Guidelines for the ex situ conservation of target plants based on links of their collection data with geodatabases (from Krigas et al., 2010, with modifications).
In the frame of the global efforts to halt the biodiversity loss by 2010 and with the aim to develop effective conservation strategies extending beyond 2010, stakeholders have recognized as a priority the in situ conservation (on site conservation) of target plant species.
Still, the rapid environmental changes including climate change, habitat loss and alteration, could pose some limitations on our ability to conserve target species effectively in situ (Sharrock & Jones, 2009). As a result, conservation biologists, policy makers and managers acknowledge the importance of ex situ conservation of target plants in botanic gardens and seed banks as an essential back-up solution (Convention on Biological Diversity [CBD], 1992; Glawka et al 1994; Global Strategy for Plant Conservation [GSPC], 2002; European Strategy for Plant Conservation [ESPC], 2009; Sharrock & Jones, 2009).
For the ex situ plant conservation, target species mainly refer to plant taxa (species and subspecies) presenting a narrow distribution in the wild (see Krigas & Maloupa, 2008). This category of plants usually includes:
Local endemics (endemics of a single mountaintop e.g. Viola cephalonica (Katsouni et al., 2009), or endemics of a single island e.g. Allium samothracicum (Krigas, 2009), or endemics of a group of nearby areas or islands e.g. Thymus holosericeus (Krigas et al. 2010),
Regional endemics (endemics to small parts of a single country, e.g. endemics of southern Spain, endemics of Peloponnese, southern Greece),
National endemics or single-country endemics (e.g. Greek endemics, Italian endemics, Spanish endemics),
Endemics to specified small geographical areas e.g. local Balkan endemics transcending the borders of neighbouring Balkan countries such as Ranunculus cacuminis (Krigas & Karamplianis, 2009).
Other target species significant for the ex situ plant conservation may include plants which are rare in a certain area (e.g. Europe, Sharrock & Jones, 2009) or plants that are currently threatened with extinction at local, regional or global level i.e. taxa characterized as “Near Threatened”, “Vulnerable”, “Endangered” or “Critically Endangered” according to the IUCN (2001) criteria. However, given that almost 90% of the Europe’s threatened plants are single-country endemics, it should be noted that most of the endemic plants are also threatened with extinction (Sharrock & Jones, 2009). Last but not least, other groups of socioeconomically valuable plants (e.g. saffron) and their progenitors (e.g. plants in the genus Crocus) may also be considered as target plants for the ex situ conservation (Fernández et al., 2011).
GIS has be given a role in analyzing potential and current spatial distribution of target species, locating and assessing the populations of target plant species and assemblages, measuring biodiversity, monitoring biodiversity patterns and identifying priorities for conservation and management (Iverson & Prasad, 1998; Salem, 2003; Powel et al., 2005; Pedersen et al., 2004).
Habitat evaluation or habitat modeling with the use of GIS has the potential to make a substantial contribution to conservation management of target species within an integrated approach and is suitable for setting conservation priorities at multiple spatial scales (Store & Jokimäki, 2003; Powel et al., 2005). GIS have also been used as a tool for specific conservation programmes including comparisons of ecological patterns between local and regional scales, selection of protected areas according to habitat suitability, analysis of the impact of alien species on endemic plants and selection of sites for representative seed collections of target species (Draper et al., 2003). Flexible GIS-based tools have also been developed to exploit static information of botanical collections in an attempt to evaluate species distributional ranges (Schulman et al., 2007; Loiselle et al., 2008), accounting for potential effect of climate change to predicted models (Loiselle et al., 2008). Other GIS-tools and distribution modeling methods have been applied to examine the hypothesis that wild and cultivated plants of certain species may occur in the same types of habitats (Allison et al., 2006).
Currently, the GIS technology has increasingly been used for predictive purposes in species re-introductions. Combining historical information from specimen labels with up-to-date environmental data, GIS can be used to identify the range of environmental conditions in which plants grow, offering an understanding of the ecological requirements of different species. The relevant environmental conditions can then be used to delimit areas of high, moderate or low survival probability (Sawkins, 1999 as cited in Moat & Smith, 2003; Powel et al., 2005). Recent GIS applications further include studies on the assessment of the importance of landscape connectivity, structure and configuration for native and non-native plant communities, dispersal and invasiveness abilities (Minor et al., 2009). Nevertheless, the most frequently encountered obstacle to the use of GIS technology in conservation planning is lack of data, especially distribution data of target species and digital vegetation maps of areas with conservation interest (Sawkins, 1999 as cited in Moat & Smith, 2003).
