Jane M. Read

APPLICATION OF 1-M AND 4-M RESOLUTION SATELLITE DATA TO ECOLOGICAL STUDIES OF TROPICAL RAIN FORESTS

Understanding the current status of the worlds tropical rain forests (TRF) can be greatly advanced by global coverage of remotely sensed data at the scale of individual tree crowns. In 1999 the IKONOS satellite began offering worldwide 1-m panchromatic and 4-m multispectral data. Here we show that these data can be used to address diverse aspects of forest ecology and land-use classification in the tropics. Using crowns of emergent trees as control points, we georeferenced a 600-ha subset of IKONOS 1-m and 4-m data from an August 2000 image of the La Selva Biological Station, Costa Rica (root mean square error 5 4.3 m). Crown area measured on the image was highly correlated with crown area for the same tree measured from the ground. Using a 1988 aerial photograph as a baseline, all trees .1 m diameter in a long-term study that died over the ensuing 12-year period, and that could be located in the photograph, were detected as missing in the IKONOS image (N 5 7). Crown growth for large trees visible on both images averaged 12 m 2 /yr (N 5 16). We thus demonstrate that IKONOS imagery can provide data on four variables necessary for doing demographic research: tree size, location, mortality, and growth. Stand basal area, estimated aboveground biomass, and percentage of the canopy .15 m tall for 18 0.5-ha permanent forest inventory plots in old growth were all highly sig- nificantly correlated with different indices derived from the IKONOS data. We used summary statistics from the original IKONOS data as well as derived indices to characterize nine areas with well-documented land-use histories. Secondary forests were clearly separable from the other sites. One of the secondary forests was 40 years old, suggesting that IKONOS data can be used to detect significantly older secondary forest than is possible with coarser resolution satellite data. The selectively logged forest was distinguishable by measuring the size of the largest crowns on the 1-m image. This suggests a range of applications for detecting and quantifying biomass degradation due to selective logging and edge effects. Satellite data at 1-m and 4-m resolution make possible a truly global approach to fine spatial resolution remote-sensing studies of TRF ecology and land use.

Large-Scale Environmental Monitoring by Indigenous Peoples

Changes in vertebrate populations in tropical ecosystems are often understood to occur at large spatial and temporal scales. Understanding these dynamics and developing management responses when they are affected by hunting and land-use change require research and monitoring at large spatial scales. Data collection at such scales can be accomplished only through the participation of locally resident nonscientists. To assess the feasibility of rigorous, scientifically valid data collection under such conditions, we describe the design and management of a three-year study of the relationships among socioeconomic factors, hunting behavior, and wildlife population dynamics in a 48,000-square-kilometer, predominantly indigenous region of Amazonia. All of the data in the study were collected by locally recruited and trained indigenous technicians. We describe data collection and verification systems adapted to the culturally influenced data-collection practices of these technicians and propose protocols and improvements on our methodology to guide future large-scale research-and-monitoring projects.

Space, Place, and Hunting Patterns among Indigenous Peoples of the Guyanese Rupununi Region

Hunting remains an important subsistence activity for many indigenous peoples of the Neotropics. This paper describes indigenous hunting patterns using a mixed-methods approach in southern Guyana from a space and place perspective that takes into account both biophysical and cultural/spiritual factors. Findings confirm those of others, that distance from community, mediated by characteristics of the biophysical environment, impacts where hunters go. Mapping of the spiritual landscape, however, demonstrates that sense of place is also important. This paper argues that researchers and managers should be careful to incorporate both the local environmental and cultural/spiritual contexts in studies that inform biodiversity and sustainable resource-use management.

Documenting Land Cover History of a Humid Tropical Environment in Northeastern Costa Rica Using Time-Series Remotely Sensed Data

A time-series of aerial photography and Landsat TM data were compiled for an area of the Caribbean lowlands of northeastern Costa Rica from 1960–1996. Geo-referenced, ground-based information was collected in 1996 and 1997. Changes in land cover were mapped and landscape fragmentation was examined using landscape pattern metrics. By 1996 the area was characterized by a complex mosaic of forests, pastures, and crop lands of different ages and disturbance histories. The most important forces driving land use changes were colonization, infrastructure development, and changes in export markets, but the spatial patterns of land use change were determined by the physical landscape. In terms of long-term forest health and conservation, there are three considerations: (1) whilst forests remain an important component of the unprotected landscape in the region, and deforestation rates have declined, the forests are highly fragmented and the area exposed to edge effects is high; (2) the secondary forests in the area are young and transient in nature; and (3) never cleared forests are in good condition, but they are susceptible to disturbance in the future.

