Mammal inventories in tropical forests are often difficult to carry out, and many elusive species are missed or only reported from interviews with local people. Camera traps offer a new tool for conducting inventories of large-and mediumsized terrestrial mammals. We evaluated the efficiency of camera traps based on data from two surveys carried out at a single site during 2 consecutive years. The survey efforts were 1440 and 2340 camera days, and 75 and 86% of the 28 largeand medium-sized terrestrial mammal species known to occur at the site were recorded. Capture frequencies for different species were highly correlated between the surveys, and the capture probability for animals that passed in front of the cameras decreased with decreasing size of the species. Camera spacing and total survey area had little influence on the number of species recorded, with survey effort being the main factor determining the number of recorded species. Using a model we demonstrated the exponential increase in survey effort required to record the most elusive species. We evaluated the performance of different species richness estimators on this dataset and found the Jackknife estimators generally to perform best. We give recommendations on how to increase efficiency of camera trap surveys exclusively targeted at species inventories.
Efforts to mitigate climate change through the Reduced Emissions from Deforestation and Degradation (REDD) depend on mapping and monitoring of tropical forest carbon stocks and emissions over large geographic areas. With a new integrated use of satellite imaging, airborne light detection and ranging, and field plots, we mapped aboveground carbon stocks and emissions at 0.1-ha resolution over 4.3 million ha of the Peruvian Amazon, an area twice that of all forests in Costa Rica, to reveal the determinants of forest carbon density and to demonstrate the feasibility of mapping carbon emissions for REDD. We discovered previously unknown variation in carbon storage at multiple scales based on geologic substrate and forest type. From 1999 to 2009, emissions from land use totaled 1.1% of the standing carbon throughout the region. Forest degradation, such as from selective logging, increased regional carbon emissions by 47% over deforestation alone, and secondary regrowth provided an 18% offset against total gross emissions. Very high-resolution monitoring reduces uncertainty in carbon emissions for REDD programs while uncovering fundamental environmental controls on forest carbon storage and their interactions with land-use change.
Florida Bay is a shallow, seagrass‐dominated embayment on the southern tip of Florida. Variation of C, N, and P content of leaves of Thalassia testudinum was measured on two spatial scales: locally (10–100 m) in relation to a point source of nutrients associated with a bird colony in eastern Florida Bay and regionally (10– 100 km) across all of the bay. Locally, the P content of leaves decreased from a high of 0.16% P (wt/wt) 30 m from the nutrient source to a low of 0.08% 120 m from the source; the C and N content (34.9 and 2.1%) was independent of distance from the nutrient source. Due to variations in P content, C : P and N : P, but not C : N, varied locally. Regionally, P content varied greatly, from 0.05 to 0.20%; C (29.4–39.5%) and N (1.7–2.7%) showed considerably less variation. Variation in C : P and N : P across the bay encompassed a range nearly as great as reported for all seagrasses around the world combined; C : N showed little variation. Local variation around the nutrient point source indicated that C : P and N : P were indicators of P availability, and trend analysis of the regional spatial variation in C : P and N : P showed that P availability was greatest in northwest, and least in eastern, Florida Bay. This pattern mirrored abundance of seagrasses and productivity in the bay. T. testudinum from the bay appears to be P limited and N saturated, even in the sparsest seagrass communities.
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