The GIS technology has also an enormous potential in seed conservation, particularly in targeting collecting needs for botanic gardens and conservation institutes and in identifying what, where and when to collect (Moat & Smith, 2003). Although concerns are raised regarding limitations and biases (Store & Kangas, 2001), some of the GIS applications have been used for their power to pinpoint by spatial niche modeling, new probable locations where rare endemic species may be found in the wild, thus permitting the search for new populations (Jarvis et al., 2005). The GIS could also be used for assessing the sensitivity of target species to climate change identifying potential distributions as well as vulnerable habitats and species (Vanderpoorten et al., 2006). In this way GIS may deliver important information that can drive seed banking priorities and design (Godefroid & Vanderborght, 2010).
Lately, a new application of GIS has been launched for the ex situ plant conservation; GIS was used to describe quantitatively and qualitatively the natural habitats of target plants in order to facilitate their propagation and transfer from the wild habitats to man-made habitats like botanic gardens (Krigas et al., 2010).
2. GIS used for the description of the natural habitats of target species
The geographical data associated with plant collections may be considered as a set of facts about the places in which the plants thrive. In the wild, target plants for ex situ conservation could thrive literally anywhere. Given the spatial and temporal heterogeneity of the environmental factors and the dissected topography of the landscape, the target plants may well originate in a variety of quite different habitats in which they are adapted to grow naturally. Hence, it seems quite difficult to be able to emulate their preferable conditions when trying to cultivate them in restricted man-made habitats such as botanic gardens (Krigas et al., 2010). A deeper understanding of the ecology and life cycle of such target species has been considered as a key issue towards a species-specific successful propagation and cultivation method (Baskin & Baskin, 1988).
In this framework, the GIS can be used to offer a reliable, quantitative and qualitative description of the in situ habitat conditions preferred and/or tolerated by different target plant species in the wild. This novel GIS application is both ecologically meaningful and useful in horticulture and ex situ plant conservation (Schulman & Lehvävirta, 2010).
To demonstrate this application a dataset was chosen including target plants originating from sites of varied landscapes that are also subjected to different climatic conditions (Fig. 1): the Aegean Archipelago, Crete, Ionian Islands, and Peloponnese (Greece, Southern Europe). The target plants included in this dataset fall into the conservation priorities of the Balkan Botanic Garden of Kroussia (BBGK, Krigas & Maloupa, 2008, Krigas et al., 2010). To date, the BBGK has organized several botanic expeditions all over Greece in order to collect appropriate plant material for propagation and ex situ conservation. All this plant material is currently maintained under ex situ conservation (ca. 25% of the known Greek flora which includes at least 6.300 species and subspecies, Krigas et al., 2010).
The positions of the collection sites of target plant species were captured in the wild using handheld GPS trackers. The obtained geographic coordinates were consequently imported as point layer into a Geographical Information System (GIS) and point sampling was performed for each one on multiple raster and polygon layers. In order to probe values for topography, terrain, soil, climatic, land cover and habitat attributes at the captured sites, the following datasets were selected (Fig. 2):
Raster elevation data from SRTM (USGS 2004), with resolution of 1 km2 (30 arc second) which were used for terrain and topography attributes.
Soil data from the European Soil Database (ESDB) v2.0 (EC, 2004), which is composed of the Soil Geographical Database of Eurasia at a scale of 1: 1,000,000 (version 4 beta) and the Pedotransfer Rules Database (v2.0), with a raster resolution of 1 km2, presenting 72 soil parameters.
Temperature and precipitation data from the WorldClim database (Guarino et al., 2002; Hijmans et al., 2005), with a raster resolution of 1km2, which has been used for the description of climatic conditions (average values of 50 years).
Land cover data from CORINE (Coordination of Information on the Environment) comprehensive hierarchical vector geodatabase at a scale of 1: 100,000 (with a minimum mapping unit of 25ha) which present the spatial distribution of different landcover/land-use types (CORINE land cover classification, EC & ETC/LC, 1999) and soil types (CORINE soil classification EC, 1985).
Additionally, part of the initial data was processed to produce more specific attributes for the collection sites of the target plants, as follows:
The elevation data (DEM) was used for raster based terrain analysis, which resulted in slope and aspect maps of the Greek territory.
