The reintroduction of plants will become an increasingly utilized strategy in plant conservation and protected area management. Reintroduction is the deliberate establishment of individuals of a species into an area and/or habitat where it has become extirpated with the specific aim of establishing a viable self-sustaining population for conservation purposes. Plant reintroduction can involve the establishment of an extirpated species into a relatively intact habitat or it can be part of the restoration of a degraded habitat. This will be performed as species become extinct for a number of reasons, such as collecting, introduced herbivores or pathogens and potentially climate change. Although plant reintroductions have the potential to play an important role in species' conservation the long term viability of many reintroductions has yet to be assessed. For the technique to reach it's full potential it requires greater integration with habitat management, restoration and increased international coordination between both theex situ andin situ agencies. In addition the value of introducing stocks of endangered species lacking viable sites for reintroduction to non native sites is discussed.

Plant reintroduction: an overview

Summary


1
 Positive relationships between the density and distribution of species in taxonomic assemblages are well documented, but the underlying mechanisms remain poorly understood. Two factors that are expected to be important in explaining variation in these relationships are the spatial scale of analysis and the relative mobility of the study species.

2
 We examined density–distribution relationships in British butterflies at a variety of spatial scales. Distributions were proportions of grid squares occupied: 50 m grid within 0·25 km2 areas (local), 500 m grid in 35 km2 (regional), 10 km grid across England, Wales and Scotland (national), 153 000 km2 grid squares across Europe (European), and also seven categories of international distribution (Global; 1 = European endemic to 7 = in 5 + continents). Densities were measured using transect counts at local, regional and national scales.

3
 Different relationships between density and distribution occurred at different scales of analysis. When we controlled for the effects of mobility and/or phylogenetic association, a positive relationship between density and distribution was apparent at local, regional and national scales. Species’ national densities in Britain were positively correlated with their European distribution sizes, but significantly negatively correlated with their global range sizes.

4
 Butterfly mobility had a positive effect on distribution and a negative effect on density at all spatial scales. For a given total abundance, more mobile species had lower densities but wider distributions, i.e. they were less aggregated than more sedentary species.

5
 The decreasing strength of the density–distribution correlation, and the eventual reversal of the pattern, with the increasing magnitude of difference between the scale at which density was measured relative to distribution, suggests that some element of niche may be important in determining densities and distributions. However, the measure of niche breadth analysed did not explain significant variation in density, distribution, or in the density–distribution relationship.

Density–distribution relationships in British butterflies. I. The effect of mobility and spatial scale

Rarity, species richness and conservation: Butterflies of the Atlas Mountains in Morocco

The challenge of conserving grassland insects at the margins of their range in Europe

Ex situ seed conservation aims to support species survival in the wild. This can be achieved by contributing genetic material for reintroduction. The goals of reintroduction are to increase both plant and population numbers, create self-sustaining populations and ultimately remove a species from its threatened listing. Quality seed collections with a broad genetic base are required to achieve this goal. Storage conditions that minimise deterioration of seeds will maximise the quality of seeds available for future use. Additionally, ex situ seed conservation provides long-term insurance against species or genotype loss until actual or potential threats can be removed. As threats to biodiversity escalate the most judicious conservation strategies will be ones that combine available resources to provide the highest possible degree of protection. Banked seeds are available irrespective of season and periods of low fecundity. Forward planning of reintroduction projects can be achieved with knowledge of the quantity and quality of banked seed. This paper discusses the challenges facing ex situ seed conservation while highlighting the benefits of integrating ex situ seed storage and plant reintroduction to help provide for better conservation outcomes.

J.E. Hernandez-Bermejo

Papers

Experimental reintroductions of endangered plant species in their natural habitats in Spain