Allison Pease

• Ph.D. 2010 Texas A&M
• Professor (Assistant) at University of Missouri

The Usumacinta River is one of the largest undammed rivers in the Americas, and it drains part of the most expansive remaining rainforests north of the Amazon. In this system, snook ( Centropomus species) and tarpon ( Megalops atlanticus ) move from the southern Gulf of Mexico farther inland than is possible in many other regions. We collected fish...

Nonnative species may display unique life history traits when established in habitats with distinctive environmental and biotic contexts compared with their native ecosystems. Gulf killifish (Fundulus grandis), native to coastal habitats of the Gulf of Mexico, are established in several inland river systems where they pose a potential threat to nat...

Migratory fishes exert important influences on tropical river food webs, but these species are often most vulnerable to environmental change. Movement patterns of fishes in tropical rivers are also generally poorly understood, hindering conservation efforts. Common snook, Centropomus undecimalis , depend on connected coastal habitats for reproducti...

Biodiversity collections are experiencing a renaissance fueled by the intersection of informatics, emerging technologies, and the extended use and interpretation of specimens and archived databases. In this article, we explore the potential for transformative research in ecology integrating biodiversity collections, stable isotope analysis (SIA), a...

Few observations exist for the Kisatchie painted crayfish (Faxonius maletae), and little is known about its distribution, habitat use, or population structure. The lack of basic ecological data has led to a “Data Deficient” designation, a category of conservation concern that is often overlooked for management actions. This work provides updated da...

It is part of the Second Edition of the book "Rivers of North America", and describes limnological, biodiversity and management features of 8 Mexican rivers

Seasonal movements cued by environmental variables are a critical component of riverine fish life history. Life-history events for species such as blue sucker Cycleptus elongatus are likely cued by discharge and temperature and may be disrupted if those life-history events and environmental regimes are mismatched. However, this effect may be depend...

Characterizing functional freshwater biodiversity patterns and understanding community determinants can aid in predicting changes and prioritizing specific conservation management actions. Afrotropical freshwater systems support diverse ecological communities, including many taxonomically undescribed species, yet few studies have been undertaken in...

We used stable isotope analysis to investigate differences in Guadalupe bass (Micropterus treculii) resource use that might be associated with population‐level variation in mainstem river versus tributary stream habitats. Guadalupe bass from mainstem sites had higher δ13C and δ15N values compared to those collected in tributaries, likely reflecting...

Species conservation requires a clear understanding of habitat availability and subsequent use of those habitats. In cases where species declines have occurred and gone undetected by conservation managers , habitat alteration, fragmentation, and loss are often the largest contributors. River fragmentation often results in altered flow regimes, subs...

Alteration of flow regimes by anthropogenic activities is one of the primary environmental problems in riverine systems. Understanding how hydrologic conditions can affect ontogenetic habitat shifts of imperiled fishes is important in order to develop conservation and management strategies for each life-history stage. We examined relationships betw...

Environmental changes caused by hydrological shifts between wet and dry seasons in the tropics drive variation in resource availability and feeding interactions for riverine fish assemblages, but studies of trophic structure typically take place over short time scales that do not adequately capture this variation. In this study, we used stable isot...

During adaptive radiation, diversification within clades is limited by adaptation to the available ecological niches, and this may drive patterns of both trait and species diversity. However, adaptation to disparate niches may result in varied impacts on the timing, pattern and rate of morphological evolution. In this study, we examined the relatio...

Sedimentation in aging reservoirs generally reduces fish habitat quality and quantity, often isolating coves and pools from the main body of the reservoir. In some cases, however, habitat fragments created by sediment deposition in the river-reservoir interface zone support high fish diversity, and they could potentially replicate features of nurse...

Assessments of trophic diversity are critical for evaluating ecological integrity of habitats, but interpretations of such assessments require an understanding of variation across natural environmental gradients. This can be problematic when comparing structure of assemblages in under-studied regions or habitats, such as watersheds in dry tropical...

The Naked Goby, Gobiosoma bosc, is an estuarine species that has become established in inland freshwaters in Texas, namely in the Colorado River basin and San Antonio River basin. While G. bosc has been studied throughout its native distribution, very little is known about the ecology of the species in invaded habitats. We examined the resource use...

The historical focus of research on temperate freshwater systems has resulted in a large data gap in the tropics, particularly in Afrotropical regions. As most conceptual models have been developed in temperate systems, their applicability to Afrotropical waters is uncertain. The aim of this study is to use trait and diversity information from fres...

Understanding the degree of intraspecific variation within and among populations is a key aspect of predicting the capacity of a species to respond to anthropogenic disturbances. However, intraspecific variation is usually assessed at either limited temporal, but broad spatial scales or vice versa, which can make assessing changes in response to lo...