The DEM was further used as the base layer for the digitization of the vegetation zones of Greece according to Mavromatis (1980).
The rasters describing the spatial variations of precipitation, maximum and minimum temperatures from the WorldClim geodatabase (Guarino et al., 2002), were used in map algebra calculations for the production of a raster map which displays the spatial variation of the Emberger Pluviothermic (Ombrothermic) Quotient as: 2000*P/(Tmax+Tmin)*(Tmax-Tmin), where P: the layer of annual precipitation (mm), T: the layers of mean maximum (Tmax) and minimum (Tmin) monthly temperature of the warmest and coldest month in Kelvin degrees. Precipitation (P) Seasonality was calculated also, using the following map algebra expression: 100* (Pw -Pd ) / Py, where Pw and Pd are the raster layers for the spatial variations of precipitation for the wettest and driest quarter of the year respectively, and Py the total annual precipitation (Fig. 1).
Based on this GIS application, simple or advanced ecological fact sheets may be constructed for different target species which actually reveal their preferences in the wild (Fig. 2, 3, 4). An ecological fact sheet illustrates the ecological profile of a wild growing target plant and can be designed in a way to include different kind of information such as: Vegetation zone (different types), Climatic data which is a combination of Precipitation and Temperatures (for the different sites: total annual and annual range of precipitation, driest and wettest month, minimum, mean and maximum temperatures, annual and diurnal temperature range, isothermality and seasonality, Emberger pluviothermic quotient), Topographic (for the different sites: elevation, aspect, slope), Habitat (bibliographic, field notes), Land Cover Types (for the different sites: CORINE classification in three levels) and Geological-Pedological data (for the different sites: Food and Agriculture Organization’s [FAO] soil classification, World Reference Base Soil classification, dominant parent material in three levels, depth to rock, textural class, topsoil base saturation, subsoil water capacity) (see Fig. 2, 3, 4).
Additionally, other information may also be associated with the ecological description of the wild habitat of target species such as Taxonomic data i.e. taxon’s name, family, accession number (ASN) given, Collection data (e.g. geographical coordinates, description of state, province, exact locality etc), Conservation assessment (e.g. ranking according to priorities assigned), and Mother Plantations (number of total plant accessions or number of records). It should be mentioned that when the number of records introduced in GIS for a specific information field are >1, then any quantitative information may be described by the mean value and its standard deviation (± SD) (see Fig. 2 and 3).
3. GIS-facilitated development of protocols for ex situ conservation of target species
Considering the recent challenges in regional conservation planning, it becomes apparent that there is an urgent need for increased applied research in order to develop propagation and cultivation protocols for target plants threatened with extinction, towards species recovery and populations’ reinforcements (Bunn et al. 2011, Maunder et al. 2001 Sarasan et al. 2006). Moreover, the GSPC (2002) and the ESPC (2009) have included this urgent need under their conservation targets at European and global level (Target 8). The GIS may serve such a need and may help at the development of species-specific propagation protocols and ex situ cultivation guidelines regarding target species. Such methodologies could also provide basic information and criteria for prioritizing collections of threaten or rare species based on their distributional patterns, population status and the genetic and/or geographic representation of current seed bank collections (Draper et al., 2003; Farnsworth et al., 2006) or even prioritizing sites for seed collections (Jarvis et al., 2005; Ramírez-Villegas et al., 2010).
3.1. GIS and seed germination
The GIS may be used to facilitate the germination of seeds collected from the wild in plant propagation studies as shown by Krigas et al. (2010). This study included plants originating at the Ionian Islands, south-western Greece and provided some example-cases.
Generally, the appropriate season for germination trials inside the greenhouse was selected by comparing the seasonal temperatures profiles of the local greenhouse used with those of the wild habitat of the target species (Ionian Islands). The season deemed as more appropriate was characterized by temperature ranges that could easily mimic those prevailing in the natural environment of the target species.
To illustrate an example, the GIS-derived temperature profiles for the wild habitat of Silene cephallenia subsp. cephallenia (Figs. 3, 5) have dictated the selection of temperatures to test for seed germination, leading to a germination success of 64% (Krigas et al., 2010). Additionally, its ecological profile has explain the fact that seed germination was inhibited at 10oC, whereas seed germination was considerably increased in only 7 days when higher temperature (21oC±1) was applied, in an attempt to emulate natural conditions.
