Exotic pest insects: another perspective on coffee and conservation

Research on crop systems and biodiversity conservation in the tropics has mainly been concerned with how low to mid intensity agricultural systems can benefit from adjacent natural habitats by receiving ecosystem services from natural biodiversity. One intensively studied crop in this framework is coffee. Positive effects are relatively easy to quantify by comparing coffee yield and by recording native species diversity. However, a largely overlooked issue is how agricultural areas affect native organisms in adjacent natural habitats, for example through movement of pest species that could impose a risk of degrading these habitats. We give an example from Mauritius, where an introduced coffee pest severely reduces the reproductive success of a threatened endemic plant species. We argue that such effects may be more common than suggested by the literature, especially when crop and native plants are congeneric. In the long term, such negative effects may degrade natural habitats, thereby causing ecosystem services derived from these habitats to declin

Understanding demographic limiting factors to species recovery: Nest-site suitability and breeding ecology of Phelsuma guentheri on Round Island, Mauritius

The island of Mauritius in the Mascarenes has already suffered high levels of extinction, and habitat destruction and invasive alien species have pushed many of the remaining endemic species to the brink of extinction. Round Island, a small island northeast of Mauritius, is home to remnant populations of several reptile species that were once distributed across Mauritius. One of the most threatened of these is Günther’s gecko Phelsuma guentheri, where despite extensive management efforts, population size remains small and below expectation. We identify determinants of nest-site suitability across Round Island, and examine whether suitable nest sites are a limiting factor for the abundance of P. guentheri. Over one breeding season, we recorded and monitored a high number (269) of nest sites harbouring a total of 1475 eggs. We used the number of eggs at each nest, and the hatching success as proxies for nest-site suitability. To study the reproductive behaviour of P. guentheri, we installed trail cameras at three nest sites. We did not find the expected high frequency of use of hardwood trees as nest sites, as found on Ile aux Aigrettes to the southeast of Mauritius, probably because hardwood trees are still relatively sparse and small on Round Island. Instead, the endemic palm Latania loddigesii was the most used nest sites, harbouring 78.8% of all nests with 56.3% of all eggs. Hatching success was high for palm nest sites (90.6%), rock surfaces (91.8%), and on the endemic screw pine Pandanus vandermeeschii (96%), rates that are similar to that reported from hardwood trees on Ile aux Aigrettes (~90%). Communal nesting occurred on all substrates, with up to five individuals using the same nest site. Egg-laying took place at dusk or at night, lasting around 30 min, whereas hatching occurred mostly during the day, lasting 2–107 min. Females laid eggs every 34 days on average, and produced up to four clutches of 1–2 eggs each within the season. We conclude that P. guentheri does not suffer from nest site limitation on Round Island, and that reproductive success is high in terms of both numbers of eggs laid and hatching success, likely due to ongoing habitat restoration. Further research is needed to investigate the factors inhibiting abundance and distribution of P. guentheri on Round Island

Pollination ecology and circadian patterns of inflorescence opening of the Madagascan climber Dalechampia aff. bernieri (Euphorbiaceae)

Floral morphology often directly influences interactions with pollinators, but less is known about the role of extrafloral structures. We studied the relationship between bract motility, floral structural specialization and pollination in Dalechampia aff. bernieri, an endemic Madagascan species with floral structures indicating specialized buzz-pollination.Wemeasured circadian bract angles in 47 inflorescences from 11 plants of D. aff. bernieri; in addition, we recorded any flower-visiting insects observed. The inflorescences hadmotile bracts with mean angles varying from about 50° at 00h00 to about 90° at 10h45. They were visited by buzz-pollinating Nomia viridilimbata bees (Halictidae), but also by non-buzz-pollinating Liotrigona bees (Apidae). The temporal pattern of bractmotility observed in D. aff. bernieri may represent an extra-floral specialization to reduce visitation by non-pollinating visitors while maximizing visitation by diurnal buzz-pollinating bees

Seed Dispersal and Establishment of Endangered Plants on Oceanic Islands: The Janzen-Connell Model, and the Use of Ecological Analogues

BACKGROUND: The Janzen-Connell model states that plant-specific natural enemies may have a disproportionately large negative effect on progeny close to maternal trees. The majority of experimental and theoretical studies addressing the Janzen-Connell model have explored how it can explain existing patterns of species diversity in tropical mainland areas. Very few studies have investigated how the model's predictions apply to isolated oceanic islands, or to the conservation management of endangered plants. Here, we provide the first experimental investigation of the predictions of the Janzen-Connell model on an oceanic island, in a conservation context. In addition, we experimentally evaluate the use of ecological analogue animals to resurrect the functional component of extinct frugivores that could have dispersed seeds away from maternal trees. METHODOLOGY/PRINCIPAL FINDINGS: In Mauritius, we investigated seed germination and seedling survival patterns of the critically endangered endemic plant Syzygium mamillatum (Myrtaceae) in relation to proximity to maternal trees. We found strong negative effects of proximity to maternal trees on growth and survival of seedlings. We successfully used giant Aldabran tortoises as ecological analogues for extinct Mauritian frugivores. Effects of gut-passage were negative at the seed germination stage, but seedlings from gut-passed seeds grew taller, had more leaves, and suffered less damage from natural enemies than any of the other seedlings. CONCLUSIONS/SIGNIFICANCE: We provide the first experimental evidence of a distance-dependent Janzen-Connell effect on an oceanic island. Our results potentially have serious implications for the conservation management of rare plant species on oceanic islands, which harbour a disproportionately large fraction of the world's endemic and endangered plants. Furthermore, in contrast to recent controversy about the use of non-indigenous extant megafauna for re-wilding projects in North America and elsewhere, we argue that Mauritius and other oceanic islands are ideal study systems in which to empirically explore the use of ecological analogue species in restoration ecology

