Translocation success in Iris atrofusca: importance of replicating sites and long‐term monitoring

Abstract

Translocation gains importance as a conservation approach of choice for imperiled plant species whose habitat is rapidly disappearing. To be successful, translocation must be done into a location that has optimal conditions for the species, but determining these conditions can be difficult for species with poorly known historic distribution. Unfortunately, most endangered plant species, including those requiring immediate action, have poorly documented historic ranges. In this study, we show, using the threatened rhizomatous Iris atrofusca, that the determination of suitable locations should be done experimentally over multiple locations, and the evidence for the success of translocation comes not just from the establishment of the planted individuals or their reproduction, but, more importantly, from the appearance, establishment and reproduction of recruits. Although 12 years after introduction, 2 of the 22 populations went extinct and the number of survived plants was below 10% in 12 populations, 4 established recruits were detected outside the planted areas in that year and another 48 individuals 2 years later. We conclude that locations in the immediate vicinity of recruits should be used for actual translocation. We also report, after analyzing the effect of four environmental variables on I. atrofusca performance across experimental microsites, the most favorable set of topographic and soil parameters for this species, namely deep soil having few rock fragments and minor slope steepness. Microsites with these parameters should be the preferred locations for I. atrofusca introduction. Overall, our study demonstrates the importance of (1) experiments preceding actual translocation and (2) long-term monitoring for translocation projects.

Habitat Selection to Reintroduce Iris bismarckiana in Semi-Arid Environments

“…The major pollinators of I. bismarckiana are solitary male bees of Eucera spp. (Apidae family) [13]. In Dibbeen Forest Reserve, only Apis, Bombus, and Melecta genera were recorded from the Apidae family [25].…”

“…Plant conservation protocols can be in situ, ex situ conservation, or reintroduction of species of interest [1,12]. Plant conservation involves two essential strategies: translocation or introduction [13]. Translocation conservation refers to the purposeful relocation of plant species from one location to another aiming to generate conservation advantages at population, species, or ecosystem levels [14].…”

“…However, the introduction conservation strategy involves facilitating colonization and ecological replacement outside the species' native range [14]. The introduction activities can be implemented away from the current range, or in an adjacent area near the existing range [13]. The main principles of reintroduction are (1) augmentation or enhancement (e.g., of plant species) by increasing the population size, and (2) restitution or restoration of a species by releasing the individuals of a species into an area it was formerly inhabiting [1].…”

“…Several studies have executed reintroduction programs of rare plants (including bulbous and rhizomatous ones) to new sites that share similar levels of different variables. These variables included soil edaphic factors (pH, electrical conductivity, depth, percent of rock fragment by volume of soil, texture, respiration rate), soil microbial abundance and activity (e.g., mycorrhizae), site topography (slope degree), vegetation cover, climatic conditions (e.g., rainfall, radiation, and temperatures), reproductive biology, pollinators, protection status, and land use/cover information [13,[17][18][19].…”

Assessing Population Genetic Status for Designing Plant Translocations

“…However, translocation-based population restoration may fail for several reasons. Poor habitat conditions have been reported as a determinant factor in failure, resulting in high mortality of transplants and low recruit establishment (Godefroid et al, 2011;Schäfer et al, 2020;Volis and Blecher, 2021). Other studies found high inbreeding levels in transplants or in their offspring as a result of a low number of genotypes or reduced pollination service in source populations (Krauss et al, 2002;Monks et al, 2021;Van Rossum and Le Pajolec, 2021).…”