Risto Kalliola

Dissecting amazonian biodiversity.

Biogeographical and biodiversity studies in Iowland Amazonian rain forests typically refer to observed or postulated distribution barriers such as past unfavorable climates, mountains, rivers, and river floodplains that divide the uniform tierra firme (noninundated) forest. Present-day ecological heterogeneity within tierra firme has hardly been discussed in this context, although edaphic differences are known to affect species distribution patterns in both inundated areas and tierra firme. Quantification of landscape heterogeneity in Peruvian Iowland Amazonia (500,000 kilometers squared), based on field studies and satellite image analysis, shows that Peruvian Amazonia is considerably more heterogeneous than previously reported. These observations have implications for the research, management, and conservation of Amazonian biodiversity.

Fluvial Perturbance in the Western Amazon Basin: Regulation by Long-Term Sub-Andean Tectonics

Haffers refuge theory proposes that during the arid climatic phases of the late Pleistocene, tropical lowland forests of Amazonia were reduced to isolated patches contributing to the high species richness of the present-day forest. The theory was developed because no obvious historic or modern geomorphic isolation barriers were recorded in Amazonia. Analyses of radar images combined with stratigraphical data show that in the basinal forelands of the tectonically active Andes the geological setting causes long-term fluvial perturbance. This leads to a temporally structured highly complex mosaic of fossil and present floodplains. These dynamics have been present with varying activity and geographic range during the Tertiary and Quaternary, providing site-turnover that has not been recognized by the biogeographic tradition of the Amazon basin.

New site formation and colonizing vegetation in primary succession on the western Amazon floodplains.

The major proportion of western Amazon forests grow on fluvial deposits and thus originated in floodplain environments. The fluviodynamic character of the sites initially colonized by plants was studied along different river types, and this information was combined with botanical observations from the same areas. Special emphasis was given to colonizing plant distribution and survival in relation to the abiotic environment. Four frequently occurring landform types, each rich in microforms, were recognized in relation to the colonization process : fluvial bars, swales, abandoned channels and riverbanks (...)

Structure of a pristine Picea abies forest in northeastern Europe

. The forest structure in a large, relatively homogeneous area of pristine Picea abies taiga in the southern boreal region west of the Ural mountains was studied along four 500-m long transects. P. abies dominated the forest in association with Abies sibirica and Betula spp. The mean volume of living trees was 216 m3/ha. This value varied among the four transects, from 138 - 252 m3/ha. Mean density of trees (DBH > 1 cm) (and variation over the transects) was 2 064/ha (1670 - 2710). Living trees classified as dying or seriously damaged made up 2.9 (2.5 - 3.5) % of the living tree volume. Betula was an important canopy component and made up 16% of the living tree volume. The number of dead standing trees varied from 195 - 325/ha, corresponding to a volume of 10.8 - 70.7 m3/ha. The density of trees with a broken stem was 90 - 170/ha and their estimated volume 7.6 - 41.3 m3/ha. Standing dead trees and trees with broken stems represented 10.4 and 8.9% of the total standing tree volume (living + dead), respectively. The mean volume of decaying logs on the forest floor was 117 (84.4–156.2) m3/ha, corresponding to 54 (35 - 113) % of the living tree volume. The canopy-forming trees were present in the understory as abundant saplings and suppressed individuals. The size distribution of the dominant tree species resembled the inverse J-shape. Generally, the forest was characterized by a high small-scale structural variation and a larger-scale relative homogeneity. This pattern is consistent with forest dynamics where the forest consists of a small-scale mosaic of patches in different stages of recovery following disturbance. Our results suggest that the ecology and dynamics of extensive areas of natural boreal forests can be driven by small-scale disturbance.

River dynamics and vegetation mosaicism: a case study of the River Kamajohka, northernmost Finland

Vegetation was classified and mapped along the small meandering River Kamajohka in peatlands in northernmost Finland. The results show a mosaic of thirteen communities, mainly woody grasslands and mire types. They may be schematically arranged into a developmental order that represents the flood-controlled successions on well-drained and poorly-drained areas. Channel migration largely determines the bound- aries between vegetation groups, and river migration is a natural perturba- tive factor that causes continuous site turnover. All of the current floodplain vegetation has originated from riparian primary successions, and all riparian vegetation may be destroyed by further river erosion. Some vascular plants benefit from special habitats created by river channel migration, though flood influences (duration and magnitude) are probably the most important factors affecting species distribution. Six recent chan- nel abandonments illustrate the heterogenous nature of sedimentary pat- terns and vegetation successions; they are important components of the vegetation mosaic along the river.

River types, site evolution and successional vegetation patterns in Peruvian Amazonia

Lateral migration of Amazonian lowland rivers causes a vegetation succession on recently deposited fluvial sediments. The forest ground is formed gradually in se- quence, giving rise to age-zonation of the successional stages. Using Landsat MSS maps and field observations, we studied variations in fluvial landform evolution and river character. The widely used characterizations of the rivers ac- cording to their suspension-load character and channel pattern were evaluated in relation to the vegetation succes- sion. Sequential successional forests appear extensively along meandering white-water rivers, which are rich in sus- pended sediments and are characterized by mobile channels. Conversely, vegetation zonation is less pronounced at the margins of slowly eroding suspension-poor rivers. Line transects were established to document meander develop- ment along eight different rivers. The chemical composition of the recently deposited alluvium differs markedly both among rivers and along the transects. Concentrations of organic carbon and nitrogen increase toward the meander neck along with the acid reaction of the soil. The rate of riv- erine forest regeneration in Peruvian lowland Amazonia was extrapolated on the basis of erosion data from four different rivers, and suggests that approximately 130 km2 of forest is annually eroded and replaced by successional vegetation, the equivalent of 0.2% of the present floodplain area of this region.

