Alternative soilless media using olive-mill and paper waste for growing ornamental plants

Peat-based growing media are not ecologically sustainable and peat extraction threatens sensitive peatland ecosystem. In this study, olive-stone waste (OSW) and paper waste (PW) were used in different ratios—as growing media—for ornamental crop production, as peat (P) substitutes. Marigold (Calendula officinalis L.), petunia (Petunia x hybrita L.) and matthiola (Matthiola incana L.) plants were grown in (1) P (100%), (2) P:OSW (90%:10%), (3) P:OSW (70%:30%), and (4) P:OSW:PW (60%:20%:20%). The physicochemical properties of these substrates and the effects on plant growth were determined. The addition of 10–30% OSW into the substrate increased marigold height compared to plants grown in 100% peat. No differences in plant size, plant biomass (leaves and flowers), and dry matter content were found. Adding PW, in combination with OSW, maintained marigold height and total number of flowers produced to similar levels as in plants grown in 100% peat. In matthiola, adding 30% OSW into the substrate reduced plant size and fresh weight, but not plant height. No differences were observed when plants grew in lower OSW (i.e., 10%) content. Petunia’s height, its total number of flowers and flower earliness (flower opening) were increased in the presence of OSW compared to the plants grown in 100% peat. The addition of OSW did not affect petunia’s size and fresh weight among treatments. The addition of PW suppressed several plant growth-related parameters for both matthiola and petunia. The insertion of OSW did not change leaf chlorophyll content whereas the presence of PW decreased chlorophylls for marigold, petunia, and matthiola. Both OSW and PW altered the content of total phenolics and antioxidant capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) in leaves and flowers for marigold and petunia. Both 30% OSW and PW increased antioxidative enzyme metabolism due to the increased damage index and lipid peroxidation observed in plants. Leaf N and P content decreased in PW-based media, while matthiola displayed visual phytotoxicity symptoms when PW was added into the substrate. The present work indicates that up to 30% of OSW can replace peat for marigold and petunia growing and only up to 10% of OSW for matthiola, while the addition of PW on top of OSW is not recommended, so further research is needed.     

Biodegradation and detoxification of olive mill wastewater by selected strains of the mushroom genera Ganoderma and Pleurotus

Thirty-nine white-rot fungi belonging to nine species of Agaricomycotina (Basidiomycota) were initially screened for their ability to decrease olive-mill wastewater (OMW) phenolics. Four strains of Ganoderma australe, Ganoderma carnosum, Pleurotus eryngii and Pleurotus ostreatus, were selected and further examined for key-aspects of the OMW biodegradation process. Fungal growth in OMW-containing batch cultures resulted in significant decolorization (by 40-46% and 60-65% for Ganoderma and Pleurotus spp. respectively) and reduction of phenolics (by 64-67% and 74-81% for Ganoderma and Pleurotus spp. respectively). COD decrease was less pronounced (12-29%). Cress-seeds germination increased by 30-40% when OMW was treated by Pleurotus strains. Toxicity expressed as inhibition of Aliivibrio fischeri luminescence was reduced in fungal-treated OMW samples by approximately 5-15 times compared to the control. As regards the pertinent enzyme activities, laccase and Mn-independent peroxidase were detected for Ganoderma spp. during the entire incubation period. In contrast, Pleurotus spp. did not exhibit any enzyme activities at early growth stages; instead, high laccase (five times greater than those of Ganoderma spp.) and Mn peroxidases activities were determined at the end of treatment. OMW decolorization by Ganoderma strains was strongly correlated to the reduction of phenolics, whereas P. eryngii laccase activity was correlated with the effluent’s decolorization.     

Acoustic ranging in poison frogs—it is not about signal amplitude alone

Behavioral Ecology and Sociobiology - Colony size is an important predictor of annual survival and reproduction in social insects. By tracking monthly forager turn over, we measured the...     

Ecotoxicological investigations of extremely acidic mining lakes using bioassays suitable for testing at low pH

In this investigation different bioassays were used to detect the physiological and genotoxic effects of water samples of mining lakes. Especially bioassays with higher plants were used like the duckweed bioassay with Lemna minor, the cress bioassay with Lepidium sativum, the Tradescantia‐micronucleus bioassay and the Arabidopsis bioassay. In addition the algae‐motility bioassay with Euglena gracilis were used. All these bioassays were found to be suitable to investigate mining lake samples of extreme acidic character. Four mining lakes (ML 107, ML 111, ML 117, ML F) were selected. They show equally low pH‐values, but differ in size, age, hydro‐chemical and biological state. The results demonstrated that it is possible to differentiate the mining lakes based on the results of bioassays. Samples of ML 107 and 111 showed significant physiological and genotoxic effects. Water samples of both lakes caused severe damages and decreased growth at the same dilution level in all plant bioassays. ML F causes different effects on bioassays. The highest negative effect was observed on root development of L. sativum. ML 117 did not show any effects on duckweed, algae, Tradescantia or Arabidopsis bioassays. There was only a slight effect on the root development in the cress bioassay.     

A linked model of animal ecology and human behavior for the management of wildlife tourism

Wildlife tourism attractions are characterized as having intricately coupled human-wildlife interactions. Accordingly, the ability to mitigate negative impacts of tourism on wildlife necessitates research into the ecology of the system and of the human dimensions, since plans aimed at optimizing wildlife fitness must also be acceptable to tourists. We developed an integrated systems dynamics model for the management of tourist-stingray interactions at ‘Stingray City Sandbar’ (SCS), Cayman Islands. The model predicts the state of the tourism attraction over time in relation to stingray population size, stingray life expectancy, and tourist visitation under various management scenarios. Stingray population data in the model comprised growth rates and survival estimates (from mark-and-recapture data) and mortality estimates. Inputted changes in their respective rates under different management scenarios were informed by previous research. Original research on the demand of heterogeneous tourist segments for management regulations via a stated choice model was used to calculate changes in the tourist population growth rate from data supplied by the Caymanian government. The management attributes to which tourists were responsive also have anticipated effects on stingray ecology (migration and mortality), and vice versa, thus linking the two components. We found that the model's predictions over a 25-year time span were sensitive to the stingray population growth rate and alternate management options. Under certain management scenarios, it was possible to maximize both the tourist segment in favor of no management and stingray numbers while reducing stingray health. However, the most effective relative strategy included a reduction in visitor density, restricted stingray interactions, and an imposition of a small fee. Over time, although fewer stingrays were predicted to remain at SCS, they would live longer and experience fewer stochastic disease events, and the desirable tourist segment was predicted to predominate. By understanding how management will affect tourist activities and their subsequent impacts on both wildlife health and visitor satisfaction, one can explore the management alternatives that would optimize both.