Relationship between population size and genetic diversity in endangered populations of the European bullhead (Cottus gobio): implications for conservation

This study investigated the relationship between the current size of endangered bullhead (Cottus gobio) populations and microsatellite genetic variability. Additionally, the microsatellite data were used to evaluate whether a genetic test for population bottlenecks was able to provide evidence of recent severe population declines. Finally, our results were used to develop conservation priorities and measures. Population size appears to be a crucial parameter in determining the amount of genetic diversity that can be preserved in bullheads, since a significant positive correlation was observed between both variables. Furthermore, in some populations we were able to detect genetic signatures of the documented decline in population size. We suggest that the most immediate goal for bullhead conservation should be to increase the size and the range of the populations, and in doing so minimise or even reverse further genetic erosion. Potential management actions like habitat quality improvement, reduction of river fragmentation and supplementation programmes (translocation, supportive breeding) are discussed.     

The paradox of keystone species persecuted as pests: A call for the conservation of abundant small mammals in their native range

Small mammals, such as European rabbits (Oryctolagus cuniculus), plateau pikas (Ochotona curzoniae) and prairie dogs (Cynomys spp.), traditionally have been perceived as pests and targeted for control within their native ranges, where they perform essential ecosystem roles and are considered keystone species. These species can reach high densities, and have been subjected to eradication campaigns because of their putative negative impact on natural habitats and agriculture and their competition with livestock for forage. Eradication programmes have been a main factor causing sharp declines of these species in their natural ranges. Paradoxically, they are keystone species where they are abundant enough to be perceived as pests. The term “pest” is usually a social perception that is rarely supported by scientific data, whereas there is considerable scientific evidence of the key ecological roles played by these species. We call for the conservation of these species and present a conceptual model regarding the management of their populations. Where they occur at high numbers, and hence their effects on biodiversity are still of crucial importance, the persecution of these species should be avoided and their natural habitats preserved. In areas with high conservation value, but where these species occur at low densities, management efforts should aim to increase their density. In areas of high commercial value, managers ideally should consider changing prioritization of the area to high conservation value by purchasing the land or obtaining conservation easements. In situations with high commercial value and demonstrable low conservation concern, small mammals could be reduced humanely.     

The giant squid Architeuthis: An emblematic invertebrate that can represent concern for the conservation of marine biodiversity

The current public perception is that there is little reason for concern for the conservation of marine invertebrates, in part due to the scarcity of emblematic species to represent that diverse group. This paper shows that giant squid can be considered an emblematic species to represent concern for the conservation of marine invertebrate biodiversity because it satisfies all the requirements of an emblematic species. It shows that Architeuthis attracts public interest and attention and can serve as an indicator of oceanographic conditions and ocean climate change. It asserts that Architeuthis can represent concerns for vulnerable marine ecosystems associated with submarine canyons and that it belongs to a broad diverse phylogenetic group of organisms associated with these canyons, sharing common concerns with that group with respect to vulnerability and conservation. This study also advocates that the giant squid can serve as an indicator of effects of ecosystem stress resulting from anthropogenic effects including ocean acidification and warming. It is also shown to be vulnerable to such anthropogenic effects as fishing, acoustic seismic exploration and, possibly, pollutants.     

Microsatellite analysis of genetic population structure of the endangered cyprinid Anaecypris hispanica in Portugal: implications for conservation

The endangered fish species Anaecypris hispanica is restricted to eight disjunct populations in the Portuguese Guadiana drainage. The genetic structure of these populations was studied in order to determine levels of genetic variation within and among populations and suggest implications for conservation of the species. Based on five microsatellite loci, the null hypothesis of population homogeneity was tested. Tests for genetic differentiation revealed highly significant differences for pairwise comparisons between all populations, and substantial overall population subdivision (F_ST=0.112). All sampled populations contained unique alleles. Our findings indicate marked genetic structuring and emphasise limited dispersal ability. The high levels of genetic diversity detected within and among A. hispanica populations suggest, however, that the observed fragmentation and reduction in population size of some populations during the last two decades, has impacted little on levels of genetic variability. Data imply that most A. hispanica populations should be managed as distinct units and that each has a high conservation value containing unique genetic variation. It is argued that geographic patterns of genetic structuring indicate the existence of eight management units.     