3.2. GIS and asexual plant propagation by cuttings
Basically, the asexual propagation and the rooting trials of softwood cuttings from plants are performed in greenhouse conditions using a few individuals to produce large amounts of genetically identical plants. Lately, it has been shown that the GIS may also be used to facilitate the asexual plant propagation by cuttings (Krigas et al., 2010). For example, the GIS-derived data for the wild habitat of Thymus holosericeus demonstrated that early spring was the most appropriate season for the rooting trials of this target species (Krigas et al., 2010). During early spring, the temperatures of the selected greenhouse in their case have emulated in the best way the temperatures prevailing in the natural habitat of the target plant. In this study, during propagation the rooting substrate’s temperature was kept at 18-21°C in order to accelerate rooting as indicated from previous experience (Maloupa et al., 2008). Nevertheless, the air temperature was kept between 18-25°C, in an attempt to emulate as best as possible the original conditions of the natural habitat which were indicated by the GIS. Furthermore, the relative humidity was kept at 80% for the first 7 days and was reduced gradually to 50% during the second week of rooting. This was followed due to the fact that Th. holosericeus is a xerophytic species that grows in areas of very low subsoil water capacity, especially during dry months (Fig. 2). In the case of Th. holosericeus, the combination of GIS data with previous experience on rooting of other species of the same genus raised propagation success nearly by 90% (from 45% to 80% rooting).
3.3. GIS and in vitro plant propagation
The attempts of in vitro propagation of rare and threatened plant species are often associated with two inherent problems which may hold back conservation efforts. First of all, there is frequently a lack of published methods regarding the propagation of a certain plant species and secondly, there is often a limited amount of experimental plant material which can be initially available due to scarce populations of limited size found in the wild (Bunn et al., 2011; Krogstrup et al., 2005). Taken these limitations into account, almost every attempt to propagate rare and threatened plants is of great importance but seems difficult to achieve.
Although sophisticated technologies and modern methods have been used to date for the in vitro plant propagation (Benson, 1999), the GIS has not been exploited as a tool. Lately, Grigoriadou et al. (2011) have shown how the GIS may also be used to serve the needs and procedures of in vitro plant propagation. Using a case-study plant i.e. Achillea occulta which is a local endemic of southern Peloponnese (Southern Greece) recently characterized as “Vulnerable” (Constantinidis & Kalpoutzakis 2009), the authors have used GIS in this study for the:
Selection of temperatures for both greenhouse cultivation and in vitro cultures; the GIS-derived ecological profile for A. occulta dictated the selection of 22±2 oC day temperature and 15±2 oC night temperature at 16-h photoperiod to be used as most suitable for the development of the in vitro cultures.
Selection of appropriate period for acclimatization and transplanting of plantlets produced in vitro; after balancing out the temperature profiles of the wild habitat with those prevailing in the man-made site of the botanic garden (BBGK), the GIS revealed that spring temperatures were more suitable for the active growth and acclimatization of plantlets.
Selection of growing media and substrates for plantlets produced in vitro; the type of commercial peat used with the addition of vermiculite provided a very good imitation of the natural soil conditions as indicated by the GIS-derived ecological profile.
Selection of appropriate ex situ conservation sites for plants raised in vitro; after balancing out the temperature profiles of the wild habitat with those prevailing in the available man-made ex situ conservation sites of BBGK, the GIS revealed that specific sites seemed more favorable than others for the accommodation of A. occulta plants (a site with temperature range as close as possible to the natural temperature range of the wild habitat was chosen).
4. GIS-derived ecological profiles and guidelines for the ex situ cultivation of target plants
From the above mentioned and when taking into account the associated technical information (see Krigas et al., 2010, Grigoriadou et al., 2011) it becomes apparent that GIS may be used for the development of effective protocols concerning the propagation and initial cultivation of plant material derived from target species.
Regardless the method used for plant propagation (cuttings, seeds or in vitro techniques), the young individuals produced (plantlets or seedlings) require hardening and acclimatization before their ex situ conservation. In this sense, the GIS-derived ecological profiles of the target plants could be used to provide specific guidelines for their effective ex situ cultivation (Table 1).
4.1. Cultivation guidelines regarding soil media, potting volume, texture, pH and drainage
In general, it is known that for the successful ex situ cultivation of target plants, the plant medium to be used must be similar to that of the substrate in the plant’s natural habitat, providing similar root aeration and drainage conditions. This is quite important since improved drainage conditions during cultivation can actually inhibit fungal disease risks, induce greater rooting depth and enhance general plant health and vigor (Brady & Weil, 2002).
