Edward O. Guerrant

Reintroduction of rare and endangered plants: common factors, questions and approaches

The science of reintroduction for conservation purposes is young, and there is still much to learn about the practice. As a means to achieving biological goals of successfully establishing new populations to enhance a species survival prospects, and project goals, such as learning how to go about establishing new populations, reintroduction projects are best done as well designed scientific experiments that test explicit hypotheses. Focusing on a range of factors common to any reintroduction, we review several empirical reintroduction projects with respect to hypotheses tested, experimental materials and methods employed, and evaluate their success in both biological and project terms.

Flower defenses against nectar-pilferage by ants

ro determine palatability, floral nectars from 25, and floral tissue extracts from 17, plant species of wet and dry forests of Costa Rica were offered to foraging ants in pairwise tests with sugar solutions. Nectars from all 25, and floral tissues from 10, species were analyzed chemically to ascertain the presence of potentially attractive and deterrent substances. In general, floral nectars are palatable to ants, whereas floral tissues showed highly variable palatability. We observed ants foraging in flowers of only 10 species of plants. Defense from nectar thievery by chewing insects seems most often to involve varying degrees of chemical and morphological modification of floral parts, rather than by the production of deterrent compounds in the nectar itself. FLOWERS THAT OFFER NECTAR as a primary reward to pollinators are common in the tropics. Nectar is generally nutritious and energy-rich, and pollination and seed set regularly occur as a result of the nectargathering activities by a wide array of animals, including many hymenoptera. Ants, however, are only rarely considered reliable pollinators (Kerner von Marilaun 1878, Proctor and Yeo 1972, Hickman 1974, Faegri and van der Pijl 1979), even though they are extremely abundant in a wide variety of habitats and are notorious for their skill in locating even small amounts of sugar. It is surprising that observations in the tropics reveal ants foraging for nectar in flowers only occasionally (van der Pijl

Heterochrony in Plants

Phylogenetic changes in ontogenetic rates or timing are termed heterochrony. Evolutionary changes in organismal form necessarily arise from alterations in ontogenies, and so it is hardly surprising that heterochrony has profoundly affected the evolution of plants as well as animals. However, because the life cycles, body plans, and growth of plants and animals are so different, the effects of heterochrony are expressed differently in plants than they are in animals. The indeterminate or open growth habit and modular construction of plants lead to much greater environmentally induced phenotypic variation in form than is found in animals. Consequently, even though zoocentric theory has much to offer botanists, the study of heterochrony in plants must take on a character of its own.Phylogenetic changes in ontogenetic rates or timing are termed heterochrony. Evolutionary changes in organismal form necessarily arise from alterations in ontogenies, and so it is hardly surprising that heterochrony has profoundly affected the evolution of plants as well as animals. However, because the life cycles, body plans, and growth of plants and animals are so different, the effects of heterochrony are expressed differently in plants than they are in animals. The indeterminate or open growth habit and modular construction of plants lead to much greater environmentally induced phenotypic variation in form than is found in animals. Consequently, even though zoocentric theory has much to offer botanists, the study of heterochrony in plants must take on a character of its own.

Characterizing Two Decades of Rare Plant Reintroductions

There is enormous potential conservation value in the ability to establish new populations of rare plants. When combined with ex situ source material, reintroduction offers valuable and otherwise unavailable conservation options. Indeed, reintroduction of material stored ex situ has made the difference between extinction in the wild and continued survival.

Synthesis and Future Directions

Reintroduction work must continue and should be expanded because it is an important tool to stabilize and restore vulnerable declining species. Reintroduction can play a vital role in keeping species present in our landscape through climate change, but this will be possible only through careful planning, research, modeling, and priority setting. In this chapter we review the insights emerging from the sections of this volume: the meta-analyses of plant reintroductions, the science and practice of reintroduction, and managed relocation (MR). We provide examples of well-conceived reintroduction projects to serve as models for planning future reintroductions. Furthermore, we make suggestions for improving plant rein-troduction science and practice, preparing for climate change, and moving forward to best conserve biodiversity.