Triage for conserving populations of threatened species: The case of woodland caribou in Alberta

Prioritization of conservation efforts for threatened and endangered species has tended to focus on factors measuring the risk of extirpation rather than the probability of success and cost. Approaches such as triage are advisable when three main conditions are present: insufficient capacity exists to adequately treat all patients, patients are in a critical state and cannot wait until additional capacity becomes available, and patients differ in their likely outcome and/or the amount of treatment they require. The objective of our study was to document the status of woodland caribou (Rangifer tarandus) herds in Alberta, Canada, with respect to these three conditions and to determine whether a triage approach might be warranted. To do this we modeled three types of recovery effort - protection, habitat restoration, and wolf control - and estimated the opportunity cost of recovery for each herd. We also assessed herds with respect to a suite of factors linked to long-term viability. We found that all but three herds will decline to critical levels (<10 animals) within approximately 30 years if current population trends continue. The opportunity cost of protecting all ranges by excluding new development, in terms of the net present value of petroleum and forestry resources, was estimated to be in excess of 100 billion dollars (assuming no substitution of activity outside of the ranges). A habitat restoration program applied to all ranges would cost several hundred million dollars, and a provincial-scale wolf control program would cost tens of millions of dollars. Recovery costs among herds varied by an order of magnitude. Herds also varied substantially in terms of their potential viability. These findings suggest that woodland caribou in Alberta meet the conditions whereby triage should be considered as an appropriate conservation strategy.     

The role of demographic compensation theory in incidental take assessments for endangered species

Many endangered species laws provide exceptions to legislated prohibitions through incidental take provisions as long as take is the result of unintended consequences of an otherwise legal activity. These allowances presumably invoke the theory of demographic compensation, commonly applied to harvested species, by allowing limited harm as long as the probability of the species’ survival or recovery is not reduced appreciably. Demographic compensation requires some density-dependent limits on survival or reproduction in a species’ annual cycle that can be alleviated through incidental take. Using a population model for piping plovers in the Great Plains, we found that when the population is in rapid decline or when there is no density dependence, the probability of quasi-extinction increased linearly with increasing take. However, when the population is near stability and subject to density-dependent survival, there was no relationship between quasi-extinction probability and take rates. We note however, that a brief examination of piping plover demography and annual cycles suggests little room for compensatory capacity. We argue that a population’s capacity for demographic compensation of incidental take should be evaluated when considering incidental allowances because compensation is the only mechanism whereby a population can absorb the negative effects of take without incurring a reduction in the probability of survival in the wild. With many endangered species there is probably little known about density dependence and compensatory capacity. Under these circumstances, using multiple system models (with and without compensation) to predict the population’s response to incidental take and implementing follow-up monitoring to assess species response may be valuable in increasing knowledge and improving future decision making.     

Managing successional species: Modelling the dependence of heath fritillary populations on the spatial distribution of woodland management

Species that persist on a shifting mosaic of successional habitat offer particular challenges to conservation, to monitoring methods, and to population dynamic modelling. The conservation of the heath fritillary butterfly (Melitaea athalia) in woodland in England, for example, depends on the creation of woodland clearings by coppicing (rotational cutting). We have developed a simulation model to assist in the conservation of such populations, called MANAGE. We have parameterised the model for the M. athalia population in the Blean Woods in Kent, and used it to answer several management questions. We find that: (1) simulations predict that the observed rates of coppicing will not be enough to meet existing conservation (Biodiversity Action Plan) targets, except when the most generous modelling assumptions are made; (2) the greatest uncertainty in the model outcome arises from uncertainty in the colonisation parameters; (3) in the worst case scenario (using the most pessimistic model assumptions), a population would require 2.3% of the Blean Woods to be coppiced each year, which is around double the currently-observed rate; (4) the four management units of the Blean where coppicing is practised are not independent metapopulations– they support each other; and (5) to sustain a population in a smaller landscape would require less coppicing overall, but more as a percentage of the landscape. This modelling approach may prove useful in the development of conservation management plans for other species that inhabit successional habitats.     

