Grasshopper and butterfly local congruency in grassland remnants

Bazelet, Corinna S.; Samways, Michael J.

doi:10.1007/s10841-011-9394-7

Cited by 39 publications

(22 citation statements)

References 42 publications

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“…They are well studied globally, and detailed information is available on local species (Mecenero et al, 2013). They are also suitable surrogates for other arthropod taxa locally (Bazelet & Samways, 2012) and in other regions (Thomas, 2005).…”

Section: Introductionmentioning

confidence: 99%

Divergent fire management leads to multiple beneficial outcomes for butterfly conservation in a production mosaic

Gaigher

Pryke

Samways

2019

Journal of Applied Ecology

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1. Fire is an intrinsic component of many natural ecosystems. In human-modified landscapes that occur in fire-driven ecosystems, it can be difficult to make fire management decisions, as there must be a trade-off between ideal conservation management and the practicalities of management in an altered landscape.2. We assess how biodiversity is influenced by differences in fire regime in a landscape fragmented by timber production. Here, optimal fire management for maintaining grassland integrity is not always possible, due to logistical constraints and fire risk to plantations. We investigate thicket establishment arising from reduced fire frequency, and how this affects butterfly diversity, assemblage structure, indicator species and species associations to larval host plants with different growth forms. Butterflies were sampled along a gradient of woodiness in large-scale conservation corridors that separate timber compartments.3. The two extreme stages along the successional gradient, recently burned grassland and natural forests, supported relatively diverse and complementary butterfly assemblages. Grassland corridors without fire for 2 years were as high in butterfly diversity and similar in composition to recently burned grasslands.However, corridors without fire for >5 years were encroached by thicket and supported lower butterfly diversity. Thicket, with its intermediate vegetation character, was poor habitat for species adapted to either open grassland or to forests. Also, thicket-encroached areas carry high fire risk to plantations. 4. Synthesis and applications. In this fragmented, fire-driven ecosystem, there is more than one burning strategy for achieving positive biodiversity outcomes. We recommend a divergent management approach that covers both extremes of the fire frequency continuum, with the choice depending on the stage of succession and management logistics for each site: (a) frequent burning to prevent woody encroachment in less-encroached, logistically easier sites or (b) letting succession run its course through thicket to forest by excluding fire in heavily encroached, logistically challenging sites. Both options are practicable and maintain biotopes that have high value for butterfly conservation and low fire risk to plantations. This divergent management approach is a flexible strategy that benefits both conservation and commercial interests across fire-prone plantation mosaics.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Section: Introductionmentioning

confidence: 99%

Divergent fire management leads to multiple beneficial outcomes for butterfly conservation in a production mosaic

Gaigher

Pryke

Samways

2019

Journal of Applied Ecology

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“…This vegetation type is under pressure from plantation forestry in particular (Neke & Du Plessis, 2004), although this driver is being offset by implementation of large-scale ecological networks (ENs) among commercial forestry plantations to maintain current biodiversity and ecosystem processes (Samways et al, 2010). Grasshoppers are an important component of biodiversity in these grasslands (Bazelet & Samways, 2011c), and function as indicators for other plant-interacting invertebrates, such as butterflies (Bazelet & Samways, 2011a). Apart from management guidelines to mimic natural disturbances (Samways, 2007), and to maintain a mosaic of different successional stages (Bazelet & Samways, 2011d), we know little about how these grasslands should be managed if we are to maintain the natural grasshopper assemblages.…”