Farlige kryds – afhængig af definitioner og datakilder

Både i Danmark og i udlandet er sammenhængen mellem trafikulykkers sværhedsgrad og frekvens kun dårligt undersøgt. Dette kan skyldes, at der typisk bruges politi­ eller ambulanceregistrerede ulykker, dette giver en skævvridning mod de alvorlige ulykker og en underrepræsentation af de lette ulykker. På Fyns registreres alle henvendelser til skadestuerne detaljeret, når de skyldes en trafikrelateret ulykke. Ved Ulykkes Analyse Gruppen har vi for perioden 1.1.2002 til 1.12.2007 undersøgt alle trafikrelateret ulykker, hvor ulykken er sket i et kryds. Formålet har været at undersøge, om forskellige måder at definere farlige kryds på, leder frem til forskellige grupper af farlige kryds – er det for eksempel de samme kryds der har mange ulykker og alvorlige ulykker. Desuden er det undersøgt, om kryds der er farlige ifølge skadestuernes data også kendes af politiet

Science for a wilder Anthropocene: synthesis and future directions for trophic rewilding research

Trophic rewilding is an ecological restoration strategy that uses species introductions to restore top-down trophic interactions and associated trophic cascades to promote self-regulating biodiverse ecosystems. Given the importance of large animals in trophic cascades and their widespread losses and resulting trophic downgrading, it often focuses on restoring functional megafaunas. Trophic rewilding is increasingly being implemented for conservation, but remains controversial. Here, we provide a synthesis of its current scientific basis, highlighting trophic cascades as the key conceptual framework, discussing the main lessons learned from ongoing rewilding projects, systematically reviewing the current literature, and highlighting unintentional rewilding and spontaneous wildlife comebacks as underused sources of information. Together, these lines of evidence show that trophic cascades may be restored via species reintroductions and ecological replacements. It is clear, however, that megafauna effects may be affected by poorly understood trophic complexity effects and interactions with landscape settings, human activities, and other factors. Unfortunately, empirical research on trophic rewilding is still rare, fragmented, and geographically biased, with the literature dominated by essays and opinion pieces. We highlight the need for applied programs to include hypothesis testing and science-based monitoring, and outline priorities for future research, notably assessing the role of trophic complexity, interplay with landscape settings, land use, and climate change, as well as developing the global scope for rewilding and tools to optimize benefits and reduce human–wildlife conflicts. Finally, we recommend developing a decision framework for species selection, building on functional and phylogenetic information and with attention to the potential contribution from synthetic biology

Pollination ecology and circadian patterns of inflorescence opening of the Madagascan climber Dalechampia aff. bernieri (Euphorbiaceae)

Floral morphology often directly influences interactions with pollinators, but less is known about the role of extrafloral structures. We studied the relationship between bract motility, floral structural specialization and pollination in Dalechampia aff. bernieri, an endemic Madagascan species with floral structures indicating specialized buzz-pollination. We measured circadian bract angles in 47 inflorescences from 11 plants of D. aff. bernieri; in addition, we recorded any flower-visiting insects observed. The inflorescences had motile bracts with mean angles varying from ~50° at 00h00 to ~90° at 10h45. They were visited by buzz-pollinating Nomia viridilimbata bees (Halictidae), but also by non-buzz-pollinating Liotrigona bees (Apidae). The temporal pattern of bract motility observed in D. aff. bernieri may represent an extra-floral specialization to reduce visitation by non-pollinating visitors while maximizing visitation by diurnal buzz-pollinating bee

The High-Density Ionized Gas in the Central Parsecs of the Galaxy

We report the results from observations of H30$\alpha$ line emission in Sgr A West with the Submillimeter Array at a resolution of 2\arcsec and a field of view of about 40\arcsec. The H30$\alpha$ line is sensitive to the high-density ionized gas in the minispiral structure. We compare the velocity field obtained from H30$\alpha$ line emission to a Keplerian model, and our results suggest that the supermassive black hole at Sgr A* dominates the dynamics of the ionized gas. However, we also detect significant deviations from the Keplerian motion, which show that the impact of strong stellar winds from the massive stars along the ionized flows and the interaction between Northern and Eastern arms play significant roles in the local gas dynamics.Comment: 4 pages, 2 figure