Richard J. Ladle

Frequently asked questions about in vivo chlorophyll fluorescence: practical issues

The aim of this educational review is to provide practical information on the hardware, methodology, and the hands on application of chlorophyll (Chl) a fluorescence technology. We present the paper in a question and answer format like frequently asked questions. Although nearly all information on the application of Chl a fluorescence can be found in the literature, it is not always easily accessible. This paper is primarily aimed at scientists who have some experience with the application of Chl a fluorescence but are still in the process of discovering what it all means and how it can be used. Topics discussed are (among other things) the kind of information that can be obtained using different fluorescence techniques, the interpretation of Chl a fluorescence signals, specific applications of these techniques, and practical advice on different subjects, such as on the length of dark adaptation before measurement of the Chl a fluorescence transient. The paper also provides the physiological background for some of the applied procedures. It also serves as a source of reference for experienced scientists.

Chlorophyll a fluorescence as a tool to monitor physiological status of plants under abiotic stress conditions

Plants living under natural conditions are exposed to many adverse factors that interfere with the photosynthetic process, leading to declines in growth, development, and yield. The recent development of Chlorophyll a fluorescence (ChlF) represents a potentially valuable new approach to study the photochemical efficiency of leaves. Specifically, the analysis of fluorescence signals provides detailed information on the status and function of Photosystem II (PSII) reaction centers, light-harvesting antenna complexes, and both the donor and acceptor sides of PSII. Here, we review the results of fast ChlF analyses of photosynthetic responses to environmental stresses, and discuss the potential scientific and practical applications of this innovative methodology. The recent availability of portable devices has significantly expanded the potential utilization of ChlF techniques, especially for the purposes of crop phenotyping and monitoring.

Remote sensing detection of droughts in Amazonian forest canopies

*Remote sensing data are a key tool to assess large forested areas, where limitations such as accessibility and lack of field measurements are prevalent. Here, we have analysed datasets from moderate resolution imaging spectroradiometer (MODIS) satellite measurements and field data to assess the impacts of the 2005 drought in Amazonia. *We combined vegetation indices (VI) and climatological variables to evaluate the spatiotemporal patterns associated with the 2005 drought, and explore the relationships between remotely-sensed indices and forest inventory data on tree mortality. *There were differences in results based on c4 and c5 MODIS products. C5 VI showed no spatial relationship with rainfall or aerosol optical depth; however, distinct regions responded significantly to the increased radiation in 2005. The increase in the Enhanced VI (EVI) during 2005 showed a significant positive relationship (P < 0.07) with the increase of tree mortality. By contrast, the normalized difference water index (NDWI) exhibited a significant negative relationship (P < 0.09) with tree mortality. *Previous studies have suggested that the increase in EVI during the 2005 drought was associated with a positive response of forest photosynthesis to changes in the radiation income. We discuss the evidence that this increase could be related to structural changes in the canopy.

Parasites and sex: Catching the red queen.

One version of the Red Queen hypothesis suggests that sexual reproduction may be an advantage in a coevolutionary arms race. Antagonistic biotic interactions, especially those between parasite and host, are thought to represent a sufficient evolutionary force to counterbalance the supposed inefficiency of sexual reproduction. Recent experimental studies demonstrate negative frequency-dependent selection, increased parasite load in parthenogenetic races relative to sympatric sexual conspecifics and correlations between recombination rate and frequency of parasitic chromosomes. These studies provide strong empirical evidence that there is an important role for parasites in maintaining sex.

Coevolutionary dynamics of sex in a metapopulation: escaping the Red Queen

The Red Queen hypothesis for the maintenance of sexual reproduction suggests that harmful parasites and pathogens exert selection pressures on their hosts which make asexual reproduction an unstable longterm strategy. We propose, however, that host obligate asexuality can be favoured in the long term, despite the effects of parasites, under the following conditions. First, the host population structure should approximate a metapopulation. Second, the hosts or the parasites should exhibit relatively high levels of dispersal. Third, parasites must disperse independently of their hosts. In support of this view, we present a computer simulation of host-parasite coevolution in a metapopulation. The simulation demonstrates that a large difference between host and parasite dispersal rates favours an obligately asexual host reproductive strategy over an obligately sexual one. This hypothesis may explain the persistence of anciently asexual taxa, such as the bdelloid rotifers, and the patterns of dispersal seen in obligately asexual groups in general.

Bird-keeping in Indonesia: conservation impacts and the potential for substitution-based conservation responses

Bird-keeping is an extremely popular pastime in Indonesia, where there is a thriving internal market in both wild-caught and captive-bred birds. However, little is known about whether the scale of bird-keeping represents a genuine conservation threat to native populations. Here we present the results of the largest ever survey of bird-keeping among households in Indonesias five major cities. Birds were found to be urban Indonesias most popular pet (kept by 21.8% of survey households) and we conservatively estimate that as many as 2.6 million birds are kept in the five cities sampled. Of bird-keeping households, 78.5% kept domestic species and/or commercially bred species and 60.2% kept wild-caught birds that we classified into three conservation categories: native songbirds, native parrots and imported songbirds. Compared to non-bird owners, households keeping wild-caught birds in all three conservation categories were richer and better educated and households keeping domestic species did not differ in educational or socio-economic status. We conclude that bird-keeping in Indonesia is at a scale that warrants a conservation intervention and that promoting commercially-bred alternatives may be an effective and popular solution.

