Relict Habitats Research Articles

K malakologické charakteristice mokřadů Kokořínska [Malacological characteristics of wetlands in the Kokořín Area

Two different types of molluscan communities from two wetland sites in the Protected Landscape Area of Kokořínsko (Central Bohemia) are described and analysed. The malacocoenosis from the seepage Pod Hvězdou consists of common wetland, catholic and woodland species without relict elements, whereas the Orchis meadow at Blatečky is characterized by endangered relict snails, such as Cochlicopa nitens, Euconulus alderi and both heliophilous Vertigo species – V. angustior and V. antivertigo as well as by the absence of the above woodland and catholic elements. For this reason the Blatečky meadow represents a relict habitat of high value from the viewpoint of nature conservancy.

K malakologické charakteristice mokřadů Kokořínska [Malacological characteristics of wetlands in the Kokořín Area

Two different types of molluscan communities from two wetland sites in the Protected Landscape Area of Kokořínsko (Central Bohemia) are described and analysed. The malacocoenosis from the seepage Pod Hvězdou consists of common wetland, catholic and woodland species without relict elements, whereas the Orchis meadow at Blatečky is characterized by endangered relict snails, such as Cochlicopa nitens, Euconulus alderi and both heliophilous Vertigo species – V. angustior and V. antivertigo as well as by the absence of the above woodland and catholic elements. For this reason the Blatečky meadow represents a relict habitat of high value from the viewpoint of nature conservancy.

The implication of past and present landscape patterns for biodiversity research: introduction and overview

Since its development in the early 1980s, the aim of landscape ecology is to understand both the effects of spatial patterns on ecological processes and the development of those spatial patterns. In Europe, human activities have had a pronounced long term role in shaping this heterogeneity so that Europe is now the most modified of any continent (Godron and Forman 1983). Therefore, research on how humans have shaped landscapes is of utmost importance (Burel and Baudry 1999). If changes following the World War II are a frequent topic, long term changes are also important (Berlung 1991) as they have, in interaction with the physical environment, selected the regional species pool. Indeed, present co-existence of species in the landscape is thought to be the end product of a series of long term responses between species requirements and environmental gradients of both natural and human origin (Huston 1994). Despite potential adverse effects, many long-term human disturbance regimes have promoted biodiversity. In western Europe, traditional ‘low intensity’ agriculture has often promoted high levels of diversity, or provided relict habitat for rare or threatened taxa (Green 1990). By analysing ecological patterns and functioning at large spatial and temporal scale, landscape ecology offers some of the most successful examples of the uptake of ecology in policy or management (Ormerod et al. 2002). If regional approaches are increasing (Suarez-Seoane et al. 2002), landscape studies of a lesser extent (few km2) are still dominant. One of the most important current areas in which the study of landscape patterns, past and present, offers a major path of research is in understanding the sustainable management of biodiversity. This was the theme of a meeting of landscape ecologists held in Rouen, France in October 2001. Our aim with this array of selected papers from the meeting is to share our outlook on current European trends and approaches to landscape ecology.

Riparian vegetation diversity along regulated rivers: contribution of novel and relict habitats

1. The creation and maintenance of spatial and temporal heterogeneity by rivers flowing through floodplain landscapes has been disrupted worldwide by dams and water diversions. Large reservoirs (novel ecosystems) now separate and isolate remnant floodplains (relict ecosystems). From above, these appear as a string of beads, with beads of different sizes and string connections of varying lengths.2. Numerous studies have documented or forecast sharp declines in riparian biodiversity in relict ecosystems downstream from dams. Concurrently, novel ecosystems containing species and communities of the former predam ecosystems have arisen along all regulated rivers. These result from the creation of new environments caused by upper reservoir sedimentation, tributary sedimentation and the formation of reservoir shorelines.3. The contribution of novel habitats to the overall biodiversity of regulated rivers has been poorly studied. Novel ecosystems may become relatively more important in supporting riverine biodiversity if relict ecosystems are not restored to predam levels. The Missouri River of the north‐central U.S.A. is used to illustrate existing conditions on a large, regulated river system with a mixture of relict and novel ecosystems.

Estimating the Viability of Ovenbird and Kentucky Warbler Populations in Forest Fragments

Breeding habitats for birds in deciduous forests of the eastern and central United States are becoming increasingly fragmented by human activities. Avian communities in small, isolated forest tracts are generally subsets of the communities present in larger forests (Blake & Karr 1987; Hayden et al. 1985); species that are intolerant of habitat reduction are frequently termed area-sensitive. Severe declines in songbird populations, particularly those of forest-interior-breeding neotropical migrants, have been linked to the destruction and fragmentation of natural habitats (Lynch & Whigham 1978; Robbins 1979; Whitcomb et al. 1981). Detailed studies of the dynamics and constitution of small populations in relict habitats are needed (Lande 1988). Data on the presence of species over a range of patch sizes of suitable habitat have been analyzed to estimate the patch size at which an area-sensitive species commonly occurs (Blake 1983; Diamond 1978; Galli et al. 1976), which is known as its minimum area requirement (Robbins 1979). However, tract sizes corresponding with incidence-curve inflection points (Diamond 1978) or areas of occurrence (Blake 1983; Galli et al. 1976) may fall in the range of marginal rather than preferred habitats for area-sensitive species. Forest fragments may represent marginal habitat for

