Ryan Wasserman results 29
· Newest (Page 1/2, per page 25)
Author: Ryan Wasserman ×Clear All Filters
Search Results
Human activities continue to facilitate biological invasions, profoundly impacting our environment and economy. Plants and insects constitute the majority of invasions to date, with facilitative links established between them, particularly in terrestrial habitats. These relationships remain understudied in aquatic environments, including potential associations between aquatic invasive plants and disease vectors such as mosquit...
Assessing biological invasion predatory impacts through interaction strengths and morphological trophic profilingNARA Subscribed
Biological invasions are a major stressor on ecosystems worldwide, but tools to predict their predatory impact remain limited. Here, we quantified invader impacts using two complementary approaches: functional responses (to reveal per capita and multiple predator interaction strengths) and ecomorphology (to reveal trophic profiles and competitive overlap). We compared Mozambique tilapia Oreochromis mossambicus, a native southe...
Salinisation of arid temporary pools alters crustacean hatching success but not phenology dynamicsNARA Subscribed
The widespread acceleration of freshwater salinisation due to human activities, such as pollution, resource extraction and urbanisation coupled with climate change, poses a significant threat to aquatic ecosystems. Limited work has been directed towards salinisation effects in temporary wetland systems. These systems are characterised by unique crustacean communities reliant on dormant egg production. We assessed salinisation...
The analysis of food web structures has increased the understanding of the dynamics of organisms belonging to different trophic levels. In this study, the diet of two native species, Glossogobius callidus and Gilchristella aestuaria , was assessed in the presence of two non‐native species, Oreochromis mossambicus and Gambusia affinis , in irrigation ponds, Eastern Cape Province, South Africa. The proportion of dietary items co...
Invasive alien species impacts might be mediated by environmental factors such as climatic warming. For invasive predators, multiple predator interactions could also exacerbate or dampen ecological impacts. These effects may be especially pronounced in highly diverse coastal ecosystems that are prone to profound and rapid regime shifts. We examine emergent effects of warming on the strength of intraspecific multiple predator e...
The river goby Glossogobius callidus is native to freshwater and estuarine habitats in South Africa. Individuals [21.1–144.4 mm total length ( L T )] were sampled from impoundments in the Sundays River Valley, Eastern Cape, from February 2014 to March 2015. The largest female was 137.2 mm L T , and the largest male was 144.4 mm L T . Length‐at‐50% maturity was 75.2 ± 2.1 mm L T for males and 76.2 ± 2.0 mm L T for females. Abso...
Assessing multiple predator, diurnal and search area effects on predatory impacts by ephemeral wetland specialist copepodsNARA Subscribed
Predator–prey interaction strengths can be highly context-dependent. In particular, multiple predator effects (MPEs), variations in predator sex and physical habitat characteristics may affect prey consumption rates and thus the persistence of lower trophic groups. Ephemeral wetlands are transient ecosystems in which predatory copepods can be numerically dominant. We examine the interaction strengths of a specialist copepod Pa...
Sex demographics alter the effect of habitat structure on predation by a temporary pond specialistNARA Subscribed
Habitat structure can profoundly influence interaction strengths between predators and prey. Spatio-temporal habitat structure in temporary wetland ecosystems is particularly variable because of fluctuations in water levels and vegetation colonisation dynamics. Demographic characteristics within animal populations may also alter the influence of habitat structure on biotic interactions, but have remained untested. Here, we inv...
Functional responses can unify invasion ecologyNARA Subscribed
We contend that invasion ecology requires a universal, measurable trait of species and their interactions with resources that predicts key elements of invasibility and ecological impact; here, we advocate that functional responses can help achieve this across taxonomic and trophic groups, among habitats and contexts, and can hence help unify disparate research interests in invasion ecology.