Search results for "Community Structure"
showing 10 items of 163 documents
Long-term changes in breeding bird community of a Primeval Temperate Forest: 45 years of Censuses in the Białowieża National Park (Poland)
2022
W pracy omówiono długoterminowe trendy zmian liczebności 30 leśnych, pospolitych ptaków lęgowych na 7 stałych powierzchniach próbnych w Białowieskim Parku Narodowym w latach 1975– 2019 (wschodnia Polska, dalej BPN, Fig. 1). Przeanalizowano zmiany w składzie ugrupowań ptaków lęgowych w trzech najważniejszych typach drzewostanów pierwotnych w BPN: łęgach (Fig. 2), grądach (Fig. 3) i borach (Fig. 4). Cenzusy kontynuowane w latach 2015–2019 z wykorzystaniem kombinowanej metody kartograficznej na siedmiu stałych powierzchniach próbnych w BPN, monitorowanych od 1975 r., w tym dwóch na skraju lasu i pięciu w jego wnętrzu wykazały gniazdowanie 69 gatunków ptaków. Najwięcej gatunków gniazdowało w łę…
Community-based method for extracting backbones
2022
Networks are an adequate representation for modeling and analyzing a great variety of complex systems. However, understanding networks with millions of nodes and billions of connections can be pretty challenging due to memory and time constraints. Therefore, selecting the relevant nodes and edges of these large-scale networks while preserving their core information is a major issue. In most cases, the so-called backbone extraction methods are based either on coarse-graining or filtering approaches. Coarse-graining techniques reduce the network size by gathering similar nodes into super-nodes, while filter-based methods eliminate nodes or edges according to a statistical property. In this wo…
Diversity and Community Structure of Opiinae (Hymenoptera: Braconidae) in the Forest Estate of Artikutza (Spain)
2011
ABSTRACT The present work analyses the diversity of Opiinae (Hymenoptera: Braconidae) in the forest of the Artikutza Estate, within the Natural Park, Penas de Aya, in the western Pyrenees. Specimens belonging to this subfamily were collected throughout two cycles and in two different habitats: mixed forest and beech forest. A total of 105 specimens, including 20 different species, were collected. Diversity and structure analysis indicated higher diversity for the beech forest habitat, although the community is composed of a few abundant species and many rare species. A relationship between the presence of Opiinae and an increase in temperature was also ascertained.
Global warming affect Collembola community: A long-term study
2006
Summary Long-term (1992–2002) effects of climate changes on soil Collembola in Scots pine Pinus sylvestris forests in North Vidzeme Biosphere Reserve (northern Latvia) are investigated. The study was carried out in three forest stands of different age, young (30–40 years), middle aged (50–70 years), and old (150–200 years). One hundred soil samples were collected within each sampling site once a year in autumn over a period of 11 years. In total, 66 species of Collembola were found. Species richness varied between 47 and 56 and density of Collembola from 7300 to 8300 ind m−2. A statistically significant increase in the sums of positive air temperatures (⩾4 °C) was recorded during the period…
Crop type and altitude are the main drivers of species composition of arable weed vegetation in Tajikistan
2015
Summary The influence of broad-scale environmental factors on the species composition of segetal weed communities in Tajikistan was investigated. The research was conducted throughout the country, analysing plots of root crops as well as cereals from all phytogeographical regions of Tajikistan, with the exception of the eastern Pamir. The study was based on 440 phytosociological relevees sampled between 2009 and 2013 and analysed using direct and indirect ordinations. A set of environmental variables was obtained for each plot: altitude, mean annual precipitation, mean annual temperature, pH, crop type, longitude, latitude and date of sampling (seasonality). Crop type was the major factor d…
Microfungal community structure in anthropogenic birch stands in central Finland
2002
We describe the soil microfungal communities in 30-year-old birch (Betula pendula Roth) stands planted either on former spruce forest soil (BS) or on former arable soil (BF) and compare these with the soil microfungal communities in spruce forests (S), arable fields (F) and old deciduous forests (D). Fungi were isolated from 0- to 3-cm and 3- to 6-cm samples collected in September 1997 and May 1998. Principal components analysis differentiated fungal communities in the S and BS sites from those in the other site types. The Morisita-Horn index of similarity indicated that fungal communities in the F and BF sites were less similar to those in the other site types. Fungal communities of the BS…
Riverine impacts on benthic biodiversity and functional traits: A comparison of two sub-Arctic fjords
2020
Abstract Climate change is leading to increases in freshwater discharge to coastal environments with implications for benthic community structure and functioning. Freshwater inputs create strong environmental gradients, which potentially affect the community structure of benthic infauna. In turn, changes in functional trait composition have the potential to affect the processing of terrestrially-derived nutrients and organic matter along the freshwater to marine continuum. We investigated the effects of riverine inputs on benthic community structure, functional traits, taxonomic and functional diversity, and utilization of terrestrial organic matter in two contrasting northern Norwegian fjo…
Community structure and the evolution of aposematic coloration
2002
Studies on the evolution of aposematic coloration (prey coloration advertising for unpalatability) have mainly focused on predator psychology in simplified single-prey species systems. We chose, instead, to model population dynamics on the community level. We studied the invasion by an aposematic phenotype in the presence and absence of another prey species. The single-prey and two-prey models differed in two major ways. First, with two prey species the invasion was possible only with a weak aposematic signal, whereas with a single prey species there was no such an upper limit for signal strength. Second, with a single prey species, increase of the aposematic phenotype always resulted in ra…
Temporal Distribution of Gastropods In Rocky Intertidal Area In North Manokwari, West Papua
2019
Gastropods is an important organism that commonly found inhabiting the rocky intertidal area. Distribution pattern of this species is influenced by various factors such as population history, microhabitat, predation and a complex interactions between oceanographic dynamics and ecological features. This study aims to compare the temporal distribution pattern of gastropods at two different rocky intertidal area. This research was conducted at the rocky intertidal area of Amban and Nuni, North Manokwari District, West Papua. Data collection was performed during the daylight and night in April and June 2012 using systematic sampling method. The results showed that both physical and chemical fac…
Effect of restoration on zooplankton community in a permanent interdunal pond
2013
Restoration projects in wetlands are becoming increasingly frequent to recover or to create new aquatic ecosystems, after the significant impact and high degradation they have undergone. In the present study, we focused on the changes in the zooplankton community in a permanent peridunal pond where a restoration was carried out in order to increase its surface as a main objective. For this purpose, the community was compared before and after the restoration (15 years before, the year after and between 3 and 6 years later). Significant changes in environmental variables were observed after pond restoration: chlorophyll a concentration decreased and dissolved oxygen increased. Substantial mod…