Fish assemblages in tropical lowland rivers are characterized by a high richness of species that feed on a diverse array of food resources. Although closely related species often have similar feeding ecology, species within the family Cichlidae display a broad spectrum of trophic niches, and resource partitioning has been inferred from studies cond...

As human population densities grow around the boundaries of protected areas in lower-income economies, there are frequently concomitant increases in environmental degradation. The purpose of this study was to examine water chemistry and the isotopic signatures of primary consumers in streams in and around a national park in the tropics to document...

1. Very little is known about the ecosystem impacts of river salinization despite expectations for global increases in salinization with growing water demand and climate change. In some rivers in the southwestern United States, salinization has occurred as a result of natural saline inputs exacerbated by flow alteration and other anthropogenic impa...

Gulf killifish, Fundulus grandis, have been introduced in the Lower Pecos River and are highly abundant in reaches of the Permian Basin region. Very little is known about the ecology of nonnative, inland populations of F. grandis. We investigated the feeding ecology of this species in the Pecos River using stomach contents analysis and laboratory f...

Patterns of association between functional traits and environmental gradients can improve understanding of species assemblage structure from local to regional scales, and therefore may be useful for natural resource management. We measured functional traits related to trophic ecology, habitat use, and life-history strategies of fishes and examined...

The taxonomic and functional structure of stream assemblages is expected to vary with changes in multi-scale environmental variables along longitudinal fluvial gradients. In some cases, fishes and stream macroinvertebrates have been shown to respond to environmental factors at different scales. We sought to examine variation in both assemblages acr...

Anthropogenic influences have been shown to disrupt natural longitudinal patterns in riverine food-web structure. The Pecos River is impacted by threats common in semi-arid regions including increased salinity, diminished discharge, altered flow regime, and conversion of watershed land for human uses. We used stable isotope analysis to characterize...

The Zebra Mussel continues to expand its range across North America despite varied efforts at containment and apparent physicochemical barriers. Early research had suggested that high water temperatures would prevent their spread and establishment in Texas. However new records in the reservoirs of the Trinity and Brazos River Basins in northern Tex...

Smallmouth bass (Micropterus dolomieu, SMB) is a broadly distributed, economically important species in the USA and Canada. Although previous research has suggested that projected climate warming may allow SMB to thrive beyond their current northern distribution, little research has been devoted to the population-level effects of climate change on...

Anthropogenic inputs of nitrogen ( N ) and phosphorus ( P ) create environmental conditions that alter biological organisation and ecosystem functioning in fresh waters. We studied 38 wadeable streams spanning a N and P gradient to contrast responses of algal and fish assemblages to nutrient enrichment. Surface water total P ( TP ) and total N ( TN...

We examined the population-level impacts of projected climate change on stream-dwelling smallmouth bass (Micropterus dolomieu, SMB) along a north-south gradient in the central U.S. Using down-scaled regional climate projections from three global climate models, we generated scenarios for thermal habitat change for four populations ranging from the...

1. The species composition of stream fish assemblages changes across the longitudinal fluvial gradient of large river basins. These changes may reflect both zonation in species distributions and environmental filtering of fish traits as stream environments change from the uplands to the lowlands of large catchments. Previous research has shown that...

Smallmouth bass (Micropterus dolomieu, SMB) is a widespread species with broad distribution throughout the eastern and central U.S. and introduced populations in many regions beyond its native range. Prior studies have shown that SMB distribution is expected to shift with predicted changes in climate, but little is known about how these changes wil...

We investigated the influences of local and landscape-scale environmental variables on fish assemblage structure among 64 stream reaches in two large river basins in central Texas. The broad spatial extent of this study region provided an opportunity to examine fish assemblage–environment relationships at multiple scales across a range of stream ty...

Background/Question/Methods Understanding how environmental variables at multiple scales influence the structure of stream fish assemblages is important for habitat assessment, stream restoration, and for predicting responses to environmental change. A focus on the functional structure of species assemblages in relation to environmental gradients...

Ecosystem processes and biological community structure are expected to change in a relatively predictable manner along fluvial gradients within river basins. Such predictions are heavily based on temperate rivers, and food web variation along fluvial gradients in Mesoamerican rivers has received limited attention. In this study, we analyzed carbon...

Background/Question/Methods An emerging view in community ecology is that a focus on functional traits as they relate to environmental gradients can reveal general patterns and improve our ability to predict responses of communities to environmental change. In this study, we applied such an approach to examine fish assemblages across a range of st...

1. Studies of mesic temperate and tropical rivers suggest an important role for floodplain habitats as nursery areas for larval and juvenile fishes. In arid-land rivers the extent and duration of flooding is diminished and habitats and resources used by larval fishes are poorly known. Our study documented habitat and resource use of larval fishes i...

The distribution and abundance of stream fishes are influenced by many factors operating at multiple scales. Understanding how environmental variables influence the structure of stream fish assemblages is important for habitat assessment, stream restoration, and for predicting responses to environmental change. An emerging view in community ecology...