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  • Author: Tomáš Koutecký x
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ABSTRACT

This paper presents an evaluation of full-area floristic mapping of floodplain forest in Tvrdonice forest district (Židlochovice Forest Enterprise) based on a single forest stand inventory. The study area encompasses 2,200 ha of forests, where 769 segments were inventoried, and 46,886 single records about presence of vascular plant species were catalogued. We found 612 species (incl. subspecies and hybrids), out of which 514 were herbs, 98 were woody plants, 113 were endangered species and 170 were adventive species. The average area of a segment is 2.86 ha. The mean number of species per segment is 60.97 in a range of 4-151.

Abstract

This paper presents an evaluation of full-area floristic investigation of floodplain forests in Soutok forest district (Židlochovice Forest State Enterprise) based on an individual forest stand inventory. The study area encompasses 5103 ha of forests, where 1186 segments were inventoried, and 71 223 single records about presence of vascular plant species were done. We found 761 taxa (species, subspecies and hybrids), out of which 655 were herbs, 106 woody plants, 156 were endangered species and 177 adventive species. The average area of a segment was 4.3 ha. The mean number of species per segment was 64.42 in a range of 4–180.

Abstract

Between 2010 and 2011 a field survey dedicated to Dracaena cinnabari (DC) population was conducted in Firmihin, Socotra Island (Yemen). It’s main goal was to collect data that would make it possible to unbiasedly estimate main characteristics of the local DC population. Our motivation was to provide reliable information to support decision-making processes as well as other research activities. At the same time we were not aware of a survey which could provide this kind of statistical-sound estimates for the whole population covering an area of almost 700 ha.

This article describes how the survey has been planned and carried out in practice. In addition, we also provide a set of preliminary estimates of the main DC population figures - totals and per hectare densities of stems, overall and partitioned according to predicted crown age. Among estimated parameters there are also mean crown age and proportions of predefined age classes on the total number of living DC stems. These estimates provide an explicit information on age structure of the whole DC population in Firmihin.

Although we collected data on more than one hundred randomly located plots, the reported accuracy of our estimates is still rather limiting. We discuss several possibilities to obtain more accurate results or at least to approach the supposedly lower true variance that can’t be calculated by approximate techniques applied here.

The design and concept of our survey makes it possible to evaluate changes over time on stem by stem bases and to generalize these stem-level details to the whole population. Mortality, regeneration and even change of population’s mean crown age can be estimated from a future repeated survey, which would be extremely useful to draw firm conclusions about the dynamic of the whole DC population in Firmihin.