Search Results

1 - 4 of 4 items :

  • Author: Jan Šebesta x
  • Geosciences, other x
Clear All Modify Search

Vascular Plants Distribution as a Tool for Adaptive Forest Management of Floodplain Forests in the Dyje River Basin

The study is based on a full floristic inventory of floodplain forests in South Moravia along the upper part of the Dyje River (Forest district Valtice). The study area is located in the Dolní Morava Biosphere Reserve and includes several Sites of Community Importance within Natura 2000. The aim of the inventory was to analyze diversity of herb and woody species occuring in the study area, including both native protected and threatened species, and invasive species. The study area was divided into segments. A segment represented the smallest unit of spatial forest division - "forest stand part". The species were recorded into a special scratch-list. Altogether, 656 plant species were found. The floristic database has been integrated with GIS. Maps of distribution of selected plant species or groups of plants were produced. On the basis of geographical visualization of the above mentioned results we identified areas with a high diversity of all species and endangered species. The results may be used as a base for adaptive forest and environmental management.

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.