The GIS-derived ecological profile for the wild habitat of Silene cephallenia subsp. cephallenia (Fig. 3) showed that the plants originally grow on “Calcaric Lithosol” according to the FAO (1985) classification or according to the European Soil Database, on “Calcaric Leptosol (mountainous), shallow (<25 cm) or extremely gravelly soils directly over continuous rock or soils having <20% (by volume) fine earth material” (Krigas et al., 2010). In an attempt to emulate the natural habitat during hardening and acclimatization of plantlets raised from seeds (seedlings), the type of commercial peat used in BBGK for transplantation contained lime and by adding vermiculite, a good approximation of its originally drained soil type was achieved. This fact has actually allowed the plantlets of S. cephallenia subsp. cephallenia to continue growing without problems observed.
For the further ex situ cultivation of Silene cephallenia subsp. cephallenia and Thymus holosericeous, the GIS-derived ecological profiles (Fig. 2, 3) indicated that the basic soil group in which their wild habitats originate from is classified as ‘‘Calcaric Lithosol’’ (stony calcareous with a high concentration of MgCO3 and >15% free CaCO3, developed on dolomitic limestone). Such a substratum is characterized by a good drainage capacity, neutral to alkaline soil pH, low depth and a high ratio of stones to fine earth. The above indicated that for the ex situ cultivation of these target plants, a potting medium of relative high pH would be required and a fair degree of drainage was deemed essential. To accomplish this, supplementary perlite, sand and/or fragmented stone were added in their growing media. For these plants, medium sized pots (4.5 l) were suggested as suitable and additional Mg dressing was added in order to match the original chemical composition of their natural habitats.
By adopting these guidelines (Table 1), the natural habitat of the target plants was technically emulated with common commercial materials and the plants have adapted well and continued to grow without apparent problems (Krigas et al., 2010).
4.2. Cultivation guidelines regarding temperature range
When cultivating plants from the wild to man-made habitats, the temperature conditions at the plant’s growing site (nursery or outdoors) may often be quite different from those prevailing in the plant’s original wild habitat. Although it is known that plants usually have a degree of tolerance for a wide range of temperatures, it is important to know the temperature range that a plant species may tolerate, in order to facilitate its growth by maintaining temperatures within these limits during cultivation.
The GIS-derived ecological profile indicated that Silene cephallenia subsp. cephallenia (Fig. 3, 5) may experience and/or tolerate in its wild habitat mean temperatures ranging from 6.7 oC to 32.2 oC throughout the year, while for Thymus holosericeus the mean yearly temperatures may range from 3.9 oC to 29.5 oC (Krigas et al., 2010 and Fig. 2).
For the acclimatization procedure of the seedlings of S. cephallenia subsp. cephallenia and of the plantlets of Th. holosericeous produced in BBGK, the selection of appropriate sites was achieved after balancing out the temperature profiles of the available areas for ex situ conservation in northern Greece with the natural range of temperatures of their wild habitats, as revealed with the use of GIS (Table 1). It was suggested that Th. holosericeus may be marginally stressed during hot summer days and short term measures could possibly be taken to avoid heat shock (e.g. periodical shading or translocation of mother plants to cooler conditions). However, high summer temperatures did not seem to be a constraint for S. cephallenia subsp. cephallenia. Moreover, it was suggested that accommodation in a protected greenhouse would be crucial for the winter survival of both plants in northern Greece (Krigas et al., 2010). Indeed, the propagated plants that were transferred indoors (greenhouse at sea level, with controlled winter indoor temperatures ranging from 5 to 25 oC), have actually shown increased height, leaf area and number of flowers during cultivation in comparison to those transplanted outdoors (Krigas et al., 2010).
4.3. Cultivation guidelines regarding watering regimes
When transferring wild plants to man-made sites for their ex situ cultivation, the amount of water to be offered to them remains largely unknown. The watering regime followed is based merely on observations regarding the natural habitat of the species in question or exploits previous general horticultural experience associated with the cultivation of other species with presumably similar needs. However, it is generally accepted that the design of an irrigation system for the ex situ cultivation of target plants should take into account the natural preferences of the species, the medium type and the irrigation frequency requirements. The latter not only depends on the specific plants in question, but it is also influenced by the growing season and the indoor or outdoor temperatures prevailing in the cultivation sites.
