Matti Koivula

Boreal carabid-beetle (Coleoptera, Carabidae) assemblages along the clear-cut originated succession gradient

We examined the occurrence of carabid beetles along a forest successiongradient in central Finland (forest age classes: 5, 10, 20, 30 and 60years since clear-cutting). Species richness of carabids was higherin the two youngest age classes, while no clear differences were detected incarabid abundance. The high species richness in the young, open sites was due toinvasion of open-habitat species. Many forest species were absent from or scarcein the young sites and became gradually more abundant towards the older forestage classes. The catches indicated a drastic decrease and assemblage-levelchange in concert with canopy closure, i.e. 20–30 years afterclear-cutting. Some forest specialists with poor dispersal ability may facelocal extinction, if the proportion of mature forest decreases further and theremaining mature stands become more isolated. We recommend that, whileharvesting timber, connectivity between mature stands is ensured, mature standsare maintained close (a few tens of metres) to each other and the matrix qualityis improved for forest species by green tree retention.

Alternative harvesting methods and boreal carabid beetles (Coleoptera, Carabidae)

Abstract I studied carabid-beetle assemblages in boreal spruce-forest stands representing early secondary succession, produced by three different logging methods, in central Finland in 1995–1998. The logging methods studied in eight separate study areas were: unlogged control stands, traditionally clear-cut stands, stands within which three 1600xa0m 2 openings were felled and stands of modified clear-cutting, within which three small tree groups (20–30 live standing mature trees) were retained. Pre-treatment samples were collected in 1995 and the stands were logged the following winter. A three-summer follow-up study indicated the following. (1) Carabid assemblages changed with varying speed and intensity after logging. (2) Stands with small openings maintained the original assemblage structure best. Generalists were more abundant in clear-cut stands than in the stands with openings, indicating stronger assemblage-level changes in the large clear-cuts. (3) Carabid species showed varying responses to a moisture gradient, to the amount of trees removed and to the abundance of red wood ants. Some forest species with poor dispersal ability were associated with for closed and moist or mesic sites. These findings are discussed in the light of the ecological characteristics of the species and in relation to forest management.

Evaluation of carabid beetles as indicators of forest change in Canada 1

Our objective was to assess the potential of carabid beetles (Coleoptera: Carabidae) as effective bioindicators of the effects of forest management at a Canadian national scale. We present a comparison of carabid beetle assemblages reported from large-scale studies across Canada. Based on the initial response following disturbance treatment, we found that carabid assemblages consistently responded to disturbance, but responses of individual species and changes in species composition were nested within the context of regional geography and finer scale differences among forest ecosystems. We also explored the relationship between rare and dominant taxa and species characteristics as they relate to dispersal capacity and use of within-stand habitat features such as coarse woody debris. We found no relationship between life-history characteristics (such as body size, wing morphology, or reported associations with downed wood) and the relative abundance or frequency of occurrence of species. Our results suggest that carabids are better suited to finer scale evaluations of the effects of forest management than to regional or national monitoring programs. We also discuss several knowledge gaps that currently limit the full potential of using carabids as bioindicators.

Breeding bird species diversity across gradients of land use from forest to agriculture in Europe

Loss, fragmentation and decreasing quality of habitats have been proposed as major threats to biodiversity world-wide, but relatively little is known about biodiversity responses to multiple pressures, particularly at very large spatial scales. We evaluated the relative contributions of four landscape variables (habitat cover, diversity, fragmentation and productivity) in determining different components of avian diversity across Europe. We sampled breeding birds in multiple 1-km2 landscapes, from high forest cover to intensive agricultural land, in eight countries during 2001−02. We predicted that the total diversity would peak at intermediate levels of forest cover and fragmentation, and respond positively to increasing habitat diversity and productivity; forest and open-habitat specialists would show threshold conditions along gradients of forest cover and fragmentation, and respond positively to increasing habitat diversity and productivity; resident species would be more strongly impacted by forest cover and fragmentation than migratory species; and generalists and urban species would show weak responses. Measures of total diversity did not peak at intermediate levels of forest cover or fragmentation. Rarefaction-standardized species richness decreased marginally and linearly with increasing forest cover and increased non-linearly with productivity, whereas all measures increased linearly with increasing fragmentation and landscape diversity. Forest and openhabitat specialists responded approximately linearly to forest cover and also weakly to habitat diversity, fragmentation and productivity. Generalists and urban species responded weakly to the landscape variables, but some groups responded non-linearly to productivity and marginally to habitat diversity. Resident species were not consistently more sensitive than migratory species to any of the landscape variables. These findings are relevant to landscapes with relatively long histories of human land-use, and they highlight that habitat loss, fragmentation and habitat-type diversity must all be considered in land-use planning and landscape modeling of avian communities.

Bioassess bird data

Landscape variables and avian point-count species richness data collected in the BioAssess project 2001-2002 in eight European countries