Are poverty and protected area establishment linked at a national scale

The debate about poverty and conservation draws mainly on local case studies, particularly of the impacts of protected areas. Although it is clear that local and contingent variables have important effects on the social and economic impacts of protected area establish- ment, it is not known whether there is a general re- lationship between national wealth and the area, number and type of protected area designated. Here we conduct such an analysis. Our results suggest that wealthy countries have a larger number of protected areas of smaller size than poorer countries. However, we find few significant relationships between indicators of poverty and the extent of protected areas at a national scale. Our analysis therefore confirms that relationships between poverty and conservation action are dynamic and locally specific. This conclusion has implications for opposing positions within the debate on poverty and conservation. Critics of conservation who build upon local case studies to argue that protected areas make a significant contribution to poverty risk exaggerating the scale of the problem. However, conservation advo- cates also need to temper their enthusiasm. Outcomes in which both poverty alleviation and conservation goals are achieved may be possible in specific circumstances but clear choices will often need to be made between conservation and livelihood goals.

Functional biogeography of oceanic islands and the scaling of functional diversity in the Azores

Significance Biogeographic theory builds upon a long history of analyzing species-diversity patterns of remote islands, but no previous studies have attempted to investigate corresponding patterns in functional traits on islands. Our analyses of functional diversity (FD) for spiders and beetles in the Azorean archipelago reveal that FD increases with species richness, which, in turn scales with island area regardless of the taxa and distributional group considered (endemics, natives, and exotics). Our results also support the hypothesis that each group contributes to FD in proportion to their species richness and that, being dominant, exotic species have significantly extended the realized trait space of the Azorean islands. Further analyses in other archipelagos are needed to establish whether our findings are representative of oceanic islands. Analyses of species-diversity patterns of remote islands have been crucial to the development of biogeographic theory, yet little is known about corresponding patterns in functional traits on islands and how, for example, they may be affected by the introduction of exotic species. We collated trait data for spiders and beetles and used a functional diversity index (FRic) to test for nonrandomness in the contribution of endemic, other native (also combined as indigenous), and exotic species to functional-trait space across the nine islands of the Azores. In general, for both taxa and for each distributional category, functional diversity increases with species richness, which, in turn scales with island area. Null simulations support the hypothesis that each distributional group contributes to functional diversity in proportion to their species richness. Exotic spiders have added novel trait space to a greater degree than have exotic beetles, likely indicating greater impact of the reduction of immigration filters and/or differential historical losses of indigenous species. Analyses of species occurring in native-forest remnants provide limited indications of the operation of habitat filtering of exotics for three islands, but only for beetles. Although the general linear (not saturating) pattern of trait-space increase with richness of exotics suggests an ongoing process of functional enrichment and accommodation, further work is urgently needed to determine how estimates of extinction debt of indigenous species should be adjusted in the light of these findings.

The (im)balance of nature: a public perception time-lag?

The last two decades have seen a conceptual shift within environmental and social sciences from an emphasis on ecosystem stability and balance to an acknowledgement of the importance of flux and change in the natural world. This has profound implications for conservation management and policy and has driven an (incomplete) transition from managing to maintain (bio)diversity and ecological stability at some historically derived “optimum” to managing to maintain important ecosystem and evolutionary processes such as nutrient cycles and migration. Here, we investigate whether this change from a “balance of nature” metaphor to a more dynamic perspective (“flux of nature”) is reflected in the representation of conservation and ecosystem management in the news media, the Internet, and the academic literature. We found that the media and the global Internet community still portray the aim of conservation science and of conservationists as being one of maintaining stability, harmony and balance.

Governing bird-keeping in Java and Bali: evidence from a household survey

The Indonesian pastime of keeping wild birds as pets is threatening the long-term survival of many songbird species on the islands of Java and Bali. Here we present the results of a large-scale household survey of bird-keeping in the six largest cites of Java and Bali that investigates: (1) the scale and conservation significance of bird-keeping and (2) the relative merits of regulatory versus market-based approaches as means to reduce the enormous demand for wild-caught birds. We found bird-keeping is widespread across social groups, with a rising demand for certain species of conservation importance. Specifically, 35.7% of households surveyed keep a bird and 57.6% of households had kept a bird in the last 10 years. Overall, we project that 584,000 households keep almost 2 million songbirds, the category of most conservation concern. Just over half of songbirds kept are wild-caught. We identified an increase in popularity (since 1999) of three native species (long-tailed shrike Lanius schach , orange-headed thrush Zoothera citrina and white-rumped shama Copsychus malabaricus ) attributable to their popularity in bird song contests. In the latter two species this has caused ‘rolling’ local extinctions across West Indonesia. Given the huge popularity and deep cultural significance of bird-keeping we argue that, in this case, lobbying for stricter regulation is undesirable, impractical and may alienate a potential future supporter base for bird conservation in Indonesia. We argue in favour of a portfolio of softer policy instruments that may include market-based and voluntary mechanisms and engage a wider range of people and organizations.