Forest Interior Areas Research Articles

Profound impoverishment of the large-tree stand in a hyper-fragmented landscape of the Atlantic forest

Large tree species have a disproportional influence on the structure and functioning of tropical forests, but the forces affecting their long-term persistence in human-dominated landscapes remain poorly understood. Here we test the hypothesis that aging forest edges and small fragments (3.4–295.7 ha) are greatly impoverished in terms of species richness and abundance of large trees in comparison to core areas of forest interior. The study was conducted in a hyper-fragmented landscape of the Atlantic forest, northeast Brazil. Large tree species were quantified by recording all trees (DBH ≥ 10 cm) within fifty-eight 0.1-ha plots distributed in three forest habitats: small forest fragments ( n = 28), forest edges ( n = 10), and primary forest interior areas within an exceptional large forest remnant ( n = 20). Large tree species and their stems ≥10 cm DBH were reduced by half in forest edges and fragments. Moreover, these edge-affected habitats almost lacked large-stemmed trees altogether (0.24 ± 0.27% of all stems sampled), and very tall trees were completely absent from forest edges. In contrast, large trees contributed to over 1.5% of the whole stand in forest interior plots (2.9 ± 2.8%). Habitats also differed in terms of tree architecture: relative to their DBH trees were on average 30% shorter in small fragments and forest edges. Finally, an indicator species analysis yielded an ecological group of 12 large tree species that were significantly associated with forest interior plots, but were completely missing from edge-affected habitats. Our results suggest a persistent and substantial impoverishment of the large-tree stand, including the structural collapse of forest emergent layer, in aging, hyper-fragmented landscapes.

Spatially explicit models to analyze forest loss and fragmentation between 1976 and 2020 in southern Chile

Forest fragmentation threatens biodiversity in one of the last remaining temperate rainforests that occur in South America. We study the current and future impacts of fragmentation on spatial configuration of forest habitats at the landscape level time in southern Chile. For this purpose, we identify the geophysical variables (“pattern drivers”) that explain the spatial patterns of forest loss and fragmentation between 1976 and 1999 using both a GIS-based land-use change model (GEOMOD) and spatially explicit logistic regression. Then, we project where and how much forest fragmentation will occur in the future by extrapolation of the current rate of deforestation to 2010 and 2020. Both modeling approaches showed consistent and complementary results in terms of the pattern drivers that were most related to deforestation. Between 1976 and 1999, forest fragmentation has occurred mainly from the edges of small fragments situated on gentle slopes (less than 10°) and far away from rivers. We predict that patch density will decline from 2010 to 2020, and that total forest interior area and patch proximity will further decline as a result of forest fragmentation. Drivers identified by these approaches suggest that deforestation is associated with observed local socio-economic activities such as clearance of forest for pasture and crops and forest logging for fuelwood.

An Assessment of Poverty and Living Standard of the Baigas of Samnapur Block of Dindori District, Madhya Pradesh

The present paper elucidates some aspects of poverty and living standard of Baigas of Samnapur block of Dindori district Madhya Pradesh. Baiga is one of the most primitive tribal groups of central India. Out of total Baiga villages of Samnapur block Simardha and Tikariya village were randomly selected for the purpose of study and out of these two villages a total of 100 households comprising of 494 individuals were randomly selected and interviewed. The information was gathered through interview using a pretested structured schedule. The findings reveal that a majority of the population is poor and illiterate. As most of them live in the interior forest areas away from the main stream their living standard also reflects the same. Many of them are not even able to consume the fruits of recent development occurring elsewhere in the world. Agriculture is one of the major sources of income among them but they are required to be trained about new techniques and methods of it which can bring a substantial increase in their yield. Thus there is an urgent need to launch some income generating programmes to improve their economic status by different government and non government organizations. (authors)

Drastic erosion in functional attributes of tree assemblages in Atlantic forest fragments of northeastern Brazil

