Malle Leht

• PhD
• Senior Researcher at Estonian University of Life Sciences

Questions Long‐term fragmentation and land use in Europe have created a landscape pattern where small forest patches are embedded among agricultural landscapes. These small forest patches can be one of the few habitats left to maintain the species richness and ecosystem functions within intensively managed agroecosystems. We ask, which factors dete...

The studies on clonal plant populations indicate that the proportion between clonal and sexual reproduction may be highly variable, depending on the biological characteristics of species and the ecological conditions of habitats. We focused on the genotypic diversity of Trifolium alpestre populations in Estonia. We assayed the genetic diversity, sp...

We studied the occurrence of the crop-to-wild introgressive hybridization in the Medicago sativa-falcata complex in the distribution area of the native M. sativa ssp. falcata (hereafter falcata) in western and northern Estonia. Flower colour and pod shape were used as the diagnostic genetic characters to assess the extent of hybridization from cult...

The morphological and chromosomal variation of Medicago falcata L. was studied in 47 populations in Estonia to ascertain differences between two chromosome races: diploids (2n=16) and tetraploids (2n=32). The results showed that both chromosome races are growing in Estonia but they are not well distinguishable on the basis of morphological characte...

Omnivores exploit numerous sources of protein and other nutrients throughout the year, and meat is generally considered a high-quality resource. However, it is unknown if there is any general association between latitude and carnivorous behavior in omnivorous mammals. We examined the relative importance of meat and other dietary components, includi...

The phylogenetic relationships among 67 Vicia species from Eurasia were studied in relation to Trifolium montanum on the basis of 91 morphological characters. The characters were coded as multistate, 17 were treated as ordered. In subgenus Vicia, V. sepium and V. oroboides form a separate taxon, section Sepium, into which V. grandiflora should be i...

The genus Lathyrus is supported as a well defined genus not subdivisible into subgenera. The results of the present analysis clearly support sections Cicerula and Lathyrus s.str. with L. hirsutus in a monospecific clade, but not separation of section Gorgonia. Section Pratensis is not warranted and the taxa should belong to section Aphaca. Lathyrus...

Previous studies of vetch species belonging to sections Hypechusa, Narbonensis and Peregrinae have revealed controversies and open questions that deserve revisiting with the use of contemporary approaches. The paper extends the previous work of Leht and Jaaska (2002) by describing variation of 16 isozymes and 86 morphological characters among 17 Vi...

Variation of 89 multistate morphological characters in 44 species of Vicia subgen. Cracca was investigated with cladistic and phenetic methods using Lathyrus sylvestris and Pisum elatius as outgroups. The subgenus appears monophyletic; the Ervum group is supported as a section. Sections Vicilla and Cassubicae appear monophyletic when V. amoena is m...

180 specimens of P. erecta, 58 of P. reptans, 49 of P. anglica and 19 of P. x italica were studied phenetically using 19 macromorphological characters. As P. erecta and P. reptans are quite common in Estonia, while P. anglica is absent from here, the occurrence of P. x italica in Estonia points to its possible origin from the hybridization of the f...

 Variation of 80 multistate morphological characters and isozymes encoded by 13 loci among 23 vetch species of the type subgenus of the genus Vicia in comparison with V. dumetorum, V. pisiformis and V. sylvatica of the subgenus Cracca is described and analyzed with cladistic parsimony and phenetic neighbour-joining methods by using two different wa...

On the basis of quantitative analysis of the vascular plant distribution maps for Estonia, we specified the list of rare species which occur in less than 5% of grid quadrangles, and studied the possible correlations between their rarity and habitat preference, distribution, and sensitivity to human impact. Rare species occur statistically more ofte...

Morphological variation of Saussurea esthonica Baer ex Rupr. and S. alpina (L.) DC. s. str. was studied with different multivariate methods. The most important characters supporting the clustering of the specimens into groups are the shoot hight and characters correlated to it, and hairiness of leaves, while the type of trichomes in both taxa is th...

Potentilla fruticosa L. (Rosaceae) was found to be a dioecious tetraploid (2n = 28) in all three Estonian and in the only Latvian native populations. According to this, it will be confirmed that Estonian and Latvian shrubby cinquefoils belong to P. fruticosa s. str. We believe that in Estonia P. fruticosa is a relic plant, not the naturalized speci...

Morphological variation ofPotentilla norvegica L.,P. heidenreichii Zimmeter andP. supina L. usually treated within the sectionRivales Wolf,P. recta L. (sect.Rectae Wolf),P. canescens Bess.,P. argentea L. s.l.,P. collina Wibel (sect.Argenteae Wolf) andP. goldbachii Rupr. (sect.Chrysanthae Wolf) was studied using multivariate statistical methods. Acc...

The morphological variation of four Baltic representatives of the genus Potentilla section Aurea–P. neumanniana, P. arenaria, P. subarenaria and P. crantzii was studied with multivariate methods. Altogether 41 characters were used. The most important characters for the phenetical classification are those of the epidermis: characters of stellate and...

Infraspecific variation of Estonian Potentilla erecta (L. ) Rausch. was studied with different morphometrical methods. Both P. erecta sap. erecta and ssp. strictissima (Zimm. ) A. J. Richards were identified with ssp. strictissima prevailing; however, several specimens are morphologically of an intermediate type. Representatives of the two taxa hav...

After floristic investigations in synanthropic habitats in 1978-1989, four species new for the Lithuanian flora were found: Potentilla bifurca, P. multifida, P. goldbachiii and P. longifolia. Information on the distribution of Potentilla heidenreichii, P. intermedia, P. norvegica and P. supina, which were very rare in Lithuania was considerably exp...