The impact of climate change induced alterations of streamflow and stream temperature on the distribution of riparian species

Abstract

Distributions of riparian species will likely shift due to climate change induced alterations in temperature and rainfall patterns, which alter stream habitat. Spatial forecasting of suitable habitat in projected climatic conditions will inform management interventions that support wildlife. Challenges in developing forecasts include the need to consider the large number of riparian species that might respond differently to changing conditions and the need to evaluate the many different characteristics of streamflow and stream temperature that drive species-specific habitat suitability. In particular, in dynamic environments like streams, the short-term temporal resolution of species occurrence and streamflow need to be considered to identify the types of conditions that support various species. To address these challenges, we cluster species based on habitat characteristics to select habitat representatives and we evaluate regional changes in habitat suitability using short-term, temporally explicit metrics that describe the streamflow and stream temperature regime. We use stream-specific environmental predictors rather than climatic variables. Unlike other studies, the stream-specific environmental predictors are generated from the time that species were observed in a particular reach, in addition to long term trends, to evaluate habitat preferences. With species occurrence data from local monitoring surveys and streamflow and stream temperature modeled from downscaled Coupled Model Intercomparison Project ‐ Phase 5 (CMIP5) climate projections, we predict change in habitat suitability at the end-of-century. The relative importance of hydrology and stream temperature varied by cluster. High altitudinal, cold water species’ distributions contracted, while lower elevation, warm water species distributions expanded. Modeling with short-term temporally explicit environmental metrics did produce different end-of-century projections than using long-term averages for some of the representative species. These findings can help wildlife managers prioritize conservation efforts, manage streamflow, initiate monitoring of species in vulnerable clusters, and address stressors, such as passage barriers, in areas projected to be suitable in future climate conditions.

Constructing ecological indices for urban environments using species distribution models

“…This region is within a Mediterranean climatic zone, receiving the bulk of its annual rainfall (40 cm) during the winter season (Hill et al 2016). While the environment of this region is heavily modified through the expansion of impervious surfaces, irrigation, river channelization and transportation networks, it has been found to contain a diverse, albeit heavily altered, set of species (Pataki et al 2013;Li et al 2019;Adams et al 2020;Rogers et al 2020).…”

A new species of Protosticta Selys, 1885 (Odonata: Zygoptera: Platystictidae) from Western Ghats, India

“…nov. is an inhabitant of the first-order streams of mid-elevation forests of Anamalais in the Western Ghats. These species from seepages, streamlets, and hill streams are the most vulnerable in the wake of climate change (Rogers et al 2020). As per Nair et al (2021), the checklist of odonates of Western Ghats currently stands at 207 species with 80 endemics.…”

Modelling future changes to the hydrological and thermal regime of unaltered streams using projected changes in climate to support planning for sensitive species management

“…These metrics were selected based on their descriptive power for hydrological patterns and their biological importance for supporting the native species in southern California. Relationships of these metrics and multiple riparian species are explored in Rogers et al, (2020).…”

“…Like the streamflow metrics, these metrics were selected for their importance in identifying suitable habitat (for example, Welsh et al, (2001) and to describe different aspects of the stream temperature regime. Relationships of the stream temperature metrics and multiple riparian species are also discussed in (Rogers et al, 2020). Future stream temperature metrics were calculated from averaged air temperature predictions across the three GCMs using the same regression models (Walton et al, 2015), assuming the other predictor variables stay constant.…”