Section: Introductionmentioning

confidence: 99%

Positive effects of burning and cattle grazing on grasshopper diversity

Joubert

Pryke

Samways

2016

Insect Conserv Diversity

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Grasshoppers constitute a significant proportion of invertebrate diversity in grasslands, but little is known about how fire and grazing, two of the main drivers of grassland dynamics, influence them. Here, we determine how these disturbances influence grasshopper diversity in remnant grassland ecological networks (ENs) among commercial forestry compartments in Afromontane grassland, South Africa. Sites differed in fire frequency (annual vs. longer rotation burning), time since last fire (<12 months vs. >12 months ago), and presence or absence of domestic cattle grazing. Reference sites were in an adjacent protected area (PA). We also recorded bare ground, vegetation cover, and vegetation height. Grasshopper abundance significantly benefitted from annual burning, cattle grazing, short grass, and when the last fire was <12 months prior to sampling. Fire frequency was the only disturbance with a significant effect on grasshopper species composition, but without significantly affecting species richness. In the PA, heterogeneity of dispersion was smaller in annually burned firebreaks than in sites with longer fire‐return intervals, which points to homogenisation of resident grasshopper assemblages. Although most grasshopper species favoured recently burned or grazed grassland, some preferred low or no disturbance. This illustrates a considerable range of habitat preferences in the grasshopper assemblage. Management recommendation: Burning and grazing at moderate levels should be integral to local landscape management, as these impacts benefit grasshoppers in grassland ENs. Some areas should be left undisturbed to create a mosaic of different successional stages at the landscape spatial scale, providing diverse habitat for a wide range of species.

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“…Here, we also wish to identify indicator species of different grazing regimes. Thirdly, we expect different measures of grasshopper diversity to correlate with one another, as they correlated with other taxonomic groups (Bazelet and Samways 2012). Answering these questions will help us decide upon conservation action, specifically where it involves grasshoppers in ENs within transformed landscapes.…”

Section: Introductionmentioning

confidence: 95%

“…This is because they are taxonomically well-known and ecologically sensitive, they respond reliably to changes in their local environment (Bazelet and Samways 2011a) and they mimic the response of other invertebrate groups, e.g. butterflies (Marini et al 2009, Bazelet andSamways 2012). As primary consumers, grasshoppers show greater response to local attributes than to changes in the landscape (Marini et al 2007, Bazelet andSamways 2011b), but this may vary (Batáry et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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Is cattle grazing more important than landscape heterogeneity for grasshoppers in Afromontane grassland?

Joubert¹,

Pryke²

2018

JOR

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Overgrazing is a major driver of habitat degradation, especially in southern Africa. Although grasshoppers are adapted to and benefit from natural disturbances, such as grazing by indigenous game and burning, we do not know how they respond to heavy cattle grazing, and how this response interacts with different fire regimes. We also do not know whether grasshoppers respond principally to these disturbances, to changes in the vegetation layer, or to larger landscape attributes (e.g. elevation). We addressed these questions in the topographically heterogeneous Central Midlands of KwaZulu-Natal Province, South Africa. We compared grasshopper assemblages among sites differing in grazing intensity (light, moderate and heavy), fire regime, rocky outcrops and vegetation structure, and attributes of landscape heterogeneity. The local environment (rocky outcrops, bare ground cover, grass height and total vegetation cover) was more important than landscape attributes for all measures of diversity. Grasshopper species richness was best explained by grazing intensity, with the specific response determined by fire regime. Greatest species richness was consistently recorded in heavily-grazed grassland. Thus, we found no evidence in support of the Intermediate Disturbance Hypothesis. Grasshopper assemblage composition of areas with light grazing was different from those with heavy grazing, but areas with light grazing were similar to those with moderate grazing under all fire regimes. Different suites of grasshopper species were adapted to changes in the local environment, with greatest diversity (Shannon H') associated with elevated levels of bare ground and sparse vegetation cover. The greatest proportion of rare, endemic and sensitive grasshoppers (incl. Lentula minuta, Machaeridia conspersa and Qachasia fastigiata) was associated with a greater proportion of vegetation cover. The sensitivity of grasshopper assemblages to fire-grazing interactions, and the habitat requirements of different suites of species necessitates consideration of different types (fire and grazing) as well as levels of disturbances when adjusting management practices. We recommend that conservation of rare, endemic and sensitive grasshoppers should be prioritized, as these are most vulnerable to local extirpation.

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Grasshopper and butterfly local congruency in grassland remnants

Cited by 39 publications

References 42 publications

Divergent fire management leads to multiple beneficial outcomes for butterfly conservation in a production mosaic

Divergent fire management leads to multiple beneficial outcomes for butterfly conservation in a production mosaic

Positive effects of burning and cattle grazing on grasshopper diversity

Is cattle grazing more important than landscape heterogeneity for grasshoppers in Afromontane grassland?

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