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We investigated the ability of an assemblage of animals and plants on rocky shores in southeastern Australia to resist and/or recover from repeated pulse disturbances in the form of trampling. Disturbances of four different intensities were applied experimentally over six summers, with no human access at other times of the year. The dominant intertidal plant, the brown alga Hormosira banksii, was affected by trampling, but the effects were heterogeneous between sites. At two sites, a series of pulse disturbances produced a series of pulse responses, although the effect of a given pulse varied among years, possibly related to the severity of summer desiccating conditions each year. At the third site, pulse disturbances produced a press response; at high levels of trampling, Hormosira was almost eliminated within 2 yr, and at two intermediate levels of trampling, cover was reduced from >90 to 60-70%, where it remained for 4 yr. Effects of trampling showed little small-scale spatial variation. Untrampled areas did fluctuate through time, often as a result of summer burnoff of algae. Natural disturbances occurred irregularly through the study, and their effects varied on very small spatial scales (among plots <30 m apart). Trampling enhanced the densities of a range of herbivorous mollusks, especially limpets, and reduced the abundance of articulated coralline algae, which were abundant in the understory of Hormosira mats. These effects varied among sites but showed much less variation on smaller spatial scales. The reductions in coralline algae may be a direct effect of trampling, but increases in mollusk abundance occurred some time after changes to Hormosira cover, and those changes may be an indirect effect of trampling. We compared the effects of trampling on areas of the shore that had been trampled for two and four summers, to test whether a past history of disturbance influenced the effect of a new disturbance. No significant effects were found on algae or mobile animals, although a mild summer may have made our test of history relatively weak. Hormosira banksii fits the definition of a keystone species or engineer and, as such, is an appropriate focus for management and as an indicator. Spatially heterogeneous effects of a constant physical perturbation, however, mean that management of these rocky shores requires more complex models and indicate that caution should be used in adopting this species as a uniform indicator of environmental change.

Populations of mountain golden heather (Hudsonia montana), a threatened North Carolina shrub, are declining due to the suppression of natural fires and increased trampling by hikers and campers. Consequently, proposed management strategies have focused on conducting controlled burns and restricting human traffic. To help design an optimal management plan, we used demographic data from a 5-year field study of H. montana--which included a controlled burn--to construct size-based population projection matrices. Using these matrices, we projected the consequences of instituting controlled burns and hiking and camping restrictions separately and in tandem. We also determined the burn frequency that would maximize H. montana's population growth rate. Finally, we used a stochastic model to determine how environmental fluctuations could alter the efficacy of conservation measures. Our results suggest that, although neither burning nor trampling reduction alone can reverse H. montana's decline, a judicious combination of the two has an excellent chance of doing so. A burn frequency of once every 6-8 years should maximize H. montana's population growth, although the interburn interval could be increased to 12-16 years without significantly jeopardizing the success of the management plan. Our results show that, even with the limited data available, size-based projection matrix models can be useful tools for identifying promising combinations of multiple management strategies for most threatened plants.

The aim of the study is to contribute to the knowledge of the path carrying capacity in the Belianske Tatry Mts and to propose the tourism regulation. We determined the criteria for the evaluation of the path carrying capacity and we created the limits and proposals for the using. This led to the criteria determination for general landscape use, which can be potentially used for the territory landscape ecological regionalization and optimization. We evaluated 3 tourist paths localized in the territory of the fifth (the strictest) degree of protection, which are in use during the tourist season (since 16th June till 31st October). Each path was divided into separately evaluated parts. There were: a) path from the Javorina village to the Kopské sedlo saddle (educational path), b) path from the Monkova dolina valley through the Široké sedlo saddle to the Kopské sedlo saddle (educational path) and c) path through the Dolina Siedmich prameňov valley (Slovak Republic).

Land managers often suggest fencing to protect rare plant species from being trampled in heavily used recreation areas, but there are few documented examples of the efficacy of this strategy. In a 7-year demographic study we examined the reproduction, survival, and long-term viability of the endangered sentry milk-vetch (Astragalus cremnophylax var. cremnophylax) before and after protection from trampling. Demographic monitoring and population viability analyses indicated that the population has fluctuated during the 7 years. Before protection the population declined: 26% of individuals died, mortality surpassed natality, and age of first reproduction was significantly older than post-protection. Fifty-eight percent of the population was severely damaged. Population viability analyses of pre-protection years predicted that the population would go extinct within 100 years. Since protection, the population stabilized, grew, and declined again. Seedlings reached reproductive maturity more quickly. Recruitment increased and peaked in 1993 coincident with abundant precipitation, but again declined in 1994. The total numbers of undamaged plants surpassed the numbers of damaged plants. Models of the post-protection population predict stability. Multiple-linear regression analysis indicated that winter and spring precipitation were significantly correlated with lambda. Both \"good\" and \"bad\" climatic conditions occurred during the pre- and post-protection periods. Because of small population size and depauperate genetic diversity, climate will continue to influence population growth. Nevertheless, models indicate that where trampling and bad climatic conditions were coupled, extinction was accelerated. Recovery of sentry milk-vetch will depend on continued protection, augmentation, and environmental factors, although risk of extinction remains very high.