Road construction in the Peruvian amazon : process, causes and consequences

In the north-western Peruvian Amazon, a new road has recently been constructed to link the city of Iquitos with the town of Nauta. The road crosses lands that are remarkably heterogeneous in terms of ecological conditions, comprising distinctive soil types from extremely poor to relatively fertile. Although this reality contributes to the land use potential and human carrying capacity of each place, deforestation of road margins appears equally intensive on all types of land. In the mid-1990s, two dead-end roads starting from both urban centres were characterized by distinctive zones of resource exploitation, with a road-free section of primary forest in between. A few years later, the separate road ends were linked by a dirt road that served only occasional traffic, but introduced significant new settlement. Various developmental trends evidence incoherent resource management and momentary public support in the region. By promoting diverse economic activities that reflect environmental conditions in the initial land use planning and land allocation, most sections along this road could be considered economically valuable for purposes such as sustainable forestry, tourism, agroforestry and, in suitable sites, intensive agriculture. To promote the more sustainable uses, thorough environmental legislation, administrative guidelines and follow-up based on an implicit mechanism of learning from previous experiences should be implemented. At the local level, there are some important initiatives to support such development, including ecological and economic zoning. However, these measures might be too late to prevent the destructive practices so common in many parts of Amazonia.

Systematic Assessment of Maps as Source Information in Landscape-change Research

A methodology is proposed for systematic map assessment to contribute to landscape-change research. Two major topic areas are dealt with, namely: content, quality and usefulness of landscape information on different maps; and methods used in the spatial conversion of maps into digital systems (e.g. geographical information systems). The major focus is on information about physical landscape characteristics (e.g. land cover) and land uses. The approach was tested using a sequence of nine large- and medium-scale basic maps of the island of Ruissalo in SW Finland from between 1690 and 1998. Fundamental differences were found in the thematic consistency of landscape information, mainly related to the scale, purpose and generalization of landscape information on different maps. Spatial matching was tested for a set of three old maps using four image rectification functions. The results showed that spatial matching of old maps is difficult, and success in rectification is influenced by many factors. Evaluation and selective transformation of landscape information from maps and the use of supportive information from other sources can assist in landscape-change analysis based on map sequences.

Monitoring Current Status of and Trends in Boreal Forest Land Use in Russian Karelia

Some of the last remaining near-natural boreal forest landscapes in northern Europe can be found in the Russian Karelia near its border with Finland. Currently, these forests are facing strong exploitation pressure in the form of extensive clearcuts. Demand for conservation is also high. We characterize the boreal forest landscape in the region and assess the impacts of past and potential management actions through a mapping and modeling study that synthesizes methods from landscape ecology, remote sensing, and simulation modeling. The forests of the study area were mapped using techniques for interpreting multitemporal satellite images and detecting changes. The species composition and structure of the forests were estimated using the multisource k-nearest neighbors (k-nn) method. Forest harvesting rates and current landscape patterns were used to parameterize models built with a cell-based Spatially Explicit Landscape Event Simulator (SELES) modeling tool, and alternative land- use policy strategies were simulated with and without natural fire. Based on 10 Monte Carlo runs for each scenario, we can predict dramatic changes in the forest landscape structure after 30-70 yr. The current, complexly structured, near-natural forest assemblage will rapidly be converted into its transpose: an expanse of young regeneration stands, with blocks of near-natural forest extant only as islands within mires and in the reserve areas. The prompt establishment of the proposed Kalevala National Park is regionally important for these reasons: (1) to increase the types of near-natural forest conserved, (2) to provide a second large biodiversity source adjacent to the heavily fragmented Finnish forests, and (3) to reduce the currently inflated rate of harvesting.

Mineral nutrients in fluvial sediments from the Peruvian Amazon

Abstract Mineral nutrient content was determined from fluvial sediments of eight different rivers in Peruvian Amazonia. Statistically significant differences between the floodplains were detected in the mean values of soil reaction, conductivity, concentrations of total phosphorus, calcium and aluminium, concentrations of extractable sodium, calcium and aluminium, and in the ratios Ca/Mg and Mg/K. Principal components ordination based on geochemical variables exhibits a spectrum from rivers depositing sediments rich in extractable bases, to those which deposit sediments acid in reaction and rich in extractable aluminium. The distribution of the sediment types corresponds to the geology of the catchment area. Fluvial sediments of suspension-rich rivers of Andean origin are rich in their extractable mineral nutrient content; especially calcium is prominent. Differences in the chemical properties of fluvial sediments contribute to the regional heterogeneity of the environment in the lowland Peruvian Amazon and are likely to affect the distribution of plant species. Since the origin of most of the soils in this region is fluvial, sediment provenance and age should be considered in soil surveys.