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Population dynamics of a predator-prey system is usually simulated by the classical Lotka-Volterra models, which were successfully applied to the population dynamics of snowshoe hare and lynx and many other predator-prey systems. Attempts were made to apply them also to insect predator-prey systems, but in terms of biological control, they did not reveal the features of the predators that control the abundance of their prey. The most conspicuous example of failure of Lotka-Volterra models applied to insect predator-prey systems are ladybird-aphid systems, in which these models usually fail to fit empirical data. Because of their practical importance and because they are very well studied, we have chosen aphid-ladybird systems as a model. We summarize the results published on various aspects of the population dynamics of aphid-ladybird systems and present them in the context of empirical data. Using new data, we more closely specify the existing metapopulation model of aphid-ladybird interactions. Based on the arguments presented here, we conclude that the ladybird-aphid case can be generalized to insect (and maybe even other) predator-prey systems, where the ratio of the generation times of the predator to that of the prey (GTR) is large. In such systems, the main selection pressure on predators is choosing the best strategy to maximize survival of their offspring, rather than on maximization of the amount of prey eaten. Thus voracity, which is the main determinant of population dynamics in Lotka-Volterra models, loses its role and is replaced by optimization of the choice of oviposition sites in systems with large GTRs.

The natural environment has been significantly altered by human activity over the past few decades. There is evidence we are now experiencing the sixth mass extinction, as many species of plants and animals are declining in abundance. We focused on the Orchidaceae because this plant family has experienced one of the biggest reductions in distribution. We investigated patterns in species richness and distribution of orchids, the rate and causes of their decrease and extinction, and factors influencing their occurrence in the Czech Republic and Greece. The key findings are: (i) Method of pollination and type of rooting system are associated with their distributions and they are different in the two countries. We assume that these differences might be due to the difference in the orography, distribution of suitable habitats and types of bedrock in these two countries. (ii) The greatest reduction in distribution was recorded for critically endangered taxa of orchids. The number of sites suitable for orchids in the Czech Republic declined by 8–92%. The most threatened orchid species are Spiranthes spiralis, Anacamptis palustris, Epipogium aphyllum and Goodyera repens. The distribution of orchids in the Czech Republic is mainly determined by the distribution of their habitats. (iii) The most important factor affecting the distribution of Czech orchids in South Bohemia is land cover. And the most important types of habitats (types in KVES) are oak and oak-hornbeam forests and agricultural meadows. Based on this information, it should be possible to improve the management that is crucial for maintaining orchid localities.

One of the key goals of conservation biology is to determine what causes declines in biodiversity and suggest ways of stopping or slowing them down. Studies on the temporal changes in the distributions of species provide critical information on temporal trends in local extinctions and information on what causes these changes. This is especially true for endangered groups of plants, such as orchids. Here we analysed changes in the distributions of orchids in the Czech Republic over three time periods when the agricultural practices differed. Orchids were divided into two groups based on whether they provide nectar to their pollinators. Moreover, we determined the effect of three different spatial resolutions on the interpretation of the results. Many species in the Czech orchid flora have become rarer over time and four became extinct. These changes are directly associated with changes in the agricultural practices in the Czech Republic that started in the 1950s, which especially resulted in the abandonment of traditional management. Mosaics of small fields were converted into huge fields and the application of artificial fertilizers increased dramatically, both of which resulted in loss of natural habitats and decline in many species of orchids - both nectariferous and nectarless species. Our results are important for conservation and are aimed at preventing further decline in orchid sites and recovery of orchid populations.

We are experiencing climate warming that is likely to affect all regions worldwide, although in a different manner, when its consequences (e.g. increase of temperature, lower seasonality, lower environmental stochasticity) are considered. Thus, our prediction of how global change will affect distribution and survival of species can be estimated by using our knowledge, how species richness and distribution is related with latitude and elevation. We used 193 terrestrial orchid species and subspecies as an example and we classified them according to their root system. This trait represents the evolution of strategies for underground storage of resources and resource acquisition as well as a characteristics that can be described as a life history trait. Classification of orchid life history traits that focus on belowground strategies has never been examined in a macroecological study. We then explored the associations between species richness, mean niche breadth and mean distribution on one hand and selected predictors on the other hand, using regression techniques for all orchids, and then for their subsets with different root systems. The predictive power, as well as the significance of the predictors, was also tested using polynomial second order generalized linear models. Species richness for the three belowground strategies was significantly affected by the predictors, whereas their mean niche breadth and mean distribution were largely dependent on their evolutionary history. The correlations of mean niche breadth and mean distribution with maximum elevation, latitude and longitude were significant for all orchid taxa and their subsets. All the variables together accounted for almost 50% or more of the variance in each of the subsets. The maximum elevation was the most significant factor for rhizomatous and intermediate orchids, whereas minimum temperature in the coldest month was highly significant for the tuberous orchids. Spatial distribution of Greek orchids is associated with a combination of elevation, latitude and climate. The distributions of rhizomatous and intermediate orchids are mainly associated with the orographic configuration of Greece, whereas the tuberous orchids are widely distributed in the southern, central and north-western areas of Greece, where most of them are limited by the harsh winter climate.

Species distribution models are a useful tool and are now often used in many branches of biology, especially when dealing with threatened organisms. In combination with GIS techniques, these models are especially important and valuable for predicting the occurrence of rare species, for example orchids. Orchids are an endangered plant group, protected worldwide. Questions about their conservation are therefore highly discussed, but not all factors affecting their survival and distribution are known. Here we present an example of using SDMs for analysing orchid species occurrence data from the Jeseniky Mountains in the Czech Republic. Our data were analysed using the MaxEnt program, which produces species distribution maps and thus allows the prediction of the potential occurrence of orchids at yet unknown localities. This program also determines the environmental factors affecting species distribution. This is important for the better protection of orchids, because only by knowing these factors can new localities be found or the management plans that are crucial for maintaining orchid localities be improved. We studied the most abundant orchid species in the given region. We determined the most important factors affecting their occurrence and also areas, where new sites are most likely to be discovered and depicted them in potential distribution maps. This approach can help in finding new localities of orchids and in understanding, which environmental factors influence the occurrence of endangered orchids.

Decline in wet grasslands, which in the past resulted particularly from the intensification of agriculture, was accompanied by the loss of a lot of populations of organisms, including protected and endangered species of plants and animals associated with these habitats e.g. terrestrial orchids. The survival of populations of many species of European orchids is strongly dependent on appropriate site management, especially regular mowing or grazing. In addition, humans can negatively affect the persistence of orchid populations in various ways, such as conversion of orchid meadows into building areas, dams, roads etc. or the intensive use of fertilizers and contamination of areas by fertilisers from nearby fields. Comparison of historical data with the present distribution of orchids can reveal a lot about the main reasons for the decline in this endangered group of plants. Here we present an extensive study of the persistence of 192 historical orchid sites in South Bohemia, with particular reference to the 5 commonest species of orchids, Anacamptis morio, Dactylorhiza majalis, Epipactis helleborine, Epipactis palustris and Platanthera bifolia. We show that the most abundant species at the sites studied was Dactylorhiza majalis. E. palustris, A. morio and P. bifolia are currently not present at any of the historical localities for these species. Considering more recent history, the situation regarding orchid localities in South Bohemia is not critical, but the fate of these species should be closely monitored. The majority of this loss is due to the cessation of mowing of the sites. Thus more attention should be paid to the management of the existing sites. During this study, some new sites were discovered.