Insect conservation in Michigan prairie fen: addressing the challenge of global change

Prairie fen is a globally rare, groundwater dependent peatland community restricted to discrete portions of the glaciated north central USA. Prairie fen harbours a diverse flora composed of sedge wetland and tallgrass prairie species, which in turn support a diversity of rare insects. In Michigan, USA over 20% of the state’s insects of conservation concern are associated with prairie fen, including the globally imperilled Mitchell’s satyr butterfly, Neonympha mitchellii mitchellii (Lepidoptera: Nymphalidae). Here we investigate how global change drivers, including land use change, climate change, and invasive species, may interact to threaten this important community. Specifically, we examine how characteristics of prairie fen habitats—e.g., formation and distribution—interact with the biology of rare fen insects to suggest appropriate short to long term conservation strategies. Our results suggest that prairie fen associated insects are rare for a variety of reasons, including host plant specialization, habitat specialization, and shifting landscape context that limits opportunities for dispersal. We recommend that current conservation efforts focus on stabilization and restoration of existing prairie fens, coupled with directed surveys to monitor population change in insects of concern, and restoration of the landscape matrix to facilitate metapopulation dynamics. In the future, due to the severely fragmented nature of Michigan landscapes, captive rearing and assisted migration may be necessary to conserve some prairie fen insect species. Overall, the effective conservation of fen associated insects will require a shared vision by multiple actors and a willingness to purse that vision over a long time frame.     

Important Plant Areas: revised selection criteria for a global approach to plant conservation

Despite the severe threats to plant habitats and high levels of extinction risk for plant species in many parts of the world, plant conservation priorities are often poorly represented in national and global frameworks because of a lack of data in an accessible and consistent format to inform conservation decision making. The Important Plant Areas (IPAs) criteria system offers a pragmatic yet scientifically rigorous means of delivering these datasets, enabling informed national- or regional-scale conservation prioritisation, and contributing significantly towards global prioritisation systems including the International Union for Conservation of Nature Key Biodiversity Areas (KBAs) Standard. In this paper, we review the IPA rationale and progress on IPA identification to date, including the perceived limitations of the process and how these may be overcome. We then present a revised set of criteria for use globally, developed through the combined experiences of IPA identification over the past decade and a half and through a recent global consultation process. An overview of how the revised IPA criteria can work alongside the newly published KBA Standard is also provided. IPA criteria are based around a sound, scientific, global framework which acknowledges the practical problems of gathering plant and habitat data in many regions of the world, and recognises the role of peer reviewed expert opinion in the selection process. National and sub-national engagement in IPA identification is essential, providing a primary route towards long term conservation of key sites for plant diversity. The IPA criteria can be applied to the conservation of all organism groups within the plant and fungal kingdoms.     

Contrasting demographic and genetic estimates of dispersal in the endangered Coahuilan box turtle: a contemporary approach to conservation

The evolutionary viability of an endangered species depends upon gene flow among subpopulations and the degree of habitat patch connectivity. Contrasting population connectivity over ecological and evolutionary timescales may provide novel insight into what maintains genetic diversity within threatened species. We employed this integrative approach to evaluating dispersal in the critically endangered Coahuilan box turtle (Terrapene coahuila) that inhabits isolated wetlands in the desert‐spring ecosystem of Cuatro Ciénegas, Mexico. Recent wetland habitat loss has altered the spatial distribution and connectivity of habitat patches; and we therefore predicted that T. coahuila would exhibit limited movement relative to estimates of historic gene flow. To evaluate contemporary dispersal patterns, we employed mark–recapture techniques at both local (wetland complex) and regional (intercomplex) spatial scales. Gene flow estimates were obtained by surveying genetic variation at nine microsatellite loci in seven subpopulations located across the species’ geographical range. The mark–recapture results at the local spatial scale reveal frequent movement among wetlands that was unaffected by interwetland distance. At the regional spatial scale, dispersal events were relatively less frequent between wetland complexes. The complementary analysis of population genetic substructure indicates strong historic gene flow (global F_ST = 0.01). However, a relationship of genetic isolation by distance across the geographical range suggests that dispersal limitation exists at the regional scale. Our approach of contrasting direct and indirect estimates of dispersal at multiple spatial scales in T. coahuila conveys a sustainable evolutionary trajectory of the species pending preservation of threatened wetland habitats and a range‐wide network of corridors.     