Assessing habitat use of the endangered marine mollusc Patella ferruginea (Gastropoda, Patellidae) in northern Africa: preliminary results and implications for conservation

The limpet Patella ferruginea Gmelin, 1791, endemic to the Mediterranean, is the most endangered marine species on the list of the European Council Directive 92/43/EEC on the Conservation of Natural Habitat of Wild Fauna and Flora (1992). Its Mediterranean range has progressively contracted to a few restricted areas and the species is now threatened with extinction. Seventeen stations were sampled along the littoral zone on the coast of Ceuta, North Africa, for quantifying environmental factors (water movement, siltation and suspended solids), and 70 transects were selected for P. ferruginea sampling. The study revealed the presence of a well-established population of P. ferruginea with values of density and size of 0.67 individuals m⁻¹ ±0.96 and 48.94 mm±11.61 respectively (mean±standard error of mean). The biggest densities of P. ferruginea were found inside the harbour of Ceuta. The limpets were more abundant on artificial harbour stones than on natural rocky shores, and the areas under the highest human pressure were characterised by the lowest densities and the smallest specimens probably due mainly to the predation for food and fishing. Human pressure is probably the main contributing factor to the currently endangered status of P. ferruginea. Programmes of environmental education to avoid its collection for fishing, food or for fun as decorative objects should be conducted, and further experimental studies dealing with the reproductive biology of this species are needed to properly assess the future programmes of conservation.     

Evidence of rapid evolution and incipient speciation in Vicia sativa species complex based on nuclear and organellar RFLPs and PCR analysis

Seventy three accessions of the sevenVicia species belonging to Sativa speciescomplex were screened for nuclear and organellar restriction fragmentlength polymorphic (RFLP), and random amplified polymorphicDNA (RAPD) markers. Total genomic DNAs of 73 accessions wasrestricted with three enzymes, and the restriction fragments werehybridized to the wheat rDNA probe pTa71 (containing 18S, 5.8Sand 25S rDNA genes, and spacers), and faba bean probes Ver6-5 (entire intergenic spacer flanked by small part of25S and 18S fragments) and Ver 18-6 (part of thecoding region of the gene and internal transcribed spacers). InXbaI digests, 16 repeat unit length classes in24 combinations were identified. Digestion withEcoRI and DraI gave2–4 and 1–3 fragments, respectively, with detectablehybridization to the probes, indicating the existence of internalXbaI sites. All the accessions produced 3.5 EcoRI fragment arising fromcoding region of the repeat unit. Four hundred and eighteen RAPDmarkers among 45 accessions were identified with 14 arbitrary10-base primers. The percentage of polymorphic bands withinspecies ranged from 20 in V.angustifolia to 98% inV. nigra. Both RFLP andRAPD markers were unable to assess the relationships betweenaccessions within species as there was often much closer resemblancesbetween certain accessions of different species rather than betweenaccessions within each taxon. This analysis supports the view basedon morphological, cytogenetical and crossability data that it is notpossible to classify Sativa species complex into a small finitenumber of taxa which are clearly circumscribed, and that the complexrepresents a unique case of rapid evolution and incipient speciation.A study of chloroplast and mitochondrial RFLPs was undertaken toanalyze phylogeny through maternal lineage. Chloroplast DNArestriction fragment patterns, using 13 restriction endonucleases,revealed 92.6 to 99% homology between the seven species.Twelve enzyme-probe combinations yielded identical fragmentpatterns for all the seven species. The molecular sizes of thechloroplast DNAs obtained were similar (121.5–123.5), indicating that they had all lost one of theinverted repeats. Total DNAs digested with three restriction enzymesand hybridized to six heterologous probes of mitochondrial originyielded monomorphic bands in five enzyme—probe combinationsacross all the 73 accessions. In other combinations as well,40–66 accessions yielded monomorphic profiles. The smallvariation in the remaining accessions was not species-specificsince the same profiles were present in more than one species. Theseresults i) strongly suggest that the seven species within thecomplex share a common ancestor, or direct lineage and, ii)indicate that these species should be relegated to a rank, perhaps ofsubspecies, within V.sativa species complex.     

Seasonal movements in the Sumatran orangutan (Pongo pygmaeus abelii) and consequences for conservation

Preservation of orangutan habitat can only be effective when their range requirements are taken into consideration. Here, the effect of the variation in fruit supply at different altitudes on the seasonal movements of orangutans is investigated. Transects were surveyed every 2 months from 1998 to 2000, at different altitudinal zones in the larger Ketambe area, Indonesia. The density of orangutan and sources of ripe fruit with soft pulp were determined along these transects. Both orangutan density and the availability of fruit varied considerably throughout the survey period at different altitudinal zones. The peaks in fruit production at different altitudes occurred in successive periods. For each altitudinal zone a significant correlation was found between orangutan density and the number of fruit sources, which shows that orangutans follow the production of fruit between these altitudinal zones within the boundaries of their home range. Orangutans with core areas in intermediate and highland areas depend seasonally on fruit production of lowland areas, and vice versa. Thus, conservation of large tracts of primary forest with a range of different altitudes is necessary to preserve the remaining orangutan population.     