The precipitation profiles derived from GIS for the target plants may indicate differences regarding the water requirements preferred and/or tolerated by each one of them in the wild. For example, the GIS-derived ecological profile of A. occulta published by Grigoriadou et al. (2011) for its ex situ conservation, indicated a watering regime equal to a mean total annual precipitation of 744 mm (7–136 mm per month) which was followed for the proper cultivation of the in vitro propagated plants.
Seasonal variation of the watering regime is equally important as the total amount of water offered to plants. To illustrate an example, the GIS-derived ecological profiles of Thymus holosericeous and Silene cephallenia subsp. cephallenia may be taken into account (Fig. 2, 3, 5, 6). It becomes evident that during the wettest and driest quarters of the year, Thymus holosericeus’s habitat receives from 40 to 504 mm, while that of Silene cephallenia subsp. cephallenia from 26 to 476 mm. During autumn, no noticeable differences exist regarding mean monthly precipitation in the natural habitats of these plants. However, from January to August mean monthly precipitation is consistently higher in the intermediate altitude habitats of Th. holosericeus, while until autumn S. cephallenia subsp. cephallenia (which is naturally found close to sea level) receive comparatively lower precipitation (Fig. 5, 6).
Hence, the GIS-derived precipitation profiles suggest that the watering need (both in terms of water amount received and frequency of watering) is not the same for these plants (Table 1), although both should be under a rather low water regime (regardless of whether it is winter or summer). S. cephallenia subsp. cephallenia has comparatively lower water demands both annually and seasonally which should result in a more restricted watering schedule, while Th. holosericeus has somewhat intermediate watering needs, although a relatively low water regime seems to be equally suitable since it is considered as a xerophytic species (Krigas et al., 2010).
4.4. Guidelines regarding positioning of target plants in displays
The qualitative and quantitative description of the natural habitat of a target species may offer information for appropriate spatial and temporal positioning in plant displays of botanic gardens. Different vegetation types where a target plant is naturally found (deciduous or evergreen i.e. depending on the canopy cover of the vegetation) or land cover types (e.g. rock formations, woodland, pastures etc) from which the target species originate from, are attributes that can be exploited as important ecological information. Such attributes (a) may indicate appropriate or unsuitable sites for the ex situ cultivation of target plants, (b) could be useful for the selection of the amount of light or shading needed for the plants or to be avoided by them, and (c) could define the species assemblages with common requirements for specific indoors or outdoors plant displays (Table 1).
To illustrate an example, the GIS-derived ecological profile of Achillea occulta published by Grigoriadou et al. (2011) for its ex situ conservation indicated that (semi-) shady limestone cracks and rock bases with calcaric lithosols should be used as habitats in order to host the propagated plants and a natural positioning at south, south-eastern and south-western exposures of rock formations was chosen as more favorable for plant growth.
5. Potential and implications for the management of living plant collections
The novel GIS-facilitated application presented here is a powerful tool able to extract ecologically meaningful environmental information from geodatabases regarding the collection sites of different target plants which are useful in applied research and horticulture. This application is able to identify important ecological differences that can contribute to the development of species-specific baseline plant propagation and cultivation protocols. Given the impracticality and lack of on-the-spot field temperature and precipitation measurements and proper soil sampling followed by laboratory analysis, the nothing (just delete the words) geodatabases with the use of GIS can be used to extract at a fraction of time, information crucial for the success of ex situ conservation of target species. This application can be used to (Table 1):
|Variable / Source used||Selected attributes used||Conservation guidelines produced||Potential to rank or filter plants in terms of different quantitative or qualitative variables or to group target plants sharing common requirements|
|Soil moisture / ESDB v.2 (EC, 2004)||Available topsoil and subsoil water capacity||Calculation of different watering regimes for different groups or target species|
|Soil classes and types / ESDB v.2 (EC, 2004), CORINE Soil Classification (EC, 1985)||Textural class|
Different soil classes
Dominant parent material
|Selection of different growing media (regarding texture, pH, drainage) for different groups or target species|
|Soil nutrient / ESDB v.2 (EC, 2004)||Topsoil and subsoil base saturation|
Cation exchange capacity
|Selection of different growing media and development of fertilization regimes for different groups|
