Proportion Of Woodland Research Articles

Influence of habitat on home-range size in the short-beaked echidna

The size of an animal’s home range is strongly influenced by the resources available within it. In productive, resource-rich habitats sufficient resources are obtainable within a smaller area, and for many species, home ranges are smaller in resource-rich habitats than in habitats with lower resource abundance. Location data on 14 male and 27 female echidnas (Tachyglossus aculeatus) fitted with tracking transmitters, in the southern midlands of Tasmania, were used to test the influence of habitat type on home-range size. We hypothesised that as woodland should offer more shelter, food resources and refuges than pasture, echidnas living in woodland would have smaller home ranges than those living in pasture areas. We found significant differences between the sexes. Male echidnas had a significantly larger mean home range than females and a quite different relationship between home-range size and habitat type from females. There was no relationship between the proportion of woodland within male home ranges and home-range size whereas female echidnas had a highly significant negative relationship. This suggests that home-range size of female echidnas is highly influenced by the amount of woodland within it, but the home-range size of male echidnas is controlled by factors other than habitat. This pattern is consistent with the spatial ecology of many other solitary species with a promiscuous mating system. The home ranges of females are scaled to encompass all necessary resources for successfully raising their young within a minimal area, whilst the large home ranges of males are scaled to maximise access to females.

Effect of crop management and landscape context on insect pest populations and crop damage

Understanding the determinants of insect–plant interactions and pest population dynamics at multiple spatial scales is a pre-requisite for developing innovative crop protection strategies and increasing the sustainability of agroecosystems. In a two-year study, we investigated the relative influence of local crop management and landscape context on pollen beetle (Meligethes spp.) abundance and damage at 8 different spatial scales around 42 oilseed rape fields using a multi-model inference approach. We found that pest abundance was mainly determined by the proportion of grassland and woodland in the landscape at scales ranging from 1500m to 2000m. Pollen beetle damage was affected both by local management and landscape predictors at scales ranging from 1500m to 2000m. Indeed, damage was negatively correlated with the nitrogen nutrition index of the plants and positively correlated with the proportion of woodland in the landscape at a large scale. Our multi-scale approach revealed that landscape complexity determines pollen beetle abundance in the spring and that nitrogen nutrition of the plants influences crop ability to compensate bud abortions resulting from pest attacks. The results are discussed in relation to crop management, pest dispersal ability and landscape structure.

Predicting the rate of range expansion of an invasive alien bumblebee ( Bombus terrestris) using a stochastic spatio-temporal model

To develop effective strategies for managing biological invasions, it is important to understand and be able to predict patterns of invasion and range expansion, and particularly the rate of spread and factors controlling this rate. To predict the spatial dynamics of invasion by an alien bumblebee ( Bombus terrestris) in Hokkaido, Japan, we explicitly constructed a stochastic spatio-temporal model that incorporates immigration and establishment processes. Using a Bayesian approach, we parameterized the model based on spatio-temporal presence/absence data collected by citizen volunteers and used the model to predict control of the near-future spread of the bumblebee under several management strategies. The range expansion dynamics of B. terrestris were significantly negatively affected by two aspects of environmental heterogeneity: the land-use pattern (the proportion of woodland) and climate (the snow depth). Of the several spatial management strategies, suppressing the outlying (edge) colonies would be the most efficient strategy to reduce the bumblebee’s spread, irrespective of the level of effort, and would significantly slow the bumblebee’s range expansion during the next 30 years. The modeling approach employed in the present study will be broadly useful for studying real-world biological invasion problems, for which prediction of the progress of an invasion, even in the very near future, is urgently needed to support effective spatial management options and countermeasures. In addition, the model demonstrates that incorporating the dynamics of environmental heterogeneity is a fundamental requirement for prediction and risk assessment during biological invasions, especially in the context of recent rapid changes in the environment at regional and global scales.

Spatial structure of avifauna along urban‐rural gradients

AbstractWe examined the pattern of species composition of breeding birds along urban‐rural gradients in the Osaka Prefecture, western Japan. We recorded the proportion of nine types of land‐use and the presence/absence of each of 76 breeding birds in 5 km square quadrats on a map of the Prefecture. The proportion of woodland and farmland which increased from urban to rural areas were two major enviornmental gradients according to Principal Component Analysis of the nine types of land‐use. Ordination by Canonical Correspondence Analysis (CCA) showed that the breeding bird distribution differentiated along the two major clines, woodland and farmland. The avifauna changed successively along these environmental gradients. There were no discrete boundaries of the distribution of bird species groups. We tentatively classified five groups of quadrats on the ordination plane of the sample score. The geographic position of these five groups on a map preserved the environmental gradient, but showed that water (seashore and river) was a stronger influence on bird species composition than land‐use pattern. Although the diversity of land‐use seemed to raise species richness in the third group, the less diverse, woodland‐rich group contained as many species as the third group. Four groups of bird species, and one group in which species occurred in more than 90% of the quadrats, were classified in the CCA‐ordination plane. The occurrence of these bird groups correlated with land‐use; the first group with woodland area, the second with scatter woodland, the third with farmland and the fourth with seashore.

The Airfall-pollen Budget of Archaeologically Important Caves: Creswell Crags, England

This paper investigates fundamental taphonomic issues for palynologists working on archaeologically important cave deposits—the extent to which the pollen and spores reaching the accumulating sediment surfaces reflect the vegetation in cave entrances, or reflect the more regional environments beyond the caves. The study sites were four adjacent caves at Creswell Crags, near Sheffield, England—Church Hole, Dog Hole, C7 and Robin Hood's Cave. The compositions of the pollen and spore assemblages caught in the caves over a one year period were shown to reflect the vegetation in the cave mouths and the wider area beyond. The AP:NAP ratio in the assemblages trapped in the caves corresponded with the proportions of woodland and open ground within a 5 km radius of the site. Comparatively high representations of fern spores in caves were a persistent feature and were attributed to the interactions of habitat, distribution and taphonomic processes—(i) the abundance of ferns in cave mouths, and (ii) the effects produced by a combination of diurnal micro-climatological process interacting with diurnal variations in spore production in the cave entrance. In two caves—Church Hole Cave and Dog Hole Cave—the numbers of grains caught appeared to decline with increasing distance into the cave. In Cave C7, the numbers of grains caught increased towards the back of the cave. The number of grains caught appears to be a principal determinant of the number of plant taxa identified. There were no clear relationships between the presence of a "flue" effect in the cave and the presence of an increase or a decrease in the number of grains caught with changing distance into the caves. It is concluded that as long as account is taken of the particular topographic, microclimatic and taphonomic conditions in these caves, it is possible to infer the character of the vegetation beyond their confines, from the airfall pollen and spores trapped with them at the cave sediment surface.

WOODLAND CLEARANCE IN ENGLAND AND WALES—A CASE STUDY OF POST-WAR CHANGE IN NOTTINGHAMSHIRE

Summary Compared to other Western European states Britain has only a small proportion of woodland. Although in net terms the woodland area has been increasing during the twentieth century, when the gross figures are assessed a considerable amount of woodland clearance is indicated. This paper considers the results of a survey of woodland ownerships in Nottinghamshire and in a series of case studies the reasons for woodland clearance and the effectiveness of public controls designed to restrict clearance are discussed.