The long-term dynamics of plant communities remain poorly understood in isolated tropical forest fragments. Here we test the hypothesis that tropical tree assemblages in both small forest fragments and along forest edges of very large fragments are functionally much more similar to stands of secondary growth (5–65-yr old) than to core primary forest patches. The study was carried out in a severely fragmented landscape of the Brazilian Atlantic forest. Nine functional attributes of tree assemblages were quantified by sampling all trees (DBH ⩾ 10 cm) within 75 plots of 0.1 ha distributed in four forest habitats: small forest fragments (3.4–79.6 ha), forest edges, second-growth patches, and primary forest interior areas within a large forest fragment (3500 ha). These habitats were markedly different in terms of tree species richness, and in the proportion of pioneer, large-seeded, and emergent species. Age of second-growth stands explained between 31.4% and 88.2% of the variation in the functional attributes of tree assemblages in this habitat. As expected, most traits associated with forest edges and small forest fragments fell within the range shown by early (<25-yr old) and intermediate-aged secondary forest stands (25–45-yr old). In contrast to habitat type, tree assemblage attributes were not affected by vegetation type, soil type and the spatial location of plots. An ordination analysis documented a striking floristic drift in edge-affected habitats. Our results suggest that conservation policy guidelines will fail to protect aging, hyper-fragmented landscapes from drastic impoverishment if the remaining forest patches are heavily dominated by edge habitat.

Influence of litter removal and mineral soil disturbance on the spread of an invasive grass in a Central Hardwood forest

Soil and litter disturbances within Central Hardwood forests may facilitate exotic plant species invasion of interior forest areas. Microstegium vimineum is an annual exotic grass that has become common throughout the Southeastern United States. Three replicates of three different mineral soil and litter disturbance treatments, plus a control with no disturbance, were established on the leading edge of M. vimineum patches prior to seed fall. All patches were located in areas with similar forest canopy structure and slope in three Central Hardwood forest stands prior to seed fall. At the beginning of the following growing season, each individual M. vimineum seedling was mapped within the treatment plots. The mean number of M. vimineum individuals that established within each treatment did not differ significantly from the control. The distance at which 90% of the individuals had spread, and the overall mean distance spread were significantly farther for the litter removal treatment than the control. The farthest individual seedling from the boundary of existing patches in both the litter removal and the mineral soil disturbance and litter removal treatments were significantly farther than the control. The individuals that spread the farthest are of most concern due to the large number of viable seed that a single M. vimineum plant can produce. These results suggest that disturbance of the litter layer may increase the spread rate of M. vimineum and facilitate its invasion of new habitats, and that leaving litter layers intact may slow the spread of M. vimineum.

Impacts of forest fragmentation on species composition and forest structure in the temperate landscape of southern Chile

ABSTRACTAim Few studies have explicitly examined the influence of spatial attributes of forest fragments when examining the impacts of fragmentation on woody species. The aim of this study was to assess the diverse impacts of fragmentation on forest habitats by integrating landscape‐level and species‐level approaches.Location The investigation was undertaken in temperate rain forests located in southern Chile. This ecosystem is characterized by high endemism and by intensive recent changes in land use.Method Measures of diversity, richness, species composition, forest structure and anthropogenic disturbances were related to spatial attributes of the landscape (size, shape, connectivity, isolation and interior forest area) of forest fragments using generalized linear models. A total of 63 sampling plots distributed in 51 forest fragments with different spatial attributes were sampled.Results Patch size was the most important attribute influencing different measures of species composition, stand structure and anthropogenic disturbances. The abundance of tree and shrub species associated with interior and edge habitats was significantly related to variation in patch size. Basal area, a measure of forest structure, significantly declined with decreasing patch size, suggesting that fragmentation is affecting successional processes in the remaining forests. Small patches also displayed a greater number of stumps, animal trails and cow pats, and lower values of canopy cover as a result of selective logging and livestock grazing in relatively accessible fragments. However, tree richness and β‐diversity of tree species were not significantly related to fragmentation.Main conclusions This study demonstrates that progressive fragmentation by logging and clearance is associated with dramatic changes in the structure and composition of the temperate forests in southern Chile. If this fragmentation process continues, the ability of the remnant forests to maintain their original biodiversity and ecological processes will be significantly reduced.