Foliar Nitrogen Responses to the Environmental Gradient Matrix of the Adirondack Park, New York

Maps derived from remote sensing of canopy nitrogen (N) provide a potential avenue to make spatially explicit, regional-scale predictions of the vital forest ecosystem services that are coupled to the cycling of N and carbon. Yet, to fully use canopy N maps in this capacity, it is necessary to understand how canopy species with differing resource strategies will adjust foliar N in response to environmental variability. In this study, we relate a regional survey of foliar N data from a diverse set of forest tree species in the Adirondack Park, New York, to a holistic matrix of environmental gradients thought to control spatial variability of foliar N. Stepwise multiple regression models developed for each species indicate that neighboring species and abiotic gradients of resource availability play a lesser role, and anthropogenic influences (caused by historic disturbances and atmospheric N deposition) are the strongest drivers of spatial variability in foliar N. Moreover, we find that the plasticity of the total foliar N response to measured environmental variability is strongly related to two indexes of a species’ resource strategy—leaf mass per area and shade tolerance. Collectively, these results (1) further demonstrate the utility of an environmental gradient matrix approach to studying complex ecosystems; (2) emphasize the potentially dominant role of humans in controlling future nutrient cycling, even within this “forever wild” forest ecosystem; and (3) suggest that spatially explicit measurements of foliar N, environmental gradients, and plant resource strategies might provide a pathway to map and forecast ecosystem services at regional scales.

THE SPATIAL PATTERN OF NITROGEN CYCLING IN THE ADIRONDACK PARK, NEW YORK

Maps of canopy nitrogen obtained through analysis of high-resolution, hyperspectral, remotely sensed images now offer a powerful means to make landscape-scale to regional-scale estimates of forest N cycling and net primary production (NPP). Moreover, recent research has suggested that the spatial variability within maps of canopy N may be driven by environmental gradients in such features as historic forest disturbance, temperature, species composition, moisture, geology, and atmospheric N deposition. Using the wide variation in these six features found within the diverse forest ecosystems of the 2.5 million ha Adirondack Park, New York, USA, we examined linkages among environmental gradients and three measures of N cycling collected during the 2003 growing season: (1) field survey of canopy N, (2) field survey of soil C:N, and (3) canopy N measured through analysis of two 185 x 7.5 km Hyperion hyperspectral images. These three measures of N cycling strongly related to forest type but related poorly to all other environmental gradients. Further analysis revealed that the spatial pattern in N cycling appears to have distinct inter- and intraspecific components of variability. The interspecific component, or the proportional contribution of species functional traits to canopy biomass, explained 93% of spatial variability within the field canopy N survey and 37% of variability within the soil C:N survey. Residual analysis revealed that N deposition accounted for an additional 2% of variability in soil C:N, and N deposition and historical forest disturbance accounted for an additional 2.8% of variability in canopy N. Given our finding that 95.8% of the variability in the field canopy N survey could be attributed to variation in the physical environment, our research suggests that remotely sensed maps of canopy N may be useful not only to assess the spatial variability in N cycling and NPP, but also to unravel the relative importance of their multiple controlling factors.

Spatial analyses of logging impacts in Amazonia using remotely sensed data

(see, e.g., Sist (2000) for details on RIL operations), which Performances of selected spatial methods are investigated for include a range of impacts from road openings to treefall gap characterizing canopy disturbance in a reduced-impact log- openings of various sizes, present a good opportunity to examging operation in central Amazonia using Landsat-7 ETM and ine the performances of spatial methods in detecting canopy Ikonos visible, near-infrared, and normalized difference vege- disturbances at the low end of logging impacts. tation index data. Texture, fractal dimension (D), and Moran’s This paper describes the potential of spatial methods for I index of spatial autocorrelation were calculated for (1) 10- characterizing managed tropical forests using satellite data. ha plots representing logged (LF), logged excluding major roads The objectives of this study were to (1) investigate the sensitivand patios (L), and old-growth (OG) forest; and (2) 335-ha plots ity of Ikonos and Landsat 7 ETM data to selective logging representing LF and OG. impacts in a central Amazonian forest, (2) investigate the perIkonos data were sensitive to roads, patios, and some formance of selected spatial methods for characterizing logging gaps, whereas ETM data were only sensitive to major reduced-impact logging activities along a simple disturbance logging features. The spatial methods were effective at charac- gradient, and (3) examine the effects of measurement and geoterizing the different logging feature treatments at both plot graphic scales on the outcomes of these methods. This was sizes; DTPSA and Moran’s I were most sensitive to fine-scale achieved through comparing the behavior of selected spatial surface details. The spatial methods show potential for moni- methods at different measurement and geographic scales using toring and management of logging activities over landscape Ikonos and ETM data over two plot sizes. The methods evaluscales. The importance of scale, given the ever-increasing ated were texture, spatial autocorrelation, and fractal dimenchoice of remotely sensed data, is emphasized. sion. The research was carried out in a moist tropical forest reduced-impact logging operation near Manaus, Brazil, where