Assessing the relative importance of dispersal in plant communities using an ecoinformatics approach

Increased insight into the factors that determine the importance of dispersal limitation on species richness and species composition is of paramount importance for conservation and restoration ecology. One way to explore the importance of dispersal limitation is to use seed-sowing experiments, but these do not enable the screening of large sets of species and habitats. In the present paper we present a complementary approach based on comparing small plots with larger regions with regard to species composition and distribution of functional traits. We developed a GIS tool based on ecological and geographical criteria to quantify species pools at various spatial scales. In this GIS tool, containing floristic, large databases, phytosociological and functional information are exploited. Our premise is that differences in the nature of the species in local and regional species pools with regard to functional traits can give important clues to the processes at work in the assembly of communities. We illustrate the approach with a case study for mesotrophic hay meadows (Calthion palustris). We tested the effects of differences in frequency in the local Habitat Species Pool and differences in dispersal and persistence traits of species on local species composition. Our results show that both species pool effects and functional traits affect the probability of occurrence in small plots. Species with a high propagule weight have, given the frequency in the Local Habitat Species Pool, a lower probability of occurrence in small plots. The probability of local occurrence, however, is increased by the ability to form a persistent soil seed bank and by adult longevity. This provides support for the view that the degree of dispersal limitation is dependent on the degree of spatial isolation of the focal site relative to source populations and moreover that species inherently differ in the degree to which dispersal limitation is a limiting factor for local occurrence.     

Postnatal dispersal of wandering albatrosses Diomedea exulans: implications for the conservation of the species

Many large marine vertebrates are today threatened by human activities and it is therefore crucial to obtain information on their distribution and behaviour at sea. In particular little is known about the time necessary for juveniles to acquire the foraging skills of adults. We tracked 13 juvenile wandering albatrosses Diomedea exulans by satellite telemetry during their first year at sea. They covered an average distance of 184,000 km during the first year and restricted their dispersal to the unproductive waters of the subtropical Indian Ocean and Tasman Sea. This region of low wind velocities does not overlap with the foraging areas used by adults. After an innate phase of rapid dispersal with a fixed flight direction, young birds progressively increased their daily flight distances and attained adult flight efficiency within their first six months at sea. The complete overlap of the juveniles' foraging ranges with major long-line fisheries in the subtropical waters constitutes a major threat that could jeopardize the long term recovery ability of populations of the endangered wandering albatross in the Indian Ocean.     

Postnatal dispersal of wandering albatrosses Diomedea exulans: implications for the conservation of the species

Many large marine vertebrates are today threatened by human activities and it is therefore crucial to obtain information on their distribution and behaviour at sea. In particular little is known about the time necessary for juveniles to acquire the foraging skills of adults. We tracked 13 juvenile wandering albatrosses Diomedea exulans by satellite telemetry during their first year at sea. They covered an average distance of 184,000 km during the first year and restricted their dispersal to the unproductive waters of the subtropical Indian Ocean and Tasman Sea. This region of low wind velocities does not overlap with the foraging areas used by adults. After an innate phase of rapid dispersal with a fixed flight direction, young birds progressively increased their daily flight distances and attained adult flight efficiency within their first six months at sea. The complete overlap of the juveniles’ foraging ranges with major long‐line fisheries in the subtropical waters constitutes a major threat that could jeopardize the long term recovery ability of populations of the endangered wandering albatross in the Indian Ocean.     

Sex-biased dispersal in a rare butterfly and the implications for its conservation

The survival of many species may be dependent on their ability to exist in human-altered landscapes within metapopulations; in turn, metapopulation persistence is dictated by the ability of individuals to move effectively among patches to promote recolonization. The Taylor’s checkerspot butterfly (Euphydryas editha taylori) is a species that does not naturally occur in fragmented landscapes, yet it is now restricted to a handful of small isolated prairie habitats. Current recovery plans aim to establish a stable metapopulation; however, to date little is known about the species’ ability to move across the landscape. In 2010 and 2011, we conducted marking, tracking and boundary surveys to explore the movement dynamics of adults within two sites in Oregon, USA. Over the survey period, we marked 136 male butterflies, tracked 174 individuals and observed the behavior of 1,576 individual butterflies at site boundaries. Our study revealed a significant sex-bias in the movement dynamics of the Taylor’s checkerspot in both suitable habitat and surrounding matrix. Males were highly motile, whereas females appeared sedentary, rarely moving from their natal site. The limited dispersal behavior of females indicates that populations cannot persist naturally in a metapopulation and thus are at high risk of extinction. Based on our findings, we recommend that managers take proactive measures to increase or enable dispersal (including translocation) to existing and/or restored sites.     