We examined experimentally the effects of disturbances caused by pedestrian traffic on the animals and plants living on an intertidal rocky shore in south-eastern Australia. Individual footsteps damaged some animals, but the percentage of animals that was crushed was low. Molluscs, except large limpets, were more often dislodged than crushed, and some damage was sustained by barnacles and mussels. The survival of individuals of two gastropod species, Bembicium nanum and Austrocochlea constricta, was not affected by dislodgment, because they quickly righted themselves. The limpet Cellana tramoserica was not damaged by being kicked or stepped on. The dominant plant on these shores, the brown alga Hormosira banksii, was easily damaged, with ca. 20% of the biomass of individual plants being removed by a single footstep. The amount of tissue lost increased with the number of footsteps, with a maximum loss of approximately 75%. We investigated the effects of three levels of sustained trampling (33 d of trampling, spread over 4 mo) on the organisms in three habitats: Hormosira Mats, Coralline Algal Mats, and Bare Rock. The algal mats were most affected by trampling. Hormosira Mats were damaged severely by high- and low-intensity trampling. Upright coralline algae in the Coralline Algal Mat were damaged by high-intensity trampling. Numbers of the gastropod Turbo undulatus in both of these habitats were reduced. The Bare Rock habitat was not affected significantly by trampling. Five months after the end of trampling, heavily trampled and control strips of coralline Algal Mats were not distinguishable, as all treatments underwent pronounced seasonal changes. Within the Hormosira Mats, the low-intensity treatments and controls were not different, but algal cover in the heavily-trampled areas remained < 50% of pre-trampling levels. Within this habitat, the Hormosira had not recovered and there were substantial increases in the abundances of some grazing molluscs, particularly limpets. Even after > 400 d of recovery, Hormosira cover was only 60%, three quarters of the value for control areas. The indirect effect of increased mollusc abundance was still apparent. Trampling by visitors could result in replacement of the Hormosira mat species assemblage with 'bare' rock and grazing molluscs, and trampling should be considered as a disturbance capable of directly and indirectly influencing intertidal populations on rocky shores.

Plant communities of trampled soil dominated by plants characterized by the C4-assimilation syndrome were investigated in Europe. These species, belonging to genera such as Chamaesyce, Amaranthus, Eleusine, Eragrostis and Setaria, are thermophilous, late-germinating, prostrate herbs or grasses. The centre of their distribution is in the (Sub)Tropics. A syntaxonomic revision of the phytosociological material from Europe (incl. the Macaronesian Archipelago) revealed three alliances: the Euphorbion prostratae from Spain, the Polycarpo-Eleusinion indicae from Italy, and Slovenian and Croatian Istria, and the Eragrostio-Polygonion arenastri from temperate regions of Europe. The latter two syntaxa are described as new. All three alliances belong to the order Eragrostietalia (class Stellarietea mediae). Vicarious (ecologically analogous) communities occur also in southern Africa, eastern Asia and North America. The communities studied in the present paper are considered to be an impoverished form of highly diversified trampled plant communities typical of (sub)tropical areas.

Seedling emergence and establishment was monitored in 3 microhabitats during growing seasons in a Mediterranean coastal sand dune community in Poleg Stream Nature Reserve, Israel. Seedling emergence varied temporally among the 3 microhabitats, with a delay in the timing of seedling emergence in shrub understoreys due to lower soil average temperatures and lower irradiance. In contrast, seedling emergence on trails was advanced because of more intense irradiance and higher soil temperatures on their more exposed soil surfaces. Microhabitats showed significant differences in individual densities, species diversity, and species richness of total seedlings (P < 0.0001). Open areas generally possessed significantly greater total seedling densities, species diversity, and species richness compared to shrub understoreys and trails. Twelve key species and 5 functional groups showed significant microhabitat preferences. Seedling patterns indicated that emergence responses could account for observed patterns of variation in the 5 functional groups and dominant species populations. In this semi-arid ecosystem, negative interactions between the shrub canopy species (white weeping broom) and its understorey occurred for seedling establishment because of lower seed densities in the seed bank, a larger amount of litter on the soil surface, and the dense woody canopy. On the trails, trampling decreased plant diversity and discouraged the establishment of most functional groups and key species except annual grasses and Polycarpon succulentum and Cutandia philistaea. The variability in seedling response patterns for the different microhabitats will assist in understanding the patchy regeneration strategies of this coastal sand dune community and provide a basis for vegetation management. Nomenclature: Fragman et al., 1999.

Vertebrate herbivores can be effective agents of biological weed control in certain applications. I compared the use of domestic geese for weed control in an agricultural field with the herbicide hexazinone and with hand control. Newly planted spruce seedlings acted as a prototype crop that would be unpalatable to the geese. Trampling by geese led to as much as 47% tree seedling mortality during the 1st yr; this was reduced significantly by either limiting the amount of time the geese spent in the plots or surrounding seedlings with small wire fences. When compared with plots with no weed control, weed control by geese improved the diameter growth of the surviving seedlings by over 100% during the 1st yr of the study, but had no effect in the 2nd yr. The geese controlled a variety of weed species, but were most effective against quackgrass (Agropyron repens). However, grazing effectively selected for unpalatable weed species (including pineapple weed, Matricaria matricarioides, prostrate knotweed, Polygonum aviculare, and wild chamomile, Tripleurospermum phaeocephalum) so that by the end of the 2nd yr plots weeded only by geese had 25 times as much cover of unpalatable species as plots with no weed control. In contrast, the herbicide was ineffective against grass and effective against the unpalatable weed species. A successful integrated weed management strategy would thus require combining geese with another method of weed control, and would include measures to prevent crop trampling.