Successional Changes In Vegetation Research Articles

Annual Variation in Birds and Plants of a Tropical Second-Growth Woodland

We examined effects of successional changes in vegetation on bird species found in a young second-growth woodland in Costa Rica over a four-year period (1985-1988). Significant changes in vegetation structure and plant composition occurred: numbers of small (2-5 cm dbh) trees, woody shrubs, and lianas increased, as did canopy cover; herbaceous shrubs declined in abundance. Total numbers and species of plants producing flowers pollinated by hummingbirds or fruits eaten by birds did not change, but significant changes were noted in fruit production of individual plant species. Overall capture rates of birds in mist nets did not vary significantly among years but significant changes were noted for individual species. Several bird species characteristic of mature forest habitat first appeared in second-growth woodland during latter years of the study; other species, more dependent on early successional habitats, decreased in abundance or disappeared entirely from our study plot. Diets of some fruit-eating birds changed over time, apparently in response to changes in abundance of different fruit species. This study suggests that changes in plant and bird populations may be relatively rapid in tropical second-growth habitats. Such results have important implications for conservation; a range of successional stages may be necessary to support the full complement of bird species that can occur in a given area.

Demographic Profiles of Populations of Cotton Rats in a Continuum of Habitat Types

We examined temporal relationships between characteristics of populations of cotton rats ( Sigmodon hispidus ) and vegetative characteristics of habitats following secondary succession of post oak ( Quercus stellata )-blackjack ( Q. marilandica ) savannas in central Oklahoma. Successional changes in vegetation were induced on manipulated habitats by one of two herbicides (tebuthiuron, triclopyr) applied in 1983 and used in combination with or without annual prescribed burning during 1985 to 1988. Relative population density (animals caught per 100 trapnights) and percentage of reproductively active adult females (lactating or pregnant) were significantly greater on manipulated habitats dominated by monocots (grasses) than on habitats with monocots and dicots or undisturbed controls. Herbaceous dicots also influenced the density of cotton rats, especially in 1986; relative density peaked on all manipulated habitats following a peak in production of herbaceous dicots in 1985. Nutritional quality of herbaceous vegetation may have been enhanced by annual burning; relative densities and proportions of juveniles in the trapable population were higher in burned than in unburned habitats. This observation was most pronounced in 1986, when herbaceous dicots comprised a greater proportion of the primary production, than in 1987 or 1988.

A “Marvelous Cosmopolitan Preserve”: The Dunes, Chicago, and the Dynamic Ecology of Henry Cowles

One of the most influential research and teaching programs to emerge in the new science of ecology in the early twentieth century was that which developed at the University of Chicago under the direction of botanist Henry Chandler Cowles. Not a prolific writer, Cowles was nevertheless author of two of the seminal papers in American plant ecology. On the basis of those early contributions, as well as his considerable abilities as field guide, he was able to draw numerous students into Chicago’s new plant ecology program for both introductory and advanced work. No small part of the attraction of the program was Cowles’s ability to interpret successional changes in vegetation in terms that fitted in well with the forward-looking, reform-minded mood of the educated elite of the nation and the city of Chicago during the early decades of the century. Cowles’s favorite outdoor laboratory, the region of sand dunes along the Indiana shore of Lake Michigan, provided the ideal setting for his vivid telling and retelling of the story of the struggles and transformations of plant communities toward the establishment of the inevitable climax community. Both this dramatic tale of progressive change and the unusual diversity of species and communities at the dunes reflected qualities of Chicago itself, and Cowles interpreted these ecological phenomena in a manner that bore a striking resemblance to the frontier hypothesis of Frederick Jackson Turner.

A preliminary study of successional changes in vegetation and soil development on unamended fly ash (PFA) in southern England: P. J. A. Shaw, Journal of Applied Ecology, 29(3), 1992, pp 728–736

A preliminary study of successional changes in vegetation and soil development on unamended fly ash (PFA) in southern England: P. J. A. Shaw, Journal of Applied Ecology, 29(3), 1992, pp 728–736

A Preliminary Study of Successional Changes in Vegetation and Soil Development on Unamended Fly Ash (PFA) in Southern England

1. Vegetation cover and soil development were studied on abandoned PFA lagoons in the Lee Valley, southern England, covering an age range of 7-24 years. 2. The plant succession resembled that found on colliery spoil, with a mixed ruderal community leading to woodland dominated by birch (Betula spp.) and willow (Salix spp.). 3. The soil profile developed a humic surface horizon with little vertical mixing because decaying vegetable matter was not buried by earthworms. The thickness of this horizon correlated closely with development of other soil variables and with site age. 4. Multivariate analyses showed that soil development correlated more closely with site age than did the plant community composition

Variation in Coyote Diets Associated with Season and Successional Changes in Vegetation

Diets of coyotes (Canis latrans) on the Rob and Bessie Welder Wildlife Refuge (WWR) in south Texas were determined from analyses of scats collected during 1961-62, 1973-74, 1975-76, and 1978-79. Diets varied among years due to successional changes in vegetation and changes in prey abundance. Coyote diets also varied seasonally, reflecting changing abundances of a wide variety of food items, differential vulnerability of prey, effects of plant phenology, and weather conditions. J. WILDL. MANAGE. 5 1(2):273-277 Short-term studies have shown pronounced seasonal variation in coyote diets related to the availability of various foods (Gipson and Sealander 1976, Litvaitis and Shaw 1980, MacCracken and Hansen 1982, Van Vuren and Thompson 1982, Harrison and Harrison 1984). However, reports of coyote diets over long periods of time from the same area (e.g., Leopold and Krausman 1986) are scarce, and we are not aware of studies reporting variations in diets associated with successional changes in vegetation. In this paper we report on coyote diets on the WWR during 1961-62, 1973-74, 1975-76, and 1978-79, comparing feeding patterns among these periods and relating variations in diets to changes in vegetation and vertebrate prey populations. We thank the Rob and Bessie Welder Wildlife Foundation (WWF), Sinton, Texas and the Natl. Sci. Found. for funding this study. This paper is WWF Contrib. 302.

Carbon relations and competition between woody species in a Central European hedgerow : IV. Growth form and partitioning.

Growth of woody species has two components, one pertaining to increment of biomass, the other to the architectonic arrangement of dry matter in space. Only the combination of both components explained the competitive strength of species that dominate in different stages of a hedgerow succession in Central Europe. Biomass increment was measured using an empirical volumetric method, and plant architecture was investigated from branching patterns which determined the growth form of species. Assimilate partitioning was determined from total plant carbon gain and biomass increment in different above-ground plant parts. Those species with lower dry matter, nitrogen, and phosphorus costs for occupying and shading space during canopy development were the stronger competitors and replanced pioneers, even though their rate of CO2 uptake was low. Ecological implications of different partitioning patterns for the survival of a plant and for successional changes in vegetation are discussed.

The scientific basis of practical conservation: factors limiting the persistence of populations and communities of animals and plants

There are three main objectives to the management of habitats for conservation: (1) the modification of successional changes in vegetation and its associated fauna; (2) the increase of the biotic diversity, or richness of a habitat; and (3) the conservation of rare or endangered species. The success of each of these rests largely upon the identification and manipulation of those environmental factors currently limiting the populations and communities which are wanted. Examples will be given of research in progress showing how this can aid each of these conservation objectives. One cannot alter a habitat to encourage one species, or group of species, without this having repercussions on other parts of the flora and fauna. For this reason, there must be a clear understanding of the objectives to be achieved and research into the best way of achieving them, before conservation can be put on a firm scientific basis.