Teaching Introductory Geographic Information Systems through Problem-Based Learning and Public Scholarship.

Teaching geographic information systems (GIS) requires linking concepts with technical skills, which can be challenging, especially in standard lecture and laboratory-format courses. This paper reports on an introductory undergraduate GIS course that incorporated a community-driven problem-based learning exercise as a major component of the course. Analysis of student performance and course evaluations indicates that the exercise was effective in aiding student learning of GIS, while also teaching research and other professional development skills, and providing insight into an important social issue within their community. Benefits and cautions are discussed from the perspective of students, instructor, university and local community.

Line Transect Surveys Underdetect Terrestrial Mammals: Implications for the Sustainability of Subsistence Hunting

Conservation of Neotropical game species must take into account the livelihood and food security needs of local human populations. Hunting management decisions should therefore rely on abundance and distribution data that are as representative as possible of true population sizes and dynamics. We simultaneously applied a commonly used encounter-based method and an infrequently used sign-based method to estimate hunted vertebrate abundance in a 48,000-km2 indigenous landscape in southern Guyana. Diurnal direct encounter data collected during three years along 216, four-kilometer -long transects consistently under-detected many diurnal and nocturnal mammal species readily detected through sign. Of 32 species analyzed, 31 were detected by both methods; however, encounters did not detect one and under-detected another 12 of the most heavily hunted species relative to sign, while sign under-detected 12 never or rarely collected species relative to encounters. The six most important game animals in the region, all ungulates, were not encountered at 11–40% of village and control sites or on 29–72% of transects where they were detected by sign. Using the sign methodology, we find that tapirs, one of the terrestrial vertebrates considered most sensitive to overexploitation, are present at many sites where they were never visually detected during distance sampling. We find that this is true for many other species as well. These high rates of under-detection suggest that behavioral changes in hunted populations may affect apparent occurrence and abundance of these populations. Accumulation curves (detection of species on transects) were much steeper for sign for 12 of 16 hunted species than for encounters, but that pattern was reversed for 12 of 16 species unhunted in our area. We conclude that collection of sign data is an efficient and effective method of monitoring hunted vertebrate populations that complements encounter and camera-trapping methods in areas impacted by hunting. Sign surveys may be the most viable method for large-scale, management-oriented studies in remote areas, particularly those focused on community-based wildlife management.

Drawing on traditional knowledge to identify and describe ecosystem services associated with Northern Amazon’s multiple-use plants

ABSTRACT Tropical multiple-use plants provide an array of ecosystem services, including providing food for wildlife, non-timber forest products (NTFPs) and commercial logs. As land-use and land-cover change (LUCC) continues in tropical forests, questions on whether the ecosystem services they provide can be sustained become more pressing. As particular species of plants are targeted for provisioning services, such as commercial logging, the implications for other ecosystem services are often unknown. In this paper we drew on the traditional knowledge of the Makushi and Wapishiana Amerindians of Southern Guyana, and multiple-use plants to gauge the ecosystem services that may be compromised as tropical forests undergo change. An inventory of tree and palm species was classified into one or more of four resource-use classes: commercial timber, wildlife food, traditional uses or no known use. Species that intersected more than one resource use were defined as multiple-use species, and occupied four primary classes – wildlife food/commercial timber, commercial timber/traditional uses, wildlife food/traditional uses and wildlife food/commercial timber/traditional uses. Traditional knowledge allowed us to identify plant species and describe how they are used for provisioning, cultural and supporting ecosystem services and shaping our understanding of the multiple dimensions of ecosystem services associated with a single species. EDITED BY John Parrotta