Changes in forest landscape structure in southern Finland in the late 1900’s

Finnish forest landscapes have experienced major changes during recent decades, and currently they are often regarded as fragmented. The assessment of historical landscapes and the quantitative documentation of supposed changes are matters that have largely remained unexplored, even though a thorough understanding of the historical processes and the existing pattern would be urgently needed for scientifically-based and sound management as the history and current landscape patterns may place long-term constraints on both ecological and economic objectives of future management options. The aim of this research was to define and quantify the changes in forest landscape structure caused by logging and road construction in private and state forests in southern Finland from the 1950’s to the 1990’s. Areas varying between 14 000 and 20 000 ha in different parts of southern Finland were selected for study. Both private and state-owned forest were included, but the proportion varied somewhat between locations. The forest cover was analysed using aerial photographs from successive decades, the forests in each area being classified into nocanopy and closed-canopy forest types. A more detailed analysis and classification employing several development stages was performed in one of the areas. The results show that the continuous cover of mature forests in the 1950’s has been broken up by extensive logging, and that major changes in the landscape structure had already taken place before the 1970. The continuous closed-canopy forest still forms the matrix, however, and its connectivity has slightly improved since the 1970’s, and mean size of no-canopy patches has slightly decreased. The interior forest areas are currently small, and edge-influenced forests make up a large portion of the landscape. Roads have had a greater impact on forest fragmentation than has harvesting, and increased harvesting can be attributed to road construction to some extent. Ecological allocation of harvests, the use of alternative harvesting methods, and local restoration of the important structures of natural forests are needed in order to reverse the effects of past management, but even so the current pattern of Finnish forests may be retained as a legacy for decades in the Finnish forests. Forest management and the planning of forest operations should be carried out at the landscape level in order to enhance the maintenance of historical patterns of landscape cover.

Species-area relationships and the impact of deer-browse in the complex phytogeography of the Haida Gwaii archipelago (Queen Charlotte Islands), British Columbia

:We studied the biogeography of vascular plants on 10 islands in Laskeek Bay, Haida Gwaii (Queen Charlotte Islands), British Columbia. The islands varied in size from 4.5 to 395 ha and experienced a range of different browse pressures from introduced black-tailed deer (Odocoileus hemionus). We examined how island size interacted with browse pressure in determining the total species counts for individual islands. Numbers of plant species recorded increased with island area. The regression exponent for the log–log plot of species number on island area was 0.18, at the lower end of the range for such exponents. Many species absent from islands < 25 ha in area were characteristic of forest interiors, and consequently part of the increase in richness on larger islands probably was the result of increased forest interior area. Among the islands < 25 ha in area, the normal species–area and species–isolation relationships were reversed, with smaller, more isolated islands supporting more plant species than larger islands and, for a given area, more isolated islands supporting more species than less isolated ones. This reversal of the normal trend appears to be the result of deer browsing. Small, isolated islands were the only islands without deer and were richer, especially in wildflowers, than the larger, less isolated islands. On large islands, total species complement remained as predicted by area because the effect of deer was mitigated by the presence of deer-free refugia on cliffs and in isolated gullies. We conclude that deer are a major factor structuring the island plant communities and that continued protection of island habitats from introduced deer is essential to maintain the native flora of Haida Gwaii.

