chambers), but only two (erroneously given as one by Videler) have generated clear U-shaped relat... more chambers), but only two (erroneously given as one by Videler) have generated clear U-shaped relationships. This has often been taken as evidence that flight mechanics is wrong, which is a false conclusion given that the theory strictly speaking refers to P mech . The curves will have the same shape only if the conversion efficiency is the same across all speeds. More recent studies using a strain gauge to measure the force applied by the flight muscle to the humerus (wing) and the work loop technique lead to clear U-shaped relationships for three species investigated [2]. Videler reviews all available studies on flight costs and the methods used to obtain them, and then uses a sub-set (classified as 'reliable') to derive allometric equations for flight cost.
Over the last 20 years a new generation of climate models have been developed that link atmospher... more Over the last 20 years a new generation of climate models have been developed that link atmosphere models to dynamic vegetation models (coupled atmosphere-biosphere models). These models are able to capture key feedbacks between the changing climate and changing ecosystems, providing more realistic forecasts of anthropogenic climate change. Moreover, the biosphere model can be regionally calibrated to provide more geographically specific predictions about future trajectories of environmental change over the next century. We identify four potential uses of coupled atmosphere-biosphere models for conservation: (i) more accurate and regionally specific forecasts of climate change; (ii) better understanding of carbon cycling, a key ecosystem service; (iii) better placement and design of protected areas, and; (iv) improved modeling of different land-use scenarios. Realizing these objectives will require better integration and communication between modeling and conservation communities and the development of specific visualization and planning tools that allows these complex models to be fully integrated into conservation planning.
Accurate estimates of photosynthetically active radiation (PAR) are critical for the development ... more Accurate estimates of photosynthetically active radiation (PAR) are critical for the development of realistic models of plant productivity. However, in many areas such as the vast Amazon region of South America, there have been few empirical studies of PAR. Here, we analyzed the relationship between PAR and broadband solar irradiance (R s ) and formulated models to estimate PAR in two experimental sites (pasture and forest) in the Brazilian Amazon. Three different models of increasing complexity were developed based on information from R s (model 1), R s and clearness index (k t ; model 2), and R s , k t , and water vapor pressure (model 3). Estimates of PAR were generated for each season and for the entire year. All models had very high determination coefficients and indices of agreement for both pasture and forest sites. This strongly supports the use of R s and k t to produce robust estimates of PAR. The results obtained by annual models were close than that found by seasonal models, demonstrating that a single annual model is able to estimate PAR, albeit with lower accuracy.
In the original paper the coefficients of the linear regressions in were not placed in the correc... more In the original paper the coefficients of the linear regressions in were not placed in the correct order. The correct ones are as follows:
Net primary production (NPP) is a key variable for monitoring and understanding the impacts of en... more Net primary production (NPP) is a key variable for monitoring and understanding the impacts of environmental change on ecosystems and for generating realistic global and regional carbon budgets. In this paper we present a regional algorithm (RATE) for automatically monitoring the rate of carbon fixation (as measured by NPP) of tropical forests in South America. The algorithm is based on a modification of the SITE ecosystem model and uses data obtained from the procedures for aggregation and correction of data from the MOD12Q1 and MOD15A2 products and meteorological data from the National Centers for Environmental Prediction (NCEP). A correction procedure for the MOD15A2 Leaf area index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) used by the RATE algorithm produced satisfactory LAI and FAPAR estimates when compared against observed values. The algorithm was successfully validated in eight field sites from two types of tropical forests in South America (Amazon rainforest and the Atlantic forest), producing an average error of only 4.72%. When applied to Amazonia, RATE indicates that NPP showed little variation in the 2005 and 2010 drought years (NPP = 1.28 kg-C m − 2 year − 1 ) in comparison to nondrought years (NPP = 1.31 kg-C m − 2 year − 1 ). RATE also provides some limited evidence for small decreasing trends in Amazonia carbon assimilation during the period 2001-2010.
