Reproductive Strategies in Herbaceous Plant Communities During Succession

Abstract

Reproductive strategies of herbaceous plants were analyzed in three successional communities. The communities were a 1—yr old—field, 10—yr old—field, and forest. Analyses included measurement of community—wide reproductive effort (reproductive dry wt/total dry wt) at 3—wk intervals throughout one growing season. Reproductive effort was highest in the 1—yr field. There was essentially no difference in reproductive effort between plants in the 10—yr old—field and forest communities; both exhibited relatively low reproductive effort. Reproduction in the 1—yr and 10—yr fields was highly synchronous; there was little synchrony of reproduction in the forests. This may indicate a more efficient utilization of resources throughout the growing season in the forest. Analyses also included measurement of numbers of seeds per plant produced by dominant species in each community. Number of seeds per plant in the 1—yr and 10—yr fields was relatively high, while number of seeds per plant was comparatively low in the forest. The ratio of root:total biomass increased with successional age, reflecting a proportionately larger expenditure of energy on competitive structures in the forest. Also, goldenrods, dominants in the 10—yr field, were found to possess 1 characteristic of an r—strategy (i.e., large number of small seeds) and a characteristic of a K—strategy (i.e., low reproductive effort). This apparent paradox was explained by relating these characteristics to the selective pressures that might produce them. In addition, the empirical data provide support for expanded concepts of reproductive strategies.

The effectiveness of asexual and sexual reproduction in clonal species Dianthus superbus L. in different site conditions – the consequences for population development

“…Gray (Ikegami et al 2004) and Iris sibirica L. (Kostrakiewicz 2007). Furthermore, presented findings stay in accordance with predictive models Newell and Tramer (1978), as well as Takada and Nakajima (1996). Above mentioned authors stated, that clonal growth should be dominant in stable habitats, while sexual reproduction prevails in sites with fluctuating environmental conditions and strong competition.…”

Life Histories and Demography of Shade‐tolerant Temperate Forest Herbs: A Review

“…Oxalis acetosella L. (Packbam, 1978) and Viola spp., tbe cbasmogamous flowers are generally present in tbe spring, tbe cleistogamous flowers being produced later in tbe summer. Altbougb many deciduous forest berbs flower in late sumnier (Newell and Tramer, 1978), none of tbese species bas been tbe subject of a life bistory study.…”

“…Tbe only generalization one can make with assurance is that the amount of energy devoted to sexual reproduction (i.e. flower and seed production) is usually less for forest herbs than for herbs of grasslands or early-successional habitats (Newell and Tramer, 1978;Abrahamson, 1979). It is impossible to judge whether species relying primarily on seeds for replacement devote more effort to sexual reproduction than do species that commonly reproduce vegetatively, because this information is not available.…”

Disturbance, Pollinator Predictability, and Pollination Success Among Costa Rican Cloud Forest Plants

“…Spatial variation in the efficacy ofanimal pollination (e.g., see Parrish andBazzaz 1979, Collins et al 1985), for example, is one of many possible causes for the consistent differences in phenotypic traits between plant populations occupying intensively disturbed habitats and those occupying less disturbed sites (e.g., see Baker 1959, 1965, 1974, Gadgil and Solbrig 1972, Cruden 1976, 1977, Jain 1976, Werner and Platt 1976, Abrahamson 1978, Newell and Tramer 1978, Oka 1983. Among plants occupying recently or intensely disturbed sites, obligate outbreeding, or breeding systems requiring animal pollination at all, occur less frequently than among plants of undisturbed sites (e.g., see Stebbins 1957, 1958, Baker 1959, 1965, Grant 1975, Cruden 1976, 1977, Jain 1976.…”