Influence of forest road on breeding of tits in artificial nest boxes

A study was conducted to determine the influence of forest road on breeding of tits in artificial nest boxes in deciduous, coniferous and mixed forests in the Gwanak Arboretum (37° 25′ 05′' N, 126° 56′ 85″ E) of Seoul National University, Anyang, Korea from November 2002 to June 2003. Three tits species, varied tit (Parus varius), marsh tit (P. palustris) and great tit (P. major), breeding in artificial nest boxes were investigated on number of breeding pairs, cultch size, and egg measurement. Resuls showed that the breeding pairs of varied tit was more in 75–150 m area than in 0–75m area from forest road for all the three study sites, and the clutch size and egg measurements (weight, Major axis and Minor axis) of varied tit was also higher in the area of 75–150 m than in the area of 0–75 m, while no differences in number of breeding pairs and clutch size were found for, marsh tit and great tit between the two areas. Egg measurement of great tit was also higher in forest interior area than in forest edge area. It is concluded that varied tit were most significantly influenced by forest road, followed by great tit, whereas marsh tit were not influenced by forest road. Artificial nest box is roved to be good for cavity nester in disturbed areas by human activities. Supply of artificial nest can help population protection and management of bird species.

Spatial structure of disturbed landscapes in Slovenia

On the basis of land use maps, remote sensing techniques and GIS a spatial model was established to determine landscape types in Slovenia, specifically core areas of the primary forest and spatial structure of agricultural areas with intensive agricultural production. Forest and forested landscapes in Slovenia encompass 72% of the country's surface area. Using the spatial model, open space without forest patches, hedgerows and remnants of natural vegetation was observed in 44% of the area designated as farmland with intensive agricultural production. Pomurje is the sole Slovenian macroregion in which agricultural landscape still prevails. Most forest patches and forest fragments in the central part of the Pomurje macroregion are isolated and have a minor depth of interior forest area. They represent the ecological infrastructure for sustainable management of the cultural landscape. Despite the low level of forest cover in the macroregion (27%), just 52% of the area of agricultural and urban land is located more than 150 m from forest edges, hedgerows, and remnants of the former natural vegetation. Human corridors, urban centers, and smaller, scattered settlements also affect the stability and processes sustained by these landscape elements. It is in such cases that this spatial model may prove to be an efficient tool for spatial planning and for assisting in the coordination of different land users.

Effects of forest policy on landscape pattern of late-seral forest of the Western Olympic Peninsula, Washington

Forest harvest policies and regulations in the Pacific Northwest region of the United States have changed considerably across all land ownerships over the last 25 years, primarily in response to concerns over threatened and endangered species. For example, in July 2001, Washington State adopted new forest practice rules for private ownerships, which were aimed primarily at improving habitat for aquatic and riparian species. Before adopting the new rules, an environmental impact assessment was conducted in which three alternatives were considered in detail for their contributions to riparian habitat. Implications for upland species were not considered, although riparian protection has the potential to make contributions to habitat for obligate late-seral species. Effects of the three management alternatives were projected on private lands 200 years into the future, holding constant current practices on other lands managed for timber (federal, tribal, and state). The resulting distribution of late-seral forest across the Western Olympic Peninsula was compared. Simulations predicted that late-seral forest would cover between 39 and 48% of the landscape, well above the 8% that it currently occupies. Five to 21% of this late-seral forest would be on private lands (compared to <1% currently), and 71–85% on public lands (compared to 91% currently). Landscape pattern analysis indicated that the total amount of late-seral forest was significantly different among the three scenarios. However, there was no discernible difference in interior forest area, edge density, and mean distance between patches between a “no-action” alternative and the alternative that was ultimately adopted into rule. The most protective alternative had significantly more interior forest area and greater mean distance between patches, but it also had significantly higher edge density as a result of the linear nature of the riparian reserves and small patches of steep, unstable slopes. Our analysis framework will be useful for evaluating the effects of alternative management scenarios on landscape pattern across broad geographic areas with complex ownership.

Influence of roads on small rodents population in fragmented forest areas, South Korea

The road effect on small rodent population is investigated at 8 fragmented forest areas in the Baekdudaegan mountain range, South Korea in September 2001. We especially focused on the distribution and body condition of small rodents near the roads. Korean field mouse (Apodemus peninsulae) seems to be more sensitive to the existence of a road than striped field mouse (Apodemus agrarius). Korean field mouse prefers interior forest area to around road. Striped field mouse is a habitat generalist and has wide distributional range around road, but Korean field mouse is forest-inhabiting species and their distribution is limited in forest area. These results suggest the effect of road is different on each small rodent species and their habitat preferences.

