Land Use

Natural resource managers are often expected to achieve both environmental protection and
economic development even when there are fundamental trade-offs between these goals. Adaptive management
provides a theoretical structure for program administrators to balance social priorities in the presence
of trade-offs and to improve conservation targeting. We used the case of Mexico’s federal Payments for
Hydrological Services program (PSAH) to illustrate the importance of adaptive management for improving
program targeting. We documented adaptive elements of PSAH and corresponding changes in program eligibility
and selection criteria. To evaluate whether these changes resulted in enrollment of lands of high
environmental and social priority, we compared the environmental and social characteristics of the areas
enrolled in the program with the characteristics of all forested areas in Mexico, all areas eligible for the
program, and all areas submitted for application to the program. The program successfully enrolled areas of
both high ecological and social priority, and over time, adaptive changes in the program’s criteria for eligibility
and selection led to increased enrollment of land scoring high on both dimensions. Three factors facilitated
adaptive management in Mexico and are likely to be generally important for conservation managers: a
supportive political environment, including financial backing and encouragement to experiment from the
federal government; availability of relatively good social and environmental data; and active participation
in the review process by stakeholders and outside evaluators.

Historical forest management can heavily affect contemporary forest management and conservation. Yet, relatively little is known about century-long changes in forests, and that limits the understanding of how past management and land tenure affect current forestry practice and ecosystem conservation. Our goal here was to examine the relationship between historical forest management (as depicted by historical forest cover, species composition, age structure and harvesting data) and contemporary forest patterns in Romania. Romania represents an ideal case-study to examine the effects of historical forest management, because it experienced multiple shifts in forest management regimes since the 1800s due to Austro-Hungarian, Ottoman, Romanian, Soviet and later EU policy influences, and because it is both a conservation hotspot harboring some of the largest old-growth forest in Europe, and an important source of timber for international markets. We reviewed forestry literature and statistics since the 19th century to reconstruct a time-series of forest cover, composition, disturbance patterns, and ownership patterns and interpreted these data in light of institutional changes. We further assessed changes in forest cover, forest harvest, species composition and age structure between two points in time (1920s and 2010s) at the county level, using a combination of historical forest statistics, remote sensing data and modeled forest composition. We complemented our national data with three case studies for which we had stand-level historical and contemporary forest management data. We found that forest area increased in Romania since 1924 by 5% and that the annual rate of forest harvest between 2000 and 2013 was half of the annual rate between 1912 and 1922, which indicates high potential for forest biodiversity conservation. However, the composition, distribution, and age structure of contemporary forests is also substantially different from historical forests. We found an overall increase in coniferous species and several deciduous species (such as Tilia, Populus, Betula, Alnus sp.), a spatial homogenization of species composition, and more even-aged stands. We also observed a drop from 14% to 9% in the relative abundance of old forests (>100 years). Spikes in forest harvest coincided with times of widespread forest privatization, and drastic institutional changes, such as agrarian reforms, or the onset and collapse of the Soviet Regime. Overall, our results suggest that effects of past management, land ownership and institutional changes can persist for centuries, and affect forest ecosystem composition, health and structure, and consequently ecosystem services and habitat availability. Our findings are scientifically important because they provide evidence for legacies of past management and for the effects of forest privatization on harvesting rates. Our findings are also relevant to forest management and conservation practice, because they highlight that environmentally sound management over long time periods is essential for sustainable forestry and old-growth forest protection in Europe and elsewhere.

A variety of land-use and land-cover (LULC) models operating at scales from local to global have bee developed in recent years, including a number of models that provide spatially explicit, multi-class LUL projections for the conterminous United States. This diversity ofmodeling approaches raises the question:how consistent are their projections offuture land use?We compared projections from six LULC modelin applications for the United States and assessed quantitative, spatial, and conceptual inconsistencies. Eac set of projections provided multiple scenarios covering a period from roughly 2000 to 2050. Given th unique spatial, thematic, and temporal characteristics of each set of projections, individual projection were aggregated to a common set of basic, generalized LULC classes (i.e., cropland, pasture, forest, range and urban) and summarized at the county level across the conterminous United States. We found ver little agreement in projected future LULC trends and patterns among the different models. Variabilit among scenarios for a given model was generally lower than variability among different models, i terms of both trends in the amounts of basic LULC classes and their projected spatial patterns. Eve when different models assessed the same purported scenario, model projections varied substantially Projections of agriculturaltrends were often far above the maximum historical amounts, raising concern aboutthe realismofthe projections. Comparisons amongmodels were hindered bymajor discrepancies i categorical definitions, and suggest a need for standardization of historical LULC data sources. To capture broader range of uncertainties, ensemble modeling approaches are also recommended. However,the vas inconsistencies among LULC models raise questions about the theoretical and conceptual underpinning of current modeling approaches. Given the substantial effects thatland-use change can have on ecologica and societal processes, there is a need for improvement in LULC theory and modeling capabilities t improve acceptance and use of regional- to national-scale LULC projections for the United States an elsewhere.