Using DNA from museum specimens to preserve the integrity of evolutionarily significant unit boundaries in threatened species

Use of DNA from museum samples is a powerful tool to directly establish historical ESU boundaries in areas where populations of a species have been extirpated. The brush-tailed rock-wallaby (Petrogale penicillata) has suffered extensive reductions in range and population size since European settlement in Australia. Populations of this species have been grouped into three putative evolutionarily significant units (ESUs) which were likely once contiguous along the south-east coast of Australia. However, there is currently a gap of ∼320 km between extant populations of the southern and central ESUs. Conservation plans for the brush-tailed rock-wallaby include re-introductions of animals to locations within their former range. In order to preserve the historic geographic integrity of the genetic lineages within the species, it is necessary to map the boundary between the southern ESU and central ESU to allow more informed management decisions about which lineages should be used to re-stock specific geographic locations. We have extracted DNA from samples from museum specimens that come from locations between the southernmost extant colony of the central ESU and the remaining wild colony of the southern ESU. We sequenced a 177 bp interval of the left domain of the mitochondrial DNA control region and used phylogenetic analysis to group obtained sequences with previously published sequences belonging to the three ESUs. We have extended the range of the central ESU southwards and the range of the southern ESU northwards such that the gap between the ESUs is now approximately 160 km. We recommend that, where suitable historical museum collections exist, this technique be incorporated into re-introduction plans for other threatened species.     

RFLP analysis of mitochondrial DNA in eggplant and related Solanum species

RFLP analysis of mitochondrial DNA (mtDNA) was performed by the Southern hybridization method using total DNA extracted from eggplant, Solanum melongena L., and six related Solanum species, S. surattense Burm. (i.e. S. virginianum L.), S. torvum Swartz, S. gilo Raddi (i.e. S. aethiopicum), S. integrifolium Poir. (i.e. S. aethiopicum), S. indicum auct. non L. (i.e. S. violaceum Ort.) and S. sanitwongsei Craib. Forty-one fragments were detected by the analysis using 12 combinations of four restriction enzymes and three probes of mtDNA clones from rice. Thirty-four out of the 41 fragments were polymorphic among the species, whereas the other seven were monomorphic. This RFLP analysis of mtDNA is demonstrated to be appropriate for assessing phylogenetic relationships in eggplant and related Solanum species at the interspecific level.     

Protected wading bird species threaten relict centenarian cork oaks in a Mediterranean Biosphere Reserve: A conservation management conflict

Conservation management conflicts frequently arise when an overpopulation of a protected organism has negative effects on other valuable elements in the same ecosystem. We studied the interactions between a colony of protected tree-nesting wading birds and a remnant population of centenarian cork oaks that was part of the formerly dominant forests in the Doñana Biological Reserve (SW Spain). A significant increase in the tree mortality rates has been recorded in areas that are yearly influenced by the bird colony.We analysed a cohort of surviving trees using a gradient of nesting bird influence. Tree-nesting history, bird isotopic signature (δ¹⁵N), tree health-related parameters (defoliation, δ¹³C and leaf surface coverage by faeces) and several soil variables were evaluated. Bird influence was related to increased soil salinity. This increase correlated to increased water-use efficiency for the leaves and to crown defoliation, suggesting that the heavily occupied trees are under higher stress and in poorer health condition than the unoccupied ones. We tested structural equations models (SEM) that were based on hypothesised bird effects on the health of the trees. Soil-mediated effects of the nesting birds best explained the symptoms of the declining health of the trees, whereas the percent of leaves’ surface that was covered by faeces did not improve the fitted SEM model.For the reserve’s managers, a challenging trade-off exists between preserving the relict trees, which have a high genetic diversity and a key ecological role in these savannah-like ecosystems, and maintaining the current nesting area for these protected, but expanding, wading birds.     