|Soil limitations / ESDB v.2 (EC, 2004)||Depth to a gleyed horizon|
Depth to rock
Depth of an obstacle to roots
Volume of stones
|Selection of different growing media (regarding texture, drainage) and potting volume for different groups or target species|
|Climate / WorldClim|
Database (Guarino et al., 2002, Hijmans et al., 2005)
Mean minimum or maximum temperatures of the coldest or the warmest month
Annual mean temperature range
Mean diurnal temperature range
Precipitation of the driest month or the wettest month
Mean monthly precipitation
Mean precipitation of driest, wettest, coldest or warmest quarter
|Selection of appropriate sites and conditions both in greenhouse and in ex situ cultivation sites for different groups or target species|
Selection of temperatures for seed germination and asexual propagation for different groups or target species
Shading and ventilation for temperature regulation
Calculation or watering regimes, calibration of different watering regimes in different seasons and/or in different months for different groups or target species
|Topography / Digital Terrain Model created||Aspect, Slope,|
Altitude (elevation from sea level)
|Customization of microclimate in ex situ cultivation sites and appropriate positioning in plant displays|
|Vegetation zones / Mavromatis (1980)||11 different vegetation types identified for the Greek territory||Selection of the ex situ conservation sites for different groups or target species|
Selection of shading regime for different groups (seasonal, if originating from deciduous vegetation or all year round, if originating from evergreen vegetation)
or for target species
Creation of species assemblages
Selection of sites for specific plant assemblages and displays
|Land cover classes and types/ CORINE Land cover (EC & ETC/LC, 1999)||45 different land-use classes and types|
Indicate the preferable ex situ growing conditions for each target plant (linking the in situ natural conditions with the ex situ cultivation regimes) and provide guidelines regarding species-specific treatments (Fig. 2, 3, 5, 6),
Organize groupings of target plants based on ecological criteria (groups of plants with similar preferences or requirements), thus possibly improving their growing conditions as well as saving human-hours and space in ex situ conservation areas (Fig. 7, 8),
Pinpoint target plants that may or cannot be accommodated in specific areas,
Reduce trial-and-error losses during the ex situ cultivation of target species which seems to be common in the community of botanic gardens, often due to absence of previous experience (Krigas et al. 2010),
Formulate and establish species-specific guidelines for the ex situ cultivation of target plants in botanic gardens,
Facilitate the gap analysis of the botanic expeditions organized for the collection of plant material (which may also permit better planning of future ones),
Reveal gaps in the representation of target plants from different altitudes, vegetation zones, habitat types, phytogeographic and climatic regions of specified geographical areas,
Pinpoint by spatial niche modelling new probable locations where target species may be encountered, permitting the search for new populations in the wild (Jarvis et al., 2005),
Assess conservation strategies and actions of institutions related to plant conservation.
By exploiting the GIS-derived ecological information for target plant species, the Balkan Botanic Garden of Kroussia (Greece) was the first to initiate this pilot GIS application dedicated to the ex situ plant conservation (Krigas et al., 2010). To date the majority of the target plants collected from the wild and propagated at the grounds of the BBGK are able to grow and flower regularly and produce fruits with no problems reported so far (BBGK, pers. comm.). Additionally, their seeds are regularly collected and deposited in a seed bank for future studies. This valuable material of conservation important target plants -in case of catastrophic events and if deemed necessary- could serve as a means to enrich the wild plant populations with individuals raised ex situ, actually reducing the risk of their extinction (Bowes, 1999; Bunn et al., 2011).
This novel GIS application described here presents an invaluable (time and money saving) tool with a broad-scale potential in enhancing the prospects of the ex situ plant conservation of target species collected from diverse environmental conditions and transferred to man-made sites such as botanic gardens, nurseries and private gardens.
The authors would like to thank Dr E. Maloupa and the Balkan Botanic Garden of Kroussia (Greece) for funding earlier stages in this research and appreciate access to the plant material conserved ex situ in its grounds. The field work of N. Krigas in the Ionian Islands, SW Greece was partially supported by the Stanley Smith Horticultural Trust (UK) in the frame of the Ionian Island Project (Collections of rare, threatened and endemic plants of the Ionian Islands for their ex situ conservation in Greek and British botanic gardens). The work of A. D. Mazaris was partially supported by the EU FP7 SCALES project (‘Securing the conservation of biodiversity across administrative levels and spatial, temporal and ecological Scales’; project #226852).