Contrasting success in the restoration of plant and phytophagous beetle assemblages of species-rich mesotrophic grasslands

Over the last 60 years changes to the management of species-rich mesotrophic grasslands have resulted in the large-scale loss and degradation of this habitat across Europe. Restoration of such grasslands on agriculturally improved pastures provides a potentially valuable approach to the conservation of these threatened areas. Over a four-year period a replicated block design was used to test the effects of seed addition (green hay spreading and brush harvest collection) and soil disturbance on the restoration of phytophagous beetle and plant communities. Patterns of increasing restoration success, particularly where hay spreading and soil disturbance were used in combination, were identified for the phytophagous beetles. In the case of the plants, however, initial differences in restoration success in response to these same treatments were not followed by subsequent temporal changes in plant community similarity to target mesotrophic grassland. It is possible that the long-term consequences of the management treatments would not be the establishment of beetle and plant communities characteristic of the targets for restoration. Restoration management to enhance plant establishment using hay spreading and soil disturbance techniques would, however, still increase community similarity in both taxa to that of species-rich mesotrophic grasslands, and so raise their conservation value. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Use of biotechnologies for the conservation of plant biodiversity

In vitro techniques are very useful for conserving plant biodiversity, including (a) genetic resources of recalcitrant seed and vegetatively propagated species, (b) rare and endangered plant species and (c) biotechnology products such as elite genotypes and genetically engineered material. Explants from recalcitrant seed and vegetatively propagated species can be efficiently collected under field conditions using in vitro techniques. In vitro culture techniques ensure the production and rapid multiplication of disease-free material. Medium-term conservation is achieved by reducing growth of plant material, thus increasing intervals between subcultures. For long-term conservation, cryopreservation (liquid nitrogen, −196°C) allows storing plant material without modification or alteration for extended periods, protected from contaminations and with limited maintenance. Slow growth storage protocols are routinely employed for a large number of species, including numerous endangered plants, from temperate and tropical origin. Cryopreservation is well advanced for vegetatively propagated species, and techniques are ready for large-scale experimentation in an increasing number of cases. Research is much less advanced for recalcitrant species due to their seed characteristics, viz., very high sensitivity to desiccation, structural complexity and heterogeneity in terms of developmental stage and water content at maturity. However, various technical approaches should be explored to develop cryopreservation techniques for a larger number of recalcitrant seed species. A range of analytical techniques are available, which allow understanding physical and biological processes taking place in explants during cryopreservation. These techniques are extremely useful to assist in the development of cryopreservation protocols. In comparison with crop species, only limited research has been performed on cryopreservation of rare and endangered species. Even though routine use of cryopreservation is still limited, an increasing number of examples where cryopreservation is used on a large scale can be found both in genebanks for crops and in botanical gardens for endangered species.     

Flow regulation affects temporal patterns of riverine plant seed dispersal: potential implications for plant recruitment

1. Changes to the natural flow regime of a river caused by flow regulation may affect waterborne seed dispersal (hydrochory), and this may be an important mechanism by which regulation affects riverine plant communities. We assessed the effect of altered timing of seasonal flow peaks on hydrochory and considered the potential implications for plant recruitment. 2. We sampled hydrochory within five lowland rivers of temperate Australia, three of which are regulated by large dams. These dams are operated to store winter and spring rains and release water in summer and autumn for agriculture. At three sites on each river, hydrochory was sampled monthly for 12 months using passive drift nets. The contents of the drift samples were determined using the seedling‐emergence method. 3. More than 33 000 seedlings from 142 taxa germinated from the samples. In general, more seeds and taxa were observed in the drift at higher flows. By altering the period of peak flows from winter–spring to summer–autumn, flow regulation similarly affected the period of peak seed dispersal. The effect of regulation on seed dispersal varied between taxa depending on their timing of seed release and whether or not they maintain a persistent soil seed bank. 4. Hydrochory in rivers is a product of flow regime and the life history of plants. By altering natural flow regimes and thus hydrochorous dispersal patterns, flow regulation is likely to affect adversely the recruitment of native plant species with dispersal phenologies adapted to natural flow regimes (such as many riparian trees and shrubs) and encourage the spread of non‐native (exotic) species. 5. Changes to hydrochorous dispersal patterns are an important mechanism by which altered flow timing affects riverine plant communities. Natural seasonal flow peaks (in this case spring) are likely to be important for the recruitment of many native riparian woody taxa.     