Capturing genetic diversity of wild populations for <Emphasis Type="Italic">ex situ</Emphasis> conservation: Texas wild rice (<Emphasis Type="Italic">Zizania texana</Emphasis>) as a model

Genebanks complement other conservation programs because they preserve genetic diversity needed for future breeding and restoration. We evaluated efficiency of capturing genetic diversity, using endangered Zizania texana (Texas wild rice) as a model for plants with recalcitrant seeds. This perennial aquatic grass is restricted to 4 km of the San Marcos River in Texas. An early conservation collection included plants from stands throughout the river, based on the assumption stands would be unique genotypes. Using microsatellite markers, we found that genetic diversity was concentrated in five of 15 large, demographically stable stands; 96 stands smaller than 2 m² contributed no unique alleles. High heterozygosity and few duplicate genotypes suggested that sexual reproduction occurs more often than presumed. Simulations of stratified sampling of large stands captured all alleles in only 45 individuals, while random sampling along the river captured much less diversity. The early conservation collection captured as much diversity as expected from random sampling. Texas wild rice stands resemble a mainland-island metapopulation; our analyses suggest that stratified sampling maximizes genetic diversity for this population dynamic. Demographic and genetic information is important for validating the design of efficient ex situ collections and guiding in situ conservation.     

Disturbance to a foraging seabird by sea-based tourism: Implications for reserve management in marine protected areas

The provision of recreational opportunities is one of the important human goals of marine protected areas. However, as levels of recreational use increase, human disturbance is likely to cause significant detrimental effects upon wildlife. Here we evaluate the best managing options to mitigate the impact of sea-based tourism on the foraging activity of an endangered population of European shags, Phalacrocorax aristotelis, in a coastal marine protected area (Cíes islands, north-western Iberia). Boat disturbance elicited a characteristic avoidance behavior that resulted in a substantial reduction in foraging activity as levels of boat use increased. Moreover, boats excluded shags from the best feeding areas, resulting in higher densities of foragers in areas of little boat traffic. We used a behavioral model to explore the effects of managing strategies aimed at reducing the impact of boats on the foraging activity of shags. Our model suggested that in low boat disturbance scenarios limiting the number of boats using the reserve would be a better management option than habitat protection (i.e. the establishment of set-aside areas free of boat traffic). On the contrary, when boat disturbance levels are high the protection of habitat is recommendable, even if spatial variation in habitat quality is unknown or poorly assessed. Our study stresses the point that management strategies to minimize disturbance to foraging seabirds may depend on the spatial overlap between sea-based recreational activities and foraging seabirds and the spatial variation in marine habitat quality for seabirds.     

Exploring genetic diversity and potential novel disease resistance genes in a collection of rice (<Emphasis Type="Italic">Oryza</Emphasis> spp.) wild relatives

Wild relatives of rice (Oryza spp.) are an important source of novel resistance (R-)genes for rice improvement. Rice sheath blight, caused by Rhizotonia solani, and leaf blast, caused by Magnaportha oryzae, are major fungal diseases of rice worldwide. To identify novel R-genes, a group of Oryza spp. accessions represented by O. alta, O. australiensis, O. barthii, O. glaberrima, O. glumaepatula, O. latifolia, O. meridionolis, O. nivara, O. officinalis, and O. rufipogon, were evaluated for their reaction to leaf blast and sheath blight disease, and genotyped with 176 microsatellite (SSR) markers. Selected rice (O. sativa) accessions were included as reference. Cluster analysis performed with PowerMarker software using Rogers genetic distance and UPGMA, revealed most Oryza spp. accessions clustered with the same species or a closely related Oryza spp. Only a few Oryza spp. accessions grouped with the O. sativa accessions included as a reference. Analysis of this genotypic data in the software Structure revealed that the Oryza spp. accessions were assigned into eight different subpopulations and fit well into eight different backgrounds. Marker-trait associations between the SSR markers and disease reactions to blast and sheath blight were ascertained using the software TASSEL. Associations with blast disease were identified in ten different chromosomal regions and five of the ten were not located near known blast R-genes. Three associations were discovered with sheath blight disease and one was not near previously reported sheath blight QTL. These newly identified regions may represent novel R-genes that will be the basis future fine mapping studies. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Observations on the geographic distribution, ecology and conservation status of several Phaseolus bean species in Costa Rica