Edge‐mediated effects on stand dynamic processes in forest interiors: a coupled field and simulation approach

Researchers studying forest edge effects in fragmented landscapes have begun to move beyond merely documenting changes along the edge itself to examining the dynamic influences that edges may have on processes in adjacent areas. One such “edge‐mediated effect” is the influence that edges may have on canopy gap replacement processes within the forest interior by acting as seed sources for shade‐intolerant plant species. In this paper, we coupled analyses of woody species composition in gap and non‐gap areas within the interior of an Ohio hardwood forest with a simple cellular automata model of forest dynamics. Non‐gap composition was primarily correlated with disturbance history and site conditions (topographic position and slope) while a comparable analysis using a 24‐year time series of composition in gaps showed that gap composition was related most strongly to the proximity of edge communities for the first 10–15 years. However, after 15–20 years of gap succession, composition was correlated with essentially the same variables and to the same degree as non‐gap vegetation, suggesting that the influence of edge proximity on interior stand dynamic processes was transient. These results were used to develop a simple mathematical model of stand dynamics that showed that losses of interior forest area may be much greater than typically predicted by core‐area models, which do not consider dynamic, edge‐mediated effects. Further, our findings suggest the importance of considering disturbance interval in mediating edge‐interior relationships, particularly as it may interact with forest size and shape.

Recent forest cover type transitions and landscape structural changes in northeast Minnesota, USA

Landsat TM satellite data covering an approximate 5-year interval (1990–1995) were used to quantify spatial pattern and transition rates between forest ecological states for a 2.76 million ha region in northeast Minnesota. Changes in forest cover were stratified by Ecological Subsection, management status, and by ownership categories using a 1995 digital ownership layer. Approximately 4.2% of the 1990 mature forested area was converted to early successional types by 1995. Of this 4.2%, private lands accounted for 33%, federal lands 31%, county lands 20% and state lands 16%. Notable conversion percentages by cover type category were spruce-fir (−5.3%), aspen-birch(−4.7%), jack pine (−4.6%) and black spruce(−3.0%). Transition rates were also adjusted to fit ten-year time intervals. Shannon-Weaver Eveness and edge density of cover types increased over the study period as relative contagion and interior forest area decreased. These trends suggest both smaller patches and a more even distribution of cover types. Area of upland conifers, lowland conifers and lowland hardwoods decreased while the area of mature upland hardwoods increased in most patch size classes except the > 500 ha class which showed a substantial decrease in area. The area of early successional types increased in most patch size classes. Non-industrial private forestland had the lowest proportion of interior forest of all ownership categories -decreasing by 13.5% in five years. Smaller average cut-unit size sand uncoordinated forest management is the likely cause since cutting rates between private and public forestland were similar.

Assessment of harvest blocks generated from operational polygons and forest-cover polygons in tactical and strategic planning

Manually designing harvest units for strategic planning is expensive. This paper compares blocking methods based on forest-cover polygons and manually designed harvest units. Routines are used to split and aggregate polygons into three block size distributions: (i) uniform 40-ha blocks; (ii) uniform 120-ha blocks; and (iii) by area, one-third 20 ha, one-third 60 ha, and one-third 150 ha. Three harvest rules that influence adjacency and the cutting of polygons within a block are applied to each block size distribution to compare forecasts generated by forest-cover and operational blocks. Generally, volume flows from the two methods deviate by less than 5%, and the highest deviations usually occur during the first 20 years. Projected landscape structure, as measured by interior forest area, is also similar under the two blocking methods. The results indicate that forest-cover data provide a reasonable alternative to manual blocking in tactical and strategic plans. This is significant because it removes an important barrier to timely and cost-effective planning, especially for large geographic problems where manual blocking is not an option.

Status of mushroom nematodes and their management in India.