Consequences of large-scale processes for the conservation of bird populations

1.  Detailed studies of population ecology are usually carried out in relatively restricted areas in which emigration and immigration play a role. We used a modelling approach to explore the population consequences of such dispersal and applied ideas from our simulations to the conservation of wild birds.
2.  Our spatial model incorporates empirically derived variation in breeding output between habitats, density dependence and dispersal. The outputs indicate that dispersal can have considerable consequences for population abundance and distribution. The abundance of a species within a patch can be markedly affected by the surrounding habitat matrix.
3.  Dispersal between habitats may result in lower population densities at the edge of good quality habitat blocks and could partially explain why some species are restricted to large habitat fragments.
4.  Habitat deterioration may not only lead to population declines within that habitat but also in adjacent habitats of good quality. This may confound studies attempting to diagnose population declines.
5.  Although mobile species have the advantages of colonizing sites within metapopulations, dispersal into poorer quality territories may markedly reduce total populations.
6.  There are two main approaches to conservation: one is to concentrate on establishing and maintaining protected areas, while the other involves conservation of the wider countryside. If dispersal is an important process then protecting only isolated areas may be insufficient to maintain the populations within them.     

Hyper-oceanic liverwort species of conservation concern: evidence for dispersal limitation and identification of suitable uncolonised regions

In order to successfully manage and conserve species and plant communities, it is important to have a good understanding of their ecology and distributions. The three liverwort species Anastrophyllum donnianum, Scapania ornithopodioides and Scapania nimbosa, are restricted to the mixed northern hepatic mat community found in the most oceanic parts of north-western Europe. These species are of conservation concern because they are globally rare with strict environmental requirements and a limited dispersal potential, which makes them vulnerable to disturbance and climate change. In this study we used species distribution modelling to (1) predict their potential distribution in Norway (2) to assess whether they are limited by dispersal or suitable climate, (3) identify which climatic factors are most important in determining their distribution and (4) suggest regions for further field based surveys. Maximum entropy (MaxEnt) models were developed for each species using target-group background data, and five environmental coverage layers. Our results indicate that all three species are limited by dispersal rather than the availability of suitable areas in Norway. In particular, A. donnianum seems to be limited from reaching uncolonised highly suitable areas in northern Norway due to a barrier unsuitable region with insufficient summer rain. S. ornithopodioides is absent from northern Norway despite the presence of highly suitable regions scattered along the coast. The models locate highly suitable areas where conservation measures should be focused when they overlap with known populations. Areas of interest for targeting searches for potentially undiscovered populations are indicated.     

Landscape scale conservation: resources, behaviour, the matrix and opportunities

Landscape scale conservation efforts are becoming more commonplace in conservation, with a move from single species to multi-species initiatives. These initiatives are reliant on modelling processes, largely underpinned by metapopulation models. We argue that generic models developed for individual species in particular landscapes over selected time periods may only be applicable to alternative landscapes and time periods in restricted circumstances. Variability in species responses to landscapes and environmental conditions is dependent on a range of species-specific intrinsic characteristics, dependent on their responses to resources, (including weather) and also individual states. We propose that the behavioural component of how species respond to resources needs to be taken into account in modelling species responses to landscape, and therefore how limited resources for conservation are deployed. Species behaviours are inherently complex. We argue that because of this complexity the conservation of the majority of species, especially of the least rare, may be best served if conservation effort is additionally focused on increasing landscape heterogeneity and disturbance. This may also facilitate persistence in the face of climate change. We suggest that heterogeneity should be promoted through agri-environment schemes.