Interest in bean genetic resources of Central America has resumed because of disease pressures (e.g., web blight, BGMV) and limitations of current bean varieties. As most of the diversity in landraces has been explored, focus is now on the exploration of wild forms of the primary gene pool and wild species of the secondary gene pool. A germplasm collection was carried out in the field and resulted in the collection of 29 wild populations for six Phaseolus species; it complemented field work done in 1987. Nine more populations were found for P. costaricensis, 10 for wild P. lunatus, one for P. oligospermus, one for P. tuerckheimii, four for wild P. vulgaris and four for P. xanthotrichus. Ninety-three herbarium voucher specimens were collected for 19 populations of the six species (deposited at CR). These results confirm the presence of wild P. vulgaris on both slopes of the central valley of Costa Rica, namely in the life zones bh-MB and bmh-P, and of P. costaricensis in the life zone bmh-MB. These life zones of limited range in Costa Rica have been heavily modified, thus fully justifying the germplasm collection for ex situ conservation. For both species the range of distribution in Costa Rica has been almost completely sampled. The life characteristics of each species that are relevant for their conservation in situ are briefly reviewed. Distribution ranges of each wild bean species are compared with the present extension of national parks, protected areas and fauna/flora sanctuaries, and suggestions for expanding such protected areas are made.     

Increased genetic differentiation in house sparrows after a strong population decline: From panmixia towards structure in a common bird

A drastic decline in abundance prompts conservation measures, even though a species may still be common, partly because such a decline may be associated with loss of genetic variability. Longitudinal evidence (i.e. repeated measures across time) for loss of genetic diversity is scarce and mostly concerns organisms that have experienced a severe bottleneck. Here, we study the house sparrow in Finland, where a strong (50–86%) reduction in abundance occurred in four decades, starting earlier and resulting steeper decline in the south than in the north. Based on thirteen polymorphic microsatellites, we compared 12 Finnish populations both prior (mid-1980s) and after (2009) the major population decline. There was no evidence of bottlenecks and only little loss of genetic variation, but we found a significant threefold increase in genetic differentiation (F_ST) across the populations. This may reflect a non-equilibrium situation between the rates of change in the genetic diversity and differentiation and indicate future loss of genetic diversity. Our findings indicate that a strong decline in population size in a relatively common species still leaves a noticeable population-genetic imprint and warrants conservation concern.     

Genetic diversity changes and relationships in spring barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) germplasm of Nordic and Baltic areas as shown by SSR markers

To examine changes in the level of and pattern in variability in 197 Nordic and Baltic spring barley cultivars over time we used 21 mapped barley simple sequence repeats (SSRs). A total number of 191 alleles were found from 22 SSR loci. The number of alleles per locus ranged from 2 to 23, with average of 8.63 107 alleles were rare (frequency <0.05) among the cultivars and only one allele was frequently observed (frequency >0.95). The gene diversity between loci in Nordic and Baltic material varied between 0.033 and 0.891. Average gene diversity was 0.623. The SSR data separated two-rowed and six-rowed cultivars. According to analysis of molecular variance (AMOVA) differentiation in two-rowed vs six-rowed accounted for 23.6% of the total variation. Overall no significant decrease of average gene diversity over time could be found. However, differences were observed when spring barleys from northern (north of ∼58°) and southern (south of ∼58°) parts of the Nordic and Baltic area were compared. For the southern ecogeographical region significant decrease of genetic diversity was observed in the middle of the 20th century, whereas no significant changes in the northern part were found. We found larger differentiation between modern and old cultivars in the South compared to the ones in North parts of the region. The magnitude of changes in genetic diversity differed also with the country of origin. Danish cultivars had a significant decrease in diversity in the middle of century, whereas changes in Finland, Norway and Sweden were not significant.     

Case studies on breeding systems and its consequences for germplasm conservation: 3. Electrophoretic mobility of phaseolins in wild populations of Lima beans (Phaseolus lunatus L.) in the Central Valley of Costa Rica

We studied the variation in the electrophoretic mobility of phaseolins of 202 individual seeds from thirty-eight wild populations of Lima beans (Phaseolus lunatus) in the Central Valley of Costa Rica. We found four main polypeptides or banding regions with molecular weights which ranged from 21.5 to 31 kDaltons. Two of these peptides were polymorphic, and their combination resulted in four distinct genotypes. The frequency of the different genotypes varies among populations, but two of them, namely B¹¹C¹¹, B²²C²², were found in most of the populations studied (37 out of 38 populations examined). Overall, there was a lack of heterozygotes among the individuals examined, which strongly suggests that there is gametic disequilibrium for the encoding regions involved in the synthesis of these polypeptides. When we arranged the populations into eight groups according to their proximity and phenology, we found that the distribution of the peptides was also variable among them. The possible association between the distribution of the patterns of electrophoretic mobility observed and climatic factors, such as mean annual rainfall, mean annual temperature and mean annual relative humidity is discussed.