Rich Fen Bryophytes in Missouri: Ecological Comments and Three State Records

Aneura pinguis (L.) Dum., Calliergonella cuspidata (Hedw.) Loeske, and Campylium stellatum (Hedw.) C. Jens. are reported new to Missouri from calcareousfens of the eastern Ozarks. Aneura occurs farther south in Arkansas and Oklahoma, but the Calliergonella and Campylium are disjunct and at the southernmost known limits of their ranges in the Midwest. It is probable that these fens in Missouri provide relict habitats for species that were more widespread in the lower Midwest during Pleistocene full glacial time. Calliergonella is documented from Alberta, Canada as well. Fens are grass-, sedge-, or reed-dominated, peat- forming ecosystems that develop under the influ- ence of mineral-rich ground water (Crum 1988). Like bogs, fens are systems in which productivity exceeds decomposition and hence peat, rich in or- ganic material, accumulates. Fen peat forms a sub- strate upon which unique assemblages of plants are found. These include a diversity ofbryophytes, from peat mosses of the genus Sphagnum that dominate in acidic poor fens to brown mosses, mostly of the families Amblystegiaceae and Brachytheciaceae, that dominate in alkaline, rich fens. Fens are most abundant in boreal landscapes that, in North Amer- ica, have been recently glaciated. As temperatures increase, decomposition rates increase (Damman 1979); therefore, farther south in temperate North America fens decrease in abundance. In the central Midwest, they form a minor component of the land- scape. Missouri fens are calcareous communities that occur mainly in the unglaciated Salem Plateau re- gion in the Ozarks of southeastern Missouri (Kurz

The Inheritance of Territory in Group-Breeding Birds

Recent advances in animal socioecology stress the importance of kinship and group living in the evolution of social behavior (see Wilson 1975). Although many animals exhibit a relatively simple social system in which individuals disperse and breed upon reaching maturity, among some higher vertebrate species certain individuals regularly delay breeding beyond normal physiological maturity and live for long periods in extended family groups. Group breeding, in which nonbreeding individuals help care for the young of a breeding pair, is now documented for a great variety of birds (Rowley 1976). Of special interest to evolutionary biologists is the question: Why do certain individuals seem to forfeit their own reproductive efforts to assist others with their breeding? Typical of the group breeders studied to date is close genetic relatedness between the helpers and the young they help raise (Brown 1974, Gaston 1976, Hardy 1976, MacRoberts and MacRoberts 1976, Maynard Smith and Ridpath 1972, Rowley 1965, Woolfenden 1975). Furthermore, the presence of helpers has been shown to increase the number of offspring produced by the resident breeders, who usually are parents of the helpers (Rowley 1965, Woolfenden 1975). Thus, by helping to raise kin, a nonbreeder may increase the representation of its own genes in the population without being a parent (Hamilton 1964, West Eberhardt 1975). This has led to the conclusion that kin selection underlies the evolution of helping behavior (Brown 1974, Wilson 1975). Our preliminary work with Florida scrub jays (Aphelocoma c. coerulescens), plus certain data available for other group-breeding birds, suggests the possibility of additional, more direct benefits to the helpers from delaying breeding and helping. Many group-breeding species studied to date occupy mature, often relict habitats, and show many characteristics of intense K-selection (sensu MacArthur and Wilson 1967; Brown 1974, 1975). Competition for space appears to be paramount among these characteristics. This observation, together with the data presented herein, leads us to hypothesize in this paper that, in certain species, remaining home and helping represents a strategy used by nonbreeders to inherit the space necessary for breeding.

Some Pselaphid Beetles With Boreal Affinities and their Distribution Along the Postglacial Fringe

Many species of relict boreal insects reside along the postglacial border in central and eastern United States in scattered series of sphagnum bogs. The distributional patterns of these insects are often influenced to a considerable extent by climatic factors and may reflect past climatic conditions, especially if the species involved are restricted by specific microclimatic requirements and are themselves incapable of active dispersal beyond these limits. Over 20 species of pselaphid beetles with boreal affinities are characteristic bog inhabitants. The range of each species is correlated with glacial processes and the contemporary distribution of bog plants. Included among the factors discussed affecting their distribution are glacial influences, ecological limits, and species dispersal potentials. None of the true bog pselaphids are known beyond the limits of Wisconsin glaciation, except for the Wisconsin driftless area and New Jersey breaches paralleled by bog plant distributions. The specificity of most species to these relict boreal habitats bespeaks their value as indicators of biotic displacement.