Analysing DNA that organisms release into the environment (environmental DNA, or eDNA) has enormous potential for assessing rare and cryptic species. At present the method is only reliably used to assess the presence-absence of species in natural environments, as seasonal influences on eDNA in relation to presence, abundance, life stages and seasonal behaviours are poorly understood. A naturally colonised, replicated pond system was used to show how seasonal changes in eDNA were influenced by abundance of adults and larvae of great crested newts (Triturus cristatus). Peaks in eDNA were observed in early June when adult breeding was coming to an end, and between mid-July and mid-August corresponding to a peak in newt larval abundance. Changes in adult body condition associated with reproduction also influenced eDNA concentrations, as did temperature (but not rainfall or UV). eDNA concentration fell rapidly as larvae metamorphosed and left the ponds. eDNA concentration may therefore reflect relative abundance in different ponds, although environmental factors can affect the concentrations observed. Nevertheless, eDNA surveys may still represent an improvement over unadjusted counts which are widely used in population assessments but have unreliable relationships with population size.
1. Identifying the drivers of population fluctuations in spatially distinct populations remains a significant challenge for ecologists. Whereas regional climatic factors may generate population synchrony (i.e. the Moran effect), local factors including the level of density dependence may reduce the level of synchrony. Although divergences in the scaling of population synchrony and spatial environmental variation have been observed, the regulatory factors that underlie such mismatches are poorly understood. Few previous studies have investigated how density-dependent processes andpopulation-specific responses to weather variation influence spatial synchrony at both local and regional scales. We addressed this issue in a pond-breeding amphibian, the great crested newt Triturus cristatus. We used capture-recapture data collected through long-term surveys in five T. cristatus populations in Western Europe.3. In all populations-and subpopulations within metapopulations-population size, annual survival and recruitment fluctuated over time. Likewise, there was considerable variation in these demographic rates between populations and within metapopulations. These fluctuations and variations appear to be context-dependent and more related to site-specific characteristics than local or regional climatic drivers.We found a low level of demographic synchrony at both local and regional levels.Weather has weak and spatially variable effects on survival, recruitment and population growth rate. In contrast, density dependence was a common phenomenon (at least for population growth) in almost all populations and subpopulations. 4. Our findings support the idea that the Moran effect is low in species where the population dynamics more closely depends on local factors (e.g. population density and habitat characteristics) than on large-scale environmental fluctuation (e.g. regional climatic variation). Such responses may have far-reaching consequences for the long-term viability of spatially structured populations and their ability to respond to large-scale climatic anomalies.
A revised and updated checklist of the herpetofauna of the Krau Wildlife Reserve (KWR), Pahang is presented, which includes 61 species of amphibians and 65 species of reptiles. Five species of amphibians are listed under revised names i.e. Hylarana labialis, H. picturata, Ansonia latiffi, Microhyla mantheyi and Rhacophorus norhayatae; and two species are listed as new locality records for KWR: Hylarana cf. siberu and Theloderma licin. The amphibians and reptiles recorded in KWR are approximately 56% and 22% of the total number of species recorded from Peninsular Malaysia, respectively.
Abstract. Basri NIA, Zakaria N. 2021. Butterfly communities (Insecta: Lepidoptera) at two recreational areas in Sungai Petani, Kedah, Peninsular Malaysia. Biodiversitas 22: 5039-5047. The knowledge on the butterfly diversity, especially in various habitats in Kedah is still poor. A study was conducted to determine and compare the diversity of butterflies at two recreational areas in Sungai Petani, Kedah, namely Bukit H and Taman Jubli Perak. This study was carried out starting from January 2021 until March 2021 with a total of nine sampling occasions at each site. Visual Encounter Survey (VES) was chosen as a sampling method. The butterflies were captured using a sweep net from 9am to 11am and 12pm to 2pm for each sampling site. A total of 145 individuals from 13 species from four families of butterflies were recorded. The most abundant species were recorded from the family Nymphalidae. Chilades pandava was the most abundant species obtained from the two recreational areas. From the t-test analysis, there was no significant difference between the diversity of Bukit H and Taman Jubli Perak. Shannon and Simpson's diversity indices showed both sites were interpreted as moderately low in diversity. This may be due to the different types of vegetation that exist at both sampling sites. This study will contribute to the first record of butterflies in Sungai Petani, Kedah, Peninsular Malaysia.
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