The rediscovery of a species that was putatively considered to be extinct can provide valuable da... more The rediscovery of a species that was putatively considered to be extinct can provide valuable data to test biogeographical hypotheses about population decline and range collapse. Moreover, such rediscoveries often generate much-needed publicity and additional funds for the conservation of rare species and habitats. However, like extinction, rediscovery is challenging to define. In this perspective we argue that the 'loss' of a species and its subsequent rediscovery can be understood in terms of the interplay among four socio-ecological factors: (1) the state of knowledge of species loss and rediscovery;
Apps are small task-orientated programs with the potential to integrate the computational and sen... more Apps are small task-orientated programs with the potential to integrate the computational and sensing capacities of smartphones with the power of cloud computing, social networking, and crowdsourcing. They have the potential to transform how humans interact with nature, cause a step change in the quantity and resolution of biodiversity data, democratize access to environmental knowledge, and reinvigorate ways of enjoying nature. To assess the extent to which this potential is being exploited in relation to nature, we conducted an automated search of the Google Play Store using 96 nature-related terms. This returned data on ~36 304 apps, of which ~6301 were nature-themed. We found that few of these fully exploit the full range of capabilities inherent in the technology and/or have successfully captured the public imagination. Such breakthroughs will only be achieved by increasing the frequency and quality of collaboration between environmental scientists, information engineers, compu...
Amphibians and reptiles (herps) are the most abundant and diverse vertebrate taxa in tropical eco... more Amphibians and reptiles (herps) are the most abundant and diverse vertebrate taxa in tropical ecosystems. Nevertheless, little is known about their role in maintaining and regulating ecosystem functions and, by extension, their potential value for supporting ecosystem services. Here, we review research on the ecological functions of Neotropical herps, in different sources (the bibliographic databases, book chapters, etc.). A total of 167 Neotropical herpetology studies published over the last four decades (1970 to 2014) were reviewed, providing information on more than 100 species that contribute to at least five categories of ecological functions: i) nutrient cycling; ii) bioturbation; iii) pollination; iv) seed dispersal, and; v) energy flow through ecosystems. We emphasize the need to expand the knowledge about ecological functions in Neotropical ecosystems and the mechanisms behind these, through the study of functional traits and analysis of ecological processes. Many of these functions provide key ecosystem services, such as biological pest control, seed dispersal and water quality. By knowing and understanding the functions that perform the herps in ecosystems, management plans for cultural landscapes, restoration or recovery projects of landscapes that involve aquatic and terrestrial systems, development of comprehensive plans and detailed conservation of species and ecosystems may be structured in a more appropriate way. Besides information gaps identified in this review, this contribution explores these issues in terms of better understanding of key questions in the study of ecosystem services and biodiversity and, also, of how these services are generated.
Aim To assess the hypotheses that compound leaves of trees in the Amazon forest are an adaptation... more Aim To assess the hypotheses that compound leaves of trees in the Amazon forest are an adaptation to drought and/or rapid growth.
Scotland's tourism trade grosses £2.5 billion annually and supports 180,000 jobs; whale-watching ... more Scotland's tourism trade grosses £2.5 billion annually and supports 180,000 jobs; whale-watching is an important part of this activity. Whales and dolphins are the country's number one wildlife attraction and with 11,770 km of coastline the potential for the Scottish industry is huge. In rural areas it can provide as much as 12% of local income. During the tourist season of 2000, questionnaires and telephone interviews were used to investigate the sustainability of Scottish whale-watching. 48 operators cooperated providing economic and environmental information. Most operators were found to be local people (72.4%), supporting five or less full-time equivalent jobs (86.4%). Over half of those questioned (63.2%) had alternative incomes and no formal training in wildlife tourism or business management (70.8%); 89.5% of respondents stated that they follow a code of conduct. The East Coast and Western Isles show the best-perceived trends in tourist numbers. Whale-watching in Scotland is shown to have potential for growth but a need to be regulated and managed from within the industry to ensure environmental and economic sustainability into the future.
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Papers by Richard Ladle