Mushrooms are grown in almost all parts of India and the annual production is approximately 40,000 t. Several species of naturally occurring edible mushrooms are being harvested and consumed locally in tribal and interior forest areas. However, commercially only white button and oyster mushrooms are popular. They are being cultivated under semi-scientific conditions (use of partially sterilized media and casing soil, use of implements, container etc. seldom treated with formalin, etc.) with limited inputs. Other biotic stresses, such as fungi, bacteria, insects and nematodes, cause heavy losses. Hence, the commercial productivity is much less than that of other countries. Button mushrooms are generally highly susceptible to nematode infection while oyster mushrooms are relatively resistant. Although several nematode control methods have been worked out, under Indian conditions maintenance of hygienic production conditions, prophylactic (sterilized production substrates, containers, implements, gloves, etc.) and use of plant products (leaves, non-edible oil cakes of neem, pongamiya, castor, etc.) were more successful in minimizing nematode damage to mushrooms and maximizing the yields. In this review the status of mushroom nematodes, their management and future thrust areas suitable to India conditions have been discussed.

Coyote (Canis latrans) Habitat use and Mortality in Grand Teton National Park and Suburban-Agricultural Areas of Jackson Hole, Wyoming

A study of coyote (Canis latrans) habitat use and mortality in Grand Teton National Park and the suburban-agricultural land surrounding Jackson, WY was conducted between September 1999 and August 2000. This research focused on the influence of human development, habitat type, topography, and simulated wolf presence on coyote habitat use and on coyote mortality patterns in undeveloped and suburban-agricultural land. The overall goal of this project was to provide baseline information on the coyote population in Jackson Hole that can be used in the future to determine what, if any, impact wolves and human developments may have on coyotes. There were a total of fifteen radio-collared coyotes in the suburban-agricultural area and fourteen radio collared coyotes in Grand Teton National Park and adjacent areas in the National Elk Refuge and Bridger-Teton National Forest. Marked coyotes were tracked weekly using short interval telemetry relocations and triangulation to determine habitat use patterns. During the winter, track transects were skied weekly and coyote trails were backtracked and mapped using hand held GPS units to determine fine scale habitat use patterns. Coyote mortality was determined via telemetry and direct observation. Preliminary data analyses suggest that coyotes use mainly sagebrush-grasslands or forest-shrub-grass edge areas and avoid forest interior areas. Coyotes frequently use trails and roads in the undeveloped area when moving long distances. Preliminary analysis also indicates that roads and trails are used in a greater proportion than their abundance on the landscape. Coyotes were frequently observed using riparian corridors to move between open meadows in the suburban-agricultural area. There is some evidence that suggests coyotes selectively travel fences and irrigation ditches for long distances in agricultural areas. The movement data also suggests that coyotes avoid developed areas during the day and travel in these developed areas at night. The data on coyote locations suggests some avoidance of wolf urine scent grids in the undeveloped area, but not in the developed area. Coyote mortality was primarily human caused, and coyotes that were male, transient, and lived in the suburban-agricultural area were the most commonly killed animals.

Simulating the impact of landscape-level biodiversity guidelines: A case study

British Columbia, along with most of the rest of North America, is becoming preoccupied with emulating natural landscape patterns under the auspices of ecosystem management. With their Biodiversity Guidebook, BC developed one of the first collections of rules for landscape management purposes. The landscape-level rules developed therein are representative of those being developed in other areas of North America. This research compared, in simulation, a range of patterns created by these guidelines for a landscape in central BC, against those created from the historical 60 hectare two-pass system, and a "natural" disturbance regime. Results indicate that the biodiversity guidelines created more natural levels of patch sizes, interior forest area, and seral stage percentages compared to the two-pass system. However, the guidelines failed to create more natural rates of disturbance, or ranges of patch sizes and interior areas in old and mature forest. Furthermore, the implied degree of naturalness of the low, medium, and high biodiversity options did not necessarily hold true. The simulation results presented in this paper show that the concept of mimicry involves much more than originally had been supposed, and that there are limits to the degree to which mimicry can be used as a landscape management paradigm with our current knowledge and ability. A strategy for working towards a natural landscape pattern program for forest management is discussed. Key words: landscape level, biodiversity, simulation, disturbance