and value, and its maintenance. Next, the paper discusses the rationale and mechanisms for encouraging industrial diversity. The authors suggest that this natural metaphor provides a useful guide on how businesses in an industrial system can evolve towards greater resilience and sustainability.     

The Prairie Dog and Biotic Diversity

Since the turn of this century, prairie dog populations have declined as much as 98% throughout North America, largely as a result of prairie dog eradication programs. The prairie dog is a keystone species that plays an important role in maintaining the biotic integrity of the western grasslands that stretch from southern Canada to northern Mexico. The fragmentation of prairie dog distribution has degraded diversity on those prairies, and several species depending on prairie dogs have achieved listing status under the Endangered Species Act. We propose that managing the praire dog would provide an effective avenue from single-species management to management of a system. Because prairie dogs have declined so profoundly, some form of legal protection will be required. In addition, protected areas can preserve habitat and integrate ecologically sound agricultural opportunities. Positive incentives for ranchers to manage in the interests of both livestock and wildlife will enhance the attitude change necessary for grassland conservation. These management options hinge critically on an end to U.S. government subsidies for prairie dog eradication programs. The subsidies are financially and ecologically unsound, and they only contribute to the prevailing misconceptions about the role of the prairie dog on the grasslands.     

中新天津生态城植物多样性分析

2008年对中新天津生态城规划区域植被进行调查,发现该区域以盐生植被为主,现存植被可分为4个类型15种植物群落;植物区系成分含38科101属135种。本区植被的分布受土壤盐碱度的制约,并受当代人为因素的严重影响,盐生植物资源丰富,其中26种耐盐植物具有较大开发利用价值。因此,建议采取保留与保护现存的盐生植被;利用耐盐植物进行盐碱地绿化及研究和发展本区盐碱地环境的生态管理。