Browsing by Author "Rapson G"

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    Increased precipitation enhances soil respiration in a semi-arid grassland on the Loess Plateau, China
    (PeerJ Inc., 2021-02-02) Wang Y; Xie Y; Rapson G; Ma H; Jing L; Zhang Y; Zhang J; Li J; Zhu B
    BACKGROUND: Precipitation influences the vulnerability of grassland ecosystems, especially upland grasslands, and soil respiration is critical for carbon cycling in arid grassland ecosystems which typically experience more droughty conditions. METHODS: We used three precipitation treatments to understand the effect of precipitation on soil respiration of a typical arid steppe in the Loess Plateau in north-western China. Precipitation was captured and relocated to simulate precipitation rates of 50%, 100%, and 150% of ambient precipitation. RESULTS AND DISCUSSION: Soil moisture was influenced by all precipitation treatments. Shoot biomass was greater, though non-significantly, as precipitation increased. However, both increase and decrease of precipitation significantly reduced root biomass. There was a positive linear relationship between soil moisture and soil respiration in the study area during the summer (July and August), when most precipitation fell. Soil moisture, soil root biomass, pH, and fungal diversity were predictors of soil respiration based on partial least squares regression, and soil moisture was the best of these. CONCLUSION: Our study highlights the importance of increased precipitation on soil respiration in drylands. Precipitation changes can cause significant alterations in soil properties, microbial fungi, and root biomass, and any surplus or transpired moisture is fed back into the climate, thereby affecting the rate of soil respiration in the future.
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    Karaka (Corynocarpus laevigatus): native taonga (treasure) or environmental weed?
    (Taylor and Francis Group, 2024-09-05) McAlpine KG; Cory S; Cox BTM; McLeod T; Rapson G; Roskruge NR; Shepherd LD
    Karaka (Corynocarpus laevigatus J.R. Forst. & G. Forst.) is an endemic New Zealand tree species that attracts polarising views and controversy. Prior to the arrival of humans in New Zealand, karaka was probably restricted to warmer areas of the northern North Island, but it now occurs throughout much of New Zealand, including on Rēkohu/Chatham Island (where it is known as kōpi). Genetic analyses have shed light on the evolutionary origins of karaka and its translocation history. Karaka holds significant cultural and historical value for Māori and Moriori, but it is also viewed as an environmental weed outside its natural range due to its capacity to outcompete resident native vegetation and disrupt local ecosystems. Karaka fruit can be toxic to dogs and other animals, including humans, if not prepared correctly before consumption. The management of karaka in New Zealand presents a unique challenge that exemplifies the complexities inherent in balancing cultural values with ecological integrity. The aim of this paper is to bring together all these different perspectives and explore avenues for future management strategies that accommodate both the cultural significance and the ecological impact of karaka. An informed, culturally sensitive management strategy that involves mana whenua can pave the way for a future where both cultural and ecological aspects of the karaka tree are given due consideration where appropriate. Such an approach could also inform the management of other native plant species that become invasive outside their natural range both in New Zealand and internationally.